CN113513746A - Method for determining optimized operation mode of closed circulating water system of thermal power plant - Google Patents

Method for determining optimized operation mode of closed circulating water system of thermal power plant Download PDF

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CN113513746A
CN113513746A CN202110452038.2A CN202110452038A CN113513746A CN 113513746 A CN113513746 A CN 113513746A CN 202110452038 A CN202110452038 A CN 202110452038A CN 113513746 A CN113513746 A CN 113513746A
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circulating water
water pump
temperature
unit
operation mode
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CN113513746B (en
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徐钟宇
阮圣奇
吴仲
陈开峰
宋勇
邵飞
蒋怀锋
徐搏超
李强
李敬豪
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Datang Boiler Pressure Vessel Examination Center Co Ltd
East China Electric Power Test Institute of China Datang Corp Science and Technology Research Institute Co Ltd
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Datang Boiler Pressure Vessel Examination Center Co Ltd
East China Electric Power Test Institute of China Datang Corp Science and Technology Research Institute Co Ltd
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    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22STEAM GENERATION
    • F22DPREHEATING, 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
    • F22D5/00Controlling water feed or water level; Automatic water feeding or water-level regulators
    • F22D5/26Automatic feed-control systems
    • F22D5/32Automatic feed-control systems influencing the speed or delivery pressure of the feed pumps

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Abstract

The invention provides a method for determining an optimized operation mode of a closed circulating water system of a thermal power plant, which comprises the following steps: acquiring the variation of the water temperature of the cooling tower when the operation mode of the circulating water pump is switched; b: acquiring characteristic parameters and curves of a condenser; c: acquiring unit load, a circulating water pump operation mode and circulating water inlet temperature; d: changing the running mode of the circulating water pump, and determining the temperature variation and the power consumption of the circulating water pump; e: calculating the backpressure of the steam turbine set, calculating the power of the steam turbine according to the backpressure, and calculating the net output of the steam turbine set according to the power; f: and taking the condition of the maximum net output as the optimal operation mode of the circulating water pump in the current state. The invention has the advantages that: the influence of temperature change is compensated in calculation so as to obtain accurate unit backpressure, improve the accuracy of results, accurately determine an optimal operation mode, improve the optimization effect and improve the economical efficiency of unit operation.

Description

Method for determining optimized operation mode of closed circulating water system of thermal power plant
Technical Field
The invention relates to the technical field of the optimized operation of a closed circulating water system of a thermal power plant, in particular to a method for determining the optimized operation mode of the closed circulating water system of the thermal power plant.
Background
The optimization operation of a circulating water pump in a closed circulating cooling water system of a thermal power plant is an important link for reducing the heat consumption of unit power generation. In a closed circulating cooling water system, a circulating water pump continuously applies work to enable cooling water to circulate between a condenser and a cooling tower, so that the circulating water pump becomes one of devices with higher power consumption in a thermal power plant, the consumed power accounts for 1% -1.5% of the total generated energy, and the operating mode of the circulating water pump has larger influence on the steam exhaust pressure of a steam turbine and the power plant consumption index, so that the research and the improvement of the operating mode of the circulating water pump have important significance on saving the power plant and improving the operating economy of the power plant.
Under the condition of certain unit load and circulating water inlet temperature, the steam turbine exhaust pressure changes along with the change of the circulating water flow, and the change of the circulating water flow is related to the power consumption of the circulating water pump. The flow rate of the circulating water is increased, the backpressure of the unit is reduced, the output of the unit is increased, and meanwhile, the power consumption of the circulating water pump is also increased. That is to say, the improvement of the condenser vacuum is at the cost of increasing the power consumption of the circulating water pump, and the circulating water pump is one of the major users of the service power, so when the circulating water quantity is increased, only if the output increment of the steam turbine is larger than the increment of the pump work, the increase of the circulating water flow is reasonable. Particularly, when the limit vacuum is realized, the circulating water flow is increased, so that the vacuum of the steam turbine is increased, the generated electricity is less than the electricity consumed by the circulating water pump, and the loss is not paid.
