Chemical Engineering and Clean Technology : New Reactor Types

CHEMICAL ENGINEERING AND CLEAN TECHNOLOGY WORKSHOP:

NEW REACTOR TYPES

The chemical sector has long been seen being socially dangerous and “dirty”. Increased global competition has forced industry to look at green routes for achieving efficient manufacturing processes. Since the 21st century, significant amounts of research have been carried out into the development of sustainable and environmentally friendly techniques for chemical synthesis, with the main goal being the reduction of waste generated by the chemical industry. [1]

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The reactor is often seen and described as the “heart” of chemical processes. Downstream processes are a function of the reactor performance, particularly in such features as degree of control, selectivity and heat and mass transfer. Moreover, the upstream processes can be regarded as a series of steps with the only objective to get the reactants to the best possible condition for input to the reactor.

Flow chemistry and continuous processing can offer many ways to make synthesis a more sustainable procedure. These technologies provide significant improvements in mixing and heat management, scalability, energy efficiency, waste generation, safety, access to a wider range of reaction conditions, and unique potentials in heterogeneous catalysis and multistep synthesis. [2]

In this regard, a type of reactor that is becoming increasingly of interest is the membrane flow reactor. In this apparatus, the membrane could have multiple functionalities, it can work as a separator for recovering reaction products in situ, or for catalyst recovery. As for most other separation techniques the key feature of membrane reactors is their ability to take reactions to completion by continuous product removal.

Many types of membrane reactors have been developed and tested in the last two decades. One form of membrane reactor which is attracting attention, even if proposed in 2003, is the tubular inorganic catalytic membrane (TICM) described by Centi et al. Its applications range from refinery uses to environmental protection. Lower pressure operation, allowed by the possibility of putting the catalyst into the membrane pores, combined with better three-phase contact in comparison with other reactors, leads to higher selectivity and yield. The reduction of nitrates or nitrites in water using a tubular membrane reactor configuration (Fig. 1), was also described by Centi et al. (2003). Furthermore, their study showed that the membranes could be regenerated intermittently by removing them from the reactor, calcining and pre-reducing with helium/hydrogen, and once reintroduced, the membranes were essentially immaculate.

Fig 1. Configuration of a tubular inorganic catalytic membrane reactor module (Centi et al., 2003) [3]

Among membrane reactors, gas–liquid–solid (GLS) and liquid–solid (LS) type slurry reactors are widely used in the chemical, fine chemical and pharmaceutical industries. Applications include hydrogenation, condensation, esterification and enzymatic conversion processes. In these slurry processes the catalysts must be recovered externally from the reaction mixture. This filtration step is not beneficial for the process, it does often lead to catalyst attrition and deactivation, as well as operation and handling problems. Moreover, attrition of catalyst particles can cause loss of catalyst particles and emissions to the environment. Inefficient use of the catalyst, combined with extensive residence time distributions, can lead to undesired by-products.

A membrane slurry reactor would be a solution to these drawbacks. In the membrane slurry reactor concept, improved control of process conditions and a more efficient use of the catalyst are guaranteed by membranes and heat exchanger tubes, which allows separation and heat transfer within the chemical reactor. A main advantage is, however, that the membrane slurry reactor can bring the use of more selective catalysts (enzymes) and subsequent selective product recovery, leading to higher conversions, reduction of the amounts of by-products and emissions and optimisation of the quality of the main product. The membrane slurry reactor therefore takes an important step towards a more sustainable, green chemical industry.

