CN211854139U

CN211854139U - Heating system based on low-pressure optical axis technology of steam turbine

Info

Publication number: CN211854139U
Application number: CN201922256275.2U
Authority: CN
Inventors: 王建勋; 白旭东; 郝亚珍; 秦万阔; 张竞飞; 张贺
Original assignee: Beijing Guodian Blue Sky Energy Saving Technology Development Co ltd
Current assignee: Guoneng Longyuan Lantian Energy Saving Technology Co.,Ltd.
Priority date: 2019-12-16
Filing date: 2019-12-16
Publication date: 2020-11-03
Anticipated expiration: 2029-12-16

Abstract

The utility model relates to a heating system based on steam turbine low pressure optical axis technique for solve current optical axis heating technique and do not have the shortcoming of heat, electrolytic coupling ability and provide the feasibility. The heat supply system comprises a steam turbine, a peak heater, a waste steam heat exchanger and a back pressure steam turbine, wherein the main steam turbine comprises a high pressure cylinder, a middle pressure cylinder and a low pressure cylinder, and an optical axis rotor is arranged in the low pressure cylinder; the steam outlet of the intermediate pressure cylinder can be selectively communicated with the steam inlet of the back pressure steam turbine and the steam inlet of the peak heater in an on-off manner and with adjustable flow; the steam outlet of the back pressure steam turbine can be selectively communicated with the steam inlet of the dead steam heat exchanger and the steam inlet of the low pressure cylinder in an on-off and flow-adjustable mode.

Description

Heating system based on low-pressure optical axis technology of steam turbine

Technical Field

The utility model relates to a generating set technical field especially relates to heating system based on steam turbine low pressure optical axis technique.

Background

In recent years, the national energy structure changes, new energy is rapidly developed, the orderly planning and development of the power industry are very important, the urbanization construction process is continuously promoted, rural population is continuously shifted to cities and towns, the urban residential area is more and more, the heat supply demand is more and more, the environmental protection is continuously improved, the energy conservation and emission reduction situation is very severe, how to effectively exert the capability of the traditional thermal power generating unit, the heat supply potential of the coal-fired heat supply unit in service is deeply excavated, the urban centralized heat supply degree is improved, the energy consumption is reduced, the urban heat supply demand is met, the low-pressure cylinder optical axis heat supply technology is an important technology capable of realizing energy conservation and emission reduction, the waste heat of the steam turbine generator set is recovered to the maximum.

The low pressure cylinder optical axis heat supply technology is to renew the original electric butterfly valve on the middle and low pressure communicating pipe, so that the low pressure cylinder does not enter steam, and the main steam enters the high and medium pressure cylinder to do work through the high pressure main steam valve and the high pressure regulating valve. The exhaust steam of the intermediate pressure cylinder enters the peak heater for heat supply through a heat supply steam extraction pipeline. The low pressure rotor is demolishd, changes into an optical axis rotor (not taking the blade), takes out low pressure baffle cover and baffle, remains low pressure both ends vapor seal, and the total weight of optical axis rotor equals original low pressure jar rotor weight, and the low pressure jar does not do work at this stage, and high-medium pressure rotor and generator are connected to the low pressure rotor, only plays the effect of transmission moment of torsion. In the heat supply period, the unit operates by adopting an optical axis, namely a back pressure machine operates, most of the exhaust steam of the intermediate pressure cylinder enters the peak heater through the heat supply steam extraction pipeline to heat the circulating water of the heat supply network after being boosted by the circulating water pump of the heat supply network to supply heat to an external network, and a small part (5-15t/h) of the exhaust steam of the intermediate pressure cylinder enters the low pressure cylinder through the cooling steam pipeline after being subjected to temperature and pressure reduction to take away the friction blast heat generated by the optical axis rotor (without blades) of the low pressure cylinder and the steam (or air) in the low pressure cylinder, so that the exhaust steam cooling loss of the low pressure cylinder. In the non-heat supply period, the low-pressure cylinder adopts the low-pressure rotor (with blades) of the original unit, the exhaust steam of the intermediate pressure cylinder enters the low-pressure cylinder to do work, and the exhaust steam parameters are restored to normal levels, namely, the steam turbine is restored to operate in a pure condensing mode. The low-pressure cylinder optical axis heat supply technology can recover the original heat of exhaust steam entering the condenser from the low-pressure cylinder, and the heat is replaced by an optical axis rotor (without blades), and the steam has no enthalpy drop, so that as much heat as possible can be used for heat supply. However, the optical axis operation is adopted in the low-pressure cylinder optical axis heat supply technology in the heat supply period in winter, namely, the back pressure machine operates, the low-pressure cylinder optical axis heat supply technology generally operates in a mode of fixing power by heat, the limitation of the inherent characteristics of a unit is met, the heat supply load changes slowly along with time, the unit basically does not have the power peak regulation capacity for ensuring the heat supply quality, particularly in the initial and final stages of heat supply and the secondary cold period of heat supply, the heat supply load demand is small, the working condition with large power generation load demand cannot be met, and the operation mode; moreover, the drainage of a peak heater in the heat supply of the optical axis of the low-pressure cylinder directly enters the low-pressure heater or the deaerator through a heat network drainage pump, the steam entering the condenser only has a small part (5-15t/h) of steam for cooling the low-pressure cylinder, and the condensate pump can only operate in a low-frequency mode of opening a recirculated water valve, so that the safe operation of the condensate pump and the shaft seal cooler is seriously influenced.

SUMMERY OF THE UTILITY MODEL

Technical problem to be solved

The utility model aims to provide feasibility for solving the shortcoming that the existing optical axis heat supply technology does not have heat and electrolytic coupling capacity.

(II) technical scheme

In order to achieve the above object, the utility model discloses a main technical scheme include:

the utility model provides a heating system based on the low-pressure optical axis technology of a steam turbine, which comprises a steam turbine, a peak heater, a waste steam heat exchanger and a back pressure steam turbine; the steam turbine comprises a high-pressure cylinder, a medium-pressure cylinder and a low-pressure cylinder which is transformed into an optical axis; the steam outlet of the intermediate pressure cylinder can be selectively communicated with the steam inlet of the back pressure steam turbine and the steam inlet of the peak heater in an on-off manner and with adjustable flow; the steam outlet of the back pressure steam turbine can be selectively communicated with the steam inlet of the low pressure cylinder and the steam side inlet of the exhaust steam heat exchanger in an on-off and flow-adjustable mode.

According to the utility model, the steam outlet of the intermediate pressure cylinder is communicated with the steam inlet of the peak heater and the steam inlet of the back pressure turbine through pipelines, the pipelines comprise a shared pipeline segment, a first branch pipeline segment and a second branch pipeline segment, the first branch pipeline segment is connected between the peak heater and the shared pipeline segment, and the second branch pipeline segment is connected between the back pressure turbine and the shared pipeline segment; an extraction check valve, an extraction quick closing valve, an extraction electric valve and an orifice plate flowmeter are sequentially arranged on the common pipeline section along the direction of the intermediate pressure cylinder pointing to the peak heater; the first branch pipeline section is provided with a peak heater steam inlet regulating valve; and a back pressure type steam turbine steam inlet regulating valve is arranged on the second branch pipeline section.

According to the utility model discloses, alternative break-make ground intercommunication between the steam extraction mouth of intermediate pressure jar and the steam inlet of low pressure jar to be equipped with the pressure reducer that reduces temperature between the two.

