Laboratory-Scale Studies on Humidified O2-Fed High-Ash Coal-Based Underground Coal Gasification

Abstract

With the depletion of coal reserves all over the world, efforts are being made worldwide to utilize those deep underground coal seams, which are difficult to mine or are not feasible economically. Underground coal gasification (UCG) is a promising technology to achieve that objective and also to reduce the atmospheric pollution that is casued by surface gasification of the mined coal. Based on the previous research performed in this field, it is a well-known fact that the optimum quantity of water influx into coal seam can increase the hydrogen content of the product gas. In our earlier study, a novel method of utilizing humidified oxygen as the gasification agent was conducted for low ash coal gasification. The experimental results had shown the production of substantial quantity of hydrogen in the product gas. In the present study, the laboratory-scale experiments are extended to high-ash Indian coals with increases in the absolute humidity of the feed oxygen by preheating the water (humidifying medium)...