Method and apparatus for improving energy efficiency in existing gas turbine combined cycle plants
OwnerAri Löyttyinventor
Life of this patent
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Abstract
A method and apparatus for improving the energy efficiency of an existing gas turbine combined cycle plant, which includes a gas turbine having a compressor that pressurizes combustion air which is combusted with fuel in a combustion chamber to form combustion gases. The compressor is followed by a turbine, a high temperature heat exchanger, a low temperature heat exchanger, and a secondary process steam turbine II. Water from the secondary process steam turbine II is condensed in a following condenser-heat exchanger, pressurized by a following pump, and then is vaporized.
Claims28
A method for improving the energy efficiency of an existing gas turbine combined cycle plant, the existing gas turbine combined cycle plant comprising:
- a gas turbine including a compressor that pressurizes combustion air which is combusted with fuel in a combustion chamber to form combustion gases, the compressor followed by a turbine and a high temperature heat exchanger, the combustion gases flowing to the turbine and the high temperature heat exchanger, a secondary process steam turbine II wherein water from the secondary process steam turbine II is condensed in a following condenser-heat exchanger, pressurized by a following pump, and then is vaporized, the method comprising;
- condensing heat of steam contained by the combustion gases in 1 atm pressure and formed in the combustion chamber wherein the condensed heat of steam is used for,
- increasing at a first low temperature heat exchanger an enthalpy of a circulation steam of a Rankine process at a pressure of less than 1 bar by 100 to 350 kJ/kg in constant temperature after a combined first steam turbine and second steam turbine and/or
- vaporizing at the second low temperature heat exchanger liquid additional water fed to the Rankine process circulation in a pressure below 1 bar that is combined with a main Rankine circulation only at a pressure below 1 bar after the combined first steam turbine and second steam turbine,
- after which, reheating a total steam mass flow in the first low temperature heat exchanger before the steam turbine II by using the heat energy from a portion of the combustion gases wherein the combustion gases are split after the high temperature heat exchanger to provide the portion of the combustion gases.
An apparatus for improving the energy efficiency of an existing gas turbine combined cycle plant, comprising:
- a gas turbine including a compressor that pressurizes combustion air which is combusted with fuel in a combustion chamber to form combustion gases, the compressor followed by a turbine and a high temperature heat exchanger, the combustion gases flowing to the turbine and the high temperature heat exchanger,
- a secondary process steam turbine II wherein water from the secondary process steam turbine II is condensed in a following condenser-heat exchanger, pressurized by a following pump, and then is vaporized,
- wherein condensing heat of steam contained by the combustion gases in 1 atm pressure and formed in the combustion chamber is used for,
- increasing at a first low temperature heat exchanger an enthalpy of a circulation steam of a Rankine process at a pressure of less than 1 bar by 100 to 350 kJ/kg in constant temperature after a combined first steam turbine and second steam turbine and/or
- vaporizing at a second low temperature heat exchanger liquid additional water fed to the Rankine process circulation in a pressure below 1 bar that is combined with a main Rankine circulation only at a pressure below 1 bar after the combined first steam turbine and second steam turbine,
- subsequent to a total steam mass flow is reheated in the first low temperature heat exchanger before the steam turbine II by using the heat energy from a portion of the combustion gases wherein the combustion gases are split after the high temperature heat exchanger to provide the portion of the combustion gases.
Dependencies are inferred from the claim text.