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While for most people, the idea of a dangerous drug brings to mind heroin, crack, and even methamphetamine, OxyContin is actually one of the deadliest and most addictive substances available. The fact that OxyContin is manmade and is accessible through a doctor's prescription does not make it safer for human use than a drug like heroin. In fact, prescriptions for OxyContin are what have led to the majority of drug use progressing to abuse and onto addiction in the United States.
OxyContin: The Drug
OxyContin, the brand name of Purdue Pharmaceuticals' pill version of the painkiller, oxycodone, is a narcotic, just like heroin. Along with Vicodin, Percodan, Percocet, morphine, codeine, methadone and heroin, OxyContin and this entire classification of drugs, called opiates or opioids, have an extremely high rate of abuse, an even higher rate of addiction, and an undeniable link as the cause of thousands of overdose deaths every year.
What Does OxyContin Do?
OxyContin, created to mimic the effects of morphine, is comprised mainly of oxycodone. The drug works by blocking pain messengers in the brain, via the central nervous system. Internal levels of the natural neurotransmitter, dopamine, are affected, making the individual feel more pleasure and even euphoria, but the whole experience is chemically created. As a result, organic dopamine production is thrown out of whack, and the drug seems to be the only way to ever have a positive experience again.
When used properly, as medically prescribed, OxyContin is a highly effective painkiller that relieves the suffering of cancer patients and those with major physical pain. In an effort to treat acute and chronic pain, the Food and Drug Administration (FDA) approved OxyContin for medical use in 1995. Since its introduction to the medical community, OxyContin has quickly become one of the most addictive and most deadly drugs available. When taking more OxyContin than medically necessary, the drug produces a euphoric feeling, but that is never why a physician has recommended the drug for use.
Drug Formulation
The pill version of oxycodone was designed with a slow-release formula so that only the appropriate amount of medication makes its way into the user's bloodstream at any given time. With this method, ongoing pain can be properly alleviated. However, the potential for ways to abuse OxyContin were realized almost immediately. Instead of just relieving pain, OxyContin users figured out how to manipulate the drug to also get high.
OxyContin has been the subject of countless news reports and research studies. As the FDA witnessed the impact of OxyContin on the United States' population, the organization began conducting research studies. Results, published in The Journal of the American Medical Association, announced that oxycodone-related deaths increased 93% and oxycodone-related emergency room visits increased 32% between 1997 and 1998.
The Centers for Disease Control and Prevention (CDC) released information that 15,000 Americans died of opiate and opioid related deaths in 2008, which marked a 300% increase from 1999. The rate of prescription pill deaths in one year was more than the total number of deaths linked to heroin and cocaine combined. Further, in 2008, Purdue Pharmaceuticals reported over $2 billion in annual OxyContin sales, nearly double the amount sold in 2007. The drug's sales increased to nearly $3 billion the next year, and made it to $3.1 billion in 2010. This means that enough prescriptions for painkillers had been administered in 2010 to medicate every adult in the U.S., 24 hours a day, for an entire month.
Legal Involvement
After years of OxyContin sales, Purdue Pharmaceuticals was found liable for the drug's addiction and death rates. The company entered a guilty plea to a single felony count of misbranding and paid out $600.5 million. Plus, three of the company's top executives were each charged with misbranding misdemeanors and fined $34.5 million, which the company paid.
Changes to the Deadly Drug
As a result of the law suit, Purdue Pharmaceuticals reformulated OxyContin to reduce its abuse potential. Along with the changes came a new label warning of the drug's side effects, dangers, and probability toward addiction. The combined changed have proven effective in decreasing the demand for OxyContin.
OxyContin: The Effects
Unlike some other pharmaceutical drugs, the side effects of taking OxyContin are not mild. Instead of just possible dizziness and dry mouth, OxyContin affects the entire central nervous system. This means that the heart, the lungs, the brain, the reproductive, respiratory, digestive, and immune systems, and every major organ are impacted by the drug's abuse.
As a result, the Drug Enforcement Administration (DEA) reports record high cases of OxyContin abuse, physical and psychological dependence (i.e. addiction), and overdose deaths. Purdue Pharmaceuticals has been criticized for downplaying the dangers of OxyContin and has been required, by the FDA, to make changes to the label. The side effects are now listed right on the bottle of OxyContin along with what the FDA calls the strongest warning ever for a pharmaceutical drug.
- Depressed respiration, or respiratory failure
- Constipation
- Lowered blood pressure
- Slowed pulse
- Confusion
- Nausea, vomiting, or stomach cramps
- Slurred speech
- Lack of coordination
- Inability to stay awake
- Impairment of menstrual cycle in females
- Severe withdrawal symptoms when drug use stops
Increased OxyContin Use
Similar to heroin, an increased tolerance to the pain-blocking euphoric effects leads an OxyContin user to want a larger dosage of the drug each day. Accidental OxyContin overdose is caused when a user does not stop increasing the dose, until one day, the amount of the drug is too much for the body to metabolize. Rarely does an OxyContin overdose result in an outcome other than death or permanent brain damage.
Stopping the Progression of OxyContin Use
The dangerous side effects of OxyContin make its use incredibly risky. If you are using OxyContin, or know someone who is, the behavior can stop with the right medical help. Recovery Now TV finds the treatment centers with the most experience and the best staff to help stop the progression of OxyContin use to abuse and addiction.
Give Recovery Now TV a call today at 800-281-4731 to find out where you can start your new life.
OxyContin Abuse
When a prescription drug is used in any way other than how a doctor prescribed it, the drug is being abused. The purpose is no longer proper pain treatment; the goal is to get high.
If a 90-day supply of OxyContin is deemed necessary for recovery after surgery, for example, and the individual uses the given quantity in 60 days, the drug has been abused. Similarly, when a portion of one's personal quantity of OxyContin is sold to someone who does not also have a doctor's prescription, the drug is being abused.
- What is OxyContin Abuse?
- What Makes OxyContin Dangerous?
- The Progression From Use to Abuse
- What to Do About OxyContin Abuse
Although OxyContin was manufactured as a time-release pill, designed to relieve pain for up to 12 hours, when the drug is crushed and injected, snorted, chewed, smoked, or dissolved into a liquid, the time-release function is destroyed. Abusers feel a heroin-like rush from eating, drinking, snorting, or injecting the powdered, or pulverized, form of OxyContin.
The pleasurable feeling created by the abuse of OxyContin is leading even those who truly needed a prescription, to abuse the drug for the euphoria and the complete alleviation of all pain. Since the pharmaceutical drug can be so easily abused, often users quickly progress from legitimate use to abuse, and then onto addiction. Individuals who have not been educated on the dangers and side effects of OxyContin may not understand the drug's powerful narcotic impact on the human body.
All too often, a person who has been prescribed OxyContin believes that the drug is safe because a doctor has deemed it medically appropriate. Sadly, the true effects of OxyContin abuse are widely unknown to most of the people who are taking the pharmaceutical. Consequently, OxyContin's side effects become the reason for thousands of emergency room visits and causes of death every year.
According to the Substance Abuse and Mental Health Services Administration (SAMHSA), via the organization's Drug Abuse Warning Network, emergency room incidents involving oxycodone increased 89% between 1993 and 1999. Those rates jumped another 68% from 1999 to 2000; illustrating the reality of the influence OxyContin abuse is having on our society.