Heat exchanger tubes and hollow fibre membranes located within the reactor allow the removal of reactants and products from the system.                                                                                          Remarkably, the use of a membrane reactor for the enzymatic hydrolysis of casein has been reported by Trusek-Holownia (2008). [3]

 

A more recent work, shows the development of a scalable, safe and sustainable thin-layer membrane reactor for homogenous Cu(I)/TEMPO alcohol oxidations and heterogeneous Pd-catalysed hydrogenations by Mo et al.                                                                                                          This is particularly interesting since among numerous pharmaceutical transformations, gas–liquid reactions (e.g. aerobic oxidation and hydrogenation) show appealing atom economy in comparison to other chemical transformations. Furthermore, the overall availability of gaseous reagents and simple downstream separation make gas–liquid reactions potential green chemistry processes. However, concerns of process efficiency, scalability and safety of gas–liquid systems limit their use for pharmaceutical applications, and this becomes even more challenging when heterogeneous catalysts are involved. The safety profiles are though significantly improved when gas-liquid reactions are carried out in continuous flow reactors, where there is no high-pressured gas in the headspace and the reactor volume is contained. In addition, the increased interfacial area per volume in flow reactors accelerates multiphase mass transfer rates.                                                                                                     The continuous reactor developed by Mo et al uses a Teflon AF membrane, inserted between two sheets of thin-layer carbon cloth (Fig. 2a), which enables superior gas–liquid mass transfer performance. The carbon cloth layer works as a heterogeneous catalyst support, making this reactor design applicable for heterogeneous catalytic gas–liquid reactions. Additionally, most of the gas is consumed during the reaction, removing the need for recycle and enhancing the safety of the process by minimizing the amount of gas required. Another important feature to underline is that the membrane reactor is also stackable, allowing for scale-up. [4]                                                                                                                                           

Fig. 2 (a) Gas–liquid membrane reactor schematics. (b) Exploded-view CAD drawing of the gas–liquid membrane reactor. Two thin black layers are carbon cloth; the blue layer is a Teflon AF membrane. (c) Photograph of assembled single-layer membrane reactor. [4]

The main advantage of using a Teflon AF membrane is related to its high permeability to the only gas phase, which enables the separation of the two different phases while allowing gas to diffuse through the membrane into the liquid phase. Moreover, the design of the reactor was planned to minimize the thickness of the combined assembly (carbon cloth: 300 µm and Teflon AF membrane: 40 µm) in order to improve the mass transfer phenomena. In addition, this reactor can handle high pressure operation (tested up to 3.1 MPa), improving the solubility of H2 in the organic solvent and therefore intensifying the hydrogenation process. For the study reported, the membrane reactor (Fig. 2b and c) was fabricated out of aluminium, due to the inferior cost of the material. To achieve higher chemical compatibilities, the reactor could also be coated with perfluoro alkoxy alkane (PFA) or fabricated out of stainless steel. The internal temperature is controlled by cartridge heaters combined with a proportional–integral–derivative (PID) temperature controller.                                For the system maintenance, it is necessary to rinse the reactor liquid side with appropriate solvent and the gas side with nitrogen, before the beginning of a new procedure. Once the reagents are introduced into the reactor, the gas side must be pressurized while maintaining a low (∼150 kPa) transmembrane pressure with the back-pressure regulator (BPR) on the liquid section, which is required to prevent the passage of the gas through the BPR and the disruption of the membrane.

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Pt and Pd heterogeneous catalysts appeared both to be good alternatives for hydrogenations reactions, but experiments proved the former to be too aggressive, leading to the formation of by-products, while Pd showed a better selectivity towards the desired product. Once optimized the reaction conditions, the membrane reactor has been used to carry out numerous hydrogenations with different substrates, proving itself to be efficient. [4]

Aerobic oxidation reactions could be an attractive alternative to conventional approaches employing stoichiometric oxidants. However, the concrete use of aerobic oxidation in large-scale synthesis advances safety concerns, i.e. the formation of explosive mixtures (flammable organic solvents in oxygen). Micro-structured flow reactors are currently used for aerobic oxidations, because of the intrinsic safety of their microchannels. However, the explosive mixture is still present. Tube-in-tube membrane reactors show great potential to avoid the formation of this dangerous mixtures, but still have inherent scalability issues for large-scale synthesis. Implementing the thin-layer membrane reactor designed by Mo et al. offers the opportunity to make aerobic oxidation reactions both safe and scalable for industrial applications. Instead of using a catalyst-embedded carbon cloth layer, virgin carbon cloth was installed in the membrane reactor, along with the same Teflon AF membrane to accommodate the homogeneous catalytic (Cu/TEMPO) aerobic oxidation. Meanwhile, the Teflon AF membrane separates the oxygen and organic solvent to circumvent the formation of explosive mixtures. Many substrates were examined in the membrane reactor with optimized conditions, and all products were achieved in excellent yields.

