CN108343479B - Two-unit-based back condensation and extraction heat supply system and adjusting method - Google Patents
Two-unit-based back condensation and extraction heat supply system and adjusting method Download PDFInfo
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- CN108343479B CN108343479B CN201810171077.3A CN201810171077A CN108343479B CN 108343479 B CN108343479 B CN 108343479B CN 201810171077 A CN201810171077 A CN 201810171077A CN 108343479 B CN108343479 B CN 108343479B
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
- F01K7/00—Steam engine plants characterised by the use of specific types of engine; Plants or engines characterised by their use of special steam systems, cycles or processes; Control means specially adapted for such systems, cycles or processes; Use of withdrawn or exhaust steam for feed-water heating
- F01K7/16—Steam engine plants characterised by the use of specific types of engine; Plants or engines characterised by their use of special steam systems, cycles or processes; Control means specially adapted for such systems, cycles or processes; Use of withdrawn or exhaust steam for feed-water heating the engines being only of turbine type
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D25/00—Component parts, details, or accessories, not provided for in, or of interest apart from, other groups
- F01D25/08—Cooling; Heating; Heat-insulation
- F01D25/12—Cooling
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
- F01K11/00—Plants characterised by the engines being structurally combined with boilers or condensers
- F01K11/02—Plants characterised by the engines being structurally combined with boilers or condensers the engines being turbines
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
- F01K13/00—General layout or general methods of operation of complete plants
- F01K13/02—Controlling, e.g. stopping or starting
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
- F01K17/00—Using steam or condensate extracted or exhausted from steam engine plant
- F01K17/02—Using steam or condensate extracted or exhausted from steam engine plant for heating purposes, e.g. industrial, domestic
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E20/00—Combustion technologies with mitigation potential
- Y02E20/14—Combined heat and power generation [CHP]
Abstract
The invention relates to a condensing back-pumping heat supply system based on two units and an adjusting method. The cascade utilization of energy can improve the utilization efficiency of the system energy. The invention comprises a first cogeneration unit, a second cogeneration unit and a cooling steam system, wherein the cooling steam system is provided with a pressure reducing device and a temperature reducing device, the first cogeneration unit is provided with a cooling steam system, a steam inlet of a cooling steam pipe is connected with a low-pressure cylinder back-heating steam extraction port of the second cogeneration unit, and a steam outlet of the cooling steam pipe is connected with a low-pressure cylinder steam inlet and a low-pressure cylinder back-heating steam extraction port of the second cogeneration unit. According to the invention, indirect heat exchange is utilized to reduce the temperature of the cooling steam, so that the quality of the cooling steam is ensured; the backheating extraction steam of the low-pressure cylinder of the turbine after the other working is used as a steam source of cooling steam, so that the irreversible loss caused by temperature and pressure reduction of the cooling steam is reduced, the reliability of the cooling steam source is ensured, and the safety of the operation of the low-pressure cylinder of the turbine without steam inflow is improved.
Description
Technical Field
The invention belongs to the technical field of cogeneration, and particularly relates to a condensing back heat supply system based on two units and an adjusting method, which are particularly suitable for a thermal power plant with two units.
Background
At present, the policy in China gradually pays attention to popularization of new energy sources, and reduces the proportion of thermal power generating units. For thermal power plants, the exhaust steam of the steam turbine is usually directly discharged through an air cooling or water cooling mode, which causes huge cold end loss. For example, the energy utilization rate of a 300MW subcritical pure condensing unit is about 38%, wherein the cold end loss is about 45%, the energy utilization rate of the unit is improved to 60% after steam extraction and heat supply are adopted, but 20% of condensed low-temperature waste heat is discharged, and the heat is difficult to directly utilize due to low grade. Meanwhile, as the power grid is used for absorbing new energy and power, the requirements on the thermal power flexibility of the coal motor unit are continuously enhanced, and the coal motor unit needs to realize ultralow-load operation to meet the peak regulation requirement of the power grid, so that the coal-fired thermoelectric unit is extremely challenged.
At present, the chinese patent with the application number 201711165679.X discloses a cooling system and a working method for cutting off heat supply of a low-pressure cylinder, which realize that the low-pressure cylinder is effectively cooled when the low-pressure cylinder does not enter steam, and the medium-pressure cylinder is directly used for exhausting steam as cooling steam, and because the temperature and pressure parameters are too high, the temperature and the pressure are required to be reduced firstly, irreversible loss is caused to a certain extent, and on the other hand, when water spraying is adopted for reducing the temperature, water drops are easily caused in the cooling steam to reduce the quality of the cooling steam. Aiming at the phenomenon and combining with the fact that two cogeneration units are generally arranged in a domestic thermal power plant, the invention and creation are carried out, and the low-pressure cylinder backheating extraction steam of the other cogeneration unit is utilized as a cooling steam source when the low-pressure cylinder of the cogeneration unit does not enter steam.