As one of the most powerful pain relievers on the market, OxyContin became a substitute for heroin. Instead of injecting a risky street drug, individuals started going to a doctor, complaining of chronic pain, in an effort to get what is essentially the pill form of heroin. The pharmaceutical versions seem less dangerous than heroin, are perceived with less cultural stigma than "street drugs," and come in a pretty little pill instead of via a needle, but make no mistake: prescription opiate narcotics are no less dangerous than any other version, like heroin, codeine, and morphine.
When the first high is experienced from OxyContin, abuse goes beyond just pain relief. The desire for an amount of the drug that creates that euphoric high is continuously pursued. For those users, who are not educated on the dangers of opiates, OxyContin use can unintentionally spiral out of control.
The body begins to change and chemicals in the brain begin to adapt to the continuous, and often rising, presence of OxyContin. The appropriate pain relief that used to come from one or two pills now requires five or six pills. As abuse continues to progress, it is not unusual for an individual to then need a dozen pills of OxyContin to feel the effect that used to come with just a couple. Physical tolerance to the drug has developed and the systems of the body and the brain now require more pills to ward off pain, or to get high.
When the body can no longer handle the dose that is being taken, meaning that the amount of the drug in the person's system can no longer be metabolized, the drug becomes lethal. This is an overdose. The body does not distinguish between OxyContin, another pharmaceutical, and heroin when dosages become so high that breathing stops and other organs shut down, including the heart. OxyContin overdoses are just like heroin overdoses. The body cannot handle the level of narcotics present.
The good news is that complete recovery from any opiate is possible. With help from trained professionals, OxyContin abuse can stop before an overdose, or the progression to addiction, ends a life.
Recovery Now TV offers the latest in medical detoxification and effective therapeutic techniques for treating OxyContin abuse. Through effective referrals, our treatment team will help find the best detox and treatment program for you. Call Recovery Now TV to find out more: 800-281-4731.
OxyContin Addiction
- Loss of control over substance use
- Obsession with use
- Continued use despite adverse life consequences
- Denial that there is a problem with a substance
- A powerful likelihood of relapse
Addiction is defined as a chronic disease with a high probability of relapse. When a person fits the criteria of addiction, he or she can be diagnosed with physical and psychological dependence upon at least one mind-altering drug, or life-impairing behavior. The ability to stop using is diminished, and every aspect of the person's life can reach incapacitation.
The use of OxyContin negatively impacts the entire central nervous system. The influence on the body and the brain decrease a person's ability to make good choices. OxyContin addiction begins to affect relationships, commitments, and responsibilities, as the drug begins taking daily priority. When abuse crosses over into addiction, jobs are lost, schoolwork falls by the wayside, relationships crumble, families are torn apart, physical and mental health deteriorates, and even legal consequences can begin dictating a person's life.
A well-cited definition of addiction includes these five criteria:
- A Loss of Control over substance use;
- Obsession with substance use;
- Continued use Despite Negative Life Consequences;
- Denial of a problem with substances and/or behaviors; and,
- A powerful tendency to Relapse back to substance use.
When used in an example, a person who has become addicted to OxyContin is unable to stop taking pills on his or her own. Each day this person is obsessed with finding the drug and using it, and even after this behavior has caused adverse life consequences (i.e. loss of a job, complete financial devastation, or the end of an important relationship), OxyContin use continues.
Through all of this, the addict denies that there is a problem with OxyContin, sometimes in the some form of, "I need the drug to treat my chronic pain." Denial is very powerful, and so is OxyContin. Even when use stops, whether the person admits a problem with the substance or not, someone who can be diagnosed with addiction returns to the drug, or relapses, often after just a short time of cessation.
Whether for you or for a loved one, this list provides signs and symptoms of addiction to look for in someone who is taking OxyContin:
- Feeling physically sick when the supply of OxyContin is gone. (i.e. withdrawal symptoms)
- Engaging in illegal activity to get OxyContin.
- Increasing the amount of OxyContin taken each day. (i.e. increased tolerance)
- Experiencing feelings of guilt or shame about OxyContin use.
- Losing a job, failing out of school, or losing a loved one because of OxyContin use.
- Changes in eating and sleeping patterns.
- Mood swings.
Additionally, in an effort to feel a satiable high again, many opiate addicts will combine alcohol, marijuana, cocaine, and other pharmaceutical drugs with OxyContin. This signals drug addiction. The act of combining chemicals is extremely dangerous because drug interactions in your body are unpredictable, and therefore, high risk and often life-threatening. Via several famous opiate addicts, like Heath Ledger, Cory Monteith, and most recently, Philip Seymour Hoffman, we see just how easily prescription pills, heroin, and the mixture of several drugs can lead to an untimely death.
Instead of suffering through the life of addiction, break the cycle by calling Recovery Now TV. OxyContin addiction must be treated, and with the help of our team, you can begin the detox and recovery process today.
Recovery Now TV has helped hundreds of people overcome opiate and opioid addiction. With proven techniques and effective medical procedures, recovery begins with medically supervised detoxification. Once OxyContin is out of the body, rehab can begin where treatment plans are customized to each individual client and a wide variety of services are available to heal the mind, body, and soul.
Give Recovery Now TV a call today at 800- 281-4731 to explore your options and to treat your OxyContin addiction.
Withdrawal from OxyContin
- Muscle and bone pain
- Restlessness
- Diarrhea
- Insomnia
- Vomiting
- Cold flashes
- Involuntary leg movements
OxyContin withdrawal is no less serious than quitting heroin, despite the fact that OxyContin use may have started with a legitimate doctor prescription.
Opiate and opioid withdrawal indicators are physical symptoms experienced when the body reacts to a lack of any drug in the opiate family. The body and the brain have become accustomed to having a painkiller to function, so when a substance like OxyContin is suddenly taken away, pain seems excruciating, digestion is a major problem, and the entire central nervous system revolts. Muscles cramp, bones and joints ache, and the entire body sweats. Nausea, an inability to sleep or eat, and a relentless experience of anxiety also ensue. Overall, OxyContin withdrawal produces flu-like symptoms and major discomfort.
The pain and distress of OxyContin withdrawal can be minimized under proper medical supervision. Recovery Now TV has connections with monitored detoxification programs for opiate addiction.
OxyContin withdrawal is not a process you want to go through on you own. To stand a chance at making it through the first few days without returning to OxyContin use, seek participation in one of Recovery Now TV's referrals with medical facilities, professional doctors, and licensed counselors helping you through the entire process.
Give us a call today at 800-281-4731 for a private consultation. We can help you stop using OxyContin and start a new life free of addiction.
Detox & Treatment
Completely ridding the body of OxyContin is vital for any chance at recovery from opiate addiction. As the most addictive class of drugs, these substances are not easily forgotten. With the assistance of medical professionals, who can administer proper medications and can continuously monitor vital signs, detoxification can be completed with greater ease.
Participation in a detox program sets a former OxyContin addict up for entry into a formal inpatient opiate treatment program. With individual therapy, peer group processing, family therapy, and other proven therapeutic approaches to recovery, an OxyContin addict can make changes with a positive attitude and a readiness to change. While not easy, a substance free life is available to addicts everywhere.