The residence times required to reach full conversion were around 1 min, significantly shorter than the several-hour reaction times required under batch conditions. Furthermore, the capability to handle high pressures in the membrane reactor would intensify this reaction by orders of magnitude compared to batch processing.

In trickle-bed or packed-bed reactors the scale-up process is particularly problematic due to the change in multiphase hydrodynamics, mass and heat transfer properties within different scales. The simplified fluid hydrodynamics in the thin-layer membrane reactor allows for straightforward scale-up with a stackable design. The stackable design maintains a fixed heat and mass transfer distance (carbon cloth thickness) while increasing the reactor size laterally and in parallel, leading to preserved heat and mass transfer advantages of the single-layer membrane reactor while meeting the required productivity. As shown in Fig. 3, the main channels of a 3-layer stacked membrane reactor distribute or collect gas streams and liquid streams into or from each layer. [4]

Fig 3. Cross-section of the inlet channels in a 3-layer stacked membrane reactor with blue arrows indicating the liquid flow and purple arrows indicating the gas flow. The outlet channels collect flow from each layer with reversed arrow directions.

In conclusion membrane reactors properties make them in general an interesting type of reactors to work with and on in the future. For example, their high surface to volume ratio guarantees higher reaction rates, reaction and separation can occur in one step reducing the overall cost and the presence of less stagnant zones gives a good catalyst reactivation, therefore membrane reactors are to consider as a sustainable and greener option compared to other reactor types currently used in industry.

The Teflon AF membrane reactor is of certain interest since both the membrane design and the guidelines for safe operation of oxygenation reactions provided by Mo et al. could potentially speed up the implementation of oxygen and hydrogen as cheap, green reagents in industrial chemical applications. In comparison to other membrane reactors the thin layer design maximized mass transfer in gas-liquid systems and simplified the multiphase hydrodynamics for liable reactor performance and scale-up. Moreover, optimizing the carbon cloth thickness according to the reaction kinetics balanced the trade-off between reactor manufacturing cost and productivity. [4]

REFERENCES

[1] C. Wiles and P. Watts, Green Chem., 2012, 14, 38-54

[2] S. Newman and K. Jensen, Green Chemistry, 2013, 15, 1456

[3] D. Reay, C. Ramshaw and A. Harvey, Process Intensification, 2013, 121-204

[4] Y. Mo, J. Imbrogno, H. Zhang and K. Jensen, Green Chemistry, 2018, 20, 3867-3874

Clean Food Health

The issues surrounding the laws of clean and unclean food have been heavily debated within the Judea/Christian circles for a long period of time. ‘Why should God be concerned about what we eat? The purpose of my research is to attempt to understand why these laws were set within the Old Testament and to compare and contrast different scholarly approaches to this very interesting topic.