Disclosure of Invention
Based on the above situation, the invention overcomes the defects existing in the prior art, and provides the two-unit-based back condensation heat supply system and the adjusting method which are reasonable in design, reliable in performance and beneficial to realizing energy cascade utilization.
The invention solves the problems by adopting the following technical scheme: the condensing back-pumping heat supply system based on the two units comprises a first cogeneration unit, a second cogeneration unit and a cooling steam system; the method is characterized in that:
the first cogeneration unit comprises: the system comprises a first turbine medium pressure cylinder, a first turbine low pressure cylinder, a first condenser, a first condensate pump and a first regenerative system; the steam outlet of the first steam turbine medium pressure cylinder is connected with the steam inlet of the first steam turbine low pressure cylinder through a first communicating pipe, a first back pressure butterfly valve and a first condensation butterfly valve are sequentially arranged on the first communicating pipe along the steam flow direction, the first steam turbine medium pressure cylinder is connected with a first heating steam extraction pipe, the steam outlet of the first steam turbine low pressure cylinder is connected with a first condenser, and the first condenser is connected with a first condensate pump; the first regenerative system comprises: the system comprises a first-stage low-pressure heater and a first-stage second-stage low-pressure heater, wherein a water inlet of the first-stage low-pressure heater is connected with a water outlet of a first condensate pump, a steam inlet of the first-stage low-pressure heater is connected with a first-stage steam extraction port of a first turbine low-pressure cylinder through a first-stage steam extraction pipe, a seventh gate valve is arranged on the first-stage steam extraction pipe, a water inlet of the first-stage second-pressure heater is connected with a water outlet of the first-stage low-pressure heater, a steam inlet of the first-stage second-stage low-pressure heater is connected with a second-stage steam extraction port of the first turbine low-pressure cylinder through a first-stage steam extraction pipe, and an eighth gate valve is arranged on the first-stage second-stage steam extraction pipe;
the second cogeneration unit comprises: a second turbine medium pressure cylinder, a second turbine low pressure cylinder, a second condenser, a second condensate pump and a second regenerative system; the exhaust port of the medium pressure cylinder of the second steam turbine is connected with the steam inlet of the low pressure cylinder of the second steam turbine through a second communicating pipe, a second condensation butterfly valve is arranged on the second communicating pipe, the medium pressure cylinder of the second steam turbine is connected with a second heating steam extraction pipe, the exhaust port of the low pressure cylinder of the second steam turbine is connected with a second condenser, and the second condenser is connected with a second condensate pump; the second regenerative system comprises: the water inlet of the second low-pressure heater is connected with the water outlet of the second condensate pump, the steam inlet of the second low-pressure heater is connected with the first steam extraction port of the second turbine low-pressure cylinder through a second first steam extraction pipe, the water inlet of the second low-pressure heater is connected with the water outlet of the second low-pressure heater, and the steam inlet of the second low-pressure heater is connected with the second steam extraction port of the second turbine low-pressure cylinder through a second steam extraction pipe;
the cooling steam system includes: the cooling steam pipe, pressure reducing device, temperature reducing device and steam parameter measuring device are installed in proper order along steam flow direction on the cooling steam pipe, the inlet of cooling steam pipe is connected with the steam extraction mouth of No. two steam turbine low pressure cylinders, first stop valve and first governing valve are installed in proper order along steam flow direction to the inlet of cooling steam pipe, the outlet of cooling steam pipe is connected with the inlet of No. one steam turbine low pressure cylinder, second governing valve and second stop valve are installed in proper order along steam flow direction to the outlet of cooling steam pipe, cooling water inlet and cooling water outlet of temperature reducing device are connected with cooling water inlet pipe and cooling water outlet pipe respectively.
Preferably, the pressure reducing device is provided with a first steam bypass, and a first gate valve, a second gate valve and a third gate valve are respectively installed on a steam inlet, a steam outlet and the first steam bypass of the pressure reducing device.
Preferably, the temperature reducing device is provided with a second steam bypass, and a fourth gate valve, a fifth gate valve and a sixth gate valve are respectively installed on the steam inlet, the steam outlet and the second steam bypass of the temperature reducing device.
Preferably, the steam parameter measuring device comprises a steam flow meter, a steam pressure meter and a steam temperature meter.
