RU2766653C1 - Steam turbine cogeneration plant - Google Patents

Abstract

FIELD: thermal power engineering.

SUBSTANCE: invention relates to thermal power engineering and can be used at thermal power plants for steam turbine heating plants (STHP), which use steam jet ejectors. The cogeneration steam turbine plant contains a steam turbine 1 with a turbine condenser 2 connected through a branch pipe, a steam extraction line made in the form of a steam pipeline connected to the general station steam collector 8. Steam to the main ejectors 6, 7 of the turbine and to the ejector 10 of the network water heaters, made of steam jet and connected in parallel to each other, is supplied from the general station steam collector 8 through the corresponding steam pipelines through the corresponding steam pipes. The ejector 10 of the network water heaters has a steam-air mixture compression ratio (SAM) of 2…3, which is less than the SAM compression ratio in the main ejectors 6, 7 of the turbine 25…30. Steam heaters 4 and 5 network water horizontal is supplied through line 17 from the selection of the steam turbine 1 through the appropriate pipe. SAM is cascaded from the network water heater 5 to the network water heater 4 along the line 16 for the removal of the steam-air mixture, and then it is sucked out of the network water heater 4 by the ejector 10 of the network water heaters along the steam-air mixture suction line 11. The steam condensate is cascaded from the condensate collector of the heater 5 of the network water to the condensate collector of the heater 4 of the network water. From the condenser 2 of the turbine, by means of a pump 3, the main condensate (MC) is fed through the coolers of the main ejectors 6, 7 of the turbine along the line 13 of the main condensate (MC). The steam condensate through the respective coolers of the main ejectors 6, 7 of the turbine is discharged into the condenser 2 of the turbine through lines 9 for the removal of steam condensate, and the air from the main ejectors 6, 7 of the turbine is discharged through line 14 into the atmosphere. The ejector 10 of the network water heaters through the cooler is connected to the line 13 of the main condensate behind the main ejectors 6, 7 of the turbine, and the condensate of its steam is supplied through the line 12 of the steam condensate outlet to the condensate collector of the first heater 4 of the network water, and from it the steam condensate of the ejector 10 of the network water heaters and steam condensate from the condensate collector of the first heating water heater 4 is fed into the main condensate line 13 after the ejector 10 of heating water heaters.

EFFECT: reduction of heat consumption for own needs of the heating plant and increase in the reliability of the operation of the air suction circuit from the network water heaters.

1 cl, 1 dwg

Description

The invention relates to thermal power engineering and can be used at thermal power plants (TPP) for steam turbine cogeneration plants (STP), which use steam jet ejectors.

At present, in most of the operating heat-and-power plants, air is sucked from the network water heaters into the condenser. In cogeneration turbines that have worked for a long time, there are significant air suctions into the vacuum system, which, in addition to the condenser, includes network water heaters and other elements of the thermal circuit. To improve the efficiency of such turbines (turbine units), it is advisable to separate the vacuum system with the organization of separate air suction from the turbine condenser and heating system water.

Known thermal power plant, which contains a steam boiler connected by a live steam pipeline with a heating turbine, the condenser of which is connected by a steam outlet pipeline to the main steam jet ejector, equipped with an ejector exhaust steam cooler. The exhaust steam cooler of the turbine ejector is included in the gas pipeline in front of the boiler burners with the possibility of cooling it with the supplied gas (RU2572679).

A cogeneration turbine plant is known, which contains a cogeneration turbine with steam extractions connected to regenerative and network heaters, a condenser, a pipeline of the main condensate of the turbine with a steam cooler of the turbine seals and low-pressure regenerative heaters, a cooler of the main steam jet ejectors, a deaerator for make-up water of a heating network with connected to it by pipelines of source water, heating agent, deaerated make-up water of the heating network. The cooler of the main steam jet ejectors is connected through the cooling medium to the heating agent pipeline before the make-up water deaerator of the heating network (RU 2580849).

Known cogeneration turbine plant containing a cogeneration turbine with steam extractions connected to regenerative and network heaters, a condenser connected to it by the main steam jet ejector, the pipeline of the main condensate of the turbine with regenerative low-pressure heaters included in it, a steam cooler for turbine seals, a deaerator for make-up water of a heating network with pipelines of source water, heating agent, deaerated make-up water of the heating network connected to it, the pipeline of the exhaust steam of the main steam jet ejector is connected to the heating agent branch pipe of the make-up water deaerator of the heating network, and the steam cooler of the turbine seals is connected to the cooling medium in the source water pipeline before the make-up deaerator water heating network.

