JPH04318207A - Steam turbine exhaust heat power generation equipment - Google Patents

Abstract

PURPOSE:To recover heat taken away by a condenser in a steam turbine plant. CONSTITUTION:The exhaust of a steam turbine 21 is cooled with refrigerant such as ammonia, methyl chloride, propane by a condenser 22 for condensing. The refrigerant is vaporized by the condenser 22, and power generation is executed by a generator 26 by turning an expansion turbine 25 for energy recovery. The refrigerant which leaves the expansion turbine 25 is cooled and condensed by sea water with a heat exchanger 27 to be fed to the condenser again.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power generation system using exhaust heat from a steam turbine power generation plant.

0002

2. Description of the Related Art FIG. 2 is a heat flow diagram of a thermal power generation steam turbine plant. High-temperature, high-pressure steam generated in the superheater 2 of the boiler 1 passes through the main steam stop valve 3 and the steam control valve 4, expands in the high-pressure turbine 5, and is then reheated in the reheater 6. It flows into the intermediate pressure turbine 9 via the intercept valve 8. The exhaust gas of the intermediate pressure turbine 9 is transferred to the low pressure turbine 10.
After being expanded, it flows into the condenser 11 and becomes condensate. Turbines 5, 9, 10 coupled in tandem drive a generator G.

[0003] The condensate is pressurized by a condensate pump 12, heated by extraction air from a low-pressure turbine in a multi-stage low-pressure feed water heater 13, and then dissolved gas in the water is removed by heating in a deaerator 14. Thereafter, the pressure of the water is increased by a feedwater pump 15 driven by a condensing steam turbine, heated by a multi-stage high-pressure feedwater heater 16 by extraction air from a high- and intermediate-pressure turbine, and then supplied to the boiler 1 . The dotted line indicates the drain system of the feed water heater.

0004

[Problem to be solved by the invention] Even in a cutting-edge thermal power plant that uses supercritical pressure steam, the thermal efficiency at the transmission end is 40%.
The condensate loss reaches approximately 45%. this is,
This is because approximately 45% of the combustion heat of the fuel is released to the outside of the system by cooling water obtained by cooling and condensing the turbine exhaust gas.

[0005] Since most of Japan's thermal power plants and nuclear power plants are located on the coast, the above-mentioned cooling water is seawater, and after being used for cooling, it is discharged into the ocean. The amount of water is approximately 150,000 tons per hour per 1 million kW at a thermal power plant.
At nuclear power plants, the amount reaches 250,000 tons per hour per million kW. Large amounts of construction and maintenance costs are required for such large-flow intake and drainage facilities, and high-temperature wastewater can also lead to destruction of the marine environment, so a huge amount of investment is required to take countermeasures. . In very rare cases, there are plants that take water from rivers or use air-cooled condensers, but in either case the condenser loss remains the same, and both construction and maintenance costs are high.

[0006]

[Means for Solving the Problems] In order to solve the above-mentioned conventional problems, the present invention provides a condenser that removes heat from the steam turbine exhaust gas by evaporating the refrigerant and condenses it; An expansion turbine driven by refrigerant gas, a generator driven by the expansion turbine, a refrigerant-seawater heat exchanger that removes heat from the refrigerant gas exiting the expansion turbine and condenses it, and a refrigerant-seawater heat exchanger. This invention proposes a steam turbine exhaust heat power generation facility characterized by comprising a storage tank for storing refrigerant liquid condensed in a container, and a pump for circulating the refrigerant.

[0007]

[Operation] The steam turbine exhaust gas that flows into the condenser is deprived of heat by the latent heat of vaporization of the refrigerant liquid, and is further converted into cooling water (seawater).
The water is cooled and condensed. This condensate is pressurized by a condensate pump and supplied to the turbine water supply system.