Preferably, the steam outlet of the steam parameter measuring device is connected with the steam extraction port of the first steam turbine low-pressure cylinder through a cooling steam branch pipe, and a third regulating valve and a third stop valve are sequentially arranged on the cooling steam branch pipe along the steam flow direction.
Preferably, the first regenerative system further comprises a first third low-pressure heater, a water inlet of the first third low-pressure heater is connected with a water outlet of the first second low-pressure heater, a steam inlet of the first third low-pressure heater is connected with a third steam extraction port of a first steam turbine low-pressure cylinder through a first third steam extraction pipe, and a ninth gate valve is arranged on the first third steam extraction pipe; the second regenerative system further comprises a second third low-pressure heater, a water inlet of the second third low-pressure heater is connected with a water outlet of the second low-pressure heater, and a steam inlet of the second third low-pressure heater is connected with a third steam extraction port of a second steam turbine low-pressure cylinder through a second third steam extraction pipe.
Preferably, the first back pressure butterfly valve is a valve without mechanical limit, and fluid is not leaked when the valve is fully closed; the first extraction condensation butterfly valve and the second extraction condensation butterfly valve are mechanically limited valves, and fluid can still circulate when the valves are fully closed.
Preferably, the steam inlet of the cooling steam pipe is connected with the second-stage steam extraction port of the low-pressure cylinder of the second steam turbine, and the cooling steam branch pipe is connected with the first-stage steam extraction port or the second-stage steam extraction port of the low-pressure cylinder of the first steam turbine.
Preferably, the steam inlet of the cooling steam pipe is connected with the second-stage steam extraction port or the third-stage steam extraction port of the low-pressure cylinder of the second steam turbine, and the cooling steam branch pipe is connected with the first-stage steam extraction port, the second-stage steam extraction port or the third-stage steam extraction port of the low-pressure cylinder of the first steam turbine.
The adjusting method of the condensing back heat supply system based on the two units is characterized by comprising the following steps of: the adjusting method comprises the following steps:
when the first cogeneration unit supplies heat for steam extraction working conditions: fully opening a first back pressure butterfly valve, adjusting the opening of the first extraction condensation butterfly valve, and enabling part of exhaust steam of a first turbine middle pressure cylinder to enter a first turbine low pressure cylinder through a first communicating pipe to continuously apply work; the other part of exhaust steam of the medium pressure cylinder of the first steam turbine supplies heat to the outside through a first heating steam extraction pipe; at this time, the first stop valve, the second stop valve and the third stop valve are closed, and the cooling steam system is not put into operation;
when the first cogeneration unit is in a back pressure heat supply working condition: closing the back pressure butterfly valve and the extraction condensation butterfly valve, wherein the exhaust steam of the middle pressure cylinder of the first turbine does not enter the low pressure cylinder of the first turbine to do work, but the exhaust steam of the middle pressure cylinder of the first turbine supplies heat to the outside through the heating extraction pipe; at the moment, the first stop valve and the second stop valve are opened, and the cooling steam system is put into operation; the second-stage extraction steam or the third-stage extraction steam from the second turbine low-pressure cylinder enters the first turbine low-pressure cylinder through a cooling steam pipe to cool the first turbine low-pressure cylinder; judging whether to start a cooling steam branch pipe according to whether cooling of a low-pressure cylinder of the first steam turbine is sufficient or not; when the temperature monitoring system of the first turbine low pressure cylinder shows that the temperature exceeds a safety value, a third stop valve is opened, and cooling steam enters the first turbine low pressure cylinder through a steam extraction port of the first turbine low pressure cylinder to fully cool the first turbine low pressure cylinder; when the temperature monitoring system of the first steam turbine low-pressure cylinder shows that the temperature is in a safe value range, the third stop valve is closed, and the cooling steam branch pipe is in a closed state; judging the opening degree of the first regulating valve according to the measured value of the steam parameter measuring device, so as to regulate the flow of cooling steam; secondly, judging whether the pressure reducing device is put into operation or not, so as to ensure that the pressure parameter of the cooling steam meets the requirement; thirdly, judging whether the temperature reducing device is put into operation or not, so that the temperature parameter of the cooling steam is ensured to meet the requirement; when the temperature reducing device is put into operation, the cooling water source of the temperature reducing device can be from condensation water, boiler water or low-temperature circulating water of the thermal power plant.