In the prior art, when a closed-cycle cooling water operation optimization test is performed, for example, a method for accurately determining an optimal combined operation scheme of a water pump unit of a circulating cooling water system of a power plant disclosed in the patent application with publication number CN104088771A, a comparison test of different circulating water pump operation modes (i.e., different circulating water quantities) is generally performed under the same turbine load and circulating water inlet temperature, and a circulating water pump operation mode in which the net output of the unit is increased to the maximum is found as an optimal operation mode. However, in the test process, after the flow rate of the circulating water is increased, the temperature of the water discharged from the cooling tower (i.e., the temperature of the water introduced into the cooling tower) is also increased, and if the temperature of the circulating water introduced into the condenser under different operating modes of the circulating water pump is regarded as a constant value, a large error is caused, and the effect of the optimization test is affected. On the other hand, in an attempt to theoretically calculate the change of the water temperature of the circulating water in the circulating water outlet tower in different circulating water pump operation modes, detailed cooling tower variable-working-condition thermodynamic calculation needs to be carried out, and meanwhile, thermodynamic characteristic data, resistance characteristic data and real-time environmental meteorological condition data need to be provided in the calculation process.
Disclosure of Invention
The invention aims to solve the technical problem of providing a method for determining the optimal operation mode of a circulating water pump under the condition of considering the change of the inlet water temperature of circulating water.
The invention solves the technical problems through the following technical scheme: a method for determining the optimized running mode of the closed circulating water system in thermal power plant includes
Step A: acquiring the variation of the water temperature of the cooling tower outlet when the operation modes of the circulating water pumps are switched;
and B: acquiring a cleaning coefficient of a condenser, a heat consumption characteristic curve of a steam turbine and a micro-increase output characteristic curve of the steam turbine;
and C: acquiring unit load, a circulating water pump operation mode and circulating water inlet temperature in the current state;
step D: changing the running mode of a circulating water pump, determining the temperature of the water discharged from the cooling tower according to the step A, and calculating the power consumption of the circulating water pump in the running mode;
step E: calculating the backpressure of the steam turbine set according to the inlet water temperature of circulating water, the flow rate of the circulating water and a cleaning coefficient, calculating the power of a steam turbine according to the backpressure, and calculating the net increase force of the current state of the steam turbine set according to the power of the steam turbine and the power consumption of a circulating water pump;
step F: and traversing different running modes of the circulating water pump, and taking the condition of the maximum net output as the best running mode of the circulating water pump in the current state.
The method considers the influence of the operation mode of the circulating water pump on the water temperature of the cooling tower outlet, compensates the influence of the temperature change in the calculation so as to obtain accurate unit backpressure, improves the accuracy of the result, can accurately determine the optimal operation mode, improves the optimization effect and improves the economical efficiency of unit operation.
Preferably, in the step a, the historical trend of the unit DCS is called, the trend of the change of the temperature of the water discharged from the tower after the operation modes of the circulating water pump are switched in daily operation is checked, and the change Δ t of the temperature of the water discharged from the tower of the cooling tower when the operation modes of different circulating water pumps are switched is obtained.
Preferably, in the step B, turbine thermal tests under different unit loads and different circulating water pump operation modes are performed to obtain a cleaning coefficient K of the condenser, a heat consumption characteristic curve of the turbine, and a micro output characteristic curve of the turbine.
Preferably, in step E, the turbine output after the back pressure change is obtained according to the micro output characteristic curve, and then the net output of the turbine set is:
ΔP=P′-W
wherein, the delta P is the net output of the unit; p' is the unit output after the backpressure changes, and is calculated by using a unit micro-output curve according to the current unit backpressure; w is the power consumption of the circulating water pump.
