Disclosed are extraction device and method utilizing a
microwave coal heating layer. The extraction device mainly comprises an extraction and drainage
pipe (1), a
helical antenna (7), a front-loaded cover (6), a cable (8), a
microwave generator (9), a controller (10), a cooling device (11), a gas
exhaust pipe (12) and the like. The problems of low extraction rate and extraction speed of existing
extraction methods are solved. The extraction method is characterized by including: firstly drilling a hole at an appointed position of an extraction
coal layer, paving an anchorage net on the surface of the extraction
coal layer and drilling a
drill rod to reinforce the coal layer; placing the extraction and drainage
pipe with the
helical antenna into the drilled hole by the distance 0.6-1.0m away from the coal layer, sealing the hole by high-temperature-resistant
cement grouting, and starting the
microwave generator to heat the extraction coal layer to the temperature of 80-200 DEG C. After the coal layer is heated,
desorption speed of gas is increased, the
free gas is increased to cause increase of gas volume of the coal layer, so
gas pressure is increased and gas extraction rate of gas of the coal layer in the negative-pressure extraction drilled hole is increased favorably.