CN115095393A - Hydraulic turbine power generation system for redundant flow energy recovery - Google Patents
Hydraulic turbine power generation system for redundant flow energy recovery Download PDFInfo
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- CN115095393A CN115095393A CN202210527368.8A CN202210527368A CN115095393A CN 115095393 A CN115095393 A CN 115095393A CN 202210527368 A CN202210527368 A CN 202210527368A CN 115095393 A CN115095393 A CN 115095393A
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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
- F01D15/00—Adaptations of machines or engines for special use; Combinations of engines with devices driven thereby
- F01D15/10—Adaptations for driving, or combinations with, electric generators
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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
- F01D17/00—Regulating or controlling by varying flow
- F01D17/10—Final actuators
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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
- F01D21/00—Shutting-down of machines or engines, e.g. in emergency; Regulating, controlling, or safety means not otherwise provided for
- F01D21/003—Arrangements for testing or measuring
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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
- F22—STEAM GENERATION
- F22D—PREHEATING, OR ACCUMULATING PREHEATED, FEED-WATER FOR STEAM GENERATION; FEED-WATER SUPPLY FOR STEAM GENERATION; CONTROLLING WATER LEVEL FOR STEAM GENERATION; AUXILIARY DEVICES FOR PROMOTING WATER CIRCULATION WITHIN STEAM BOILERS
- F22D5/00—Controlling water feed or water level; Automatic water feeding or water-level regulators
- F22D5/26—Automatic feed-control systems
- F22D5/32—Automatic feed-control systems influencing the speed or delivery pressure of the feed pumps
Abstract
The present application relates to a hydraulic turbine power generation system for redundant flow energy recovery, comprising: a boiler feed water pump including an inlet and an outlet through which a liquid working medium is supplied to the power plant boiler at a predetermined head and flow rate; the turbine comprises an inlet, an outlet, an impeller and a rotating shaft, wherein the inlet of the turbine is connected with the outlet of the boiler feed water pump in a fluid communication way; the rotating shaft of the generator is connected with the rotating shaft of the turbine through a coupler; and the deaerator comprises a plurality of working medium inlets, a working medium outlet and at least one exhaust port, at least one of the working medium inlets is communicated and connected with the outlet of the turbine in a fluid mode, and the working medium outlet of the deaerator is communicated and connected with the inlet of the boiler feed water pump in a fluid mode. The turbine receives a preset redundant flow of working medium from a boiler feed water pump, absorbs the pressure energy of the working medium, and drives a rotating shaft of the turbine to rotate so as to generate electricity. The turbine generates electricity using only a predetermined redundant flow of boiler feed water pump.
Description
Technical Field
The present application relates to energy recovery in a production line of a power plant, and more particularly, to a hydraulic turbine power generation system for energy recovery of a redundant flow of working medium downstream of a boiler feed pump in a power plant.
Background
The main machine of the thermal power plant or thermal power plant comprises a boiler, a steam turbine and a generator, coal, oil or gas is used as a power source, the circulation of a working medium which is mainly water is used as a driving force, and the steam turbine generator unit generates electricity and contributes about 60% of electric power to a national power grid. Thermal power plants can use waste heat to provide steam to industrial users, such as petrochemical plants, and also to provide heating for residents.
The supply of the working medium to the boiler or the circulation of the working medium outside the unit is effected by a boiler feed water pump. The boiler feed water pump has inherent lift-flow characteristic (curve), and is matched with the pressure-flow required by the boiler operation when the boiler feed water pump is designed and selected, namely the lift-flow of the boiler feed water pump is slightly larger than the pressure-flow required by the boiler operation. However, in actual operation, the power supply amount of the steam turbine generator unit of the power plant is controlled by the power grid schedule, and the required working medium amount of the boiler is reduced along with the reduction of the power supply amount. The difference between the flow provided by the boiler feed water pump and the flow required by the boiler may be referred to as a redundant flow. In order to ensure the operation safety of the boiler feed pump, the redundant flow is released by configuring a recirculation system of the boiler feed pump in the prior art, namely, part of high-temperature and high-pressure water at the outlet of the boiler feed pump is decompressed by the recirculation valve and then returns to the deaerator, so that the actual operation flow of the boiler feed pump at any time is not lower than the minimum flow working condition requirement, and the safe and stable operation of the boiler feed pump during starting, stopping and quick adjustment is ensured by consuming part of energy.
According to the national strategy for realizing the targets of carbon peak reaching and carbon neutralization, the nation preferentially develops non-fossil energy sources, such as photovoltaic power generation, wind power generation, hydropower and nuclear power, so that the traditional thermal power generating unit gradually develops towards the directions of high capacity, high parameter and participation in deep peak regulation, more and more units are flexibly transformed, the opening frequency of a recirculation valve is higher and longer, particularly, the units are in a low-load working condition during the low-ebb electricity consumption period at night, a recirculation valve needs to be opened for a long time to operate, and therefore more and more energy is consumed.
Therefore, the problem of how to recover the redundant flow of the boiler water supply system needs to be solved.
Disclosure of Invention
The technical problem that this application will be solved is to recycle the redundant flow of boiler feed water pump export when the generating set low-load operation of thermal power plant or thermal power plant realizes energy saving and emission reduction.