The use of source water in front of the deaerator (RU2572679) or heating water in front of the make-up water deaerator (RU 2580849, RU 2621437) is not satisfactory if a steam jet ejector is installed in the network water heating circuit of a cogeneration plant due to high temperatures of heat carriers or practical (economic) inexpediency.

Known steam turbine cogeneration plant (PTU) containing a steam turbine with a condenser, heating water heaters, the main steam jet ejectors that suck off the steam-air mixture from the condenser, the ejector of heating water heaters that suck off the steam-air mixture from the heaters of heating water, with a working steam pipeline from the steam equalization line of deaerators or common station collector, connected by cooling water to the return network water line with drainage from the ejector coolers to the condenser (Steam turbine T-180/210-130-1, T-180/210-130-2. Operating instructions No. 1570001-IE 1981, 158 pp. LMZ).

In well-known PTUs, the main steam jet ejector is used as an ejector for network heaters.

Closest to the proposed one is a steam turbine heating plant containing a steam turbine with a condenser, main ejectors sucking the steam-air mixture from the condenser and connected in parallel to each other, network water heaters connected in series to each other and connected to the ejector of the network water heaters, sucking the steam-air mixture from network water heaters, a power steam collector connected via a steam pipeline to the main ejectors and the network water heaters ejector, made by steam jets, while the network water heaters ejector is connected via cooling water to the return network water line with drainage from the ejector coolers to the condenser, as an ejector heating network water heaters, a steam-jet ejector with a lower degree of compression of the steam-air mixture (ε=2.5…3.0) was installed in comparison with the main steam-jet ejectors of the turbine (ε=30…40). This analog is taken as a prototype. (Steam turbine T-100-130. Operating instructions. 1960, 95 p. UTZ).

The common disadvantages of the analogue steam turbine T-180/210-130-1, T-180/210-130-2 and the prototype steam turbine T-100-130 are reduced efficiency and reliability associated with connecting the ejector of heating water heaters to the cooling water into the return network water line. This is due to the displacement of the lower heating extraction in the two-stage mode of heating network water due to an increase in the temperature of the return network water heated in the coolers of the ejector of the network water heaters. In addition, in the known device, the drainage of the working steam of the ejector to the condenser is realized, which leads to the loss of heat of this steam with the circulating water. In addition, the suction of non-condensable gases from the network water heaters using the network water heater ejector with the inclusion of the ejector coolers in the return network water line is not very reliable due to a possible increase in the temperature of the return network water, for example, when switching from a schedule of 50/150 ° C to schedule 70/150°C, which can lead to the transition of the ejector to the pre-limiting mode of operation or to the failure of the ejector with a complete loss of performance.

The technical problem of steam turbines that have been in serial operation for decades is the reduced reliability of the operation of the air suction circuit from the network water heaters and the increased heat consumption for the auxiliary needs of the steam turbine cogeneration plant (STP).

The technical result achieved by the claimed invention is to reduce the heat consumption for the own needs of the heating plant and increase the reliability of the operation of the air exhaust circuit from the network water heaters.

