Biofuels bioethanol

Kim, S., Dale, B.E. 2005. Life cycle assessment of various cropping systems utilized for produe-ing biofuels bioethanol and biodiesel. Biomass Bioenergy 29 426 39. 

The use of lignocellulosic materials (e.g., agricultural wastes) in the production of second-generation biofuels (bioethanol, biobutanol) or the manufacture of new cellulose-derived and Ugnin-derived value-added products. 

Carbon footprint of transport biofuels (biodiesel, bioethanol, biomethane)... 

BP has investments in an ethanol plant with DuPont and Associated British Foods. It is also investing in cellulosic ethanol research and developing jatropha as a biodiesel feedstock. BP and DuPont are planning a biobutanol demonstration plant and BP would like to eventually convert their ethanol plant to biobutanol production. BP has a 400 million investment with Associated British Foods and DuPont to build a bioethanol plant in the U.K. that may be converted to biobutanol. It has spent 500 million over 10 years at the Energy Biosciences Institute in California to research future biofuels and 9.4 million over 10 years to fund the Energy and Resources Institute (TERI) in India to study the production of biodiesel from Jatropha curcas. It also has a 160 million joint venture with D1 Oils to develop the planting of Jatropha curcas. 

Bioethanol is the largest biofuel today and is used in low 5%—10% blends with gasoline (E5, E10), but also as E85 in flexible-fuel vehicles. Conventional production is a well known process, based on the enzymatic conversion of starchy biomass (cereals) into sugars, and fermentation of 6-carbon sugars with final distillation of ethanol to fuel grade. 

In the European Union, ethanol is consumed in Spain, France, Sweden and Germany, especially after conversion into ETBE (ethyl tert-butyl ether), except in Sweden, but its use is increasing in all the other countries. New uses of bioethanol, e.g., in ethanol-direct fuel cells or as raw material for other chemicals, will further expand bioethanol use and production. Table 9.1 summarizes bioethanol production in different countries by 2004 [1], Owing to political decisions (EU directive setting at 5.75% the proportion of biofuels in fuels) and incentive taxation... 

Figure 9.1 reports the prospective average biofuel yield from different crops in EU-15 over 2005-2010 (GJ ha-1) [3]. Bioethanol yield in EU-15 normally is higher than the biodiesel yield, e.g., a smaller land area will be needed to produce... 

Notably, however, any comparison of biodiesel vs. bioethanol should be done with great caution, because analysis of an industry such as that related to biofuels is a very complex task and all conclusions are country dependent. It may be interesting, however, to compare the energy balance and environmental impact in producing biodiesel from oilseed rape and bioethanol from wheat crops [4], Table 9.3 reports this comparison. The energy balance for bioethanol is more positive than for biodiesel, in particular when straw is utilized, mainly due to the higher yield... 

This chapter, after an introduction on the production methods for bioethanol and its use as biofuel, discusses the catalytic upgrading and valorization of bioethanol. 

Bioethanol is already a produced world-wide in large amounts (over 50 million tons), mainly by fermentation of sugars and crops. Its market is expected to grow largely in the next 5-10 years, mainly due to its use as biofuel, because of various socio-economic and strategic motivations, as discussed in this chapter and elsewhere in this book. 

Combinations of 1st and 2 nd generation conversion routes and technological coupling of biofuel and electricity conversion ( hybrids ) are potential options in the near future. For example, the process efficiency for a combined cycle (CC) is typically around 50% and could be improved to about 58% using a combination of BtL and CC or to around 70% using bioethanol produced from lignocellulose combined with BtL and CC [2],... 

The valorization of by-products in biomass conversion is a key factor for introducing a biomass based energy and chemistry. There is the need to develop new (catalytic) solutions for the utilization of plant and biomass fractions that are residual after the production of bioethanol and other biofuels or production chains. Valorization, retreatment or disposal of co-products and wastes from a biorefinery is also an important consideration in the overall bioreftnery system, because, for example, the production of waste water will be much larger than in oil-based refineries. A typical oil-based refinery treats about 25 000 t d-1 and produces about 15 000 t d 1 of waste water. The relative amount of waste water may increase by a factor 10 or more, depending on the type of feed and production, in a biorefinery. Evidently, new solutions are needed, including improved catalytic methods to eliminate some of the toxic chemicals present in the waste water (e.g., phenols). 

Biofuels such as bioethanol and biodiesel originate from cereal crops such as plant oils, and sugar beets. Today the production cost of bioethanol cereal crops is still too high, which is the major reason why bioethanol has not made its breakthrough as a fuel source yet. When producing bioethanol from maize or sugar cane the raw material constitutes about 40-70% of the production cost. 

The term energy crop can be used both for biomass crops that simply provide high output of biomass per hectare for low inputs, and for those that provide specific products that can be converted into other biofuels such as sugar or starch for bioethanol by fermentation, or into vegetable oil for biodiesel by transesterificatiou... 

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