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An investigation of the reactions of butylene and isobutane in the presence of concentrated sulfuric acid using a wetted wall reactor
Howerton, Murlin T.
AN INVESTIGATION OF THE REACTIONS OF BUTYLENE AND ISOBUTANE IN THE PRESENCE OF CONCENTRATED SULFURIC ACID USING A WETTED WALL REACTOR Approved as Head of the A Thesis By Murlin Thomas Howerton ?if May, 19U9 to^gtyle and content recommended...: Department of Chemical Engineering AN INVESTIGATION OF THE REACTIONS OF BUTYLENE AND ISOBUTANE IN THE PRESENCE OF CONCENTRATED SULFURIC, ACID USING A WETTED WALL REACTOR A Thesis By Murlin Thomas Howerton May, 19U9 AN INVESTIGATION OF THE REACTIONS...
Lyondell develops one step isobutylene process
Not Available
This paper reports that Lyondell Petrochemical Co., Houston, has developed a one step process to convert normal butylenes to isobutylene, a key component of methyl tertiary butyl ether (MTBE). MTBE is expected to become the additive of choice among U.S. refiners to blend oxygenated gasolines required by 1990 amendments to the Clean Air Act. Lyondell Pres. and Chief Executive Officer Bob Gower the the new process could help assure adequate supplies of MTBE to meet U.S. demand for cleaner burning fuels. Lyondell estimates the capital cost of building a grassroots plant to produce isobutylene with the new process would be less than half the cost of a grassroot plant to produce isobutylene with existing technology starting with normal butane.
Capture isobutylene with glycol
Knifton, J.F. (Texaco Chemical's Austin Research Lab. TX (United States))
The separation of butenes present in C-4 streams (generated as a result of steam or catalytic cracking) is becoming increasingly important as the butenes find expanded applications in the production of methyl-t-butyl ether (MTBE), methyl methacrylate, butyl rubber, and linear low-density polyethylene. Available methods of separation include selective extraction with a liquid solvent (usually an acid); the use of addition reactions with suitable alcohols, acids, or water; selective polymerization and physical separation by absorbents. Three currently important separation processes for isobutylene production are an extraction route using mineral acid, the dehydration of tert-butanol, and the cracking of MTBE. As part of the research into solid acid catalysis for the generation of glycol tert-butyl monoethers, the authors have demonstrated an alternative C-4 separation process using solid inorganic acid catalysts and involving the intermediate preparation of glycol ethers. This new C-4 separation scheme could be particularly attractive to existing glycol producers who may also have a market, or internal need, for glycol monoalkyl ethers, as well as those who do not have MTBE capacity but still require pure isobutylene as a chemical intermediate or comonomer building block. The process is described.
Alkylation of mixed olefins with isobutane in a stratco chemical reactor
Vichailak, M. [ABB Lummus Global Inc., Houston, TX (United States); Hopper, J.R.; Yaws, C.L. [Lamar Univ., Beaumont, TX (United States); Pike, R.W. [Louisiana State Univ., Baton Rouge, LA (United States)
The 17 reaction model for the sulfuric acid alkylation of isobutane with propylene as proposed by Langley and Pike has been used to simulate the effluent refrigeration reactor. The simulation conditions selected to minimize the formation of light and heavy by-product were determined to be: Temperature: 9 - 10 {degrees}C,- Isobutane/Olefin Ratio: 8 - 10; % Volume of Acid: 50 %. The reactor effluent composition from the simulation program has been used to compare with several sets of published data with reasonable agreement. This model has been extrapolated to simulate the alkylation of isobutane with butylenes and amylenes. The model will be optimized with commercial data. 9 refs., 6 figs., 1 tab.
Catalyst and process development for synthesis gas conversion to isobutylene
Anthony, R.G.; Akgerman, A.
The objectives of this project are to develop a new catalyst, the kinetics for this catalyst, reactor models for trickle bed, slurry and fixed bed, and simulate the performance of fixed bed trickle flow reactors, slurry flow reactors, and fixed bed gas phase reactors for conversion of a hydrogen lean synthesis gas to isobutylene.
Catalyst and process development for synthesis gas conversion to isobutylene. Final report, September 1, 1990--January 31, 1994
Anthony, R.G.; Akgerman, A.
Previous work on isosynthesis (conversion of synthesis gas to isobutane and isobutylene) was performed at very low conversions or extreme process conditions. The objectives of this research were (1) determine the optimum process conditions for isosynthesis; (2) determine the optimum catalyst preparation method and catalyst composition/properties for isosynthesis; (3) determine the kinetics for the best catalyst; (4) develop reactor models for trickle bed, slurry, and fixed bed reactors; and (5) simulate the performance of fixed bed trickle flow reactors, slurry flow reactors, and fixed bed gas phase reactors for isosynthesis. More improvement in catalyst activity and selectivity is needed before isosynthesis can become a commercially feasible (stand-alone) process. Catalysts prepared by the precipitation method show the most promise for future development as compared with those prepared hydrothermally, by calcining zirconyl nitrate, or by a modified sol-gel method. For current catalysts the high temperatures (>673 K) required for activity also cause the production of methane (because of thermodynamics). A catalyst with higher activity at lower temperatures would magnify the unique selectivity of zirconia for isobutylene. Perhaps with a more active catalyst and acidification, oxygenate production could be limited at lower temperatures. Pressures above 50 atm cause an undesirable shift in product distribution toward heavier hydrocarbons. A model was developed that can predict carbon monoxide conversion an product distribution. The rate equation for carbon monoxide conversion contains only a rate constant and an adsorption equilibrium constant. The product distribution was predicted using a simple ratio of the rate of CO conversion. This report is divided into Introduction, Experimental, and Results and Discussion sections.
Transport of Injected Isobutane by Thermal Groundwater in Long...
Injected Isobutane by Thermal Groundwater in Long Valley Caldera, California, USA, In- Water-Rock Interaction-11 Jump to: navigation, search OpenEI Reference LibraryAdd to library...
Lyondell`s new isobutylene route could fuel an MTBE capacity boost
Rotman, D.; Wood, A.
Driven by the hot growth prospects for methyl tert-butyl ether (MTBE), Lyondell Petrochemical (Houston) has developed a route to isobutylene it claims can produce the MTBE feedstock at half the capital cost of alternative synthesis technology. If proved, the process will be used in a new 7500-10,000 bbl/day MTBE plant at Channelview, TX. Lyondell also hopes to license the technology. {open_quotes}With expanding MTBE capacity, we will have to have new routes to isobutylene,{close_quotes} says Bob G. Gower, president and CEO of Lyondell. {open_quotes}We think this is a good fit within Lyondell, but also that it is important technology.{close_quotes} Gower declines to detail its specifics, but says it is a one-step isomerization of n-butenes to isobutylene. The firm has tested the process at a pilot unit and plans a demonstration unit in 1992.
Catalyst and process development for synthesis gas conversion to isobutylene. Quarterly report, January 1, 1992--March 31, 1992
Anthony, R.G.; Akgerman, A.
The objectives of this project are to develop a new catalyst, the kinetics for this catalyst, reactor models for trickle bed, slurry and fixed bed, and simulate the performance of fixed bed trickle flow reactors, slurry flow reactors, and fixed bed gas phase reactors for conversion of a hydrogen lean synthesis gas to isobutylene.
Heat transfer coefficients for propane (R-290), isobutane (R-600a), and 50/50 mixture of propane and isobutane
Mathur, G.D. [Zexel USA Corp., Decatur, IL (United States)
Tube-side heat transfer coefficients for single-phase flow, evaporation, and condensation are presented for propane (R-290), isobutane (R-600a), and a 50/50 mixture (by weight) of propane and isobutane. Heat transfer coefficients have been presented for smooth tubes based on the standard correlations available in the literature for pure refrigerants. The correlations for evaporation and condensation have previously been verified for R-12 and other refrigerants. The correlations for evaporation and condensation have previously been verified for R-12 and other refrigerants. The mass flux of the refrigerant is varied over a wide range that is typically encountered in residential, commercial, and automotive applications. Evaporation temperatures of {minus}6.7 C (20 F) and 4.4 C (40 F) and condensation temperatures of 37.8 C (100 F) and 48.9 C (120 F) have been used for this investigation. The heat transfer coefficients for hydrocarbons (R-290, R-600a, R-290/R-600a) have been compared with R-12 and R-134a. The REFPROP computer program developed by the National Institute of Standards and Technology (NIST) has been used to determine the thermodynamic properties for R-290, R-600a, and R-290/R-600a. This study shows that the heat transfer coefficients for hydrocarbons are significantly higher than those for both R-12 and R-134a. For the range of refrigerant temperatures and mass flux studied, single-phase vapor heat transfer coefficients for hydrocarbons are greater by 234% to 259% in comparison to R-12 and are greater by 167% to 181% in comparison to R-134a. The single-phase liquid heat transfer coefficients for hydrocarbons are greater by 193% to 245% in comparison to R-12; and are greater by 155% to 198% in comparison to R-134a. Average evaporative heat transfer coefficients for hydrocarbons are greater by 194% to 238% in comparison to R-12 and are greater by 157% to 192% in comparison to R-134a. Finally, average condensing coefficients are greater by 220% to 233% in comparison to R-12 and are greater by 177% to 187% in comparison to R-134a. Tables 3 through 6 show a summary of the heat transfer coefficient enhancement of the hydrocarbons in comparison to both R-12 and R-134a.
Catalyst and process development for synthesis gas conversion to isobutylene. Quarterly report, October 1, 1993--December 31, 1993
Anthony, R.G.; Akgerman, A.
The objectives of this project are to develop a new catalyst; the kinetics for this catalyst; reactor models for trickle bed, slurry and fixed bed reactors; and to simulate the performance of fixed bed trickle flow reactors, slurry flow reactors, and fixed bed gas phase reactors for conversion of a hydrogen lean synthesis gas to isobutylene. A hydrogen-lean synthesis gas with a ratio of H{sub 2}/CO of 0.5 to 1.0 is produced from the gasification of coal, lignite, or biomass. Isobutylene is a key reactant in the synthesis of methyl tertiary butyl ether (MTBE) and of isooctanes. MTBE and isooctanes are high octane fuels used to blend with low octane gasolines to raise the octane number required for modern automobiles. The production of these two key octane boosters is limited by the supply of isobutylene. MTBE, when used as an octane enhancer, also decreases the amount of pollutants emitted from the exhaust of an automobile engine.
Single event kinetic modeling of solid acid alkylation of isobutane with butenes over proton-exchanged Y-Zeolites�
Martinis Coll, Jorge Maximiliano
Complex reaction kinetics of the solid acid alkylation of isobutane with butenes over a proton-exchanged Y-zeolite has been modeled at the elementary step level. Starting with a computer algorithm that generated the reaction ...
Single event kinetic modeling of solid acid alkylation of isobutane with butenes over proton-exchanged Y-Zeolites
Martinis Coll, Jorge Maximiliano
runs. An experimental investigation of the solid acid alkylation process was carried out in a fixed bed catalytic reactor operating with an excess of isobutane under isothermal conditions at moderate temperatures (353-393 K) in liquid phase...
Synthesis of Isobutene and Isobutane from Synthesis Gas. A Literature Review Since 1992
Petkovic, Lucia M.; Ginosar, Daniel M.
The isosynthesis reaction is commonly referred as the reaction that converts selectively synthesis gas to isobutene and isobutane. The main feature of this reaction is the production of branched hydrocarbons in higher proportion with respect to linear hydrocarbons than expected from thermodynamic equilibrium and with a molecular weight distribution favoring iso-C4 hydrocarbons. This article reviews and summarizes isosynthesis research results reported in the open scientific literature with emphasis on the articles published in the last two decades.
Ignition properties of n-butane and iso-butane in a rapid compression machine
Gersen, S.; Darmeveil, J.H. [Gasunie Engineering and Technology, P.O. Box 19, 9700 MA Groningen (Netherlands); Mokhov, A.V. [Laboratory for Fuel and Combustion Science, University of Groningen, Nijenborgh 4, 9747 AG Groningen (Netherlands); Levinsky, H.B. [Gasunie Engineering and Technology, P.O. Box 19, 9700 MA Groningen (Netherlands); Laboratory for Fuel and Combustion Science, University of Groningen, Nijenborgh 4, 9747 AG Groningen (Netherlands)
Autoignition delay times of n-butane and iso-butane have been measured in a Rapid Compression Machine in the temperature range 660-1010 K, at pressures varying from 14 to 36 bar and at equivalence ratios {phi} = 1.0 and {phi} = 0.5. Both butane isomers exhibit a negative-temperature-coefficient (NTC) region and, at low temperatures, two-stage ignition. At temperatures below {proportional_to}900 K, the delay times for iso-butane are longer than those for the normal isomer, while above this temperature both butanes give essentially the same results. At temperatures above {proportional_to}720 K the delay times of the lean mixtures are twice those for stoichiometric compositions; at T < 720 K, the equivalence ratio is seen to have little influence on the ignition behavior. Increasing the pressure from 15 bar to 30 bar decreases the amplitude of the NTC region, and reduces the ignition delay time for both isomers by roughly a factor of 3. In the region in which two-stage ignition is observed, 680-825 K, the duration of the first ignition stage decreases sharply in the range 680-770 K, but is essentially flat above 770 K. Good quantitative agreement is found between the measurements and calculations for n-butane using a comprehensive model for butane ignition, including both delay times in the two-stage region, with substantial differences being observed for iso-butane, particularly in the NTC region. (author)
Support shape effect in metal oxide catalysis: ceria nanoshapes supported vanadia catalysts for oxidative dehydrogenation of iso-butane
Wu, Zili [ORNL; Schwartz, Viviane [ORNL; Li, Meijun [ORNL; Rondinone, Adam Justin [ORNL; Overbury, Steven {Steve} H [ORNL
The activation energy of VOx/CeO2 catalysts in oxidative dehydrogenation of iso-butane was found dependent on the shape of ceria support: rods < octahedra, closely related to the surface oxygen vacancy formation energy and defects amount of the two ceria supports with different crystallographic surface planes.
