Patent ID: 8061117
Filing Date: 2011-11-22
Classification: F23L,F23N,F23R

Abstract:
1. An apparatus sustaining flame stability and countering flame-out in transient conditions in a gas turbine combustion system having a main control system, wherein: said gas turbine comprises: a diluent source, a diluent flow rate control unit receiving diluent from said diluent source and delivering diluent at a controlled rate, a fuel source, and a diluent-fuel mixer receiving diluent through said diluent flow rate control unit and fuel from said fuel source, said mixer being configured to homogenously mix the received diluent and fuel to thereby provide a homogeneous mixture thereof, a combustor having a flame zone, and a coupling between said mixer and said combustor configured to introduce said mixture into said flame zone for combustion; and said apparatus sustaining flame stability and countering flame-out comprise the following elements operable autonomously of the gas turbine combustion system main controls: one or more measuring elements configured to measure parameters of said diluent and said fuel prior to and after the mixing thereof by said mixer; a programmed, computer-implemented dynamic control unit communicating with said one or more measuring elements and with said diluent flow rate control unit, said dynamic control unit being configured to accept measurements from said measuring elements as inputs; said programmed, computer-implemented dynamic control unit being further configured to use said measurements to respond to transient conditions through dynamically changing diluent-to-fuel ratios to thereby maintain diluent-to-fuel ratios countering flame-out by: (a) during shutdown procedures and prior to complete shutdown of the gas turbine combustion system, gradually decreasing the diluent flow mixing with said fuel until there is no diluent flow into the gas turbine combustion system, and thereafter following a time delay to complete the shutdown procedures of the combustion system; and (b) during startup procedures of the gas turbine combustion system, to delay the flow of said diluent into the gas turbine combustion system and then gradually increase the flow of diluent into the combustion system and thereby stabilize the combustion process until the combustion system reaches steady-state operation with; said programmed, computer-implemented dynamic control unit being still further configured to control the flow of diluent to the combustion zone in steady-state operation of said gas turbine to maintain a diluent-to-fuel ratio of said homogenized mixture producing NO