Robert H. Borgwardt

Sintering of nascent calcium oxide

Abstract The sintering rate of calcium oxide in a nitrogen atmosphere was measured at temperatures from 700 to 1100°C. CaO prepared from ultrapure CaCO 3 was compared with impure CaO derived from limestone and calcium hydroxide. CaCO 3 derivatives yielded an initial surface area of 104m 2 /g and the hydroxides, 76.7m 2 /g. The rate of surface reduction was independent of particle size between 2 and 20 μm, but strongly dependent on temperature and impurities. Impurities increased the rate of sintering at a given temperature and reduced the activation energy. The model of German and Munir (J. Am. Ceram. Soc., 59, 379-383, 1976) correlates the kinetics of surface reduction and identifies lattice diffusion as the mechanism of solid transport. Porosity declined logarithmically with time during the intermediate stage of sintering.

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 source of liquid fuel to mitigate greenhouse gas emissions from mobile sources and reduce dependence on imported petroleum. Fuel-cell vehicles would provide a promising technology for coping with the environmental and economic effects of an expanding vehicle fleet and a decreasing petroleum supply. Fueled with methanol or hydrogen derived from biomass, fuel cells can also effectively address the problem of CO2 emissions from that fleet. The extent to which this combination might affect petroleum displacement depends on the amount of biomass that could be produced and the efficiency of its conversion to a fuel compatible with fuel cells. Reduction of net CO2 emissions by the best current bio-fuel technology will be limited by biomass supply. Biomass conversion efficiency, petroleum displacement and overall net CO2 emission reduction can 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 these improvements by eliminating the partial shift of CO to CO2 that is otherwise necessary; elimination of that step and additional in situ leveraging of fuel yield by conventional reforming reactions also reduce the production cost. A thermochemical process utilizing both biomass and natural gas as co-feedstocks is compared with other options for methanol production and CO2 mitigation using either biomass or natural gas alone. Use of natural gas as co-feedstock makes possible the additional environmental advantage of utilizing waste methane from landfills and waste-water treatment facilities, as well as the carbonaceous solid wastes and sludge from those facilities, for conversion to clean transportation fuel. Greenhouse gas emissions from these important municipal sources can thus be concurrently reduced, together with landfill disposal requirements.

PLATINUM, FUEL CELLS, AND FUTURE US ROAD TRANSPORT

Abstract The rate at which fuel cell vehicles (FCVs) might displace the conventional fleet is examined under constraints imposed by the limited availability of platinum. It concludes that a transition period as short as 31 years is not feasible. Under the most favorable circumstances, a complete transition of the US fleet to this new technology would require about 66 years and 10,800 net tonnes of platinum. Platinum demand for the US auto industry alone would amount to 48% of world production during much of that transition period. The effect of that demand on the price of platinum would add to the problem of reducing vehicle cost to a competitive range. If US platinum consumption were to remain at its current level of 16% of annual world production, fleet conversion would require 146 years. These results imply that, without alternative catalysts, fuel cells alone cannot adequately address the issues facing the current system of road transport.

THE COPROCESSING OF FOSSIL FUELS AND BIOMASS FOR CO2 EMISSION REDUCTION IN THE TRANSPORTATION SECTOR.

Research is underway to evaluate the Hydrocarb process for conversion of carbonaceous raw material to clean carbon and methanol products. These products are valuable in the market either as fuel or as chemical commodities. As fuel, methanol and carbon can be used economically, either independently or in slurry form, in efficient heat energies (turbines and internal combustion engines) for both mobile and stationary single and combined cycle power plants. When considering CO{sub 2} emission control in the utilization of fossil fuels, the copressing of those fossil fuels with biomass (which may include, wood, municipal solid waste and sewage sludge) is a viable mitigation approach. By coprocessing both types of feedstock to produce methanol and carbon while sequestering all or part of the carbon, a significant net CO{sub 2} reduction is achieved if the methanol is substituted for petroleum fuels in the transportation sector. The Hydrocarb process has the potential, if the R&D objectives are achieved, to produce alternative transportation fuel from indigenous resources at lower cost than any other biomass conversion process. These comparisons suggest the resulting fuel can significantly displace gasoline at a competitive price while mitigating CO{sub 2} emissions and reducing ozone and other toxics in urban atmospheres.

A technology for reduction of CO2 emissions from the transportation sector

Abstract By sequestering byproduct carbon and replacing petroleum fuels with biomass-derived methanol, the Hydrocarb process can nullify the net effect of CO2 emissions from motor vehicles. This paper gives a preliminary assessment of the process which indicates that substantially more fuel energy could be produced--and at lower cost--than other current options for mitigating CO2 from mobile sources. The incremental cost of eliminating net CO2 emissions is estimated at

Calcium oxide sintering in atmospheres containing water and carbon dioxide

0.05 per gallon (3.78 liters) of gasoline displaced by methanol. About 80 percent reduction should be achievable at no incremental cost.