Recovery Now TV has dealt with hundreds of clients with your exact symptoms. Our effective treatment referrals are based on experience and research. If you are addicted to OxyContin, or someone in your life cannot stop using an opiate, it is time for help.
To find out where you can receive the best in opiate and opioid treatment, contact our team at Recovery Now TV, 800-281-4731. Our professional staff is standing by to give you a confidential consultation.


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It's safe to say that it hasn't been a vintage week for the British retail sector.
Coupled to the 'Horsegate' scandal which engulfed Tesco and other supermarkets, there was a triple whammy of woes for High Street retailers Jessops, HMV and Blockbuster – the latter of which you might be surprised was actually still going, much like Des O'Connor, or Angela Lansbury.
These three formerly dominant stores have all had to 'call in' the administrators - which presumably entails an A-Team-style van screeching to a halt at their respective head offices, with a crack team of highly trained accountants spilling out who then proceed to, er, administrate the place back into shape.
The Money Shot extends its sympathy not only to the employees of these stores, but also to the poor people who got gift tokens for these shops for Christmas – vouchers are rubbish presents at any rate, even when they are valid.
Sir Tony Baldry , a backbench Tory MP who also happens to be a practising barrister specialising in commercial law stuck the boot in to HMV management– the same bright sparks who thought it a good idea to try and sell copies of the Smashing Pumpkins 'Mellon Collie & The Infinite Sadness' for £25 a pop, allegedly decided that game-changing internet music sites like Napster were 'too geeky', and diluted their core offering of, you know, music, with overpriced electrical goods and band merchandise.
"Directors and management must have known that the company was at very real risk of failure whilst they continued selling vouchers all through Christmas and up until the day they went into administration" thundered Sir Tony, as his barrister's wig slipped from his head with the ferocity of his tirade. (We imagine.)
It's thought that about £100m worth of HMV vouchers are unspent. But what on earth can you do if you've got some in your possession? In an uncharacteristic moment of actually being useful, the Money Shot will tell you...
Here's the good news – when the administrators get called in, voucher holders are counted as creditors, and could get their money back once all the store's assets are sold off and there's enough money to go round….
Unfortunately, they're pretty low down the pecking order of creditors – suppliers, distributors, landlords and the like come higher up the food chain.
The Trading Standards Institute says that you should ACT NOW if you want to reclaim your vouchers, so if you're in possession of vouchers which aren't being accepted, put your best claim-lodging trousers on and get stuck in.
Some retailers actually let voucher holders redeem them – Blockbuster is currently doing this. And there's the chance that administrators could have a change of heart, like those at Comet did last year, before shutting for good just before Christmas
And there may even be an outside likelihood that a shop steps in and honours your vouchers some way, kind of like a retail knight in shining armour – independent store Banquet Records in Kingstone-upon-Thames is offering a 50% off offer to HMV voucher holders.
Anyway, let's hope that we've all learned our lesson – in future, think about just giving people the money.
To the delight of voyeurs everywhere, rightwing 'think tank' Policy Exchange has recommended that households should be able to anonymously compare other energy bills on the same street to make sure that they're getting the best deal.
'The banks' have been given a stern "do that again and you'll get a smacked bottom" warning from the Financial Services Authority over bonuses and commissions which encourage their staff to actively rip off customers. If they don't, they'll be the subject of a 'major crackdown', whatever that means.
Former justice secretary Jack Straw has said that insurers should be able to challenge bogus car insurance claims – not just those pertaining to notoriously difficult-to-diagnose whiplash.
E.On gas and electricity price 'hikes' are due to kick in. Boo! Etc…
Run yourself a deep, sensual bubblebath, dim the lights, stick on some Demis Roussos 'pon de stereo and let Covered mag's very own Mr Lover Lover, Dave Jenkins, whisper sweet nothings in your ear regarding Valentine's Day on the cheap.
With all the chatter around child benefits, Felicity Hannah pored over what free stuff for parents is available out there.
Long convoluted routes. Arrivals at ungodly hours. Stop-offs in places you never thought existed. Are these things really worth the savings on long-haul flights? Jon Severs gives it to you straight on the matter.
Socialite, 'amateur video' sensation and main squeeze of Yeezy, Kim Kardashsian has 'channelled' comparison site ad man Gio Compario for this ritzy new look."I wouldn't mind but I don't have the excuse of being pregnant," chuckled Wynne Evans, who plays the much-loved character of Gio in the ads over the medium of popular social network, Twitter.

subset: commoncrawl


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Top Cell Phone Technologies
The way we use our phones is rapidly changing and it is uncertain anybody is really noticing. Phone technologies are plethora of new information, and dissecting all the madness should be left to the pros. But here are some seriously deep phone technologies to consider:
Flexible screens and the "internet of things"
Imagine a phone which could be folded and unfolded. This technology is here with Organic Light-Emitting Diode (OLED) technology. The Flexphone smart-phone could expand to replace all four screens (phone, tablet, PC, TV) in your house? It created a new take on e-paper easily turning a phone into a gaming device, tablets PC, or fully fledged media-player. You can also flip photos from one screen to another, shifting form-factors and easily morphing the phone into whatever device you need it to be.
If a Flex phone isn't your flavor, then how about the little item called the 'Round Phone'? This is the future, a phone that can connect to the "internet of things", and becomes a part of everyday life by how it interacts with us. The Round phone connects and adapt to a huge variety of items. Connect it to the fridge and to find out what food items you are missing, or connect it to a shower for the temperature of the water. It is like having a tiny round robot in your pocket.
Holograms and "The Minority Report" interactions
When Round phones have lost their novelty, how about a smart phone which moves into 3D territory with holograms loaded and ready to go? It may seem a bit far-fetched but holographic projections are not too far behind. Apple's 'Retina Display' provides a resolution sharper than what a human eye can perceive. Using elements of movement to pull, compress, or grab holograms with a Smartphone is a concept recently showcased in an ongoing development program. Holographic projections through user interaction are the next bus stop for 3D phones.
Gaming consoles on the run
Then there is always the in-built projector concept. Why not include a projector within? In 2010, Samsung Galaxy Beam was released. It features Digital Light Projection (DLP), a WVGA which projects at up to 50 inches in size at 15 lumens. Interactive gaming consoles just got better. Similar to Kinect, your voice and movements are captured and commands are issued to interact with the Smartphone. Some kinks will have to be worked out first, like the immense drain on battery life and the amount of light it outputs.
This is technology which has landed already into laps of development. With that, where else could cell phone technology go? We see Smartphones interacting with drones. Smartphones with augmented reality capabilities; how could it all possibly get better?
Hold your horses…
How about a self-powered cell phone? This is a dream come true for those that are continually running to charge their phones. The latest research in nano materials looks promising with super ultra efficient systems that would power your device using the vibrations of your voice or the tapping of your fingertips on a touchscreen. Piezoelectric materials generate a tiny electric current from mechanical movement. Microphones are just one of the many items which use this effect to turn sound into an electrical signal. Harnessing this current at a nano scale produces piezoelectricity.
It is always exciting to see unfolding and innovative new ideas in cell phone technologies. There is an anticipation and inner applause when we rush off to try out the new merchandise. The future outlook is a giddy one into uncharted territory, ideas from futuristic films brought to reality.


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'Tis the Season for Ghost Hunting
Subscribe to 105.7 The Hawk on
Well, of course, ghost hunters are always on the hunt.
