In early studies addressing national energy/environmental (EE) problems we concluded that co-utilization of domestic fuels can significantly reduce national reliance on imported fuels, mitigate NOx, SOx, CO2 and other undesirable emissions and provide valuable waste disposal services. Co-firing of coal and biomass for steam turbine power generation is a near-term co-utilization approach that can make use of existing facilities with relatively minor modifications. However, co-gasification by providing fuel for more efficient combustion turbines and fuel cells and co-liquification to produce transportation fuels have greater long-term EE potential. The development of optimum thermo-chemical co-conversion systems can be fostered by developing a common systematics for the pyrolysis of biomass and coal. Towards this goal we have used the large data bases from ASTM standard ultimate and proximate analyses for all fuels along natures coalification path from biomass to peat, lignite, bituminous and anthracite coal. With this composite data we find systematics in the weight percentages of carbon, hydrogen, total volatiles, fixed carbon and feedstock HHVs vs the weight percentage of oxygen. To meet the need for knowledge of the volatile constituents we have used sparsely available slow pyrolysis data in the literature and our own data to further develop a plausible semi-empirical model (SEM) that relates feedstock and product compositions. We here extend these analytic correlations to lower temperatures with the help of CCTL measurements of yields from the pyrolysis of rice hulls. We have recently applied this SEM to exam the systematic yields of a short list (SL) of products (five gases and five liquids) vs [O], the weight percentage of oxygen in the feedstock. Here anchored to the rice hull data we use our analytical relationships to estimate the yields of a long list (LL) of products including many organic compounds that are known to be slow pyrolysis products of coals and biomass. These relations are put forth as a heuristic challenge to ourselves and to specialists in biomass and coal pyrolysis to obtain more and better data and to seek improved engineering formulas that are needed to advanced co-utilization technology. Then energy debtor nations could utilize all of their available domestic fuels, including opportunity fuels, to mitigate their national EE problems. These preliminary results point to a path towards the development of a co-utilization science and technology for optimizing feedstock blends in many co-firing, co-gasifying or co-liquifying applications.

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