RU2804173C1 - Combined heat and power generation plant - Google Patents

Abstract

FIELD: thermal power engineering.

SUBSTANCE: invention can be applied in autonomous power supply and heat supply systems, in emergency power supply systems in the presence of heat generated in hot water boilers or other heat sources. Combined heat and power generating power plant, consisting of a hot water boiler of a water heating boiler house or district heating station (DHS), connected through an automatic flow controller to a network water circuit, including a primary hot network water path connected to heat consumers, and a return network water path connected to with a network water pump, and to a circuit with a low-boiling working fluid (LBWF), including a power plant, a steam separator, a turbine, an electric generator, an evaporator (steam generator), a feed pump, a condenser located in the return network water path, providing its primary heating, is additionally equipped a surface heat exchanger that provides additional heating of the return network water with the LBWF liquid phase, connected to the LBWF circuit after the separator and to the return network water path, as well as controlled by the LBWF automatic flow controller.

EFFECT: invention makes it possible to ensure the autonomy of the power supply of a hot water boiler house (or DHS), its energy efficiency and maneuverability; guarantee the functioning of the boiler house as a source of cheap electricity.

1 cl, 1 dwg

Description

Field of technology

The invention relates to the field of energy and can be used to ensure fuel efficiency of combined power supply and heat supply systems using heat generated in water heating boiler units, IPC F01K 17/02.

State of the art

Known combined heat and power supply installations consist of a hot water boiler of a district thermal station (RTS) connected to a network water circuit, including a primary hot network water path connected to heat consumers, and a return network water path connected to a network water pump, and power plant operating according to the organic Rankine cycle (ORC) on a low-boiling working fluid (LBWF), including an evaporator (steam generator), a turbine with an electric generator, a pump and a condenser-heater, and the evaporator is connected through shut-off and control valves to the primary hot network water circuit, and condenser-heater - to the return network water path. In these installations, the LCRT at the exit from the evaporator usually represents slightly superheated or saturated steam. In the case of ORC with the output of wet steam NKRT from the evaporator of the required steam content, the settings are known (Features Design of Organic Rankine Cycle Journal of Siberian Federal University. Engineering & Technologies, 2019, 12(6), 733-745 Denis I. Karabarin and Sergei A. Mihailenko ; Steam generation unit for the organic Rankine cycle. Authors A.V. Dmitrenko, A.V. Kostin. Utility model patent No. 213839, dated 09/30/2022), in which a separator is added after the evaporator to separate the NKRT steam from its liquid phase and subsequent supply of steam to the turbine.

The closest analogue is a combined heat and power generating power plant (Utility model patent No. 151465. Authors Bezrukikh P.L., Polivoda F.A. et al. dated April 10, 2015), consisting of at least two parallel-connected water heating boilers of a district heating stations (RTS), one of which is a peak one, connected to the network water circuit, including a primary hot network water path connected to heat consumers, and a return network water path connected to the network water pump(s) and to a circuit with a low-boiling working fluid (NKRT), including a power plant, turbine, electric generator, condenser, steam generator, feed pump. The peak boiler is connected to the return network water path through a controlled automatic flow regulator connected to a condenser, and the condenser is located in the return network water path.

The disadvantage of this installation is its low thermal efficiency and maneuverability. Steam generation in the evaporator of the power plant is carried out using the heat of the primary network water only at its peak temperature from the peak hot water boiler.

Disclosure of the Invention

The technical objective of the invention is to increase the thermal efficiency of the RTS, as well as to increase the maneuverability and reliability of the power plant.

The technical result achieved by using the invention is an increase in the temperature of the network water at the inlet to the boiler and the ability to operate the ORC turbine both in stationary mode and at variable load.

The specified technical result is achieved by adding to the installation an automatic flow regulator NKRT, which, in combination with the network water flow regulator, ensures that the wet steam output from the NKRT evaporator of the required value of steam content and flow rate necessary for turbine operation both at variable load and in stationary mode, as well as by adding a surface heat exchanger installed in series behind the condenser along the direction of return network water, providing its additional heating of the NKRT in the liquid phase at the boiling point of the NKRT in the evaporator.

Brief description of the drawing

In fig. Figure 1 shows a schematic diagram of a combined heat and electricity generating power plant.

1 - hot water boiler;

2 - primary network water path;

3 - heat consumers;

4 - return network water path;

5 - network water pump;

6 - evaporator (steam generator) ORC;

7 - ORC turbine;

8 - electric generator;

9 - ORC feed pump;

10 - ORC capacitor;

11 - separator;

12 - surface heat exchanger;

13, 14, 15 - shut-off and control valves;

16 - automatic flow regulator NKRT;

17 - automatic regulator of network water flow.

Carrying out the invention

The operation of a combined heat and electricity generating power plant is carried out as follows.

Hot network water from boiler 1, with valve 13 closed and valve 14 open, flows to the evaporator (steam generator) ORC 6, where it transfers part of its heat to generate NKRT steam. Next, partially cooled network water is supplied through path 2 to heat consumers 3. After the consumers, the used return network water is supplied through path 4 to network pump 5, and then to the ORC condenser 10, where it is heated by NKRT steam that has passed through the turbine. Next, the heated return network water enters the surface heat exchanger 12, where the LCRT is additionally heated in the liquid phase, after which it is sent to the entrance to the boiler 1.

The NKRT circulating in the circuit of the power plant is heated by hot network water in the evaporator 6, boils and leaves it in the state of wet steam with the required vapor content. Next, the wet steam enters the separator 11, in which the vapor phase is separated from the liquid phase. Saturated steam from the separator is sent to turbine 7, where it expands and produces useful work. Turbine 7 is equipped with an electric generator 8, which generates electricity to cover the own needs of the RTS and third-party consumers. After the turbine, the exhaust steam from the NKRT enters the condenser, where it heats the return network water and condenses. The liquid phase of the NKRT, which has a temperature higher than the temperature of the exhaust steam of the NKRT, after the separator is sent to the surface heat exchanger 12, where it additionally heats the return network water entering the boiler. After heat exchanger 12, the cooled NKRT is mixed with NKRT from the condenser 10 and returned to the evaporator 6.

Additional heating of return network water in heat exchanger 12 allows you to increase its temperature at the inlet to the boiler and thereby increase the thermal efficiency of the boiler. Automatic regulators of network water flow 17 and NKRT 16 make it possible to increase the maneuverability of the power plant by changing both the flow of network water through the evaporator and the NKRT flow through the ORC circuit, thereby ensuring operation of the turbine both with variable load and in stationary mode.

Claims (1)

Combined heat and electricity generating power plant, consisting of a hot water boiler of a hot water boiler house or district thermal station (RTS), connected through an automatic flow regulator to the network water circuit, including a primary hot network water path connected to heat consumers, and a return network water path connected with a network water pump, and to a circuit with a low-boiling working fluid (LCWF), including a power plant, a steam separator, a turbine, an electric generator, an evaporator, a feed pump, a condenser located in the return network water path, providing its primary heating, characterized in that it equipped with an additional surface heat exchanger that provides additional heating of network water with the liquid phase of the NKRT, connected to the NKRT circuit after the separator and to the return network water path, as well as a controlled automatic flow regulator of the NKRT.

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