CN114439559B - Heat supply method for switching condensing type and high back pressure of steam turbine generator set - Google Patents

Heat supply method for switching condensing type and high back pressure of steam turbine generator set Download PDF

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Publication number
CN114439559B
CN114439559B CN202111498560.0A CN202111498560A CN114439559B CN 114439559 B CN114439559 B CN 114439559B CN 202111498560 A CN202111498560 A CN 202111498560A CN 114439559 B CN114439559 B CN 114439559B
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steam
pressure cylinder
pressure
low
heat supply
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CN114439559A (en
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文立斌
胡弘
李俊
孙志媛
吴健旭
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Electric Power Research Institute of Guangxi Power Grid Co Ltd
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Electric Power Research Institute of Guangxi Power Grid Co Ltd
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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
    • 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
    • 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
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
    • F22B33/00—Steam-generation plants, e.g. comprising steam boilers of different types in mutual association
    • F22B33/18—Combinations of steam boilers with other apparatus

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Control Of Turbines (AREA)

Abstract

The invention relates to the technical fields of heat supply, power generation and control analysis thereof, in particular to a heat supply method for switching condensing type and high back pressure of a turbine generator set. The invention adopts the change-over switch module to realize the mutual change-over operation of the heat supply steam turbine generator unit under two different working conditions of condensing type and high back pressure, the low pressure cylinder can completely cut off zero output through the change-over control module, the output of the generator can be increased at any time, the dependency relationship between the heat supply and the power generation of the unit is reduced, and the comprehensive energy utilization efficiency is improved. The high back pressure working condition operation is carried out when the heat supply steam quantity is large, the condensing working condition operation is carried out when the heat supply steam quantity is small or no steam supply is carried out and the high power of the generator is required, the quick response and regulation when the heat supply steam quantity or the power generation power is greatly changed are met, and the auxiliary service capacities of the unit in power grid peak regulation, frequency modulation and the like are improved.

Description

Heat supply method for switching condensing type and high back pressure of steam turbine generator set
Technical Field
The invention relates to the technical fields of heat supply, power generation and control analysis thereof, in particular to a heat supply method for switching condensing type and high back pressure of a turbine generator set.
Background
In order to relieve the related contradiction of thermoelectric strength of the cogeneration unit, improve the running flexibility of the unit, and develop the zero-output technical transformation and application of the low-pressure cylinder of the steam turbine in recent years. Chen Jianguo et al in 300 MW units steam turbine low pressure cylinder zero output technology, from the low pressure cylinder zero output operation low pressure cylinder final stage blade safety consideration, working out the perfect low pressure cylinder operation monitoring measuring point, final stage blade metal spraying, setting low pressure through flow cooling steam system and maintaining low pressure cylinder high vacuum technical measures; liu Qijun application of the low-pressure cylinder zero-output technology to a condensing heat supply unit introduces the key technology of low-pressure cylinder zero-output modification, namely modification of a low-pressure cylinder operation monitoring system, a low-pressure cylinder water spraying system, a low-pressure cylinder cooling steam system and a thermodynamic system, and analyzes the influence of the low-pressure cylinder zero-output modification on the safety of a steam turbine. From the published literature, various corresponding technical measures are adopted from the safety of the last stage blade of the low-pressure cylinder, the unit is still in a condensing type running state, the low-pressure cylinder cannot be completely cut off and run, the rotor of the low-pressure cylinder, the rotor of the steam turbine and the rotor of the generator run synchronously at 3000r/min, and a small amount of steam needs to be continuously flowed to cool the last stage blade of the low-pressure cylinder to prevent over-temperature damage. The adopted low-pressure cylinder zero-output technical measure relates to a plurality of devices, complex process and long construction period; the rotor of the low-pressure cylinder continuously runs at high speed for a long time under the condition of small steam flow of the low-pressure cylinder, and the service lives of the low-pressure cylinder and the rotor of the low-pressure cylinder are influenced; when the unit supplies heat, the unit is in a condensing type running state, a large amount of circulating water is needed, and a large amount of heat loss of steam turbine exhaust steam is caused; the electric power regulation range of the unit is small under the influence of 'electricity fixed by heat', and the unit is difficult to participate in auxiliary services such as peak regulation, frequency modulation and the like of a power grid. In order to solve the problem of the technology adopted by the low-pressure cylinder zero output, the invention provides a heat supply method for switching the condensing type of a steam turbine generator set and high back pressure.
Disclosure of Invention
In order to solve the problems, the invention provides a heat supply method for switching between condensing type and high back pressure of a steam turbine generator set, which comprises the following specific technical scheme:
a heat supply method for switching condensing type and high back pressure of a turbine generator set comprises a boiler, a high-pressure cylinder, a medium-pressure cylinder, a generator and a low-pressure cylinder; the method comprises the following steps:
s1: the boiler is respectively connected with a high-pressure cylinder and a medium-pressure cylinder; connecting the medium-voltage cylinder with a generator; the generator is connected with the low-voltage cylinder through a change-over switch module; the middle pressure cylinder is connected with the low pressure cylinder through a middle and low pressure cylinder communication pipe; the middle-low pressure cylinder communication pipe is connected with the heat supply steam header through the heat supply steam main pipe, so that external heat supply is realized;
s2: when the change-over switch module is disconnected, the generator is disconnected with the low-pressure cylinder, the low-pressure cylinder is cut off for operation, and the turbine generator set operates under a high back pressure working condition and supplies heat to the outside;
s3: when the change-over switch module is closed, the generator is connected with the low-pressure cylinder, the low-pressure cylinder is put into operation, and the turbine generator set operates under a condensing type working condition and supplies heat to the outside.
Preferably, the change-over switch module realizes the change-over of the operation condition of the steam turbine generator set by means of gear engagement and separation.
Preferably, the change-over switch module comprises a gear box control module, a gear driving motor and a gear box; a generator end gear, a low-pressure cylinder end gear, a generator end transmission gear and a low-pressure cylinder end transmission gear are arranged in the gear box; the generator end gear is connected with a generator; the low-pressure cylinder end gear is connected with the low-pressure cylinder; the generator end transmission gear is rigidly connected with the low-pressure cylinder end transmission gear through a transmission shaft; the generator end transmission gear is sleeved on the bearing; the gear box control module is connected with the gear driving motor; an output shaft of the gear driving motor is connected with a bearing; the generator and the low-pressure cylinder are arranged on the same axis center line;
the gear box control module sends out a separated control signal, the gear drive motor drives the generator end transmission gear to translate leftwards or rightwards, the generator end transmission gear is separated from the generator end gear, the low-pressure cylinder end transmission gear is separated from the low-pressure cylinder end gear, and then the low-pressure cylinder cutting operation is realized.