Formation of paramagnetic species upon radiolysis of a polycarbonate-poly(butylene terephthalate) system
Orlov, A.Yu.; Fel`dman, V.I.; Sukhov, F.F. [Karpov Institute of Physical Chemistry, Moscow (Russian Federation)
The formation of paramagnetic species upon low-temperature radiolysis of a polycarbonate-poly(butylene terephthalate) (PC-PBTP) system was studied by ESR spectroscopy. The radiation-chemical yields of paramagnetic species in pure polymers and their blends with various blending times were measured. The decrease of G values for samples with a long blending time was explained by the suppression of formation of neutral radicals from the PC units. The formation of CO-separated radical pairs, which result from the PC fragments, is suppressed efficiently as the blending time increases. It is concluded that the spectral parameters of the radical pairs are the most sensitive features to the change in the microenvironment of the radiolysis products.
Gasoline and Diesel Fuel Update (EIA)
combining isobutane with olefin hydrocarbons (e.g., propylene, butylene) through the control of temperature and pressure in the presence of an acid catalyst, usually sulfuric...
Gasoline and Diesel Fuel Update (EIA)
combining isobutane with olefin hydrocarbons (e.g., propylene, butylene) through the control of temperature and pressure in the presence of an acid catalyst, usually sulfuric...
Development of a catalyst for conversion of syngas-derived materials to isobutylene. Quarterly report number 19, October 1--December 31, 1995
Spehlmann, B.C.
The goals of this project are to develop a catalyst and process for the conversion of syngas to isobutanol. After identification and optimization of key catalyst and process characteristics, the commercial potential of the process is to be evaluated by an economic analysis. From independent process variable studies to investigate the conversion of a methanol/ethanol feed to isobutanol, the best performance to date has been achieved with the 2% Pt on Zn/Mn/Zr oxide catalyst. Using Hyprotech Hysim v2.5 process simulation software, and considering both gas and liquid recycle loops in the process flow diagram, the overall carbon conversion is 98% with 22% selectivity to isobutanol. The expected production of isobutanol is 92 MT/day from 500 MT/day of methanol and 172 MT/day of ethanol feed. An additional 13 MT/day of isobutryaldehyde intermediate is recovered in the liquid product and vent streams. Because of the low selectivity (22%) of the methanol conversion catalyst to isobutanol, the process is uneconomical, even if the isobutanol is valued as a solvent ($903/MT) and not as isobutylene for MTBE production ($352/MT).
Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]
741 317 267 1,325 IsobutaneIsobutylene 206 7 213 155 55 170 380 Other HydrocarbonsHydrogenOxygenates 512 0 512 29 18 0 47 Other HydrocarbonsHydrogen 0 0 0 28 0 0 28...
PSA Vol 1 Tables Revised Ver 2 Print.xls
Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]
741 317 245 1,303 IsobutaneIsobutylene 206 7 213 155 55 184 394 Other HydrocarbonsHydrogenOxygenates 512 0 512 29 18 0 47 Other HydrocarbonsHydrogen 0 0 0 28 0 0 28...
Study of the single cluster response of a helium-isobutane drift chamber prototype using 8 keV X-rays
G. Cavoto; S. Dabagov; D. Hampai; G. Piredda; F. Renga; E. Ripiccini; C. Voena
The identification of single clusters in the electronic signals produced by ionizing particles within a drift chamber is expected to significantly improve the performances of this kind of detectors in terms of particle identification capabilities and space resolution. In order to develop refined cluster recognition algorithms, it is essential to measure the response of the chamber and its electronics to single ionization clusters. This can be done by irradiating the chamber with X-rays. We report here on the studies performed on a drift chamber prototype for the MEG-II experiment at the X-ray facility of the INFN Frascati's National Laboratories "XLab Frascati". The prototype is operated with a helium-isobutane mixture and instrumented with high bandwidth custom pre-amplifiers. The results of this study have been used to develop an innovative method for cluster recognition, based on the Wiener filter technique. As a side measurement, we also performed a study of the gas gain in a configuration which is similar to that of the MEG-II experiment.
Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]
1,361 415 768 2,544 IsobutaneIsobutylene 151 4 155 99 62 164 325 Other HydrocarbonsHydrogenOxygenates 553 0 553 20 28 0 48 Other HydrocarbonsHydrogen 0 0 0 19 0 0 19...
Synthesis of octane enhancers during slurry-phase Fischer-Tropsch. Quarterly technical progress report No. 7, April 1, 1992--June 30, 1992
Marcelin, G.
The objective of this project is to investigate three possible routes to the formation of ethers, in particular methyl tert-butyl (MTBE), during slurry phase Fischer-Tropsch reaction. The three reaction schemes to be investigated are: addition of i-butylene during the formation of methanol and/or higher alcohols directly from CO and H{sub 2} during slurry-phase Fischer-Tropsch; addition of i-butylene to FT liquid products including alcohols in a slurry-phase reactor containing an MTBE or other acid catalyst; and addition of methanol to slurry phase FT synthesis making iso-olefins. During the seventh quarter we continued the shake down experiments for the SBCR and conducted an initial aborted run. We have also re-started experiments on Scheme 1, i.e., the addition of iso-butylene during CO hydrogenation. Using a dual bed arrangement, we have demonstrated the synthesis of MTBE from syngas and iso-butylene.
Synthesis of octane enhancers during slurry-phase Fischer-Tropsch
Marcelin, G.
The objective of this project is to investigate three possible routes to the formation of ethers, in particular methyl tert-butyl (MTBE), during slurry phase Fischer-Tropsch reaction. The three reaction schemes to be investigated are: addition of i-butylene during the formation of methanol and/or higher alcohols directly from CO and H[sub 2] during slurry-phase Fischer-Tropsch; addition of i-butylene to FT liquid products including alcohols in a slurry-phase reactor containing an MTBE or other acid catalyst; and addition of methanol to slurry phase FT synthesis making iso-olefins. During the seventh quarter we continued the shake down experiments for the SBCR and conducted an initial aborted run. We have also re-started experiments on Scheme 1, i.e., the addition of iso-butylene during CO hydrogenation. Using a dual bed arrangement, we have demonstrated the synthesis of MTBE from syngas and iso-butylene.
Transport of Injected Isobutane by Thermal Groundwater in Long Valley
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Etherify field butanes: Part 2
Sarathy, P.R. (John Brown, Houston, TX (United States)); Suffridge, G.S. (John Brown, Tulsa, OK (United States))
Worldwide interest in technical details concerning major components of world-scale MTBE complexes continues. Part 1 reviewed alternate scenarios for MTBE production and basic technological considerations to assess component processes for producing MTBE. Commercial technologies and cost considerations for world-scale MTBE complexes call for a focus on butane isomerization, isobutane dehydrogenation and isobutylene etherification. The paper describes isomerization; four commercial processes for dehydrogenation (Oleflex, Catofin, STAR, and FBD-4 processes); three methods for etherification (fixed bed with recycle, fixed bed tubular reactor, and catalytic distillation); and capital and production costs for the MTBE complex.
Synthesis of octane enhancers during slurry-phase Fischer-Tropsch. Quarterly technical progress report No. 8, July 1, 1992--September 30, 1992
Marcelin, G.
The initial work on the synthesis of MTBE during CO hydrogenation shows that MTBE cannot be formed directly on metal sites and likely requires the presence of an acid site. However, MTBE can be made successfully when an acid site, provided by the zeolites, is present in the vicinity of the methanol-synthesis metal sites. When i-butylene was added during CO hydrogenation over a composite catalyst consisting of Li-Pd/SiO{sub 2} and a hydrogen-zeolite, MTBE was formed in measurable amounts. The major by-product of this reaction scheme was isobutane and the dimer of i-butylene. In general, ZSM-5 was found to be superior to LZ210-12 HY zeolite. CO hydrogenation over a bifunctional PdNaY catalyst shows that branched hydrocarbons as well as MEOH can be made successfully at the same time. Addition of i-butylene over this catalyst only (i.e. without other zeolite) results in the formation of trace amounts of MTBE.
New processes to recovery methanol and remove oxygenates from Valero MTBE unit
Hillen, P.; Clemmons, J.
The refiner today has to evaluate every available option to increase octane in the gasoline pool to make up for the loss in octane created by lead phase down. Production of MTBE is one of the most attractive options. MTBE is produced by selectivity reacting isobutylene with methanol. Valero Refining's refinery at Corpus Christie, Texas (formerly Saber Refining) is one of the most modern refineries built in the last decade to upgrade resids. As part of the gasoline upgrading Valero had built a Butamer Unit to convert normal butane to isobutane upstream of their HF Alkylation Unit. In 1984 as an ongoing optimization of its operations, Valero Refining evaluated various processes to enable it to increase the octane output, and decided to build an MTBE unit. Valero selected the MTBE process licensed by Arco Technology, Inc. and contracted with Jacobs Engineering Group, Inc., Houston, Texas to provide detailed engineering and procurement services.
Selective oxidation of alkanes and/or alkenes to valuable oxygenates
Lin, Manhua (Maple Glen, PA); Pillai, Krishnan S. (North Brunwick, NJ)
A catalyst, its method of preparation and its use for producing at least one of methacrolein and methacrylic acid, for example, by subjecting isobutane or isobutylene or a mixture thereof to a vapor phase catalytic oxidation in the presence of air or oxygen. In the case where isobutane alone is subjected to a vapor phase catalytic oxidation in the presence of air or oxygen, the product is at least one of isobutylene, methacrolein and methacrylic acid. The catalyst comprises a compound having the formula A.sub.aB.sub.bX.sub.xY.sub.yZ.sub.zO.sub.o wherein A is one or more elements selected from the group of Mo, W and Zr, B is one or more elements selected from the group of Bi, Sb, Se, and Te, X is one or more elements selected from the group of Al, Bi, Ca, Ce, Co, Fe, Ga, Mg, Ni, Nb, Sn, W and Zn, Y is one or more elements selected from the group of Ag, Au, B, Cr, Cs, Cu, K, La, Li, Mg, Mn, Na, Nb, Ni, P, Pb, Rb, Re, Ru, Sn, Te, Ti, V and Zr, and Z is one or more element from the X or Y groups or from the following: As, Ba, Pd, Pt, Sr, or mixtures thereof, and wherein a=1, 0.05
Diffusion of isobutane in silicalite studied by transition path sampling Thijs J. H. Vlugta)
Dellago, Christoph
WV Amsterdam, The Netherlands Received 9 May 2000; accepted 23 August 2000 The diffusion process is important in the design of petrochemical applications.1 As both adsorption and dif- fusion experiments can- ventional molecular dynamics MD techniques cannot be used to study this process. A naive way of computing
Additives That Prevent Or Reverse Cathode Aging In Drift Chambers With Helium-Isobutane Gas
Adam Boyarski
Noise and Malter breakdown have been studied at high rates in a test chamber having the same cell structure and gas as in the BaBar drift chamber. The chamber was first damaged by exposing it to a high source level at an elevated high voltage, until its operating current at normal voltages was below 0.5nA/cm. Additives such as water or alcohol allowed the damaged chamber to operate at 25 nA/cm, but when the additive was removed the operating point reverted to the original low value. However with 0.02% to 0.05% oxygen or 5% carbon dioxide the chamber could operate at more than 25 nA/cm, and continued to operate at this level even after the additive was removed. This shows for the first time that running with an O2 or CO2 additive at high ionisation levels can cure a damaged chamber from breakdown problems.
Multivariable controller increased MTBE complex capacity
Robertson, D.; Peterson, T.J.; O`Connor, D. [DMC Corp., Houston, TX (United States); Payne, D.; Adams, V. [Valero Refining Co., Corpus Christi, TX (United States)
Capacity increased by more than 4.6% when one dynamic matrix multivariable controller began operating in Valero Refining Company`s MTBE production complex in Corpus Christi, Texas. This was on a plant that was already running well above design capacity due to previously made process changes. A single controller was developed to cover an isobutane dehydrogenation (ID) unit and an MTBE reaction and fractionation plant with the intermediate isobutylene surge drum. The overall benefit is realized by a comprehensive constrained multivariable predictive controller that properly handles all sets of limits experienced by the complex, whether limited by the front-end ID or back-end MTBE units. The controller has 20 manipulated, 6 disturbance and 44 controlled variables, and covers widely varying dynamics with settling times ranging from twenty minutes to six hours. The controller executes each minute with a six hour time horizon. A unique achievement is intelligent surge drum level handling by the controller for higher average daily complex capacity as a whole. The ID unit often operates at simultaneous limits on reactor effluent compressor capacity, cold box temperature and hydrogen/hydrocarbon ratio, and the MTBE unit at impurity in butene column overhead as well as impurity in MTBE product. The paper discusses ether production, isobutane dehydrogenation, maximizing production, controller design, and controller performance.
