BIOMASS AND NATURAL-GAS AS CO-FEEDSTOCKS FOR PRODUCTION OF FUEL FOR FUEL-CELL VEHICLES

Prospects are examined for utilizing renewable energy crops as a sourc e of liquid fuel to mitigate greenhouse gas emissions from mobile sour ces and reduce dependence on imported petroleum. Fuel-cell vehicles wo uld provide a promising technology for coping with the environmental a nd economic effects of an expanding vehicle fleer and a decreasing pet roleum supply. Fueled with methanol or hydrogen derived From biomass, fuel cells can also effectively address the problem of CO2 emissions F rom that fleet. The extent to which this combination might affect petr oleum displacement depends on the amount of biomass that could be prod uced and the efficiency of its conversion to a fuel compatible with fu el cells. Reduction of net CO2 emissions by the best current bio-fuel technology will be limited by biomass supply. Biomass conversion effic iency, petroleum displacement and overall net CO2 emission reduction c an be improved, and the cost of fuel minimized, by use of natural gas as a co-feedstock. The extra hydrogen provided by natural gas allows t hese improvements by eliminating the partial shift of CO to CO2 that i s otherwise necessary; elimination of that step and additional in situ leveraging of fuel yield by conventional reforming reactions also red uce the production cost. A thermochemical process utilizing both bioma ss and natural gas as co-feedstocks is compared with other options for methanol production and CO2 mitigation using either biomass or natura l gas alone. Use of natural gas as co-feedstock makes possible the add itional environmental advantage of utilizing waste methane from landfi lls and waste-water treatment facilities, as well as the carbonaceous solid wastes and sludge from those facilities, for conversion to clean transportation fuel. Greenhouse pas emissions From these important mu nicipal sources can thus be concurrently I educed, together with landf ill disposal requirements. Published by Elsevier Science Ltd.