The transportation sector in the US is the only element that is almost totally dependent on petroleum for its energy supply. With more than half of all petroleum imported, transportation, which is vital to the US economy, is very vulnerable to economic and strategic disruptions. With about twothirds of all oil being used for transportation.
it also contributes substantially to the large trade deficit for petroleum imports. Transportation fuels contribute about half the urban air pollution and a third of the carbon dioxide accumulation that could result in global climate change. Because lignocellulosic biomass sources such as agricultural and forestry residues, municipal solid waste, and woody and herbaceous crops could be abundant, production of fuels from biomass could address all these problems on a large scale. Biomass can be gasified by thermal processes to produce a mixture of carbon monoxide and hydrogen that can be catalytically combined to form methanol. Alternatively, the cellulose and hemicellulose in biomass can be broken down to their component sugars for fermentation to ethanol. Although ethanol and methanol are currently most favored for use as transportation fuels, other acohols could also be formed thermally or biologically from biomass. Ethanol and methanol can be used directly as neat or pure fuels. Ethanol is also directly blended with gasoline to displace gasoline use, increase the octane of the blended fuel, and provide oxygen that insures more complete combustion and reduces the contribution to urban air pollution. 97102918 Calculation of higher heating values of biomass fuels Demirbas, A. Fuel, 1997, 76, (S), 431-434. Calorific values (higher heating values, HHV) of 16 biomass samples obtained from different Turkish sources were determined experimentally and calculated from both ultimate and proximate analyses.