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Many have reviewed the dietary laws within Leviticus and Deuteronomy, questioning whether they were relevant to a certain nations? For example, Israel, tending to lean to an opinion that the laws were set within the Old Testament, and were obsolete at the point of the New Testament? Some argue that these laws are still applicable today whilst others oppose and question there relevance in today’s society.
My aim and methodology is to review the primary sources available within this area found in the Old Testament and review the evidence that supports the rationale behind these dietary laws. I will attempt to analyse and compare the evidence taken by selected scholars from various backgrounds, such as, anthropologists, ministers and professors, all who have credible background to share on this topic. I have grouped their views into the following three categories; Health/Hygiene, Symbolic/Holiness and Ritual Purification.
The word unclean is defined as ‘dirty, immoral, unchaste’ to be clean would imply the opposite definition. When we look closely and analyse the term clean and unclean within the Old Testament Bible, scholars have varied meanings and approaches to this law.
Health/Hygiene
Health ‘is a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity’ When we apply good health our bodies are naturally in good shape. Health and Hygiene are closely linked and go hand in hand together. ‘Hygiene is the maintenance of health and healthy living’. Covering many areas such as diet, personal, domestic, public and mental cleanliness.
The following scholars support the view that health and hygiene has a significant role within the dietary laws, Jacob Milgrom, RK Harrison, and John Brunt.
All have commented in particular to the Pig, with a view that this animal carries a disease known as Trichinosis. Trichinosis is a parasite worm that lives in the flesh of pig meat, and is passed on when pig flesh is under cooked, and can grow into a considerable size within the intestine. The Hare carries tularaemia which is an acute infection resembling the plague, but not as severe. Scavenger birds, known as Carrion birds also carry disease, and fish with out scales and fins attract disease because they search for food in the mud.
Milgrom argues that a camel is a forbidden animal to eat according to the dietary laws ‘yet there is no evidence to support that this animal poses a threat to health or is unhygienic’. He also argues why just animals have been prohibited, as there are poisonous plants that are unhygienic and can be very harmful to the health of a human if eaten. This point highlights a weakness in the dietary laws.
Harrison argues that ‘the separation of clean from unclean meats should not be taken to imply that the true ruminants are completely free from parasitic organisms’. Harrison also uses further examples with regard to the Ox, which is a clean animal, but is also prone to transmit parasites.
Brunt argues that ‘we accept aspects of the teachings concerning what to eat, but do not follow through, for example when we touch an unclean insect we should wash our clothes’.
Symbolic/Holiness
Symbolism ‘is the systematic or creative use of arbitrary symbols as abstracted representations of concepts or objects and the distinct relationships in between, as they define both context and the narrower definition of terms’.
Holiness is ‘the state of being holy, that is, set apart for the worship or service of God or gods. It is most usually ascribed to people, but can be and often is ascribed to objects, times, or places’.
The following scholars support the view that symbolic and holiness has a significant role within the dietary laws, Jacob Milgrom, G J Wenham, Gerald F Hasel and Lester L Grabbe.
The observance of the dietary laws could be seen as symbolic. God’s people have been set aside from the other nations to be an example, by observing dietary laws. This would mean that here would be a clear distinction between the Israelites and the other nations.
Milgrom states that ‘the diet laws have been implied by the concept of holiness’.
Wenham makes it very clear that ‘the diet laws were given in a specific situation to a specific situation to a specific period, they are part of the blueprint for making the people of Israel holy’Hasel refers to the observance of dietary laws ‘it is a holy people that continues to make a distinction between the clean animal and unclean’.
Grabbe states that ‘the dietary regulations had both a practical and symbolic function, symbolically they stood for the fact that Israel was to keep itself free from intercourse with non- Israelites’.
Ritual Purification
This is that ‘the aim of these rituals is to remove uncleanliness, which may be real or symbolic. Most of these rituals were created long before the germ theory of disease. Some religions have special treatment of particular body fluids such as semen and menses which are viewed as particularly unclean’.
Ritual purity during this period was an essential part of life to the people of Israel.
This prepared each individual to ensure that they were clean before they entered into the sanctuary to worship God. The following scholars support the view that ritual purification has a significant role within the dietary laws, Mary Douglas, John E Hartley, and John Brunt
Douglass states that ‘the impurity of an animal kind is part of the technical meaning of ritual purity’. Douglass also adds ‘ritual impurity imposes Gods order on his creation’ Hartley states that ‘the main purpose for the purity instructions was to keep the Israelites separate from the neighbouring nations in order to promote Gods call for Israel to be a holy nation’.Brunt states that ‘the New Testament rejects the distinction between clean and unclean, it is not speaking to the issue of health, it is rather addressing problems that were live issues in the 1st century, problems of ritualism and exclusivism’. Brunt argues that ‘for the Christian, all things are clean, true spirituality is a matter of the heart, not of ritualistic externals’.
Conclusion
The dietary laws debate will continue for many more years. However I have found this research very refreshing to review approaches of this topic from scholars who are not Seventh Day Adventists, from various backgrounds.
We can see from the categories where some scholars hold or share the same view and differ from each others in different areas. The most common theme that came out within the dietary laws and findings in most of the scholars approaches was the point regarding the eating of pork. Most appear to agree on the fact that this animal is prone to parasites, and depending on the way the meat is prepared it will be good for consumption.
This point came across very strongly among many of the arguments, arguing that even if the meat is heated well, it still does not rid the parasites and others oppose.
In November 2005, The National Geographic produced a documentary on longevity and featured an island in Okinawa, with the longest living people in the world, who accredited this to a soup dish made of pork skin which was boiled at a high temperature in preparation. Based on this finding, we can see that if meat is prepared well it can aid our health, although there may be additional factors that aid to their long life.
The dietary laws in the Old Testament would appear to specifically be relating to Israel – God’s chosen people, whether they are still relevant to modern day is a matter worth deeper research. The New Testament appears to have abolished the laws of ritual purity, Jesus reached out to all nations, Jews and Gentiles removing all barriers, and we find instances of this throughout the whole of the New Testament. This is something that I would like to research more in the future.
 