Compared with the prior art, the invention has the following advantages and positive effects: (1) The invention has reasonable design, simple structure and reliable performance, realizes the temperature reduction of the cooling steam through indirect heat exchange, and ensures the quality of the cooling steam; (2) According to the invention, the extraction steam of the low-pressure cylinder regenerative system of the turbine after acting is used as a steam source of cooling steam, so that irreversible loss caused by temperature and pressure reduction in the cooling steam system is reduced; (3) The invention combines the advantages of the thermal power plant that two units are arranged, ensures the reliability of a cooling steam source and improves the safety of the steam turbine in operation without entering the low-pressure cylinder.
Drawings
Fig. 1 is a schematic overall structure of the present embodiment.
Fig. 2 is a schematic structural diagram of a low-pressure cylinder of a first steam turbine in this embodiment, which is a two-stage regenerative extraction.
Fig. 3 is a schematic structural diagram of a two-stage regenerative extraction of low-pressure cylinder of a second turbine in this embodiment.
Fig. 4 is a schematic structural diagram of a third-stage regenerative extraction of low-pressure cylinder of a first turbine in this embodiment.
Fig. 5 is a schematic structural diagram of a third-stage regenerative extraction of low-pressure cylinder of a second turbine in this embodiment.
Detailed Description
The present invention will be described in further detail by way of examples with reference to the accompanying drawings, which are illustrative of the present invention and not limited to the following examples.
Referring to fig. 1, a condensation back heat supply system based on two units, a cogeneration unit includes: a first cogeneration unit, a second cogeneration unit and a cooling steam system.
The first cogeneration unit comprises: the steam turbine medium pressure cylinder 101, the steam turbine low pressure cylinder 102, the steam condenser 103, the condensate pump 104 and the regenerative system 11 are arranged, the steam outlet of the steam turbine medium pressure cylinder 101 is connected with the steam inlet of the steam turbine low pressure cylinder 102 through the communicating pipe 110, the back pressure butterfly valve 120 and the condensate pump butterfly valve 121 are sequentially arranged on the communicating pipe 110 along the steam flow direction, the steam turbine medium pressure cylinder 101 is connected with the heating steam extraction pipe 111, the steam outlet of the steam turbine low pressure cylinder 102 is connected with the steam condenser 103, and the steam condenser 103 is connected with the condensate pump 104.
The second cogeneration unit comprises: the steam turbine medium pressure cylinder 201, the steam turbine low pressure cylinder 202, the steam turbine condenser 203, the condensate pump 204 and the heat recovery system 12 are arranged, the steam outlet of the steam turbine medium pressure cylinder 201 is connected with the steam inlet of the steam turbine low pressure cylinder 202 through the communication pipe 210, the second extraction butterfly valve 220 is arranged on the communication pipe 210, the steam turbine medium pressure cylinder 201 is connected with the heating steam extraction pipe 211, the steam outlet of the steam turbine low pressure cylinder 202 is connected with the steam condenser 203, and the steam condenser 203 is connected with the condensate pump 204.
The cooling steam system includes: the cooling steam pipe 310, the pressure reducing device 301, the temperature reducing device 302 and the steam parameter measuring device 303 are sequentially installed on the cooling steam pipe 310 along the steam flow direction, the pressure reducing device 301, the temperature reducing device 302 and the steam parameter measuring device 303 are sequentially installed on the cooling steam pipe 310, the steam inlet of the cooling steam pipe 310 is connected with the steam outlet of the second steam turbine low pressure cylinder 202, the first stop valve 320 and the first regulating valve 321 are sequentially installed on the steam inlet of the cooling steam pipe 310 along the steam flow direction, the steam outlet of the cooling steam pipe 310 is connected with the steam inlet of the first steam turbine low pressure cylinder 102, the second regulating valve 329 and the second stop valve 328 are sequentially installed on the steam outlet of the cooling steam pipe 310 along the steam flow direction, the cooling water inlet and the cooling water outlet of the temperature reducing device 302 are respectively connected with the cooling water inlet pipe 313 and the cooling water outlet 314, the pressure reducing device 301 is provided with the first steam bypass 311, the first gate valve 322, the second gate valve 323 and the third gate valve 324 are respectively installed on the steam inlet of the pressure reducing device 301, the second gate valve 323 and the third gate valve 324 are respectively installed on the steam inlet of the second steam outlet of the pressure reducing device 302 and the fourth gate valve 312, and the fifth gate valve 327 are respectively installed on the steam outlet of the second steam bypass valve 326 and the fifth gate valve 312.
The steam parameter measuring device 303 comprises a steam flow measuring instrument, a steam pressure measuring instrument and a steam temperature measuring instrument, the steam outlet of the steam parameter measuring device 303 is connected with the steam outlet of the first steam turbine low pressure cylinder 102 through a cooling steam branch pipe 315, and a third regulating valve 331 and a third stop valve 330 are sequentially arranged on the cooling steam branch pipe 315 along the steam flow direction.
