Solar thermal power generation system and solar thermal power generation method

Patent metadata

Field	Value
Publication number	US-10247174-B2
Application number	US-201615195229-A
Country	US
Kind code	B2
Filing date	Jun 28, 2016
Priority date	Jun 30, 2015
Publication date	Apr 2, 2019
Grant date	Apr 2, 2019

Abstract

A solar thermal power generation system includes a solar heat collection system that generates superheated steam by solar heat, a main power generation system that performs power generation by part of the superheated steam generated by the solar heat collection system, a solar heat storage/release system that stores heat in a heat storage medium or releases the heat stored in the heat storage medium, and a secondary power generation system that performs power generation by saturated steam generated by the heat storage or the heat release in the solar heat storage/release system. The solar heat storage/release system includes a heat storage heater for exchanging heat between the rest of the superheated steam generated by the solar heat collection system and the heat storage medium to store heat in the heat storage medium and to generate saturated steam, a low-temperature tank for containing the heat storage medium to be supplied to the heat storage heater, and a high-temperature tank for containing the heat storage medium after the heat storage in the heat storage heater. The secondary power generation system includes a saturated steam turbine into which the saturated steam generated by the heat storage heater can be introduced.

First claim

What is claimed is:

1. A solar thermal power generation system comprising:
a solar heat collection system that uses water/steam as a heat medium, the solar heat collection system being configured to generate superheated steam from water by collecting solar heat;
a main power generation system that uses the heat medium in common with the solar heat collection system, the main power generation system being configured to perform power generation by using part of the superheated steam generated by the solar heat collection system;
a solar heat storage/release system that uses a heat storage medium different from the heat medium of the solar heat collection system, the solar heat storage/release system being configured to store heat in the heat storage medium by heat exchange with the rest of the superheated steam generated by the solar heat collection system and to release the heat stored in the heat storage medium; and
a secondary power generation system that uses the heat medium in common with the solar heat collection system, the secondary power generation system being configured to perform power generation by using the heat medium changed into saturated steam by heat storage or heat release of the heat storage medium in the solar heat storage/release system, wherein:
the main power generation system includes:
a steam turbine into which part of the heat medium from the solar heat collection system is introduced, the heat medium being superheated steam; and
a main generator driven by the steam turbine,
the solar heat storage/release system includes:
a heat storage heater for exchanging heat between the rest of the heat medium from the solar heat collection system and the heat storage medium to store heat in the heat storage medium and to change the heat medium from superheated steam into saturated steam;
a low-temperature tank for containing the heat storage medium to be supplied to the heat storage heater; and
a high-temperature tank for containing the heat storage medium after storing heat in the heat storage heater, and
the secondary power generation system includes:
a saturated steam turbine;
a secondary generator driven by the saturated steam turbine;
a first pipe connected to the solar heat collection system and to an inlet of the heat storage heater, the first pipe being configured to introduce the rest of the heat medium from the solar heat collection system into the heat storage heater, the heat medium being superheated steam; and
a second pipe connected to an outlet of the heat storage heater and to an inlet of the saturated steam turbine, the second pipe being configured to introduce the heat medium from the first pipe through the heat storage heater into the saturated steam turbine.

2. The solar thermal power generation system according to claim 1 , wherein:
the solar heat storage/release system further includes:
a preheater for exchanging heat between water in the secondary power generation system and the heat storage medium to heat up the water by heat release from the heat storage medium; and
an evaporator for exchanging heat between the water heated by the preheater and the heat storage medium supplied from the high-temperature tank to generate saturated steam from the water by heat release from the heat storage medium,
the low-temperature tank contains the heat storage medium from the preheater, and
the saturated steam generated by the evaporator can be introduced into the saturated steam turbine.

3. The solar thermal power generation system according to claim 1 , wherein:
the main power generation system further includes a first steam flow control valve,
the secondary power generation system further includes a second steam flow control valve, and
the first steam flow control valve and the second steam flow control valve control a ratio between a flow rate of the superheated steam to be supplied to the steam turbine and a flow rate of the superheated steam to be supplied to the heat storage heater.

4. The solar thermal power generation system according to claim 1 , wherein the secondary power generation system further includes a bypass system for allowing part of the saturated steam to bypass the saturated steam turbine.

5. A solar thermal power generation method comprising:
changing a heat medium from water into superheated steam by collecting solar heat;
performing power generation by driving a steam turbine with part of the heat medium changed into superheated steam generated by the solar heat;
supplying a heat storage medium contained in a low-temperature tank to a heat storage heater;
introducing a remainder of the heat medium changed into superheated steam by the solar heat into the heat storage heater;
exchanging heat in the heat storage heater between the remainder of the heat medium changed into superheated steam by the solar heat and the heat storage medium supplied from the low-temperature tank to change the heat medium from superheated steam into saturated steam and to store the solar heat in the heat storage medium;
containing in a high-temperature tank the heat storage medium after heat storage in the heat storage heater;
introducing the heat medium changed into saturated steam from the superheated steam by the heat storage heater into a saturated steam turbine; and
performing power generation by driving the saturated steam turbine with the heat medium through the heat storage heater.

6. The solar thermal power generation method according to claim 5 , wherein when the solar heat cannot be collected,
the heat storage medium that has stored heat and is contained in the high-temperature tank is supplied successively to an evaporator and a preheater,
water generated from the saturated steam by the driving of the saturated steam turbine is supplied successively to the preheater and the evaporator,
heat exchange is performed in the preheater between the heat storage medium and the water to heat up the water by heat release from the heat storage medium,
heat exchange is performed in the evaporator between the heat storage medium and the water heated by the preheater to generate saturated steam from the water by heat release from the heat storage medium,
the heat storage medium after the heat release in the preheater is contained in the low-temperature tank, and
power generation is performed by driving the saturated steam turbine with the saturated steam generated in the evaporator.

7. The solar thermal power generation method according to claim 5 , wherein when upward and downward fluctuations of direct normal irradiance occur, a ratio between a flow rate of the superheated steam to be supplied to the steam turbine and a flow rate of the superheated steam to be supplied to the heat storage heater is controlled to maintain a sum total of power generation output of the steam turbine and power generation output of the saturated steam turbine at a substantially constant level irrespective of the fluctuations of the direct normal irradiance.

8. The solar thermal power generation method according to claim 5 , wherein when sharp upward fluctuations of the direct normal irradiance occur, power generation output of the saturated steam turbine is decreased such that a sum total of power generation output of the steam turbine and power generation output of the saturated steam turbine is maintained at a substantially constant level irrespective of the sharp upward fluctuations of the direct normal irradiance by causing part of the saturated steam introduced from the heat storage heater to the saturated steam turbine to bypass the saturated steam turbine.

9. The solar thermal power generation method according to claim 5 , wherein when the direct normal irradiance drops significantly

Assignees

• Mitsubishi Hitachi Power Sys

Inventors

• Mishima Nobuyoshi
• Nagafuchi Naoyuki

Classifications

• F22B1/006

  using solar heat · CPC title

• Y02E60/14

  Thermal energy storage · CPC title

• F01K7/165

  Controlling means specially adapted therefor · CPC title

• F24S60/00

  Arrangements for storing heat collected by solar heat collectors (working fluids forming pools or ponds F24S10/10) · CPC title

• Y02E10/46

  Conversion of thermal power into mechanical power, e.g. Rankine, Stirling or solar thermal engines · CPC title