Method for determining optimal operation frequency of cold end system of coal power unit and related device

Abstract

The invention discloses a method for determining the optimal operation frequency of a cold-end system of a coal-fired power generator set and a related device, and the method comprises the steps: determining an optimization target according to the capacity electricity price policy of a power grid and the coal consumption-power generation-self station service power correlation characteristics of the coal-fired power generator set; according to the thermodynamic cycle characteristics of the coal-fired power generation unit, the standard coal consumption consumed when the boiler needs to maintain the maximum output is obtained through testing; the optimal operation frequency of the circulating water pump is determined by changing the operation frequency of the circulating water pump, the circulating cooling water flow and the power consumption of the circulating water pump to optimize the target and the standard coal consumption. According to the method, the optimal operation frequency of the circulating water pump of the coal power unit is determined by changing the operation frequency of the variable-frequency circulating water pump of the cold-end system through a single-variable comparison optimization method and taking the maximum net profit increment as an optimization target. The method closely meets the profitability maximization requirement of the coal-fired power generation unit in a novel power system, assists transformation and high-quality development of coal power enterprises, and is wide in application prospect.

Description

Technical Field

[0001] This application belongs to the field of refined control of coal-fired wet-cooled generator sets adapting to the new power system, and particularly to the determination of the optimal operation mode of the cold-end system adapting to the capacity price trading rule. Specifically, it is a method for determining the optimal operation frequency of the cold-end system of a coal-fired power unit and related devices. Background Art

[0002] At present, the declaration of the generating capacity by coal-fired power enterprises and the recognition of the generating capacity by grid enterprises are the keys to the settlement of capacity electricity charges. A new power market system with efficient coordination such as the electricity energy market, capacity market, spot or ancillary service market is becoming increasingly mature. The operation and settlement rules of coal-fired power enterprises in the power market are changing. To adapt to these changes, coal-fired power should adjust its own operation mode. However, different markets have different focuses and significant changes in operation rules, so the optimal operation modes corresponding to different markets are not the same.

[0003] For the capacity price market, coal-fired power enterprises declare the maximum generating capacity, and grid enterprises verify the maximum generating capacity by calling the maximum generating output of coal-fired power enterprises. However, up to now, the refined operation of coal-fired power units has focused on optimizing the target of the lowest coal consumption with a fixed generating output or the maximum generating output with a fixed boiler evaporation capacity. For example:

[0004] The literature "Guo Jian, et al. Research on the operation optimization of the circulating water system of a 630MW coal-fired unit [J]. Thermal Turbine, 2022". Taking the open-circuit circulating water system of a certain 630MW coal-fired unit as the research object, an optimization scheduling model of the circulating water pump and a unit backpressure prediction model are established respectively. The optimal operation mode of the best circulating water pump under different electric loads and circulating water inlet temperatures is analyzed, and the accuracy of the optimization model is verified through historical operation data. The optimal operation mode of the circulating water pump at different circulating water temperatures in the full load section is studied to guide the scheduling of the circulating water pump during deep peak shaving of the unit. A real-time optimization scheduling system of the circulating water pump is developed, which gives the best operation mode of the circulating water pump under the current working conditions based on on-site real-time data, and provides guiding suggestions for the circulating water pump scheduling of on-site operators. The vacuum of the condenser is closely related to the circulating water flow rate, and the circulating water flow rate is determined by the number of operating circulating water pumps. During operation, the unit increases the circulating water flow rate to improve the vacuum. Although increasing the vacuum can increase the specific enthalpy drop of the steam turbine and increase the unit power, the power consumption of the circulating water pump also increases accordingly. The optimization target of this research is: the difference between the increment of the generating power of the steam turbine unit and the increment of the power consumption of the circulating water pump reaches the maximum, and the corresponding combination mode of the circulating water pumps is the best operation mode of the circulating water pump.

