RU2631961C1 - Method for operation of binary combined cycle power plant - Google Patents

Abstract

FIELD: power industry.

SUBSTANCE: invention can be used at heat power plants, namely in the operation of binary combined cycle of heat and power plant (CCHPP). The exhaust gases of the gas turbine plant enter the waste-heat boiler, the steam processed with the waste-heat boiler is then fed to expand and complete work in the heating steam turbine. The reduced steam from the reduction-cooling plant (RCP) is used for heating and deaeration of chemically treated water of the heating network feed, a part of the steam from the steam turbine heat extraction is diverted to the upper and lower network heaters for heating the network water. The rest part of the steam is sent to the condenser, the condensate from which is pumped to the waste-heat boiler. The exhaust gas of the waste-heat boiler is used for heating chemically purified water of the heating network in the gas-water heater, the steam flow is reduced through the reduction-cooling plant (RCP), thereby increasing the steam fed in the flow part of the steam turbine.

EFFECT: invention enables to increase electric power of binary combined cycle power plant.

1 tbl, 1 dwg

Description

The invention relates to the field of thermal energy and can be used in thermal power plants, namely in the operation of a binary combined cycle gas turbine power plant (PTU-CHP).

A known method of operation of a combined heat and power plant, superstructured with a combined-cycle gas unit with a double-circuit waste heat boiler [Patent for invention No. 2349763, IPC F01K 23/06. The way the combined heat and power plant / Remezentsev AB, Sorokin VN, Sheludko LP]. A part of the steam stream generated in the steam boiler of the combined heat and power plant is replaced by the steam generated in the first circuit of the double-circuit waste-heat boiler. In cogeneration sampling of a cogeneration steam turbine, cogeneration plants supply low pressure steam from a double-circuit recovery boiler with lower specific fuel costs per unit of generated energy. The remainder of the steam of high pressure regenerative and heat recovery units is expanded in a steam turbine with additional work. The invention allows to reduce the specific fuel consumption for electric and thermal energy generated at the combined heat and power plant built up with a combined-cycle unit, increase its thermal efficiency, use the available reserves in the power of its cogeneration steam turbines and increase their operating power and electricity generation. However, this method is applicable only when upgrading existing heat and power plants by adding them with a combined-cycle gas unit with a double-circuit recovery boiler.

A known method of operation of a binary combined cycle plant [Shelygin B.L., Moshkarin A.V., Malkov E.S. Determination of the conditions for using as an oxidizing agent the gases leaving the waste heat boiler for burning additional fuel / Bulletin of IHEU. - 2012. - Issue. 2 - S. 4-7], in which it is proposed to sequentially install in the flue of the recovery boiler (KU) behind the gas condensate heater (GPC) an additional fuel combustion chamber (KSDT) and a gas network water heater (GPSV). Considering the temperature of the exhaust gases at the outlet of the recovery boiler 95 ÷ 110 ° C, as well as the high oxygen content, it is proposed to use them as an oxidizing agent for burning fuel in the additional fuel combustion chamber. The additional thermal power generated in this case is used to heat hot network water for the needs of heating in a gas network water heater.

The disadvantage of this method of operation is that it has not been considered the possibility of additional use of the heat of the flue gases of the recovery boiler for heating make-up water of the heating system, and thereby, reducing steam consumption for own needs and generating additional electric power. In addition, there is a need to reconstruct the waste heat boiler due to the installation of KSDT and GPSV behind its last heating stage. Capital expenditures for the reconstruction of KU include the cost of finned tubes, burners, lining of KSDT, auxiliary equipment, as well as construction and transportation costs.

There is a known method of operation of a heating cogeneration unit of a waste type or a technical unit with a low-pressure steam generator [Arsenyev L.V. etc. Combined installations with gas turbines, L., Mechanical Engineering, 1982, p. 32-33, fig. 1.10], containing a gas turbine unit and a steam turbine unit with a backpressure steam turbine. The exhaust gases after GTU and fossil fuels are fed into the furnace of the energy boiler, the steam generated by the energy boiler is sent to expand and perform work in the backpressure steam turbine, the steam from the last stage of the backpressure steam turbine is sent to the production or heat consumer, the exhaust gases after the energy boiler are cooled with feed water into gas-water heater. The method allows to increase the temperature of the feed water, which leads to a decrease in the consumption of organic fuel supplied to the furnace of the energy boiler.