Preferably, the operation of the turbine generator set under the high back pressure working condition in the step S2 is specifically:
the rotor of the turbo generator set is in a low-speed jigger state, the low-pressure cylinder is cut off and operated, and each valve is kept in a closed state;
The method comprises the steps of supplying steam by a shaft seal of a steam turbine, starting a vacuum pump, starting a circulating water inlet regulating valve, and enabling circulating water to enter a condenser through a circulating water inlet pipe for cooling; when the display value of the condenser pressure measuring device is not higher than P 0 When the high-pressure bypass valve of the steam turbine and the temperature reducing device thereof are opened, the low-pressure bypass valve of the steam turbine and the temperature reducing device thereof are matched with the boiler to adjust the outlet steam of the boilerSteam parameters, the steam parameters of the outlet of the boiler are improved to meet the requirement of turbine flushing;
the full-open high-pressure cylinder vacuumizing valve is used for closing the low-pressure bypass valve of the turbine and the temperature reducing device thereof, opening the high-pressure regulating valve and the medium-pressure regulating valve to flush the turbine, reaching the rated rotation speed of the generator, and opening the high-pressure regulating valve to the minimum allowable opening CV 0 The rotation speed of the steam turbine is controlled by the medium-pressure regulating valve, and high-pressure cylinder through-flow steam enters the condenser through the high-pressure cylinder vacuumizing valve and the high-pressure cylinder vacuumizing steam exhaust pipe; the steam pressure in the communication pipe of the middle and low pressure cylinders exceeds the starting value of the safety valve by 1.2P Feed device The rear safety valve is opened, the medium-pressure cylinder discharges steam to the atmosphere through the safety valve, and the heating steam regulating valve can be opened to supply steam outwards through the heating steam main pipe and the heating steam header; along with the increase of the steam supply, the steam pressure in the communication pipe of the middle and low pressure cylinders is gradually reduced by Zhe and is lower than the closing value of the safety valve by 0.95P Feed device The back safety valve seat is closed, the steam supply is controlled by the opening degree of the medium pressure regulating valve, the power of the generator is determined by the flow steam quantity of the medium pressure cylinder, and the maximum value of the power of the generator is not more than 30% P N ，P N Rated power for the turbine unit.
Preferably, in the step S3, the operation of the steam turbine generator set under the condensing working condition specifically includes:
the rotor of the turbo generator set is in a low-speed turning state, the low-pressure cylinder is put into operation, and each valve is kept in a closed state;
starting a circulating water inlet regulating valve, supplying steam to a shaft seal of a steam turbine, starting a vacuum pump, and starting the circulating water inlet regulating valve, wherein circulating water enters a condenser through a circulating water inlet pipe for cooling; the display value of the condenser pressure measuring device is not higher than P 0 When the high-pressure bypass valve and the temperature reducing device thereof of the steam turbine and the low-pressure bypass valve and the temperature reducing device thereof of the steam turbine are matched with the boiler to adjust steam parameters to put into operation, the steam parameters at the outlet of the boiler are improved to meet the flushing requirement of the steam turbine, and the butterfly valve of the communication pipe of the full-open middle-low pressure cylinder is opened;
the full-open high-pressure cylinder vacuumizing valve, the low-pressure bypass valve of the turbine and the temperature reducing device thereof are closed, the high-pressure regulating valve and the medium-pressure regulating valve are opened to flush the turbine,the rated rotation of the generator is achieved, and the high-pressure regulating valve is opened to the minimum allowable opening CV 0 The rotation speed of the steam turbine is controlled by the medium-pressure regulating valve, and high-pressure cylinder through-flow steam enters the condenser through the high-pressure cylinder vacuumizing valve and the high-pressure cylinder vacuumizing steam exhaust pipe; the rotation speeds of the turbine and the generator rotor reach rated rotation speeds and are stabilized and then grid-connected for power generation; when the power of the generator reaches 30% P N When the high-pressure regulating valve is opened, the high-pressure bypass valve of the steam turbine and the temperature reducing device thereof are closed until the high-pressure bypass valve is completely closed; when the power of the generated electricity reaches 40 percent P N When the vacuum valve of the high-pressure cylinder is closed, the steam exhaust check valve of the high-pressure cylinder is opened; the opening degree of the high-pressure regulating valve controls the power of the generator;
in the running process of the unit, the front steam pressure of the butterfly valve of the communication pipe of the middle and low pressure cylinder is controlled by adjusting the size of the butterfly valve of the communication pipe of the middle and low pressure cylinder, and steam is supplied to the outside through the main pipe of the heat supply steam and the heat supply steam header by opening the heat supply steam adjusting valve.
Preferably, the operation mode of the turbine generator set switched from the pure condensing mode to the high back pressure working condition is specifically as follows:
the turbine generator set is in pure condensing working condition operation, along with increasing the opening of the heat supply steam regulating valve, the heat supply steam flow is increased outwards through the heat supply steam main pipe and the heat supply steam header, the butterfly valve of the medium-low pressure cylinder communicating pipe is gradually turned off until the butterfly valve is fully turned off, the switching switch module is turned off, the low pressure cylinder is cut off to operate, and the turbine generator set is switched into a high back pressure working condition operation mode from the pure condensing working condition.
Preferably, the operation mode of switching the turbine generator set from high back pressure to pure condensing type or condensing type steam extraction and heat supply working conditions is specifically as follows:
the turbine generator set is operated under a high back pressure working condition; the low-pressure cylinder shaft seal supplies steam, a vacuum pump is started, a circulating water inlet regulating valve is opened, and circulating water enters a condenser through a circulating water inlet pipe for cooling; the display value of the condenser pressure measuring device is not higher than P 0 When the rotating speed of the low-pressure cylinder reaches a set value, a change-over switch module is closed, the low-pressure cylinder is put into operation, and at the moment, the turbine generator set is switched from a high back pressure working condition to pure condensationA steam-type working condition operation mode;
after the steam turbine generator set is switched to operate under a pure condensing working condition, the opening of a butterfly valve of a communication pipe of the middle and low pressure cylinders is increased to control the steam exhaust temperature of the low pressure cylinders to be less than 65 ℃; when no steam is supplied, the unit is in a pure condensing type working condition for operation; if the steam is required to be supplied, the steam can be supplied to the outside through the main pipe of the steam supply and the header of the steam supply by opening the steam supply regulating valve, and the unit is in the working condition of condensing type steam extraction and heat supply.
Preferably, the condition that the turbine generator set is switched from the pure condensing mode to the high back pressure working condition is as follows:
(1) The butterfly valve of the communication pipe of the middle and low pressure cylinders is completely closed;
(2) The opening of the high-pressure regulating valve is not smaller than the minimum allowable opening CV 0 。
Preferably, the condition that the steam turbine generator set is switched from high back pressure to pure condensing type or condensing type steam extraction and heat supply working conditions is as follows:
(1) The display value of the condenser pressure measuring device is not higher than P 0 ；
(2) The opening of the high-pressure regulating valve is not smaller than the minimum allowable opening CV 0 。
The beneficial effects of the invention are as follows: the invention adopts the change-over switch module to realize the mutual change-over operation of the heat supply steam turbine generator unit under two different working conditions of condensing type and high back pressure, the low pressure cylinder can completely cut off zero output through the change-over control module, the output of the generator can be increased at any time, the dependency relationship between the heat supply and the power generation of the unit is reduced, and the comprehensive energy utilization efficiency is improved. The high back pressure working condition operation is carried out when the heat supply steam quantity is large, the condensing working condition operation is carried out when the heat supply steam quantity is small or no steam supply is carried out and the high power of the generator is required, the quick response and regulation when the heat supply steam quantity or the power generation power is greatly changed are met, and the auxiliary service capacities of the unit in power grid peak regulation, frequency modulation and the like are improved.
According to the invention, the input or the cutting of the low-pressure cylinder is controlled through the engagement and the separation of the gears in the gear box, so that the complete cutting of the low-pressure cylinder is facilitated.
The gear ratio of gears in the gear box is adjusted, so that the low-pressure cylinder rotor runs at half speed or lower than half speed, the blast heat generated by the low-pressure cylinder rotor is obviously reduced, the risk of over-temperature damage of the last stage blade of the low-pressure cylinder is reduced, and the low-pressure cylinder rotor is suitable for long-term running under the working condition of low or no through flow of steam of the low-pressure cylinder; the steam turbine generator unit can fully utilize heat loss of steam turbine exhaust when operating under a high back pressure working condition, so that the consumption of circulating water is greatly reduced; and when the condenser runs under long-term high back pressure, the circulating water inlet regulating valve can be closed to stop circulating water cooling, the vacuum pump is closed to stop vacuumizing, the energy consumption of auxiliary equipment of the power plant is reduced, and the economic benefit level of the power plant is improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. Like elements or portions are generally identified by like reference numerals throughout the several figures. In the drawings, elements or portions thereof are not necessarily drawn to scale.