[0005] The literature "Niu Xiaochuan, et al. Optimization of Circulating Water Pump Operation Based on the Operating Income of Power Plants [J]. Thermal Power Generation, 2021" considered the dispatching control points and control methods of the actual output of the unit by the power grid company on the basis of the traditional optimization of circulating water pump operation, and concluded that after the power plant increased the circulating water pump, the lost was the electricity sent to the grid, and the saved was the raw coal arriving at the plant. It is necessary to comprehensively consider indicators such as the on-grid electricity price, the coal price arriving at the plant, the value-added tax rate, and the power supply coal consumption of the power plant, introduce the operating coefficient of the power plant, and correct the results of the optimized operation of the circulating water pump. Different operating coefficients of the power plant form different dividing lines for the operating modes of the circulating water pump, and new optimization results are obtained. This new optimization result can more truly reflect the revenue situation of the power plant and maximize the operating income of the power plant.

[0006] The literature "Cheng Dongtao, et al. Research on the Optimization of the Circulating Water Pump Operation of Steam Turbines Based on the Economic Value of Coal-fired Power [J]. Steam Turbine Technology, 2015" proposed an optimization theory based on the optimal economic value of coal and electricity by deeply analyzing the actual operating status of the unit and comprehensively considering the influence of coal price and electricity price on the optimization of circulating water pump operation, and carried out an example analysis on a 660MW unit. For the power grid dispatching mode in China mainly based on the generated electricity of the unit, determining the optimal operating mode of the circulating water pump by the optimal method of the economic value of coal and electricity can more truly and maximize the actual economic benefits of the unit. Operating optimization principle: Combining the main dispatching mode of China's power grid - based on the generated electricity of the unit, when the change in the operating mode of the circulating water pump brings about changes in the cooling water flow of the condenser and the back pressure of the steam turbine, since the generated electricity of the unit is controlled by the power grid dispatching and cannot be changed arbitrarily, at this time, the influence of the change in the back pressure of the steam turbine on the unit is mainly reflected in the changes in the heat consumption and coal consumption for power generation of the steam turbine. At the same time, the change in the power consumption of the circulating water pump brought about by the change in the operating mode of the circulating water pump directly affects the plant electricity consumption and the electricity sent to the grid of the unit. When the coal consumption economic value and the power consumption economic value corresponding to different operating modes of the circulating water pump are the smallest, it is the optimal operating back pressure of the steam turbine and the optimal operating mode of the circulating water pump.

[0007] Based on the above analysis, the optimization operations of existing research initially took the net output as the optimization target, and later, on the basis of the net output, the influence of coal consumption, etc. was added. However, essentially, it was still an optimization operation under the grid operation rules mainly based on electricity settlement. However, in the newly promulgated capacity tariff policy and the early medium- and long-term and power spot trading markets, the power generation power of coal-fired power is no longer a passive response, but can be actively declared. The corresponding settlement methods and electricity prices have changed greatly. Therefore, ignoring the unequal relationship between the power grid enterprise's electricity price for power generation capacity settlement and the coal-fired power enterprise's power generation cost price, and only using the thermal performance indicators of coal-fired generating units themselves, such as power generation output, as the optimization guidance cannot reflect the change in profitability, so it cannot be used as the refined operation guidance for coal-fired power enterprises under the new situation. Summary of the Invention

[0008] The purpose of this application is to solve the problems in the prior art, and provide a method and related device for determining the optimal operating frequency of the cold-end system of a coal-fired power unit. This application takes into account the settlement rules of the capacity price policy for the electricity price of coal-fired power enterprises, fixes the maximum output of the boiler, and uses the single-variable comparison and optimization method. By changing the operating frequency of the cold-end system, with the maximum net profit increment as the optimization goal, the optimal operating frequency of the cold-end system of a coal-fired wet-cooled generator set is determined.