CarbonCarbon Bond Cleavage and Dehydrogenation of Isobutane Over HZSM-5 at Low Pressures and Temperatures
Tesfatsion, Leigh
Acidic zeolite substrates, such as HZSM-5 are vital cata- lysts in the petrochemical industry, due-temperature activation for C�C bond cleavage to propene and methane, and dehydrogenation to isobutene and hydrogen
The University of New Mexico An NSF Integrative Graduate
New Mexico, University of
, including poly(propylene fumarate) (PPF), poly (butylene fumarate) (PBF), and copolymers poly(propylene fumarate)-co-(propylene maleate) (PPFcPM) and poly(butylene fumarate)-co-(butylene maleate) (PBFcBM). We
E. In Situ Polymerization of Cyclic Butylene Terephthalate(CBT) Oligomers with Conductive fillers for Thermal Management
Harmon, Julie P.
copolymers with Thermal conductivity Composites This research is funded by Honeywell Corporation and the Florida High Tech Corridor. NOTE: Honeywell and Julie Harmon have signed an agreement with Cyclics Corp; these materials exhibit an intrinsic fiber TC as high as 913 W/mK (51). Earlier work with Honeywell focused
One multivariable controller increased capacity of an Oleflex{trademark}/MTBE complex
Robertson, D.; Peterson, T.J.; O`Connor, D. [Dynamic Matrix Control Corp., Houston, TX (United States); Adams, V.; Payne, D. [Valero Refining Co., Corpus Christi, TX (United States)
Capacity increased by more than 4.6% when one dynamic matrix controller began operating in Valero Refining Company`s MTBE production complex in Corpus Christi, Texas. This was on a plant that was already running well above design capacity due to process changes previously made on the plant. A single controller was developed to cover an Oleflex{trademark} isobutane dehydrogenation unit and an MTBe reaction and fractionation plant with the intermediate isobutylene surge drum. The overall benefit is realized by a comprehensive constrained multivariable predictive controller which properly handles all sets of limits experienced by the complex, whether limited by the front-end Oleflex{trademark} or back-end MTBE unit. The controller has 20 manipulated, 6 disturbance and 44 controlled variables, and covers widely varying dynamics with settling times ranging from twenty minutes to six hours. The controller executes each minute with a six hour time horizon. A unique achievement is intelligent handling of the surge drum level by the controller for higher average daily capacity of the complex as a whole. The Oleflex{trademark} often operates at simultaneous limits on reactor effluent compressor capacity, cold box temperature and hydrogen/hydrocarbon ratio and the MTBE at impurity in butene column overhead as well as impurity in MTBE product.
Efficient Energy Usage in Butane Splitters
Barnwell, J.; Morris, C. P.
A World surplus of mixed butanes coupled with an increased need for gasoline extenders has raised the demand for isobutane. Isobutane is readily separated from an admixture with normal butane by conventional distillation techniques. However...
Surface characterization of cross-linked elastomers by shear modulation force microscopy
Colby, Ralph H.
(isobutylene-co-4-methylstyrene) (BIMS) is a synthetic terpolymer which can be stoichiometrically cross-linked by N agreement with rubber elasticity theory was obtained in both cases. The SMFM was then used to monitor), a synthetic terpolymer of isobutylene (IB), paramethylstyrene (PMS), and parabromomethylstyrene (Br
Gasoline and Diesel Fuel Update (EIA)
combining isobutane with olefin hydrocarbons (e.g., propylene, buty- lene) through the control of temperature and pressure in the presence of an acid catalyst, usually sulfuric...
Polymer Crystallization and Precipitation-Induced Wrapping of Carbon Nanofibers with PBT
Fisher, Frank
were used to create hybrid nanostructures consisting of CNFs and poly(butylene terephthalate) (PBT Wiley Periodicals, Inc. J Appl Polym Sci 114: 1312�1319, 2009 Key words: hybrid nanostructures; carbon nanofiber; nanocomposites; crystallization; precipitation INTRODUCTION Poly (butylene terephthalate) (PBT
MTBE from butadiene-rich C/sub 4/s
Ancillotti, F.; Pescarollo, E.; Szatmari, E.; Lazar, L.
Methyl tert-butyl ether (MTBE), is made by reacting methanol with isobutylene. The preferred source of isobutylene is a steam cracker C/sub 4/ cut from which butadiene has been removed. However, moving the MTBE synthesis upstream of the butadiene extraction will improve the extraction step. The following is a review of conditions imposed on the MTBE unit's design and operation when placed in this new location.
Synthesis of octane enhancers during slurry-phase Fischer-Tropsch. Quarterly technical progress report No. 9, October 1, 1992--December 31, 1992
Marcelin, G.
Figure 7 summarizes the carbon selectivities observed towards the main products. During Period IV, the main products observed were the heavy hydrocarbons, with selectivity for MTBE being less than 3--5%. The only time that high MTBE selectivity was noted was during period III, when the i-butylene feed was shut-off. The large amounts of heavy products and the low selectivity to MTBE were surprising in view of our previous experiments in the gas phase and the high methanol-to-i-butylene ratio used in these runs. In the gas-phase and with methanol/i-butylene = 0.5, over 95% selectivity to MTBE was observed with this catalyst at this temperature. The higher level of methanol used here would be expected to further improve the MTBE selectivity. Perhaps one reason for the poor MTBE selectivity relates to the relative solubilities of the reactants in the Synfluid changing the effective methanol/i-butylene ratio. Figure 8 shows the relative molar concentration of i-butylene during Period III. At 180 minutes, the gas supply of that reactant was shut-off, yet the analyses show that i-butylene continued to elute from the reactor for at least an additional 2 hours. It seems reasonable that the i-butylene is highly soluble in the Synfluid since they are both nonpolar hydrocarbons. Likewise, one would expect the methanol to not be quite as soluble and thus the methanol/i-butylene ratio in the liquid medium may be very low, favoring the oligomerization of i-butylene. Indeed, the only time that MTBE selectivity was high was after the i-butylene supply was shut-off. We intend to quantify these solubilities in future experiments.
EFFECT OF FUEL TYPE ON FLAME IGNITION BY TRANSIENT PLASMA Jianbang Liu1,2
ABSTRACT Rise and delay times of mixtures of methane, propane, n-butane, iso-butane and iso- octane mixed performance of various fuels including methane, propane, iso-butane, n-butane and iso-octane mixed with air with air ignited by transient plasma discharge were investigated and compared with spark discharge ignition
Synthesis of MTBE during CO hydrogenation: Reaction sites required
Kazi, A.M.; Goodwin, J.G. Jr.; Marcelin, G.; Oukaci, R. [Univ. of Pittsburgh, PA (United States). Dept. of Chemical and Petroleum Engineering
Synthesis of methyl tert-butyl ether (MTBE) during carbon monoxide (CO) hydrogenation has been studied with the following reaction schemes: (1) the addition of isobutylene during CO hydrogenation over metal catalysts active for methanol synthesis (Pd/SiO{sub 2} and Li-Pd/SiO{sub 2}) and (2) the addition of isobutylene during CO hydrogenation over a dual bed configuration consisting of Li-Pd/SiO{sub 2} and a zeolite (H-ZSM-5 or HY). The addition of isobutylene during methanol synthesis over the supported Pd catalysts indicated that MTBE cannot be formed on metal sites from a reaction of isobutylene with methanol precursors. However, addition of isobutylene to the syngas feed over a dual bed consisting of a methanol synthesis catalyst and an acid zeolite downstream of the methanol synthesis catalyst showed that MTBE can be synthesized during CO hydrogenation provided acid sites are available. In order to get higher conversions of methanol to MTBE, optimization of the acid catalyst and/or reaction conditions would be required to minimize formation of byproduct hydrocarbons.
Rice Straw Fiber Reinforced High Density Polyethylene Composite: Effect of Coupled Compatibilizating and
, which are unfunctionalized ethylene/propylene copolymer (uEPR), maleic anhydride grafted EPR (EPR sty- rene/ethylene-butylenes/styrene triblock copolymer (SEBS)5,7,10�12 and ethylene/propylene
Synthesis of octane enhancer during slurry-phase Fischer-Tropsch. Quarterly technical progress report No. 4, July 1, 1991--September 30, 1991
Marcelin, G.
The objective of this project is to investigate three possible routes to the formation of ethers, in particular methyl tert-butyl ether (MTBE), during slurry phase Fischer-Tropsch reaction. The three reaction schemes to be investigated are: Addition of isobutylene during the formation of methanol and/or higher alcohols directly from CO and H{sub 2} during slurry-phase Fischer-Tropsch. Addition of isobutylene to FT liquid products including alcohols in a slurry-phase reactor containing an MTBE or other acid catalyst. Addition of methanol to slurry phase FT synthesis making iso-olefins.
Synthesis of octane enhancers during slurry-phase Fischer-Tropsch. Quarterly technical progress report No. 5, October 1, 1991--December 31, 1991
Marcelin, G.
The objective of this project is to investigate three possible routes to the formation of ethers, in particular methyl tert-butyl ether (MTBE), during slurry phase Fischer-Tropsch reaction. The three reaction schemes to be investigated are: Addition of isobutylene during the formation of methanol and/or higher alcohols directly from CO and H{sub 2} during slurry-phase Fischer-Tropsch. Addition of isobutylene to FT liquid products including alcohols in a slurry-phase reactor containing an MTBE or other acid catalyst. Addition of methanol to slurry phase FT synthesis making iso-olefins.
Synthesis of octane enhancers during slurry-phase Fischer-Tropsch. Quarterly technical progress report No. 3, April 1, 1991--June 30, 1991
Marcelin, G.
The objective of this project is to investigate three possible routes to the formation of ethers, in particular methyl tert-butytl ether (MTBE), during slurry phase Fischer-Tropsch reaction. The three reaction schemes to be investigated are: (1) Addition of isobutylene during the formation of methanol and/or higher alcohols directly from CO and H{sub 2} during slurry-phase Fischer-Tropsch; (2) addition of isobutylene to FT liquid products including alcohols in a slurry-phase reactor containing an MTBE or other acid catalyst; and, (3) addition of methanol to slurry phase FT synthesis making iso-olefins.
Measurements of the effect of a magnetic field on the transport of linear momentum in nitrogen
Larchez, Mark Edward
torgue in the same direction. A torque in the direction opposite to this is produced by methane, et'nane, propane, butane, isobutane, 7 hydrogen, nydrogen deuteride, and ceuterium, No torque is shown by helium, argon, xenon, water vapor, carbon...
Direct contact, binary fluid geothermal boiler
Rapier, Pascal M. (Richmond, CA)
Energy is extracted from geothermal brines by direct contact with a working fluid such as isobutane which is immiscible with the brine in a geothermal boiler. The geothermal boiler provides a distributor arrangement which efficiently contacts geothermal brine with the isobutane in order to prevent the entrainment of geothermal brine in the isobutane vapor which is directed to a turbine. Accordingly the problem of brine carry-over through the turbine causes corrosion and scaling thereof is eliminated. Additionally the heat exchanger includes straightening vanes for preventing startup and other temporary fluctuations in the transitional zone of the boiler from causing brine carryover into the turbine. Also a screen is provided in the heat exchanger to coalesce the working fluid and to assist in defining the location of the transitional zone where the geothermal brine and the isobutane are initially mixed.
alcohol gas additives: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Additives That Prevent Or Reverse Cathode Aging In Drift Chambers With Helium-Isobutane Gas HEP - Experiment (arXiv) Summary: Noise and Malter breakdown have been studied at high...
Recovery of methanol in an MTBE process
Whisenhunt, D.E.; Byers, G.L.; Hattiangadi, U.S.
In a process for the manufacture of methyltertiarybutylether (MTBE) in which methanol and a mixture of C/sub 4/ hydrocarbons containing isobutylene are contacted in a reaction zone containing an ion-exchange resin catalyst under suitable conditions to effect the reaction of methanol and isobutylene to produce a reaction product containing MTBE, unreacted methanol, unreacted isobutylene and other C/sub 4/ hydrocarbons, the reaction product is introduced to a fractionation zone wherein it is separated into a bottoms product comprising essentially MTBE and an overhead product containing unreacted methanol, unreacted isobutylene, and other C/sub 4/ hydrocarbons, and the overhead product is introduced to an absorption zone wherein the methanol is absorbed; the improvement is described which comprises utilizing silica gel as adsorbent and regenerating the silica gel adsorbent in a closed loop by contacting the silica gel absorbent with a desorption gas stream at an elevated temperature for a sufficient period of time to remove absorbed methanol, cooling the effluent from the adsorption zone to condense desorbed methanol removing desorbed methanol from the system and recycling the desorption gas to the adsorption zone.
Conversion of methane and acetylene into gasoline range hydrocarbons
Alkhawaldeh, Ammar
Conversion Apparatus. . . 20 22 Temperature Profile Inside the Reactor. . 30 Methane and Acetylene Conversion over Time on Stream, T = 412 C, Molar Feed Ratio = 6/I (CH4/CqHr). . 36 Mass Flow Rate (g/s) of the Effluent Gas (Unreacted Methane... and Acetylene, Isobutane, Ethylene, and Nitrogen) from the Reactor Integrated over Time on Stream. 40 Mass Flow Rate (g/s) of the Gas Products (Isobutane and Ethylene) Integrated over Time on Stream. 41 Methane and Acetylene Conversion over Time on Stream...
Synthesis of octane enhancers during slurry-phase Fischer-Tropsch. Quarterly technical progress report No. 6, January 1, 1992--March 31, 1992
Marcelin, G.
The objective of this project is to investigate three possible routes to the formation of ethers, in particular methyl tert-butyl ether (MTBE), during slurry phase Fischer-Tropsch reaction. The three reaction schemes to be investigated are: (1) Addition of isobutylene during the formation of methanol and/or higher alcohols directly from CO and H{sub 2} during slurry-phase Fischer-Tropsch. (2) Addition of isobutylene to FT liquid products including alcohols in a slurry-phase reactor containing an MTBE or other acid catalyst. (3) Addition of methanol to slurry phase FT synthesis making iso-olefins. During the sixth quarter we completed the construction of the slurry bubble column reactor (SBCR), conducted initial shake-down experiments in a cold-flow mode, and finalized the selection process of the acid catalysts for conversion of syngas-produced alcohols and isobutylene to MTBE (scheme 2). Tasks 3, 4, and 5 are awaiting complete implementation of the SBCR system.