FIG. 1 is a schematic flow chart of the present invention;
FIG. 2 is a control schematic diagram of the present invention;
the high-pressure cylinder 1, the medium-pressure cylinder 2, the generator 3, the generator end gear 4, the gear box 5, the low-pressure cylinder end gear 6, the bearing 7, the generator end transmission gear 8, the transmission shaft 9, the low-pressure cylinder end transmission gear 10, the low-pressure cylinder 11, the low-pressure cylinder exhaust steam temperature measuring device 12, the condenser pressure measuring device 13, the circulating water outlet pipe 14, the circulating water inlet regulating valve 15, the circulating water inlet pipe 16, the condenser 17, the vacuum pump 18, the vacuum pump exhaust check valve 19, the vacuum pump exhaust pipe 20, the high-pressure cylinder vacuumizing exhaust pipe 21, the high-pressure cylinder vacuumizing valve 22, the high-pressure cylinder exhaust check valve 23, the boiler 24, the turbine high-pressure bypass valve 25, the high-pressure regulating valve 26, the medium-pressure regulating valve 27, the safety valve 28, the gear driving motor 29, the gear box communication cable 30, the gear box control module 31, the low-pressure cylinder rotating speed measuring device 32, the medium-low-pressure cylinder communicating pipe front steam pressure measuring device 33, the medium-low-pressure cylinder communicating pipe front steam temperature measuring device 34, the medium-low-pressure cylinder communicating pipe 35, the medium-pressure low-pressure communicating pipe 36, the medium-pressure and the butterfly valve heat supply valve 40, the butterfly valve and the low-pressure regulating valve heat supply device and the butterfly valve heat supply valve and the low-pressure regulating device.
Description of the embodiments
The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
It should be understood that the terms "comprises" and "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
It is also to be understood that the terminology used in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in this specification and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.
It should be further understood that the term "and/or" as used in the present specification and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes such combinations.
As shown in fig. 1, the specific embodiment of the invention provides a heat supply method for switching condensing type and high back pressure of a turbine generator set, wherein the turbine generator set comprises a boiler 24, a high-pressure cylinder 1, a medium-pressure cylinder 2, a generator 3 and a low-pressure cylinder 11;
the method comprises the following steps:
s1: connecting pipeline and valve: the boiler 24 is respectively connected with the high pressure cylinder 1 and the medium pressure cylinder 2; connecting the medium-voltage cylinder 2 with a generator 3; the generator 3 is connected with the low-voltage cylinder 11 through a change-over switch module; the middle pressure cylinder 2 is connected with the low pressure cylinder 11 through a middle and low pressure cylinder communication pipe 35; the middle and low pressure cylinder communication pipe 35 is connected with a heat supply steam header 40 through a heat supply steam main pipe 39 to realize external heat supply; a heating steam regulating valve 38 is arranged on the heating steam main pipe 39; the hot steam regulating valve 38 is used for regulating the steam flow provided by the intermediate pressure cylinder 2 to the heating steam header 40;
a middle-low pressure cylinder communication pipe butterfly valve 36 is arranged on the middle-low pressure cylinder communication pipe 35 between the joint of the middle-low pressure cylinder communication pipe 35 and the heat supply steam main pipe 39 and the low pressure cylinder 11; the middle-low pressure cylinder communicating pipe butterfly valve 36 is used for adjusting the steam flow of the steam discharged by the middle pressure cylinder 2 into the low pressure cylinder 11;
The heating steam regulating valve 38 and the middle-low pressure cylinder communication pipe butterfly valve 36 are respectively connected with a control device, and the control device is used for controlling the opening degree of the heating steam regulating valve 38 and the middle-low pressure cylinder communication pipe butterfly valve 36 and controlling the change-over switch module to change the running working state of the steam turbine generator set.
The switching switch module realizes the switching of the operation working conditions of the steam turbine generator set in a gear meshing and separating mode. The change-over switch module comprises a gear box control module 31, a gear driving motor 29 and a gear box 5; a generator end gear 4, a low-pressure cylinder end gear 6, a generator end transmission gear 8 and a low-pressure cylinder end transmission gear 10 are arranged in the gear box 5; the generator end gear 4 is connected with the generator 3; the low-pressure cylinder end gear 6 is connected with a low-pressure cylinder 11; the generator end transmission gear 8 is rigidly connected with the low-pressure cylinder end transmission gear 10 through a transmission shaft 9; the generator end transmission gear 8 is sleeved on the bearing 7; the gear box control module 31 is connected with the gear drive motor 29; an output shaft of the gear drive motor 29 is connected with the bearing 7; the generator 3 and the low-pressure cylinder 11 are on the same axis center line;
the gear box control module 31 sends out a separated control signal according to the control device, and controls the gear driving motor 29 to drive the generator end transmission gear 8 to translate leftwards or rightwards, so that the generator end transmission gear 8 is separated from the generator end gear 4, the low-pressure cylinder end transmission gear 10 is separated from the low-pressure cylinder end gear 6, and further the low-pressure cylinder 11 is cut off. The gear ratio of the generator end transmission gear 8 to the generator end gear 4 is 1:1; the gear ratio of the low-pressure cylinder end transmission gear 10 to the low-pressure cylinder end gear 6 is less than or equal to 1:2. Through the 'meshing' operation, the gear driving motor 29 drives the generator end transmission gear 8 to translate leftwards or rightwards, so that the engagement of the generator end transmission gear 8 and the generator end gear 4 is realized, the engagement of the low-pressure cylinder end transmission gear 10 and the low-pressure cylinder end gear 6 is realized, and the low-pressure cylinder 11 is further realized to be put into operation.
Through the separation operation, the gear driving motor 29 drives the generator end transmission gear 8 to translate leftwards or rightwards, so that the separation of the generator end transmission gear 8 and the generator end gear 4 is realized, and the separation of the low-pressure cylinder end transmission gear 10 and the low-pressure cylinder end gear 6 is realized; thereby realizing the cutting operation of the low pressure cylinder 11.
A front steam pressure measuring device 33 of a butterfly valve of the middle and low pressure cylinder communication pipe and a front steam temperature measuring device 34 of the butterfly valve of the middle and low pressure cylinder communication pipe are arranged in front of the joint of the middle and low pressure cylinder communication pipe 35 and the heat supply steam main pipe 39 and on the middle and low pressure cylinder communication pipe 35; the front steam pressure measuring device 33 of the middle-low pressure cylinder communication pipe butterfly valve and the front steam temperature measuring device 34 of the middle-low pressure cylinder communication pipe butterfly valve are respectively used for measuring the pressure and the temperature of the steam discharged by the middle pressure cylinder 2; a back steam pressure measuring device 37 is arranged behind the joint of the middle and low pressure cylinder communication pipe 35 and the heat supply steam main pipe 39 and on the middle and low pressure cylinder communication pipe 35; the middle-low pressure cylinder communication pipe butterfly valve rear steam pressure measuring device 37 is used for measuring the pressure of steam entering the low pressure cylinder 11 from the middle pressure cylinder 2; the front steam pressure measuring device 33 of the middle-low pressure cylinder communicating pipe butterfly valve, the front steam temperature measuring device 34 of the middle-low pressure cylinder communicating pipe butterfly valve and the rear steam pressure measuring device 37 of the middle-low pressure cylinder communicating pipe butterfly valve are respectively connected with the control device. The medium-low pressure cylinder communication pipe 35 is provided with a safety valve 28, and the safety valve 28 is connected with a control device. When the front steam pressure measuring device 33 of the middle and low pressure cylinder communication pipe butterfly valve measures that the pressure of the middle and low pressure cylinder communication pipe 35 at the outlet of the middle and low pressure cylinder 2 reaches the starting value of the safety valve 28, the control device controls the safety valve 28 to be opened, and when the front steam pressure measuring device 33 of the middle and low pressure cylinder communication pipe butterfly valve measures that the pressure of the middle and low pressure cylinder communication pipe 35 at the outlet of the middle and low pressure cylinder 2 reaches the safety value, the control device controls the safety valve 28 to be closed.