To solve the technical problem, a steam turbine heat and power plant (STP) is proposed, containing a steam turbine hermetically connected by means of a branch pipe to the turbine condenser, which has a tap for connecting to the main condensate discharge line (OC) leaving the turbine condenser, the steam turbine is equipped with a steam pipeline that is hermetically connected to steam extraction line connected to the general plant steam collector, the outlet of which is hermetically connected by the corresponding steam pipelines through the steam nozzles to the main ejectors of the turbine and the ejector of the network water heaters made by steam jets, the main ejectors of the turbine are connected to the steam pipelines in parallel to each other, each of the main ejectors of the turbine through the corresponding the coolers are hermetically connected to the corresponding lines for the removal of steam condensate to the turbine condenser, and through branch pipes of the steam-air mixture (SVA) it is hermetically connected to the corresponding lines for suction of the steam-air mixture from the condenser. rbin, the main condensate discharge line is equipped with a pump connected after the turbine condenser, and after the pump, the main turbine ejectors are connected to the main condensate discharge line, the ejector of the network water heaters through the steam-air mixture pipe is connected to the steam-air mixture suction line from the network water heaters, which are included in the line network water and are connected in series with the possibility of connection with the steam extraction line to the lower and upper heaters of the network water, while the ejector of the heating water heaters has a vapor-air mixture compression ratio (SVA) less than the steam-air mixture compression ratio (SVA) in the main turbine ejectors. The claimed PTU differs in that the ejector of the heating water heaters is connected to the line of the main condensate (OK) behind the main ejectors of the turbine, the ejector of the heating water heaters through the cooler is connected to the steam condensate outlet line connected to the condensate collector of the first heating water heater, communicated with the condensate collector of the second heating network water, the condensate collector of the first network water heater is hermetically connected to the steam condensate discharge line, which is connected to the main condensate line (MC) after the ejector of the network water heaters.

In the inventive PTU, the second network water heater is equipped with a vapor-air mixture outlet to the first network water heater, the condensate collector of the second network water heater is equipped with a steam condensate outlet to the condensate collector of the first network water heater. The main ejectors of the turbine and the ejector of the network water heaters are equipped with branch pipes for venting air into the atmosphere.

Connections and connections in the main condensate line, PVA suction lines, steam condensate discharge lines, made in the form of pipelines formed by connecting metal pipes, are made by inserting the corresponding nozzles of the ejectors, nozzles of the condensate collector of the first heating water heater, bends with the formation of a permanent connection, for example, by welding , or a detachable connection, such as a flange connection. The production of lines connecting all parts of the PTU into a single device is carried out by known methods using known materials and equipment. All structural elements implemented in the claimed device of the scheme for connecting the structural parts of the STU (steam turbine, steam jet ejectors, heaters of network water in the form of horizontal heat exchangers, a pump that pumps the main condensate, pipelines and valves) are devices and devices known in science and technology, which are connected to each other by welding or screwing or twisting, forming a single structure of a steam turbine cogeneration plant (STP).

Comparison of the claimed invention with the prototype shows that the claimed PTU differs from the well-known, selected as a prototype, by connecting the network water heater ejector to the main condensate line leaving the turbine condenser, while the connection is made behind the main turbine ejectors, while according to the prototype such connection is made to the return water line. When this removal (drainage) of the condensate steam of the ejector of the network water heaters is made in the condensate collector of the first heating water heater, and not in the turbine condenser, as provided in the prototype. Also, the condensate drain line from the condensate collector of the first network water heater, unlike the prototype, is connected to the main condensate line after the ejector of the network water heaters. The above differences of the claimed invention allow us to conclude that it meets the criterion of "novelty".

The totality of the proposed features of PTU allows to provide a new technical result.

The causal relationship between the claimed set of essential features of the PTU and the achieved technical result is that the inclusion of the ejector of the network water heaters through the cooler (cooling water pipe) into the main condensate line leaving the turbine condenser, immediately after the main turbine ejectors, allows to increase the output electric power by the steam turbine, since the heated condensate displaces the lowest potential steam extraction from the steam turbine to the low-pressure heaters (LPH-1), while the steam flow rates to the lower and upper heating extractions to the network water heaters remain unchanged. In addition, the removal (drainage) of the steam condensate from the ejector of the network water heaters is carried out to the condensate collector of the first network water heater, which makes it possible to exclude heat losses from this drainage with circulating water in the turbine condenser. The inclusion of the ejector of the network water heaters through its cooler into the main condensate line makes it possible to increase the reliability of the air suction circuit from the network water heaters, since the temperature of the main condensate cannot be higher than 55 ° C (the pressure in the condenser of the heating turbine should not exceed 12 kPa, which corresponds to the saturation t _n \u003d 50 ° C; water heating in the main turbine ejector is no more than Δt \u003d 5 ° C; on the contrary, the temperature of the return network water can reach 70 ° C), which allows you to maintain the length of the operating characteristic of the ejector of the network water heaters unchanged in various modes work of vocational schools.