Synthesis of octane enhancers during slurry-phase Fischer-Tropsch. [801Methyl tert-butyl ether
Marcelin, G.
The objective of this project is to investigate three possible routes to the formation of ethers, in particular methyl tert-butyl ether (MTBE), during slurry phase Fischer-Tropsch reaction. The three reaction schemes to be investigated are: (1) Addition of isobutylene during the formation of methanol and/or higher alcohols directly from CO and H{sub 2} during slurry-phase Fischer-Tropsch. (2) Addition of isobutylene to FT liquid products including alcohols in a slurry-phase reactor containing an MTBE or other acid catalyst. (3) Addition of methanol to slurry phase FT synthesis making iso-olefins. During the sixth quarter we completed the construction of the slurry bubble column reactor (SBCR), conducted initial shake-down experiments in a cold-flow mode, and finalized the selection process of the acid catalysts for conversion of syngas-produced alcohols and isobutylene to MTBE (scheme 2). Tasks 3, 4, and 5 are awaiting complete implementation of the SBCR system.
Catalytic oxidation of light alkanes in presence of a base
Bhinde, Manoj V. (Boothwyn, PA); Bierl, Thomas W. (West Chester, PA)
The presence of a base in the reaction mixture in a metal-ligand catalyzed partial oxidation of alkanes results in sustained catalyst activity, and in greater percent conversion as compared with oxidation in the absence of base, while maintaining satisfactory selectivity for the desired oxidation, for example the oxidation of isobutane to isobutanol.
Catalytic oxidation of light alkanes in presence of a base
Bhinde, M.V.; Bierl, T.W.
The presence of a base in the reaction mixture in a metal-ligand catalyzed partial oxidation of alkanes results in sustained catalyst activity, and in greater percent conversion as compared with oxidation in the absence of base, while maintaining satisfactory selectivity for the desired oxidation, for example the oxidation of isobutane to isobutanol. 1 fig.
Llope, William J.
North Platform to Vent Plastic tubing FM2 FM3FM1 Freon R134A 63ccm, 125lb SF6 0-3.5ccm, 56lb Isobutane 3.5ccm, 10lb w/ Heat Blanket STAR Gas Pad (outdoors) STAR Gas Mixing Room Legend MV PI FM CV MSV Manual
Paris-Sud XI, Universit� de
67 MOBILITIES OF POSITIVE IONS IN SOME GAS MIXTURES USED IN PROPORTIONAL AND DRIFT CHAMBERS G proportional chambers or drift chambers with gas mixtures, using isobutane as a quencher. The positive ions, r�vis� le 11 juin 1976, accept� le 2 septembre 1976) R�sum�. 2014 Le coefficient de mobilit� des ions
A high-resolution drift chamber for Alpha-particle position measurements
Oliver, Jon Patrick
A drift chamber module with 5 anode wires covering an active region of 9 cm x 76 cm has been built to locate the vertical position of a-particle trajectories to within 295 mm full-width-half-maximum (FWEM) in isobutane at a pressure of 0.25 atm...
Improving the Carbon Dioxide Emission Estimates from the Combustion of Fossil Fuels in California
de la Rue du Can, Stephane
Gas, Crude Oil and Distillates NGLs consumption in CALEBConsumption Weekly Refinery and Fractionator Report Weekly Bulk Terminal Report Weekly Product Pipeline Report Weekly Crude OilCrude Oil Butane Isobutane Other Hydrocarbons, Hydrogen and Oxygenates 10,718 Unfinished Oils Source: CEC 2006a The energy sector shows the consumption
Roaming radical pathways for the decomposition of alkanes.
Harding, L. B.; Klippenstein, S. J. (Chemical Sciences and Engineering Division)
CASPT2 calculations predict the existence of roaming radical pathways for the decomposition of propane, n-butane, isobutane and neopentane. The roaming radical paths lead to the formation of an alkane and an alkene instead of the expected radical products. The predicted barriers for the roaming radical paths lie {approx}1 kcal/mol below the corresponding radical asymptotes.
Atmospheric budget of acetone Daniel J. Jacob, Brendan D. Field, Emily M. Jin, Isabelle Bey, Qinbin Li,
Li, Qinbin
and distribution of acetone are investigated by using a priori estimates of sources and sinks to constrain a global isoalkanes (propane, isobutane, isopentane). Model simulation of isoalkanes and comparison to observations yields best global emission estimates of 12 Tg C yr�1 for propane (including only 0.6 Tg C yr�1 from
Hydrocarbon Processing`s HPI construction boxscore update
Data are compiled for oil and gas industry construction projects worldwide, listing country (and state or province, when appropriate), company, location of the project, purpose, plant capacity, estimated cost, current status, licensor, engineering firm, and construction company. Projects include carbon monoxide, urea, ammonia, isomerizer, hydrogen, alkylation, TAME, desalter, hydrotreating, sulfur, waste gas cleanup, catalytic reformer, ethylene recovery, natural gas helium, nitrogen removal, NGL recovery, cumene, dewaxer, polystyrene, vinyl chloride, synthesis gas, formaldehyde, FCC cracker, isobutylene, H{sub 2}S removal, cogeneration, methanol, delayed coker, gas oil treater, NGL fractionation, BTX, information systems, control systems, waste water cleanup, glycol treater, acid gas removal, LPG, MTBE, caustic cleanup, visbreaker, naphtha treater, and others.
MTBE will be a boon to U. S. gas processors
Otto, K.W. (Purvin and Gertz, Inc. Dallas, TX (United States))
This paper reports that the advent of methyl tertiary butyl ether (MTBE) as the primary oxygenate blending component for oxygenated and reformulated motor fuels promises significant benefits for the U.S. gas-processing industry. Increased demand for isobutane as MTBE-plant feedstock will buoy both normal butane and isobutane pricing in U.S. gulf Coast during the 1990s. Elimination of the need to crack normal butane in U.S. olefin plants will also strengthen competitive feedstocks somewhat, including ethane and propane. And increased use of normal butane as isomerization feedstock will result in wider recognition of the premium quality of gas plant normal butane production compared to most refinery C[sub 4] production.
Effect of lower feedstock prices on economics of MTBE complex
Rahman, F.; Hamid, S.H.; Ali, M.A. [King Fahd Univ. of Petroleum and Minerals, Dhahran (Saudi Arabia)
Economic evaluation of the methyl tertiary butyl ether (MTBE) complex was carried out starting from n-butane and by captive production of methanol from natural gas. The processing steps consist of isomerization of n-butane to isobutane, dehydrogenation of isobutane to make isobutene, and finally, the reaction of isobutene with methanol to produce MTBE. Two different plant sizes were considered, and the effect of 30% lower feedback prices on profitability was studied. It was found that the raw materials cost is a dominant component, composing about 55% of the total production cost. An internal rate of return of 19% could be realized for 500,000 tons per annum MTBE complex based on economic data in mid-1993. The payback period estimated at this capacity was 3.8 years, and the break-even capacity was 36.6%.
Chem 115Lithium-Halogen ExchangeMyers RLi + R'X RX + R'Li
Chem 115Lithium-Halogen ExchangeMyers RLi + R'X RX + R'Li Lithium-halogen exchange reactions are essentially inert. 2 t-BuLi t-BuI + RLi t-BuLi isobutene + isobutane + LiI Lithium-halogen exchange reactions, and lithium iodide. H OEtBr H H OEtLi H1.1 eq n-BuLi Et2O, !80 �C Lau, K. S.; Schlosser, M. J. Org. Chem. 1978
PROPRIETARY MATERIAL. 2011 The McGraw-Hill Companies, Inc. Limited distribution permitted only to teachers and educators for course preparation. If you are a student using this Manual, you are using it without permission.
Bahrami, Majid
from the steam turbine and the binary cycle, and the thermal efficiencies for the binary cycle from the steam turbine and the binary cycle are kW15,410 kJ/kg)7.23448.1kJ/kg)(27438.19()( 433steamT,binarynet, 98isoT, inp iso wmWW hhmW steam turbine production well reinjection well isobutane turbine heat
The MTBE solution: Octanes, technology, and refinery profitability
Lander, E.P.; Hubbard, J.N.; Smith, L.A.
This paper has been developed to provide refiners with business decision insight regarding the production of methyl tertiary butyl ether (MTBE) from refinery - (FCC) produced isobutylene. The driving forces making MTBE an attractive investment are examined with regard to the increasing demand for higher octane unleaded gasolines. The decision to proceed with MTBE production depends on the profitability of such an investment and the refiner's ability to meet market demands using available processing equipment, refinery produced streams and external feedstocks. The factors affecting this decision are analyzed in this paper and include: industry ability to meet rising octane demand; profit potential realized by diverting isobutylene to MTBE; availability of technology for producing MTBE; and investment and operating costs required to produce MTBE. Chemical Research and Licensing and NEOCHEM have developed a simple, low cost process to produce MTBE, reducing the excessive equipment and high operating costs that were associated with conventional MTBE designs. The economics and process benefits of installing a CRandL/NEOCHEM MTBE process are examined within the framework of a generalized medium-sized refinery configuration.
New binding materials for metal hydride electrodes which permit good recyclability
Hara, T.; Yasuda, N. (Japan Synthetic Rubber Co., Ltd., Yokkaichi (Japan). Development Center); Takeuchi, Y. (Japan Synthetic Rubber Co., Ltd., Tokyo (Japan). Electronics Project Dept.); Sakai, T.; Uchiyama, A.; Miyamura, H.; Kuriyama, N.; Ishikawa, H. (Government Industrial Research Inst., Osaka (Japan))
Thermoplastic elastomers such as styrene-butadiene-styrene block copolymer (SBS) and styrene-ethylene/butylene-styrene block copolymer (SEBS) were used successfully as binding materials for metal hydride (MH) electrodes of a nickel-metal hydride battery. These binding materials have a rubber-like nature and are soluble in organic solvents. It was easy to remove the alloy powder from a used electrode for recycling. The battery performance depended on both the kind and amount of binding materials. The best discharge capacity and rate capability were obtained for MH electrodes containing 2--5 weight percent (w/o) SEBS. The particle size distributions for the alloy were examined successfully.
Figure A1 Time-series of N1 fan speed (% of maximum) and exhaust gas temperature for experiments conducted (a) 4% load, (b) 7% (c) 30% and (d) 85% engine loads. Warm-up and
Meskhidze, Nicholas
Hydrogen Wt % 14.0 D3701 Aromatics Vol % 14.1 D1319 Olefins Vol % 1.4 D1319 Saturates Vol % 84.5 D1319). a Not detected. SOAM II compound class Precursor species 4% (mg kg fuel-1 ) 85% (mg kg fuel-1 ) propane 37.4 32.6 isobutane 42.7 42.2 butane 24.8 29.2 isopentane 34.0 29.9 pentane 12.0 15.6 cyclopentane 12.6 1.8 2
Coke profile and effect on methane/ethylene conversion process
Al-Solami, Bandar
with distance along the reactor, and therefore the coke distribution should follow a similar pattern. A distribution of coke deposits along the reactor was also observed by Noda er al. (1974) in a study of iso-pentane isomerization. In this case the coke..., methane, ethane, ethylene, propane, iso-butane, butane, iso-pentane, pentane and hexanes. Also, the flow rate of the effluent stream is measured using the bubble meter. The mole percentages of methane and ethylene are subtracted of the effluent stream...
Crystalline mesoporous zirconia catalysts having stable tetragonal pore wall structure
Sachtler, W.M.H.; Huang, Y.Y.
Methods are disclosed for the preparation of new sulfated mesoporous zirconia materials/catalysts with crystalline pore walls of predominantly tetragonal crystal structure, characterized by nitrogen physical sorption measurement, X-ray diffraction, transmission electron microscopy and catalytic tests using n-butane isomerization to iso-butane and alkylation of 1-naphthol with 4-tert-butylstyrene as probe reactions. Sulfate deposition is preferred for the transformation of a mesoporous precursor with amorphous pore walls into a material with crystalline pore walls maintaining the mesoporous characteristics. 17 figs.
Crystalline mesoporous zirconia catalysts having stable tetragonal pore wall structure
Sachtler, Wolfgang M. H. (Evanston, IL); Huang, Yin-Yan (Evanston, IL)
Methods for the preparation of new sulfated mesoporous zirconia materials/catalysts with crystalline pore walls of predominantly tetragonal crystal structure, characterized by nitrogen physisorption measurement, X-ray diffraction, transmission electron microscopy and catalytic tests using n-butane isomerization to iso-butane and alkylation of 1-naphthol with 4-tert-butylstyrene as probe reactions. Sulfate deposition is preferred for the transformation of a mesoporous precursor with amorphous pore walls into a material with crystalline pore walls maintaining the mesoporous characteristics.
Catalyst Activity Comparison of Alcohols over Zeolites
Ramasamy, Karthikeyan K.; Wang, Yong
Alcohol transformation to transportation fuel range hydrocarbon on HZSM-5 (SiO2 / Al2O3 = 30) catalyst was studied at 360oC and 300psig. Product distributions and catalyst life were compared using methanol, ethanol, 1-propanol or 1-butanol as a feed. The catalyst life for 1-propanol and 1-butanol was more than double compared to that for methanol and ethanol. For all the alcohols studied, the product distributions (classified to paraffin, olefin, napthene, aromatic and naphthalene compounds) varied with time on stream (TOS). At 24 hours TOS, liquid product from 1-propanol and 1-butanol transformation primarily contains higher olefin compounds. The alcohol transformation process to higher hydrocarbon involves a complex set of reaction pathways such as dehydration, oligomerization, dehydrocyclization, and hydrogenation. Compared to ethylene generated from methanol and ethanol, oligomerization of propylene and butylene has a lower activation energy and can readily take place on weaker acidic sites. On the other hand, dehydrocyclization of propylene and butylene to form the cyclic compounds requires the sits with stronger acid strength. Combination of the above mentioned reasons are the primary reasons for olefin rich product generated in the later stage of the time on stream and for the extended catalyst life time for 1 propanol and 1 butanol compared to methanol and ethanol conversion over HZSM-5.