[0009] To achieve the above purpose, this application adopts the following technical solutions:

[0010] In the first aspect, this application provides a method for determining the optimal operating frequency of the cold-end system of a coal-fired power unit, including the following steps:

[0011] Determine the optimization goal according to the capacity price policy of the power grid and the coal consumption - power generation - self-plant power consumption correlation characteristics of the coal-fired power generation unit;

[0012] According to the thermodynamic cycle characteristics of the coal-fired power generation unit itself, test and obtain the standard coal consumption required to maintain the maximum output of the boiler;

[0013] By changing the operating frequency of the cold-end system, change the cold working medium flow rate and power consumption of the cold-end system, and determine the optimal operating frequency of the cold-end system based on the optimization goal and the standard coal consumption.

[0014] In the second aspect, this application provides a system for determining the optimal operation of the cold-end system of a coal-fired power unit, including:

[0015] An optimization goal determination module, configured to determine the optimization goal according to the capacity price policy of the power grid and the coal consumption - power generation - self-plant power consumption correlation characteristics of the coal-fired power generation unit;

[0016] A standard coal consumption test module, configured to test and obtain the standard coal consumption required to maintain the maximum output of the boiler according to the thermodynamic cycle characteristics of the coal-fired power generation unit itself;

[0017] An optimal operating frequency determination module, configured to change the cold working medium flow rate and power consumption of the cold-end system by changing the operating frequency of the cold-end system, and determine the optimal operating frequency of the cold-end system based on the optimization goal and the standard coal consumption.

[0018] In the third aspect, this application provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the above method are implemented.

[0019] In the fourth aspect, this application provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, the steps of the above method are implemented.

[0020] In a fifth aspect, the present application provides a computer program product, which includes computer instructions. The processor of a computer device reads the computer instructions, and the processor of the computer device executes the computer instructions to implement the steps of the above method.

[0021] Compared with the prior art, the present application has the following beneficial effects:

[0022] The present application incorporates the settlement rules of the capacity tariff policy for coal-fired power enterprises, fixes the maximum output of the fixed boiler, and uses the single-variable comparison and optimization method. By changing the operating frequency of the cold-end system and taking the maximum net profit increment as the optimization goal, the optimal operating frequency of the cold-end system of the coal-fired power unit is determined. The present application changes the traditional optimization operation method that simply pursues the unit's own performance indicators such as coal consumption and net output, closely meets the demand for maximizing the profitability of coal-fired power generation units in the new power system, helps the transformation and high-quality development of coal-fired power enterprises, and has a wide application prospect. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0024] Figure 1 It is a flowchart of the method of the present application.

[0025] Figure 2 It is a schematic diagram of the principle of the system of the present application.

[0026] Figure 3 It is a schematic diagram of the iterative optimization process of Embodiment 1 of the present application.

[0027] Figure 4 It is a schematic diagram of the iterative optimization process of Embodiment 2 of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. Usually, the components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0029] Accordingly, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the claimed present application, but merely represents selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts fall within the scope of protection of the present application.

[0030] It should be noted that like reference numerals and letters denote like items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0031] In the description of the embodiments of the present application, it should be noted that if terms such as "upper", "lower", "horizontal", "inner", etc. are used to indicate the orientation or positional relationship, it is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the inventive product is usually placed during use. This is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application. In addition, terms such as "first", "second", etc. are only used for distinguishing descriptions and cannot be construed as indicating or implying relative importance.

[0032] In addition, if the term "horizontal" appears, it does not mean that the component is required to be absolutely horizontal, but it can be slightly inclined. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but it can be slightly inclined.

[0033] In the description of the embodiments of the present application, it should also be noted that unless otherwise clearly specified and limited, if terms such as "set", "installed", "connected", "coupled" are used, they should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0034] The following further describes the present application in detail with reference to the accompanying drawings:

[0035] See Figure 1 , the embodiments of the present application disclose a method for determining the optimal operating frequency of a cold end system of a coal-fired power unit, including the following steps:

[0036] S1. Determine the optimization objective according to the capacity price policy of the power grid and the coal consumption - power generation - self-plant power consumption correlation characteristics of the coal-fired power generation unit; specifically as follows:

[0037] a. For coal-fired power units applicable to an open-cycle cold-end system:

[0038] M 1 = P g × A + (P g - P c ) × e - B × b

[0039] Wherein, M 1 is the profit value of a coal-fired power unit applicable to an open-cycle cold-end system, i.e., the optimization target; P g is the power generation output at the generator outlet of the unit; A is the compensation amount per kilowatt of power generation output given by the grid capacity tariff policy; P c is the self-use power consumption of the coal-fired power generation unit; e is the settlement for grid connection; B is the standard coal consumption of the coal-fired power generation unit; b is the purchase unit price of standard coal entering the factory.