But as we head towards All Hallow's Eve, there are many ways you can find out exactly how ghost hunting differs from ghost busting, or so that's what I'm guessing.
My neighbor is a ghost hunter and works with South Jersey Ghost Research. They don't just confine their searches to the southern part of the state, though.
For example, if you're interested in learning more, there are a couple of free lectures coming up at the Jersey shore.
They begin at 7:00 p.m. and include video, EVP (ghost "voices"), photo displays, and more.
There's a lecture coming up on Wednesday, October 24th, at the Stafford Branch of the O.C.L.S. at 129 N. Main Street in Manahawkin.
Can't make that one? There's another one the following night, Thursday, October 25th, at the Ocean County Library at the Pt. Pleasant Branch at 834 Beaver Dam Rd.
Further north, on October 20th, there will also be an appearance at the Red Bank Battlefield.
By "appearance", I mean South Jersey Ghost Research appearances, but hey, you never know…


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This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution license (
Biomass is relatively cleaner than coal and is the only renewable carbon resource that can be directly converted into fuel. Biomass can significantly contribute to the world's energy needs if harnessed sustainably. However, there are also problems associated with the thermal conversion of biomass. This paper investigates and discusses issues associated with the thermal conversion of coal and biomass as a blend. Most notable topics reviewed are slagging and fouling caused by the relatively reactive alkali and alkaline earth compounds (K2O, Na2O and CaO) found in biomass ash. The alkali and alkaline earth metals (AAEM) present and dispersed in biomass fuels induce catalytic activity during co-conversion with coal. The catalytic activity is most noticeable when blended with high rank coals. The synergy during co-conversion is still controversial although it has been theorized that biomass acts like a hydrogen donor in liquefaction. Published literature also shows that coal and biomass exhibit different mechanisms, depending on the operating conditions, for the formation of nitrogen (N) and sulfur species. Utilization aspects of fly ash from blending coal and biomass are discussed. Recommendations are made on pretreatment options to increase the energy density of biomass fuels through pelletization, torrefaction and flash pyrolysis to reduce transportation costs.
Energy is the cornerstone to economic stability and development. Since the industrial revolution, fossil fuels have stimulated economic growth especially in the developed world. Only recently have we realized that this accelerated economic growth has not occurred without a penalty. Carbon dioxide emissions from fossil fuels combustion, combined with land-use changes, have driven the concentration of this most significant greenhouse gas (GHG) to levels in our atmosphere not seen for at least 800,000 years, and probably many millions of years [
Coal fired power plants are still the largest source of electricity generation in the Unites States (contributing to about 42% of net electricity generation), and will keep their lead until 2040 [
Biomass is any organic matter recently derived from plants through photosynthesis. It is a versatile feedstock encompassing forestry and agricultural residues, organic waste by-products, energy crops, sewage sludge and biosolids, woody plants and municipal green waste [
Biomass in general has a high content of hydrogen (H), making it suitable as a blend to compensate the often-low H content of coal. Biomass as gasification feedstock, although giving a high hydrogen yield, has the disadvantage of low energy density because of its high oxygen and moisture content. This shortcoming is compensated for when blended with a higher energy content coal. Other challenges such as the seasonal limitation of biomass are somewhat mitigated through co-conversion with coal. The higher tar release (due to excessive volatile release and low gasification temperature from biomass gasification) is also reduced as blending with coal increases the temperature, enhancing tar cracking. Blending biomass and coal as feedstock can reduce the shortcomings of each fuel and boost the efficacy of the overall system.
The most attractive benefit of co-converting coal and biomass is certainly the reduction of GHG emissions and environmental pollution. Biomass, compared to coal, has lower sulfur, N and heavy metals. It is also carbon-neutral if produced sustainably, thus co-conversion of biomass and coal can make significant contributions in mitigating GHG emission and other emissions. Compared to carbon capture and storage (CCS), co-converting biomass with coal is relatively cost-effective, given the high energy penalty of CCS which can range from 15% to 40% of the energy output [
Co-conversion of coal and biomass offers a better prospect for cleaner coal utilization and a way to dispose wastes/biomass in an economical, safe, and environmentally-acceptable manner. Some research on these systems has been performed, however, the wide variability of parameters (type of feedstock, type of gasifier, gasification conditions) in these systems requires additional research to identify the most important parameters and clarify how they affect the co-conversion efficiency and product yield.
This present work critically examines literature on thermal co-conversion (liquefaction, pyrolysis, gasification, combustion) of coal and biomass from pre-processing of feedstock to product utilization. Given the complexity of gasification compared to other processes, it will be the focal process during this analysis.
Carbonaceous solid fuels, which include coal and biomass, are complex collections of organic polymers consisting of aromatic chains combined by hydrocarbons and other atoms such as oxygen, N, sulfur, potassium (K) and sodium (Na). Coals are mainly formed as the results of slow metamorphosis of biomass over a long period of time. The degree of that metamorphosis is among the criteria used to determine coal rank. For instance, the lower degree of metamorphosis is found in lignites and the maximum are found in low-volatile bituminous and anthracite coals. Intermediary stages are the subbituminous and other bituminous ranks [
Gasification produces synthesis gas (syngas) and by-products such as ash and tars. Whether the syngas is used for power generation or for liquid fuel production, a clean gas free from tar and other contaminants is required. Biomass gasification has the drawback of producing a high amount of tar, therefore, tar avoidance or removal becomes important. Updraft gasifiers (fixed bed) produce more tar than fluidized beds, and fluidized beds more than entrained flow gasifiers [
Obtaining a relatively clean gas suitable for liquid fuel production from carbonaceous fuels requires operation at high temperature, which can be easily met with entrained flow gasifiers. At such temperatures (≈1573–1973 K), a gas with very low concentration of tar, methane, and carbon dioxide is obtained, which significantly decreases the gas cleaning cost.
Modern entrained flow gasifiers using solid feed operate at a pressure of between 15 bar and 60 bar. These elevated pressures are advantageous for gas to liquid synthesis. Pressurizing synthesis gas requires more energy than pressurizing ox0ygen; the reason being that the volume of synthesis gas is about double the volume of oxygen required for its production [
The high reaction rates of entrained flow gasifiers demand very small feedstock input size (∼100 μm), easily achievable for friable materials like coal, but more challenging and energy-consuming for biomass due to its fibrous structure and hygroscopic nature. Therefore, the viability of entrained flow gasification of biomass relies on its pretreatment. Moreover, entrained flow gasifiers operate at high pressures and need injection of the fuel, which is usually introduced into the pressurized reactor through an alternating pressurized and depressurized lock system. The periodic procedure is suited for high bulk density fuels and moderate pressures. At low bulk densities (e.g., biomass) and higher pressures (>50 bar; e.g., operating pressure for subsequent liquid processes), the amount of lock gas can exceed the fuel weight. Therefore, a well-designed feeding system to withstand back pressure from the gasifier is required and this may be as expensive as the gasifier itself [
Torrefaction is a thermal treatment at a temperature of 473–573 K, near atmospheric pressure and in the absence of oxygen. Ciolkosz and Wallace [
Fast pyrolyis is a rapid heating process at about 773 K in an inert atmosphere. Rapid condensation of the vapors in one to a few seconds occurs, and more than half of the biomass mass can be obtained as liquid pyrolysis oil at the expense of low char and gas yield. In these conditions, the pyrolysis gases contain less than 10% of the biomass energy, which is consumed on-site as energy input to the pyrolysis process. The brittle char obtained is ground to a fine powder and suspended in the liquid pyrolysis oil to form the bioslurry, with an overall energy content of up to 80%–90% of the original biomass energy [
The dispersed nature of the biomass feedstock requires the pretreated fuel to be transported to a central plant where it is co-converted with coal. Important parameters in deciding which of the two pretreatment options to consider are the energy density and post processing of the pretreated fuel.
