Fuel substitutes, fossil

X 10 Btu/short ton), the solar energy trapped in 17.9 x 10 t of biomass, or about 8 x 10 t of biomass carbon, would be equivalent to the world s fossil fuel consumption in 1990 of 286 x 10 J. It is estimated that 77 x 10 t of carbon, or 171 x 10 t of biomass equivalent, most of it wild and not controlled, is fixed on the earth each year. Biomass should therefore be considered as a raw material for conversion to large suppHes of renewable substitute fossil fuels. Under controlled conditions dedicated biomass crops could be grown specifically for energy appHcations. 

This final section deals with the dehalogenation of pyrolysis oils from electronic scrap. In terms of using those materials for feedstock recycling, synthesis gas production or fossil fuel substitution, dehalogenation is strongly required. For feedstock recycling a 10 ppm... 

This approach to the preliminary assessment of the potential of biomass energy presumes that suitable conversion processes are available for conversion of biomass to SNG. Other processes could be used to manufacture other synfuels such as synthesis gas, alcohols, esters, and hydrocarbons. The direct route, alluded to in Fig. 2.1 as natural production of hydrocarbons, can possibly bypass the harvesting-conversion routes. As already mentioned, some biomass species produce hydrocarbons as metabolic products. Natural rubber, glycerides, and terpenes from selected biomass species, for example, as well as other reduced compounds could be extracted and refined to yield conventional or substitute fossil fuels. 

Bioethanol is bio-fuel substitute of gasoline, i.e., it is ethanol obtained from biomass, not from fossil fuels, and is used as a gasoline blend. 

The pattern of consumption of conventional energy in the United States shows that only 20 per cent of the heat is converted to electrical energy and the balance to industrial heat, individual home space heating, and transportation. Product manufacturing.by industry accounts for about 30 per cent of this nonelectrical energy consumption. The substitution of nuclear fuel for fossil fuel in this latter area is now prevalent. 

As seen in Table 5.1, the mechanical properties of polymer composites compare very well with those of other materials, and further substitution for at least some of the metal in an automobile is feasible. Functionally equivalent plastic components that can replace metal counterparts weigh 50-75% less. Typically, a 10% reduction in vehicle weight is estimated to reduce its fuel consumption by about 5-8%. Therefore, this weight advantage translates into very significant improved fuel efficiency, fossil fuel conservation, and avoided carbon emissions, given the size of the world fleet of vehicles. 

For a biofuel to be competitive with fossil fuels, economics are the ruling factor that determines their viability. It has been estimated that to be considered as a route to a fossil fuel substitute, a microbial fermentation process needs to produce biofuel at a concentration of at least 100 g/L, with productivity greater... 

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