RHEOLOGY OF COAL WASTE COPROCESSING MIXTURES

The economical recycling of waste materials to produce liquid fuel fee dstocks is being investigated. Particular emphasis at the Pittsburgh E nergy Technology Center (PETC) has been given to coal/waste coprocessi ng. Coal/waste coprocessing represents the conversion, into fuels and higher value products, of coal with a combination of any or all of the following: plastics, rubber, heavy oil, waste oil and paper. This stu dy focuses on the rheology of various mixtures of coal, plastics, rubb er and oil in order to facilitate their pumping in coal/waste coproces sing continuous units. The rheological properties of these mixtures de termine their pumpability and the feed system requirements for the slu rries. The viscosities of coal/waste mixtures were measured at various temperatures and shear rates. It was noted that these mixtures had no n-Newtonian flow properties, hence their viscosities were a strong fun ction of shear rate. The relative amounts of coal, plastics (and plast ics type), rubber and oil were varied in order to evaluate their effec t on apparent viscosity. A bench-scale continuous unit was used to eva luate the pumpability of slurries that represent mixtures that may be used in coal/waste coprocessing. (C) 1997 Elsevier Science S.A.