Method and system for controlling fuel supply in a combustion turbine engine

Abstract

In order to regulate fuel flow to the combustor () of the combustion turbine engine () having a primary combustion zone () and at least one further combustion zone, the temperature of the inlet and outlet of the combustor () are determined, as are first and second values representing first and second properties, with the first property being one of: the total enthalpy rise in the combustor (), the equivalence ratio of the combustor (), the fuel/air ratio of said combustor (), the fuel flow through the combustor, and the second property being one of: the enthalpy rise in the primary zone (), the equivalence ratio of said primary zone (), the fuel/air ratio of the primary zone(); the temperature rise across the primary zone(), or the fuel flow through the primary zone (). The second property is determined from the first value and the current value of the ratio of the fuel to the primary zone () to the total fuel to the combustor (). The temperature of the outlet of the primary zone () is thus determined from the inlet temperature and the second value, are compared with a predetermined temperature to generate a control signal dependent on the difference. The fuel to the primary zone () is then varied, to vary the control signal to reduce the difference. This use of ratios eliminates the need for a gas chromatograph, flow ratios and humidity sensors to determine the properties of the gas.