Preferably, the method for calculating the back pressure in step E is as follows:
firstly, calculating the condensation temperature of steam in a condenser:
ts=tw1+Δt+δt
Figure BDA0003039158880000031
Figure BDA0003039158880000032
wherein t issIs the condensation temperature, t, of the steam in the condenserw1The temperature of the circulating water inlet of the condenser is delta t, the temperature rise of the circulating water in the condenser is delta t, and the delta t is the end difference of the condenser; dcThe steam turbine exhaust steam quantity; h iscIs the specific enthalpy of steam turbine exhaust; h'cSpecific enthalpy of condensed water; dwIs the flow of circulating cooling water; cvThe specific heat capacity of cooling water; k is the heat exchange coefficient of the condenser; a is the heat exchange area of the condenser;
the relationship between the backpressure and the condensation temperature of steam in the condenser is as follows:
pk=f(ts)
wherein p iskIs the back pressure of the steam turbine, namely the exhaust pressure, and the unit is kPa; and considering that the partial pressure of the steam is equal to the backpressure of the turbine because the content of non-condensable gas in the condenser is very low, and obtaining the backpressure of the turbine by checking a steam characteristic chart according to the condensation temperature of the steam in the condenser.
Preferably, the method further comprises the step G:
and D, keeping the load of the unit unchanged, changing the temperature of the water discharged from the cooling tower, and repeating the steps D-F to obtain the optimal running modes of the circulating water pumps corresponding to different water inlet temperatures under the load.
Preferably, the method further comprises the step H: and G, changing the load of the unit, returning to the step G, and respectively obtaining the optimal running modes of the circulating water pump corresponding to different temperatures under different loads.
Preferably, the variation range of the inlet water temperature of the circulating water is 10-40 ℃, and the optimal operation mode of the circulating water pump is determined by taking values at intervals of 2 ℃.
Preferably, the variation range of the unit load is 40% -100%, and the optimal operation mode of the circulating water pump is determined by taking values at intervals of 5% or 10%.
The invention also provides a method for determining the optimized operation mode of the closed circulating water system of the thermal power plant, which is characterized by comprising the following steps of: comprises that
Step 1: acquiring the variation delta t of the water temperature of the cooling tower outlet when the operation modes of different circulating water pumps are switched according to DCS historical data;
step 2: carrying out turbine thermal tests under different unit loads and different circulating water pump operation modes, and obtaining a cleaning coefficient K of a condenser, a heat consumption characteristic curve of a turbine and a micro-increase output characteristic curve of the turbine;
and step 3: assuming that the load of the unit is 40% of rated load, and the inlet water temperature t0 of circulating water in a certain circulating water pump patrolling mode is 10 ℃, according to the temperature rise of the outlet water in different circulating water pump operation modes obtained in the step 1, the inlet water temperature of the circulating water corresponding to other circulating water pump operation modes can be known; calculating the unit net output power corresponding to different circulating water pump operation modes when the circulating water inlet temperature is 10 ℃ by using the condenser cleaning coefficient, the heat consumption characteristic curve of the steam turbine and the micro output characteristic curve of the steam turbine obtained in the step 2, and preferably selecting the maximum unit net output power and the circulating water pump operation mode corresponding to the maximum unit net output power as the optimal circulating water pump operation mode under the conditions of the unit load and the circulating water inlet temperature;
and 4, step 4: keeping the load of the unit unchanged at 40% of rated load, enabling the circulating water inlet temperature t0 to be 10+2i (i is 1, 2, 3, …) until the circulating water inlet temperature is 40 ℃, and traversing and calculating the corresponding optimal circulating water pump operation mode at each temperature when the circulating water temperature changes from 10 ℃ to 40 ℃;
and 5: and (4) repeating the step (3) and the step (4), traversing and calculating the optimal circulating water pump operation modes under different circulating water inlet temperatures when the unit load is respectively 50% of rated load, 60% of rated load, 70% of rated load, 80% of rated load, 90% of rated load and 100% of rated load, and intuitively representing the calculation result by a graph for guiding the circulating water optimization operation of the power plant.