Bioslurry is denser (and less bulky) than torrefied biomass. Thus besides feeding bioslurry under pressure being easier; pneumatically feeding powdered torrefied wood requires pressurizing with an inert gas that reduces the calorific value and complicates the gas cleaning process. Another advantage of the fast pyrolysis process is that to avoid soil nutrients depletion, pyrolysis can be designed to optimize and obtain only an energy-rich bio-oil containing 60% to 70% of the original biomass energy [
Biomass fuels usually have a low as-received fixed carbon value compared to coals while the volatile matter values are higher, therefore, when co-gasifying coal and biomass, a low release of carbon-containing compounds such as CO2, CO, CH4 and other light hydrocarbons are expected in comparison, to gasifying coal. This is contrary to results obtained by [
Many co-conversion studies related to co-gasification studies have focused on parametric studies of the gasifier [
The generalized biomass pyrolysis model based on superimposed cellulose, hemicelluloses and lignin kinetics [
The mineral matter in biomass (especially the ion-exchangeable alkali metals) is expected to further promote catalytic activity when blended with coal. Whether the influence of biomass has a greater impact during gasification than pyrolysis is unclear, but the type of feedstock appears to be a major factor in this partitioning. This remark is highlighted by Storm
Since blending coal and biomass/waste (heat input base) leads to an increase of the volatile products (CO, CH4 and C
The merits of alkali (K+ and Na+) and alkaline earth (Ca2+) metals as catalysts for coal gasification have been extensively investigated [
The catalytic effect of biomass in co-gasification with coal is also expected to play an important role for the abatement of environmentally harmful species containing sulfur and nitrogen. Biomass species with a high content of K, Na and Ca can form sulfate and capture sulfur from the gas phase when co-processed with coal [
The synergistic effect of co-conversion of coal and biomass can be viewed in terms of:
increase in total volatiles (tars and light gases) release and decrease in char yield; overall decrease in pollutants (oxides of nitrogen and their precursors and well as SO
increase in total volatiles (tars and light gases) release and decrease in char yield;
overall decrease in pollutants (oxides of nitrogen and their precursors and well as SO
The increase in total volatiles released and corresponding decrease in char production has received the most attention for synergistic evaluations. In the literature on thermal co-conversion of coal and biomass/waste, the non-catalytic mechanism responsible for this observation has been attributed to free radical/hydrogen transfer. However, the existence of non-catalytic synergistic effect remains controversial. Some researchers [
It is obvious that interactions occurring between coal and biomass/waste during thermal conversion have not been sufficiently investigated and require further evaluation to elucidate the mechanism and conditions by which the two fuels interact when blended and converted.
As depicted in
This process has been thoroughly investigated. There is clear evidence of the interaction during co-liquefaction of some fuels. The earliest depiction of synergy mechanisms during co-liquefaction is probably by Coughlin and Davoudzadeh [
Pyrolysis is the decomposition of an organic material by heating in the absence of oxygen, but with inert gases or less reactive gases (argon and nitrogen) producing a viscous dark liquid (oil), gases and leaving a charring material composed mainly of carbon. Devolatilization on the other hand is the first step of combustion or gasification. It differs from pyrolysis with the presence of a reactive gas (O2, H2O, CO2,
Unlike liquefaction, no solvent is added to the organic feedstock during pyrolysis. Therefore, the thermal breakdown of the organic feedstock is not chemically enhanced, nor is there any hydrogen donor (solvent as in the case of liquefaction) to stabilize the radicals involved during thermal bond breaking.
As stated earlier, the literature on synergy during co-pyrolysis of solid fuels is controversial. Among co-pyrolysis studies that resulted in no synergy are that of Vuthaluru [
Jones cracking of tar to produce more gases in case of gasification; more reactive char for gasification and combustion.
cracking of tar to produce more gases in case of gasification;
more reactive char for gasification and combustion.
As mentioned in the previous section, synergy during gasification or combustion cannot be isolated from the pyrolysis/devolatilization step. Synergy during gasification/combustion is usually expressed in terms of the high amount of gases (gasification), high reactivity of the char (gasification and combustion), reduced pollutants (gasification and combustion). These observations occur as a consequence of the interactions occurred during pyrolysis/devolatilization. Kubacki [
The following explanation for synergy between coal and biomass/waste has been postulated [
The weak covalent bonds in biomass and the higher content of oxygen compared to coal causes its early reaction, therefore, releasing volatiles which break down and release free radicals or undergo combustion reactions with oxygen present in the system. The free radicals from biomass react with coal and enhance its decomposition. The gases resulting from cracking of the heavy volatiles from biomass, as well as light volatiles molecules from biomass are rich in hydrogen which react with coal's free radicals as hydrogen donors, therefore, preventing their recombination reactions and reduce the amount of less reactive secondary chars. This explanation is in accordance with similar conclusions made by Squire
Thus, hydrogen transfer between biomass and coal seems to be a plausible explanation of the synergistic effect between the two fuels. The hydrogen transfer mechanism between coal and solvents during coal liquefaction can provide some clue in the investigation of synergistic effects between coal and biomass during pyrolysis/devolatilization. In fact, co-liquefaction of coal and lignin [
The temperature dependence of the interaction between the coal and biomass seems to be consistent with the results of some researchers [
A thorough understanding of free radical formation and evolution during pyrolysis seems to be the key to the possible interaction between coal and biomass. While extensive studies have been conducted on free radicals release during coal pyrolysis [
There is no doubt that hydrogen donation is a key factor in improving the yield of oil and increasing the conversion of the feedstock during liquefaction. Investigation of hydrogen transfer from a liquid carrier (tetralin) to coal was first described as a free radical reaction with thermal breakage of the coal molecules by Curran
As the previous section described, the transfer of hydrogen to coal radicals is essential in achieving a higher yield of oil during liquefaction. It will be shown that improved pyrolysis is also achieved by effective transfer of hydrogen to free radicals. It has been suggested that the contact at the molecular level between the solvent and the fuel functional groups is essential in addition to the matching of the dehydrogenation rate of the solvent and the primary decomposition rate of coal. Miura
Non-catalytic synergistic effects observed in the release of volatiles and tar during coal biomass/waste co-conversion is evidenced by what precedes. The mechanism is a complex one, since in the case of biomass and coal, the release of hydrogen from biomass should match the free radical release from coal and the two fuels should be spatially close for the transfer to happen. The discrepancy observed in the scientific community about this topic is probably due to these constraints.