The high-pressure cylinder 1 is communicated with the condenser 17 through a high-pressure cylinder vacuumizing steam exhaust pipe 21; the high-pressure cylinder vacuumizing exhaust pipe 21 is provided with a high-pressure cylinder vacuumizing valve 22; the high-pressure cylinder vacuumizing valve 22 is connected with a control device. The high-pressure cylinder vacuumizing valve 22 is opened when the high-pressure cylinder exhaust check valve 23 is closed, and through-flow steam in the high-pressure cylinder 1 flows into the condenser 17 through the high-pressure cylinder vacuumizing valve 22 and the high-pressure cylinder vacuumizing exhaust pipe 21; when the cylinder exhaust check valve 23 is opened, it is closed.
The condenser 17 is respectively connected with a circulating water outlet pipe 14 and a circulating water inlet pipe 16; the circulating water inlet pipe 16 is provided with a circulating water inlet regulating valve 15; a condenser pressure measuring device 13 is arranged at the condenser 17 and is used for measuring the pressure of the condenser; the condenser 17 is connected with a vacuum pump exhaust pipe 20; the vacuum pump exhaust pipe 20 is provided with a vacuum pump exhaust check valve 19 and a vacuum pump 18; the circulating water inlet regulating valve 15 and the vacuum pump 18 are respectively connected with the controller. When no steam flows into the condenser 17 during long-term high back pressure operation of the unit, the control device closes the circulating water inlet regulating valve 15 to stop circulating water cooling, and closes the vacuum pump 18 to stop vacuumizing.
The low pressure cylinder 11 is provided with a low pressure cylinder exhaust steam temperature measuring device 12 for measuring the exhaust steam temperature of the low pressure cylinder; the low-pressure cylinder exhaust steam temperature measuring device 12 is connected with the control device.
The high-pressure cylinder 1 is connected to a boiler 24 via a high-pressure cylinder exhaust check valve 23. The boiler 24 and the low-pressure bypass valve of the steam turbine and the temperature reducing device 41 thereof are connected with the condenser 17. The boiler 24 is provided with a high-pressure regulating valve 26 on a pipe connected to the high-pressure cylinder 1. A medium pressure regulating valve 27 is provided on a pipe connecting the boiler 24 with the medium pressure cylinder 2. A turbine high-pressure bypass valve and a temperature reducing device 25 thereof are arranged between the pipeline connected with the medium-pressure cylinder 2 and the pipeline connected with the high-pressure cylinder 1 and the boiler 24 of the boiler 24.
In the embodiment, the low-pressure cylinder exhaust steam temperature measuring device 12 and the front steam temperature measuring device 34 of the middle-low pressure cylinder communication pipe butterfly valve adopt E-type thermocouples, the condenser pressure measuring device 13 and the front steam pressure measuring device 33 of the middle-low pressure cylinder communication pipe butterfly valve adopt EJA or Rosemount series pressure transmitters, and the conversion of temperature and pressure signals into electric signals is respectively realized. The vacuum pump exhaust check valve 19 and the high-pressure cylinder exhaust check valve 23 adopt pneumatic butterfly valves; the gearbox control module 31 includes a PLC controller; the butterfly valve 36 of the communication pipe of the medium-low pressure cylinder adopts a hydraulic regulating valve; the high-pressure regulating valve 26 and the medium-pressure regulating valve 27 are hydraulic regulating valves; the safety valve 28 is a pulse type safety valve; the low pressure cylinder rotation speed measuring device 32 can adopt an optoelectronic rotation speed sensor or an eddy current displacement sensor; the circulating water inlet regulating valve 15, the high-pressure cylinder vacuumizing valve 22 and the heating steam regulating valve 38 are pneumatic regulating valves or electric regulating valves.
According to the invention, the exhaust steam of the medium pressure cylinder 2 is led into the low pressure cylinder 11, the exhaust steam of the low pressure cylinder 11 flows into the condenser 17, the medium pressure cylinder communication pipe butterfly valve 36 can control the steam flow of the exhaust steam of the medium pressure cylinder 2 into the low pressure cylinder 11, when the low pressure cylinder is cut off, the medium pressure cylinder communication pipe butterfly valve 36 is fully closed, no steam enters the low pressure cylinder 11, and the unit is in high back pressure operation; when no steam flows into the condenser 17 during long-term high-back-pressure operation of the unit, the condenser 17 can close the circulating water inlet regulating valve 15 to stop circulating water cooling and close the vacuum pump 18 to stop vacuumizing; when the low pressure cylinder 11 is put into operation, the control device adjusts the opening of the middle and low pressure cylinder communicating pipe butterfly valve 36 to control the steam flow entering the low pressure cylinder 11, thereby controlling the output of the low pressure cylinder 11; the inner rotor of the low pressure cylinder 11 operates at half speed or less; the low-speed operation of half speed or less reduces the risk of the rotary blast over-temperature damage of the inner rotor of the low-pressure cylinder 11, as measured by the low-pressure cylinder rotational speed measuring means 32.
The butterfly valve 36 of the communication pipe of the middle and low pressure cylinders is closed to improve the flow of the unit for supplying steam to the outside through the heat supply steam header 40, and the heat supply steam adjusting valve 38 can be opened for supplying steam to the heat supply steam header 40 through the heat supply steam main pipe 39; the opening of the butterfly valve 36 of the communication pipe of the middle and low pressure cylinders can increase the steam flow of the exhaust steam of the middle pressure cylinder 2 to the low pressure cylinder 11.
S2: when the change-over switch module is disconnected, the generator 3 is disconnected with the low-pressure cylinder 11, the low-pressure cylinder 11 is cut off to operate, and the turbine generator set operates under a high back pressure working condition and supplies heat to the outside.
The turbine generator set operates under the working condition of high back pressure specifically as follows:
the rotor of the turbo generator set is in a low-speed jigger state, the low-pressure cylinder 11 is cut off and operated, and each valve is kept in a closed state;
the shaft seal of the steam turbine supplies steam, a vacuum pump 18 is started, a circulating water inlet regulating valve 15 is opened, and circulating water enters a condenser 17 through a circulating water inlet pipe 16 for cooling; when the display value of the condenser pressure measuring device 13 is not higher than P0, a high-pressure bypass valve of the steam turbine and a temperature reducing device 25 of the high-pressure bypass valve of the steam turbine are opened, the low-pressure bypass valve of the steam turbine and the temperature reducing device 41 of the low-pressure bypass valve of the steam turbine are matched with the boiler 24 to adjust the steam parameters of the outlet of the boiler, and the steam parameters of the outlet of the boiler are improved to meet the flushing requirement of the steam turbine;
the full-open high-pressure cylinder vacuumizing valve 22 is used for closing a low-pressure bypass valve of the turbine and a temperature reducing device 41 of the turbine, opening the high-pressure regulating valve 26 and the medium-pressure regulating valve 27 to flush the turbine, reaching the rated rotation speed of the generator, and opening the high-pressure regulating valve 26 to the minimum allowable opening CV 0 The rotation speed of the steam turbine is controlled by a medium-pressure regulating valve 27, and high-pressure cylinder 1 through-flow steam enters a condenser 17 through a high-pressure cylinder vacuumizing valve 22 and a high-pressure cylinder vacuumizing steam exhaust pipe 21; the steam pressure in the middle and low pressure cylinder communication pipe 35 exceeds the starting value of the safety valve by 1.2P Feed device The rear safety valve 28 is opened, the medium-pressure cylinder 2 discharges steam to the atmosphere through the safety valve 28, and at the moment, the heating steam regulating valve 38 can be opened to supply steam outwards through the heating steam main pipe 39 and the heating steam header 40; along with the increase of the steam supply, the steam pressure in the middle-low pressure cylinder communication pipe 35 is gradually reduced by Zhe and is lower than the closing value of the safety valve 28 by 0.95P Feed device The rear safety valve 28 is closed after the seat is returned, the steam supply is controlled by the opening degree of the medium pressure regulating valve 27, the generator power is determined by the flow steam quantity of the medium pressure cylinder 2, and the maximum generator power is not more than 30 percent P N ，P N Rated power for the turbine unit.
