Ethanol renewable sources

Ethanol is a nontoxic substance with relatively high H2 content, and its advantage is that it can be produced from renewable sources, for example, from various biomasses and wastes. In addition, purification of the produced reforming gas has been of interest to researchers. Hydrogen purification has been studied, for instance, with membranes [19] which can also have catalytic performances. 

Methanol and ethanol are alcohol fuels that can be produced from various renewable sources. Alcohol fuels are converted from biomass or other feedstocks using one or several conversion techniques. Both government and private research programs are finding more effective, less costly methods of converting biomass to alcohol fuels. Methanol was originally a by-product of charcoal production, but today it is primarily produced from natural gas and can also be made from biomass and coal. 

By 2007, about 4% of all the fuel sold or dispensed to U.S. motorists came from renewable sources, which is almost 5 billion gallons of renewable fuels. New and expanded plants now under construction are expected to push the annual production of ethanol well above this level. 

All these circumstances have lead the industry to begin searching for a new source of energy an alternative and completely petroleum-independent power source. Several technologies are being researched, such as biomass (bio-diesel, ethanol), renewable ocean sources (wave, tidal, and thermal), hydrogen, and many more. 

At present, roughly 80% of the current global energy needs comes from fossil fuels. Besides, oil is used as a raw material for the production of several chemical products. Ethanol (C2H5OH), a natural product obtained from biomass, is, on the one hand, a renewable source of energy that would be an important factor for near-zero carbon dioxide (C02) emissions, on the other hand, it is the basis for a C2 chemistry, that is, a raw material for the production of different chemical products [19,21,137-147], Besides, ethanol is accessible, can be easily transported, biodegradable, has low toxicity, and can be transformed by catalytic reactions [137],... 

Methanol and ethanol have been considered as promising fuels for generating H2, especially for on-board fuel cell applications due to their easy availability, ability to transport, and reaction simplicity.52 121 159 169 For example, both alcohols have high H2-to-carbon ratio (H/C) of 4 and 3, respectively (Table 2.1). They could be synthesized from renewable sources such as biomass and thus the ability to close the carbon cycle.161 166 Unlike hydrocarbon fuels, methanol and ethanol are free from sulfur, and this avoids additional sulfur removal step in the fuel processing. In addition, methanol can be reformed at a lower temperature, around 300 °C, and this makes the fuel processing relatively simple and less complicated. Furthermore, unlike natural gas, which produces primarily syngas, reforming of methanol and ethanol can in principle produce a mixture of H2 and C02, and this would also simplify the downstream CO cleanup for fuel cells such as PEMFCs where CO is a poison. 

Currently, the United States imports about ST/o of its oil, creating a US 66 billion trade deficit the deficit is expected to rise to US 170 billion by 2020.Projections show that oil imports could grow to 68%i in 2025, thus increasing the dependence on crude oil from potentially unstable regions around the world. It is estimated that a 10%i ethanol blend would reduce oil requirements by 3%i, while a 95%i ethanol blend could reduce the oil requirement by as much as 44%). Thus, it is beneficial to increase local energy production via fuels from renewable sources to prevent sudden energy disruptions, which could have severe economic ramifications. 

One of the most abundant natural and renewable sources of carbon is cellulose, fibers that have been used for centuries in the production of paper. Chemists have found ways to modify these water-insoluble fibers, applying various chemical or biochemical treatments that generate high value materials (modified cellulose). The latter find applications in medicine, in material sciences, and in the nanotechnologies, including production of absorbers to remove undesired and toxic contaminants from factory effluents. Chemical and biochemical modifications of cellulose generate materials that can be used to produce ethanol (biofuel) by fermentation. 

Further work on these various processes may be needed to optimize catalyst life, separation, and recycle, as well as reaction rates. The preferred solvent, if any is required, would be ethanol instead of methanol, for the former is less toxic and can be produced readily from renewable sources by fermentatation (see Chap. 9). 

In 1997, at the United Nations Conference on Climate Change, the major industrial nations agreed to expand their research efforts to develop renewable sources of carbon-based fuels. For more than a decade, Brazil has been engaged in a program to replace gasoline with ethanol derived from the root crop manioc (cassava). 

Ethanol can be used for hydrogen production via steam reforming, with the advantage that it can be easily made from renewable sources [11]. A variety of catalysts was tested for this reaction, mainly Ni, Co, Cu and supported noble metals, including Rh, Pd and Pt [12,13]. 

Ethanol is being hailed as the fuel of the future. Interest in the production of fuel ethanol from renewable sources has increased significantly. For fuel ethanol production to become a practical reality, cheaper substrates and more efficient production processes are needed [1,2]. Biomass, which includes all plant and plant-derived material, forms a potential renewable source of sugars that can be fermented to produce fuel ethanol and a variety of other fuels and chemicals. In addition to the many benefits common to renewable energy, biomass is particularly attractive because it is currently the only renewable sustainable energy source for liquid transportation fuel. 

Although LAB have not been chosen yet to produce biofuels at industrial level, their high ethanol tolerance and ability to metabolize different sugars give the possibility of using renewable sources such as lignocellulosic feedstock or meso-2,3-butanediol make them interesting candidates. 

A great part of scientific literature is focused on carrying out this reaction using ethanol produced by no-renewable sources [125-130]. Concerning bioethanol steam reforming (BESR) reaction, only few studies are deal with both FBRs [131-133] and MRs use [134-136], as reported in Table 2.8. 

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