It was during this period that various other inventions took place like the use of gasoline along with alcohol that was derived from potatoes. Britain was the second country which came up with the concept of grain alcohol mixed with petrol. The wars frames were the periods when the various major technological changes took place but, during the period of peace, cheap oil from the gulf countries as well as the Middle East again eased off the pressure.
With the increased supply the geopolitical and economic interest in biofuel faded away. A serious fuel crisis again hit the various countries during the period of and , because of the geopolitical conflict. The constant shortage of fuel attracted the attention of the various academics and governments to the issues of energy crisis and the use of biofuels. The twentieth century came with the attention of the people towards the use of biofuels.
As a result, production of biodiesel grew rapidly. By , there were 25 biodiesel plants in the United States, and by , the National Biodiesel Board listed over manufacturers on its Web site. Worldwide, biodiesel production grew from about 1 billion liters in to 6 billion liters in Pahl, , p. Government policy has been very important to the development of the biodiesel industry in the United States.
The Energy Policy Act of , which was intended to reduce the need for imported petroleum, required government fleets to purchase alternatively fueled vehicles. More recently, the National Renewable Fuel Standard, released in , requires petroleum companies to buy alternative fuels in proportion to their sales of traditional petroleum fuels. This is expected to cause a similar boost in biodiesel sales.
The rapid growth of the biodiesel industry has fostered concern that farmers will be encouraged to grow more and more crops for fuel and that less and less land will be available for food. ILUC is the study of the indirect and unintended consequences in carbon emissions caused by production of a biofuel feedstock. For example, if more cropland is dedicated to producing biofuel feedstocks, perhaps forestland or wetlands somewhere else in the world might then be converted to cropland.
This land conversion causes carbon to be released into the atmosphere. Some scientists have suggested that because of indirect land use change, certain biofuels actually caused more carbon to be released into the atmosphere than the corresponding fossil fuel. Biodiesel, instead, could be seen as one part of a larger plan to reduce air pollution, carbon emissions, and dependence on fossil fuels.
Energy crops can also be an important source of income for farmers Van Gerpen et al. Scientists are currently researching ways to produce biodiesel using new feedstocks that are less limited by the availability of land. For example, some types of algae can produce oil. Nevertheless, although production of transportation fuels is possible out of syngas, it relies on the use of complex catalysts to induce the production of carbon-carbon bonds.
A typical example of such process is the Fisher-Tropsh process Jun et al. One of the simplest approaches for the industrial production of synfuels out of syngas is to produce methanol. Methanol can be produced from carbon monoxide and hydrogen directly under the action of a reducing catalyst. Methanol is an end product of its own but it cannot be used as additive for fuel at this point. Therefore, further transformation is required.
Relying on methanol as the starting material, many end products have been produced including alkanes via the methanol-to-gasoline MTG process, and ethanol via carbonylation processes Lavoie et al. Methanol is also investigated for the production of a new generation of fuels such as bioDME, produced through etherification of two methanol molecules. It has been reported as an additive to diesel Ribeiro et al. However, BioDME has specific properties that tend to limit its use in the transportation fuel market, specifically because of its low viscosity compared with diesel fuel causing excessive wear in fuel injection systems Ribeiro et al.
For example, gasification processes lead to the production of syngas and ultimately to transportation fuel e. Therefore, the process is highly dependent on the feedstock price because the conversion from biomass to syngas, the purification of syngas, and the catalytic synthesis of ethanol represent significant technological challenges. Therefore, the most homogeneous and expensive biomasses would not be good candidates for such technology.
Biomasses such as quasi-homogeneous or non-homogeneous would be more suitable Marie-Rose et al. An aspen forest in Coconino National Forest, Arizona. Many processes have been considered, including classical pulping processes Jin et al. Isolation of cellulose is a technological challenge because it has to produce the highest purity of cellulose to remove most inhibitors without consuming too much energy or too many chemicals.
Once purified, two approaches are generally used for saccharification of cellulose: either enzymatic Sun and Cheng, or by chemical hydrolysis using acids Chornet et al.
On the other hand, chemical processes rely on rather inexpensive chemicals e. Once isolated, the macromolecule i. Typical North American forest biomass weight e. The main advantage of hemicelluloses is that, due to their highly ramified structure, they can be hydrolyzed easily using water at high temperatures or a very diluted aqueous mixture of acids.
The key problem is that C5 sugars do not ferment with classical yeast strains and require genetically modified organisms to produce ethanol Matsushika et al. Furthermore, acids both acetic and formic may inhibit the fermentation process, requiring an additional operation for detoxification.
