Task 3.16 -- Low-cost coal-water fuel for entrained-flow gasification. Semi-annual report, July 1--December 31, 1995

Continued interest in gasification technologies has led to the need for more technological advances in the area of fuel cleanup and fuel feed systems, which invariably affect the other components comprised by gasification systems. Some entrained-flow gasifiers require the fuel to be a slurry form or a coal-water fuel (CWF). Recent technological advances at the Energy and Environmental Research Center (EERC) have led to potential means for improving efficiency and air toxics control for gasifiers that utilize CWF. Highly reactive low-rank coals present an attractive CWF gasification feedstock. Hydrothermally treating low-rank coals allows a CWF to be formulated that has an elevated solids content, which reduces the amount of water fed to the gasifier, thereby decreasing the amount of oxygen needed to gasify the coal. Preliminary measurements show that the process would increase the solids content from 53 to 63 wt%, giving a 20% improvement in energy density. The specific objective of this research project is to assess the potential process efficiency and pollution control benefits that may result from applying the hydrothermal, or hot-water-drying (HWD), process to low-rank coals as related to entrained-flow gasification systems. Project emphasis is on identifying more efficient coal dewatering and CWF formulation methods prior to gasification