According to information accessed via the link, this article is adapted from a technical paper presented at the 1998 International Gas Turbine & Aeroengine Congress & Exhibition in Stockholm, Sweden.
We presume you to know by now the significance of the word "syngas" in the title.
Some excerpts:
"Commercial Viability
Rheinbraun concluded that co-gasification of sewage sludge or loaded coke with dried brown coal offered significant potential for disposing of these wastes without impairing plant efficiency and emissions. The commercial viability was demonstrated by an assessment study that included major aspects such as feed rate, total investment, and methanol price in order to establish the criteria for the use of sewage sludge in the high-temperature Winkler gasification process.
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A separate part of the program, coal-biomass environmental studies, undertaken by CRE Group and Imperial College of the United Kingdom, and TPS Termiska Processer AB and Kungl Tekniska Hogskolan of Sweden, concentrated on the use of laboratory-scale experimental techniques to study the influences of several fuels on gasification behavior. The studies found that when coal and biomass or wastes were co-gasified, the overall level of tars generated was lower than for coal alone; the concentration of hydrocarbons in the range of C1 to C7 was increased, and product gas yields increased and char levels decreased, with co-gasification chars being significantly more reactive. In addition, the heightened char reactivity resulted in increased conversion of NO and NH3 to N2 ..."
As we've documented from other sources, in separate dispatches, the addition of biomass,and, in this case, sewage sludge, to coal for gasification improved the yield of syngas (i.e., "gas", above), and the presumed subsequent productivity of liquid fuel.
Moreover, the reactive by-products of the combined coal/biomass/sewer sludge gasification reduced the emission of undesirable Nitrogen Oxide, converting it into harmless Nitrogen gas and an ammonia radical that would be useful for fertilizer co-production.