Biodiesel utilization

Currently, 58 biodiesel plants operate in the United States with a total capacity to produce 1.3 million tons of fuel and an average capacity per plant of 22 thousand metric tons (Fig. 5.33). An additional 53 plants are planned for construction with a total capacity of 2.4 million tons and an average size of 45 thousand tons. The industry is young and highly fragmented as 80% of the production is produced by 33% of the firms (Fig. 5.34). Soybeans would feed about 47% of the planned biodiesel production. The 940 thousand metric tons of additional oil demand would still only equal 10% of the 2005 U.S. oil supply, up from the current 3%. So the direct price effects from U.S. biodiesel expansion would be moderate. Most of the price effects on food oils will come from much more rapid expansion of biodiesel utilization in Europe and Asia. 

It is the last two problems, particularly in urban areas, that are causing most public concern. Most recent research into biodiesel has focused on vegetable oils such as soybean, sunflower, palm and rapeseed. Although animal fats have been considered, their availability in the quantities required have precluded serious utilization. 

Apart from a few reports" on solid acid catalyzed esterification of model compounds, to our knowledge utilization of solid catalysts for biodiesel production from low quality real feedstocks have been explored only recently. 12-Tungstophosphoric acid (TPA) impregnated on hydrous zirconia was evaluated as a solid acid catalyst for biodiesel production from canola oil containing up to 20 wt % free fatty acids and was found to give ester yield of 90% at 200°C. Propylsulfonic acid-functionalized mesoporous silica catalyst for esterification of FFA in flotation beef tallow showed a superior initial catalytic activity (90% yield) relative to a... 

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... 

Biodiesel from oilseed rape straw utilized Bioethanol from wheat straw utilized... 

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. 

One approach that could enable the production of cheaper biodiesel is to utilize low-value vegetable oils that contain a high content of FFA. This is particularly attractive as such materials can be obtained from either waste or the cultivation of alternative crops, something that would increase the biodiversity from which biofuels... 

The Biodiesel Stability (BIOSTAB) project, supported by the European Commission, was initiated in 2001 to establish clear criteria and analytical methods for the monitoring biodiesel fuel stability (Various, 2003 Prankl, 2002). The resulting unified method, EN 14112 (Anon., 2003c) established a means for measuring oxidative stability utilizing the Rancimat or oxidation stability instruments. This test method was essentially developed from standards employed in the fats and oils industry to measure isothermally the induction period for oxidation of fatty derivatives. At present, both biodiesel fuel standards ASTM D 6751 (Anon., 2007a) and EN 14214 (Anon., 2003b) include an oxidative stability specification based on measurement by method EN 14112. 

Ban, K., Kaieda, M., Matsumoto, T., Kondo, A., and Fukuda, H. 2001. Whole cell biocatalyst for biodiesel fuel production utilizing Rhizopus oryzae cells immobilized within biomass support particles. Biochem. Eng. J.,8, 3 43. 

---