Method of operating a combined cycle electric power plant

摘要

A method of operating a combined cycle electric power plant at a measuring and regulating station of a gas transmission line is disclosed where gas at high pressure is being delivered from the transmission line to a lower pressure line, such as a gas distribution system, comprising the steps of supplying a portion of the gas to the combustion chamber of a gas turbine to drive a first electrical generator and produce electricity, using the hot gases in the exhaust of the gas turbine to heat water in a boiler and produce steam, supplying the steam to a steam turbine to drive a second electrical generator and produce electricity, reducing the pressure of the gas being delivered to the pressure of the lower pressure line, and using the heat of condensation of the exhaust steam from the steam turbine to keep the temperature of the gas at or above a selected minimum as the pressure of the gas is reduced from that of the high pressure line to the pressure of the lower pressure line. In one embodiment of the method, the pressure of the delivered gas is reduced by passing the gas through a turboexpander and using the output energy of the turboexpander to drive a third electrical generator and produce electricity.