According to the utility model, the steam outlet of the low pressure cylinder is communicated with the steam inlet of the condenser through a pipeline, and the pipeline is provided with the steam inlet electric valve of the condenser; the steam outlet of the intermediate pressure cylinder is selectively communicated with the steam inlet of the low pressure cylinder in a switching mode through a first pipeline and a second pipeline which are connected in parallel; a hydraulic shutoff valve is arranged on the first pipeline; a temperature and pressure reduction device, a flow meter of a cylinder hole plate from the middle pressure cylinder to the low pressure cylinder and a regulating valve of the cylinder from the middle pressure cylinder to the low pressure cylinder are arranged on the second pipeline along the direction from the middle pressure cylinder to the low pressure cylinder; the desuperheating water inlet of the desuperheating pressure reducer is connected with a condensed water cooling water pipeline, and a condensed water cooling water regulating valve is arranged on a pipeline connected with the desuperheating pressure reducer and the condensed water cooling water pipeline; the steam outlet of the back pressure turbine is communicated with the steam inlet of the low pressure cylinder through a pipeline, and the steam exhaust of the back pressure turbine is arranged on the pipeline to the low pressure cylinder hole plate flowmeter and the steam exhaust of the back pressure turbine to the low pressure cylinder regulating valve along the direction from the steam outlet of the back pressure turbine to the steam inlet of the low pressure cylinder; the steam outlet of the back pressure steam turbine is communicated with the steam side inlet of the exhaust steam heat exchanger through a pipeline, and the pipeline is provided with an electric steam inlet valve of the exhaust steam heat exchanger.

According to the utility model discloses, the steam side export of peak heater and the upper portion of condenser 8 and the equal selective break-make ground of condenser well intercommunication, the steam side export and the condenser well intercommunication of exhaust steam heat exchanger.

According to the utility model, the steam side outlet of the peak heater is communicated with the upper part of the condenser 8 through a pipeline, and the pipeline is provided with a regulating valve for draining water from the peak heater to the condenser; the steam side outlet of the peak heater is communicated with the condenser well through a pipeline, and an electric valve for draining water from the peak heater to the condenser well is arranged on the pipeline; a water side inlet of the peak heater is selectively communicated with a heat supply network circulating water return pipeline and a heat supply network circulating water outlet pipeline in a switching mode; and a water side outlet of the peak heater is communicated with a circulating water supply pipeline of the heat supply network.

According to the utility model discloses, the water side entry and the selectable break-make of big quick-witted circulating water return water pipeline of condenser communicate, and the water side export of condenser communicates with the selectable break-make of big quick-witted circulating water outlet pipe way, and the water side entry and the selectable break-make of condenser well and heat supply network circulating water return water pipeline of exhaust steam heat exchanger communicate, and the water side export and the condensate system of exhaust steam heat exchanger and the selectable break-make of heat supply network circulating water outlet pipe way communicate.

According to the utility model, the water side inlet of the condenser is communicated with the circulating water return pipeline of the main engine through a pipeline, and the pipeline is provided with a circulating water return electric valve of the main engine; the water side outlet of the condenser is communicated with a circulating water outlet pipeline of the large engine through a pipeline, and the pipeline is provided with a circulating water outlet electric valve of the large engine; the water side inlet of the exhaust steam heat exchanger is communicated with a water well of a condenser through a pipeline, and a condensate pump and an electric valve for the condensate water inlet of the exhaust steam heat exchanger are arranged on the pipeline; a water side inlet of the exhaust steam heat exchanger is communicated with a circulating water return pipeline of a heat supply network through a pipeline, and the pipeline is provided with an electric valve for circulating water return of the heat supply network of the exhaust steam heat exchanger; the water side outlet of the exhaust steam heat exchanger is communicated with a condensed water system through a pipeline, and the pipeline is provided with an electric valve for discharging condensed water of the exhaust steam heat exchanger; the water side outlet of the exhaust steam heat exchanger is communicated with a circulating water outlet pipeline of the heat supply network through a pipeline, and the pipeline is provided with an electric valve for the circulating water outlet of the heat supply network of the exhaust steam heat exchanger.

According to the utility model discloses, be equipped with exhaust steam heat exchanger water side bypass in exhaust steam heat exchanger department, the pipeline that feeds through water side entry and water side export is parallelly connected in exhaust steam heat exchanger water side bypass and the exhaust steam heat exchanger, is equipped with exhaust steam heat exchanger bypass electric valve on exhaust steam heat exchanger water side bypass, and the entry of exhaust steam heat exchanger water side bypass is located the upper reaches of exhaust steam heat exchanger condensate water inflow electric valve, and the export of exhaust steam heat exchanger water side bypass is located exhaust steam heat exchanger condensate water outflow electric valve's low reaches.

According to the utility model, the device also comprises energy supply equipment; the back pressure turbine is connected with energy supply equipment, and the energy supply equipment is an additional generator, a heat supply network circulating pump, a water supply pump or an induced draft fan.

(III) advantageous effects

The utility model has the advantages that:

the utility model discloses a heating system can satisfy current optical axis heating technology heat supply, can avoid optical axis heating technology again "with the inherent characteristic restriction of heat fixed electricity", it is hot, the poor shortcoming of electrolytic coupling ability, especially at heat supply first and last stage and inferior cold period, the heat supply load demand is little, under the big operating mode of power generation load demand, utilize this heating system, can increase main steam flow operation, detach the intermediate pressure jar steam extraction that is used for the heat supply, the intermediate pressure jar steam extraction that exceeds gets into back pressure steam turbine and does work, little in order to satisfy the heat supply load demand, the big operating mode of power generation load demand. The steam flow entering the peak heater and the back pressure turbine can be adjusted according to different heat supply load and power generation load scheduling requirements, and the heat and electrolytic coupling capacity of the unit is fully improved.

The utility model discloses a heating system, the hydrophobic and low pressure jar condensate water that the steam exhaust of hydrophobic, back pressure turbine exhaust steam formed of peak heater wherein finally all converges in the condenser well to the safe operation of big quick-witted condensate pump and bearing seal cooler has been guaranteed.

Drawings

Fig. 1 is a schematic structural view of an embodiment of the heating system of the present invention;

fig. 2-15 are schematic views of different modes of the heating method according to the present invention when applying an embodiment of the heating system according to fig. 1, wherein only conducting paths are shown.

[ reference numerals ]

1: a high pressure cylinder; 2: an intermediate pressure cylinder; 3: a low pressure cylinder; 4: a back pressure turbine; 5: a generator; 6: an additional generator; 7: a spike heater; 8: a condenser; 9: a condensate pump; 10: a waste steam heat exchanger; 11: a steam extraction check valve; 12: a steam extraction quick closing valve; 13: an electric steam extraction valve; 14: an orifice plate flowmeter; 15: a peak heater steam inlet regulating valve; 16: draining water from the peak heater to a condenser regulating valve; 17: draining water from the peak heater to a water well electric valve of a condenser; 18: a large machine circulating water backwater electric valve; 19: the large machine circulating water outlet electric valve; 20: a vacuum-pumping electric valve; 21: an electric valve for steam inlet of the condenser; 22: the back pressure turbine exhausts steam to a low pressure cylinder regulating valve; 23: the waste steam of the back pressure steam turbine flows to a low-pressure cylinder hole plate flowmeter; 24: a hydraulic shut-off valve; 25: a back pressure turbine steam inlet regulating valve; 26: a temperature and pressure reducer; 27: the condensed water cools the water regulating valve; 28: the intermediate pressure cylinder exhausts steam to the low pressure cylinder regulating valve; 29: the intermediate pressure cylinder exhausts steam to the low pressure cylinder hole plate flowmeter; 30: a steam exhaust heat exchanger to a condenser water well regulating valve; 31: an electric valve for steam inlet of the exhaust steam heat exchanger; 32: a circulating water backwater electric valve of a heat supply network of the exhaust steam heat exchanger; 33: an electric valve for circulating water outlet of a heat supply network of the exhaust steam heat exchanger; 34: an electric valve for the condensed water of the exhaust steam heat exchanger to enter water; 35: an electric valve for discharging condensed water of the exhaust steam heat exchanger; 36: the waste steam heat exchanger bypasses an electric valve.