S3: when the change-over switch module is closed, the generator 3 is connected with the low-pressure cylinder 11, the low-pressure cylinder 11 is put into operation, and the steam turbine generator set operates under a condensing type working condition and supplies heat to the outside. The steam turbine generator set operates specifically under the condensing working condition:
the rotor of the turbo generator set is in a low-speed turning state, the low-pressure cylinder 11 is put into operation, and each valve is kept in a closed state;
starting a circulating water inlet regulating valve 15, supplying steam by a steam turbine shaft seal, starting a vacuum pump 18, starting the circulating water inlet regulating valve 15, and enabling circulating water to enter a condenser 17 through a circulating water inlet pipe 16 for cooling; the display value of the condenser pressure measuring device 13 is not higher than P 0 When the high-pressure bypass valve of the steam turbine and the temperature reducing device 25 thereof and the low-pressure bypass valve of the steam turbine and the temperature reducing device 41 thereof are started to cooperate with the boiler 24 to adjust steam parameters for operation, the steam parameters at the outlet of the boiler are improved to meet the flushing requirement of the steam turbine, and the butterfly valve 36 of the communication pipe of the full-open middle-low pressure cylinder is opened;
the full-open high-pressure cylinder vacuumizing valve 22 is used for closing a low-pressure bypass valve of the turbine and a temperature reducing device 41 of the turbine, opening the high-pressure regulating valve 26 and the medium-pressure regulating valve 27 to flush the turbine, achieving the rated rotation of the generator, and opening the high-pressure regulating valve 26 to the minimum allowable opening CV 0 The rotation speed of the steam turbine is controlled by a medium-pressure regulating valve 27, and high-pressure cylinder 1 through-flow steam enters a condenser 17 through a high-pressure cylinder vacuumizing valve 22 and a high-pressure cylinder vacuumizing steam exhaust pipe 21; the rotation speeds of the turbine and the generator rotor reach rated rotation speeds and are stabilized and then grid-connected for power generation; when the power of the generator reaches 30% P N When the high-pressure regulating valve 26 is opened, the high-pressure bypass valve of the steam turbine and the temperature reducing device 25 thereof are closed until the high-pressure bypass valve is completely closed; when the power of the generated electricity reaches 40 percent P N When the vacuum valve 22 of the high-pressure cylinder is closed, the steam exhaust check valve 23 of the high-pressure cylinder is opened; the opening degree of the high-pressure regulating valve 26 controls the power of the generator;
during the operation of the unit, the front steam pressure of the butterfly valve of the communication pipe of the middle and low pressure cylinders is controlled by adjusting the butterfly valve of the communication pipe of the middle and low pressure cylinders, and steam is supplied to the outside through the main pipe 39 and the header 40 of the heat supply steam by opening the regulating valve 38 of the heat supply steam.
The operation mode of the turbine generator set from pure condensing mode to high back pressure working condition switching is specifically as follows:
the turbine generator set is in pure condensing working condition operation, along with the increase of the opening of the heat supply steam regulating valve 38, the heat supply steam flow is increased outwards through the heat supply steam main pipe 39 and the heat supply steam header 40, the butterfly valve 36 of the communication pipe of the middle and low pressure cylinders is gradually turned off until the butterfly valve is fully turned off, the switch module is turned off, the low pressure cylinder 11 is cut off for operation, and the turbine generator set is switched from the pure condensing working condition to the high back pressure working condition operation mode. The condition that the turbine generator set is switched from the pure condensing type to the high back pressure working condition is as follows:
(1) The butterfly valve 36 of the communication pipe of the middle and low pressure cylinders is completely closed;
(2) The high-pressure regulating valve 26 is opened not smaller than the minimum allowable opening degree CV 0 。
The operation mode of switching the steam turbine generator set from high back pressure to pure condensing type or condensing type steam extraction and heat supply working conditions is specifically as follows:
the turbine generator set is operated under a high back pressure working condition; the low-pressure cylinder shaft seal supplies steam, a vacuum pump 18 is started, a circulating water inlet regulating valve 15 is opened, and circulating water enters a condenser 17 through a circulating water inlet pipe 16 for cooling; when the display value of the condenser pressure measuring device 13 is not higher than P0, a middle-low pressure cylinder communicating pipe butterfly valve 36 is opened, the speed of the low pressure cylinder rotor is gradually increased, when the rotating speed of the low pressure cylinder reaches a set value, a switch module is closed, the low pressure cylinder 11 is put into operation, and at the moment, the turbine generator set is switched from a high back pressure working condition to a pure condensing working condition operation mode;
After the steam turbine generator set is switched to operate under a pure condensing working condition, the opening of the butterfly valve 36 of the communication pipe of the middle and low pressure cylinders is increased to control the steam exhaust temperature of the low pressure cylinders to be less than 65 ℃; when no steam is supplied, the unit is in a pure condensing type working condition for operation; if the steam is required, the steam can be supplied to the outside through the main heat supply steam pipe 39 and the heat supply steam header 40 by opening the heat supply steam adjusting valve 38, and the unit is operated under the condensing steam extraction heat supply working condition.
The steam turbine generator set is switched from high back pressure to pure condensing type or condensing type steam extraction and heat supply working conditions:
(1) The display value of the condenser pressure measuring device 13 is not higher than P 0 ；
(2) The high-pressure regulating valve 26 is opened not smaller than the minimum allowable opening degree CV 0 。
In order to further explain the working principle of the invention, the following is a 300 MW unit as an example, and the main engines such as turbine wheels, boilers and the like can still adopt pure condensationThe final stage blade of the steam turbine can be used for no treatment. The steam turbine is subcritical, single intermediate reheating, two-cylinder two-exhaust steam and condensing steam turbine, and the model is: n300-16.7/538/538; the main design parameters of the steam turbine are shown in table 1. The subcritical n-type, control cycle, one-time intermediate reheating, single hearth, four corner tangential firing mode, swinging nozzle temperature regulation, balanced ventilation, solid slag discharging, all-steel suspension structure and open air arrangement coal-fired boiler with the boiler model SG-1025/17.5-M8, and the main design parameters are shown in Table 2. The gear ratio of the generator end transmission gear 8 to the generator end gear 4 is 1:1; the gear ratio of the low pressure cylinder end transmission gear 10 to the low pressure cylinder end gear 6 is 1:2. The temperature parameter of the heating steam is P Feed device =1.0 MPa, 300 ℃. The opening pressure of the safety valve 28 is 1.2MPa, the closing pressure of the back seat is 0.95MPa, the opening pressure and the closing pressure of the safety valve 28 are set according to the temperature parameter of the heating steam, and the opening pressure of the safety valve 28 is generally 1.2P Feed device The back seat closing pressure of the relief valve 28 is 0.95P Feed device 。
Table 1 main design parameters of steam turbine
Steam turbine model N300-16.7/538/538
Steam turbine type Subcritical, once intermediate reheat, two-cylinder two-exhaust and condensing steam turbine
Rated main valve front pressure 16.7MPa
Rated main valve front temperature 538℃
Rated reheat valve front temperature 538℃
Rated main steam flow 920.924t/h
Nameplate power (P) N ） 300MW
Operating rotational speed 3000r/min
Heat regeneration system 3 high plus +1 deaerator +4 low plus
Rated back pressure 6.4kPa
TABLE 2 design principal parameters of boiler
Project Numerical value
Maximum continuous evaporation capacity of boiler (B-MCR) 1025 t/h
Reheat steam flow 829 t/h
Superheater outlet vapor pressure（B-MCR） 17.5MPa.g
Superheated steam temperature 541℃
Reheat steam inlet/outlet steam pressure (B-MCR) 3.88/3.68
Reheat steam inlet/outlet steam temperature (B-MCR) 330/541℃
Reheat steam flow 815.2t/h
Water supply temperature 288℃
Working pressure of steam drum 18.87MPa.g
The unit operation mode and the regulation control steps are as follows:
in order to explain the unit operation mode and the regulation control process in detail, the conditions of a high back pressure working condition operation mode, a pure condensing mode to high back pressure working condition switching operation mode, a high back pressure to pure condensing working condition switching operation mode and the like are described.