The first back pressure butterfly valve 120 is a valve without mechanical limitation, and fluid does not leak when the valve is fully closed; the first extraction butterfly valve 121 and the second extraction butterfly valve 220 are mechanically limited valves, and fluid can still circulate when the valves are fully closed.
Referring to fig. 2, the first regenerative system 11 includes: the first-stage low-pressure heater 105 and the second-stage low-pressure heater 106, the water inlet of the first-stage low-pressure heater 105 is connected with the water outlet of the first condensate pump 104, the steam inlet of the first-stage low-pressure heater 105 is connected with the first-stage steam outlet of the first turbine low-pressure cylinder 102 through the first-stage steam extraction pipe 112, the seventh gate valve 122 is arranged on the first-stage steam extraction pipe 112, the water inlet of the first-stage low-pressure heater 106 is connected with the water outlet of the first-stage low-pressure heater 105, the steam inlet of the first-stage low-pressure heater 106 is connected with the second-stage steam extraction port of the first turbine low-pressure cylinder 102 through the first-stage steam extraction pipe 113, and the eighth gate valve 123 is arranged on the first-stage second-stage steam extraction pipe 113.
Referring to fig. 3, the No. two regenerator system 12 includes: the water inlet of the second-stage low-pressure heater 205 is connected with the water outlet of the second condensate pump 204, the steam inlet of the second-stage low-pressure heater 205 is connected with the first-stage steam extraction port of the second turbine low-pressure cylinder 202 through a second-stage steam extraction pipe 212, the water inlet of the second-stage low-pressure heater 206 is connected with the water outlet of the second-stage low-pressure heater 205, and the steam inlet of the second-stage low-pressure heater 206 is connected with the second-stage steam extraction port of the second turbine low-pressure cylinder 202 through a second-stage steam extraction pipe 213.
Referring to fig. 1, 2 and 3, when the regenerative systems of the first turbine low pressure cylinder 102 and the second turbine low pressure cylinder 202 are two-stage regenerative, the steam inlet of the cooling steam pipe 310 is connected to the second steam extraction port of the second turbine low pressure cylinder 202, and the cooling steam branch pipe 315 is connected to the first steam extraction port or the second steam extraction port of the first turbine low pressure cylinder 102.
Referring to fig. 4, the first heat recovery system 11 further includes a first third low pressure heater 107, a water inlet of the first third low pressure heater 107 is connected to a water outlet of the first second low pressure heater 106, a steam inlet of the first third low pressure heater 107 is connected to a third steam extraction port of the first turbine low pressure cylinder 102 through a first third steam extraction pipe 114, and a ninth gate valve 124 is installed on the first third steam extraction pipe 114.
Referring to fig. 5, the second heat recovery system 12 further includes a second three-stage low-pressure heater 207, a water inlet of the second three-stage low-pressure heater 207 is connected to a water outlet of the second two-stage low-pressure heater 206, and a steam inlet of the second three-stage low-pressure heater 207 is connected to a three-stage steam extraction port of the second turbine low-pressure cylinder 202 through a second three-stage steam extraction pipe 214.
Referring to fig. 1, 4 and 5, when the regenerator systems of the first turbine low pressure cylinder 102 and the second turbine low pressure cylinder 202 are three-stage regenerations, the steam inlet of the cooling steam pipe 310 is connected to the second steam extraction port or the third steam extraction port of the second turbine low pressure cylinder 202, and the cooling steam branch pipe 315 is connected to the first steam extraction port, the second steam extraction port or the third steam extraction port of the first turbine low pressure cylinder 102.
The adjusting method of the condensing back heat supply system based on the two units comprises the following steps:
when the first cogeneration unit is in the working condition of steam extraction and heat supply,
fully opening a first back pressure butterfly valve 120, adjusting the opening of a first extraction condensation butterfly valve 121, and enabling part of exhaust steam of a first turbine middle pressure cylinder 101 to enter a first turbine low pressure cylinder 102 through a first communicating pipe 110 to continuously do work; the other part of exhaust steam of the medium pressure cylinder 101 of the first steam turbine supplies heat to the outside through a first heating steam extraction pipe 111;
at this time, the first stop valve 320, the second stop valve 328, and the third stop valve 330 are closed, and the cooling steam system is not put into operation.