US Policies to Develop Clean Air

 During the 1950s and 1960s, air quality in the United States was slowly becoming worse and worse. In 1955, epidemiological studies exhibited an increase in smog-related illnesses and deaths that grabbed national attention to pass the first clean air act (“A look back at first US air pollution legislation”, 2014). The Air Pollution Control Act of 1955 acted as a research program conducted by the Public Health Service in an attempt to control air pollution (Ametsoc.org). Although this legislation did not regulate any air pollutants, this act served as the stepping stone that allowed the federal government to recognize the detrimental effects of air pollution. Since the 1950s, there has been a shift in focus on identifying the air pollutants, trying to eliminate or decrease them, and the consequences of air pollution on our planet.

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 Los Angeles became distinguished by he yellowish-brown cloud produced by motor vehicle exhaust in the 1950s (“Introduction to Public Health”, 2017). The Clean Air Act of 1963 recognized the dangers of motor vehicle exhaust, high sulfur coal and oil. Over a three year period, this act funded $95 million to governments and air pollution control agencies to conduct research and create control programs that would promote health and welfare to the American citizens. Based on the research from these agencies, there was a development of emissions standards to reduce hydrocarbons and carbon monoxide in order to protect the community from horrible air quality. As a result, carbon monoxide declined by 84 percent due to these emissions standards and there was a decline of 81 percent between 1980 and 2013 due to the encouraged use of technology to remove sulfur from these fuels (“Introduction to Public Health”, 2017). The Clean Air Act of 1970 established stricter air quality standards and set limitations on major air pollutants.

 The Clean Air Act of 1970 established the National Ambient Air Quality Standards and New Source Performance Standards (Ametsoc.org). The Clean Air Act called an action to regulate the criteria air pollutants which are particulates, sulfur dioxide, carbon monoxide, nitrogen oxides, ozone, and lead. Enviroment Protection Agency was able to identify a number of hazardous particles that contaminate the air like asbestos, mercury, beryllium, benzene, vinyl chloride, arsenic, radionuclides, and coke-oven emissions (“Introduction to Public Health”, 2017). A major source of air pollution was due to motor vehicles, so there were efforts to use less polluting alternative fuels, installation of vapor recovery systems, and annual measurements of tailpipe emissions. The Clean Air Act of 1970 reduced emissions of carbon monoxide and ozone- producing chemicals by 90 percent. Another example of the government decreasing industrial sources of pollution was setting an overall emissions goal and decreasing it over the years. Although these air pollution control acts have been established for our safety, there are lobbyists from industrial plants who are trying to dismantle these laws for their own personal gain.

