BIOFUELS
Two problems roused the world’s concern in recent years. One is energy crisis caused by the squandering of petroleum fuel. Second problem is environmental problems such as greenhouse effect, global warming, etc. To deal with such problems, renewable sources, utilization technology and bioenergy production technology have been developed. Bioethanol as one of the biofuel can be blended in different proportions in automobiles with gasoline. Biobutanol is also a new biofuel (Liu, Wang, & Zhang, 2009). Production through ABE fermentation of acetone, butanol and ethanol was discovered over 100 years ago. In 1861, Pasteur discovered that anaerobic bacteria could produce butanol. In 1905, Schardinger discovered that anaerobic bacteria could…show more content… Primary biofuels are procured from natural and unprocessed raw materials; the organic material is exploited in its natural and non- modified chemical form like fuelwood, wood chips and pellets, etc. Primary fuels are directly combusted to provide power for various processes like cooking, heating, or electricity production needs in small and large-scale industrial operations. Whereas, secondary biofuels are retrieved from processed biomass, and have immense utilization in transportation and diverse industrial mechanisms.
Secondary biofuels can be produced in the form of solids (e.g. charcoal, fuelwood, wood pellets), or liquids (e.g. ethanol, biodiesel, butanol, pyrolysis oils and bio-oil), or gases (e.g. biogas, synthesis gas, methane and hydrogen) (Nigam & Singh, 2011). The secondary biofuels can be segregated into first, second and third-generation biofuels based on the substrate availability, technology maturity and GHG gas emission balance. (Bharathidasan et al. 2011). Research has provided more progressive and productive conversion technologies for the extraction of biofuels in solid, liquid and gaseous forms from ingredients such as wood crops and waste material. (Nigam & Singh,…show more content… The products are a mixture of n-butyraldehyde and isobutyraldehyde which is then hydrogenated to n-butanol and isobutyl alcohols. (Niemisto et al., 2013)
The reaction processes at 10∼20MPa and 130∼160°C, when cobalt is used as the catalyst. The products ratio of n-butyraldehyde and isobutyraldehyde is 3. The reaction processes at 0.7-3MPa and 80-120°C, when rhodium is used as the catalyst. The products ratio of n-butyraldehyde and isobutyraldehyde of 8-16 can be achieved. The catalysts of nickel or copper in gaseous phase or nickel in liquid phase are used for hydrogenation.
Second process is aldol condensation, in this reaction; two molecules of acetic aldehyde condense by dehydration. The product crotonaldehyde is then transformed into n-butanol by hydrogenation at 180°C and 0.2MPa. The reaction is as follows:
CH3CH=CHCHO+2H2