The method for determining the optimized operation mode of the closed circulating water system of the thermal power plant has the advantages that: the influence of the running mode of the circulating water pump on the temperature of the tower outlet water of the cooling tower is considered, the influence of the temperature change is compensated in calculation, so that accurate unit backpressure is obtained, the accuracy of results is improved, the optimal running mode can be accurately determined, the optimization effect is improved, and the running economy of the unit is improved. The relation between the operation mode of the circulating water pump and the variation of the circulating water temperature is obtained through experiments or historical data, the result reliability is high, and the influence of accidental factors is avoided.
Drawings
Fig. 1 is a flowchart of a method for determining an optimal operation mode of a closed circulating water system of a thermal power plant according to an embodiment of the present invention.
Detailed Description
To make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention are described below in detail and completely with reference to the accompanying drawings, and it is apparent that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
As shown in fig. 1, the present embodiment provides a method for determining an optimal operation mode of a closed circulating water system of a thermal power plant, including:
step A: acquiring the variation of the temperature of water discharged from the cooling tower when the operation modes of the circulating water pumps are switched; the temperature of the water discharged from the cooling tower is the temperature of the water inlet of the circulating water, and the variation of the temperature can be obtained by testing through historical data of the unit or changing the operation mode of the unit.
The change amount delta t of the temperature of the inlet circulating water of the condenser when different circulating water pump operation modes are switched is obtained through DCS historical data, and the factor influencing the temperature of the tower water is known through theoretical analysis on the heat exchange principle of the cooling tower: the unit load; circulating water flow (different circulating water pump operation modes); ambient temperature, humidity; wind speed, wind direction, etc. Due to the fact that the switching time of the circulating water pump is short, other factors except the circulating water quantity are basically unchanged in the period, and the influence on the water temperature of the cooling tower outlet can be ignored. By adjusting the historical trend of the unit DCS, the change trend of the water temperature out of the tower after the operation modes of the circulating water pump are switched in daily operation is checked, the change quantity delta t of the circulating water temperature at the inlet of the condenser when the operation modes of different circulating water pumps are switched is obtained, and finally the obtained result refers to a table 1;
Figure BDA0003039158880000051
table 1: relation between unit operation mode and circulating water temperature variation
And B: acquiring a cleaning coefficient of a condenser, a heat consumption characteristic curve of a steam turbine and a micro-increase output characteristic curve of the steam turbine; the heat consumption characteristic curve is the relation between the unit load and the unit heat consumption, and the micro-output characteristic curve is the relation between the unit backpressure and the turbine power.
The characteristics can be obtained by performing thermal experiments on the steam turbine under the conditions of different unit loads and different running modes of the circulating water pump, and the specific method is the prior art in the field.
And C: acquiring unit load, a circulating water pump operation mode and circulating water inlet temperature in the current state;
step D: changing the running mode of a circulating water pump, determining the temperature of the water discharged from the cooling tower according to the step A, and calculating the power consumption of the circulating water pump in the running mode;
the change of the operation mode of the circulating water pump can be to change the number of the operation units of the circulating water pump or change the operation rotating speed, after the operation mode is changed, the flow rate of the circulating water is correspondingly changed, and at the moment, the temperature change quantity obtained in the step A and the relation between the operation modes can be obtained, so that the inlet water temperature of the circulating water after the operation mode is changed can be determined, and meanwhile, the power consumption and the flow rate of the circulating water pump can be directly determined according to the operation mode of the circulating water pump.