When the first cogeneration unit is in the back pressure heat supply working condition,
the back pressure butterfly valve 120 and the extraction condensation butterfly valve 121 are fully closed, and the exhaust steam of the middle pressure cylinder 101 of the first steam turbine does not enter the low pressure cylinder 102 of the first steam turbine to do work any more, but all the exhaust steam of the middle pressure cylinder 101 of the first steam turbine supplies heat to the outside through the heating steam extraction pipe 111;
at this time, the first shut-off valve 320 and the second shut-off valve 328 are opened, and the cooling steam system is put into operation;
at this time, the second extraction steam or the third extraction steam from the second turbine low pressure cylinder 202 enters the first turbine low pressure cylinder 102 through the cooling steam pipe 310 to cool the first turbine low pressure cylinder 102;
at this time, whether to open the cooling steam manifold 315 is determined based on whether cooling of the first turbine low pressure cylinder 102 is sufficient; when the temperature monitoring system of the first turbine low pressure cylinder 102 shows that the temperature exceeds a safety value, the third stop valve 330 is opened, and cooling steam also enters the first turbine low pressure cylinder 102 through a steam extraction port of the first turbine low pressure cylinder 102 to fully cool the first turbine low pressure cylinder 102; when the temperature monitoring system of the first turbine low pressure cylinder 102 shows that the temperature is within the safe value range, the third stop valve 330 is closed, and the cooling steam branch pipe 315 is in a closed state;
at this time, according to the measured value of the steam parameter measuring device 303, firstly, the opening degree of the first regulating valve 321 is judged, so that the flow rate of the cooling steam is regulated; secondly, whether the pressure reducing device 301 is put into operation is judged, so that the pressure parameter of the cooling steam is ensured to meet the requirement; thirdly, judging whether the temperature reducing device 302 is put into operation or not, so as to ensure that the temperature parameter of the cooling steam meets the requirement; when the attemperator 302 is put into operation, the cooling water source of the attemperator 302 may be from condensate, boiler make-up, or low-temperature circulating water from a thermal power plant.
In addition, it should be noted that the specific embodiments described in the present specification may vary from part to part, from name to name, etc., and the above description in the present specification is merely illustrative of the structure of the present invention. Equivalent or simple changes of the structure, characteristics and principle of the present invention are included in the protection scope of the present invention. Those skilled in the art may make various modifications or additions to the described embodiments or substitutions in a similar manner without departing from the scope of the invention as defined in the accompanying claims.
Claims (7)
1. The condensing back-pumping heat supply system based on the two units comprises a first cogeneration unit, a second cogeneration unit and a cooling steam system; the method is characterized in that:
the first cogeneration unit comprises: a first turbine intermediate pressure cylinder (101), a first turbine low pressure cylinder (102), a first condenser (103), a first condensate pump (104) and a first heat recovery system (11); the steam turbine low-pressure cylinder comprises a first steam turbine medium-pressure cylinder (101), a first back pressure butterfly valve (120) and a first condensation butterfly valve (121) which are sequentially arranged on a first communicating pipe (110) along the steam flow direction, wherein a first heating steam extraction pipe (111) is connected to the first steam turbine medium-pressure cylinder (101), the steam outlet of the first steam turbine low-pressure cylinder (102) is connected with a first condenser (103), and the first condenser (103) is connected with a first condensation water pump (104); the first heat recovery system (11) comprises: the system comprises a first-stage low-pressure heater (105) and a first-stage second-pressure heater (106), wherein a water inlet of the first-stage low-pressure heater (105) is connected with a water outlet of a first condensate pump (104), a steam inlet of the first-stage low-pressure heater (105) is connected with a first-stage steam extraction port of a first turbine low-pressure cylinder (102) through a first-stage steam extraction pipe (112), a seventh gate valve (122) is arranged on the first-stage steam extraction pipe (112), a water inlet of the first-stage second-pressure heater (106) is connected with a water outlet of the first-stage low-pressure heater (105), a steam inlet of the first-stage second-pressure heater (106) is connected with a second-stage steam extraction port of the first turbine low-pressure cylinder (102) through a first-stage second-stage steam extraction pipe (113), and an eighth gate valve (123) is arranged on the first-stage second-stage steam extraction pipe (113);