[0040] b. For coal-fired power units applicable to a closed-cycle cold-end system equipped with a cooling tower:

[0041]

[0042] Wherein, M 2 is the profit value of a coal-fired power unit applicable to a closed-cycle cold-end system equipped with a cooling tower, i.e., the optimization target; P g is the power generation output at the generator outlet of the unit; A is the compensation amount per kilowatt of power generation output given by the grid capacity tariff policy; P c is the self-use power consumption of the coal-fired power generation unit; e is the settlement for grid connection; B is the standard coal consumption of the coal-fired power generation unit; b is the purchase unit price of standard coal entering the factory; W cr is the outlet flow of the cold-end system; is the water consumption of the cooling tower; c is the make-up water unit price of the cooling tower.

[0043] S2 According to the thermodynamic cycle characteristics of the coal-fired power generation unit itself, the standard coal consumption consumed when the boiler needs to maintain the maximum output is measured; specifically as follows:

[0044] The standard coal consumption B of the boiler of the coal-fired generator b is as follows:

[0045]

[0046] Wherein, D ms is the main steam flow of the boiler, h ms is the main steam enthalpy value at the outlet of the boiler superheater, D rh is the hot reheat steam flow, h rh is the steam enthalpy value at the outlet of the boiler reheater, D rc is the cold reheat steam flow, h rc is the steam enthalpy value at the inlet of the boiler reheater, D gsis the feed water flow rate, h gs is the enthalpy value of the feed water at the boiler inlet, D zj is the desuperheating water flow rate of the boiler reheater, h zj is the enthalpy value of the desuperheating water of the boiler reheater, D gj is the desuperheating water flow rate of the superheater, h gj is the enthalpy value of the desuperheating water of the boiler superheater; η b is the boiler thermal efficiency; η p is the pipeline efficiency;

[0047] The main steam flow rate of the boiler D ms and the hot reheat steam flow rate D rh and the cold reheat steam flow rate D rc and the feed water flow rate D gs and the desuperheating water flow rate of the boiler reheater D zj and the desuperheating water flow rate of the superheater D gj follow the following relationship:

[0048] D ms = D gs + D gj

[0049] D rh = D rc + D zj

[0050] D rc = D ms - D ex1 - D ex2 - D leak

[0051] In the formula, D ex1 is the extraction steam from the first stage of the high-pressure cylinder, D ex2 is the extraction steam from the second stage of the high-pressure cylinder, D leak is the external leakage of the shaft seal;

[0052] The extraction steam from the first stage of the high-pressure cylinder D ex1 and the extraction steam from the second stage of the high-pressure cylinder D ex2 are calculated according to the heat balance and material balance of the high-pressure heaters in the regenerative system corresponding to the extraction steam from the first stage and the second stage:

[0053]

[0054]

[0055] Among them, h gj1in is the enthalpy value of the water inlet of the No. 1 high-pressure heater; h gj2in is the enthalpy value of the water inlet of the No. 2 high-pressure heater; h gj1ss is the enthalpy value of the drain water of the No. 1 high-pressure heater; h gj2ss is the enthalpy value of the drain water of the No. 2 high-pressure heater; hex1 is the enthalpy value of the extraction steam from the first stage of the high-pressure cylinder; h ex2 is the enthalpy value of the extraction steam from the second stage of the high-pressure cylinder;

[0056] The external leakage of the shaft seal D leak is given by the turbine manufacturer:

[0057] D leak = f 4 (D ms , P ms )

[0058] The boiler thermal efficiency η b is obtained from the on-site special test:

[0059] η p = f 1 (D ms )

[0060] The pipeline efficiency η p takes a fixed value of 0.99.

