Underground coal seam energy extraction system - uses inductive heating with various arrangements for windings of underground coil

摘要

The energy extraction system for underground coal seams uses an inductive coil to heat a given zone, fed from an a.c. source, connected to a frequency converter and a wave shaper in turn connected to the primary coil of a transformer. The secondary, which is connected to the underground coil, includes a variable capacitor in series with one connection. The heat generated enables the selected zone to be heated to a given temperature for a period of time which enables liquid hydrocarbon and other products to be extracted. The coils can be in helical or toroidal form. The turns of the coils can be made up of elements which approximate to a helix or a toroid, or a quasi toroidal shaped may be formed. The ratio of the outside to the inside radius is between 2:1 and 10:1, preferably 5:1.