RU2626710C1 - Method of work of binary steam heat electrocentral - Google Patents

Abstract

FIELD: power industry.

SUBSTANCE: outgoing gases are fed to the recovery boiler after the gas turbine plant. The generated heat recovery boiler steam is then fed to expand and do work in the heating steam turbine of the steam withdrawn from which heats the upper and lower network heaters for heating-system water, the remaining part of the steam to a condenser, the condensate from the condensate pump which pumped into the waste heat boiler, exhaust gases after the recovery boiler is heated demineralized makeup water heating system in a gas-water heater, the exhaust gases after which produce additional heat set oh gazosetevom water heater, installed separately from the recovery boiler after the upper heater network. At the same time, steam consumption through the reduction-cooling unit (RCU) is reduced, which is used only for the direction of the reduced steam to the deaerator of the heating system for deaeration of the chemically cleaned make-up water of the heating network, and increase the steam flow into the flowing part of the steam turbine, and also reduce the steam extraction Network heaters and increase the steam flow into the "tail" part of the low-pressure cylinder of the heat-recovery steam turbine.

EFFECT: increasing the electric capacity of the binary combined-cycle plant of a combined heat and power plant.

1 dwg, 2 tbl

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 (CCGT-CHP).

A known method of operation of a combined heat and power plant, built-in 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 steam turbine thermal power plant [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 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 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.

A known 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 loop in front of the water-to-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 this method 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.

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 - C.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 the 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. and others. Combined installations with gas turbines. L .: Engineering, 1982, p. 32-33, fig. 1.10], containing a gas turbine unit and a steam turbine unit with a backpressure steam turbine. The flue gases after GTU and fossil fuels are fed into the furnace of the power boiler, the steam generated by the power 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 flue gases after the power boiler are cooled by the feed water in a 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. 11.1 a, 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 exhaust steam after the steam turbine is sent to the condenser, condensate is pumped from the condenser by the condensate pump to the recovery boiler, the flue gases after the recovery boiler are cooled by 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 by using the heat of the flue gases of the recovery boiler to heat the make-up water of the heating system, condensate or mains water and displace the steam turbine.

The closest analogue is the method of operation of a maneuverable steam turbine plant with peak gas turbine [Arsenyev L.V. and others. Combined installations with gas turbines. L .: 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 turbine, 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 network 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, at In this case, the 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 selection of steam to the upper network heater and lower network heater and increase Passing steam into 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 caused by the disconnection of the corresponding steam withdrawals, 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.

The objective of the proposed technical solution is to develop a method of operation of a binary CCPP-CHP that allows you to use the heat of the flue gases of the recovery boiler to heat both make-up and network water of the heating system, displace steam take-offs on a steam cogeneration turbine and, thereby, generate additional electric power on a steam binary cogeneration turbine CCGT-CHP.

The essence of the claimed invention lies in the fact that in the method of operation of a binary combined cycle gas-fired power plant, the exhaust gases after a gas turbine installation are supplied to a recovery boiler, the steam generated by the recovery boiler is then fed to expand and complete work in a heating steam turbine, part of the steam from which is taken to the upper and lower network heaters for heating network water, the rest of the steam is sent to a condenser, from which condensate is pumped to a waste heat boiler by a condensate pump p, the flue gas after the recovery boiler is heated up the chemically cleaned water to feed the heating system in a gas-water heater, the flue gas after which additional heating of the mains water is carried out in the gas network heater installed separately from the recovery boiler after the upper network heater, while reducing the steam flow through the reduction-cooling unit (ROW), which is used only for directing reduced steam to the de-aerator of the heating system feed in order to deaerate the chemically purified makeup water eti and increase in steam flow pass the heating part of the steam turbine and also reduce steamlead network heaters to pass and increase the vapor in the "tail" of the low pressure steam turbine cogeneration cylinder.

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 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 flow rate through the reduction and cooling unit (ROW ) to heat 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 chemical heater ennoy makeup water heating system, instead of the established steam heater and through the preheater discharge power upper and lower pair of network preheater and heat recovery of flue gas after the gas-heater demineralized makeup water heating system in gazosetevom preheater. As a result of the implementation of the proposed method, the total pass of steam to the condenser of a cogeneration steam turbine increases and its electric power increases.

The invention is illustrated using the drawing, 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 (GTTH);

20 - cooler make-up water heating system;

21 - cooler vapor (OV) DPTS;

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;

44 - flue gas duct after GPHOV 19;

45 - gas network heater (GSP).

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 the 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 waste heat boiler 4, pipelines of chemically purified make-up water of a heating network 30 with a chemical workshop 18 and a de-aerator of 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 feed pipe of a heating network 35 with a feed water cooler of a heat network 20 and GPHOV 19, and also connected by a feed pipe of a main condensate 28 with a raw condensate feed water heater (PVS-1) 23 and a decontamination unit KU 10;

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; network heater lower 16, network heater upper 15, connected by pipelines of the heat network with a network pump 43, gas network heater (GSP) 45 and a heat consumer 17, as well as connected by pipelines for steam extraction with a heating steam turbine 2;

a gas network heater (GSP) 45, connected by a flue gas duct after GPHOV 44 with a gas-water heater of chemically purified water (GPHOV) 19, pipelines of a heating network with a network heater upper 15, a network heater lower 16, with a network pump 43 and with a heat consumer 17.