Air pollution is a major contributor to the global effects that have taken place over the years. Because air pollution does not stay contained in one area, it disperses into the atmosphere causing problems in several locations of the world. Acid rain is an example of two air pollutants forming sulfuric and nitric acid. Acid rain damages forests, destroys surfaces of buildings, and turns water unlivable for organisms who pertain there. EPA data displays that regulations on industrial pollutants in the United States have reduced the acidity of rainfall in the Northeast (“Air Pollution”, 2019). The reduction of the ozone layer is another exhibition of the global effects of some air pollutants. International action was required to reduce the production and use of chlorofluorocarbons in order to restabilize the ozone layer. These examples show the consequences of air pollutants and the importance to reduce them to prevent further damage to our communities and our planet.

Over the years, there have been many efforts pushed by the United States government to promote public health by diminishing air pollution. The 1950s demonstrated the poor air quality that existed and encouraged Clean Air Acts to be passed. These legislations have been set in place to try to reduce or eliminate the criteria air pollutants and inhibit the global effects of air pollution. Although there has been an increase in air quality since the 1950s, there are still repercussions that are happening from the air pollutants that are not being surveillanced heavily. It is important for the government to respect the Clean Air Acts for they are the reason that many smog-related illnesses and deaths are not as common.

Works Cited

Nathanson, Jerry A. “Air Pollution.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., 31 Oct. 2018, www.britannica.com/science/air-pollution/The-global-reach-of-air-pollution.

SCHNEIDER, MARY-JANE. INTRODUCTION TO PUBLIC HEALTH. JONES & BARTLETT LEARNING, 2020.

“Legislation.” Clean Air #1, www.ametsoc.org/sloan/cleanair/cleanairlegisl.html.

“A Look Back at First US Air Pollution Legislation.” National Catholic Reporter, 14 July 2014, www.ncronline.org/blogs/eco-catholic/look-back-first-us-air-pollution-legislation

 

The Role of Ethanol in Clean Fuel Advancement

ABSTRACT
In this contemporary world we face many critical challenges. One of the most important challenges that very much concerns the environment is the global warming and depletion of key non- renewable resources. Due to extensive growth in population and the improved standard of living, results an increasing concern that there will be a shortage of energy to heat our homes and power our vehicles. Advances in technology have allowed development of alternate energy sources. Ethanol is a good alternate energy source. Bio-ethanol is widely used bio-fuel for transportation worldwide. Ethanol production from biomass is one way to reduce high consumption and dependency over crude oil and environmental pollution.