Tar can be defined as the organics, produced under thermal or partial-oxidation regimes of any organic material, and generally assumed to be largely aromatic [
Pressure is among the conversion factors that depend on the reactor condition. Bahng
During the devolatilization phase of coal gasification, increasing the pressure decrease the total volatile yield. Lee
The pressure effect during devolatization of biomass is similar to that of coal. Pindoria
The decrease in total volatiles is mostly due to the decrease in tar as pressure is increased. Pressure suppresses the formation and release of tar and shifts the molecular weight of tar to a lighter fraction while promoting secondary reactions that decompose tar. Therefore, decreases in the tar output occur as well as increases in the total yield of light gases [
A high pressure inhibits the release of larger tar molecules that may easily evaporate at lower pressures, which is a plausible explanation why tar yield decreases and most of the tars shift toward lower molecular weights. Secondary reactions may explain why the effect of pressure on total volatiles is more pronounced at higher temperatures. The secondary repolymerization of the tar and the auto-hydrogenation phenomenon occurring at elevated pressure may also explain the increase of hydrocarbon gas yields, particularly methane.
Arendt and van Heek [
Similar results were obtained by Güell
The effect of pressure on char formation and reactivity seems to be more complex. Reactivity of char is in fact highly dependent on the pyrolysis condition and pressure is one of the most important factors; it significantly affects the ash formation during char gasification as well. Under gasification conditions, one of the main parameters used for analyzing char reaction rate is its internal surface area. Higher pyrolysis pressures lead to lower surface area of char, and therefore, lower reactivity during gasification. Lee
Experiments with biomass show comparable results. Cetin
Several assumptions have been postulated to explain this observation. It's believed that high pressure may inhibit the transport effect during pyrolysis such as to reduce the release of volatile matters, causing large deposition on the pore surfaces, which creates secondary reactions, and therefore, deactivates active sites on the resulting char. Another assumption is that higher pyrolysis pressure enhances fluidity of coal, leading to a better mobility, alignment and ordering of carbon layers with reduction of micropores and subsequent loss of gasification reactivity. Concurrent influences of these two phenomena are also possible.
During combustion, nitrogen contained in solid fuels is converted to nitric oxides [NO
The origins, forms and modes of occurrence of nitrogen compounds (NH3 and HCN) during coal pyrolysis and gasification have been thoroughly investigated. Nitrogen in coal is mostly in pyrrolic and pyridinic forms [
Reaction pathways involving nitrogen during pyrolysis/gasification is complex due to the overlapping of reaction stages, the influence of reaction conditions (residence time, temperature, pressure and gasification agent) and the differences between fuels. During pyrolysis, part of the fuel bound nitrogen (FBN) is released with the devolatilizing gases while the remainder is retained in the solid char to be released during subsequent gasification/combustion of the char [
Given the predominance of proteins as the main nitrogen-containing compound in biomass, some researchers [
Compared to coal, biomass has a higher content of oxygen, which enhances the direct release of NO and isocyanic acid (HNCO) as part of the devolatilizing gases during pyrolysis. The presence of CO2 suppresses the release of HNCO while enhancing formation of NH3 and NO [
HNCO may also lose its hydrogen to give NCO, which then reacts with NO to give N2O and CO, it is therefore considered a precursor of N2O:
However, HCN is the main precursor of N2O [
The effect of particle size on FBN release is insignificant at lower temperatures (<673 K) but becomes considerable as the temperature increases. As the particle size increases, the yield of nitrogen species generally reduces [
Biomass also usually has a higher moisture content compared to most coals. Moisture can react with isocyanic acid to give ammonia and carbon monoxide, this reaction is known to be enhanced by the presence of CaO [
Therefore, larger particles with longer diffusion path may favor reaction of HCN with H2O and enhance formation of NH3 as has been observed by some researchers [
The effect of temperature on biomass fuel nitrogen has also been thoroughly investigated. Becidan
It is further confirmed based on a thermodynamic point of view that NH3 destruction is endothermic, hence could be favored at higher temperatures [
Fuel oxygen usually forms OH radicals and other oxygen-containing radicals during the pyrolysis stage of solid fuel conversion. These radicals may promote secondary reactions including conversion of HCN to NH3. High heating rates suppress these secondary reactions, and hence favor formation of HCN [
Higher heating rates appear to increase the HCN/NH3 ratio for both coal and biomass fuels [
The presence of Ca significantly reduces the emission of N2O probably by interfering with HCN chemistry [
Pressure only has a minor effect on the chemistry of biomass nitrogen. Although many investigations have been conducted on the effect of pressure on coal nitrogen release, very few have been done for biomass. The equivalence ratio as well as the gasifying agent are also negligible factors in biomass nitrogen chemistry. However, it has been observed that CO2 as a gasifying agent reduces formation of HCN and suppresses formation of HNCO [
Hydrogen cyanide is the primary product from devolatilization of coal nitrogen. Unlike ammonia, HCN has been observed in many experiments conducted at lower temperatures. The formation of HCN starts at 673 K and its profile can be divided into two parts: the release at an early stage as a result of the decomposition of the tar nitrogen and the elimination of CN-groups, and in a second high-temperature stage as a result of ring cleavage of hetero-aromatic compounds [
Nitrogen thermochemistry during coal conversion also depends strongly on the factors already listed for biomass: fuel type, temperature, particle size, heating rate, pressure and residence time [
This mechanism may explain why HNCO is observed in high-rank coals pyrolysis, but not in low-rank coals.