the second cogeneration unit comprises: a second turbine intermediate pressure cylinder (201), a second turbine low pressure cylinder (202), a second condenser (203), a second condensate pump (204) and a second regenerative system (12); the exhaust port of the second turbine intermediate pressure cylinder (201) is connected with the steam inlet of the second turbine low pressure cylinder (202) through a second communicating pipe (210), a second condensation extraction butterfly valve (220) is arranged on the second communicating pipe (210), the second turbine intermediate pressure cylinder (201) is connected with a second heating steam extraction pipe (211), the steam outlet of the second turbine low pressure cylinder (202) is connected with a second condenser (203), and the second condenser (203) is connected with a second condensation water pump (204); the second regenerative system (12) comprises: the system comprises a second-stage low-pressure heater (205) and a second-stage low-pressure heater (206), wherein a water inlet of the second-stage low-pressure heater (205) is connected with a water outlet of a second condensate pump (204), a steam inlet of the second-stage low-pressure heater (205) is connected with a first-stage steam extraction port of a second turbine low-pressure cylinder (202) through a second-stage steam extraction pipe (212), a water inlet of the second-stage low-pressure heater (206) is connected with a water outlet of the second-stage low-pressure heater (205), and a steam inlet of the second-stage low-pressure heater (206) is connected with a second-stage steam extraction port of the second turbine low-pressure cylinder (202) through a second-stage steam extraction pipe (213);
the cooling steam system includes: a cooling steam pipe (310), a pressure reducing device (301), a temperature reducing device (302) and a steam parameter measuring device (303); the cooling steam pipe (310) is sequentially provided with a pressure reducing device (301), a temperature reducing device (302) and a steam parameter measuring device (303) along the steam flow direction, a steam inlet of the cooling steam pipe (310) is connected with a steam extraction port of a low-pressure cylinder (202) of a second steam turbine, a first stop valve (320) and a first regulating valve (321) are sequentially arranged at the steam inlet of the cooling steam pipe (310) along the steam flow direction, a steam outlet of the cooling steam pipe (310) is connected with a steam inlet of a low-pressure cylinder (102) of the first steam turbine, a second regulating valve (329) and a second stop valve (328) are sequentially arranged at the steam outlet of the cooling steam pipe (310) along the steam flow direction, and a cooling water inlet and a cooling water outlet of the temperature reducing device (302) are respectively connected with a cooling water inlet pipe (313) and a cooling water outlet pipe (314);
the pressure reducing device (301) is provided with a first steam bypass (311), and a first gate valve (322), a second gate valve (323) and a third gate valve (324) are respectively arranged on a steam inlet, a steam outlet and the first steam bypass (311) of the pressure reducing device (301); the temperature reducing device (302) is provided with a second steam bypass (312), and a fourth gate valve (325), a fifth gate valve (326) and a sixth gate valve (327) are respectively arranged on a steam inlet, a steam outlet and the second steam bypass (312) of the temperature reducing device (302);
the steam outlet of the steam parameter measuring device (303) is connected with the steam extraction port of the first steam turbine low-pressure cylinder (102) through a cooling steam branch pipe (315), and a third regulating valve (331) and a third stop valve (330) are sequentially arranged on the cooling steam branch pipe (315) along the steam flow direction.
2. The two-unit-based back-to-back heat supply system of claim 1, wherein: the steam parameter measuring device (303) comprises a steam flow measuring instrument, a steam pressure measuring instrument and a steam temperature measuring instrument.
3. The two-unit-based back-to-back heat supply system of claim 1, wherein: the first heat recovery system (11) further comprises a first three-level low-pressure heater (107), a water inlet of the first three-level low-pressure heater (107) is connected with a water outlet of a first second low-pressure heater (106), a steam inlet of the first three-level low-pressure heater (107) is connected with a three-level steam extraction port of a first steam turbine low-pressure cylinder (102) through a first three-level steam extraction pipe (114), and a ninth gate valve (124) is arranged on the first three-level steam extraction pipe (114); the second regenerative system (12) further comprises a second third low-pressure heater (207), a water inlet of the second third low-pressure heater (207) is connected with a water outlet of the second low-pressure heater (206), and a steam inlet of the second third low-pressure heater (207) is connected with a third steam extraction port of a second steam turbine low-pressure cylinder (202) through a second third steam extraction pipe (214).
4. The two-unit-based back-to-back heat supply system of claim 1, wherein: the first back pressure butterfly valve (120) is a valve without mechanical limit; the first extraction and condensation butterfly valve (121) and the second extraction and condensation butterfly valve (220) are valves with mechanical limit.
5. The two-unit-based back-to-back heat supply system of claim 1, wherein: the steam inlet of the cooling steam pipe (310) is connected with the second-stage steam extraction port of the low-pressure cylinder (202) of the No. two steam turbines, and the cooling steam branch pipe (315) is connected with the first-stage steam extraction port or the second-stage steam extraction port of the low-pressure cylinder (102) of the No. one steam turbines.
