Combined power generation system employing pressure difference power generation

Patent metadata

Field	Value
Publication number	US-11261783-B2
Application number	US-201816143401-A
Country	US
Kind code	B2
Filing date	Sep 26, 2018
Priority date	Oct 30, 2017
Publication date	Mar 1, 2022
Grant date	Mar 1, 2022

Abstract

A combined power generation system improves the generation efficiency of a pressure difference power generation facility by using at least one of air for cooling a turbine of a gas turbine power generation facility and waste heat of flue gas generated by the gas turbine power generation facility. Working fluid to be used in a supercritical fluid power generation facility is cooled by using cold energy of liquefied natural gas. The system includes an air discharge channel via which compressed air is discharged; a fuel gas heater for heating the natural gas to be introduced into the pressure difference power generation facility by performing a heat exchange between the discharged air and the natural gas being heated; and a cooling air inflow channel for guiding the cooled air passed through the fuel gas heater to a turbine of the gas turbine power generation facility.

First claim

What is claimed is:

1. A combined power generation system comprising: a pressure difference power generation facility for generating power using a change in pressure of natural gas; a gas turbine power generation facility comprising a compressor that takes in and compresses external air to produce compressed air, a combustor that mixes the compressed air and the natural gas passing through the pressure difference power generation facility and burns the mixture to produce a flue gas, a turbine having turbine rotor configured to be rotated by the flue gas, and a generator configured to be powered by the turbine; an air discharge channel via which a portion of the compressed air produced by the compressor of the gas turbine power generation facility is discharged; a supercritical fluid power generation facility for generating power using a supercritical working fluid heated by the flue gas generated by the gas turbine power generation facility; an LNG heat exchange facility in which heat exchange occurs between the working fluid discharged from the supercritical fluid power generation facility and liquefied natural gas (LNG), so that the working fluid is cooled and the liquefied natural gas is heated to be regasified into natural gas; a fuel gas heater receiving the aft flowing along the air discharge channel and the natural gas produced by the LNG heat exchange facility, the fuel gas heater configured to heat the received natural gas by performing a heat exchange between the received air and the received natural gas, pass the heated natural gas to the pressure difference power generation facility, and pass cooled air to the turbine of the gas turbine power generation facility; a cooling air inflow channel for guiding the cooed air passed through the fuel gas heater to the turbine of the gas turbine power generation facility; a first waste heat recovery heat exchange facility in which heat exchange occurs between the flue gas generated by the gas turbine power generation facility and the working fluid having passed through the LNG heat exchange facility and flowing along a first flow channel; a second waste heat recovery heat exchange facility in which heat exchange occurs between the flue gas generated by the gas turbine power generation facility and a merged stream of the working fluid having passed through the LNG heat exchange facility and flowing along a second flow channel and the working fluid passing through the first waste heat recovery heat exchange facility, the working fluid passing through the second waste heat recovery heat exchange facility being supplied to the supercritical fluid power generation facility; and an air heat exchanger in which heat exchange occurs between the working fluid passing through the LNG heat exchange facility and the cooled air flowing along the cooling air inflow channel, the air heat exchanger having an outlet for passing the working fluid having passed through the LNG heat exchange facility and then through the air heat exchanger; and a transport pipe for transporting supercritical fluid, the transport pipe having a first end connected to the outlet of the air heat exchanger and a second end disposed opposite the first end and connected to the first flow channel.

2. The combined power generation system according to claim 1 , wherein the natural gas resulting from the regasification performed in the LNG heat exchange facility includes:
a first portion that is supplied to the fuel gas heater; and
a second portion that is separate from the first portion and is supplied to consumers.

3. The combined power generation system according to claim 1 , further comprising:
a working fluid heat exchanger in which heat exchange occurs between the working fluid having undergone heat exchange in the LNG heat exchange facility and the working fluid discharged from the supercritical fluid power generation facility.

4. The combined power generation system according to claim 3 , further comprising:
a working fluid flow control valve for regulating flow rates of streams of the working fluid flowing into the first flow channel and the second flow channel,
wherein the working fluid heat exchanger is disposed along the second flow channel between the working fluid flow control valve and the second waste heat recovery heat exchange facility, and
wherein the working fluid passing through the LNG heat exchange facility and then through the air heat exchanger is supplied to the second flow channel between the working fluid heat exchanger and the second waste heat recovery heat exchange facility.

5. The combined power generation system according to claim 1 , further comprising:
a branch channel that connects the air discharge channel with the cooling air inflow channel to allow the portion of the compressed air produced by the compressor of the gas turbine power generation facility to bypass the fuel gas heater; and
a cooling fan installed on the cooling air inflow channel and disposed closer to the turbine of the gas turbine power generation facility than a junction point of the cooling air inflow channel and the branch channel,
wherein the air heat exchanger is installed on the cooling air inflow channel downstream from the cooling fan.

Assignees

• Doosan Heavy Ind & Construction Co Ltd

Inventors

• Kim Sanghyeun
• Sung Hwachang
• Jang Juntae
• Cha Songhun

Classifications

• F02C6/18 Primary

  using the waste heat of gas-turbine plants outside the plants themselves, e.g. gas-turbine power heat plants (using waste heat as source of energy for refrigeration plants F25B27/02; using the waste heat of a gasturbine for steam generation or in a steam cycle see F01K23/10) · CPC title

• F02C6/08

  the gas being bled from the gas-turbine compressor · CPC title

• F02C7/141

  of working fluid · CPC title

• F02C7/224

  Heating fuel before feeding to the burner · CPC title

• F17C1/002

  Storage in barges or on ships · CPC title