To solve the above technical problem, according to an aspect of the present application, there is provided a hydraulic turbine power generation system for redundant flow energy recovery, including: a boiler feed pump comprising an inlet and an outlet through which a liquid working medium is provided to the power plant boiler at a predetermined head and flow rate; the turbine comprises an inlet, an outlet, an impeller and a rotating shaft, wherein the inlet of the turbine is connected with the outlet of the boiler feed water pump in a fluid communication way; the rotating shaft of the generator is connected with the rotating shaft of the turbine through a coupler; and the deaerator comprises a plurality of working medium inlets, a working medium outlet and at least one exhaust port, at least one of the working medium inlets is communicated and connected with the outlet of the turbine in a fluid mode, and the working medium outlet of the deaerator is communicated and connected with the inlet of the boiler feed water pump in a fluid mode. The turbine receives a preset redundant flow of working medium from a boiler feed water pump, absorbs the pressure energy of the working medium, and drives a rotating shaft of the turbine to rotate so as to generate power. The turbine generates electricity using only a predetermined redundant flow of boiler feed water pump.
According to an embodiment of the present application, the hydraulic turbine power generation system for redundant flow energy recovery may further include a main high pressure pipeline leading from an outlet of the boiler feed water pump to the boiler, and a check valve, a gate valve, and a flow measuring device sequentially disposed on the main high pressure pipeline.
According to embodiments of the present application, the hydraulic turbine power generation system for redundant flow energy recovery may further include a boiler economizer, and the main conduit may lead to the boiler through the boiler economizer.
According to the embodiment of the application, the fluid communication connection between the working medium outlet of the deaerator and the inlet of the boiler feed water pump can comprise a first pipeline, and a pressure sensor, a gate valve and a flow measuring device which are sequentially arranged on the first pipeline.
According to an embodiment of the present application, the connection of the inlet of the turbine in fluid communication with the outlet of the boiler feed water pump may comprise a third line and a pressure regulating valve and a gate valve disposed on the third line.
According to an embodiment of the application, the at least one of the plurality of working medium inlets being connected in fluid communication with the outlet of the turbine may comprise a fifth line and an isolation valve and a non-return valve arranged on the fifth line.
According to an embodiment of the present application, the hydraulic turbine power generation system for redundant flow energy recovery may further include a second pipeline fluidly connecting an outlet of the boiler feed water pump and one of the plurality of working medium inlets of the deaerator, and a pre-recirculation isolation valve, a recirculation valve, a post-recirculation isolation valve, and a check valve disposed on the second pipeline.
According to embodiments of the application, the boiler feed water pump may be a multi-stage centrifugal impeller series combination feed water pump.
According to embodiments of the application, the power generated by the generator may be incorporated into the utility grid through a transformer.
According to an embodiment of the application, a power plant boiler may provide steam power for a peaking turbine generator set.
According to embodiments of the present application, the working medium may be treated water and necessary agents dissolved in the water.
According to an embodiment of the application, a hydraulic turbine power generation system for redundant flow energy recovery has a first operating mode, a second operating mode, and a third operating mode under different operating conditions, the first to third operating modes being switched by valve opening/closing in the system.
According to an embodiment of the application, in a first mode of operation, the boiler feed water pump delivers working medium only to the power plant boiler; in the second operation mode, the pressure regulating valve on the third pipeline is closed, the recirculation valve on the second pipeline is opened, the boiler feed water pump can convey working media to the boiler of the power plant, and meanwhile, the safe and stable operation of the boiler feed water pump can be maintained through the flow dividing part of the recirculation valve on the second pipeline; in the third operation mode, the pressure regulating valve on the third pipeline is opened, the recirculation valve on the second pipeline is closed, the boiler feed water pump can deliver the working medium to the boiler of the power plant, and meanwhile, the redundant flow of the working medium can be provided for the turbine through the third pipeline and drives the generator to generate power so as to recover the pressure energy of the working medium.
According to another aspect of the present application, there is provided a control system of a hydraulic turbine power generation system for redundant flow energy recovery, the hydraulic turbine power generation system for redundant flow energy recovery including a deaerator for collecting and deaerating each path of a working medium, a boiler feed pump for supplying the working medium to a boiler of a power plant, a hydraulic turbine power generation unit for redundant flow using the boiler feed pump, a recirculation valve for overpressure protection, and a first pipeline connecting an outlet of the deaerator to an inlet of the boiler feed pump, a second pipeline connecting an outlet of the boiler feed pump to an inlet of the deaerator via the recirculation valve, a third pipeline connecting an outlet of the boiler feed pump to an inlet of the hydraulic turbine power generation unit via the hydraulic turbine power generation unit, a fourth pipeline connecting an outlet of the boiler feed pump to the boiler of the power plant, a fifth pipeline connecting an outlet of the hydraulic turbine power generation unit to an inlet of the deaerator, a control system, comprising: the distributed computer controller DCS sends a control signal to the user side based on the input signal and a preset algorithm and is communicated with a main control room of the power plant; and the pressure transmitter outputs a pressure signal of an outlet of the boiler feed water pump to the distributed computer controller DCS. The distributed computer controller DCS receives a pressure signal of an outlet of the boiler feed water pump output by the pressure transmitter, divides the received pressure signal of the outlet of the boiler feed water pump into three operation modes, namely a first operation mode, a second operation mode and a third operation mode, and switches the first operation mode to the third operation mode through valve opening/closing in the system. The distributed computer controller DCS conducts the third pipeline only in the third operation mode and operates the hydraulic turbine generator set to generate power.