[0061] S3 determines the optimal operating frequency of the cold-end system by changing the operating frequency of the cold-end system, changing the cold working fluid flow rate and power consumption of the cold-end system, with the optimization goal and standard coal consumption; specifically as follows:

[0062] The standard coal consumption B of the coal-fired generator boiler b is as follows:

[0063]

[0064] where D ms is the main steam flow rate of the boiler, h ms is the enthalpy value of the main steam at the outlet of the boiler superheater, D rh is the hot reheat steam flow rate, h rh is the enthalpy value of the steam at the outlet of the boiler reheater, D rc is the cold reheat steam flow rate, h rc is the enthalpy value of the steam at the inlet of the boiler reheater, D gs is the feed water flow rate, h gs is the enthalpy value of the feed water at the inlet of the boiler, D zj is the desuperheating water flow rate of the boiler reheater, h zj is the enthalpy value of the desuperheating water of the boiler reheater, D gj is the desuperheating water flow rate of the superheater, h gj is the enthalpy value of the desuperheating water of the boiler superheater; η b is the boiler thermal efficiency; η p is the pipeline efficiency;

[0065] The main steam flow rate D of the boiler ms 、the hot reheat steam flow rate D rh 、the cold reheat steam flow rate Drc 、 Feed water flow rate D gs 、 Reheater desuperheating water flow rate D of the boiler zj And desuperheating water flow rate D of the superheater gj Follow the following relationships:

[0066] D ms = D gs + D gj

[0067] D rh = D rc + D zj

[0068] D rc = D ms - D ex1 - D ex2 - D leak

[0069] In the formula, D ex1 Is the extraction steam of the first stage of the high-pressure cylinder, D ex2 Is the extraction steam of the second stage of the high-pressure cylinder, D leak Is the external leakage of the shaft seal;

[0070] The extraction steam D of the first stage of the high-pressure cylinder ex1 And the extraction steam D of the second stage of the high-pressure cylinder ex2 Are calculated according to the heat balance and material balance of the high-pressure heaters in the regenerative system corresponding to the extraction steam of the first stage and the second stage:

[0071]

[0072]

[0073] Among them, h gj1in Is the enthalpy value of the inlet water of the No. 1 high-pressure heater; h gj2in Is the enthalpy value of the inlet water of the No. 2 high-pressure heater; h gj1ss Is the enthalpy value of the drain water of the No. 1 high-pressure heater; h gj2ss Is the enthalpy value of the drain water of the No. 2 high-pressure heater; h ex1 Is the enthalpy value of the extraction steam of the first stage of the high-pressure cylinder; h ex2 Is the enthalpy value of the extraction steam of the second stage of the high-pressure cylinder;

[0074] The external leakage of the shaft seal D leak Is given by the turbine manufacturer:

[0075] D leak = f 4 (D ms , P ms )

[0076] The boiler thermal efficiency η b Is obtained according to the on-site special test:

[0077] η p = f 1 (D ms )

[0078] Pipeline efficiency η p Take a fixed value of 0.99.

[0079] As Figure 2 shown, an embodiment of the present application discloses an optimal operation determination system for a cold end system of a coal-fired power generation unit, including:

[0080] An optimization target determination module, configured to determine an optimization target according to the capacity price policy of the power grid and the coal consumption - power generation - self-plant power consumption correlation characteristics of the coal-fired power generation unit;

[0081] A standard coal consumption measurement module, configured to measure the standard coal consumption required for the boiler to maintain the maximum output according to the thermodynamic cycle characteristics of the coal-fired power generation unit itself;

[0082] An optimal operation frequency determination module, configured to change the cold working medium flow rate and power consumption of the cold end system by changing the operation frequency of the cold end system, and determine the optimal operation frequency of the cold end system based on the optimization target and the standard coal consumption.