Step E: calculating the backpressure of the steam turbine set according to the tower outlet water temperature of the cooling tower, the circulating water flow and the cleaning coefficient, calculating the power of the steam turbine according to the backpressure, and calculating the net increase force of the current state of the steam turbine set according to the power of the steam turbine and the power consumption of the circulating water pump;
the backpressure calculating method in the step E comprises the following steps:
firstly, calculating the condensation temperature of steam in a condenser:
ts=tw1+Δt+δt
Figure BDA0003039158880000052
Figure BDA0003039158880000053
wherein t issIs the condensation temperature, t, of the steam in the condenserw1The temperature of the circulating water inlet of the condenser is delta t, the temperature rise of the circulating water in the condenser is delta t, and the delta t is the end difference of the condenser; dcThe steam turbine exhaust steam quantity; h iscIs the specific enthalpy of steam turbine exhaust; h'cSpecific enthalpy of condensed water; dwIs the flow of circulating cooling water; cvThe specific heat capacity of cooling water; k is the heat exchange coefficient of the condenser; a is the heat exchange area of the condenser;
the relationship between the backpressure and the condensation temperature of steam in the condenser is as follows:
pk=f(ts)
wherein p iskIs the back pressure of the steam turbine, namely the exhaust pressure, and the unit is kPa; and considering that the partial pressure of the steam is equal to the backpressure of the turbine because the content of non-condensable gas in the condenser is very low, and obtaining the backpressure of the turbine by checking a steam characteristic chart according to the condensation temperature of the steam in the condenser.
And obtaining the output of the steam turbine after the back pressure changes according to the micro-output characteristic curve, wherein the net output of the unit is as follows:
ΔP=P′-W
wherein, the delta P is the net output of the unit; p' is the unit output after the backpressure changes, and is calculated by using a unit micro-output curve according to the current unit backpressure; w is the power consumption of the circulating water pump.
Step F: traversing different circulating water pump operation modes, taking the condition of the maximum net output as the optimal operation mode of the circulating water pump in the current state, and indicating that the net output of the unit is maximum when the operation mode of the circulating water pump is adjusted to the optimal operation mode under the condition that the unit load, the operation mode of the circulating water pump and the circulating water inlet temperature are consistent with the initial adjustment.
Further, also comprises
Step G: keeping the load of the unit unchanged, changing the temperature of the water discharged from the cooling tower, and repeating the steps D-F to obtain the optimal operation modes of the circulating water pump corresponding to different water inlet temperatures under the load;
step H: and G, changing the load of the unit, returning to the step G, and respectively obtaining the optimal running modes of the circulating water pump corresponding to different temperatures under different loads.
In the preferred embodiment, the variation range of the temperature of the water discharged from the cooling tower is 10-40 ℃, and the optimal operation mode of the circulating water pump is determined by taking values at intervals of 2 ℃; the variation range of the unit load is 40% -100%, and the optimal operation mode of the circulating water pump is determined at intervals of 5% or 10%.
By the method, the table of the optimal operation modes under different temperatures and different unit loads can be obtained, so that the optimal operation mode of the circulating water pump can be quickly determined when the unit is in different states, and certainly, if the initial operation mode of the unit is not consistent with the initial operation mode in the table, calculation and determination are still required through the steps C-F.
The influence of the running mode of the circulating water pump on the temperature of the tower outlet water of the cooling tower is considered in the embodiment, the influence is compensated in calculation through collecting historical data or unit experiments, so that accurate unit backpressure is obtained, the accuracy of results is improved, the optimal running mode can be accurately determined, the optimization effect is improved, and the economical efficiency of unit running is improved.