Economics for iso-olefin production using the fluid catalytic cracking unit
McClung, R.G.; Witoshkin, A.; Bogert, D.C.; Winkler, W.S. [Englehard Corp., Iselin, NJ (United States)
The Clean Air Act of 1990 requires use of oxygenates in some gasolines to improve both CO and hydrocarbon auto tailpipe emissions. Various oxygenates are currently being used by the refining industry. For the fully integrated refinery having a fluid catalytic cracking unit, the most commonly used oxygenates are methyl tertiary butyl ether (MTBE) and tertiary amyl ether (TAME). The FCC unit produces the isobutylene and iso-amylases need for manufacture of both MTBE and TAME. The economics for an assumed refinery processing scheme for several FCC cases are examined giving estimates of income and investments for each case. Up to one-third of the total gasoline pool can be made in reformulated gasoline using TAME and MTBE with the FCC unit as the sole source of feedstock. This processing route is much more economical than the alternative scheme using butane isomerization/iosbutane dehydrogenation.
Oligomerize for better gasoline
Nierlich, F. (Huls AG, Marl (DE))
This paper reports on normal butene containing isobutene-depleted C{sub 4} hydrocarbons like raffinate II which are oligomerized using the Octol process in the liquid phase on a heterogeneous catalyst system to yield mainly C{sub 8} and C{sub 12} olefins. Raffinate II, the spent C{sub 4} fraction of an MTBE unit, is an ideal feedstock for further n-butene processing because of its high olefin concentration ranging between 70% and 80%. By modifications of MTBE technology, implementation of selective hydrogenation for removal of residual butadiene and superfractionating raffinate II, polymer grade 1-butene can be produced. Until the mid-70s raffinate I, the team cracker C{sub 4} cut after butadiene extraction, was mainly burned or blended into gasoline. Now nearly all raffinate I is or will be consumed for the purpose of converting isobutylene to MTBE.
IsoTex: Texaco`s olefin skeletal isomerization process
Sawicki, R.A.; Pellet, R.J.; Kuhlmann, E.J.; Huang, H.M.; O`Young, C.L.; Kessler, R.V.; Casey, D.G. [Texaco Research and Development, Beacon, NY (United States)
Texaco has developed a new process (IsoTex) for the skeletal isomerization of n-olefins. The IsoTex process can convert normal butenes to isobutylene or normal pentenes to isoamylenes. The resulting product stream is an excellent feed for MTBE, ETBE or TAME units. The process has isomerized an untreated refinery C4 raffinate stream from an MTBE plant. A kinetic model was developed for the butene system. This model accurately predicted IsoTex performance in a one barrel per day skid unit at a Gulf Coast chemical plant. Process economics have been calculated for a once through 54,000 BPD C{sub 4} isomerization plant as well as a 10,000 BPD plant for recycle to an existing MTBE reactor. Economics have also been completed for a 6,800 BPD pentene once through isomerization unit.
Equilibrium thermodynamic analysis of liquid-phase ethyl tert-butylether (ETBE) synthesis
Jensen, K.L.; Datta, R. [Univ. of Iowa, Iowa City, IA (United States)
Methyl tertiary butyl ether (MTBE) is now the second largest volume organic chemical, only behind ethylene, produced in the U.S. This is remarkable since its commercial production began barely two decades ago. Although MTBE is currently the industry standard, it has been proposed that ethanol and other renewable additives make up to 30% of the oxygenate market. As a result, ethyl tertiary butyl ether (ETBE, or 2-ethyoxy 2-methyl propane), derived from renewable ethanol and isobutylene, has emerged as a promising new oxygenate. ETBE also has a somewhat lower blending Reid vapor pressure as well as a higher octane number than MTBE. This paper describes the thermodynamic equilibrium constant for the production of ETBE.
Liquid-solid phase diagrams of binary carbonates for lithium batteries
Ding, M.S.; Xu, K.; Jow, T.R.
The authors present the liquid-solid phase diagrams that they mapped with a differential scanning calorimeter (DSC) for the following seven binary carbonates: dimethyl carbonate (DMC)-ethylene carbonate (EC), ethyl methyl carbonate (EMC)-EC, EMC-propylene carbonate (PC), EMC-dimethyl ethylene carbonate (DMEC), EMC-isobutylene carbonate (iBC), PC-EC, and EMC-DMC. Many of these are among the most frequently used solvent systems for making the nonaqueous electrolytes for lithium batteries. The phase diagrams of these carbonate systems are all of the simple eutectic type but with vastly different particular features. Comparison of these phase diagrams shows that to expand the liquid region of a carbonate system toward low temperature, the two components of the system need to have comparable melting temperatures and compatible molecular structures. These results are consistent with thermodynamic considerations and have significant practical implications.
Assessment of ether and alcohol fuels from coal. Volume 2. Technical report
Not Available
A unique route for the indirect liquefaction of coal to produce transportation fuel has been evaluated. The resultant fuel includes alkyl tertiary alkyl ethers and higher alcohols, all in the gasoline boiling range. When blended into gasoline, the ether fuel provides several advantages over the lower alcohols: (1) lower chemical oxygen content, (2) less-severe water-separation problems, and (3) reduced front-end volatility effects. The ether fuel also has high-octane quality. Further, it can be utilized as a gasoline substitute in all proportions. Production of ether fuel combines several steps, all of which are or have been practiced on an industrial scale: (1) coal gasification, (2) gas cleanup and shift to desired H/sub 2/:CO ratio, (3) conversion of synthesis gas to isobutanol, methanol, and higher alcohols, (4) separation of alcohols, (5) chemical dehydration of isobutanol to isobutylene, and (6) etherification of isobutylene with methanol. A pilot-plant investigation of the isobutanol synthesis step was performed. Estimates of ether-fuel manufacturing costs indicate this process route is significantly more costly than synthesis of methanol. However, the fuel performance features provide incentive for developing the necessary process and catalyst improvements. Co-production of higher-molecular-weight co-solvent alcohols represents a less-drastic form of methanol modification to achieve improvement in the performance of methanol-gasoline blends. Costs were estimated for producing several proportions of methanol plus higher alcohols from coal. Estimated fuel selling price increases regularly but modestly with higher alcohol content.
Performance of a new LMRPC prototype for the STAR MTD system
Ruan, L.J.; Wang, Y.; Chen, H. S.; Ding, W. C.; Qiu, X. Z.; Wang, J. B.; Zhu, X. L.; Kang, K. J.; Cheng, J. P.; Li, Y. J.; Ruan, L.; Xu, Z.; Asselta, K.; Christie, W.; D'Agostino, C.; Dunlop, J.; Landgraf, J.; Ljubicic, T.; Scheblein, J.; Soja, R.; Tang, A. H.; Ullrich, T.; Crawford, H. J.; Engelage, J.; Sanchez, M. Calderon de la Barca; Reed, R.; Liu, H. D.; Butterworth, J.; Eppley, G.; Geurts, F.; Llope, W. J.; McDonald, D.; Nussbaum, T.; Roberts, J.; Xin, K.; Bridges, L.; Li, J. C.; Qian, S.; Ning, Z.; Chen, H. F.; Huang, B. C.; Li, C.; Shao, M.; Sun, Y. J.; Tang, Z. B.; Wang, X. L.; Xu, Y. C.; Zhang, Z. P.; Zeng, H.; Zhou, Y.; Clarke, R.; Mioduszewski, S.; Davila, A.; Hoffmann, G. W.; Li, L.; Markert, C.; Ray, L.; Schambach, J.; Thein, D.; Wada, M.; Ahammed, Z.; Bhaduri, P. P.; Chattopadhyay, S.; Dubey, A. K.; Dutt-Mazumdar, M. R.; Ghosh, P.; Khan, S. A.; Muhuri, S.; Mohanty, B.; Nayak, T. K.; Pal, S.; Singaraju, R.; Singhal, V.; Tribedy, P.; Viyogi, Y. P.
A new prototype of a Long-Strip Multi-Gap Resistive Plate Chamber (LMRPC) for the STAR Muon Telescope Detector (MTD) at RHIC has been developed. This prototype has an active area of 52 x 90 cm{sup 2} and consists of six 250 {mu}m wide gaps. Each detector has 12 strips, read-out at both ends, which are each 3.8 cm wide and 90 cm long with 0.6 cm intervals. In cosmic-ray tests, the efficiency was larger than 95% and the time resolution was {approx}75 ps for the 94% Freon, 5% iso-butane, and 1% SF{sub 6} gas mixture. There was good uniformity in the performance across the different strips. The module was also tested in a proton beam at IHEP in Beijing. The efficiency was close to 100% and the best timing resolution achieved was 55 ps for the 90% Freon, 5% iso-butane, and 5% SF6 gas mixture. Trigger scans along and across the strip direction were also performed.
Catalytic conversion of light alkanes - phase V. Topical report, February 1993--October 1994
We have made excellent progress toward a practical route from field butanes to MTBE, the oxygenate of choice for high-octane, clean-burning, environmentally acceptable reformulated gasoline. We have evaluated two proprietary process possibilities with a potential commercial partner and have conducted a joint catalyst evaluation program. The first of the two potential processes considered during the past quarter utilizes a two-step route from isobutane to tert-butyl alcohol, TBA. Not only is TBA an intermediate for MTBE production but is equally applicable for ETBE-an oxygenate which utilizes renewable ethanol in its` manufacture. In the two-step process, isobutane is oxidized in a non-catalytic reaction to a roughly equal mixture of TBA and tert-butyl hydroperoxide. TBHP, eq. 1. We have developed an inexpensive new catalyst system based on an electron-deficient macrocyclic metal complex that selectively converts TBHP to TBA, eq. 2, and meets or exceeds all of the process criteria that we have set.
Economic evaluation of four types of dry/wet cooling applied to the 5-MWe Raft River geothermal power plant
Bamberger, J.A.; Allemann, R.T.
A cost study is described which compared the economics of four dry/wet cooling systems to use at the existing Raft River Geothermal Plant. The results apply only at this site and should not be generalized without due consideration of the complete geothermal cycle. These systems are: the Binary Cooling Tower, evaporative condenser, Combin-aire, and a metal fin-tube dry cooling tower with deluge augmentation. The systems were evaluated using cooled, treated geothermal fluid instead of ground or surface water in the cooling loops. All comparisons were performed on the basis of a common plant site - the Raft River 5 MWe geothermal plant in Idaho. The Binary Cooling Tower and the Combin-aire cooling system were designed assuming the use of the isobutane/water surface condenser currently installed at the Raft River Plant. The other two systems had the isobutane ducted to the evaporative condensers. Capital credit was not given to the system employing the direct condensing process. The cost of the systems were estimated from designs provided by the vendors. The levelized energy cost range for each cooling system is listed below. The levelized energy cost reflects the incremental cost of the cooling system for the life of the plant. The estimates are presented in 1981 dollars.
Mechanism of olefin production on Pt, Rh, and Pd catalysts
Huff, M.; Schmidt, L.D. [Univ. of Minnesota, Minneapolis, MN (United States)
The partial oxidation of ethylene, propylene, and butylene in an autothermal reactor at atmospheric pressure with contact times less that {approximately}10 milliseconds leads to high selectivities to mono-olefins over Pt/Al{sub 2}O{sub 3}, synthesis gas over Rh/Al{sub 2}O{sub 3}, and rapid carbon deposition and deactivation over Pd/Al{sub 2}O{sub 3} at complete oxygen conversion and high alkane conversion. In all cases, thermodynamics predicts carbon deposition. We will show how the product distributions vary with choice of catalyst and reaction conditions. We will use an elementary step model based on surface reaction rates on the various metals obtained from the surface science literature to simulate these experimental results. The dominant reaction pathways on the different metals can be explained by the relative preference for {beta} elimination reactions on Pt, nearly even split between {alpha} and {beta} elimination on Rh, and rapid {alpha} elimination on Pd.
Comparison of precursor infiltration into polymer thin films via atomic layer deposition and sequential vapor infiltration using in-situ quartz crystal microgravimetry
Padbury, Richard P.; Jur, Jesse S., E-mail: firstname.lastname@example.com [Department of Textile Engineering, Chemistry and Science, North Carolina State University, Raleigh, North Carolina 27695 (United States)
Previous research exploring inorganic materials nucleation behavior on polymers via atomic layer deposition indicates the formation of hybrid organic�inorganic materials that form within the subsurface of the polymer. This has inspired adaptations to the process, such as sequential vapor infiltration, which enhances the diffusion of organometallic precursors into the subsurface of the polymer to promote the formation of a hybrid organic�inorganic coating. This work highlights the fundamental difference in mass uptake behavior between atomic layer deposition and sequential vapor infiltration using in-situ methods. In particular, in-situ quartz crystal microgravimetry is used to compare the mass uptake behavior of trimethyl aluminum in poly(butylene terephthalate) and polyamide-6 polymer thin films. The importance of trimethyl aluminum diffusion into the polymer subsurface and the subsequent chemical reactions with polymer functional groups are discussed.