The disadvantage of this method is that it has not been considered the possibility of generating additional electric power of a steam turbine, due to the use of the heat of the exhaust gases of the energy boiler to heat the feed water and displace the steam turbine.

A known method of operation of a binary gas-steam installation with a waste heat boiler [Arseniev L.V. and others. Combined installations with gas turbines, L., Engineering, 1982, Fig. 11.1a, b, c] according to which the GTU exhaust gases are sent to the recovery boiler, the steam generated by the recovery boiler is then fed to the steam turbine for expansion and operation, the spent steam after the steam turbine is sent to the condenser, the condensate is pumped from the condenser to the recovery boiler, the flue gases after the recovery boiler are cooled with condensate in a gas-water heater. The method allows to reduce the temperature of the flue gases and increase the efficiency of the binary gas-steam installation.

The disadvantage of this method is that it has not been considered the possibility of generating additional electric power of a steam turbine, through the use of the heat of the exhaust gases of the recovery boiler for heating make-up water of the heating system, condensate or network water and crowding out the steam turbine.

A known method of operation of a maneuverable steam turbine unit with peak gas turbine [Arsenyev L.V. et al. Combined installations with gas turbines, L., Mechanical Engineering, 1982, p. 86-87, 98-100 fig. III.10], according to which the exhaust gases after the gas turbine are sent to the gas heater of the 1st stage to heat the feed water and generate steam in the energy boiler for expansion and completion in the heating steam, part of the steam from the heat recovery taps of the steam turbine is sent to the upper SP2 and lower SP1 network heaters for heating the mains water, the rest of the steam is sent to the condenser, the condensate from the condenser is sent by the condensate pump to the gas heater of the 1st stage for heating the feed water, while start heating of the network water in the gas network heater (gas heater 2 stages), installed separately from the gas heater 1 stage after the upper network heater SP2, flue gases after the gas heater 1, while reducing the steam extraction to the upper network heater and lower network heater and increase the pass steam to the condenser of a steam turbine. The method allows to increase the electric power of a steam turbine due to a more complete utilization of GTU flue gases.

The disadvantage of the analogue is that the necessary heating of the feed and network water, the decrease in temperature of which is due to the disconnection of the corresponding steam extraction, is provided in gas heaters only due to the heat of the exhaust gases of the gas turbine; the flue gases of the energy boiler are not used to heat make-up water of the heating system, feed and mains water, displace steam turbine take-offs and generate additional electric power, but are discharged into the chimney.

A known method of operation of a steam turbine thermal power station [Patent for invention RU No. 2287703, IPC F01K 17/02. The method of operation of a thermal power plant / Zamaleev M.M., Tsyura D.V., Sharapov V.I.]. Of the first three selections of the T type cogeneration turbine, steam is diverted to high pressure regenerative heaters, and of the last four to low pressure regenerative heaters, in which the main condensate after the turbine condenser and feed water are successively heated. From the seventh and sixth selections of type T turbines, steam is diverted to heat the network water in the lower and upper network heaters, respectively. In the steam-water source water heater for replenishing the heating system, the source water is heated before chemical water treatment by supplying a heating medium, which is used as a fifth-type steam turbine of type T with heating steam extraction. The method allows to provide the required heating of the source water to feed the heating system before chemical water treatment due to the use of a low-grade fifth selection of a T turbine with heating steam extraction as a heating medium in a steam-water heater

The disadvantage of the analogue is that in the known method of operation does not use the excess heat of the exhaust gases of the boiler unit. In addition, this method is applicable only to steam turbine units of thermal power plants.

There is also a known method of operating a peak boiler room [Patent for invention RU No. 2184315, IPC F22D 1/00, IPC F24H 1/00. Peak boiler room / Sharapov V.I., Orlov M.E., Rotov P.V.]. The heat of the flue gases of the boiler is used to heat the source water and deaerated make-up water, part of which, after heating, is used as the heating agent of the vacuum deaerator.

However, this invention is applicable to increase the efficiency of only hot water boiler plants.