[0083] The present application is directed to the cold end system of a coal-fired power generation unit. The cold end system may be a circulating water pump or a direct air-cooled system. Taking the two as examples respectively, the optimal operation frequency determination method of the present application will be described below.

[0084] Embodiment 1

[0085] As Figure 3 shown, in a feasible embodiment of the present application, taking a wet-cooled coal-fired power generation unit with a variable-frequency configuration of the circulating water pump of a certain cold end system as an example, the optimal operation determination method for the circulating water pump of the coal-fired power generation unit of the present application includes the following steps:

[0086] Step 1: Determine the optimization target according to the capacity price policy of the power grid where the coal-fired power generation unit is located and the coal consumption - power generation - self-plant power consumption correlation characteristics of the coal-fired power generation unit.

[0087] For the capacity price policy of the power grid where the coal-fired power generation unit is located, according to the power generation output P g at the generator outlet approved by the power grid, a compensation of A yuan is given per kilowatt. At this time, the boiler needs to maintain the maximum output.

[0088] Among them, P g is the power generation output at the generator outlet of the unit, in kW; A is the compensation amount per kilowatt of power generation output given by the power grid capacity price policy, in yuan / kW.

[0089] Clarify the optimization target, that is, the profit value M = P g × A + (Pg -P c ) × e - B × b, applicable to coal-fired power generation units in open-cycle cold-end systems, or coal-fired power generation units in closed-cycle cold-end systems equipped with cooling towers.

[0090] Among them, M is the optimization target, yuan; P c is the plant power consumption of the coal-fired power generation unit, kWh; e is the settlement for grid connection, yuan / kWh; B is the standard coal consumption of the coal-fired power generation unit, t; b is the purchase unit price of standard coal entering the factory, yuan / t. W cr is the water flow at the outlet of the circulating water pump, t / h; is the water consumption of the cooling tower, %; c is the make-up water unit price of the cooling tower, yuan / t.

[0091] Implementation time: When the grid enterprise approves the maximum power generation output of the coal-fired power generation unit.

[0092] Step 2: According to the thermal cycle characteristics of the coal-fired power generation unit itself, through on-site testing, clarify the standard coal consumption required to maintain the maximum output of the boiler.

[0093] Test condition boundary parameters: operating back pressure p b , generator outlet electric power P g0 , boiler main steam flow D ms , feed water flow D gs , hot reheat and cold reheat steam flows D rh and D rc , boiler reheater D zj and superheater desuperheating water flow D gj . The units are kPa, kW, t / h, t / h, t / h, t / h, t / h, t / h respectively.

[0094] Determine the standard coal consumption B of the boiler coal-fired generator through the following formula b . Once the main steam flow at the boiler outlet is given, the standard coal consumption B of the boiler coal-fired generator b will remain constant.

[0095]

[0096] In the formula, h ms , h rh , h rc , h gs , h zj and h gj are the enthalpy values of the main steam at the outlet of the boiler superheater, the enthalpy values of the steam at the outlet and inlet of the boiler reheater, the enthalpy value of the feed water at the boiler inlet, and the enthalpy values of the desuperheating water of the boiler reheater and superheater, kJ / kg. They can be calculated from the on-site pressure and temperature measurement values.

[0097] η b is the boiler thermal efficiency, as shown in Equation (1), which varies for different boilers and is obtained based on on-site special tests.

[0098] η p = f 1 (D ms ) (2)

[0099] η p is the pipeline efficiency, with a fixed value of 0.99.

[0100] D ms 、D rh 、D rc 、D gs 、D zj and D gj are the main steam flow rate at the outlet of the boiler superheater, the steam flow rates at the outlet and inlet of the boiler reheater, the feed water flow rate at the boiler inlet, and the desuperheating water flow rates of the boiler reheater and superheater, in t / h. The above parameters are not independent of each other but follow a certain correlation, as shown in Equation (3).