Texas plant will use new process to coproduce propylene oxide, MTBE
Rhodes, A.K.
Texaco Chemical Co. is building a $400 + million facility to produce 1.2 billion lb/year (14,000 b/d) methyl tertiary butyl ether (MTBE) and 400 million lb/year (about 500 metric tons/day) propylene oxide (PO). The facility-under construction at Port Neches, Tex.-will utilize a newly developed Texaco process that coproduces the two chemicals. The process produces propylene oxide and tertiary butyl alcohol (TBA) from the reaction of isobutane with oxygen in one step, then in a second step with propylene. The TBA is then reacted with methanol in a one-step process that synthesizes MTBE. The paper describes the Port Neches facilities, construction schedule, feedstocks, product uses, and auxiliary equipment.
Ignition and extinction in the catalytic oxidation of hydrocarbons over platinum
Veser, G.; Schmidt, L.D. [Univ. of Minnesota, Minneapolis, MN (United States). Dept. of Chemical Engineering and Materials Science] [Univ. of Minnesota, Minneapolis, MN (United States). Dept. of Chemical Engineering and Materials Science
The ignition-extinction behavior in the oxidation of methane, ethane, propane and isobutane, as well as of ethylene and propylene over a platinum-foil catalyst was studied over the entire range of fuel/air ratios at atmospheric pressure. Ignition and extinction of the heterogeneous surface reaction, homogeneous ignition and the autothermal behavior of these fuel-air mixtures were investigated. The results show a common trend in the ignition extinction behavior of the alkanes and a different trend for the olefins. This is discussed in terms of a simple model, which correctly predicts the composition dependence of the surface ignition curve for reasonable values of parameters, indicating a mainly oxygen-covered surface during ignition of the alkanes and a mainly hydrocarbon-covered surface in the case of the olefins. Different branches of the complete bifurcation diagrams are discussed separately, allowing qualitative conclusions about the catalytic activity of Pt for the oxidation reactions of different fuels.
Performances of linseed oil-free bakelite RPC prototypes with cosmic ray muons
S. Biswas; S. Bhattacharya; S. Bose; S. Chattopadhyay; S. Saha; M. K. Sharan; Y. P. Viyogi
A comparative study has been performed on Resistive Plate Chambers (RPC) made of two different grades of bakelite paper laminates, produced and commercially available in India. The chambers, operated in the streamer mode using argon, tetrafluroethane and isobutane in 34:59:7 mixing ratio, are tested for the efficiency and the stability with cosmic rays. A particular grade of bakelite (P-120, NEMA LI-1989 Grade XXX), used for high voltage insulation in humid conditions, was found to give satisfactory performance with stable efficiency of > 96% continuously for more than 130 days. A thin coating of silicone fluid on the inner surfaces of the bakelite RPC is found to be necessary for operation of the detector.
Simple electronic apparatus for the analysis of radioactively labeled gel electrophoretograms
Goulianos, Konstantin (New York, NY); Smith, Karen K. (New York, NY); White, Sebastian N. (New York, NY)
A high resolution position sensitive radiation detector for analyzing radiation emanating from a source, constructed of a thin plate having an elongated slot with conductive edges acting as a cathode, a charged anode wire positioned within 0.5 mm adjacent the source and running parallel to the slot and centered therein, an ionizable gas ionized by radiation emanating from the source provided surrounding the anode wire in the slot, a helical wire induction coil serving as a delay line and positioned beneath the anode wire for detecting gas ionization and for producing resulting ionization signals, and processing circuits coupled to the induction coil for receiving ionization signals induced therein after determining therefrom the location along the anode wire of any radiation emanating from the source. An ionization gas of 70% Ar, 29% Isobutane, 0.6% Freon 13BI, and 0.4% Methylal is used.
Field tests of a vertical-fluted-tube condenser in the prototype power plant at the Raft River Geothermal Test Site
Murphy, R.W.
A vertical-fluted-tube condenser was designed, fabricated, and tested with isobutane as the shell-side working fluid in a binary prototype power plant at the Raft River Geothermal Test Site. After shakedown and contamination removal operations were completed, the four-pass water-cooled unit (with 102 outside-fluted Admiralty tubes) achieved performance predictions while operating with the plant surface evaporator on-line. A sample comparison shows that use of this enhanced condenser concept offers the potential for a reduction of about 65% from the size suggested by corresponding designs using conventional horizontal-smooth-tube concepts. Subsequent substitution of a direct-contact evaporator for the surface evaporator brought drastic reductions in system performance, the apparent consequence of high concentrations of noncondensible gases introduced by the brine/working-fluid interaction.
DME-to-oxygenates process studies
Tartamella, T.L.; Sardesai, A.; Lee, S. [Univ. of Akron, OH (United States); Kulik, C.J. [Electric Power Research Inst., Palo Alto, CA (United States)
The feasibility of the production of hydrocarbons from dimethyl ether (DNM) has been illustrated in a fixed bed micro-reactor as well as a bench scale fluidized bed reactor by the University of Akron/EPRI DME-to-Hydrocarbon (DTG) Process. The DTG process has distinct advantages over its methanol based counterpart. Specifically, the DTG process excels in the area of higher productivity, higher per-pass conversion, and lower heat duties than the MTG process. Also of special importance is the production of oxygenates -- including MTBE, ETBE, and TAME. DME may be reacted with isobutylene to produce a mixture of MTBE and ETBE. The properties of ETBE excel over MTBE in the areas of lower RVP and higher RON. According to industrial reports, MTBE is the fastest growing chemical (1992 US capacity 135,350 BPD, with expected growth of 34%/year to 1997). Also, recent renewed interest as an octane-enhancer and as a source of oxygen has spurred a growing interest in nonrefinery synthesis routes to ETBE. TAME, with its lower RVP and higher RON has proven useful as a gasoline blending agent and octane enhancer and may also be produced directly from DME. DME, therefore, serves as a valuable feedstock in the conversion of may oxygenates with wide-scale industrial importance. It should be also noted that the interest in the utilization of DME as process feedstock is based on the favorable process economics of EPRI/UA`s liquid phase DME process.
Use TAME and heavier ethers to improve gasoline properties
Ignatius, J.; Jaervelin, H.; Lindqvist, P. (Neste Engineering, Porvoo (Finland))
Producing oxygenates from all potential FCC tertiary olefins is one of the most economic methods for reducing olefins and Reid vapor pressure (Rvp) in motor gasoline. MTBE production based on FCC isobutylene has reached a very high level. But the amount of MTBE from a refinery sidestream MTBE unit is insufficient for producing reformulated gasoline (RFG) and additional oxygenates must be purchased. The next phase will see conversion of isoamylenes in FCC light gasoline to TAME. Very little attention has been given to the heavier tertiary olefins present in the FCC light gasoline like tert-hexenes and heptenes. This route allows higher levels of oxygenates production, thereby lowering Rvp and the proportion of olefins in the gasoline pool and maximizing the use of FCC olefins. By using all the components produced by an FCC efficiently, many gasoline problems can be solved. Isobutene is converted to MTBE, C[sub 3]/C[sub 4] olefins are converted to alkylate and C[sub 5] tertiary olefins can be converted to TAME. All of these are preferred components for gasoline quality. By producing more oxygenates like MTBE, TAME and heavier ethers, a refinery can be self-sufficient in blending reformulated gasoline and no oxygenates need to be purchased. The technology for producing TAME and other ethers is described.
Solvation and Acid Strength Effects on Catalysis by Faujasite Zeolites
Gounder, Rajamani P.; Jones, Andrew J.; Carr, Robert T.; Iglesia, Enrique
Kinetic, spectroscopic, and chemical titration data indicate that differences in monomolecular isobutane cracking and dehydrogenation and methanol dehydration turnover rates (per H+) among FAU zeolites treated thermally with steam (H-USY) and then chemically with ammonium hexafluorosilicate (CDHUSY) predominantly reflect differences in the size and solvating properties of their supercage voids rather than differences in acid strength. The number of protons on a given sample was measured consistently by titrations with Na+, with CH3 groups via reactions of dimethyl ether, and with 2,6-di-tert-butylpyridine during methanol dehydration catalysis; these titration values were also supported by commensurate changes in acidic OH infrared band areas upon exposure to titrant molecules. The number of protons, taken as the average of the three titration methods, was significantly smaller than the number of framework Al atoms (Alf) obtained from X-ray diffraction and 27Al magic angle spinning nuclear magnetic resonance spectroscopy on H-USY (0.35 H+/Alf) and CD-HUSY (0.69 H+/Alf). These data demonstrate that the ubiquitous use of Alf sites as structural proxies for active H+ sites in zeolites can be imprecise, apparently because distorted Al structures that are not associated with acidic protons are sometimes detected as Alf sites. Monomolecular isobutane cracking and dehydrogenation rate constants, normalized non-rigorously by the number of Alf species, decreased with increasing Na+ content on both H-USY and CD-HUSY samples and became undetectable at sub-stoichiometric exchange levels (0.32 and 0.72 Na+/Alf ratios, respectively), an unexpected finding attributed incorrectly in previous studies to the presence of minority ��super-acidic�� sites. These rate constants, when normalized rigorously by the number of residual H+ sites were independent of Na+ content on both H-USY and CD-HUSY samples, reflecting the stoichiometric replacement of protons that are uniform in reactivity by Na+ cations. Monomolecular isobutane cracking and dehydrogenation rate constants (per H+; 763 K), however, were higher on H-USY than CD-HUSY (by a factor of 1.4). Equilibrium constants for the formation of protonated methanol dimers via adsorption of gaseous methanol onto adsorbed methanol monomers, determined from kinetic studies of methanol dehydration to dimethyl ether (433 K), were also higher on H-USY than CD-HUSY (by a factor of 2.1). These larger constants predominantly reflect stronger dispersive interactions in H-USY, consistent with its smaller supercage voids that result from the occlusion of void space by extraframework Al (Alex) residues. These findings appear to clarify enduring controversies about the mechanistic interpretation of the effects of Na+ and Alex species on the catalytic reactivity of FAU zeolites. They also illustrate the need to normalize rates by the number of active sites instead of more convenient but less accurate structural proxies for such sites.
Chemical compatibility screening test results
Nigrey, P.J.; Dickens, T.G.
A program for evaluating packaging components that may be used in transporting mixed-waste forms has been developed and the first phase has been completed. This effort involved the screening of ten plastic materials in four simulant mixed-waste types. These plastics were butadiene-acrylonitrile copolymer rubber, cross-linked polyethylene (XLPE), epichlorohydrin rubber, ethylene-propylene rubber (EPDM), fluorocarbon (Viton or Kel-F), polytetrafluoroethylene, high-density polyethylene (HDPE), isobutylene-isoprene copolymer rubber (butyl), polypropylene, and styrene-butadiene rubber (SBR). The selected simulant mixed wastes were (1) an aqueous alkaline mixture of sodium nitrate and sodium nitrite; (2) a chlorinated hydrocarbon mixture; (3) a simulant liquid scintillation fluid; and (4) a mixture of ketones. The testing protocol involved exposing the respective materials to 286,000 rads of gamma radiation followed by 14-day exposures to the waste types at 60{degrees}C. The seal materials were tested using vapor transport rate (VTR) measurements while the liner materials were tested using specific gravity as a metric. For these tests, a screening criterion of 0.9 g/hr/m{sup 2} for VTR and a specific gravity change of 10% was used. Based on this work, it was concluded that while all seal materials passed exposure to the aqueous simulant mixed waste, EPDM and SBR had the lowest VTRs. In the chlorinated hydrocarbon simulant mixed waste, only Viton passed the screening tests. In both the simulant scintillation fluid mixed waste and the ketone mixture simulant mixed waste, none of the seal materials met the screening criteria. For specific gravity testing of liner materials, the data showed that while all materials with the exception of polypropylene passed the screening criteria, Kel-F, HDPE, and XLPE offered the greatest resistance to the combination of radiation and chemicals.
Effects of simulant mixed waste on EPDM and butyl rubber
Nigrey, P.J.; Dickens, T.G.
The authors have developed a Chemical Compatibility Testing Program for the evaluation of plastic packaging components which may be used in transporting mixed waste forms. In this program, they have screened 10 plastic materials in four liquid mixed waste simulants. These plastics were butadiene-acrylonitrile copolymer (Nitrile) rubber, cross-linked polyethylene, epichlorohydrin rubber, ethylene-propylene (EPDM) rubber, fluorocarbons (Viton and Kel-F{trademark}), polytetrafluoro-ethylene (Teflon), high-density polyethylene, isobutylene-isoprene copolymer (Butyl) rubber, polypropylene, and styrene-butadiene (SBR) rubber. The selected simulant mixed wastes were (1) an aqueous alkaline mixture of sodium nitrate and sodium nitrite; (2) a chlorinated hydrocarbon mixture; (3) a simulant liquid scintillation fluid; and (4) a mixture of ketones. The screening testing protocol involved exposing the respective materials to approximately 3 kGy of gamma radiation followed by 14-day exposures to the waste simulants at 60 C. The rubber materials or elastomers were tested using Vapor Transport Rate measurements while the liner materials were tested using specific gravity as a metric. The authors have developed a chemical compatibility program for the evaluation of plastic packaging components which may be incorporated in packaging for transporting mixed waste forms. From the data analyses performed to date, they have identified the thermoplastic, polychlorotrifluoroethylene, as having the greatest chemical compatibility after having been exposed to gamma radiation followed by exposure to the Hanford Tank simulant mixed waste. The most striking observation from this study was the poor performance of polytetrafluoroethylene under these conditions. In the evaluation of the two elastomeric materials they have concluded that while both materials exhibit remarkable resistance to these environmental conditions, EPDM has a greater resistance to this corrosive simulant mixed waste.