The closest analogue is the method of operation of a thermal power plant [Patent for invention RU No. 2309263, IPC F01K 17/02. Thermal power station / Zamaleev M.M., Makarova E.V., Sharapov V.I.], containing a gas turbine unit (GTU), a steam boiler, to which an oxidizer duct is connected - exhaust gases of a gas turbine, located in series in the lowering duct of the boiler along the gases, convective superheater, water economizer, gas-water high-pressure heater and gas-water low-pressure heater, cogeneration steam-turbine unit with heating and regenerative steam extraction, condenser, upper and lower network heaters connected via heating medium to the heating steam extraction of the steam turbine unit, a high pressure deaerator connected by a pipeline of deaerated feed water through the feed pump to the gas-water high-pressure heater of the steam boiler. In addition, a low-pressure gas-water heater is included in the deaerated water circulation circuit in front of the water-water heat exchanger, which is connected via a heated medium to the demineralized water pipe after chemical water treatment. The method allows to provide the required heating of demineralized water in front of the atmospheric deaerator due to the use of excess heat of the exhaust gases of the gas turbine.

The disadvantage of the closest analogue is that it is applicable only for steam turbine thermal power plants, modernized gas turbines. In addition, the implementation of this method will require reconstruction of the convective shaft of the steam boiler to accommodate a gas-water high-pressure heater and a gas-water low-pressure heater.

The objective of the proposed technical solution is to develop a method of operating a binary CCPP-CHP that allows using the heat of the exhaust gases of the recovery boiler to heat the make-up water of the heating system, thereby reducing the steam consumption for own needs and to obtain additional electric power on the steam cogeneration turbine of the binary CCP-CHP.

The essence of the claimed invention lies in the fact that in the method of operation of a binary combined cycle heat and power plant, the exhaust gases of a gas turbine plant enter a recovery boiler generated by a steam recovery boiler and then are fed to expand and perform work in a heating steam turbine, reduced steam from a reduction and cooling unit (ROW ) are used for heating and deaeration of chemically purified water to recharge the heating network, part of the steam from the heat recovery samples of the steam turbine is diverted to the upper and lower network heaters for heating Eva of the mains water, the rest of the steam is sent to the condenser, the condensate from which is pumped to the recovery boiler by the condensate pump, the cleaned water of the heating system in the gas-water heater is heated by the waste gases of the recovery boiler, while the steam consumption through the reduction and cooling unit is reduced (ROW ), due to which increase the passage of steam into the flow part of the cogeneration steam turbine.

The technical result of the claimed invention is to increase the electric power of the binary CCGT-CHP plant by increasing the electric power of the steam turbine unit as a part of the binary CCGT-CHP plant, achieved by additional steam passage to the flow part of the steam turbine, and then to the condenser, by reducing the steam consumption through the reduction and cooling unit ( ROW) for heating the make-up water of the heating system, due to a more complete utilization of the heat of the exhaust gases after the recovery boiler in a gas-water heater n of the make-up water of the heating system installed instead of the steam-water heater.

The invention is illustrated using Fig., Which shows a binary CCGT-CHP scheme that implements the inventive method. The positions in the drawing indicate:

1 - gas turbine installation (GTU);

2 - cogeneration steam turbine;

3 - capacitor PTU;

4 - waste heat boiler (KU);

5 - high pressure drum (VD);

6 - drum low pressure (ND);

7, 8 - continuous blowdown expanders (RNP);

9 - node reduction-cooling installation (ROW);

10 - deaerator KU;

11 - deaerator recharge heating system (DPTS);

12, 13 - feed pumps, respectively, high and low pressure;

14 - pump recharge heating system;

15, 16 - upper and lower network heaters;

17 - thermal consumer;

18 - chemical workshop;

19 - gas-water heater of chemically purified water (GPHOV);

20 - cooler make-up water heating system;

21 - vapor cooler (OB) DGTTS;

22 - raw water heater feed the heating system (PSV-2);

23 - raw water heater of the main condensate (PSV-1);

24 - condensate pump;

25 - high pressure steam pipeline;

26 - pipeline of sharp steam of the recovery boiler;

27 - steam pipeline with RNP 7;

28 - pipe feed main condensate from the chemical shop;