6. A two-unit based back heat pump heating system according to claim 3, wherein: the steam inlet of the cooling steam pipe (310) is connected with the second-stage steam extraction port or the third-stage steam extraction port of the second-stage turbine low-pressure cylinder (202), and the cooling steam branch pipe (315) is connected with the first-stage steam extraction port, the second-stage steam extraction port or the third-stage steam extraction port of the first-stage turbine low-pressure cylinder (102).
7. A method of regulating a two-unit based on-set back heat supply system according to any one of claims 1 to 6, characterized in that: the adjusting method comprises the following steps:
when the first cogeneration unit supplies heat for steam extraction working conditions: fully opening a first back pressure butterfly valve (120), adjusting the opening of a first extraction condensation butterfly valve (121), and enabling part of exhaust steam of a first turbine medium pressure cylinder (101) to enter a first turbine low pressure cylinder (102) through a first communicating pipe (110) to continuously apply work; the other part of exhaust steam of the medium pressure cylinder (101) of the first steam turbine supplies heat to the outside through a first heating steam extraction pipe (111); at this time, the first stop valve (320), the second stop valve (328), and the third stop valve (330) are closed, and the cooling steam system is not put into operation;
when the first cogeneration unit is in a back pressure heat supply working condition: the exhaust steam of the middle pressure cylinder (101) of the first steam turbine is externally supplied with heat through a first heating steam extraction pipe (111); at this time, the first stop valve (320) and the second stop valve (328) are opened, and the cooling steam system is put into operation; the second-stage extraction steam or the third-stage extraction steam from the second turbine low-pressure cylinder (202) enters the first turbine low-pressure cylinder (102) through a cooling steam pipe (310) to cool the first turbine low-pressure cylinder (102); judging whether to open a cooling steam branch pipe (315) according to whether cooling of the first turbine low pressure cylinder (102) is sufficient; when the temperature monitoring system of the first turbine low pressure cylinder (102) shows that the temperature exceeds a safety value, a third stop valve (330) is opened, cooling steam also enters the first turbine low pressure cylinder (102) through a steam extraction port of the first turbine low pressure cylinder (102), and the first turbine low pressure cylinder (102) is fully cooled; when the temperature monitoring system of the low-pressure cylinder (102) of the first steam turbine shows that the temperature is in a safe value range, the third stop valve (330) is closed, and the cooling steam branch pipe (315) is in a closed state; firstly, judging the opening degree of a first regulating valve (321) according to the measured value of a steam parameter measuring device (303), so as to regulate the flow rate of cooling steam; secondly, judging whether the pressure reducing device (301) is put into operation, so as to ensure that the pressure parameter of the cooling steam meets the requirement; thirdly, judging whether the temperature reducing device (302) is put into operation, so as to ensure that the temperature parameter of the cooling steam meets the requirement; when the temperature reducing device (302) is put into operation, the cooling water source of the temperature reducing device (302) is from condensate water, boiler make-up water or low-temperature circulating water of the thermal power plant.
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| CN108999653B (en) * | 2018-08-16 | 2023-07-18 | 华电电力科学研究院有限公司 | Shaft seal device for adjustable extraction steam turbine and working method of shaft seal device |
| CN109441570B (en) * | 2018-11-05 | 2023-09-05 | 华电电力科学研究院有限公司 | Condensation back-pumping heat supply system for combination of two units and operation method |
| CN109611166B (en) * | 2018-11-20 | 2023-09-05 | 华电电力科学研究院有限公司 | Condensing back-pumping heat supply system for variable working conditions of multi-low pressure cylinder steam turbine and operation method |
| CN109404073B (en) * | 2018-11-20 | 2023-09-15 | 华电电力科学研究院有限公司 | Condensation back-pumping heat supply system for variable working condition unit and operation method |
| CN109779699B (en) * | 2019-02-02 | 2023-09-05 | 华电电力科学研究院有限公司 | High-efficiency energy-saving quick starting system of steam turbine generator unit and operation method thereof |
| CN110566295B (en) * | 2019-07-27 | 2021-11-26 | 华电电力科学研究院有限公司 | Double-unit coupling peak shaving method and device based on power plant electricity and heat load cooperative scheduling |
| CN113153454A (en) * | 2021-03-15 | 2021-07-23 | 威立雅（哈尔滨）热电有限公司 | Anticorrosive drying device in combined heat and power generation steam turbine summer |
| CN114704340B (en) * | 2022-05-06 | 2023-12-08 | 中国船舶重工集团公司第七0三研究所 | Double-low-pressure cylinder zero-output steam turbine unit regenerative system and operation method |
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| CN106194296A (en) * | 2016-09-05 | 2016-12-07 | 华能国际电力股份有限公司 | A kind of thermoelectricity decoupling heating system from station boiler steam pumping |
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