Polymer Growth Rate in a Wire Chamber with Oxygen,Water, or Alcohol Gas Additives
Boyarski, Adam; /SLAC
The rate of polymer growth on wires was measured in a wire chamber while the chamber was aged initially with helium-isobutane (80:20) gas, and then with either oxygen, water, or alcohol added to the gas. At the completion of the aging process for each gas mixture, the carbon content on the wires was measured in a SEM/EDX instrument. The same physical wires were used in all the gas mixtures, allowing measurement of polymer build up or polymer depletion by each gas additive. It is found that the rate of polymer growth is not changed by the presence of oxygen, water or alcohol. Conjecture that oxygen reduces breakdown by removing polymer deposits on field wires is negated by these measurements. Instead, it appears that the reduced breakdown is due to lower resistance in the polymer from oxygen ions being transported into the polymer. It is also observed that field wires bombarded by the electrons in the SEM and then placed back into the chamber show an abundance of single electrons being emitted, indicating that electron charge is stored in the polymer layer and that a high electric field is necessary to remove the charge.
Technical and operational overview of the C[sub 4] Oleflex process at Valero refinery
Hohnholt, J.F.; Payne, D. (Valero Refining Co., Corpus Christi, TX (United States)); Gregor, J.; Smith, E. (UOP, Des Plaines, IL (United States))
Changes in gasoline composition stemming from the 1990 Clean Air Act (CAA) Amendments prompted Valero Energy Corporation to evaluate options for producing reformulated gasoline. The evaluation culminated in a project to upgrade butanes into methyl tertiary butyl ether (MTBE). Technology selection focused on the dehydrogenation of isobutane, and the UOP Oleflex process was selected. The MTBE project was implemented in 34 months and was $3 million under budget. The guaranteed MTBE production of 12,500 BPSD was achieved within one month of mechanical completion and has since reached 15,000 BPSD. Even at the low MTBE prices prevailing in late 1993, the butane upgrading project contributed significantly to Valero Refinery's overall profitability. Worldwide demand is expected to increase MTBE prices in 1996, thereby further increasing profits. The paper describes the project evaluation activities which led to the selection of the Oleflex process, engineering and construction, the MTBE complex start-up and operation, the Valero MTBE complex performance, and future plans. The paper also discusses feedstock utilization efficiency and MTBE market analysis.
Butane segregated by fluorides, olefins content at Texas terminals
Not Available
Texas Eastern Products Pipeline Co., Houston (Teppco), this month has begun segregating butane streams at the company's Mont Belvieu and Baytown, Texas terminals according to fluoride and olefin contents. Streams containing fluoride or an olefin content greater than 1 ppm (or both) currently flow into Teppco's south Mont Belvieu terminal. Those fluoride-free streams with less than 1 ppm of olefins flow to its north Mont Belvieu terminal. Butane processed through an isomerization unit yields isobutane, a key component in MTBE. But high-fluoride butane from crude-oil refineries using hydrofluoric (HF) acid alkylation units cannot be used to produce MTBE because fluoride will damage isomerization units' process catalysts. Olefins also affect the efficiency of isomerization units, but less critically than fluorides. Their presence is higher in refinery product than in fractionated NGL. To extend the life of their process catalysts and to maximize yields, producers (including MTBE and isomerization unit operators) are specifying low-fluoride butanes developed from natural-gas fractionators or from refineries that do not use an HF process.
Catalytic conversion of light alkanes, Phase 3. Topical report, January 1990--December 1992
The mission of this work is to devise a new catalyst which can be used in the first simple, economic process to convert the light alkanes in natural gas to an alcohol-rich oxygenated product which can either be used as an environmentally friendly, high-performance liquid fuel, or a precursor to a liquid hydrocarbon transportation fuel. The authors have entered the proof-of-concept stage for converting isobutane to tert butyl alcohol in a practical process and are preparing to enter proof-of-concept of a propane to isopropyl alcohol process in the near future. Methane and ethane are more refractory and thus more difficult to oxidize than the C{sub 3} and C{sub 4} hydrocarbons. Nonetheless, advances made in this area indicate that further research progress could achieve the goal of their direct conversion to alcohols. Progress in Phase 3 catalytic vapor phase methane and ethane oxidation over metals in regular oxidic lattices are the subject of this topical report.
Design and analysis of a 5-MW vertical-fluted-tube condenser for geothermal applications
Llewellyn, G.H.
The design and analysis of an industtial-sized vertical-fluted-tube condenser. The condenser is used to condense superheated isobutane vapor discharged from a power turbine in a geothermal test facility operated for the US Department of Energy. The 5-MW condenser has 1150 coolant tubes in a four-pass configuration with a total heat transfer area of 725 m/sup 2/ (7800 ft/sup 2/). The unit is being tested at the Geothermal Components Test Facility in the Imperial Valley of East Mesa, California. The condenser design is based on previous experimental research work done at the Oak Ridge National Laboratory on condensing refrigerants on a wide variety of single vertical tubes. Condensing film coefficients obtained on the high-performance vertical fluted tubes in condensing refrigerants are as much as seven times greater than those obtained with vertical smooth tubes that have the same diameter and length. The overall heat transfer performance expected from the fluted tube condenser is four to five times the heat transfer obtained from the identical units employing smooth tubes. Fluted tube condensers also have other direct applications in the Ocean Thermal Energy Conversion (OTEC) program in condensing ammonia, in the petroleum industry in condensing light hydrocarbons, and in the air conditioning and refrigeration industry in condensing fluorocarbon vapors.
Recovery of energy from geothermal brine and other hot water sources
Wahl, III, Edward F. (Claremont, CA); Boucher, Frederic B. (San Juan Capistrano, CA)
Process and system for recovery of energy from geothermal brines and other hot water sources, by direct contact heat exchange between the brine or hot water, and an immiscible working fluid, e.g. a hydrocarbon such as isobutane, in a heat exchange column, the brine or hot water therein flowing countercurrent to the flow of the working fluid. The column can be operated at subcritical, critical or above the critical pressure of the working fluid. Preferably, the column is provided with a plurality of sieve plates, and the heat exchange process and column, e.g. with respect to the design of such plates, number of plates employed, spacing between plates, area thereof, column diameter, and the like, are designed to achieve maximum throughput of brine or hot water and reduction in temperature differential at the respective stages or plates between the brine or hot water and the working fluid, and so minimize lost work and maximize efficiency, and minimize scale deposition from hot water containing fluid including salts, such as brine. Maximum throughput approximates minimum cost of electricity which can be produced by conversion of the recovered thermal energy to electrical energy.
Investigation of pressure drop in capillary tube for mixed refrigerant Joule-Thomson cryocooler
Ardhapurkar, P. M. [Mechanical Engineering Department, Indian Institute of Technology Bombay, Mumbai, MS 400 076 India and S. S. G. M. College of Engineering Shegaon, MS 444 203 (India); Sridharan, Arunkumar; Atrey, M. D. [Mechanical Engineering Department, Indian Institute of Technology Bombay, Mumbai, MS 400 076 (India)
A capillary tube is commonly used in small capacity refrigeration and air-conditioning systems. It is also a preferred expansion device in mixed refrigerant Joule-Thomson (MR J-T) cryocoolers, since it is inexpensive and simple in configuration. However, the flow inside a capillary tube is complex, since flashing process that occurs in case of refrigeration and air-conditioning systems is metastable. A mixture of refrigerants such as nitrogen, methane, ethane, propane and iso-butane expands below its inversion temperature in the capillary tube of MR J-T cryocooler and reaches cryogenic temperature. The mass flow rate of refrigerant mixture circulating through capillary tube depends on the pressure difference across it. There are many empirical correlations which predict pressure drop across the capillary tube. However, they have not been tested for refrigerant mixtures and for operating conditions of the cryocooler. The present paper assesses the existing empirical correlations for predicting overall pressure drop across the capillary tube for the MR J-T cryocooler. The empirical correlations refer to homogeneous as well as separated flow models. Experiments are carried out to measure the overall pressure drop across the capillary tube for the cooler. Three different compositions of refrigerant mixture are used to study the pressure drop variations. The predicted overall pressure drop across the capillary tube is compared with the experimentally obtained value. The predictions obtained using homogeneous model show better match with the experimental results compared to separated flow models.
Petroleum production at maximum efficient rate, Naval Petroleum Reserve No. 1 (Elk Hills), Kern County, California. Draft Supplement to the 1979 Final Environmental Impact Statement
Not Available
The proposed action involves the continued operation of the Naval Petroleum Reserve No. 1 (NPR-1) at the Maximum Efficiency Rate (MER) through the year approximately 2025 in accordance with the requirements of the Naval Petroleum Reserves Production Act of 1976 (P.L. 94-258). NPR-1 is a large oil and gas field comprising 74 square miles. MER production primarily includes continued operation and maintenance of existing facilities; a well drilling and abandonment program; construction and operation of future gas processing, gas compression, and steamflood, waterflood, cogeneration, and butane isomerization facilities; and continued implementation of a comprehensive environmental protection program. The basis for the draft environment impact statement (DSEIS) proposed action is the April 1989 NPR-1 Long Range Plan which describes a myriad of planned operational, maintenance, and development activities over the next 25--30 years. These activities include the continued operation of existing facilities; additional well drilling; expanded steamflood operations; expanded waterflood programs; expanded gas compression, gas lift, gas processing and gas injection; construction of a new cogeneration facility; construction of a new isobutane facility; and a comprehensive environmental program designed to minimize environmental impacts.
Characterization of a Spherical Proportional Counter in argon-based mixtures
F. J. Iguaz; A. Rodriguez; J. F. Castel; I. G. Irastorza
The Spherical Proportional Counter is a novel type of radiation detector, with a low energy threshold (typically below 100 eV) and good energy resolution. This detector is being developed by the network NEWS, which includes several applications. We can name between many others Dark Matter searches, low level radon and neutron counting or low energy neutrino detection from supernovas or nuclear reactors via neutrino-nucleus elastic scattering. In this context, this works will present the characterization of a spherical detector of 1 meter diameter using two argon-based mixtures (with methane and isobutane) and for gas pressures between 50 and 1250 mbar. In each case, the energy resolution shows its best value in a wide range of gains, limited by the ballistic effect at low gains and by ion-backflow at high gains. Moreover, the best energy resolution shows a degradation with pressure. These effects will be discussed in terms of gas avalanche properties. Finally, the effect of an electrical field corrector in the homogenity of the gain and the energy threshold measured in our setup will be also discussed.
Conductive porous scaffolds as potential neural interface materials.
Hedberg-Dirk, Elizabeth L.; Cicotte, Kirsten N.; Buerger, Stephen P.; Reece, Gregory; Dirk, Shawn M.; Lin, Patrick P.
Our overall intent is to develop improved prosthetic devices with the use of nerve interfaces through which transected nerves may grow, such that small groups of nerve fibers come into close contact with electrode sites, each of which is connected to electronics external to the interface. These interfaces must be physically structured to allow nerve fibers to grow through them, either by being porous or by including specific channels for the axons. They must be mechanically compatible with nerves such that they promote growth and do not harm the nervous system, and biocompatible to promote nerve fiber growth and to allow close integration with biological tissue. They must exhibit selective and structured conductivity to allow the connection of electrode sites with external circuitry, and electrical properties must be tuned to enable the transmission of neural signals. Finally, the interfaces must be capable of being physically connected to external circuitry, e.g. through attached wires. We have utilized electrospinning as a tool to create conductive, porous networks of non-woven biocompatible fibers in order to meet the materials requirements for the neural interface. The biocompatible fibers were based on the known biocompatible material poly(dimethyl siloxane) (PDMS) as well as a newer biomaterial developed in our laboratories, poly(butylene fumarate) (PBF). Both of the polymers cannot be electrospun using conventional electrospinning techniques due to their low glass transition temperatures, so in situ crosslinking methodologies were developed to facilitate micro- and nano-fiber formation during electrospinning. The conductivity of the electrospun fiber mats was controlled by controlling the loading with multi-walled carbon nanotubes (MWNTs). Fabrication, electrical and materials characterization will be discussed along with initial in vivo experimental results.
Papers from U.S. Department of Energy Science Undergraduate Laboratory Internship Program (SULI) 2006
Edwards, A., (ed.); Majewski, S., (ed.); Woods, M., (ed.)
The BaBar drift chamber (DCH) is used to measure the properties of charged particles created from e{sup +}e{sup -} collisions in the PEP-II asymmetric-energy storage rings by making precise measurements of position, momentum and ionization energy loss (dE/dx). In October of 2005, the PEP-II storage rings operated with a luminosity of 10 x 10{sup 33} cm{sup -2}s{sup -1}; the goal for 2007 is a luminosity of 20 x 10{sup 33} cm{sup -2}s{sup -1}, which will increase the readout dead time, causing uncertainty in drift chamber measurements to become more significant in physics results. The research described in this paper aims to reduce position and dE/dx uncertainties by improving our understanding of the BaBar drift chamber performance. A simulation program --called garfield--is used to model the behavior of the drift chamber with adjustable parameters such as gas mixture, wire diameter, voltage, and magnetic field. By exploring the simulation options offered in garfield, we successfully produced a simulation model of the BaBar drift chamber. We compared the time-to-distance calibration from BaBar to that calculated by garfield to validate our model as well as check for discrepancies between the simulated and calibrated time-to-distance functions, and found that for a 0{sup o} entrance angle there is a very good match between calibrations, but at an entrance angle of 90{sup o} the calibration breaks down. Using this model, we also systematically varied the gas mixture to find one that would optimize chamber operation, which showed that the gas mixture of 80:20 Helium:isobutane is a good operating point, though more calculations need to be done to confirm that it is the optimal mixture.
