Heat transfer in lignite block at high temperature

Heat transfer in coal seam is very important for the underground coal gasification process. A model test for studying the heart transfer rate and temperature variation rate in lignite block, isotherm distribution and temperature gradient around the hot coal wall was carried out. The test results show that the heat transfer rate and temperature variation rate in the coal seam are very small, while the temperature gradient is very large, all these phenomena is closely related with the permeability of the coal seam. Which suggest that we should consider the performance of heat transfer in the coal seam to control the velocity and direction of the flame transfer in the coal seam during the underground coal gasification, which is significant for obtaining high quality syngas steadily.