First Data on Underground Coal Gasification at the Experimental Gas Generator of the Angren Podzemgaz Station

摘要

The following conclusions were developed from this field test: The low gas permeability of the coal seam and the tendency of the coal toward self-ignition restrict the use of percolation linkage of boreholes at the Angren Podzemgaz Station. The method of hydraulic fracture of the coal seam at Angren can effect an increase in rate and improvement of the flow indices of the linking process. When hydraulic fracture was carried out wih a water supply rate of 2 m exp 3 /min, channels were formed linkage of which was carried out mainly with medium-pressure air - at up to 7.5 at - at a rate of over 1.8 running meters/day. Upon partial hydraulic fracture, when for various reasons the process did not bring about a sharp decrease in the hydraulic resistance of the section, water supply to the coal seam led to an increase in steam permeability; fire linkage of the boreholes to the fire face then proceeded at a rate close to 2 m/day, with air consumption of 5,400-13,300 Nm exp 3 per running meter of channel under a high-pressure and later a medium-pressure air flow. Gasification of the coal seam in the channels formed by using hydraulic fracture of the seam proceeded stably. Gasification was carried out at limited air flow rates - up to 2500 Nm exp 3 /hr - with production of gas whose weighted mean combustion heat was 913 kcal/Nm exp 3 over the entire period, and 1070 kcal/Nm exp 3 over the period when the air flow was supplied at a rate of over 1500 Nm exp 3 /hr. (ERA citation 05:035884)