The proposed method of operation of a binary CCGT-CHP is as follows.

GTU 1 drives the electric generator 40, which generates electricity. The combustion products after the gas turbine fall into the waste heat boiler 4 and, through the use of the heat of the combustion products of the fuel, generate a steam stream in it, the steam is sent to a heating steam turbine 2, which drives the electric generator 41, which generates electricity. The cogeneration steam turbine 2 has steam withdrawals through pipelines to the network heater upper 15 and 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 condenser 3 is pumped to the boiler using a condensate pump 24 waste disposer 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 flue gases from the exhaust gas duct of the recovery boiler 4 are directed to the gas-water heater of the chemically purified make-up water of the heating network 19. At the same time, the minimum permissible temperature of the exhaust gases after the recovery boiler is used when burning gaseous fuel in the combustion chamber of a gas turbine unit 1, based on the conditions 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 the gas-water heater (GPHOV) 19 and in the gas network heater (GSP) 45.

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 cogeneration steam turbine 2. Steam through the ROW 9 assembly is sent only to the heating system deaerator (DPTS) 11 to deaerate the chemically cleaned heating network water. By adjusting the position of the rotary control diaphragm of the cogeneration steam turbine 2, the steam extraction is reduced, thereby lowering the temperature of the supply water after the network heater upper 15 and the network heater lower 16. In this case, the heat recovery steam extraction from the steam turbine 2 is partially displaced. The displaced steam from the cogeneration take-offs of the steam turbine is sent to the condenser 3. The displaced steam flows from the DOC and cogeneration take-offs lead to an additional increase in the electric power of the cogeneration steam turbine 2. The condensate from the condenser 3 is pumped to the recovery boiler using a condensate pump 24.

As an example, let us consider the operation method of a binary CCPP-CHP based on a T-56 / 70-6.8 cogeneration steam turbine for the city of Novorossiysk. The table shows the results of the calculation of the thermal scheme of a CCGT-CHP plant with heating of additional water for replenishing the heating system with steam from ROW in steam-water PHOV and flue gases of KU in GPKHOV.

In the winter heating period, the flue gases after the CHP heat the cleaned water in the GPHOV before the DPTS, and in the summer, the flue gas stream, after heating the cleaned water in the GPHOV, is additionally used to heat the mains water in the SHG after the lower network heater (SPN).

Table 1 presents the calculation results of the thermal scheme of CCPP-CHP with GPHOV for the city of Novorossiysk at maximum winter and mid-winter modes; table 2 - in the summer mode, with a variation in the temperature of the exhaust gases after the SHG in the range of 80 ÷ 100 ° C.

As you can see, in the winter, the transition to gas heating of make-up water can reduce the steam flow through the DOC by 1.9-2.85 kg / s. This leads to an increase in the electric power of vocational schools by 1.2-1.35 MW.

In the summer period, when utilizing the heat of the flue gases of the recovery boiler only in GPHOV, the value of the additional electric power of the vocational school is 0.4 MW. A further increase in the utilization of the heat of the exhaust gases after HECP due to a decrease in their temperature after the GSP from 100 to 80 ° C leads to an increase in the generation of additional electric power from 0.84 MW to 1.77 MW. This is accompanied by an almost fourfold increase in the heat exchange surface of the SHG, a decrease in the temperature of the network water after the SPN by 7.7 ° C, and a decrease in the steam consumption for the lower network heater by 2.79 kg / s. The temperature of the network water behind the SHG (equal to the temperature of the direct network water) remains set and constant.

Thus, the proposed technical solution allows you to:

- heating the chemically cleaned make-up water of the heating system in the 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;

- unloading the lower network heater in pairs by reducing the amount of steam taken to the network heaters;

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

Claims (1)

The method of operation of a binary combined cycle gas-fired power plant, characterized in that the exhaust gases after the gas turbine installation enter the recovery boiler, the steam generated by the recovery boiler is then fed to expand and perform work in the heating steam turbine, part of the steam from which is diverted to the upper and lower network heaters for heating the mains water, the rest of the steam is sent to a condenser, the condensate from which is pumped to the recovery boiler by a condensate pump, the flue gases after the boiler are heat recovery water is heated up to heat the heating system in a gas-water heater, the flue gases after which additional heating of the network water is performed in a gas network heater installed separately from the recovery boiler after the upper network heater, while reducing the steam consumption through a reduction and cooling unit (ROW), which is used only to direct the reduced steam to the heating system deaerator in order to deaerate the chemically cleaned heating network water and increase the steam pass into the flow part of the cogeneration steam turbine, and also reduce the selection of steam to the network heaters and increase the passage of steam into the "tail" part of the low-pressure cylinder of the cogeneration steam turbine.

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