Analysis made in the last two sections show that nitrogen thermochemistry is complex and depends on many parameters. Whether synergy is observed in the decomposition of coal and biomass/waste blend should surely influence the release of fuel nitrogen. Yuan
It has been observed that more nitrogen is retained in the char during low temperature co-pyrolysis than higher temperatures. The reason evoked is that blending coal and biomass/waste reduces the packing density of the mixture. Since heat transfer is dominated by conduction at lower temperatures (as opposed to radiation at higher temperatures), the heating rate of the fuel is reduced and contributes to more nitrogen being retained in the char [
In thermal conversion of solid fuels, the release of fuel-bound nitrogen in the volatile is desirable over its' remaining in the char. With staged combustion, nitrogen compounds in the volatile are more susceptible to nitric oxides' control than char nitrogen. Their combustion occurs in two zones. In the first zone, the fuel is fired with less than stoichiometric amount of air, creating a fuel-rich condition near the primary flame. In the second zone, the rest of the combustion air is introduced to complete the fuel consumption. The deficiency of O2 in the first zone and the low temperature in the second zone both contribute to a reduction in NO
Sulfur compounds in the synthesis gas stream are converted to SO2 and SO3 during combustion. These two gases are major components of acid rain. For many chemical applications (ammonia synthesis, methanol synthesis, Fischer Tropsch, gas shift,
Sulfur in plants is mainly assimilated by the roots in the form of inorganic sulfate. It is then transported to the leaves where it reduced into sulfite, then into sulfide. Sulfide will further combine with organic molecules to form cysteine or methionine which are amino acids from which proteins are formed [
The mechanisms of release of sulfur species during thermal conversion of solid fuels are influenced by many factors: the type of fuel (coal rank, type of biomass) and the forms of sulfur present in the fuel and the experimental conditions. Sulfur in biomass is found in both organic and inorganic forms. It is generally accepted that the stability of organically-bound sulfur in biomass is low, resulting in its decomposition at lower temperatures (673 K) during the devolatilization. Due to their high stabilities, the inorganic sulfates will not be released during the devolatilization stage. The plant growth conditions, species, and the overall sulfur availability during growth dictates the sulfur content as well as the ratio between organic and inorganic sulfur. Unlike chlorine (Cl) and K, sulfur removal by pretreatment processes like aqueous leaching will only take out the sulfur not organically bound to the structure of the plant [
Some trace elements found in biomass fuels dictate the reaction mechanisms involving thermal decomposition of sulfur. Among these elements, K, Ca, Cl and silicon (Si) have the most significant effect. A better understanding of these elements' inclusion in the plant is necessary to gain a strong insight on how sulfur will behave. Annual biomass usually has a high amount of K and Cl [
Thermodynamic equilibrium of biomass pyrolysis (
Cl is released in two steps: during pyrolysis at temperatures as low as 773 K in the form of HCl and during char burnout at temperatures higher than 973 K in the form of KCl and NaCl [
Si in coal however, might behave differently as it can have a beneficial effect on the sulfur retention at high temperature. In this case, Si may physically enwrap sulfates of lower thermal stability and prevent the dissociation [
In coal, both organic and inorganic forms of sulfur can be characterized. Inorganic sulfur in coal comprises of pyritic or sulfide sulfur, and sulfate sulfur. Elemental sulfur has also been identified in coal, but its amount is generally negligible. The organic sulfur is bound to the hydrocarbon matrix. This form of sulfur occurs in covalently bonded C–S compounds (thiophenes, thioethers and bis-thioethers). Zhao
Many investigations have concluded that coal mineral sulfur could interact with the organic matrix during coal pyrolysis [
One major issue encountered in the thermal conversion of solid fuels is the formation and deposition of ash causing slagging and agglomeration in furnaces and fouling of boiler heat transfer surfaces. Inorganic matters and impurities in coal and biomass contribute to ash formation during thermal conversion; the characteristics of ash formed depend on many factors:
the feedstock category (coal, coke, biomass and waste, variation in a feedstock category:
the type of coal dictates its ash formation and behavior [ the type of biomass and the part of the plant being used as fuel dictate the amount and characteristics of the ash, e.g., barks, straw, grasses and grain generally have a higher mineral matter content compared to wood [ MSW and sewage sludge usually have a higher content of heavy metals compared to coal and biomass; Reaction conditions (temperature, pressure), atmosphere (oxidizing, reducing), flow dynamics [
the feedstock category (coal, coke, biomass and waste,
variation in a feedstock category:
the type of coal dictates its ash formation and behavior [ the type of biomass and the part of the plant being used as fuel dictate the amount and characteristics of the ash, e.g., barks, straw, grasses and grain generally have a higher mineral matter content compared to wood [ MSW and sewage sludge usually have a higher content of heavy metals compared to coal and biomass;
the type of coal dictates its ash formation and behavior [
the type of biomass and the part of the plant being used as fuel dictate the amount and characteristics of the ash, e.g., barks, straw, grasses and grain generally have a higher mineral matter content compared to wood [
MSW and sewage sludge usually have a higher content of heavy metals compared to coal and biomass;
Reaction conditions (temperature, pressure), atmosphere (oxidizing, reducing), flow dynamics [
Biomass mineral matter is usually rich in AAEM and low in alumino-silicates, whereas the content of alumino-silicates is higher in coal. Because of the low melting temperature of AAEM and high melting temperature of alumino-silicates metals, biomass ash tend to melt at lower temperatures than coal ash. It's therefore important to know the behavior of the ash mixture from coal and biomass in the design of co-gasification systems. The wide variation of mineral matter content and quality observed in biomasses as well as in coals causes the design of co-gasification systems to be regarded on a case-by-case basis. There is a need for models of predicting the formation and characteristics of coal-biomass ash mixtures under different gasification conditions.
There is a large amount of literature on the behavior of coal ash [
Investigating the behavior of coal and biomass blend's ash during co-gasification requires starting with an understanding of the different forms of mineral matters present in coal and biomass fuels, the possible chemical reactions they can undergo under a given temperature, pressure and gaseous atmosphere.
Mineral matter in solid fuels is generally grouped into two factions:
The inherent inorganic material, which exists as part of the organic structure of the fuel, and is most commonly associated with the oxygen, sulfur and nitrogen-containing functional groups. These organic functional groups can provide suitable sites for the inorganic species to be associated chemically in the form of cations or chelates. Biomass materials tend to be relatively rich in oxygen-containing functional groups, and a significant fraction of the inorganic material in some of the lower ash biomass fuels is commonly in this form. It is also possible for inorganic species to be present in very fine particulate form within the organic structure of some of the fuels, and to behave essentially as an inherent component of the fuel. The extraneous inorganic material, which has been added to the fuel through geological processes or during harvesting, handling and processing of the fuel. Biomass fuels, for instance, are commonly contaminated with soil and other materials, which have become mixed with the fuel during collection, handling and storage [
The inherent inorganic material, which exists as part of the organic structure of the fuel, and is most commonly associated with the oxygen, sulfur and nitrogen-containing functional groups. These organic functional groups can provide suitable sites for the inorganic species to be associated chemically in the form of cations or chelates. Biomass materials tend to be relatively rich in oxygen-containing functional groups, and a significant fraction of the inorganic material in some of the lower ash biomass fuels is commonly in this form. It is also possible for inorganic species to be present in very fine particulate form within the organic structure of some of the fuels, and to behave essentially as an inherent component of the fuel.
The extraneous inorganic material, which has been added to the fuel through geological processes or during harvesting, handling and processing of the fuel. Biomass fuels, for instance, are commonly contaminated with soil and other materials, which have become mixed with the fuel during collection, handling and storage [
The inherent inorganic materials in biomass fuels can further be categorized as:
water soluble, that is in free ionic form; organically associated; precipitated as relatively pure compounds, in crystalline or amorphous forms [
water soluble, that is in free ionic form;
organically associated;
precipitated as relatively pure compounds, in crystalline or amorphous forms [
Many laboratory characterization techniques for biomass ashes have been adapted from coal studies, e.g., the chemical fractionation technique; this technique is based on the solubility of the fuel subjected to successive leaching with increasing severity (water, ammonium acetate and hydrochloric acid) of the chemical reagents [ water leachable fractions consisting mainly of alkali metal salts, sulfur and chlorine compounds; buffer solution leachable fractions, usually associated to the organic matrix; acid leachable fractions, containing mainly carbonates and sulfates; the residue fraction is mainly silicates and other species not soluble in mineral acids.
water leachable fractions consisting mainly of alkali metal salts, sulfur and chlorine compounds;
buffer solution leachable fractions, usually associated to the organic matrix;
acid leachable fractions, containing mainly carbonates and sulfates;
the residue fraction is mainly silicates and other species not soluble in mineral acids.
The water and acetate-leachable elements are usually considered as those that are readily vaporized, forming the very finest aerosol fraction of the ash generated. The acid-soluble and residue fractions are not considered to be easily vaporized, therefore, they tend to be the major constituents of the coarser fractions of the ash [
Vaporization, condensation and coagulation/agglomeration are the main mechanisms involving biomass ash formation; alkali metals and chlorides contained in biomass vaporize to form HCl(g), KCl(g), K2SO4(g), Na2SO4(g), and NaCl(g) [
The inherent and extraneous inorganic materials of coal have different pathways for ash formation. Inherent inorganic materials are close to each other in the char particle; therefore, they become molten and easily coalesce and agglomerate during char burnout. Extraneous minerals mainly form ash through fragmentation, a mechanism that seldom occurs in inherent mineral matters [
Another important characterization technique is the slagging and fouling index, first developed to study the thermal behavior of coal ash, and modified for studying other solid fuels, including biomass. Many authors have developed indices for slagging and fouling; most of these indices are based on the fuel ash content and/or the ash chemical composition. They give an indication of how a fuel is inclined to forming deposits in the gasifier.