[0101]

[0102] In the formula, D ex1 、D ex2 and D leak are the extraction steam from the first stage of the high-pressure cylinder, the extraction steam from the second stage, and the external leakage of the shaft seal, in t / h. Among them, D ex1 and D ex2 can be calculated based on the heat balance and material balance of the high-pressure heaters in the regenerative system corresponding to the extraction steam from the first stage and the extraction steam from the second stage. See Equation (4).

[0103]

[0104] h gj1in 、h gj2in 、h gj1ss 、h gj2ss 、h ex1 、h ex2 are the enthalpy values of the feed water entering the No. 1 high-pressure heater, the enthalpy values of the drain water, the enthalpy values of the feed water entering the No. 2 high-pressure heater, the enthalpy values of the drain water, the enthalpy values of the extraction steam from the first stage and the second stage of the high-pressure cylinder, with the unit of kJ / kg.

[0105] D leak is a binary function of the main steam flow rate D ms and the main steam pressure P ms , as shown in Equation (5), and is given by the turbine manufacturer.

[0106] D leak = f 4 (D ms , P ms) (5)

[0107] Step 3: By changing the operating frequency of the circulating water pump, change the circulating cooling water flow rate and the power consumption of the circulating water pump, and maximize the optimization objective proposed in this application to determine the optimal operating frequency of the circulating water pump.

[0108] Agree on the optimization boundary. The ambient air temperature is t a , in °C. During the period from the start to the end of the optimization operation, the ambient air temperature remains basically unchanged. Whether for an open-loop or closed-loop system, it is considered that the ambient air temperature has no impact on the back pressure of the unit and the power generation output.

[0109] Select the reference condition and study the full variable-frequency operation of the circulating water pumps configured in the unit. The auxiliary power consumption P of other auxiliary machines except the circulating water pumps c0 , the operating frequency f of the circulating water pump 0 Take the minimum value of the circulating water pump frequency corresponding to the circulating cooling water flowing to the cooling tower, and the corresponding power consumption P of the circulating water pump f0 , the operating back pressure P b0 , the electric power at the generator outlet P g0 . Since the main steam flow rate of the boiler remains unchanged, in a coal-fired power generation unit, except for the circulating water pump, the power consumption of other auxiliary machines remains unchanged.

[0110] For a coal-fired power generation unit with an open-loop cold-end system, calculate the profit M of the reference condition 0 :

[0111] M 0 = P g0 ×A + ((P g0 - P c0 ) × e - B × b) × t / 60

[0112] For a coal-fired power generation unit with a closed-loop cold-end system equipped with a cooling tower, calculate the profit M of the reference condition:

[0113]

[0114] Among them, t is the duration of the reference condition, in minutes. It is agreed that the duration of each optimization operation is fixed and unchanged.

[0115] Start the optimization iteration

[0116] Step 1: On the basis of the reference condition, increase the operating frequency of the circulating water pump by 1 Hz each time, f 1 = f 0 + 1;

[0117] Step 2: Make a judgment, f 0 < 507; if not, then terminate the optimization process and output the maximum profit M bsetand the optimal operating frequency f of the circulating water pump bset ; Yes, go to Step3.

[0118] Step3: Obtain the power consumption P of the corresponding circulating water pump f1 , the operating back pressure P b1 , the electric power at the generator outlet P g1 . The auxiliary power consumption P c1 = (P f1 - P f0 ) + P c0 ;

[0119] step4: Calculate the profit value M 1 = P g1 × A + ((P g1 - P c1 ) × e - B × b) × t / 60 or

[0120] Step5: Make a determination, M 1 - M 0 ≥ 07; If not, let M bset = M 0 ; If so, go to Step6.

[0121] Step6: Let M bset = M 1 , and then increase the operating frequency of the circulating water pump by 1Hz, go to step2.

[0122] The iteration ends, output the optimization result, that is: the maximum profit value M bset , and the corresponding optimal frequency f of the circulating water pump bset .