1. High back pressure operating mode:
the rotor of the turbo generator set is in a low-speed jigger state, the control device sends a separation instruction to the gear box control module 31, the generator end transmission gear 8 is separated from the generator end gear 4, and the low-pressure cylinder end transmission gear 10 is separated from the low-pressure cylinder end gear 6. The other valves remain closed.
Starting a circulating water inlet regulating valve 15, supplying steam by a steam turbine shaft seal, starting a vacuum pump 18, starting the circulating water inlet regulating valve 15, and enabling circulating water to enter a condenser 17 through a circulating water inlet pipe 16 for cooling; the display value of the condenser pressure measuring device 13 is not higher than P 0 When the pressure is=20 kPa, the high-pressure bypass valve of the steam turbine and the temperature reducing device 25 thereof and the low-pressure bypass valve of the steam turbine and the temperature reducing device 41 thereof are opened to cooperate with the boiler 24 to adjust the steam parameters of the outlet of the boiler, so that the steam parameters of the outlet of the boiler are improved to meet the flushing requirement of the steam turbine.
The full-open high-pressure cylinder vacuumizing valve 22 is used for closing a low-pressure bypass valve of the steam turbine and a temperature reducing device 41 of the low-pressure cylinder vacuumizing valve, opening the high-pressure regulating valve 26 and the medium-pressure regulating valve 27 to flush the steam turbine, the target generator rotating speed is 3000r/min, and the high-pressure regulating valve 26 is opened to the minimum allowable opening CV 0 When the temperature is 8%, the temperature is kept unchanged, the rotation speed of the steam turbine is controlled by a medium-pressure regulating valve 27, and high-pressure cylinder 1 through-flow steam enters a condenser 17 through a high-pressure cylinder vacuumizing valve 22 and a high-pressure cylinder vacuumizing steam exhaust pipe 21; the front steam pressure measuring device 33 of the butterfly valve of the communication pipe of the middle and low pressure cylinders shows that the value exceeds the starting value of the safety valve by 1.2MPa, namely 1.2P Feed device The rear safety valve 28 is opened, the medium-pressure cylinder 2 discharges steam to the atmosphere through the safety valve 28, and at the moment, the heating steam regulating valve 38 can be opened to supply steam outwards through the heating steam main pipe 39 and the heating steam header 40; along with the increase of the steam supply, the display value of the front steam pressure measuring device 33 of the butterfly valve of the communication pipe of the middle and low pressure cylinders is gradually reduced by Zhe, which is lower than the closing value of the safety valve 28 by 0.95MPa, namely 0.95P Feed device The rear safety valve 28 is closed after the seat is returned, the steam supply is controlled by the opening degree of the medium pressure regulating valve 27, the generator power is determined by the flow steam quantity of the medium pressure cylinder 2, and the maximum generator power is not more than 30 percent P N I.e. 90MW, P N The power of the nameplate of the machine set.
When the power of the generator is required to reach 30% P N . I.e. 90MW, when the medium pressure regulating valve 27 is fully opened, the opening degree of the high pressure regulating valve 26 is gradually increased, and the high pressure bypass valve of the steam turbine and the temperature reducing device 25 are closed until the temperature reducing device is fully closed; when the power of the generated electricity reaches 40 percent P N I.e. 120MW, the high pressure cylinder vacuum valve 22 is closed and the high pressure cylinder exhaust check valve 23 is opened. The low pressure cylinder 11 can stop shaft sealing and supply according to the requirement when the high back pressure operatesWhen no steam flows into the condenser 17 during long-term high-back pressure operation, the condenser 17 can close the circulating water inlet regulating valve 15 to stop circulating water cooling, and close the vacuum pump 18 to stop vacuumizing.
The operations of power reduction of the generator, unit shutdown and the like can be completed by referring to the power increase of the generator and the starting working condition of the unit.
2. The operation mode of pure condensing type working conditions is as follows:
the rotor of the turbo generator set is in a low-speed jigger state, and an aerial gearbox control module 31 of the control device performs 'meshing' operation to realize that a generator end transmission gear 8 is meshed with a generator end gear 4, and a low-pressure cylinder end transmission gear 10 is meshed with a low-pressure cylinder end gear 6. The other valves remain closed.
Starting a circulating water inlet regulating valve 15, supplying steam by a steam turbine shaft seal, starting a vacuum pump 18, starting the circulating water inlet regulating valve 15, and enabling circulating water to enter a condenser 17 through a circulating water inlet pipe 16 for cooling; the display value of the condenser pressure measuring device 13 is not higher than P 0 When the absolute pressure value is equal to 20kPa, the high-pressure bypass valve of the steam turbine and the temperature reducing device 25 thereof and the low-pressure bypass valve of the steam turbine and the temperature reducing device 41 thereof are opened to cooperate with the boiler 24 to adjust the steam parameters for operation, so that the steam parameters at the outlet of the boiler are improved to meet the flushing requirement of the steam turbine, and the butterfly valve 36 of the communication pipe of the middle-low pressure cylinder is fully opened.
The full-open high-pressure cylinder vacuumizing valve 22 is used for closing a low-pressure bypass valve of the turbine and a temperature reducing device 41 of the turbine, the high-pressure regulating valve 26 and the medium-pressure regulating valve 27 are opened to flush the turbine, the rated rotating speed of the target generator is 3000r/min, and the high-pressure regulating valve 26 is opened to the minimum allowable opening CV 0 When the temperature is 8%, the temperature is kept unchanged, the rotation speed of the steam turbine is controlled by a medium-pressure regulating valve 27, and high-pressure cylinder 1 through-flow steam enters a condenser 17 through a high-pressure cylinder vacuumizing valve 22 and a high-pressure cylinder vacuumizing steam exhaust pipe 21; the rotation speed of the rotor of the steam turbine and the generator reaches 3000r/min and is stabilized, and then grid-connected power generation is performed, wherein the rotation speed of the rotor of the low-pressure cylinder 11 is 1500r/min; when the power of the generator reaches 30% P N I.e. 90MW, increasing the opening of the high-pressure regulating valve 26 one by one, and closing the high-pressure bypass valve of the steam turbine and the temperature reducing device 25 until the high-pressure bypass valve is completely closed; when the power of the generated electricity reaches 40 percent P N I.e. 120MW, the high-pressure cylinder is closed to vacuumizeA valve 22, a high-pressure cylinder exhaust check valve 23 is opened; the opening of the high pressure regulator valve 26 controls the generator power.
During the operation of the unit, the front steam pressure of the butterfly valve of the communication pipe of the middle and low pressure cylinders can be controlled by adjusting the butterfly valve of the communication pipe of the middle and low pressure cylinders, and steam is supplied to the outside through the main pipe 39 and the header 40 of the heat supply steam by opening the regulating valve 38 of the heat supply steam.
