Back to results
US 10,100,680 B2Granted
Combined cycle gas turbine plant comprising a waste heat steam generator and fuel preheating step
AssigneeSiemens Aktiengesellschaft
InventorsJan Brückner, Frank Thomas
Life of this patent
Estimating the term…
Abstract
A combined cycle gas turbine plant and a corresponding method for operating such a combined cycle gas turbine plant, in which, during load operation of the combined cycle gas turbine plant, a water mass flow which is supplied according to the forced-flow principle to a waste heat steam generator is adjusted such that the evaporator heating surface of the medium pressure stage is oversupplied and thus a defined amount of excess water, which is heated in the evaporator heating surface but not vaporized, is discharged via the water-steam separator to a heat exchanger circuit for preheating fuel for the gas turbine.
Claims5
A combined cycle power plant comprising:
- a waste heat steam generator comprising a multiplicity of heating surfaces which are:
- arranged in an exhaust gas duct of a gas turbine;
- and
- wherein the multiplicity of heating surfaces are connected to one another to form a three-stage pressure system, the waste heat steam generator comprising a low-pressure stage, an intermediate-pressure stage and a high-pressure stage for a water-steam circuit of a steam turbine,
- wherein each of the low-pressure stage, intermediate-pressure stage and high-pressure stage comprises respectively at least one heating surface for preheating, for evaporating, and for superheating,
- wherein the intermediate-pressure stage is configured to operate on a once-through principle in which an intermediate-pressure evaporator generates steam in a single pass therethrough and without a steam drum,
- wherein a water-steam separator, which is arranged between an outlet of an evaporator heating surface of the intermediate-pressure evaporator and an inlet of a superheater heating surface of a superheater of the intermediate-pressure stage and in which excess water can be separated from the steam, is provided with a branching-off line for diverting the excess water,
- wherein the branching-off line is connected to a heat exchanger circuit for preheating fuel for the gas turbine such that a defined quantity of excess water separated in the water-steam separator is introduced into the heat exchanger circuit, and
- wherein during load operation the combined cycle power plant is configured to feed a water mass flow to the waste heat steam generator such that the evaporator heating surface of the intermediate-pressure stage is oversupplied and thus the defined quantity of excess water, which is heated but not evaporated in the evaporator heating surface, is diverted via the water-steam separator to the heat exchanger circuit for preheating the fuel for the gas turbine.
6 more elements
A method for operating a combined cycle power plant comprising a waste heat steam generator comprising a multiplicity of heating surfaces which are:
- arranged in an exhaust gas duct of a gas turbine;
- and
- wherein the multiplicity of heating surfaces are connected to one another to form a three-stage pressure system, the waste heat steam generator comprising a low-pressure stage, an intermediate-pressure stage and a high-pressure stage for a water-steam circuit of a steam turbine,
- wherein each of the low-pressure stage, intermediate-pressure stage and high-pressure stage comprises respectively at least one heating surface for preheating, for evaporating, and for superheating, wherein the intermediate-pressure stage is configured to operate on a once-through principle in which an intermediate-pressure evaporator generates steam in a single pass therethrough and without a steam drum, wherein a water-steam separator, which is arranged between an outlet of an evaporator heating surface of the intermediate-pressure evaporator and an inlet of a superheater heating surface of a superheater of the intermediate-pressure stage and in which excess water can be separated from the steam, is provided with a branching-off line for diverting the excess water, wherein the branching-off line is connected to a heat exchanger circuit for preheating fuel for the gas turbine such that a defined quantity of excess water separated in the water-steam separator is introduced into the heat exchanger circuit, the method comprising:
- during load operation of the combined cycle power plant, feeding a water mass flow to the waste heat steam generator such that the evaporator heating surface of the intermediate-pressure stage is oversupplied and thus the defined quantity of excess water, which is heated but not evaporated in the evaporator heating surface, is diverted via the water-steam separator to the heat exchanger circuit for preheating the fuel for the gas turbine.
2 more elements
Dependencies are inferred from the claim text.