Detailed Description

For a better understanding of the present invention, reference will now be made in detail to the present invention, examples of which are illustrated in the accompanying drawings.

Referring to fig. 1, the present embodiment provides a heating system based on a low-pressure optical axis technology of a steam turbine, the heating system includes a steam turbine, the steam turbine includes a high-pressure cylinder 1, an intermediate-pressure cylinder 2 and a low-pressure cylinder 3, and an optical axis rotor is installed in the low-pressure cylinder 3. The heating system also comprises a back pressure turbine 4, a generator 5, an additional generator 6, a peak heater 7, a condenser 8, a condensate pump 9 and a waste steam heat exchanger 10.

The steam outlet of the intermediate pressure cylinder 2 is in selective on-off and flow-adjustable communication with the steam inlet of the spike heater 7, and the steam outlet of the intermediate pressure cylinder 2 is in selective on-off and flow-adjustable communication with the steam inlet of the back pressure turbine 4. In detail to the structure in the present embodiment, the exhaust port of the intermediate pressure cylinder 2 is communicated with both the steam inlet of the spike heater 7 and the steam inlet of the back pressure turbine 4 through a pipeline including a common pipeline section, a first branch pipe section connected between the spike heater and the common pipeline section, and a second branch pipe section connected between the back pressure turbine and the common pipeline section. And an extraction check valve 11, an extraction quick closing valve 12, an extraction electric valve 13 and an orifice flowmeter 14 are sequentially arranged on the common pipeline section along the direction of the intermediate pressure cylinder pointing to the peak heater. The first branch pipeline section is provided with a peak heater steam inlet regulating valve 15, and the second branch pipeline section is provided with a back pressure turbine steam inlet regulating valve 25. The steam exhaust port of the intermediate pressure cylinder 2 is selectively communicated with the steam inlet of the peak heater 7 in a switching mode through the steam exhaust check valve 11, the steam exhaust quick closing valve 12, the steam exhaust electric valve 13 and the peak heater steam inlet adjusting valve 15, and the steam exhaust port of the intermediate pressure cylinder 2 is communicated with the steam inlet of the peak heater 7 in a flow-adjustable mode through the peak heater steam inlet adjusting valve 15. The steam exhaust port of the intermediate pressure cylinder 2 is selectively communicated with the steam inlet of the back pressure turbine 4 in an on-off mode through the steam exhaust check valve 11, the steam exhaust quick closing valve 12, the steam exhaust electric valve 13 and the back pressure turbine steam inlet adjusting valve 25, and the steam exhaust port of the intermediate pressure cylinder 2 is communicated with the steam inlet of the back pressure turbine 4 in an adjustable flow mode through the back pressure turbine steam inlet adjusting valve 25.

The steam outlet of the intermediate pressure cylinder 2 is selectively communicated with the steam inlet of the low pressure cylinder 3 through a first pipeline and a second pipeline which are connected in parallel. A hydraulic shut-off valve 24 is arranged on the first pipeline and is used for completely isolating the low-pressure cylinder from the intermediate-pressure cylinder, and the valve is opened when the pure condensation working condition is recovered in the non-heat supply period in summer, and the exhaust steam of the intermediate-pressure cylinder is recovered to directly enter the low-pressure cylinder; on the second pipeline, a temperature-reducing pressure reducer 26, an intermediate cylinder steam exhaust to low pressure cylinder hole plate flowmeter 29 and an intermediate cylinder steam exhaust to low pressure cylinder regulating valve 28 are provided in a direction from the intermediate cylinder 2 to the low pressure cylinder 3. The desuperheating water inlet of the desuperheating pressure reducer 26 is connected to a condensed water cooling water pipe, and a condensed water cooling water regulating valve 27 is provided on a pipe connecting the both.

The steam outlet of the back pressure turbine 4 is in selective on-off and flow-adjustable communication with the steam inlet of the low pressure cylinder 3. In detail, in the structure of the embodiment, the steam outlet of the back pressure turbine 4 is communicated with the steam inlet of the low pressure cylinder 3 through a pipeline, and the back pressure turbine exhaust steam is arranged on the pipeline along the direction from the back pressure turbine 4 to the low pressure cylinder 3 to the low pressure cylinder hole plate flowmeter 23 and the back pressure turbine exhaust steam to the low pressure cylinder regulating valve 22, which realizes that the steam outlet of the back pressure turbine 4 is selectively communicated with the steam inlet of the low pressure cylinder 3 in an on-off and flow-adjustable manner.

The steam outlet of the back pressure turbine 4 is selectively communicated with the steam side inlet of the waste steam heat exchanger 10 in an on-off and flow-adjustable mode. An electric steam inlet valve 31 of the waste steam heat exchanger is arranged on a pipeline connecting a steam outlet of the back pressure steam turbine 4 and a steam side inlet of the waste steam heat exchanger 10, so that the steam outlet and the waste steam heat exchanger can be selectively communicated in an on-off mode and in a flow-adjustable mode.

The back pressure turbine 4 is also connected to an additional generator 6 for supplying energy to the additional generator 6. Of course, in other embodiments, the additional generator 6 may be replaced by a heat supply network circulation pump, a feed water pump, an induced draft fan, and other devices requiring power supply.

The steam outlet of the low pressure cylinder 3 is communicated with the condenser 8 through a pipeline, and a condenser steam inlet electric valve 21 is arranged on the pipeline communicated with the steam outlet of the low pressure cylinder and the condenser 8.

The low pressure cylinder 3 is also connected to a generator 5.

The steam side outlet of the peak heater 7 is selectively communicated with the upper part of the condenser 8 in an on-off and flow-adjustable manner, and a pipeline connected with the peak heater and the condenser 8 is provided with a peak heater drainage and condenser regulating valve 16 so as to realize the selective on-off and flow-adjustable communication.

The steam side outlet of the peak heater 7 is selectively communicated with the water well of the condenser 8 in an on-off mode, and a pipeline for communicating the water well of the condenser 8 with the steam side outlet of the peak heater 7 is provided with a peak heater drainage to condenser water well electric valve 17 so as to achieve the selective on-off communication.

The water inlet of the peak heater 7 is selectively connected to the return line of the circulating water in the heat supply network and the outlet line of the circulating water in the heat supply network (not shown), for example, by valves (not shown).

The water side outlet of the spike heater 7 is connected to the heating network circulating water supply line (not shown).

And a water side inlet of the condenser 8 is selectively communicated with a circulating water return pipeline of the large machine in a switching mode. In detail, in the structure of the embodiment, a large-machine circulating water backwater electric valve 18 is arranged on a pipeline connected with the large-machine circulating water backwater electric valve to realize that the large-machine circulating water backwater electric valve and the large-machine circulating water backwater electric valve can be selectively communicated in a switching mode.

The water side outlet of the condenser 8 is selectively communicated with a circulating water outlet pipeline of the large machine in a switching mode. In detail, in the structure of the embodiment, a pipeline connected with the two is provided with a large machine circulating water outlet electric valve 19 so as to realize the selective on-off communication of the two.

The condenser 8 is also selectively communicated with a vacuum-pumping system. In detail, in the structure of the present embodiment, a vacuum-pumping electric valve 20 is disposed on the pipeline connecting the two, so as to realize the selectable communication between the two.

The water side inlet of the exhaust steam heat exchanger 10 is selectively communicated with the water well of the condenser 8. In detail, in the structure of the embodiment, a condensed water pump 9 and a condensed water inlet electric valve 34 of the exhaust steam heat exchanger are arranged on a pipeline connecting a water side inlet of the exhaust steam heat exchanger 10 and a water well of the condenser 8, so as to realize the selectable communication of the two.

