Thermal power generation system and method using supercritical carbon dioxide as working fluid

Patent metadata

Field	Value
Publication number	US-9828882-B2
Application number	US-201314081500-A
Country	US
Kind code	B2
Filing date	Nov 15, 2013
Priority date	Feb 1, 2013
Publication date	Nov 28, 2017
Grant date	Nov 28, 2017

Abstract

A thermal power generation system includes a combustor burning oxygen and fuel with supercritical CO 2 , a turbine driven by the supercritical CO 2 and water vapor fed from the combustor, a low-pressure supercritical CO 2 storage storing low-pressure supercritical CO 2 from the turbine, a compressor compressing the low-pressure supercritical CO 2 , a high-pressure supercritical CO 2 storage storing high-pressure supercritical CO 2 from the compressor, and a high-pressure supercritical CO 2 feeder supplying between the high-pressure supercritical CO 2 storage and the combustor, in which the high-pressure supercritical CO 2 feeder supplies the high-pressure supercritical CO 2 to the combustor at a constant pressure. Thus, the thermal power generation system can perform adjustment of an electric power supply required to use unstable renewable energy sources such as solar and wind power, can achieve high efficiency power generation with high temperature working fluid, and can reduce emissions of environmental load substances such as NO x and CO 2 .

First claim

What is claimed is:

1. A thermal power generation system which uses supercritical carbon dioxide as a working fluid, the thermal power generation system comprising:
a combustor which burns oxygen and fuel with the supercritical carbon dioxide;
a supercritical CO 2 turbine which is driven by the supercritical carbon dioxide and water vapor supplied from the combustor;
a supercritical CO 2 turbine generator which is driven by the supercritical CO 2 turbine;
a low pressure CO 2 storage which stores low pressure carbon dioxide emitted from the supercritical CO 2 turbine;
a supercritical CO 2 compressor which compresses the low pressure carbon dioxide;
a high pressure supercritical CO 2 storage which stores high pressure supercritical carbon dioxide obtained by having the supercritical CO 2 compressor compress the low pressure carbon dioxide;
a high pressure supercritical CO 2 feeder which supplies the high pressure supercritical carbon dioxide in the high pressure supercritical CO 2 storage to the combustor;
a supercritical CO 2 compressor drive motor which drives the supercritical CO 2 compressor;
a power fluctuation sensor which detects fluctuation of electric power with varying electric power supply; and
a supercritical CO 2 compressor control unit configured to drive the supercritical CO 2 compressor drive motor and configured to: (i) increase an output of the supercritical CO 2 compressor to the high pressure supercritical CO 2 storage when the detected fluctuation of the electric power is an increase in the varying electric power supply or (ii) decrease the output of the supercritical CO 2 compressor to the high pressure supercritical CO 2 storage when the detected fluctuation of the electric power is a decrease in the varying electric power supply,
wherein the high pressure supercritical CO 2 feeder supplies the high pressure supercritical carbon dioxide to the combustor at a constant pressure,
wherein the supercritical CO 2 compressor has a rotary shaft independent from the supercritical CO 2 turbine, and
wherein the high pressure supercritical CO 2 storage is arranged between the supercritical CO 2 compressor and the supercritical CO 2 turbine.

2. The thermal power generation system according to claim 1 ,
wherein the low pressure carbon dioxide is supercritical carbon dioxide, and
the low pressure CO 2 storage stores low pressure supercritical carbon dioxide.

3. The thermal power generation system according to claim 1 , further comprising:
a regenerated heat exchanger which supplies exhaust heat of the supercritical CO 2 turbine to high pressure supercritical carbon dioxide before being fed to the combustor.

4. The thermal power generation system according to claim 1 ,
wherein the supercritical CO 2 compressor includes an intercooler.

5. The thermal power generation system according to claim 1 , further comprising:
a heat storage which stores heat generated in the supercritical CO 2 compressor; and
a heat storage type heat exchanger which supplies heat stored in the heat storage to high pressure supercritical carbon dioxide before being fed to the combustor.

6. The thermal power generation system according to claim 1 , further comprising:
a secondary heating heat exchanger which supplies exhaust heat of the supercritical CO 2 turbine to supercritical carbon dioxide in a secondary system; and
a secondary supercritical CO 2 closed cycle which includes a secondary supercritical CO 2 turbine which is driven with the secondary supercritical carbon dioxide heated by the secondary heating heat exchanger, a secondary cooler which cools the exhaust of the secondary supercritical CO 2 turbine, and a secondary supercritical CO 2 compressor which compresses the carbon dioxide cooled by the secondary cooler.

7. A method for generating thermal electric power comprising the steps of:
compressing carbon dioxide in a low pressure CO 2 storage by a supercritical CO 2 compressor driven with electric power with varying electric power supply to supply the compressed carbon dioxide to a high pressure supercritical CO 2 storage;
driving the supercritical CO 2 compressor drive motor and (i) increasing an output of the supercritical CO 2 compressor to the high pressure supercritical CO 2 storage when detected fluctuation of the electric power is an increase in the varying electric power supply or (ii) decreasing the output of the supercritical CO 2 compressor to the high pressure supercritical CO 2 storage when detected fluctuation of the electric power is a decrease in the varying electric power supply;
supplying high pressure supercritical carbon dioxide in the high pressure supercritical CO 2 storage to a combustor at a constant pressure;
burning oxygen and fuel with the constant pressure supercritical carbon dioxide serving as a working fluid in the combustor;
generating rated power by a generator coupled to a supercritical CO 2 turbine which is driven with the supercritical carbon dioxide and water vapor supplied from the combustor; and
storing low pressure carbon dioxide obtained by removing water from exhaust of the supercritical CO 2 turbine, and
wherein the high pressure supercritical CO 2 storage is arranged between the supercritical CO 2 compressor and the supercritical CO 2 turbine.

Assignees

• Mitsubishi Hitachi Power Sys

Inventors

• Numata Shohei
• Nakano Susumu
• Shibata Takanori
• Araki Hidefumi

Classifications

• F02C3/30

  Adding water, steam or other fluids {for influencing combustion, e.g. to obtain cleaner exhaust gases (F02C7/141, F02C7/30, F01D21/00, F01K21/04, F23D11/10 take precedence)} · CPC title

• F02C6/18

  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

• F01K25/103

  Carbon dioxide (F01K25/065 takes precedence) · CPC title

• Y02E50/11

  Cross-Sectional Technologies · mapped topic

• Y02E20/16

  Combined cycle power plant [CCPP], or combined cycle gas turbine [CCGT] · CPC title