According to an embodiment of the present application, the control system of the hydraulic turbine power generation system for redundant flow energy recovery may further include a first pressure transmitter disposed at an outlet of the deaerator, a second pressure transmitter disposed at an inlet of the boiler feed water pump, a third pressure transmitter disposed at an outlet of the boiler feed water pump, a fourth pressure transmitter disposed at an inlet of the hydraulic turbine, a fifth pressure transmitter disposed at an outlet of the hydraulic turbine, and a sixth pressure transmitter disposed at an inlet of the power plant boiler. And the distributed computer controller DCS receives the pressure signal from the pressure transmitter, and comprehensively judges the operation condition of the hydraulic turbine power generation system for recovering the redundant flow energy according to a preset algorithm by combining the pressure signal from the pressure transmitter, so as to determine the next operation step.
According to an embodiment of the application, the first operation mode may be an operation mode in which the load of the power plant turbo unit is above 70% of the design load, the second operation mode may be an operation mode in which the load of the power plant turbo unit is 60% to 70% of the design load, the third operation mode may be an operation mode in which the load of the power plant turbo unit fluctuates around 40% to 50% of the design load, and the third operation mode may further include an operation mode in which deep peaking to a lower level may occur according to scheduling of the power grid.
According to an embodiment of the present application, the control system of the hydraulic turbine power generation system for redundant flow energy recovery may further include a pressure regulating valve and a gate valve provided on the third line, the gate valve V7 and the recirculation valve V3 being closed in the first operation mode; in the second operating mode, recirculation valve V3 is open and gate valve V7 is closed; in the third operation mode, the pressure regulating valve V6 and the gate valve V7 are opened, and the recirculation valve V3 is closed.
According to an embodiment of the present application, the control system of the hydraulic turbine power generation system for redundant flow energy recovery may further include a flow measurement device SG1 provided at an inlet of the boiler feed water pump and a flow measurement device SG2 provided at an inlet of the power plant boiler E3.
According to an embodiment of the present application, the control system of the hydraulic turbine power generation system for redundant flow energy recovery may further include differential pressure transmitters DPT1 and DPT2 respectively disposed at both ends of the flow measuring devices SG1 and SG2, and differential pressure signals generated by the differential pressure transmitters DPT1 and DPT2 are transmitted to the distributed computer controller DCS and flow distribution calculations are made.
According to an embodiment of the present application, in the third mode of operation, the redundant flow of the third line is equal to the difference between the flows measured by flow measuring devices SG1 and SG 2.
According to an embodiment of the present application, the control system of the hydraulic turbine power generation system for redundant flow energy recovery may further include a rotational speed measurement probe SE1, SE2, SE3 for monitoring the rotational speed of the hydraulic turbine, the distributed computer controller DCS controls the pressure regulating valve V6 and the gate valve V7 to increase the opening degree when the rotational speed of the hydraulic turbine E4 is lower than the rated rotational speed of the generator E5, controls the pressure regulating valve V6 and the gate valve V7 to decrease the opening degree when the rotational speed of the hydraulic turbine E4 is higher than the rated rotational speed of the generator E5, and closes the pressure regulating valve V6 and the gate valve V58 3 9 and opens the recirculation valve V2 when the rotational speed of the hydraulic turbine E4 is higher than the rated rotational speed of the generator E5 and controls the pressure regulating valve V6 and the gate valve V7 to decrease the opening degree inefficiently.
According to an embodiment of the application, the distributed computer controller DCS may be a subsystem of a main control room of the power plant, in any case, the distributed computer controller DCS operates under the main control room of the power plant.
Compared with the prior art, the embodiment of the application can at least realize the following beneficial effects:
the hydraulic turbine power generation system for redundant flow energy recovery according to the embodiment of the application comprises a set of turbine power generation unit connected between an outlet of a boiler feed water pump and an inlet of a deaerator, wherein the turbine receives working medium with preset redundant flow from the boiler feed water pump, absorbs pressure energy of the working medium to drive a rotating shaft of the turbine and drive the rotating shaft of the power generator to rotate so as to generate power, and the turbine only generates power by using the preset redundant flow of the boiler feed water pump. The recoverable redundant flow energy of the hydraulic turbine power generation system for recovering the redundant flow energy is huge, and by taking a 1000MW power generation unit as an example, the maximum recoverable energy per hour is 2300kW, and the annual energy generation amount is about 690 ten thousand kWH, so that the hydraulic turbine power generation system has a good energy-saving effect. If the energy is not recovered, the redundant flow flows back to the deaerator after being decompressed by the recirculation valve, the burden is increased on the recirculation valve, the abrasion is accelerated, the working medium is vaporized by the recirculation valve in the decompression process, the working burden of the deaerator is increased, and the heat emission generated in the decompression process is pollution to the ambient air. In addition, because the turbine absorbs redundant flow, the deterioration of the operation condition of the boiler feed pump can be reduced when the turbo generator set operates at low load, namely the flow of the boiler feed pump is properly increased under the condition that the outlet pressure is kept in a reasonable range, so that the boiler feed pump can be kept to operate at a better condition, and the energy consumed by the boiler feed pump can be completely recovered and compensated in the hydraulic turbo generator set. The electric power generated by the hydraulic turbine generator set can be directly merged into the auxiliary power grid of the power plant after being transformed by the transformer, so that the electric power consumption of the power plant to the national power grid is reduced, and meanwhile, the electric power generated by the hydraulic turbine generator set can also be used as a standby power supply of the power plant.