The water side inlet of the exhaust steam heat exchanger 10 is also selectively communicated with a circulating water return pipeline of a heat supply network in a switching mode. In detail, in the structure of the embodiment, a pipeline connecting a water side inlet of the exhaust steam heat exchanger 10 and a circulating water return pipeline of the heat supply network is provided with an exhaust steam heat exchanger circulating water return electric valve 32, so that the exhaust steam heat exchanger and the circulating water return electric valve can be selectively communicated.

The water side outlet of the waste steam heat exchanger 10 is in selective on-off communication with the condensate system. In detail, in the structure of the embodiment, the pipeline connecting the water side outlet of the exhaust steam heat exchanger 10 and the condensate system is provided with an exhaust steam heat exchanger condensate water outlet electric valve 35 to realize the selectable communication of the two.

The water side outlet of the exhaust steam heat exchanger 10 is also selectively communicated with the heat supply network circulating water outlet pipeline connected with the peak heater 7 in an on-off mode. In detail, in the structure of this embodiment, an electric valve 33 for the circulating water outlet of the heat supply network of the exhaust steam heat exchanger is arranged on a pipeline connecting the water side outlet of the exhaust steam heat exchanger 10 and the circulating water outlet pipeline of the heat supply network, so as to realize the selective communication between the water side outlet and the circulating water outlet pipeline of the heat supply network.

In summary, the heat supply network circulating water returning pipeline (not shown in the figure) is directly and selectively communicated with the water side inlet of the peak heater 7 in an on-off mode, and the heat supply network circulating water returning pipeline is selectively communicated with the exhaust steam heat exchanger 10 in an on-off mode, so that water can be selectively supplied to one of the peak heater 7 and the exhaust steam heat exchanger 10 through the heat supply network circulating water returning pipeline.

The steam exhaust heat exchanger 10 is provided with a steam exhaust heat exchanger water side bypass, the steam exhaust heat exchanger water side bypass is connected in parallel with a pipeline which is arranged in the steam exhaust heat exchanger 10 and used for communicating a water side inlet and a water side outlet, and a steam exhaust heat exchanger bypass electric valve 36 is arranged on the steam exhaust heat exchanger water side bypass so as to determine whether the steam exhaust heat exchanger 10 participates in heat exchange in the system. The inlet of the waste steam heat exchanger water side bypass is positioned at the upstream of the waste steam heat exchanger condensed water inlet electric valve 34, and the outlet of the waste steam heat exchanger water side bypass is positioned at the downstream of the waste steam heat exchanger condensed water outlet electric valve.

The steam side outlet of the exhaust steam heat exchanger 10 is selectively communicated with the water well of the condenser 8. In detail, in the structure of the present embodiment, a steam exhaust heat exchanger to condenser water well regulating valve 30 is provided on a pipeline connecting the steam side outlet of the steam exhaust heat exchanger 10 and the water well of the condenser 8.

Based on the above description of the heating system, a heating method implemented by the heating system is described as follows.

In the heat supply period, the steam exhausted by the intermediate pressure cylinder of the steam turbine is divided into at least two branches, the steam exhausted by the intermediate pressure cylinder in the first branch enters the peak heater 7 for heat supply, and the steam exhausted by the intermediate pressure cylinder in the second branch enters the back pressure steam turbine 4 for work. And adjusting the opening degrees of the peak heater steam inlet adjusting valve 15 and the back pressure turbine steam inlet adjusting valve 25 according to the requirements of heat supply load and power generation load, so as to adjust the distribution ratio of the steam exhaust of the first branch intermediate pressure cylinder and the steam exhaust of the second branch intermediate pressure cylinder. Therefore, the thermal and electrolytic coupling capacity of the unit can be fully improved.

In this embodiment, the heating method includes a first heating mode and a second heating mode. On the premise of meeting a certain heat supply load in the initial and final stages of heat supply and the secondary cold stage, the corresponding large machine can produce a certain power generation load, and if the dispatching requirement is the power generation load of the working condition (namely when the power generation requirement is less than or equal to the standard power generation load), the operation mode of 'fixing power by heat' is adopted, and a first heat supply mode is adopted. On the basis of the first heating mode, when the power generation load demand increases, that is, the power generation demand is greater than the standard power generation load, the second heating mode is adopted.

The first heating mode is described as follows.

The exhaust steam of the intermediate pressure cylinder is divided into two branches or three branches.

Referring to fig. 2 and 3, when the medium pressure cylinder exhaust steam is divided into two branches:

the exhaust steam of the intermediate pressure cylinder is divided into a first branch intermediate pressure cylinder exhaust steam and a second branch intermediate pressure cylinder exhaust steam, the first branch intermediate pressure cylinder exhaust steam accounts for the most part of the total exhaust steam of the intermediate pressure cylinder 2, and the exhaust steam amount of the second branch intermediate pressure cylinder is only 5-15 t/h.

The steam extraction check valve 11, the steam extraction quick closing valve 12 and the steam extraction electric valve 13 are opened, and the peak heater steam inlet regulating valve 15 and the back pressure turbine steam inlet regulating valve 25 are adjusted to proper opening degrees. The first branch intermediate pressure cylinder exhaust steam enters the spike heater 7 from the exhaust steam port of the intermediate pressure cylinder 2 through the steam inlet of the spike heater 7.

A valve between the heat supply network circulating water return pipeline and a water side inlet of the peak heater 7 is opened, so that the heat supply network circulating water return water can directly enter the peak heater 7 through the water side inlet of the peak heater 7, the steam discharged by the medium pressure cylinder in the first branch exchanges heat with the heat supply network circulating water in the peak heater 7, the heat supply network circulating water return water is heated to form heat supply network circulating water for water supply and is discharged from a water side outlet of the peak heater 7, heat is supplied to the outside, and the requirement of heat supply load is met; the first branch medium pressure cylinder exhaust steam is condensed into hydrophobic steam and is exhausted from a steam side outlet of the spike heater 7, the hydrophobic steam enters the condenser 8 from the upper part of the condenser 8 to be cooled (as shown in figure 2) or is divided into two branches (as shown in figure 3), the first branch hydrophobic steam enters the condenser 8 from the upper part of the condenser 8 to be cooled, and the second branch hydrophobic steam enters a water well of the condenser 8.

The exhaust steam of the intermediate pressure cylinder of the second branch enters the back pressure turbine 4 through a steam inlet of the back pressure turbine 4 to do work, and drives the additional generator 6 to generate electricity.

The back pressure turbine exhaust steam to low pressure cylinder regulating valve 22 is opened and the exhaust steam heat exchanger steam inlet electric valve 31 is closed. The exhaust steam of the back pressure turbine discharged from the steam outlet of the back pressure turbine 4 enters the low pressure cylinder 3 through the steam inlet of the low pressure cylinder 3, and is used for cooling the low pressure cylinder 3, so that the operation requirement is met.

The steam inlet electric valve 21 of the condenser is opened, the exhaust steam of the intermediate pressure cylinder in the second branch enters the condenser 8 through the steam inlet 4 of the back pressure turbine, the steam outlet 4 of the back pressure turbine, the steam inlet 3 of the low pressure cylinder, the steam outlet 3 of the low pressure cylinder and the upper part of the condenser 8 to be condensed, and the exhaust steam and the drain water of the low pressure cylinder entering the condenser 8 are condensed and cooled by the circulating water of the large engine.

