Process industries produce products that many people can use, but they also yield pollution to the environment. This paper focuses on the significance of sustainable development and processes that are environmentally friendly and integrate the role of green engineering in designing these processes. Green process engineering defines the development of new technologies that reduce pollution generated by the industries. Engineers and researchers are working to develop new methods to confront environmental issues and non-sustainable behavior of current processes in the industrial world.
Introduction
Consumers need products for their daily life use, and it is impossible to live without certain products. These products are manufactured in different industries. The industries have designed processes that generate toxic gases and by-products which is harmful for human health and the environment. These processes need to be developed or new processes should be designed to achieve sustainability. Green process engineering (GPE) is a new field to promote these kinds of innovations. The focus of GPE is to design, commercialization, and use of processes and products that minimize pollution, promote sustainability, and protect human health (Agency, 2019).
In the past, the main purpose of process industries was to develop a process that will cost less and produce more products. Currently and in the future, the goal of process industries is to develop new ideas and re-design processes that would increase productivity with less environmental impact, keeping the market values in consideration. Scientists and researchers are working achieve the above goals. In other words, today’s process engineering has moved towards the green process engineering(Patel, Kellici, & Saha, 2014). To totally achieve a sustainable process, some other factors including suitable market conditions, effective economical regulations and social acceptance should be considered.
The principles of Green Engineering provide a definite outline to address the growing concern of the environment and provide a suitable guide for green process engineering. The United States Environmental Protection Agency has defined nine principles of Green Engineering. (Tang, Bourne, Smith, & Poliakoff, 2008) have presented 24 principles with the mnemonic of PRODUCTIVELY and IMPROVEMENTS for Green Chemistry and Green Chemical Engineering respectively (Patel, Kellici, & Saha, 2014).
The UK Engineering and Physical Sciences Research Council (EPSRC) announced four projects in 2012 that will help to achieve sustainability (Patel, Kellici, & Saha, 2014). These projects are: (i) CLEVER (Closed Loop Emotionally Valuable E-waste Recovery); (ii) (CL4W) Cleaning Land for Wealth; (iii) EXHUME (efficient X-sector use for Heterogeneous Materials); and (iv) CORE (Creative Outreach for Resource Efficiency).
Green Engineering application can be applied to every industry. These applications can be grouped into the following categories: Renewable energy (Diwekar, 2003), process optimization (Liu, Li, Ma, & Cheng, 2010) , environmental monitoring and the development of green products and technologies (Jenck, Agterberg, & Droescher, 2004). This paper focuses on green processes, analyses how it is used in industries and highlight the challenges faced by industries. A brief review of important processes has been discussed in the next section.
Literature Review
Whether it is a simple laboratory process or an industrial level process, the impact of processes on environment and human health should be taken in consideration. To reduce the impact of non-sustainable process, companies are striving to achieve sustainable processes that would fulfil the demand of people and will have less influence on the environment. This section illustrates some effective work performed that will clear the concept of green engineering.
Currently, the majority of the world’s energy is supplied through petrochemical sources, coal and natural gas. However, depleting fossil fuels, increasing energy demand from various sectors, global warming, environmental pollution due to the widespread use of fossil fuels and price fluctuations make petroleum-based energy unreliable. Therefore, it is increasingly necessary to develop renewable energy resources to replace the traditional sources. Biodiesel has recently attracted enormous interest as an alternative and environmentally friendly fuel source. Biodiesel exhibits characteristics that are similar to traditional diesel fuel. In addition, the flow and combustion properties of biodiesel are similar to petroleum-based diesel [10]. Biodiesels have the following advantages over diesel fuel: they produce less smoke and particulates, have higher cetane numbers, produce lower carbon monoxide and hydrocarbon emissions, are biodegradable and non-toxic and provide better performances in engine lubricity compared to low sulphur diesel fuels.
Hence, it could be used as a substitute for diesel fuel. Currently, the majority of the world’s energy is supplied through petrochemical sources, coal and natural gas. However, depleting fossil fuels, increasing energy demand from various sectors, global warming, environmental pollution due to the widespread use of fossil fuels and price fluctuations make petroleum-based energy unreliable. Therefore, it is increasingly necessary to develop renewable energy resources to replace the traditional sources. Biodiesel has recently attracted enormous interest as an alternative and environmentally friendly fuel source. Biodiesel exhibits characteristics that are similar to traditional diesel fuel. In addition, the flow and combustion properties of biodiesel are similar to petroleum-based diesel [10]. Biodiesels have the following advantages over diesel fuel: they produce less smoke and particulates, have higher cetane numbers, produce lower carbon monoxide and hydrocarbon emissions, are biodegradable and non-toxic and provide better performances in engine lubricity compared to low Sulphur diesel fuels.
The emission of carbon dioxide (CO2) to the atmosphere has led to climate change. It is a global environmental challenge to overcome this problem. Organic carbonates like propylene carbonates (PC) and dimethyl carbonates (DMC) have been used as an intermediate in the synthesis of chemicals, pharmaceuticals and fuel additives (Patel, Kellici, & Saha, 2014). These organics carbonates are prepared using homogeneous catalysts, toxic raw materials, and solvents. There is a need for processes that will synthesis organic carbonates that will be environmentally friendly, by eliminating the use of toxic chemicals and solvents. One better way is the synthesis of organic carbonates from CO2 using heterogenous catalysts.
Petrochemicals, coal and natural gas are the main sources of energy production in the current era. The emission of carbon dioxide (CO2), carbon monoxide (CO), hydrogen sulphide (H2S), and other toxic gases make these resources unreliable. Biodiesel and biofuel are the alternate fuel sources. The properties of biodiesel are almost similar to petroleum diesel.
(Abbaszaadeh, Ghobadian, Omidkhah, & Najafi, 2012) have discussed few technologies for the production of biodiesel. The best method for the production is the transesterification of triglycerides. Used cooking oil is considered to be the best attractive feedstock for biodiesel production. The first- and second-generation biofuels have some drawbacks. To eliminate these problems, the third-generation biofuels, such as microalgal oil, is regarded as the best way for biodiesel production. A number of publications have reported the production of biodiesel from algal oil using a two-step process, i.e., acid esterification followed by transesterification. Using this process, 90.6% yield of biodiesel was achieved at optimum conditions using Enteromorpha Compressa algal oil (Patel, Kellici, & Saha, 2014). While 100% conversion was achieved using Scenedesmus algal oil.
Biodiesels have some limitations as compared to petroleum-based diesel, such as tendency to gel at low temperature, low volatility and incomplete combustion. Nevertheless, scientists and engineers are working hard to fulfil the needs of future fuel demand.
References
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Adeleye, A. I., Patel, D., Niyogi, D., & Saha, B. (2014). An Efficient and greener synthesis of propylene carbonate from carbon dioxide and propylene oxide. Green Engineering.
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