The claimed PTU is illustrated by the following example of a specific implementation. On FIG. 1 schematically shows the inventive steam turbine heating plant (STP). On FIG. 1 adopted the following designations:

1 - steam turbine of a heat and power steam turbine plant (PTU);

2 - turbine condenser;

3 - pump;

4, 5 - heaters of network water horizontal PSG-1 and PSG-2;

6, 7 - the main ejectors of the turbine for suction of the steam-air mixture (SVA) from the turbine condenser;

8 - general station steam collector for ejectors;

9 - lines for the removal of steam condensate from the main ejectors of the turbine to the turbine condenser;

10 - ejector of network water heaters;

11 - suction line of steam-air mixture from network water heaters;

12 - line for the removal of steam condensate from the ejector of the network water heaters.

13 - main condensate line;

14 - removal of air (steam-air mixture) of their ejectors into the atmosphere;

15 - suction line of the steam-air mixture from the turbine condenser to the main turbine ejectors;

16 - line for removing the steam-air mixture from PSG-2 to PSG-1;

17 - steam supply line to network water heaters.

Implementation of the invention

The inventive heating steam turbine plant (PTU) contains a steam turbine 1 with a turbine condenser 2 connected through a pipe (not shown), a steam extraction line made in the form of a steam pipeline connected to a general station steam collector 8. Ejectors 6, 7, 10 are made of steam jet. Steam to the main ejectors 6, 7 of the turbine and to the ejector 10 of the network water heaters, connected in parallel to each other, is supplied from the general station steam collector 8 through the corresponding steam pipelines. The ejectors 6, 7 and 10 are independently hermetically connected to the general station steam collector 8 through the corresponding steam pipes. In the proposed PTU, commercially available ejectors of the EP-3-2 brands, acceptable for these purposes, can be used, and the ejector 10 of the network water heaters has a PVA compression ratio of 2 ... 3, which is less than the PVA compression ratio in the main ejectors 6, 7 of the turbine - 25 …thirty. This provides a reduction in steam flow to the ejector 10 of the network water heaters in comparison with the main ejectors 6, 7 of the turbine. Heaters 4 and 5 network water horizontal (PSG-1) and (PSG-2), respectively, are heat exchangers known in science and technology, steam to which is supplied through line 17 from the selections of the steam turbine 1 through the corresponding pipe. The steam-air mixture (PVA) is cascaded from the network water heater 5 (PSG-2) (upper) to the network water heater 4 (PSG-1) (lower) along the line 16 for removing the steam-air mixture from PSG-2 to PSG-1, and then is sucked out of the network water heater 4 (PSG-1) by the ejector 10 of the network water heaters through the steam-air mixture suction line 11. The steam condensate is cascaded from the condensate collector of the network water heater 5 (PSG-2) to the condensate collector 4 of the network water heater (PSG-1), the steam condensate is drained by gravity from the upper PSG-2 to the lower one at PSG-1. From the condenser 2 of the turbine, by means of a pump 3, the main condensate (OK) is fed through the coolers of the main ejectors 6, 7 of the turbine along the line 13 of the main condensate (OK). The steam condensate through the respective coolers of the main ejectors 6, 7 of the turbine is discharged into the condenser 2 of the turbine through lines 9 for the removal of steam condensate, and the air from the main ejectors 6, 7 of the turbine is discharged through line 14 into the atmosphere. The ejector 10 of the network water heaters through the cooler is connected to the line 13 of the main condensate behind the main ejectors 6, 7 of the turbine, and the condensate of its steam is supplied through the line 12 of the steam condensate removal to the condensate trap of the first heater 4 of the network water (PSG-1), and from it the steam condensate of the ejector 10 of the network water heaters and the steam condensate from the condensate collector of the first (lower) heater 4 of the network water (PSG-1) is fed into the main condensate line 13 after the ejector 10 of the network water heaters.