The implementation also provides a method for determining the optimized operation mode of the closed circulating water system of the thermal power plant, which comprises the following steps
Step 1: acquiring the variation delta t of the water temperature of the cooling tower outlet when the operation modes of different circulating water pumps are switched according to DCS historical data;
step 2: carrying out turbine thermal tests under different unit loads and different circulating water pump operation modes, and obtaining a cleaning coefficient K of a condenser, a heat consumption characteristic curve of a turbine and a micro-increase output characteristic curve of the turbine;
and step 3: assuming that the load of the unit is 40% of rated load, and the inlet water temperature t0 of circulating water in a certain circulating water pump patrolling mode is 10 ℃, according to the temperature rise of the outlet water in different circulating water pump operation modes obtained in the step 1, the inlet water temperature of the circulating water corresponding to other circulating water pump operation modes can be known; calculating the unit net output power corresponding to different circulating water pump operation modes when the circulating water inlet temperature is 10 ℃ by using the condenser cleaning coefficient, the heat consumption characteristic curve of the steam turbine and the micro output characteristic curve of the steam turbine obtained in the step 2, and preferably selecting the maximum unit net output power and the circulating water pump operation mode corresponding to the maximum unit net output power as the optimal circulating water pump operation mode under the conditions of the unit load and the circulating water inlet temperature;
and 4, step 4: keeping the load of the unit unchanged at 40% of rated load, enabling the circulating water inlet temperature t0 to be 10+2i (i is 1, 2, 3, …) until the circulating water inlet temperature is 40 ℃, and traversing and calculating the corresponding optimal circulating water pump operation mode at each temperature when the circulating water temperature changes from 10 ℃ to 40 ℃;
and 5: and (4) repeating the step (3) and the step (4), traversing and calculating the optimal circulating water pump operation modes under different circulating water inlet temperatures when the unit load is respectively 50% of rated load, 60% of rated load, 70% of rated load, 80% of rated load, 90% of rated load and 100% of rated load, and intuitively representing the calculation result by a graph for guiding the circulating water optimization operation of the power plant.
The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present 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 solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims (10)

1. A method for determining an optimized operation mode of a closed circulating water system of a thermal power plant is characterized by comprising the following steps of: comprises that
Step A: acquiring the variation of the water temperature of the cooling tower outlet when the operation modes of the circulating water pumps are switched;
and B: acquiring a cleaning coefficient of a condenser, a heat consumption characteristic curve of a steam turbine and a micro-increase output characteristic curve of the steam turbine;
and C: acquiring unit load, a circulating water pump operation mode and circulating water inlet temperature in the current state;
step D: changing the running mode of a circulating water pump, determining the temperature of the water discharged from the cooling tower according to the step A, and calculating the power consumption of the circulating water pump in the running mode;
step E: calculating the backpressure of the steam turbine set according to the tower outlet water temperature of the cooling tower, the circulating water flow and the cleaning coefficient, calculating the power of the steam turbine according to the backpressure, and calculating the net increase force of the current state of the steam turbine set according to the power of the steam turbine and the power consumption of the circulating water pump;
step F: and traversing different running modes of the circulating water pump, and taking the condition of the maximum net output as the best running mode of the circulating water pump in the current state.
2. The method for determining the optimized operation mode of the closed circulating water system of the thermal power plant as claimed in claim 1, wherein the method comprises the following steps: and B, checking the change trend of the water temperature of the cooling tower after the operation modes of the circulating water pump are switched in daily operation by calling the historical trend of the DCS of the unit, and obtaining the change quantity delta t of the water temperature of the cooling tower when the operation modes of the circulating water pump are switched.
3. The method for determining the optimized operation mode of the closed circulating water system of the thermal power plant as claimed in claim 1, wherein the method comprises the following steps: and B, carrying out turbine thermal tests under different unit loads and different circulating water pump operation modes, and obtaining a cleaning coefficient K of the condenser, a heat consumption characteristic curve of the turbine and a micro-output characteristic curve of the turbine.
4. The method for determining the optimized operation mode of the closed circulating water system of the thermal power plant as claimed in claim 1, wherein the method comprises the following steps: and E, acquiring the output of the steam turbine after the back pressure is changed according to the micro output characteristic curve, wherein the net output of the unit is as follows:
ΔP=P′-W
wherein, the delta P is the net output of the unit; p' is the unit output after the backpressure changes, and is calculated by using a unit micro-output curve according to the current unit backpressure; w is the power consumption of the circulating water pump.