On the other hand, on the refrigerant side, the refrigerant that first enters the lower part of the condenser in a liquid state is gasified and exits the condenser. Next, it reenters the high-temperature gas phase of the exhaust gas from the upper part of the condenser, where it is heated and pressurized and flows into the expansion turbine. The refrigerant gas expanded in the expansion turbine drives a generator to recover electricity, becomes a gas that easily condenses, flows out of the expansion turbine, and then enters the refrigerant-seawater heat exchanger where it is cooled. It liquefies and accumulates in the refrigerant liquid storage tank. Thereafter, the pressure is increased by the refrigerant pump, and the refrigerant flows into the lower part of the condenser again, repeating the refrigeration cycle.

As described above, in the present invention, the exhaust heat source of the steam turbine is converted into the power of the expansion turbine, and electric power is generated as the final energy. Unlike conventional condensers, no amount of heat is released outside the system, and the only external power required is the refrigerant pump driving power, significantly improving the thermal efficiency of the steam turbine plant.

0010

Embodiment FIG. 1 is a system diagram showing an embodiment of the present invention.

The exhaust gas from the steam turbine 21 flows into the condenser 22, where it is cooled by the latent heat of evaporation of the refrigerant flowing through the pipes, condenses, and collects in a condensate reservoir 23 (hot well). This condensate is pressurized by a condensate pump 24 and supplied to a boiler or reactor evaporator.

On the other hand, the refrigerant liquid that first enters the condensate-rich lower layer of the condenser 22 where condensate and exhaust gas coexist is heated and gasified, exits the condenser, and then enters the condensate-rich lower layer. The gas enters the rich gas phase of the exhaust gas in the upper part of the condenser, is superheated and pressurized, becomes high-temperature, high-pressure gas, and flows into the expansion turbine 25. The expansion turbine 25 drives the generator 26 and expands the refrigerant gas, which becomes easily liquefied and flows into the refrigerant-seawater heat exchanger 2.
Enter 7. There, it is cooled and liquefied, and is stored in the refrigerant liquid storage tank 28. Thereafter, the pressure is further increased by the refrigerant pump 29, and the refrigerant enters the condenser 22, where the refrigeration cycle is repeated.

A gas regulating valve 30 is provided at the inlet of the refrigerant gas expansion turbine, and a cooling water regulating valve 31 is provided at the cooling water inlet of the refrigerant-seawater heat exchanger, respectively, to correspond to a partial load of the steam turbine. Further, reference numeral 32 is a seawater cooling pipe, and seawater is discharged through the condenser 22 as the case requires.

[0014] As the refrigerant, ammonia, methyl chloride, propane, etc., whose relationship between evaporation pressure and temperature, relationship between condensation pressure and temperature, and refrigerating capacity are suitable for the condensing conditions of the steam turbine, are used.

[0015]

According to the present invention, heat loss carried away by cooling water in a steam turbine condenser of a thermal or nuclear power plant is eliminated, and the thermal efficiency of the plant is greatly improved. Additionally, there is no need for cooling water intake/drainage equipment or measures to prevent environmental pollution from hot water, resulting in savings in construction and maintenance costs.

[Brief explanation of drawings]

FIG. 1 is a system diagram of an exhaust heat power generation facility according to an embodiment of the present invention.

FIG. 2 is a heat flow diagram of an example of a conventional steam turbine plant for thermal power generation.

[Explanation of symbols]

21 Steam turbine 22 Condenser 24 Condensate pump 25 Expansion turbine 26 Generator 27 Refrigerant-seawater heat exchanger 28 Refrigerant liquid storage tank 29 Refrigerant liquid pump

Claims (1)

[Claims] Claim 1: A condenser that removes heat from steam turbine exhaust gas by evaporating refrigerant and condensing it; an expansion turbine driven by the refrigerant gas evaporated in the condenser; and power generation driven by the expansion turbine. a refrigerant-seawater heat exchanger that removes heat from the refrigerant gas exiting the expansion turbine and condenses it; a storage tank that stores the refrigerant liquid condensed in the refrigerant-seawater heat exchanger; and a pump that circulates the refrigerant. Steam turbine exhaust heat power generation equipment characterized by being equipped with.