Abstract: Disclosed is a method for the underground retorting of oil shale comprising introducing retorting fluid from a first direction into a retort containing rubblized mass comprising oil shale until the mass is substantially retorted; and then introducing oxygen containing gas from a second direction substantially opposite to the first direction to combust with coke or hydrocarbonaceous materials in the rubblized mass and retort a portion of unretorted rubblized mass.

Abstract: Disclosed is a process for the in situ retorting of oil shale and energy recovery from generated off gases. An underground retort containing rubblized oil shale is subjected to retorting, thereby forming shale oil and off gases. The off gases are purified and burned in a gas turbine. Commonly this process comprises forming a subterranean in situ retort containing rubblized oil shale having a void space of about 5 to about 40 percent; passing a retorting gas through the in situ retort to effectively retort the oil shale and produce a mixture of shale oil and off gases; subjecting the mixture of shale oil and off gases to a preliminary separation to remove gross quantities of shale oil from the off gases; passing a portion of the off gases to a purification zone so as to remove off gas impurities which would be detrimental to the environment or the operation of downstream equipment; and passing a portion of the purified off gases to a gas turbine where said off gases are burned and power is generated.

Abstract: Refinery or similar streams containing NH.sub.3 are processed in a sulfur plant having separate burners for the NH.sub.3 -containing acid gas stream and for the NH.sub.3 -free acid gas stream. A sampling device is provided for continuously or periodically sampling the combustion products from the unit burning the NH.sub.3 -containing gas. The H.sub.2 S/SO.sub.2 ratios at this sample point and in the sulfur plant tail gas are used to control the operation of the system.