Another approach for valorization of C5 sugars could be via chemical pathways Fuente-Hernandez et al. Many researchers have been working on this specific approach in which C5 sugars like xylose are dehydrated to furfural 4A , which acts as a platform chemical and an intermediary from which drop-in fuels such as methyl tetrahydrofuran Figure 4B and ethyl levulinate Figure 4C could be produced.
The macromolecule is highly energetic and has been used for cogeneration Dickinson et al. Although they could be used as fuel or as a source of hydrogen in a biorefinery process, the aromatic monomers from lignin could also be a very abundant source of high value chemical compounds that could be used in the plastic industry, as well as adhesives.
In both cases, industrial-grade aromatics are actually obtained as side-products from petroleum. Consequently, the use of biomass to produce such monomers or green chemicals would lead to an interesting new market for bioadhesives and second-generation bioplastics.
Reported work on lignin has also shown that it is possible to convert part of it into transportation fuels such as jet fuel Shabtai et al. Chemical structures of furfural A , methyl tetrahydrofuran B , and ethyl levulinate C. The most accepted definition for third-generation biofuels is fuels that would be produced from algal biomass, which has a very distinctive growth yield as compared with classical lignocellulosic biomass Brennana and Owendea, Production of biofuels from algae usually relies on the lipid content of the microorganisms.
There are many challenges associated with algal biomass, some geographical and some technical. The high water content is also a problem when lipids have to be extracted from the algal biomass, which requires dewatering, via either centrifugation or filtration before extracting lipids.
Lipids obtained from algae can be processed via transesterification by the previously described biodiesel process or can be submitted to hydrogenolysis to produce kerosene grade alkane suitable for use as drop-in aviation fuels Tran et al.
A researcher from Sandia National Laboratories views an algae sample as part of a project to cultivate green algae as a new biofuel supply. First-generation biofuels are well implemented around the world, although they may come with certain restrictions such as energy consumption and utilization of arable lands, as well as the fuel versus food debate.
Nevertheless, they remain a sure and economically viable approach for sustainability and reduction of fossil fuel consumption. Ethanol from corn is limited by a similar paradox with the increasing value of food on the world's market. The same reality applies for the biodiesel market, which is limited by the price of vegetable oils. In all cases, feedstock is getting increasingly expensive, leading to a growing interest toward second-generation biofuels. The latter is produced from a generally less expensive biomass such as forest, agricultural, animal, or municipal wastes.
In the middle spectrum, the most abundant product is pyrolytic oil, and at high temperatures, syngas. In case of pyrolytic oil and syngas, they could be considered as intermediaries, leading to the downstream production of biofuels e. The process requires pre-treatment for isolation of cellulose from the other macromolecules in the biomass. Third-generation biofuels are mostly related to algae. Therefore the major difference between the second and third-generations is the feedstock.
Algae are known to produce biomass faster and on reduced land surface as compared with lignocellulosic biomass. Nevertheless, production of algal biomass presents technical challenges such as lipid extraction and dewatering, as well as geographical challenges in areas like Canada where temperature are below freezing for a large part of the year.
The future of biofuels may not rely solely on one generation, but may be a combination of the three generations to cope with increased worldwide demand as a result of depletion in the world's oil resources. His current work is in three of the research group's main areas of research: production of syngas, depolymerization of cellulose, and catalytic lignin depolymerization.
During his Ph. A and a Ph. The chair has a strong relation with the industry, having developed an industrial-academic cooperation model where students interact on both the academic and industrial levels.
His team is now composed of more than 25 students and researchers, and their work is oriented for fast scale up. His field of expertise includes gasification, pyrolysis, torrefaction, fractionation, reforming, and intermediates upgrading.
He has published more than 20 peer-reviewed papers in the field and was invited as guest speaker to more than 10 international conferences.
He is the author of seven patents. Beauchet R. Conversion of lignin to aromatic-based chemicals L-chems and biofuels L-fuels. Google Scholar.
Bonhorst C. Esters of naturally occurring fatty acids—Physical properties of methyl, propyl, and isopropyl esters of C6 to C18 saturated fatty acids. Brennana L. Biofuels from microalgae—A review of technologies for production, processing, and extractions of biofuels and co-products. Renewable Sustainable Energy Rev. Brosse N. Chen C.
Cultivation, photobioreactor design, and harvesting of microalgae for biodiesel production: A critical review. Chornet M.
0コメント