Drawings
To more clearly illustrate the technical solutions of the embodiments of the present application, the drawings of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description only relate to some embodiments of the present application and are not limiting on the present application.
FIG. 1 is a block diagram of a hydraulic turbine power generation system for redundant flow energy recovery according to an embodiment of the present application.
FIG. 2 is a block diagram of a hydraulic turbine power generation control system for redundant flow energy recovery according to an embodiment of the present application.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the drawings of the embodiments of the present application. It should be apparent that the embodiments described are some, but not all embodiments of the present application. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the application without any inventive step, are within the scope of protection of the application.
Unless defined otherwise, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this application belongs. The use of "first," "second," and similar terms in the description and claims of this patent application do not denote any order, quantity, or importance, but rather the terms are used to distinguish one element from another. Also, the use of the terms "a" or "an" and the like do not denote a limitation of quantity, but rather denote the presence of at least one.
Hereinafter, embodiments of the present application are described in detail with reference to the accompanying drawings.
FIG. 1 is a block diagram of a hydraulic turbine power generation system for redundant flow energy recovery according to an embodiment of the present application.
As shown in fig. 1, according to one aspect of the present application, a hydraulic turbine power generation system for redundant flow energy recovery is provided, including a boiler feed water pump E2, a hydraulic turbine generator set, and a deaerator E1.
The boiler feedwater pump E2 includes an inlet and an outlet. The boiler feed water pump E2 supplies the liquid working medium to the power plant boiler through its outlet at a predetermined head and flow rate.
The power plant referred to herein is a thermal power plant or a thermal power plant in the conventional sense, i.e., coal, oil (heavy oil), gas (coal gas, biogas, carbon-containing mixed gas), and domestic garbage are used as fuel, and a boiler is used to heat a working medium and drive a turbine to drive a generator to generate electricity. The working medium is referred to herein as treated water or a mixture of water and a treatment agent, and thus the working medium may also be referred to herein as water.
According to embodiments of the application, the boiler feedwater pump E2 may be a multi-stage centrifugal impeller tandem combination feedwater pump.
According to embodiments of the application, the power plant boiler E3 may provide steam power for a peaking turbine generator set. For peak shaving power plants, as known to those skilled in the art, the amount of power generated by the generator sets of the power plant is distributed by scheduling according to the power usage of the power grid. In particular, at peak and valley of power consumption (so-called deep peak shaving), the amount of water supply required by the boiler E3 varies with the amount of power generated, but the follow-up operation change of the boiler feed water pump E2 has a certain delay, and a certain amount of redundant flow is inevitably generated between the boiler feed water pump D2 and the boiler E3 under a certain operation condition by comprehensively considering the characteristics of the boiler E3 and the boiler feed water pump D2.
The hydraulic turbine generator set comprises a turbine E4, a generator E5 and a coupling for connecting the turbine E4 and the generator E5.
Turbine E4, also referred to herein as a hydraulic turbine, includes an inlet, an outlet, an impeller, and a shaft (not shown in detail), the inlet of turbine E4 being connected in fluid communication with the outlet of boiler feed pump E2. According to an embodiment of the present application, connecting the inlet of the turbine in fluid communication with the outlet of the boiler feedwater pump E2 may include a third line T3 and a pressure regulating valve V6 and gate valve V7 disposed on the third line T3. The pressure regulating valve V6 may be an electrically operated pressure regulating valve that opens and closes at a predetermined pressure as commanded by the control system. For example, when the outlet pressure of boiler feed water pump E2 rises to a first predetermined pressure, gate valve V7 opens to open third line T3 from the outlet of boiler feed water pump E2 to the inlet of turbine E4, so as to supply working medium to turbine E4, and the opening of pressure regulating valve V6 is adjusted to ensure that turbine E4 operates at the rated speed of generator E5. When the outlet pressure of boiler feed water pump E2 continues to rise to the second predetermined pressure, gate valve V7 closes, shutting off third line T3 from the outlet of boiler feed water pump E2 to the inlet of turbine E4, and effecting a stop in the supply of working medium to turbine E4.
According to embodiments of the present application, turbine E4 may include a plurality of impellers assembled in coaxial series that each absorb pressure energy of a working medium flowing therethrough and convert the pressure energy into mechanical energy that rotates itself to drive the main shaft of turbine E4 to rotate at high speeds, e.g., 3600rpm, 3000rpm, 1500rpm, and others as desired by those skilled in the art. Details of the turbine E4 will be described later.
The rotating shaft of the generator E5 is connected with the rotating shaft of the turbine E4 through a coupler. The connection of the rotating shaft of the generator E5 and the rotating shaft of the turbine E4 can be a rigid connection or a coupling connection. The rotational speed of the generator E5 and the turbine E4 may be synchronous rotational speed, for example 3000 rpm. However, the embodiment of the present invention is not limited thereto, and the rotation speed of the generator E5 and the turbine E4 may be 1500rpm or 3600rpm, or any suitable rotation speed, which can be determined by a person skilled in the art according to the corresponding relationship between the rotation speed and the pole pair number according to actual needs. Details of the generator E5 will be described later.
