Upgrading of low rank coal as coal water slurry and its utilization

In this paper, a new brown coal utilization process, combining the techniques of coal/water slurry (CWS) production and CWS in-line vaporization, was proposed. In the process, brown coal was converted to CWS with high-pressure kneader under mechanical shear stress and moderate heating. Water in the CWS was vaporized with a special designed pre-heater, termed an in-line vaporizer, processing about 2.0 t/day (dry coal basis). Indonesian brown coal containing 22% moisture and Australian brown coal containing 59% moisture were successfully converted to CWS. The Australian brown coal CWS was pre-heated with the in-line vaporizer. The CWS was converted to a coal/steam mixture without plugging of the feed tube and directly burned in a combustion furnace.