The vacuumizing electric valve 20, the large machine circulating water backwater electric valve 18 and the large machine circulating water outlet electric valve 19 are opened. The circulating water of the main engine enters the condenser 8 through the water side inlet of the condenser 8. In the condenser 8, the large machine circulating water backwater is heated to form large machine circulating water outlet water, and the large machine circulating water outlet water is discharged through a water side outlet of the condenser 8. After the heat exchange, the water is cooled, the discharged steam of the low-pressure cylinder is condensed to form condensed water, and the condensed water are both stored in a water well of the condenser 8.

Referring to fig. 2, the spike heater hydrophobic to condenser adjustment valve 16 is opened and the spike heater hydrophobic to condenser well electric valve 17 is closed so that all of the hydrophobic enters the condenser 8 from the upper portion of the condenser 8 to be cooled. Meanwhile, the electric valve 36 for the exhaust steam heat exchanger bypass is opened, the exhaust steam heat exchanger is short-circuited, and drainage of a water well of the condenser 8 (consisting of cooled drainage in the condenser 8 and condensation water formed after the drainage of the low-pressure cylinder is condensed) directly enters a condensation water system through the exhaust steam heat exchanger bypass.

Alternatively, referring to fig. 3, the spike heater hydrophobic to condenser adjustment valve 16 and the spike heater hydrophobic to condenser well electric valve 17 are opened. So that the drainage is divided into the first branch drainage and the second branch drainage, and the first branch drainage also enters the condenser 8 from the upper part of the condenser 8 to be cooled. The second branch drains water and directly enters a water well of the condenser 8. The drainage of the water well of the condenser 8 (including the drainage cooled in the condenser 8, the drainage not cooled and the condensation water formed after the low pressure cylinder drainage is condensed) directly enters the condensation water system through the waste steam heat exchanger bypass.

Referring to fig. 4, 5, 6 and 7, when the medium pressure cylinder exhaust steam is divided into three branches:

the middle pressure cylinder exhaust steam is divided into a first branch middle pressure cylinder exhaust steam, a second branch middle pressure cylinder exhaust steam and a third branch middle pressure cylinder exhaust steam. The steam exhaust of the intermediate pressure cylinder in the first branch accounts for most of the total steam exhaust of the intermediate pressure cylinder 2, the steam exhaust amount of the intermediate pressure cylinder in the second branch accounts for a very small part, and the steam exhaust amount of the intermediate pressure cylinder in the third branch is 5-15 t/h.

The steam extraction check valve 11, the steam extraction quick closing valve 12 and the steam extraction electric valve 13 are opened, and the spike heater steam inlet adjusting valve 15 is adjusted to be at a proper opening degree. The first branch intermediate pressure cylinder exhaust steam enters the spike heater 7 from the exhaust steam port of the intermediate pressure cylinder 2 through the steam inlet of the spike heater 7. The valve can be opened to enable the circulating water backwater of the heat supply network to directly enter the peak heater 7 through the water side inlet of the peak heater 7 (such as the working conditions of fig. 4 and 6), or heated by the exhaust steam heat exchanger 10 and then enter the water side inlet of the peak heater 7 through the water side inlet of the peak heater 7 to enter the peak heater 7 (such as the working conditions of fig. 5 and 7), the exhaust steam of the first branch intermediate pressure cylinder exchanges heat with the circulating water of the heat supply network (the circulating water backwater of the heat supply network directly entering the peak heater 7 and the circulating water of the heat supply network entering the peak heater 7 are collectively called circulating water of the heat supply network) in the peak heater 7, the circulating water of the heat supply network is heated to form circulating water supply of the heat supply network, and the circulating water of the heat supply network is discharged from; the first branch is condensed into drain water, the drain water is discharged from a steam side outlet of the spike heater 7, the drain water enters the condenser 8 from the upper part of the condenser 8 to be cooled (as shown in fig. 4 and 5) or is divided into two branches (as shown in fig. 6 and 7), the drain water in the first branch enters the condenser 8 from the upper part of the condenser 8 to be cooled, and the drain water in the second branch directly enters a water well of the condenser 8.

The back pressure turbine steam inlet regulating valve 25 is adjusted to a suitable opening degree. The exhaust steam of the intermediate pressure cylinder of the second branch enters the back pressure turbine 4 through a steam inlet of the back pressure turbine 4 to do work, and drives the additional generator 6 to generate electricity.

The back pressure turbine exhaust steam to low pressure cylinder regulating valve 22 is closed, and simultaneously the exhaust steam heat exchanger steam inlet electric valve 31 is opened. All the exhausted steam of the back pressure turbine enters the exhausted steam heat exchanger 10 through a steam inlet of the exhausted steam heat exchanger 10 to be condensed.

The condensate cooling water regulating valve 27 and the intermediate pressure cylinder steam exhaust to low pressure cylinder regulating valve 28 are opened. The condensed water is cooled by water and enters the temperature and pressure reducing device 26, the steam discharged by the intermediate pressure cylinder of the third branch enters the low pressure cylinder 3 after being subjected to temperature and pressure reduction through the temperature and pressure reducing device 26, and the low pressure cylinder 3 of the steam turbine is cooled to meet the operation requirement.

The steam inlet electric valve 21 of the condenser is opened. The low-pressure cylinder exhaust steam enters the condenser 8 through the upper part of the condenser 8 to be cooled. Therefore, the discharged steam and the drained water entering the low-pressure cylinder of the condenser 8 are condensed and cooled by the large machine circulating water.

The vacuumizing electric valve 20, the large machine circulating water backwater electric valve 18 and the large machine circulating water outlet electric valve 19 are opened. The circulating water of the main engine enters the condenser 8 through the water side inlet of the condenser 8. In the condenser 8, the large machine circulating water backwater is heated to form large machine circulating water outlet water, and the large machine circulating water outlet water is discharged through a water side outlet of the condenser 8. The drained water is cooled after heat exchange, the low-pressure cylinder exhaust steam is condensed to form condensed water, and the cooled drained water and the condensed water are mixed and stored in a water well of the condenser 8.

Referring to fig. 4 and 6, the waste steam heat exchanger condensed water outlet electric valve 35 and the waste steam heat exchanger condensed water inlet electric valve 34 are opened, and water discharged from the water well of the condenser 8 enters the waste steam heat exchanger 10 to be heated and then is sent to a condensed water system. Referring to fig. 5 and 7, the exhaust steam heat exchanger heat supply network circulating water outlet electric valve 33, the exhaust steam heat exchanger heat supply network circulating water return electric valve 32 and the exhaust steam heat exchanger bypass electric valve 36 are opened, water discharged from the water well of the condenser 8 enters the condensate system through the exhaust steam heat exchanger bypass, and the heat supply network circulating water return enters the exhaust steam heat exchanger 10 to be heated and is sent to the peak heater water side inlet as heat supply network circulating water outlet. In summary, in the present embodiment, only one of the water discharged from the well of the condenser 8 and the return water of the heat supply network circulating water enters the exhaust steam heat exchanger 10 for heating, and when the return water of the heat supply network circulating water enters the exhaust steam heat exchanger 10 for heating, the water discharged from the well of the condenser 8 is directly sent to the condensate system.

And opening a regulating valve 30 from the exhaust steam heat exchanger to the water well of the condenser, and enabling condensed water formed after the exhaust steam of the back pressure type steam turbine in the exhaust steam heat exchanger 10 is condensed to enter the water well of the condenser 8 through a steam side outlet of the exhaust steam heat exchanger 10.

Referring to fig. 4 and 5, the spike heater hydrophobic to condenser regulating valve 16 is opened and the spike heater hydrophobic to condenser well electric valve 17 is closed, so that all the hydrophobic discharged from the spike heater 7 enters the condenser 8 from the upper part of the condenser to be cooled. In this condition, the drainage of the well of the condenser 8 includes the condensate formed by condensation of the drain, low-pressure cylinder drain steam cooled in the condenser 8 and the condensate formed by condensation of the back-pressure turbine exhaust steam in the exhaust steam heat exchanger 10.