An oxygen scavenger E1 includes a plurality of working medium inlets, a working medium outlet, and at least one exhaust port (not shown in detail). As shown in FIG. 1, at least one of the plurality of working medium inlets is coupled in fluid communication with an outlet of turbine E4, and a working medium outlet of deaerator E1 is coupled in fluid communication with an inlet of boiler feedwater pump E2. According to an embodiment of the present application, the connection of at least one of the plurality of working medium inlets in fluid communication with the outlet of the turbine may comprise a fifth line T5 and an isolation valve V8 and a check valve V9 disposed on the fifth line T5. According to an embodiment of the present application, the working medium outlet of the deaerator E1 may be connected in fluid communication with an inlet of the boiler feed water pump E2, which may include a first line T1, and a pressure sensor PT, a gate valve V1, and a flow measuring device SG1, which are sequentially disposed on the first line T1.
According to the actual needs of the power grid, under the preset working condition of a steam turbine generator unit of the power plant, the turbine receives the working medium with preset redundant flow from a boiler feed water pump E2, and absorbs the pressure energy of the working medium to drive the rotating shaft of the turbine and drive the rotating shaft of the generator to rotate so as to generate power. The turbine generates electricity only with a predetermined redundant flow of boiler feed water pump E2.
According to an embodiment of the present application, the hydraulic turbine power generation system for redundant flow energy recovery may further include a main high pressure pipeline T4 leading from an outlet of the boiler feed water pump E2 to the boiler, and a check valve V10, a gate valve V11, and a flow measuring device SG2 sequentially disposed on the main high pressure pipeline T4. The main high pressure conduit T4 is the main line connecting the boiler feed pump E2 to the genset boiler. The hydraulic turbine power generation system for redundant flow energy recovery according to the embodiments of the present application is subject to and serves the needs of the power generation operation of the turbine-generator set of the power plant.
According to embodiments of the present application, the hydraulic turbine power generation system for redundant flow energy recovery may further include a boiler economizer E3, and the main pipeline T4 may lead to the boiler through the boiler economizer E3. The boiler economizer E3 is used for recycling waste heat in a flue at the front end of the boiler and also used for preheating water supplied to the front end of the boiler.
According to an embodiment of the present application, the hydraulic turbine power generation system for redundant flow energy recovery may further include a second line T2 fluidly connecting an outlet of the boiler feed water pump E2 and one of the plurality of working medium inlets of the deaerator E1, and a recirculation front isolation valve V2, a recirculation valve V3, a recirculation rear isolation valve V4, and a check valve V5 disposed on the second line T2. As mentioned above, when the boiler feed water pump E2 is in the working conditions of starting, stopping and quick adjustment, under the control of the control system, the recirculation valve V3 is opened, and when the opening degree of the pressure reducing valve V6 is adjusted, the turbine E4 still cannot operate in the working condition of the rated rotating speed of the generator E5, the recirculation valve V3 also needs to be opened, and the redundant flow flows back to the deaerator after being reduced in pressure by the recirculation valve V3. During this time, the recirculation valve V3 is carrying a large pressure differential, such as about 17mpa, which consumes a large amount of pressure energy. Of course, this is also an important guarantee that boiler feed water pumps and boilers will operate properly without causing an accidental shutdown.
According to the embodiment of the application, the power generated by the hydraulic turbine generator set can be merged into a service power grid through a transformer. However, embodiments of the present application are not limited thereto, and the electricity generated by the hydraulic turbine generator set may also be incorporated into the grid (national grid) through the transmission and transformation circuit. When the electric power generated by the hydraulic turbine generator set is merged into the service power grid, the electric power demand of the power plant on the power grid can be greatly reduced, and in addition, the hydraulic turbine generator set can also be used as a standby power supply for service power of the power plant. In this case, the dependence of the auxiliary standby power supply on the diesel generator set can be reduced.
According to an embodiment of the application, a hydraulic turbine power generation system for redundant flow energy recovery has a first operating mode, a second operating mode, and a third operating mode under different operating conditions, the first to third operating modes being switched by valve opening/closing in the system.
According to an embodiment of the application, in the first mode of operation, the boiler feed water pump E2 delivers working medium only to the power plant boiler E3; in the second operation mode, the pressure regulating valve V7 on the third pipeline is closed, the recirculation valve V3 on the second pipeline T2 is opened, the boiler feed water pump E2 can deliver the working medium to the power plant boiler E3, and meanwhile, the safe and stable operation of the boiler feed water pump can be maintained by shunting partial flow through the recirculation valve V3 on the second pipeline T3; in the third operating mode, the pressure regulating valve V7 on the third line T3 is opened, the recirculation valve V3 on the second line T2 is closed, and the boiler feed water pump E2 can supply the working medium to the power plant boiler E3, and at the same time, can supply a redundant flow of the working medium to the turbine E4 through the third line T3 and drive the generator E5 to generate electricity to recover the pressure energy of the working medium.
The significance and benefits of a hydraulic turbine power generation system for redundant flow energy recovery according to an embodiment of the present application are described below with reference to examples.