The operations of power reduction of the generator, unit shutdown and the like can be completed by referring to the power increase of the generator and the starting working condition of the unit.
3. The operation mode is switched from pure condensing mode to high back pressure working condition:
the unit is in pure condensing type working condition operation, along with increasing the opening of the heating steam regulating valve 38 and increasing the flow of heating steam outwards through the heating steam main pipe 39 and the heating steam header 40, the middle-low pressure cylinder communicating pipe butterfly valve 36 is gradually turned off until the unit is completely turned off, the control device controls the gear box control module 31 to send a separation instruction, the generator end transmission gear 8 is separated from the generator end gear 4, and the low pressure cylinder end transmission gear 10 is separated from the low pressure cylinder end gear 6. At this time, the unit is switched from a pure condensing type working condition to a high back pressure working condition operation mode.
Pure condensing type to high back pressure working condition switching operation mode switching conditions:
(1) The butterfly valve 36 of the communication pipe of the middle and low pressure cylinders is fully closed, namely 0 percent;
(2) The high-pressure regulating valve 26 is opened not smaller than the minimum allowable opening degree CV0, CV 0 =8%。
4. The high back pressure is towards pure condensing or condensing type steam extraction heat supply operating mode switching operation mode:
the unit is operated under a high back pressure working condition; the low-pressure cylinder shaft seal supplies steam, a vacuum pump 18 is started, a circulating water inlet regulating valve 15 is opened, and circulating water enters a condenser 17 through a circulating water inlet pipe 16 for cooling; the display value of the condenser pressure measuring device 13 is not higher than P 0 When the value of the low-pressure cylinder rotating speed measuring device 32 is stabilized at half rated rotating speed, namely 1500r/min, the gear box control module 31 sends out an engagement instruction to realize the transmission gear 8 at the generator end and the sending of the gearThe motor end gear 4 is meshed, and the low-pressure cylinder end transmission gear 10 is meshed with the low-pressure cylinder end gear 6. At this time, the unit is switched from a high back pressure working condition to a pure condensing working condition operation mode. After the operation is switched to the pure condensing type working condition, the display value of the low-pressure cylinder exhaust steam temperature measuring device 12 is observed, and the opening degree of the butterfly valve 36 of the communication pipe of the middle and low pressure cylinders is further increased so as to control the display value of the low-pressure cylinder exhaust steam temperature measuring device 12 to be smaller than 65 ℃. When no steam is supplied, the unit is in a pure condensing type working condition for operation; if the steam is required, the steam can be supplied to the outside through the main heat supply steam pipe 39 and the heat supply steam header 40 by opening the heat supply steam adjusting valve 38, and the unit is operated under the condensing steam extraction heat supply working condition.
High back pressure is to pure condensing or condensing formula extraction of steam heat supply operating mode switching condition:
(1) The display value of the condenser pressure measuring device 13 is not higher than P 0 =20kPa；
(2) The high-pressure regulating valve 26 is opened not smaller than the minimum allowable opening degree CV 0 =8%。
Those of ordinary skill in the art will appreciate that the elements of the examples described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both, and that the elements of the examples have been described generally in terms of functionality in the foregoing description to clearly illustrate this interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
In the embodiments provided in this application, it should be understood that the division of units is merely a logic function division, and there may be other manners of division in practical implementation, for example, multiple units may be combined into one unit, one unit may be split into multiple units, or some features may be omitted.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the invention, and are intended to be included within the scope of the appended claims and description.

Claims (7)

1. A heat supply method for switching condensing type and high back pressure of a turbine generator set comprises a boiler (24), a high-pressure cylinder (1), a medium-pressure cylinder (2), a generator (3) and a low-pressure cylinder (11); the method is characterized in that: the method comprises the following steps:
s1: the boiler (24) is respectively connected with the high-pressure cylinder (1) and the medium-pressure cylinder (2); connecting the medium-pressure cylinder (2) with a generator (3); the generator (3) is connected with the low-pressure cylinder (11) through a change-over switch module; the middle pressure cylinder (2) is connected with the low pressure cylinder (11) through a middle and low pressure cylinder communication pipe (35); the middle-low pressure cylinder communication pipe (35) is connected with a heat supply steam header (40) through a heat supply steam main pipe (39) to realize external heat supply;
S2: when the change-over switch module is disconnected, the generator (3) is disconnected with the low-pressure cylinder (11), the low-pressure cylinder (11) is cut off to operate, and the turbine generator set operates under a high back pressure working condition and supplies heat to the outside;
s3: when the change-over switch module is closed, the generator (3) is connected with the low-pressure cylinder (11), the low-pressure cylinder (11) is put into operation, and the steam turbine generator set operates under a condensing type working condition and supplies heat to the outside;
the change-over switch module realizes the change-over of the operation condition of the steam turbine generator set in a gear meshing and separating mode;
the change-over switch module comprises a gear box control module (31), a gear driving motor (29) and a gear box (5); a generator end gear (4), a low-pressure cylinder end gear (6), a generator end transmission gear (8) and a low-pressure cylinder end transmission gear (10) are arranged in the gear box (5); the generator end gear (4) is connected with the generator (3); the low-pressure cylinder end gear (6) is connected with the low-pressure cylinder (11); the generator end transmission gear (8) is rigidly connected with the low-pressure cylinder end transmission gear (10) through a transmission shaft (9); the generator end transmission gear (8) is sleeved on the bearing (7); the gear box control module (31) is connected with the gear driving motor (29); an output shaft of the gear driving motor (29) is connected with the bearing (7); the generator (3) and the low-pressure cylinder (11) are arranged on the same axis center line;
The gear box control module (31) sends out a separated control signal, the gear driving motor (29) drives the generator end transmission gear (8) to translate leftwards or rightwards, the generator end transmission gear (8) is separated from the generator end gear (4), the low-pressure cylinder end transmission gear (10) is separated from the low-pressure cylinder end gear (6), and then the low-pressure cylinder (11) is cut off;
the gear ratio of the generator end transmission gear (8) to the generator end gear (4) is 1:1; the gear ratio of the low-pressure cylinder end transmission gear (10) to the low-pressure cylinder end gear (6) is less than or equal to 1:2.
2. The heat supply method for switching between condensing type and high back pressure of a turbine generator set according to claim 1, wherein the heat supply method comprises the following steps: in the step S2, the operation of the turbine generator set under the working condition of high back pressure specifically includes:
the rotor of the turbo generator set is in a low-speed jigger state, the low-pressure cylinder (11) is cut off and operated, and each valve is kept in a closed state;
the shaft seal of the steam turbine supplies steam, a vacuum pump (18) is started, a circulating water inlet regulating valve (15) is opened, and circulating water enters a condenser (17) through a circulating water inlet pipe (16) for cooling; when the display value of the condenser pressure measuring device (13) is not higher than P 0 When the high-pressure bypass valve of the steam turbine and the temperature reducing device (25) thereof are opened, the low-pressure bypass valve of the steam turbine and the temperature reducing device (41) thereof are matched with the boiler (24) to adjust the steam parameters of the outlet of the boiler, and the steam parameters of the outlet of the boiler are improved to meet the flushing requirement of the steam turbine;
a full-open high-pressure cylinder vacuumizing valve (22), a low-pressure bypass valve of the turbine and a temperature reducing device (41) thereof are closed, a high-pressure regulating valve (26) and a medium-pressure regulating valve (27) are opened to flush the turbine, the rated rotation speed of the generator is reached, and the high-pressure regulating valve (26) is opened to the minimum allowable opening CV 0 The rotation speed of the steam turbine is controlled by a medium-pressure regulating valve (27), and high-pressure cylinder (1) through-flow steam enters a condenser (17) through a high-pressure cylinder vacuumizing valve (22) and a high-pressure cylinder vacuumizing steam exhaust pipe (21); the steam pressure in the middle-low pressure cylinder communicating pipe (35) exceeds the starting value of the safety valve by 1.2P Feed device The rear safety valve (28) is opened, the exhaust steam of the medium pressure cylinder (2) is discharged to the atmosphere through the safety valve (28), and at the moment, the heat supply steam regulating valve (38) is opened to supply steam outwards through the heat supply steam main pipe (39) and the heat supply steam header (40); along with the increase of the steam supply, the steam pressure in the middle-low pressure cylinder communicating pipe (35) is gradually reduced by Zhe and is lower than the closing value of the safety valve (28) by 0.95P Feed device The rear safety valve (28) is closed after the seat is returned, the steam supply is controlled by the opening degree of the medium pressure regulating valve (27), the power of the generator is determined by the flow steam quantity of the medium pressure cylinder (2), and the maximum value of the power of the generator is not more than 30 percent P N ，P N Rated power for the turbine unit.