The work of the proposed cogeneration steam turbine plant is carried out as follows. The steam, having passed the steam turbine 1, enters the condenser 2 of the turbine, which is connected through a branch pipe. From the condenser 2 of the turbine, the steam condensate is fed through the pump 3 to the line 13 of the main condensate, in which the coolers of the main ejectors 6 and 7 of the turbine are connected in series, and after them the ejector 10 of the network water heaters, the steam to which is supplied through the steam pipeline from the general station steam collector 8 connected to steam extraction of the turbine 1, and the steam condensate from the main ejectors 6, 7 of the turbine is sent to the condenser 2 of the turbine through the lines 9 for the removal of steam condensate. From the ejector 10 of the network water heaters, the steam condensate is discharged through line 12 from the ejector 10 of the network water heaters to the network water heater 4 (PSG-1). The main ejectors 6, 7 of the turbine, creating a vacuum, suck off the steam-air mixture from the condenser 2 of the turbine through line 15, and the ejector 10 of the network water heaters, due to the vacuum created, sucks the PVA through line 11 from the heater 4 of the network water (PSG-1). Steam from the steam turbine 1 is also sent through line 17 to the heaters 4 and 5 of network water (PSG-1 and PSG-2), where it heats the network water. The steam condensate formed in the network water heaters 4.5 in a cascade is drained from the condensate collector of the network water heater 5 (PSG-2) into the condensate collector of the network water heater 4 (PSG-1), and then by pump 3 the steam condensate from the condensate collector of the network water heater 4 and the steam condensate of the ejector 10 of the network water heaters is jointly discharged into the line 13 of the main condensate after the ejector 10 of the network water heaters. The steam-air mixture in the network water heaters 4 and 5 is cascaded from the network water heater 5 (PSG-2) to the network water heater 4 (PSG-1) via line 16.

The inclusion of the ejector 10 of the network water heaters in the line 13 of the main turbine condensate behind the main ejectors 6, 7 of the turbine allows you to keep the ejector 10 of the network water heaters in any operating mode of the turbine. If the ejector 10 network water heaters were included in the return network water line before PSG-1, as in the prototype, then when the temperature of the return network water rises to 70 ° C, the characteristic of the ejector 10 network water heaters would switch to a pre-limiting mode with a sharp increase in pressure suction in the ejector of 10 network water heaters. From the ejector 10 of the network water heater, the working steam condensate is discharged to the condensate collector of the first network water heater 4 (PSG-1) through line 12, and then the steam condensate of the ejector 10 of the network water heater and the network water heaters 4.5 is discharged into line 13 of the main condensate after the ejector 10 network water heaters, which makes it possible to exclude heat losses in comparison with the removal of ejector steam condensate to the turbine condenser 2.

The claimed PTU provides cost-effectiveness and efficiency when used at thermal power plants with cogeneration turbines by reducing heat consumption for own needs of a steam turbine cogeneration plant and increasing the reliability of the air exhaust circuit from network water heaters.

Claims (1)

A steam turbine cogeneration plant containing a steam turbine hermetically connected by means of a branch pipe to the turbine condenser having a branch for connection to the main condensate discharge line in the form of a pipeline, the steam turbine is equipped with a steam pipeline, which is hermetically connected by a steam extraction line to the general station steam collector, the outlet of which is through the corresponding steam pipelines through the steam branch pipes are hermetically connected to the main ejectors of the turbine and the ejector of the network water heaters made by steam jets, the main ejectors of the turbine are connected to the steam pipelines in parallel to each other, each of the main ejectors of the turbine is hermetically connected through the corresponding coolers to its own steam condensate discharge line to the turbine condenser, and through the corresponding branch pipes of the steam-air mixture are hermetically connected to their own line for suction of the steam-air mixture from the turbine condenser, the main condensate discharge line is equipped with a pump connected after the condensate turbine head, the main ejectors of the turbine are connected in series to the main condensate discharge line after the pump, the ejector of the heating water heaters through the branch pipe of the steam-air mixture is connected to the suction line of the steam-air mixture from the heating water heaters, which are included in the heating water line and connected to each other in series with the possibility of connection to the steam extraction line to the lower and upper network water heaters through steam pipelines, while the network water heater ejector has a steam-air mixture compression ratio less than the steam-air mixture compression ratio in the main turbine ejectors, characterized in that the network water heaters ejector is connected to the main condensate line behind the main ejectors of the turbine, the ejector of the heating water heaters through the cooler is connected to the steam condensate discharge line, hermetically connected to the condensate collector of the first heating water heater, which is connected by means of a drain to the condensate collector of the second of the network water heater, the condensate collector of the first network water heater is hermetically connected to the steam condensate discharge line, which is connected to the main condensate line after the network water heater ejector.

Images