Innovative process for concentration of fine particle coal slurries. Final technical report, September 1, 1995--August 31, 1996

Williams Technologies, Inc. And Clarke Rajchel Engineering are developing a technology (patent pending) to produce high quality coal water slurries from preparation plant fine coal streams. The WTI/CRE technology uses the novel implementation of high-shear cross-flow separation which replaces and enhances conventional thickening processes by surpassing normally achievable solids loadings. Dilute ultra-fine (minus 100 mesh) solids slurries can be concentrated to greater than 60 weight percent and remixed, as required, with de-watered coarser fractions to produce pumpable, heavily loaded coal slurries. The permeate (filtrate) resulting from this process has been demonstrated to be crystal clear and totally free of suspended solids. The primary objective of this project was to demonstrate the WTI/CRE coal slurry production process technology at the pilot scale. The technology can enable Illinois coal producers and users to realize significant cost and environmental benefits both by eliminating fine coal waste disposal problems and producing an IGCC fuel to produce power which meets all foreseeable clean air standards. Testing was also directed at concentrating mine tailings material to produce a tailings paste which can be mine-back- filled, eliminating the need for tailings ponds. During the grant period, a laboratory-scale test apparatus (up to 3 GPM feed rate) was assembled and operated to demonstrate process performance over a range of feed temperatures and pressures. A dilute coal/water slurry from Consol, Inc.`s Rend Lake Preparation Plant was concentrated with the process to a maximum recorded solids loading of 61.9% solids by weight. Analytical results from the concentrate were evaluated by Destec Energy for suitability as an IGCC fuel.