The use of acetylene and 1,3-butadiene as tracers for vehicular combustion in urban air and the estimation of the contributions of vehicular emissions to benzene, and alkane concentrations in the Edmonton industrial area
Bailey, R. [Environment Canada, Edmonton, Alberta (Canada). Prairie and Northern Region; Wong, R. [Alberta Environmental Protection, Edmonton, Alberta (Canada); Dann, T.; Wang, D. [Environment Canada, Gloucester, Ontario (Canada). Environmental Protection Service
Acetylene, propylene and 1,3-butadiene concentrations at two downtown urban sites in Alberta, Canada were used to characterize an area dominated by vehicular emissions. The relationship of acetylene with 1,3-butadiene at the Edmonton industrial site was similar to that observed for the two downtown sites. This suggesting that these volatile organic compounds, VOCs, can be used as tracers for vehicular emissions for the Edmonton industrial area. The tracer VOCs were found to correlate with benzene, n-butane, iso-butane, n-pentane, iso-pentane, n-heptane and n-octane concentrations for the two Alberta downtown sites. The best fit lines from the downtown sites were used to predict daily concentrations of benzene and alkanes at the Edmonton industrial site. During the winter, when benzene levels are predicted to reach a maximum of 4.5 to 6.5 m g/m{sup 3}, it is estimated that industrial sources contribute < 1 m g/m{sup 3} to ambient levels at the Edmonton industrial site. During the summer, when predicted benzene levels are at a minimum of 1 to 2 m g/m{sup 3}, industrial area sources dominate the ambient benzene levels at the Edmonton industrial site, and can contribute up to 6 m g/m{sup 3}. For alkanes, such as butane and pentane, industrial area sources or evaporative storage tank emissions dominate throughout the year. This dominance of industrial sources is also observed for n-heptane and n-octane during summer months. During the winter when predicted n-heptane and n-octane concentrations reach a maximum, 11 to 100% of ambient daily levels can be attributed to vehicular emissions.
Anderson, J.H.; Bilbow, W.M.
The objective of this study was to make a more refined evaluation of the Anderson Quin Cycle based on most recent information on the performance of various elements that will be used in the Anderson Quin Cycle. My original estimate of the work plan for evaluating and optimizing the Anderson Quin Cycle called for 7000 man hours of work. Since this grant was limited to 2150 man hours, we could not expect to achieve all the objectives within the allotted period of work. However, the most relevant program objectives have been completed as reported here. The analysis generally confirms the results originally estimated in my paper on the subject. (Ref. 2) Further optimizations should show even higher efficiencies. The Anderson Quin Cycle (US Patent applied for) basically consists of 5 elements in the power cycle: A refrigeration system to cool and clean the inlet air before it enters the compressor that supplies air for the gas turbine; a gas turbine consisting of a compressor, combustor, and turbine; a steam boiler and steam turbine system using the heat from the exhaust gas out of the gas turbine; a vapor turbine cycle, which utilizes the condensed heat from the exhaust of the steam turbine and the exhaust gas heat leaving the steam boiler to operate a vapor turbine cycle which utilizes another fluid than water, in this case isobutane; and the fifth element consists of a gas cooler and heat pump system, which removes the heat from the exhaust gas to lower its temperature essentially to atmospheric temperature, and at the same time permits treatment of the exhaust gas to remove acid components such as sulfur dioxide and nitrogen oxides. Current industry accepted component characteristics were incorporated in the performance analysis of the overall cycle, ensuring accurate and meaningful operating predictions. The characteristics and performance of each of the elements are described. The thermal efficiency of the optimized calculated Anderson Quin Cycle is 62 percent.
The Anderson Quin Cycle. Final report
Anderson, J.H.; Bilbow, W.M.
The objective of this study was to make a more refined evaluation of the Anderson Quin Cycle based on most recent information on the performance of various elements that will be used in the Anderson Quin Cycle. My original estimate of the work plan for evaluating and optimizing the Anderson Quin Cycle called for 7000 man hours of work. Since this grant was limited to 2150 man hours, we could not expect to achieve all the objectives within the allotted period of work. However, the most relevant program objectives have been completed as reported here. The analysis generally confirms the results originally estimated in my paper on the subject. (Ref. 2) Further optimizations should show even higher efficiencies. The Anderson Quin Cycle (US Patent applied for) basically consists of 5 elements in the power cycle: A refrigeration system to cool and clean the inlet air before it enters the compressor that supplies air for the gas turbine; a gas turbine consisting of a compressor, combustor, and turbine; a steam boiler and steam turbine system using the heat from the exhaust gas out of the gas turbine; a vapor turbine cycle, which utilizes the condensed heat from the exhaust of the steam turbine and the exhaust gas heat leaving the steam boiler to operate a vapor turbine cycle which utilizes another fluid than water, in this case isobutane; and the fifth element consists of a gas cooler and heat pump system, which removes the heat from the exhaust gas to lower its temperature essentially to atmospheric temperature, and at the same time permits treatment of the exhaust gas to remove acid components such as sulfur dioxide and nitrogen oxides. Current industry accepted component characteristics were incorporated in the performance analysis of the overall cycle, ensuring accurate and meaningful operating predictions. The characteristics and performance of each of the elements are described. The thermal efficiency of the optimized calculated Anderson Quin Cycle is 62 percent.
Gas hydrate research in the Gulf of Mexico: Final report
Bennet, R.
The high energy seismic sections on the continental slope showed no evidence of a Bottom Simulating Reflector (BSR), which would indicate the presence of gas hydrates. There was no indication of metastable hydrates in continental shelf or slope sediments outside of the conventionally accepted temperature and pressure environment. Tracing the path of migrating gas from the source is much more straight forward than intercepting gas being transported and tracing it back to the source. Our study of low and medium energy seismic methods has shown that they could identify migrating gas. We feel strongly that there are hydrate zones in the Gulf of Mexico that are decomposing; they build up pressure and periodically release the trapped hydrocarbon gases. The released gases migrate vertically and/or laterally to mix with other types of gas or to form discrete pockets. Some of this gas may be emitted from underwater seeps into the overlying water column where it could be identified by a geochemical survey. The ratio of isobutane to normal butane determined by the geochemical survey can be used to assess the probability of the hydrocarbons emanating from a hydrate source. (The more the ratio exceeds 1.0 the greater the probability that the gas could be from a hydrate source.) As no indications of a hydrate zone (e.g., a BSR) were located, we were not able to establish a geophysical signature for gas hydrates; but the records indicate there are large volumes of gas migrating up the continental slope, some of which may have originated from a decomposing hydrate zone or from gas trapped below the hydrate cap. 20 refs., 13 figs., 1 tab.
Next Generation Geothermal Power Plants
Brugman, John; Hattar, Mai; Nichols, Kenneth; Esaki, Yuri
A number of current and prospective power plant concepts were investigated to evaluate their potential to serve as the basis of the next generation geothermal power plant (NGGPP). The NGGPP has been envisaged as a power plant that would be more cost competitive (than current geothermal power plants) with fossil fuel power plants, would efficiently use resources and mitigate the risk of reservoir under-performance, and minimize or eliminate emission of pollutants and consumption of surface and ground water. Power plant concepts were analyzed using resource characteristics at ten different geothermal sites located in the western United States. Concepts were developed into viable power plant processes, capital costs were estimated and levelized busbar costs determined. Thus, the study results should be considered as useful indicators of the commercial viability of the various power plants concepts that were investigated. Broadly, the different power plant concepts that were analyzed in this study fall into the following categories: commercial binary and flash plants, advanced binary plants, advanced flash plants, flash/binary hybrid plants, and fossil/geothed hybrid plants. Commercial binary plants were evaluated using commercial isobutane as a working fluid; both air-cooling and water-cooling were considered. Advanced binary concepts included cycles using synchronous turbine-generators, cycles with metastable expansion, and cycles utilizing mixtures as working fluids. Dual flash steam plants were used as the model for the commercial flash cycle. The following advanced flash concepts were examined: dual flash with rotary separator turbine, dual flash with steam reheater, dual flash with hot water turbine, and subatmospheric flash. Both dual flash and binary cycles were combined with other cycles to develop a number of hybrid cycles: dual flash binary bottoming cycle, dual flash backpressure turbine binary cycle, dual flash gas turbine cycle, and binary gas turbine cycle. Results of this study indicate that dual flash type plants are preferred at resources with temperatures above 400 F. Closed loop (binary type) plants are preferred at resources with temperatures below 400 F. A rotary separator turbine upstream of a dual flash plant can be beneficial at Salton Sea, the hottest resource, or at high temperature resources where there is a significant variance in wellhead pressures from well to well. Full scale demonstration is required to verify cost and performance. Hot water turbines that recover energy from the spent brine in a dual flash cycle improve that cycle's brine efficiency. Prototype field tests of this technology have established its technical feasibility. If natural gas prices remain low, a combustion turbine/binary hybrid is an economic option for the lowest temperature sites. The use of mixed fluids appear to be an attractive low risk option. The synchronous turbine option as prepared by Barber-Nichols is attractive but requires a pilot test to prove cost and performance. Dual flash binary bottoming cycles appear promising provided that scaling of the brine/working fluid exchangers is controllable. Metastable expansion, reheater, Subatmospheric flash, dual flash backpressure turbine, and hot dry rock concepts do not seem to offer any cost advantage over the baseline technologies. If implemented, the next generation geothermal power plant concept may improve brine utilization but is unlikely to reduce the cost of power generation by much more than 10%. Colder resources will benefit more from the development of a next generation geothermal power plant than will hotter resources. All values presented in this study for plant cost and for busbar cost of power are relative numbers intended to allow an objective and meaningful comparison of technologies. The goal of this study is to assess various technologies on an common basis and, secondarily, to give an approximate idea of the current costs of the technologies at actual resource sites. Absolute costs at a given site will be determined by the specifics of a given pr
Spectroelectrochemical Sensor for Pertechnetate Applicable to Hanford and Other DOE Sites
Heineman, William R; Seliskar, Carl J; Bryan, Samuel A
The general aim of our work funded by DOE is the design and implementation of a new sensor technology that offers unprecedented levels of specificity needed for analysis of the complex chemical mixtures found at DOE sites nationwide. The specific goal of this project was the development of a sensor for technetium (Tc) that is applicable to characterizing and monitoring the vadose zone and associated subsurface water at the Hanford Site and other DOE sites. The concept for the spectroelectrochemical sensor is innovative and represents a breakthrough in sensor technology. The sensor combines three modes of selectivity (electrochemistry, spectroscopy, and selective partitioning) into a single sensor to substantially improve selectivity. The sensor consists of a basic spectroelectrochemical configuration that we have developed under our previous DOE grants: a waveguide with an optically transparent electrode (OTE) that is coated with a thin chemically-selective film that preconcnetrates the analyte. The key to adapting this generic sensor to detect TcO4- and Tc complexes lies in the development of chemically-selective films that preconcentrate the analyte and, when necessary, chemically convert it into a complex with electrochemical and spectroscopic properties appropriate for sensing. Significant accomplishments were made in the general areas of synthesis and characterization of polymer films that efficiently preconcentrate the analyte, development and characterization of sensors and associated instrumentation, and synthesis and characterization of relevant Re and Tc complexes. Two new polymer films for the preconcentration step in the sensor were developed: partially sulfonated polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (SSEBS) and phosphine containing polymer films. The latter was a directed polymer film synthesis that combined the proper electrostatic properties to attract TcO4- and also incorporated a suitable ligand for covalently trapping a lower oxidation state Tc complex within the film for spectroelectrochemical detection. Spectroelectrochemical sensors were developed and demonstrated, first using [Re(dmpe)3]+ (dmpe = 1,2-bis(dimethylphosphino)ethane) as a model compound with the non-radioactive Re surrogate for radioactive Tc. A fluorescence based spectroelectrochemical sensor for [Tc(dmpe)3]+/2+was then developed using SSEBS as the preconcentrating film. Portable instrumentation for the fluorescence spectroelectrochemical sensor was fabricated and tested. The effects of components in Hanford subsurface water on sensor performance with a detailed evaluation of the effect of total ionic strength on sensitivity demonstrated the ability to use the spectroelectrochemical sensor on representative water samples. A variety Re and Tc complexes were synthesized and characterized to explore the best ligands to use for detection of Tc. A lower oxidation-state Tc-complex [Tc(dmpe)3]+ (dmpe = 1,2-bis(dimethylphosphino)ethane) was synthesized to use as a model compound for developing Tc sensors. [Tc(dmpe)3]+/2+ exhibited the important properties of solution fluorescence at ambient temperatures and reversible electrochemistry. A range of low oxidation state dioxo Re- and Tc-complexes of formulae [ReO2(py)4]+, [ReO2(CN)4]-, [ReO2(P-P)2]+ and [ReO2(S-S)2]+ (py = pyridine) were synthesized. An exhaustive study of the spectroscopy and electrochemistry of Re(diimine)(CO)3(halide) complexes was performed. These complexes served as models for the Tc(diimine)(CO)3(halide) complexes that were readily formed from Tc(CO)x(halides)6-x complexes which are themselves constituents of tank waste samples from Hanford. Of particular interest were new Tc complexes with the +5 and +6 oxidation states. Tetrabutylammonium salt of tetrachlorooxotechnetate(V), (nBu4N)[TcOCl4] (I) was synthesized and the structure determined. [TcO2(CN)4]3- , [TcO2(en)2]2+ , [TcO2(im)4]+, and [TcO2(py)4]+ (en = ethylenediamine; im = imidazole; py = pyridine) complexes were synthesized and solution and solid state 99Tc NMR spectra were acquired giving