Cryogenic injection to control a coal waste bank fire

摘要

Cryogenic injection, a heat transfer method for extinguishing a subsurface fire, was tested at a bituminous coal waste bank in Midvale, OH. A slurry composed of CO_2 particles in liquid N_2 at a temperature of - 180℃, when injected into heated zones, absorbs heat. Conversion of the slurry to a gas creates a cold pressure front that forces heated combustion gases out of the bank. The waste bank had been burning for approximately 30 years. The 5000-m~2 (1.2 acre) site was characterized by a three-dimensional array of temperature measuring points. Temperatures were measured over a 30-month period, before during and after two tests of cryogenic injection. The amount of cryogenic slurry injected was insufficient to completely extinguish the fire, but evaluation of the temperature profiles indicated that it had cooled localized hot spots and promoted ambient cooling of the more widely disbursed heated areas within the bank.