Alternatively, referring to fig. 6 and 7, the spike heater drain-to-condenser regulating valve 16 and the spike heater drain-to-condenser well electric valve 17 are opened, so that the drain is divided into the first branch drain and the second branch drain, the first branch drain is also fed into the condenser 8 from the upper part of the condenser to be cooled, and the second branch drain is fed into the well of the condenser 8 directly. The drainage of the water well of the condenser 8 at this time includes drainage which is cooled in the condenser 8, drainage which is not cooled, condensation water which is formed by condensation of low-pressure cylinder exhaust steam, and condensation water which is formed by condensation of back-pressure turbine exhaust steam in the exhaust steam heat exchanger 10.

In one operating state, the valve, which is not explicitly described as open and which is used to open and close the line, is in the closed state.

The second heating mode is described as follows.

The main steam flow entering the high pressure cylinder 1 of the steam turbine is increased, so that the main steam flow is larger than the main steam flow in the first heat supply mode, the distribution amount of the steam exhausted by the intermediate pressure cylinder in the first branch is unchanged, the excessive steam exhausted by the intermediate pressure cylinder can supplement the steam exhausted by the back pressure steam turbine to do work under the premise of ensuring that the heat supply load is unchanged, namely the distribution amount of the steam exhausted by the intermediate pressure cylinder in the second branch in the second heat supply mode is larger than the distribution amount of the steam exhausted by the intermediate pressure cylinder in the second branch in the first heat supply mode.

Referring to fig. 8, 9, 10 and 11, when the exhaust steam of the intermediate pressure cylinder is divided into two branches:

the steam exhaust of the intermediate pressure cylinder is divided into a first branch steam exhaust of the intermediate pressure cylinder and a second branch steam exhaust of the intermediate pressure cylinder, the steam exhaust of the intermediate pressure cylinder in the first branch accounts for most of the total steam exhaust of the intermediate pressure cylinder 2, and the steam exhaust amount of the intermediate pressure cylinder in the second branch is larger than that of the intermediate pressure cylinder in the first heat supply mode.

The steam extraction check valve 11, the steam extraction quick closing valve 12 and the steam extraction electric valve 13 are opened, and the peak heater steam inlet regulating valve 15 and the back pressure turbine steam inlet regulating valve 25 are adjusted to proper opening degrees. The first branch intermediate pressure cylinder exhaust steam enters the spike heater 7 from the exhaust steam port of the intermediate pressure cylinder 2 through the steam inlet of the spike heater 7. The valve between the heat supply network circulating water return pipeline and the peak heater 7 can be opened, so that the heat supply network circulating water return water directly enters the peak heater 7 through the water side inlet of the peak heater 7 (such as the working conditions of figures 8 and 10), or the heat supply network circulating water return water is heated by the exhaust steam heat exchanger 10 and then enters the peak heater 7 through the water side inlet of the peak heater 7 (such as the working conditions of figures 9 and 11), the steam discharged by the pressure cylinder in the first branch exchanges heat with the heat supply network circulating water (the heat supply network circulating water return water directly entering the peak heater 7 and the heat supply network circulating water outlet water entering the peak heater 7 are collectively called as heat supply network circulating water) in the peak heater 7, and the heat supply network circulating water is heated to form heat supply network circulating water which is discharged from the water side outlet of the peak heater 7 to supply heat outside and meet the; the first branch is condensed into drain water, the drain water is discharged from a steam side outlet of the spike heater 7, the drain water enters the condenser 8 from the upper part of the condenser to be cooled (as shown in figures 8 and 9) or is divided into two branches (as shown in figures 10 and 11), the drain water in the first branch enters the condenser 8 from the upper part of the condenser to be cooled, and the drain water in the second branch directly enters a water well of the condenser 8.

The back pressure turbine exhaust steam to low pressure cylinder regulating valve 22, the condenser steam inlet electric valve 21 and the exhaust steam heat exchanger steam inlet electric valve 31 are opened, the opening degree of the back pressure turbine exhaust steam to low pressure cylinder regulating valve 22 is regulated, so that the back pressure turbine exhaust steam discharged from the steam discharge port of the back pressure turbine 4 is divided into two branches, the steam discharge amount of the first branch back pressure turbine is 5t/h-15t/h, and the first branch back pressure turbine exhaust steam enters the low pressure cylinder 3 through the steam inlet of the low pressure cylinder 3 and is used for cooling the low pressure cylinder 3, and therefore the operation requirement is met. The exhaust steam of the first branch back pressure turbine forms low-pressure cylinder exhaust steam through the low-pressure cylinder 3, and the low-pressure cylinder exhaust steam enters the condenser 8 through the exhaust steam port of the low-pressure cylinder 3 and the upper part of the condenser 8 to be condensed. The exhaust steam of the back pressure turbine of the second branch enters the exhaust steam heat exchanger 10 through a steam inlet of the exhaust steam heat exchanger 10 and is condensed to form condensed water which enters a water well of the condenser 8. Therefore, the low-pressure cylinder exhaust steam entering the condenser 8, the exhaust steam of the second branch back pressure turbine and the drain water are condensed and cooled by the main circulating water.

Referring to fig. 8 and 10, the waste steam heat exchanger condensed water outlet electric valve 35 and the waste steam heat exchanger condensed water inlet electric valve 34 are opened, and water discharged from the water well of the condenser 8 enters the waste steam heat exchanger 10 to be heated and sent to the condensed water system. Referring to fig. 9 and 11, the exhaust steam heat exchanger heat supply network circulating water outlet electric valve 33, the exhaust steam heat exchanger heat supply network circulating water return electric valve 32 and the exhaust steam heat exchanger bypass electric valve 36 are opened, water discharged from the water well of the condenser 8 enters the condensate system through the exhaust steam heat exchanger bypass, and the heat supply network circulating water return enters the exhaust steam heat exchanger 10 to be heated and is sent to the peak heater water side inlet as heat supply network circulating water outlet. In summary, in the present embodiment, only one of the water discharged from the well of the condenser 8 and the return water of the heat supply network circulating water enters the exhaust steam heat exchanger 10 for heating, and when the return water of the heat supply network circulating water enters the exhaust steam heat exchanger 10 for heating, the water discharged from the well of the condenser 8 is directly sent to the condensate system.

Referring to fig. 8 and 9, the spike heater hydrophobic to condenser regulating valve 16 is opened and the spike heater hydrophobic to condenser well electric valve 17 is closed, so that all the hydrophobic discharged from the spike heater 7 enters the condenser 8 from the upper part of the condenser to be cooled. Under the working condition, the drainage of the water well of the condenser 8 comprises the condensed water formed after the drainage cooled in the condenser 8 and the exhaust steam of the low-pressure cylinder are condensed and the condensed water formed after the exhaust steam of the back pressure turbine is condensed in the exhaust steam heat exchanger 10.

Or, referring to fig. 10 and 11, the peak heater dewatering-to-condenser regulating valve 16 is opened and the peak heater dewatering-to-condenser well electric valve 17 is opened, so that the drainage discharged by the peak heater 7 is divided into two branches, the drainage of the first branch enters the condenser 8 from the upper part of the condenser to be cooled, and the drainage of the second branch directly enters the well of the condenser 8. Under the working condition, the drainage of the water well of the condenser 8 comprises the condensed water formed by condensation of cooled drainage, uncooled drainage and low-pressure cylinder exhaust steam in the condenser 8 and the condensed water formed by condensation of the back pressure turbine exhaust steam in the exhaust steam heat exchanger 10.

