APPLICATIONS OF CARBONIZED SEWAGE SLUDGE AS A SLURRY FUEL

摘要

This paper will present the results of an investigation of the applicability of a carbonized sewage sludge slurry as a boiler fuel. The process used was developed by EnerTech Environmental, Inc. Under high temperatures and pressure, sewage sludge is converted to a carbonized particulate slurry. The acceptability of this slurry either as direct injection or a component of a coal slurry as a boiler fuel was examined in terms of handling properties and optimum composition. Several process conditions were studied including two different temperatures and pressures for the production of the carbonized slurry. Rheological investigations were conducted to determine the viscosity under a variety of conditions. Predictions were made on the maximum allowable solids concentration carbonized slurry (CMSS) and mixtures of CMSS/coal slurries. In addition, a series of chemical dispersants were studied to examine the effect on increasing the allowable solids content. Both for CMSS and CMSS/coal slurries, it was possible to determine and optimum prescription to obtain solids contents in the 40-50% range. This presents and acceptable result for using this fuel, especially in light of the large cost advantage due to sewage tipping fees. The sources used for the sewage were obtained from several municipalities in the Kearny, NJ area. This is the location of an EnerTech production plant, 60 dry tons/day which will be in production early in 2002. This project also involved and assessment of the potential users of the product of this plant. Using the DOE database, a list of power plants was evaluated and a general scenario for demonstration and utilization analyzed. The overall result was this carbonized sewage sludge presents a viable fuel for utilities when used in conjunction with coal. Since the quantity of the fuel used is only a small percentage of the total fuel used, it was estimated that environmental impacts would be minimal.