5. The method for determining the optimized operation mode of the closed circulating water system of the thermal power plant as claimed in claim 1, wherein the method comprises the following steps: the method for calculating the backpressure in the step E comprises the following steps:
firstly, calculating the condensation temperature of steam in a condenser:
ts=tw1+Δt+δt
Figure FDA0003039158870000011
Figure FDA0003039158870000012
wherein t issIs the condensation temperature, t, of the steam in the condenserw1The temperature of the circulating water inlet of the condenser is delta t, the temperature rise of the circulating water in the condenser is delta t, and the delta t is the end difference of the condenser; dcFor steam turbinesThe machine exhaust steam quantity; h iscIs the specific enthalpy of steam turbine exhaust; h'cSpecific enthalpy of condensed water; dwIs the flow of circulating cooling water; cvThe specific heat capacity of cooling water; k is the heat exchange coefficient of the condenser; a is the heat exchange area of the condenser;
the relationship between the backpressure and the condensation temperature of steam in the condenser is as follows:
pk=f(ts)
wherein p iskIs the back pressure of the steam turbine, namely the exhaust pressure, and the unit is kPa; and considering that the partial pressure of the steam is equal to the backpressure of the turbine because the content of non-condensable gas in the condenser is very low, and obtaining the backpressure of the turbine by checking a steam characteristic chart according to the condensation temperature of the steam in the condenser.
6. The method for determining the optimized operation mode of the closed circulating water system of the thermal power plant as claimed in claim 1, wherein the method comprises the following steps: further comprising the step G:
and D, keeping the load of the unit unchanged, changing the temperature of the water discharged from the cooling tower, and repeating the steps D-F to obtain the optimal running modes of the circulating water pumps corresponding to different water inlet temperatures under the load.
7. The method for determining the optimized operation mode of the closed circulating water system of the thermal power plant as claimed in claim 6, wherein the method comprises the following steps: further comprising the step H: and G, changing the load of the unit, returning to the step G, and respectively obtaining the optimal running modes of the circulating water pump corresponding to different temperatures under different loads.
8. The method for determining the optimized operation mode of the closed circulating water system of the thermal power plant as claimed in claim 6, wherein the method comprises the following steps: the variation range of the inlet water temperature of the circulating water is 10-40 ℃, and the optimal operation mode of the circulating water pump is determined by taking values at intervals of 2 ℃.
9. The method for determining the optimized operation mode of the closed circulating water system of the thermal power plant as claimed in claim 7, wherein the method comprises the following steps: the variation range of the unit load is 40% -100%, and the optimal operation mode of the circulating water pump is determined at intervals of 5% or 10%.
10. A method for determining an optimized operation mode of a closed circulating water system of a thermal power plant is characterized by comprising the following steps of: comprises that
Step 1: acquiring the variation delta t of the water temperature of the cooling tower outlet when the operation modes of different circulating water pumps are switched according to DCS historical data;
step 2: carrying out turbine thermal tests under different unit loads and different circulating water pump operation modes, and obtaining a cleaning coefficient K of a condenser, a heat consumption characteristic curve of a turbine and a micro-increase output characteristic curve of the turbine;
and step 3: assuming that the load of the unit is 40% of rated load, and the inlet water temperature t0 of circulating water in a certain circulating water pump patrolling mode is 10 ℃, according to the temperature rise of the outlet water in different circulating water pump operation modes obtained in the step 1, the inlet water temperature of the circulating water corresponding to other circulating water pump operation modes can be known; calculating the unit net output power corresponding to different circulating water pump operation modes when the circulating water inlet temperature is 10 ℃ by using the condenser cleaning coefficient, the heat consumption characteristic curve of the steam turbine and the micro output characteristic curve of the steam turbine obtained in the step 2, and preferably selecting the maximum unit net output power and the circulating water pump operation mode corresponding to the maximum unit net output power as the optimal circulating water pump operation mode under the conditions of the unit load and the circulating water inlet temperature;
and 4, step 4: keeping the load of the unit unchanged at 40% of rated load, enabling the circulating water inlet temperature t0 to be 10+2i (i is 1, 2, 3, …) until the circulating water inlet temperature is 40 ℃, and traversing and calculating the corresponding optimal circulating water pump operation mode at each temperature when the circulating water temperature changes from 10 ℃ to 40 ℃;
and 5: and (4) repeating the step (3) and the step (4), traversing and calculating the optimal circulating water pump operation modes under different circulating water inlet temperatures when the unit load is respectively 50% of rated load, 60% of rated load, 70% of rated load, 80% of rated load, 90% of rated load and 100% of rated load, and intuitively representing the calculation result by a graph for guiding the circulating water optimization operation of the power plant.