Chemical equilibrium calculation has been used in many studies to predict the behavior of ash at given pressures and temperatures. As stated earlier, because of the lack of co-gasification studies on ash characteristics, almost all the literatures explored here are from co-combustion. We also mentioned earlier that behavior of ash from co-gasification of coal and biomass has to be investigated on a case-by-case basis, given the wide variation in coal fuels as well as biomass fuels. Most of the studies involving co-firing coal and straw have focused on the speciation of alkali metals and the reactions of alkali metal with chlorine to determine the properties of fly ash deposits [
Unlike combustion (and co-combustion) fly ash, gasification (and co-gasification) ash contains a high concentration of unburned carbon and harmful soluble compounds, making it unsuitable for direct use in most combustion ash utilization methods [
Extraction of biomass from farmland or forest removes nutrients and acid-buffering capacity from the soil. N, phosphorus (P) and K are the main elements present in a complete fertilizer. Nitrogen in the gasification feedstock is generally released as ammonia, amines, and urea in the volatiles during the gasification process and only a negligible amount remains in the ash. Since ash from thermal processes are nearly deprived of nitrogen while P is present in a form which is poorly soluble at soil conditions, utilization of combustion and gasification ashes in all-purpose fertilizer is limited [
Coal fired fly ash has pozzolanic properties; it can react with lime to form a hardened mass. The particle shape, fineness, chemistry and pozzolanic reactivity of fly ash provide a low permeability when used in concrete, improving the long term strength gain, durability and reduced shrinkage [
Bottom ash is the easiest for utilization as building material. Bottom ash from fluidized bed combustion or gasification consist for a large part of sand and may replace other kinds of sand in road base and sub-base aggregate, use as structural fill material, and as fine aggregate in asphalt paving. Bottom ashes from grate stokers and entrained-flow gasification can be made into granulate and find its way to road constructions and concrete. Other applications of bottom ash include snow and ice control, as aggregate in lightweight concrete masonry units, and raw feed material for the production of Portland cement [
In the preceding, we have explored the current status of coal and biomass co-conversion in thermochemical systems. It has been noted that this process allows for compensating the shortcomings of one fuel by another, since both fuels seems to be complementary in their drawbacks and advantages.
GHG mitigation is one of the most attractive benefits of co-converting coal and biomass. Although lifecycle assessments of co-gasification processes are scarce, lifecycle assessment on co-firing coal and biomass have shown that CO2 emission declines proportionally to the amount of coal offset by biomass, considering biomass as a carbon-neutral source produced sustainably [
Entrained flow gasification produces a relatively clean gas compared to fixed bed and fluidized bed gasification. However, size reduction of biomass to the order of hundreds of μm, required in entrained flow systems, is difficult to achieve, requiring preprocessing steps like torrefaction or fast pyrolysis.
Catalytic gasification of coal by AAEM is well documented in the literature [
There is no common agreement regarding the synergistic effect of coal and biomass in the literature. Those authors favoring interaction between coal and biomass have suggested that free radicals formation and hydrogen transfer from biomass to coal could be the key explanation behind this phenomenon. Temperature dependence of the synergy has also been mentioned, with prominent synergy at lower temperature up to an optimum above which no synergy is noticeable [
Thermodynamic equilibrium of co-gasification shows that the amount of gases increases as the percentage of biomass in the blend increases, increasing the gross calorific value and coal gas efficiency of the gas. Increasing the reaction temperature favors endothermic reactions; formation of CO and H2 are thus enhanced while the fractions of CO2 and H2O in the gas are reduced. Meanwhile, the cold gas efficiency and the gross calorific value increase up to an optimum temperature above which they begin to decrease. Increasing the pressure has an opposite effect to that of temperature with an increase in CO2, H2O, and CH4 while CO and H2 are reduced. This leads to a decrease of the cold gas efficiency and gross calorific value; however at higher temperatures, the effect of pressure is eclipsed by that of temperature.
Biomass mineral matter is usually rich in AAEM and low in alumino-silicates, whereas the content of alumino-silicates is higher in coal. Because of the low melting temperature of AAEM and high melting temperature of alumino-silicates metals, biomass ash tend to melt at lower temperatures than coal ash. It's therefore important to know the behavior of the ash mixture from coal and biomass in the design of thermal co-conversion systems. The wide variation of mineral matter content and quality observed in biomasses as well as in coals causes the design of co-conversion systems to be regarded at a case-by-case basis. There is a need for models of predicting the formation and characteristics of coal-biomass ash mixtures under different gasification conditions.
The formation, behavior, and use of ash under combustion conditions for coal [
Among all renewable energies, biomass is the only source of concentrated carbon and as such, is the only renewable energy source for replacement of transportation fuels, and therefore, will certainly play an important role in meeting the future energy need of the world. The share of biofuel in the transportation fuel market is likely to grow rapidly in the next decade due to numerous benefits, including sustainability, reduction of GHG emissions, regional development, reduction of rural poverty and energy security. Coal gasification is a proven technology that has been operated successfully at commercial scale for heat, power generation and synthetic fuels; some commercial applications of biomass gasification for heat and power are also available. However, biomass gasification and subsequent production of synthetic fuels (diesel fuel, methanol and dimethylether,
This technical work was performed with partial support National Energy Technology Laboratory under the RES contract DE-FE0004000.
The authors declare no conflict of interest.
Illustration of the liquefaction process [
Results of volatile yields as a function of pressure from different authors [
Thermodynamic equilibrium distribution of sulfur and potassium (K) during pyrolysis in nitrogen [
Equilibrium distribution of main S forms during pyrolysis of wheat straw in nitrogen with Ca and K silicates omitted [


text:
The Tyrone side had the first-half wind advantage but Ballinderry were more dangerous in attack as the teams went in 0-5 to 0-5 at the break.
Ballinderry moved two points clear but Errigal fought back to level.
Conleth Gilligan restored Ballinderry's lead only for Canavan's free to force a replay at Casement next Sunday.
There was never more than one point between the teams until a Enda Muldoon free gave Ballinderry a two-point cushion early in the second half.
Errigal, despite having the wind in their faces, restored parity at 0-9 to 0-9 thanks to Owen Gormley's fourth point of the game.
Gilligan's fifth point edged the Derry men ahead again early in injury-time and it seemed it would be enough to secure the win.
However, Errigal won a free in the final attack of the game and after referee Seamus McGonigle twice moved the free forward it presented Canavan with a straightforward chance to equalise.
Errigal centre half-forward Pascal Canavan praised the spirit in the team.
"I suppose it's been the mark of the team a few times this year that when we've been up against it we seem to get the answer from somewhere," he said.
"We hung in there and are thankful to be still in it.
"Next Sunday is another day and whatever's went in the past will mean for nothing."


text:
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