Referring to fig. 12, 13, 14 and 15, when the medium pressure cylinder exhaust steam is divided into three branches:

the middle pressure cylinder exhaust steam is divided into a first branch middle pressure cylinder exhaust steam, a second branch middle pressure cylinder exhaust steam and a third branch middle pressure cylinder exhaust steam. The steam exhaust of the intermediate pressure cylinder in the first branch accounts for most of the total steam exhaust of the intermediate pressure cylinder 2, the steam exhaust amount of the intermediate pressure cylinder in the second branch is increased compared with that in the first heat supply mode, and the steam exhaust amount of the intermediate pressure cylinder in the third branch is 5t/h-15 t/h. A valve between the heat supply network circulating water return pipeline and the peak heater 7 is opened, so that the heat supply network circulating water return water can directly enter the peak heater 7 through a water side inlet of the peak heater 7 (as shown in fig. 12 and 14), or enters the peak heater 7 through a water side inlet of the peak heater 7 after being heated by the exhaust steam heat exchanger 10 (as shown in fig. 13 and 15), the exhaust steam of the pressure cylinder in the first branch is subjected to heat exchange with the heat supply network circulating water in the peak heater 7, the heat supply network circulating water is heated to form heat supply network circulating water, the heat supply network circulating water is discharged from a water side outlet of the peak heater 7, and heat is supplied to the outside to meet the requirement of a heat supply; the first branch is condensed into drain water, the drain water is discharged from a steam side outlet of the spike heater 7, the drain water enters the condenser 8 from the upper part of the condenser to be cooled (as shown in figures 12 and 13) or is divided into two branches (as shown in figures 14 and 15), the drain water in the first branch enters the condenser 8 from the upper part of the condenser to be cooled, and the drain water in the second branch directly enters a water well of the condenser 8.

The back pressure turbine exhaust steam to low pressure cylinder regulating valve 21 is closed, and simultaneously the exhaust steam heat exchanger steam inlet electric valve 31 is opened. All the exhausted steam of the back pressure turbine enters the exhausted steam heat exchanger 10 through a steam inlet of the exhausted steam heat exchanger 10 to be condensed.

The steam inlet electric valve 21 of the condenser is opened. The low-pressure cylinder exhaust steam enters the condenser 8 through the upper part of the condenser 8 to be condensed. Therefore, the discharged steam and the drained water entering the low-pressure cylinder of the condenser 8 are condensed and cooled by the large machine circulating water.

Referring to fig. 12 and 14, the waste steam heat exchanger condensed water outlet electric valve 35 and the waste steam heat exchanger condensed water inlet electric valve 34 are opened, and water discharged from the water well of the condenser 8 enters the waste steam heat exchanger 10 to be heated and then is sent to a condensed water system. Referring to fig. 13 and 15, the exhaust steam heat exchanger heat supply network circulating water backwater electric valve 32, the exhaust steam heat exchanger heat supply network circulating water outlet electric valve 33 and the exhaust steam heat exchanger bypass electric valve 36 are opened, water discharged from the water well of the condenser 8 enters the condensate system through the exhaust steam heat exchanger bypass, and the heat supply network circulating water backwater enters the exhaust steam heat exchanger 10 to be heated and is sent to the peak heater water side inlet as heat supply network circulating water outlet water. In summary, in the present embodiment, only one of the water discharged from the well of the condenser 8 and the return water of the heat supply network circulating water enters the exhaust steam heat exchanger 10 for heating, and when the return water of the heat supply network circulating water enters the exhaust steam heat exchanger 10 for heating, the water discharged from the well of the condenser 8 is directly sent to the condensate system.

Referring to fig. 12 and 13, the spike heater hydrophobic to condenser adjustment valve 16 is opened and the spike heater hydrophobic to condenser well electric valve 17 is closed so that all of the hydrophobic discharged from the spike heater 7 enters the condenser 8 from the upper part of the condenser to be cooled. Under this condition, the water drain of the water well of the condenser 8 includes the condensed water formed by condensing the drain water cooled in the condenser 8 and the low-pressure cylinder exhaust steam and the condensed water formed by condensing the back-pressure turbine exhaust steam in the exhaust steam heat exchanger 10.

Alternatively, referring to fig. 14 and 15, the spike heater drain-to-condenser regulating valve 16 and the spike heater drain-to-condenser well electric valve 17 are opened, so that the drain is divided into the first branch drain and the second branch drain, the first branch drain still enters the condenser 8 from the upper part of the condenser to be cooled, and the second branch drain directly enters the well of the condenser 8. Under the working condition, the drainage of the water well of the condenser 8 comprises the condensed water formed by condensation of cooled drainage, uncooled drainage and low-pressure cylinder exhaust steam in the condenser 8 and the condensed water formed by condensation of the back pressure turbine exhaust steam in the exhaust steam heat exchanger 10.

In the non-heat supply period, the low-pressure cylinder 3 adopts the low-pressure rotor (with blades) of the original unit, the exhaust steam of the intermediate pressure cylinder enters the low-pressure cylinder 3 to do work, and the exhaust steam parameters are restored to the normal level, namely, the steam turbine is restored to the pure condensing mode to operate.

The two different heat supply operation modes are provided at the initial and final stages of heat supply and the secondary cold period, so that the heat and electrolytic coupling capacity of the unit is fully improved, wherein the heat and electrolytic coupling capacity of the additional generator 6 driven by the back pressure turbine 4 is strongest and is stronger than that of auxiliary equipment such as a heat supply network circulating pump, a water supply pump, an induced draft fan and the like driven by the back pressure turbine.

In the severe cold period of heat supply, the heat supply load is the maximum, the main steam flow is the rated flow, under the working condition, the unit no longer has the power generation load peak regulation capacity, and the operation mode of 'fixing power by heat' is adopted, and the operation mode refers to the working condition that the steam discharge of the intermediate pressure cylinder in the first heat supply mode is divided into two branches.

The heat supply system of the embodiment can meet the heat supply of the existing low-pressure cylinder optical axis heat supply technology, can avoid the defects of poor peak regulation capability and inherent characteristic limitation of the low-pressure cylinder optical axis heat supply technology of 'fixing power with heat', can increase the flow of main steam to operate particularly in the working conditions of the initial stage and the final stage of heat supply, small heat supply load demand and large power generation load demand, removes the steam exhausted by the intermediate pressure cylinder for heat supply, and the exhausted steam of the excess intermediate pressure cylinder enters the back pressure turbine 4 to do work to drive the additional generator 6 to generate power (or auxiliary equipment such as a heat network circulating pump, a water supply pump, a draught fan and the like to do work) so as to meet the working conditions of small heat supply load demand. The steam flow entering the peak heater 7 and the back pressure turbine 4 can be adjusted according to different heat supply load and power generation load scheduling requirements, and the heat and electrolytic coupling capacity of the unit is fully improved.

Furthermore, the above designs of the drainage and back pressure turbine exhaust steam based on the peak heater 7 and the low pressure cylinder exhaust steam heat supply are all for improving the reasonable graded utilization of energy and improving the safe operating environment of the condensate pump and the shaft seal cooler.

Furthermore, the added exhaust steam heat exchanger 10 heats the drainage of the water well of the condenser 8 by using the exhaust steam of the back pressure turbine, so that the exhaust steam of the back pressure turbine in the back pressure turbine 4 is condensed to form condensed water, thereby preventing the drainage temperature of the water well of the condenser 8 from being too low and generating low-temperature impact on the deaerator and ensuring the safe operation of the unit. The back pressure turbine exhaust steam can also be used for heating the circulating water return of the heat supply network, and the heat energy is fully utilized.

