Abstract: A method and apparatus are disclosed for the utilization of energy in gas of low heating value. The low heating value gas is preheated, mixed with an amount of air that will provide oxygen in an amount that will limit the maximum temperature rise in a catalytic combustion chamber to avoid excessive temperatures, and delivered into the catalytic combustion chamber at a temperature exceeding about 400.degree. F. that will cause ignition of the combustibles on contact with the catalyst. In a preferred embodiment, combustion is accomplished in two combustion chambers connected in series with a heat exchanger between the combustion chambers for cooling the combustion products discharged from the first combustion chamber before they are delivered to the next combustion chamber. Approximately fifty percent of the total combustion air is mixed with the combustible gas before delivery into each of the combustion chambers.

Abstract: A method is disclosed for the utilization of energy in gas of low heating value discharged from a production well of an in-situ combustion process for the production of oil. The low heating value gas is mixed with an amount of air that will provide oxygen in an amount that will limit the maximum temperature rise in a catalytic combustion chamber to avoid excessive temperatures regardless of changes in composition of the low heating value gas. The mixture is preheated and delivered into the catalytic combustion chamber at a temperature exceeding about 400.degree. F. that will cause ignition of the combustibles on contact with the catalyst. In a preferred embodiment, combustion is accomplished in two combustion chambers connected in series with a heat exchanger between the combustion chambers for cooling the combustion products discharged from the first combustion chamber before they are delivered to the next combustion chamber.

Abstract: A gas turbine system for the recovery of power from fuel gases having a low heating value, i.e., below about 80 Btu/scf, and usually in the range of 35 to 70 Btu/scf, has an external catalytic combustor. The catalytic combustor is divided into a primary and a secondary catalytic combustion chamber with a heat exchanger between the two combustion chambers. In the preheater the low heating value gas mixed with combustion air is passed in indirect heat exchange with products of combustion from the first combustion chamber before the low heating value gas is delivered to the first combustion chamber. The turbine system is particularly advantageous in recovering power from low heating value gas in which the combustibles are hydrocarbons, primarily methane.