GB1537109A - Gas turbine combustion system - Google Patents

Abstract

1537109 Gas turbine engine combustion systems GENERAL ELECTRIC CO 13 Sept 1976 [23 Oct 1975] 37781/76 Heading F1L In an arrangement for burning fluid fuel in a gas turbine combustion system, all of the fuel containing fuel-bound nitrogen (i.e. fuel in which nitrogen atoms are chemically bound into fuel molecules containing at least one element other than nitrogen) being burned in the primary combustion zone near the rich experimental limit for fuel and air (i.e. fuel-rich combustion in which the overall fuel/air ratio is increased until the limit is reached beyond which the flame cannot be maintained). The hot gaseous reaction products from the primary combustion zone are maintained at substantially the adiabatic flame temperature (i.e. that temperature achieved upon completion of the reaction between fuel and air without loss of heat from the reaction system to the surroundings) downstream of the primary combustion zone for at least about 5 milliseconds. Secondary air is then mixed with the hot gaseous reaction products so as to provide an overall fuel-lean mixture and bring about secondary combustion under approximately stoichiometric conditions. Additional air is then introduced and mixed downstream of the previous zone so as to dilute the products of the secondary combustion prior to the entry of the products into the turbine inlet. The fuel molecules referred to in the definition of fuel-bound nitrogen may be ammonia, pyridine, quinoline-typically the nitrogen is chemically bound with carbon, hydrogen and sometimes oxygen in the fuel. For hydrocarbon type fuels the rich experimental limit falls in the range of equivalence ratios (i.e. the fuel/air ratio divided by the stoichiometric fuel/air ratio) between 1À2 and 1À5.