29 - steam pipeline from the low-pressure heating surface of the recovery boiler;

30 - a pipeline of chemically cleaned make-up water of the heating system from a chemical workshop;

31 - pipeline reduced steam;

32 - pipeline evaporator deaerator recharge heating network (DPTS) 11;

33 - drainage pipe cooler vapor 21;

34 - pipeline makeup water heating system;

35 - pipeline of the initial make-up water of the heating network;

36 - heating network;

37 - pipeline of raw water to feed the heating system;

38 - purge water pipeline after RNP 8;

39 - purge water pipeline after RNP 7;

40 - gas turbine generator;

41 - electric generator of a cogeneration steam turbine;

42 - low pressure steam pipeline of the recovery boiler;

43 - network pump;

In - vapor.

The installation for implementing the proposed method includes: a gas turbine 1 connected through an exhaust gas duct to a waste heat boiler 4, which is connected via a hot steam pipeline to a heating steam turbine 2 connected by pipelines to an upper network heater 15 and a lower network heater 16;

a condenser 3, which is connected by an exhaust pipe to a heating steam turbine 2;

a condensate pump 24 for pumping condensate into a waste heat boiler 4;

continuous blowdown expanders 7 and 8, respectively, of high pressure drums 5 and low pressure 6 of the recovery boiler 4;

KU 10 deaerator, connected by a high pressure steam pipeline 25 to a sharp steam pipeline of a recovery boiler 26, a steam pipeline 27 with an RNP 7, a main condensate feed pipe 28 from a chemical workshop 18, a steam pipeline from a low pressure heating surface of a recovery boiler 29,

feed pumps 12 and 13, respectively, of high and low pressures, connected by pipelines to the deaerator 10 and high and low pressure surfaces of the recovery boiler 4;

a gas-water heater of chemically purified water 19, connected by an exhaust gas duct to a recovery boiler 4, pipelines of chemically purified make-up water of a heating network 30 from a chemical workshop 18 and a de-aerator of a heating network 11;

a reduction and cooling unit 9 connected to a low-pressure steam pipeline of a waste heat boiler 42 and a reduced steam pipe 31 with a de-aerator of the heating network 11;

heating network deaerator 11, connected by a reduced steam pipe 31 to the ROW unit 9, vaporization pipes 32 and drainage 33 with a vapor cooler 21, heating network makeup water pipe 34 with heating network makeup pump 14;

a chemical workshop 18 connected by a feed water supply pipe to a heating network 35 with a feed water cooler of a heating network 20 and GGTKHOV 19, and also connected by a main condensate feed pipe 28 with a main condensate raw water heater (PVS-1) 23 and a KU 10 deaerator;

heating water make-up cooler 20, connected to the heating water supply source feed pipe 35 with a raw water heater (PSV-2) 22 and a chemical workshop 18, and also connected to the heating water supply pipe 34 with an NPTS 14 and heating network 36;

raw water heater (PSV-2) 22, connected by a raw water pipeline for replenishing the heating network 37 with a vapor cooler DPTS 21 and with a cooling water make-up cooler 20, and also connected by a purging water pipe 38 with RNP 8;

raw water heater (PSV-1) 23, connected by a pipeline of raw water to feed the main condensate 28 with a chemical workshop 18, and also connected by a pipeline of purge water 39 with RNP 7;

a vapor cooler 21 connected by a raw water pipe for replenishing the heating network 37 with a raw water heater (PSV-2) 22, as well as a vapor pipe 32 of the heating network deaerator 11 and the drain pipe 33; the lower network heater 16, the upper network heater 15, connected by pipelines of the heat network to the network pump 43 and to the heat consumer 17, and also connected by pipelines of steam extraction to the heating steam turbine 2.

The proposed method of operation of a binary CCPP-CHP using a gas-water heater of chemically purified water is as follows.

GTU 1 drives the electric generator 40, which generates electricity. The combustion products after the gas turbine enter the waste heat boiler 4 and, through the use of the heat of the fuel combustion products, generate a steam stream in it, the steam is sent to a heating steam turbine 2, which drives an electric generator 41 that generates electricity. The heating steam turbine 2 has steam withdrawals through pipelines to the network heater upper 15 and the network heater lower 16, for heating the network water of the heating system 36 of the consumer 17. The network pump 43 pumps the network water to the thermal consumer 17. The condensate from the condenser 3 is pumped to the condenser 3 by a condensate pump 24 waste heat boiler 4.