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113932855A (en) * 2021-10-28 2022-01-14 浙江浙能技术研究院有限公司 Method for measuring flow channeling in operation of expansion unit system of closed circulating water system of power plant

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102352780A (en) * 2011-06-30 2012-02-15 国电龙源电力技术工程有限责任公司 Optimal control method of cold end of thermal power generating unit
JP2013015276A (en) * 2011-07-05 2013-01-24 Toshiba Corp Device and method for controlling circulating water pump
CN103244397A (en) * 2013-05-09 2013-08-14 国家电网公司 Optimal operation control method for variable-frequency circulating water pump
CN104088771A (en) * 2014-06-30 2014-10-08 扬州大学 Accurate determination method of optimal water pump unit combination operation scheme of circulation cooling water system of power plant
CN106052418A (en) * 2016-06-29 2016-10-26 淄博环能海臣环保技术服务有限公司 On-off switchable air cooling and water cooling composite cooling tower for air cooling radiator and operation mode
CN112052570A (en) * 2020-08-24 2020-12-08 杭州电子科技大学 Economy backpressure optimization method of wet cooling unit of thermal power plant based on wolf algorithm
CN112096602A (en) * 2020-09-29 2020-12-18 国电华北电力有限公司廊坊热电厂 Method for automatically controlling frequency conversion circulating water pump set of wet cooling steam turbine power generation set
CN112431748A (en) * 2020-11-23 2021-03-02 西安热工研究院有限公司 Optimal operation method and system for circulation unit circulation pump based on condenser inlet water temperature

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102352780A (en) * 2011-06-30 2012-02-15 国电龙源电力技术工程有限责任公司 Optimal control method of cold end of thermal power generating unit
JP2013015276A (en) * 2011-07-05 2013-01-24 Toshiba Corp Device and method for controlling circulating water pump
CN103244397A (en) * 2013-05-09 2013-08-14 国家电网公司 Optimal operation control method for variable-frequency circulating water pump
CN104088771A (en) * 2014-06-30 2014-10-08 扬州大学 Accurate determination method of optimal water pump unit combination operation scheme of circulation cooling water system of power plant
CN106052418A (en) * 2016-06-29 2016-10-26 淄博环能海臣环保技术服务有限公司 On-off switchable air cooling and water cooling composite cooling tower for air cooling radiator and operation mode
CN112052570A (en) * 2020-08-24 2020-12-08 杭州电子科技大学 Economy backpressure optimization method of wet cooling unit of thermal power plant based on wolf algorithm
CN112096602A (en) * 2020-09-29 2020-12-18 国电华北电力有限公司廊坊热电厂 Method for automatically controlling frequency conversion circulating water pump set of wet cooling steam turbine power generation set
CN112431748A (en) * 2020-11-23 2021-03-02 西安热工研究院有限公司 Optimal operation method and system for circulation unit circulation pump based on condenser inlet water temperature

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
张玉等: "发电机组凝汽器背压的优化计算", 《上海理工大学学报》 *
曾德良等: "双压凝汽器闭式循环水系统的最优运行方式", 《热能动力工程》 *
王奔等: "燃煤电厂300 MW机组循环水系统运行优化研究", 《热能动力工程》 *
郑姗等: "火电厂闭式循环水系统变工况运行优化", 《动力工程学报》 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113932855A (en) * 2021-10-28 2022-01-14 浙江浙能技术研究院有限公司 Method for measuring flow channeling in operation of expansion unit system of closed circulating water system of power plant
CN113932855B (en) * 2021-10-28 2024-05-14 浙江浙能技术研究院有限公司 Method for measuring channeling flow during operation of expansion unit of closed circulating water system of power plant

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