TABLE 1 summary table of actual running conditions of steam turbine generator units in 1000MW power plant
TABLE 2 operating law for opening recirculation valve of feed pump
TABLE 3 energy recovery effect economic benefit comparison
And (4) conclusion: the design parameters listed in table 3 are averaged to make a budget, and one unit can save about 180 ten thousand yuan of electricity per year.
FIG. 2 is a block diagram of a hydraulic turbine power generation control system for redundant flow energy recovery according to an embodiment of the present application.
As shown in FIG. 2, according to another aspect of the present application, there is provided a control system of a hydraulic turbine power generation system for redundant flow energy recovery, the hydraulic turbine power generation system for redundant flow energy recovery including a deaerator E1 collecting and deaerating each path of working medium, a boiler feed water pump E2 supplying the working medium to a power plant boiler E3, a hydraulic turbine generator set E4 using a redundant flow of the boiler feed water pump E2, E5, a recirculation valve V3 for overpressure protection, and a first line T1 connecting an outlet of the deaerator E1 to an inlet of the boiler feed water pump E2, a second line T2 connecting an outlet of the boiler feed water pump E2 to an inlet of the deaerator E1 via the recirculation valve V3, a third line T3 connecting an outlet of the boiler feed water pump E2 to inlets of the hydraulic turbine generator sets E4, E5, a fourth line T4 connecting an outlet of the boiler feed water pump E2 to a boiler E3, A fifth line T5 connecting the outlet of the hydraulic turbine generator set E4, E5 to the inlet of a deaerator E1, the control system comprising: the distributed computer controller DCS sends a control signal to the user side based on the input signal and a preset algorithm and is communicated with a main control room of the power plant; and a pressure transmitter PT3 for outputting pressure signal of the outlet of the boiler feed water pump to the distributed computer controller DCS. The distributed computer controller DCS receives a pressure signal of an outlet of the boiler feed water pump from the pressure transmitter PT3, divides the received pressure signal of the outlet of the boiler feed water pump into three operation modes, i.e., a first operation mode, a second operation mode, and a third operation mode, and the first to third operation modes are switched by opening/closing a valve in the system. The distributed computer controller DCS conducts the third pipeline only in the third operation mode and operates the hydraulic turbine generator set to generate power.
According to an embodiment of the present application, the control system of the hydraulic turbine power generation system for redundant flow energy recovery may further include a first pressure transmitter PT1 disposed at an outlet of the deaerator E1, a second pressure transmitter PT2 disposed at an inlet of the boiler feed water pump E2, a fourth pressure transmitter PT4 disposed at an inlet of the hydraulic turbine, a fifth pressure transmitter PT5 disposed at an outlet of the hydraulic turbine, and a sixth pressure transmitter PT6 disposed at an inlet of the power plant boiler. The distributed computer controller DCS receives the pressure signals from the pressure transmitters PT1, PT2, PT4, PT5 and PT6, and combines the pressure signals from the pressure transmitter PT3 to comprehensively judge the operation condition of the hydraulic turbine power generation system for redundant flow energy recovery according to a preset algorithm, and determines the next operation step of the hydraulic turbine power generation system.
According to an embodiment of the application, the first operation mode may be an operation mode of an outlet pressure of the boiler feed water pump when a load of the power plant steam turbine generator unit is above 70% of a design load, the second operation mode may be an operation mode of an outlet pressure of the boiler feed water pump when a load of the power plant steam turbine generator unit is 60% to 70% of the design load, the third operation mode may be an operation mode of a load of the power plant steam turbine generator unit fluctuating around 40% to 50% of the design load, and the third operation mode may further include an operation mode of deep peak shaving to lower that may occur according to a schedule of the power grid.
According to an embodiment of the present application, the control system of the hydraulic turbine power generation system for redundant flow energy recovery may further include a pressure regulating valve V6 and a gate valve V7 provided on the third line T3, the gate valve V7 and the recirculation valve V3 being closed in the first operation mode; in the second operating mode, recirculation valve V3 is open and gate valve V7 is closed; in the third operation mode, the pressure regulating valve V6 and the gate valve V7 are opened, and the recirculation valve V3 is closed.
According to an embodiment of the present application, the control system of the hydraulic turbine power generation system for redundant flow energy recovery may further include a flow measurement device SG1 provided at an inlet of the boiler feed water pump E2 and a flow measurement device SG2 provided at an inlet of the power plant boiler E3.
According to an embodiment of the present application, the control system of the hydraulic turbine power generation system for redundant flow energy recovery may further comprise differential pressure transmitters DPT1, DPT2 disposed at both ends of the flow measuring devices SG1, SG2, respectively, and the differential pressure signals generated by the differential pressure transmitters DPT1, DPT2 are sent to the distributed computer controller DCS and make flow distribution calculations.
According to an embodiment of the present application, in the third mode of operation, the redundant flow of the third line is equal to the difference between the flows measured by flow measuring devices SG1 and SG 2.
According to an embodiment of the present application, the control system of the hydraulic turbine power generation system for redundant flow energy recovery may further comprise a rotational speed measuring probe SE1, SE2, SE3 for monitoring the rotational speed of the hydraulic turbine, the distributed computer controller DCS controls the pressure regulating valve V6 to increase the opening when the rotational speed of the hydraulic turbine E4 is lower than the rated rotational speed of the generator E5, the distributed computer controller DCS controls the pressure regulating valve V6 to decrease the opening when the rotational speed of the hydraulic turbine E4 is higher than the rated rotational speed of the generator E5, and closes the gate valve V7 and opens the recirculation valve V3 when the rotational speed of the hydraulic turbine E4 is higher or lower than the rated rotational speed of the generator E5 and the opening of the pressure regulating valve V6 is invalid.
