Method for controlling H2/CO ratio of in-situ coal gasification product gas

摘要

A method for in-situ coal gasification to recover a product gas having a predetermined H2/CO ratio by introducing controlled amounts of carbon dioxide recovered from the product gas along with steam and oxygen injected into the coal deposits. The H2/CO ratio of the product gas is preferably maintained within the range of 1.5 to 4.0.