3. The heat supply method for switching between condensing type and high back pressure of a turbine generator set according to claim 1, wherein the heat supply method comprises the following steps: in the step S3, the operation of the steam turbine generator set under the condensing working condition specifically includes:
the rotor of the turbo generator set is in a low-speed turning state, the low-pressure cylinder (11) is put into operation, and each valve is kept in a closed state;
starting a circulating water inlet regulating valve (15), supplying steam by a steam turbine shaft seal, starting a vacuum pump (18), starting the circulating water inlet regulating valve (15), and enabling circulating water to enter a condenser (17) through a circulating water inlet pipe (16) for cooling; the display value of the condenser pressure measuring device (13) is not higher than P 0 When in use, the high-pressure bypass valve of the steam turbine and the temperature reducing device (25) thereof are opened, and the low-pressure bypass valve of the steam turbine and the temperature reducing device (41) thereof are matchedThe boiler (24) is closed to adjust steam parameters for operation, the steam parameters at the outlet of the boiler are lifted to meet the flushing requirement of the steam turbine, and a butterfly valve (36) of a communication pipe of the middle-low pressure cylinder is fully opened;
A full-open high-pressure cylinder vacuumizing valve (22), a low-pressure bypass valve of the turbine and a temperature reducing device (41) thereof are closed, a high-pressure regulating valve (26) and a medium-pressure regulating valve (27) are opened to flush the turbine, the rated rotation of the generator is achieved, and the high-pressure regulating valve (26) is opened to the minimum allowable opening CV 0 The speed of the steam turbine is controlled by a medium-pressure regulating valve (27), and high-pressure cylinder (1) through-flow steam enters a condenser (17) through a high-pressure cylinder vacuumizing valve (22) and a high-pressure cylinder vacuumizing steam exhaust pipe (21); the rotation speeds of the turbine and the generator rotor reach rated rotation speeds and are stabilized and then grid-connected for power generation; when the power of the generator reaches 30% P N When the steam turbine is in operation, the opening of the high-pressure regulating valve (26) is gradually increased, and the high-pressure bypass valve of the steam turbine and the temperature reducing device (25) thereof are closed until the steam turbine is completely closed; when the power of the generated electricity reaches 40 percent P N When the vacuum valve (22) of the high-pressure cylinder is closed, the steam exhaust check valve (23) of the high-pressure cylinder is opened; the opening degree of the high-pressure regulating valve (26) controls the power of the generator;
in the running process of the unit, the front steam pressure of the butterfly valve of the communication pipe of the middle and low pressure cylinder is controlled by adjusting the butterfly valve (36) of the communication pipe of the middle and low pressure cylinder, and steam is supplied outwards through a main pipe (39) of the heat supply steam and a header (40) of the heat supply steam by opening a regulating valve (38) of the heat supply steam.
4. A method for providing heat for switching between condensing mode and high back pressure of a steam turbine generator set according to claim 3, wherein: the operation mode of the turbine generator set from pure condensing mode to high back pressure working condition switching is specifically as follows:
the turbine generator set is in pure condensing working condition operation, along with increasing the opening of a heat supply steam regulating valve (38), the heat supply steam flow is increased outwards through a heat supply steam main pipe (39) and a heat supply steam header (40), a middle-low pressure cylinder communicating pipe butterfly valve (36) is turned off from Zhejiang to full-closed, a switch module is disconnected, a low pressure cylinder (11) is cut off for operation, and the turbine generator set is switched into a high back pressure working condition operation mode from the pure condensing working condition.
5. The heat supply method for switching between condensing type and high back pressure of a turbine generator set according to claim 2, wherein the heat supply method comprises the following steps: the operation mode of switching the steam turbine generator set from high back pressure to pure condensing type or condensing type steam extraction and heat supply working conditions is specifically as follows:
the turbine generator set is operated under a high back pressure working condition; the low-pressure cylinder shaft seal supplies steam, a vacuum pump (18) is started, a circulating water inlet regulating valve (15) is opened, and circulating water enters a condenser (17) through a circulating water inlet pipe (16) for cooling; the display value of the condenser pressure measuring device (13) is not higher than P 0 When the rotating speed of the low-pressure cylinder reaches a set value, a change-over switch module is closed, the low-pressure cylinder (11) is put into operation, and at the moment, the turbine generator set is switched from a high back pressure working condition to a pure condensing working condition operation mode;
after the steam turbine generator set is switched to operate under a pure condensing working condition, the opening degree of a butterfly valve (36) of a communication pipe of the middle and low pressure cylinders is increased to control the steam exhaust temperature of the low pressure cylinders to be less than 65 ℃; when no steam is supplied, the unit is in a pure condensing type working condition for operation; if the steam is required to be supplied, the heat supply steam regulating valve (38) is opened, the steam is supplied to the outside through the heat supply steam main pipe (39) and the heat supply steam header (40), and the unit is in the condensing type steam extraction heat supply working condition to operate.
6. The heat supply method for switching between condensing type and high back pressure of a turbine generator set according to claim 4, wherein the heat supply method comprises the following steps: the condition that the turbine generator set is switched from the pure condensing type to the high back pressure working condition is as follows:
(1) The butterfly valve (36) of the communication pipe of the middle and low pressure cylinders is fully closed;
(2) The high-pressure regulating valve (26) is opened to be not smaller than the minimum allowable opening CV 0 。
7. The heat supply method for switching between condensing type and high back pressure of a turbine generator set according to claim 5, wherein the heat supply method comprises the following steps: the steam turbine generator set is switched from high back pressure to pure condensing type or condensing type steam extraction and heat supply working conditions:
(1) The display value of the condenser pressure measuring device (13) is not higher than P 0 ；
(2) The high-pressure regulating valve (26) is opened to be not smaller than the minimum allowable opening CV 0 。
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Publication number Priority date Publication date Assignee Title
GB396291A (en) * 1932-06-21 1933-08-03 Bauer Gustav Marine engine plant
GB486395A (en) * 1937-05-03 1938-06-02 Bauer Gustav Improvements in multi stage steam engine plants
CN206571537U (en) * 2017-01-23 2017-10-20 喀什德力克石油工程技术有限公司 A kind of steam turbine electric barring equipment and turbine generating system
CN111927569A (en) * 2020-08-31 2020-11-13 西安热工研究院有限公司 Steam turbine system and method for improving flexibility of heat supply unit

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB396291A (en) * 1932-06-21 1933-08-03 Bauer Gustav Marine engine plant
GB486395A (en) * 1937-05-03 1938-06-02 Bauer Gustav Improvements in multi stage steam engine plants
CN206571537U (en) * 2017-01-23 2017-10-20 喀什德力克石油工程技术有限公司 A kind of steam turbine electric barring equipment and turbine generating system
CN111927569A (en) * 2020-08-31 2020-11-13 西安热工研究院有限公司 Steam turbine system and method for improving flexibility of heat supply unit

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