According to an embodiment of the application, the distributed computer controller DCS may be a subsystem of a main control room of the power plant, in any case, the distributed computer controller DCS operates under the main control room of the power plant.
In the following, design parameters and control requirements of a control system of a hydraulic turbine power generation system for redundant flow energy recovery are described by taking a 1000MW steam turbine generator set configured with a 100% capacity boiler feed water pump as an example.
The steam turbine generator unit operates in a load range of 400MW to 1000MW, the annual average load rate is 60%, the peak period power demand vigorous load rate is kept above 80%, the valley period power demand vigorous load rate is basically maintained to be 40% in load rate operation, the turbine generator unit is designed to be the highest in efficiency according to the boiler 40% in load rate, and the estimated annual operation time is 3000 h.
The inlet side of the feed water pump is provided with a flow measuring device SG1, the inlet side of the boiler is provided with a flow measuring device SG2, and the recirculation flow (pipeline T2) and the flow (pipeline T3) of the turbine generator set are the difference value between SG1 and SG 2.
And the outlet of the deaerator, the inlet and outlet of the feed pump, the inlet and outlet of the turbine and the inlet of the boiler are respectively provided with pressure detection PT 1-PT 6.
The recirculation valve V3 has a quick opening function, the gate valve V7 has a quick closing function, and the isolation valve V2, the isolation valve V4 and the isolation valve V8 are normally open.
The flow and the pressure of the medium required by the boiler E3 are determined by the load of the power grid, and the requirement is met by adjusting the opening degree of the valve V11 and the rotating speed of the feed water pump E2.
When the unit is about to start, stop and rapidly reduce the load, the recirculation valve V3 is fully opened, the gate valve V7 is fully closed, after the standby unit runs stably, the flow of the feed pump, namely the value of SG1 is larger than the minimum flow value of the feed pump within a certain range, and the recirculation valve V3 is slowly closed.
When the load of the turbine generator set is about 400MW to 500MW in operation, the turbine generator set is put into operation, the gate valve V7 and the pressure regulating valve V6 are opened, the recirculation valve V3 is closed, redundant high-pressure medium enters a turbine runner through a turbine inlet, low-pressure medium returns to a deaerator E1 through a turbine outlet after the turbine is driven to work, and the turbine drives the generator to work through a coupler. When the rotating speed of the turbine is higher than the working rotating speed of a generator, the opening degrees of a pressure regulating valve V6 and a gate valve V7 are reduced, and if the opening degrees are still not met, a recirculation valve V3 is opened properly; when the rotating speed of the turbine is higher than the safe rotating speed of the generator under special conditions, quickly closing the valve V7 and quickly opening the valve V3; when the rotating speed of the turbine is lower than the working speed of the generator, the gate valve V7 and the pressure regulating valve V6 are opened to full opening, and the recirculation valve V3 is regulated to full closing, so that the rotating speed of the turbine is ensured to be in the working range of the generator.
When the load is at 600MW and above, the turbo-generator is switched out, closing gate valve V7 and recirculation V3.
Compared with the prior art, the embodiment of the application can at least realize the following beneficial effects:
the hydraulic turbine power generation system for redundant flow energy recovery comprises a set of turbine generator set connected between an outlet of a boiler feed water pump and an inlet of a deaerator, wherein the turbine receives working media with preset redundant flow from the boiler feed water pump, absorbs pressure energy of the working media to drive a rotating shaft of the turbine and drive the rotating shaft of the generator to rotate so as to generate power, and the turbine only generates power by using the preset redundant flow of the boiler feed water pump. The recoverable redundant flow energy of the hydraulic turbine power generation system for recovering the redundant flow energy is huge, and by taking a 1000MW power generation unit as an example, the maximum recoverable energy per hour is 2300kW, and the annual energy generation amount is about 690 ten thousand kWH, so that the hydraulic turbine power generation system has a good energy-saving effect. If the energy is not recovered, the redundant flow flows back to the deaerator after being decompressed by the recirculation valve, the burden is increased on the recirculation valve, the abrasion is accelerated, the working medium is vaporized by the recirculation valve in the decompression process, the working burden of the deaerator is increased, and the heat emission generated in the decompression process is pollution to the ambient air. In addition, because the turbine absorbs redundant flow, the deterioration of the operation condition of the boiler feed pump can be reduced when the turbo-generator set operates at low load, namely, the flow of the boiler feed pump is properly increased under the condition that the outlet pressure is kept in a reasonable range, so that the boiler feed pump can be kept to operate under a better condition, and the energy consumed by the boiler feed pump can be completely recovered and compensated in the hydraulic turbo-generator set. The electric power generated by the hydraulic turbine generator set can be directly merged into the auxiliary power grid of the power plant after being transformed by the transformer, so that the electric power consumption of the power plant to the national power grid is reduced, and meanwhile, the electric power generated by the hydraulic turbine generator set can also be used as a standby power supply of the power plant.
The above description is only an exemplary embodiment of the present application and is not intended to limit the scope of the present application, which is defined by the appended claims.