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INTRODUCTION
Ethanol and ethanol–gasoline blends have a long history as automotive fuels. As historical data reveals “In 1896, Henry Ford designed his first car, the ‘Quadricycle’ to run on pure ethanol. Then In 1908, ford motor company’s first car, the model T, used ethanol produced from corn as fuel energy”. United states have been using ethanol powered vehicles since early 1900. As per reports “Though, initial efforts to sustain ethanol fuel technology failed, oil supply disruptions and environmental concerns over the use of lead as a gasoline octane booster renewed interest in ethanol in the late 1970s.” [1, John Triandafyllis and Merkouris Gogos]. Ethanol is a renewable, locally delivered alcohol fuel produced using plant material, for example, corn, sugar stick, or grasses. Utilizing ethanol can lessen oil reliance and natural gas outflow. Ethanol is an attractive alternative fuel because it is a renewable bio-based resource and it is oxygenated, thereby providing the potential to reduce particulate emissions in spark ignition engines.
PROPERTIES
According to data, “Ethanol (CH3CH2OH) is a clear, colourless liquid. It is also known as ethyl alcohol, grain alcohol, and EtOH . Ethanol has a high-octane number compared to gasoline, providing premium blending properties.[3, Alternate fuels data center, U.S dept of Energy. USDA’s 2017]”
Ethanol contains less energy per gallon than gasoline fuel, Premium ethanol (98% ethanol) contains about 29% less energy than gasoline per gallon. [4, Meng, L. (2019).]. Ethanol’s impact on fuel economy is dependent on the ethanol content in the fuel and whether an engine is optimized to run on gasoline or ethanol. The viscosity of ethanol is much less than diesel fuel, which is considered as the reason that the ethanol-fuelled compression ignition engines start more quickly than a diesel engine. Ethanol has a lower molecular weight compared to alcohol and is soluble in water. Hence, liquid fraction separation is easier when blended with gasoline.
Performance of an ethanol driven engine shows a 10% increase in efficiency compared to gasoline driven engine. Moreover, Ethanol is highly volatile and required changes to volatility properties during refinery treatments.
ADVANTAGES

Principal Advantages:

Higher latent heat of vaporization
Uniform composition.
Higher flash point.
Very high-octane rating.
No hazardous component.
Higher compression operation of the engine.
Reduced particulate emissions.
Enhanced engine power output and efficiency.
Increased safety during use.

[5,International journal of environmental sciences   Volume 1, No 2 2010.]

Low resource price:

Ethanol can be produced in any country with agricultural capacity, hence fuel resource monopoly is less.

Environmentally friendly:

Major advantage of ethanol over other fuel sources is that it does causes less pollution to the environment with release of less toxic substances after combustion.

Renewable energy:

It is classified as a renewable resource because it’s mainly as a consequence of photosynthesis from fuel crops and biomass.

Reusable by-products:

The two primary by-products that come from ethanol production are DDGs and carbon dioxide. When CO2 capture technologies are applied to ethanol production, it can be used for dry ice creation, cryogenic freezing, and an agent for pneumatic systems. DDGs stands for “dried distillers’ grains” and is used to replace cornmeal or soybean meal in animal food stocks.

Oxygenation:

Ethanol oxygenates the fuel and improves combustion efficiency and reduces CO2 and CO emissions. [6, Daniel Ciolkosz]
DISADVANTAGES
1. Less effective compared to gasoline:Experimental result quotes “It takes up to 1.4 gallons of ethanol to replicate the mileage that 1 gallon of gasoline can provide. Flex-fuel vehicles that can run on E85 fuel have found that their gas mileage rates are over 25% lower, with some models seeing a 30% reduction with city miles”. [7, Crystal Lombardo]
2. Proved to be a corrosive fuel:Ethanol is highly corrosive because it has an ability to absorb water. That makes it difficult to ship the fuel over long distances or store fuel. Because water is absorbed by this fuel, it corrodes the engine parts and fuel tank causing potential damage to a vehicle.
3. Requirement of lot of cropland space:Large areas of forest lands need to be converted to grow fuel sources such as corn fields to meet the growing demand.
5. Altered food production principles:Due to higher price of corn, more farmers look at ethanol as a viable way to make a living. Instead of using their lands to produce food products, they convert over to growing fuel products. As ethanol demands increase, additional farmers will look to convert to the higher paying yields of corn, especially if there are subsidies available for crop loss.
6.  Higher fuel consumption and drains driveability.A major drawback of ethanol blends is the increase in fuel consumption due to the lower calorific value of ethanol compared to gasoline. There are s effects of ethanol blends on vehicle drivability during cold starting conditions. [8]
APPLICATIONS

A transport fuel blended with gasoline fuels or completely replacing them.
A fuel for power generation by thermal combustion at small scale power plants.
A fuel for fuel cells by thermochemical reaction.
A fuel in cogeneration systems.
A feedstock in the chemicals industry.

