SU1740707A1 - Combination thermal power plant - Google Patents

Abstract

The invention relates to a power system and can be used in atomic and thermal power plants using water vapor and low boiling substances as working fluids. The combined heat and power plant is additionally equipped with a closed circuit with a low boiling point substance consisting of a successively located evaporator, a compressor, a heat exchange surface and a turbo detamder with a generator, the heat exchange surface is located in the high-pressure heater of the steam-power circuit, and the evaporator in the heating medium is placed in the main circuit with a low boiling point for heat exchange surfaces. 1 il.

Description

The invention is related to power engineering and can be used at thermal and nuclear power plants, using water vapor and low boiling substances as working fluids.

A thermal power plant is known that regenerates waste heat (Japan, which is a series circuit containing a preheater, steam generator, condenser, and pump).

A turbine plant is known which operates on pairs of a low-boiling working fluid, the heat circuit of which includes a heat exchanger, a turbine, a condenser and soy.

The known method of operation of a binary condensation power plant, which B | C includes, in addition to the elements of the steam power cycle, which uses water as the working fluid, also a turbogenerator, a condenser, a feed pump and a choke operating on low boiling point matter.

The presence of a condenser in a cycle with a low-boiling substance cooled by the environment from the environment calls into question the economic efficiency of the work according to the presented scheme.

First, it is related to that. that the temperature of the water in it is equal to the ambient temperature limits the decrease in the temperature of the low boiling working fluid and, consequently, the electric power of the turbogenerator. If the cycle with low boiling substance was absent, then at the same temperature of cooling water and the condenser the electrical power generated by the turbogenerators would be even greater than the total impedance of the turbogenerators with high boiling and low boiling substances, as steam. withdrawn from turbine outlets, would be involved in power generation, there would be no losses occurring in heat exchangers, as well as associated with additional power consumption for driving the pump in a cycle with low boiling point substance.

Secondly, as a result of the introduction of a source of secondary energy into the cycle after the throttles and before the first heat exchanger after the steam turbine, the low-boiling substance evaporates and overheats. For this reason, the temperature rises to the level of the temperature of the exhaust environment and, as a result, there is no heat exchange or a significant decrease in its efficiency in the first heat exchanger after the steam turbine. In this connection, there is no condensation of the exhaust, and therefore the heat exchanger does not perform its functional load, which entails the impossibility of the operation of the entire steam turbine installation.

Consider the option when we got in the first heat exchanger after the steam turbine. normal heat exchange point of view temperature conditions. This is possible in the case of a significant decrease in the temperature and pressure of the low boiling point substance after the throttles, which entails the problematic operation of the low-boiling substance turbo-generator.

Thus, the essential shortcomings inherent in thermal and nuclear power plants come to the fore. which are heat losses with exhaust steam from a steam turbine; the presence of volumetric cooling ponds or cooling towers; electric power consumption for cooling water pumping; high consumption of fresh water with its growing deficit ..

The purpose of the invention is to increase the efficiency of thermal power plant.

The goal is achieved by those. that the combined heat and power plant, containing a closed steam power circuit running on water and including sequentially placed steam generator, steam turbine with generator. condenser with condensate pump and low and high pressure heaters, as well as a closed circuit operating on low-boiling substance and containing heat exchange surfaces placed in a condenser and low-pressure heater of a steam-power circuit, additionally equipped with an additional closed circuit with low boiling substance consisting of located evaporator, compressor, heat exchange surface and turboexpander with a generator, and the heat exchange surface is placed in the heater about the pressure of the steam power circuit, and the evaporator through the heating medium is located in the main circuit with a low boiling point substance behind the heat exchange surfaces.

The drawing shows the principal thermal scheme of a combined heat and power plant.

The installation contains a closed steam power circuit running on water and including successively placed steam generator 1, steam turbine 2 with generator 3. condenser 4 with condensate pump 5 and heaters of low 6 and high 7 pressure with deaerator 8 placed between them and feed pump 9, as well as a closed loop operating on a low-boiling substance and containing heat exchange surfaces placed in condenser 4 and. a low pressure primary circuit preheater, as well as a compressor 10 and a turbo expander 11 with a generator 12. In addition, the installation is equipped with an additional closed loop with a low boiling point substance consisting of a series of evaporator 13. of a compressor 14. a heat exchange surface placed in a high pressure heater 7 of the steam power circuit, the evaporator 13 in the heating medium being placed in the main circuit with a low boiling point substance behind the heat exchange surfaces.

The work of the combined heat and power plant proceeds as follows.

Par obtained in the steam generator 1. follows the steam turbine 2. which, together with the generator 3, convert thermal energy into electrical energy. The low-temperature waste steam after turbine 2 is condensed in condenser 4. which acts as an evaporator 1 for the refrigerant entering it, in which it evaporates and overheats. The compressor 10 compresses and additionally overheats the refrigerant, the heat from which is transferred partially to the water condensate in the low-pressure preheater, and partially in the evaporator 13. Electric power is generated by the turbo-expander 11 and the generator 12. They close the cold chain of the main circuit with a low boiling point substance.

In the next loop of the refrigeration cycle, the same processes occur as in the previous one. In it, low-grade heat at a higher temperature level evaporates the refrigerant in the evaporator 13. Due to the compression of the refrigerant in the compressor 14, its temperature and pressure increase. The total heat obtained through the evaporator 13 in the compressor 14. is sensed by the high-pressure preheater. The cooled refrigerant expands into the turbo expander 15. It acts as a drive for the generator 16. The feed water thus heated is fed to the steam generator 1.

Claims (1)

Claims of the invention A combined heat and power plant comprising a closed steam power circuit operating on water and including a series-arranged steam generator, a steam turbine with a generator. condenser, condensate pump and low and high pressure heaters, as well as a closed loop operating on a boiling substance and containing heat exchange surfaces placed in a condenser and a low-pressure steam-power preheater, differing in that. what. in order to increase its efficiency, it is equipped with an additional closed loop with a low boiling point substance consisting of successively arranged evaporators, a compressor. a heat transfer surface and a turboexpander with a generator, the heat exchange surface is placed in the high-pressure heater of the steam-power circuit, and the evaporator is placed in the heating medium in main circuit with a low boiling point substance behind heat exchange surfaces