Raw make-up water of the main condensate through the raw make-up water pipeline is heated in PSV-1 by purge water from a continuous purge expander 7 of the high pressure drum 5 of the recovery boiler 4 and enters the chemical workshop 18 for chemical water treatment. Then, the chemically purified make-up water of the main condensate enters the KU 10 deaerator, from where the feed water is pumped by pumps 12 and 13 to the KU 4 high and low pressure circuits.

Through the raw feed water pipe of the heating network 37, the raw makeup water is sequentially heated in the vapor cooler 21 with steam from the DPTS 11, in the raw water heater (PSV-2) 22 with purge water from the continuous blower expander 8 of the low pressure drum 6 of the recovery boiler 4, in the cooler make-up water of heating system 20 after make-up water of DPTS 11 and is supplied for chemical water treatment in chemical shop 18. The cleaned makeup water of the heating system is further heated in a gas-water heater of clean water 19 flue gases KU 4 and at the DPTS 11. The exhaust gases from the exhaust gas duct of the recovery boiler 4 are directed to the gas-water heater of the chemically cleaned make-up water of the heating network 19. At the same time, the minimum allowable temperature of the exhaust gases after the recovery boiler is used when burning gaseous fuel in the combustion chamber of a gas turbine installation 1 from the conditions of low-temperature corrosion of the tail surfaces of the heating, is 80 ° C. Since the temperature of the flue gases at the outlet of the recovery boiler reaches 95 ÷ 110 ° C, an additional amount of heat of the flue gases appears, which is used to heat make-up chemically cleaned water in the heating system in a gas-water heater (GPHOV) 19.

By changing the position of the control valve of the ROW 9 unit, the steam extraction for own needs is reduced. This displaced steam stream is directed to the flow part of the heating steam turbine 2, which leads to an additional increase in the electric power of the heating steam turbine 2. Steam through the ROW 9 unit is sent only to the heating system deaerator (DPTS) 11 to deaerate the chemically cleaned heating network water.

As an example, we consider the method of operation of a binary CCPP-CHP based on a T-56 / 70-6.8 cogeneration steam turbine for the city of Novorossiysk in the medium heating mode. The table shows the results of the calculation of the thermal scheme of a CCGT-CHP plant with heating of additional water to feed the heating system with steam from ROW in a steam-water heater of chemically purified water (PHOV) and flue gases of KU in the State Thermal Processing Plant.

As you can see, the transition to gas heating of make-up water allows to reduce the steam flow through the DOC by 2.85 kg / s. This leads to an increase in the electric power of the cogeneration steam turbine by 1348.5 kW (3.1%).

Thus, the proposed technical solution allows you to:

- heating the chemically cleaned make-up water of the heating system in a gas-water heater due to heat exchange between the flue gases of the recovery boiler and the chemically cleaned make-up water of the heating system;

- unloading the reduction and cooling unit by reducing the amount of steam taken for the preparation of make-up water of the heating system;

- increase the electric power of the cogeneration steam turbine in the binary CCPP-CHP due to the additional passage of steam into the flow part of the turbine, and then to the condenser.

Claims (1)

The method of operation of a binary combined cycle gas turbine power plant, characterized in that the exhaust gases of the gas turbine plant enter the recovery boiler, the steam generated by the recovery boiler is then fed to the heating and recovery steam turbine for expansion and operation, the reduced steam from the reduction and cooling unit (ROC) is used for heating and deaeration of chemically treated water to recharge the heating network, part of the steam from the heat recovery samples of the steam turbine is diverted to the upper and lower network heaters to heat the network water, the rest of the hour steam is sent to the condenser, the condensate from which is pumped to the recovery boiler by the condensate pump, the waste gases of the recovery boiler are heated up the chemically purified water of the heating system in the gas-water heater, while the steam consumption is reduced through the reduction and cooling unit (ROW), due to which increase the passage of steam into the flow part of the cogeneration steam turbine.

Images