Application of Ultrasonic Techniques to Chemical Coal Cleaning Processes. Final Report, April 15, 1980-August 15, 1981

摘要

Ultrasonic activation was applied to several coal cleaning processes, including chlorinolysis, oxydesulfurization, and sodium hypochlorite leaching, in small-scale batch treatment processing of Illinois No. 6, Lower Kittanning, and Western Kentucky No. 11 coals. In all cases, ultrasonic energy application demonstrated effects that would translate in production to processing efficiencies and/or capital equipment savings. Specifically, in the chlorinolysis reaction, pyritic sulfur was removed 23 times faster with ultrasonics than without it. (Organic sulfur could not be removed from the coal examined with or without ultrasonics in the chlorinolysis process). In sodium hypochlorite leaching, the total sulfur extraction rate was 3 times faster with ultrasonics. Two separate benefits were seen with oxydesulfurization: ultrasonics doubled the reaction rate and at slightly accelerated rates allowed a pressure reduction from 960 to 500 psi, which would be a significant cost efficiency in production. With these results, it was recommended that ultrasonic processing be investigated with a process involving interactions similarly amenable to ultrasonic enhancement, i.e., molten salt leaching, which is reported to have the potential not only for more extensive sulfur extraction than the other experimental processes, but for ash removal as well.