Claims (15)
1. A hydraulic turbine power generation system for redundant flow energy recovery, comprising:
a boiler feed water pump (E2) comprising an inlet and an outlet through which a liquid working medium is provided to the power plant boiler (E3) at a predetermined head and flow rate;
a turbine (E4) comprising an inlet, an outlet, an impeller and a shaft, the inlet of the turbine (E4) being connected in fluid communication with the outlet of the boiler feedwater pump (E2);
a generator (E5), wherein the rotating shaft of the generator (E5) is connected with the rotating shaft of the turbine through a coupling;
a deaerator (E1) including a plurality of working medium inlets, a working medium outlet, and at least one exhaust, at least one of the plurality of working medium inlets being coupled in fluid communication with an outlet of the turbine (E4), a working medium outlet of the deaerator (E1) being coupled in fluid communication with an inlet of the boiler feedwater pump (E2),
wherein the turbine (E4) receives a preset redundant flow of working medium from the boiler feed water pump (E2), absorbs the pressure energy of the working medium to drive the rotating shaft of the turbine (E4) and drive the rotating shaft of the generator (E5) to rotate so as to generate electricity, and
wherein the turbine (E4) generates electricity using only a predetermined redundant flow of the boiler feedwater pump (E2).
2. The hydraulic turbine power generation system for redundant flow energy recovery of claim 1, further comprising a main high pressure conduit (T4) leading from an outlet of the boiler feed water pump (E2) to a boiler (E3), and a check valve (V10), a gate valve (V11), a flow measuring device (SG2) sequentially disposed on the main high pressure conduit (T4).
3. The hydraulic turbine power generation system for redundant flow energy recovery of claim 2 further including a boiler economizer and said main conduit (T4) leads to a boiler (E3) through said boiler economizer.
4. The hydraulic turbine power generation system for redundant flow energy recovery of claim 2, wherein the working medium outlet of the deaerator (E1) is connected in fluid communication with the inlet of the boiler feed water pump (E2) and comprises a first line (T1) and a pressure sensor (PT), a gate valve (V1), a flow measuring device (SG1) sequentially disposed on the first line (T1).
5. The hydraulic turbine power generation system for redundant flow energy recovery of claim 4, wherein said turbine (E4) inlet is connected in fluid communication with said boiler feed water pump (E2) outlet and includes a third line (T3) and a pressure regulating valve (V6) and gate valve (V7) disposed on said third line (T3).
6. The hydraulic turbine power generation system for redundant flow energy recovery of claim 5, wherein at least one of said plurality of working medium inlets is connected in fluid communication with an outlet of said turbine (E4) and includes a fifth line (T5) and an isolation valve (V8) and a check valve (V9) disposed on said fifth line (T5).
7. The hydraulic turbine power generation system for redundant flow energy recovery of claim 6, further comprising a second line (T2) fluidly connecting an outlet of said boiler feedwater pump (E2) and one of said plurality of working medium inlets of said deaerator (E1), and a recirculation front isolation valve (V2), a recirculation valve (V3), a recirculation rear isolation valve (V4), a check valve (V5) disposed on said second line (T2).
8. The hydraulic turbine power generation system for redundant flow energy recovery of claim 1, wherein said boiler feedwater pump (E2) is a multi-stage centrifugal impeller tandem combination feedwater pump.
9. The hydraulic turbine power generation system for redundant flow energy recovery of claim 1, wherein the power generated by the generator is coupled to a utility grid through a transformer.
10. The hydraulic turbine power generation system for redundant flow energy recovery of claim 1, wherein the power plant boiler (E3) provides steam power to a peaking turbine generator set.
11. The hydraulic turbine power generation system for redundant flow energy recovery of claim 1, wherein the working medium is treated water and a necessary chemical dissolved in the water.
12. The hydraulic turbine power generation system for redundant flow energy recovery of claim 7, wherein the hydraulic turbine power generation system has a first mode of operation, a second mode of operation, and a third mode of operation under different operating conditions, the first through third modes of operation being switched by valve opening/closing in the system.
13. The hydraulic turbine power generation system for redundant flow energy recovery of claim 12, wherein in the first mode of operation, the boiler feed water pump (E2) delivers working medium only to a power plant boiler (E3), the gate valve (V7) on the third line (T3) is closed, and the recirculation valve (V3) on the second line (T2) is closed.
14. The hydraulic turbine power generation system for redundant flow energy recovery of claim 12, wherein in said second mode of operation, a gate valve (V7) on said third line (T3) is closed and a recirculation valve (V3) on said second line (T2) is opened, said boiler feed water pump (E2) delivering working medium to a power plant boiler (E3) while maintaining safe and stable operation of the boiler feed water pump (E2) by diverting a portion of the flow through the recirculation valve (V3) on said second line (T2).
15. The hydraulic turbine power generation system for redundant flow energy recovery of claim 12, wherein in the third mode of operation, the pressure regulating valve (V6) and gate valve (V7) on the third line (T3) are opened, and the boiler feed water pump (E2) delivers working medium to the power plant boiler (E3) while supplying redundant working medium to the turbine (E4) through the third line (T3) and driving the generator (E5) to generate electricity to recover working medium pressure energy.
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| CN202210527368.8A CN115095393A (en) | 2022-05-16 | 2022-05-16 | Hydraulic turbine power generation system for redundant flow energy recovery |
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