Underground coal gasification - with seam divided into panels with separate extraction of gasification gases and carbonization gases

摘要

A system for the underground gasification of a coal seam in situ sustains the combustion by a gasification medium, rich in oxygen, which is piped below ground from the surface. The gasification gases produced in the gasification areas are kept separate from the carbonisation gases produced in the carbonisation gases produced in the carbonisation areas by the effect of the hot gasification gases. They are either exhausted through separate boreholes and shafts to the surface or they are mixed in a certain ratio, controlled automatically by the pressure ratios in the exhaust systems. This system can be so controlled that a predetermined constant calorific value of adequate magnitude can be maintained in the exhausted gas. No complicated apparatus is required.