Improved start-up gas turbine combined cycle plant improved method for starting a relatively low temperature steam turbine

摘要

A method for enhanced cold (or warm) steam turbine start in a supplementary fired multi-gas turbine combined cycle plant is disclosed. Boiler supplementary firing, which is normally used to increase steam flow when the plant gas turbine is at maximum load, is used to augment steam production with a partly loaded, temperature matched gas turbine. This is done to satisfy minimum required steam flow for a cold (or warm) steam turbine start. Lighting the supplementary firing burners in the heat recovery steam generator/boiler and setting them at a minimum or low heat load serves to add enough steam, at the proper temperature, to insure a successful cold or warm steam turbine start when the gas turbine load and related steam production capacity from the gas turbine exhaust flow are limited by the need to match the required steam temperature and/or maintain low gas turbine exhaust emissions.