Further, compared with the method that the low-pressure cylinder 3 is cooled after the intermediate-pressure cylinder exhaust steam (5-15t/h) is used for temperature and pressure reduction, the low-pressure cylinder 3 is directly cooled by the back pressure steam turbine exhaust steam (5-15t/h), the useful energy loss of the steam is reduced, and the energy utilization efficiency is improved.

Further, the additional hydraulic shut-off valve 24 completely shuts off the intermediate pressure cylinder 2 and the low pressure cylinder 3.

Claims

1. A heating system based on a turbine low-pressure optical axis technology is characterized by comprising a turbine, a peak heater, a waste steam heat exchanger and a back pressure turbine;

the steam turbine comprises a high-pressure cylinder, a medium-pressure cylinder and a low-pressure cylinder which is transformed into an optical axis;

the steam outlet of the intermediate pressure cylinder can be selectively communicated with the steam inlet of the back pressure steam turbine and the steam inlet of the peak heater in an on-off mode and in a flow-adjustable mode;

and the steam outlet of the back pressure steam turbine can be selectively communicated with the steam inlet of the low pressure cylinder and the steam side inlet of the exhaust steam heat exchanger in an on-off and flow-adjustable mode.

2. Heating system based on turbine low pressure optical axis technology according to claim 1,

the steam outlet of the intermediate pressure cylinder is communicated with the steam inlet of the peak heater and the steam inlet of the back pressure turbine through pipelines, each pipeline comprises a shared pipeline section, a first branch pipeline section and a second branch pipeline section, the first branch pipeline section is connected between the peak heater and the shared pipeline section, and the second branch pipeline section is connected between the back pressure turbine and the shared pipeline section;

an extraction check valve, an extraction quick closing valve, an extraction electric valve and an orifice plate flowmeter are sequentially arranged on the common pipeline section along the direction of the intermediate pressure cylinder pointing to the peak heater;

the first branch pipeline section is provided with a peak heater steam inlet regulating valve;

and a back pressure type steam turbine steam inlet regulating valve is arranged on the second branch pipeline section.

3. Heating system based on turbine low pressure optical axis technology according to claim 1,

the steam outlet of the intermediate pressure cylinder is selectively communicated with the steam inlet of the low pressure cylinder in a switching mode, and a temperature and pressure reducing device is arranged between the steam outlet of the intermediate pressure cylinder and the steam inlet of the low pressure cylinder.

4. The heating system based on the turbine low-pressure optical axis technology according to claim 3, further comprising a condenser;

the steam outlet of the low pressure cylinder is communicated with the steam inlet of the condenser through a pipeline, and the pipeline is provided with a steam inlet electric valve of the condenser;

the steam outlet of the intermediate pressure cylinder is selectively communicated with the steam inlet of the low pressure cylinder through a first pipeline and a second pipeline which are connected in parallel;

a hydraulic shutoff valve is arranged on the first pipeline;

the temperature and pressure reduction device, the flow meter of the steam exhaust to low-pressure cylinder hole plate of the intermediate pressure cylinder and the regulating valve of the steam exhaust to low-pressure cylinder of the intermediate pressure cylinder are arranged on the second pipeline along the direction from the intermediate pressure cylinder to the low-pressure cylinder;

the desuperheating water inlet of the desuperheating pressure reducer is connected with a condensed water cooling water pipeline, and a condensed water cooling water regulating valve is arranged on a pipeline connected with the desuperheating pressure reducer and the condensed water cooling water pipeline;

the steam outlet of the back pressure turbine is communicated with the steam inlet of the low pressure cylinder through a pipeline, and a back pressure turbine exhaust steam to low pressure cylinder hole plate flowmeter and a back pressure turbine exhaust steam to low pressure cylinder regulating valve are arranged on the pipeline along the direction from the steam outlet of the back pressure turbine to the steam inlet of the low pressure cylinder;

the steam outlet of the back pressure steam turbine is communicated with the steam side inlet of the waste steam heat exchanger through a pipeline, and the pipeline is provided with a steam inlet electric valve of the waste steam heat exchanger.

5. The heating system based on the turbine low-pressure optical axis technology according to claim 3, further comprising a condenser;

and the steam side outlet of the spike heater is selectively communicated with the upper part of the condenser and the condenser water well in an on-off manner, and the steam side outlet of the exhaust steam heat exchanger is communicated with the condenser water well.

6. Heating system based on turbine low pressure optical axis technology according to claim 5,

the steam side outlet of the peak heater is communicated with the upper part of the condenser through a pipeline, and the pipeline is provided with a peak heater drain to condenser regulating valve;

the steam side outlet of the spike heater is communicated with the condenser well through a pipeline, and an electric valve for draining water from the spike heater to the condenser well is arranged on the pipeline;

the water side inlet of the peak heater is selectively communicated with the heat supply network circulating water return pipeline and the heat supply network circulating water outlet pipeline in a switching mode;

and a water side outlet of the peak heater is communicated with a circulating water supply pipeline of a heat supply network.

7. Heating system based on turbine low pressure optical axis technology according to claim 5,

the water side inlet of the condenser is selectively communicated with a main machine circulating water return pipeline in an on-off mode, the water side outlet of the condenser is selectively communicated with a main machine circulating water outlet pipeline in an on-off mode, the water side inlet of the exhaust steam heat exchanger is selectively communicated with the condenser well and the heat supply network circulating water return pipeline in an on-off mode, and the water side outlet of the exhaust steam heat exchanger is selectively communicated with a condensate system and the heat supply network circulating water outlet pipeline in an on-off mode.

8. Heating system based on turbine low pressure optical axis technology according to claim 7,

a water side inlet of the condenser is communicated with a circulating water return pipeline of the large engine through a pipeline, and the pipeline is provided with a circulating water return electric valve of the large engine;

the water side outlet of the condenser is communicated with a circulating water outlet pipeline of the large engine through a pipeline, and the pipeline is provided with a circulating water outlet electric valve of the large engine;

the water side inlet of the exhaust steam heat exchanger is communicated with a water well of a condenser through a pipeline, and a condensate pump and an electric valve for the condensate water inlet of the exhaust steam heat exchanger are arranged on the pipeline;

the water side inlet of the exhaust steam heat exchanger is communicated with a circulating water return pipeline of a heat supply network through a pipeline, and the pipeline is provided with an exhaust steam heat exchanger circulating water return electric valve of the heat supply network;

the water side outlet of the exhaust steam heat exchanger is communicated with a condensed water system through a pipeline, and the pipeline is provided with an electric valve for discharging condensed water of the exhaust steam heat exchanger;

and a water side outlet of the exhaust steam heat exchanger is communicated with a circulating water outlet pipeline of the heat supply network through a pipeline, and the pipeline is provided with an electric valve for the circulating water outlet of the heat supply network of the exhaust steam heat exchanger.

9. Heating system based on turbine low pressure optical axis technology according to claim 8,

the waste steam heat exchanger is characterized in that a waste steam heat exchanger water side bypass is arranged at the waste steam heat exchanger, the waste steam heat exchanger water side bypass is connected with a pipeline which is arranged in the waste steam heat exchanger and used for communicating a water side inlet and a water side outlet in parallel, a waste steam heat exchanger bypass electric valve is arranged on the waste steam heat exchanger water side bypass, an inlet of the waste steam heat exchanger water side bypass is positioned at the upstream of a waste steam heat exchanger condensed water inlet electric valve, and an outlet of the waste steam heat exchanger water side bypass is positioned at the downstream of the waste steam heat exchanger condensed water outlet electric valve.

10. The heating system based on the turbine low-pressure optical axis technology according to claim 1, characterized by further comprising energy supply equipment;

the back pressure steam turbine with need energy supply equipment to connect, need energy supply equipment for additional generator, heat supply network circulating pump, feed pump or draught fan.