TECHNOLOGICAL AND LEGISLATIVE CHALLENGES
Ethanol Bio-fuel can only be blended upto 10% with gasoline to achieve better efficiency by increasing octane number of fuels in normal engines. Excess blending results in decrease in fuel economy.
“Replacing only five percent of the nation’s diesel consumption with biodiesel would require diverting approximately 60 percent of today’s soy crops to biodiesel production, which requires large legislative demands to acquire lands to grow crops for fuel production.”
The major boomers leading to increase in ethanol production are:

Surge in crude oil prices

A rise in oil prices naturally leads to an increase in motor fuel prices. Higher oil prices elicit numerous responses from consumers and firms. In the short run, with few alternatives, demand for gasoline tends to be relatively unaffected. Over time, though, higher oil prices spur an increase in demand for alternative fuels and a decline in the quantity of oil demanded.

Government support for production of ethanol

Many governments such as USA and Brazil have supported use of ethanol blended fuel for powering automobiles. The Government rolled out various tax cuts and credits to protect domestic ethanol producers and to generate tax revenue to offset some of the cost of the ethanol tax credits.

Ethanol as fuel additive

MTBE additive used to reduce smog near refineries were replaces by ethanol additives as MTBE was water pollutant. Hence demand for ethanol grew and also price. [9, Kevin L. Kliesen].
PERSONAL THOUGHTS
The properties of ethanol significantly attribute to a requirement for lot of modifications and advancements in production technologies to effectively use ethanol as an alternate fuel in automobile engines. The Engines should be designed optimally to modify temperature and pressure conditions during combustion cycle and to create a suitable environment for its high volatile nature and viscosity properties. The engine technology should also focus on adapting engines for any amount of blended fuels, irrespective of ethanol percentages.
The emerging markets for new range of Flexible Fuel Vehicle (FFV), starting from Volkswagen polo E-Flex to Audi A3 e-power, which have overcome the requirement for a gasoline tank and can run efficiently on E-85 ethanol fuel blend in any conditions. These advancement in technology can provide a platform for more effective use of Ethanol as an alternate fuel. Large croplands requirement can be tackled by minimizing the use of ethanol fuel and relying on solar and electricity produced from biomass.
CONCLUSION
The advantages and disadvantages of ethanol reflects us that a well-regulated system that includes different types of ethanol could be beneficial. In USA and Brazil, with such a heavy reliance on corn-based fuels, the socioeconomic impact of artificially high yield costs, combined with cropland loss for fuel, could increase household food insecurity levels. A greater balance in production methods could restore balance in this area. We also have to look for fuel resources which are more environmentally friendly and require less modifications to present infrastructure in industries. Ethanol fuel technology has the potential to play a major role in the future where clean man-made fuels are the norms.
REFERENCES

The effects of ethanol on internal   combustion engines[John Triandafyllis and Merkouris Gogos].
Journal of Advanced Review on Scientific Research ISSN (online): 2289-7887 | Vol. 21, No.1. Pages 27-42, 2016.
Alternate fuels data center, U.S dept of Energy. USDA’s 2017 – A Life-Cycle Analysis of the Greenhouse Gas Emissions of Corn Based Ethanol.
Meng, L. (2019). Ethanol in Automotive Applications. Ethanol, 289–303. doi:10.1016/b978-0-12-811458-2.00011-0. International journal of environmental sciences   Volume 1, No 2 2010.
Daniel Ciolkosz, Penn State Department of Agricultural and Biological Engineering. Reviewed by Andre Boehman, University of Michigan, and Douglas Schaufler, Penn State Department of Agricultural and Biological Engineering.
rystal Lombardo(Author) https://vittana.org/11-advantages-and-disadvantages-of-ethanol

Advantages and Disadvantages of Ethanol as a Fuel


Kevin L. Kliesen (Author) https://www.stlouisfed.org/publications/regional-economist/july-2008/ethanol-economic-gain-or-drain