[0123] Embodiment 2

[0124] As Figure 4 shown, in another embodiment of the present application, taking a certain direct air-cooled coal-fired generating unit as an example, the method for determining the optimal operation of the direct air-cooled system of the coal-fired generating unit of the present application includes the following steps:

[0125] Step1: According to the capacity tariff policy of the power grid where the coal-fired generating unit is located, and the correlation characteristics of coal consumption - power generation - auxiliary power consumption of the coal-fired generating unit, determine the optimization goal of the present application.

[0126] The capacity tariff policy of the power grid where the coal-fired generating unit is located gives a compensation of A yuan per kilowatt according to the approved power generation output P g at the generator outlet of the power grid. At this time, the boiler needs to maintain the maximum output.

[0127] Among them, P gP is the power generation output at the generator outlet of the unit, in kW; A is the compensation amount per kilowatt of power generation output given by the grid capacity tariff policy, in yuan / kW.

[0128] Define the optimization objective of this application, that is, the profit value:

[0129] M = P g × A + (P g - P c ) × e - R × b

[0130] where M is the optimization objective, in yuan; P c is the plant power consumption of the coal-fired generating unit, in kWh; e is the settlement for grid connection, in yuan / kWh; B is the standard coal consumption of the coal-fired generating unit, in t; b is the purchase unit price of standard coal entering the plant, in yuan / t.

[0131] Implementation time: When the grid enterprise approves the maximum power generation output of the coal-fired generating unit.

[0132] Step 2: According to the thermodynamic cycle characteristics of the coal-fired generating unit itself, through on-site testing, clarify the standard coal consumption required to maintain the maximum output of the boiler.

[0133] Test condition boundary parameters: operating back pressure p b , generator outlet electric power P g0 , boiler main steam flow D ms , feed water flow D gs , hot reheat and cold reheat steam flows D rh and D rc , boiler reheater D zj and superheater desuperheating water flow D gj . The units are kPa, kW, t / h, t / h, t / h, t / h, t / h, t / h respectively.

[0134] Determine the standard coal consumption B of the boiler coal-fired generator of the boiler through the following formula b . Once the main steam flow at the boiler outlet is given, the standard coal consumption B of the boiler coal-fired generator of the boiler b will remain constant.

[0135]

[0136] In the formula, h ms , h rh , h rc , h gs , h zj and h gj are the main steam enthalpy value at the outlet of the boiler superheater, the steam enthalpy values at the outlet and inlet of the boiler reheater, the feed water enthalpy value at the inlet of the boiler, and the enthalpy values of the desuperheating water for the boiler reheater and superheater, in kJ / kg. They can be calculated from the on-site pressure and temperature measurement values.

[0137] η b is the boiler thermal efficiency, as shown in Equation (1), which varies for different boilers and is obtained based on on-site special tests.

[0138] η p = f 1 (D ms ) (2)

[0139] η p is the pipeline efficiency, with a fixed value of 0.99.

[0140] D ms 、D rh 、D rc 、D gs 、D zj and D gj are the main steam flow rate at the outlet of the boiler superheater, the steam flow rates at the outlet and inlet of the boiler reheater, the feed water flow rate at the boiler inlet, and the desuperheating water flow rates of the boiler reheater and superheater, respectively, in t / h. The above parameters are not independent of each other but follow a certain correlation, as shown in Equation (3).

[0141]

[0142] In the formula, D ex1 、D ex2 and D leak are the extraction steam of the first stage of the high-pressure cylinder, the extraction steam of the second stage, and the external leakage of the shaft seal, respectively, in t / h. Among them, D ex1 and D ex2 can be calculated based on the heat balance and material balance of the high-pressure heaters in the regenerative system corresponding to the extraction steam of the first stage and the extraction steam of the second stage. See Equation (4).

[0143]

[0144] h gj1in 、h gj2in 、h gj1ss 、h gj2ss 、h ex1 、h ex2 are the enthalpy values of the feed water entering the No. 1 high-pressure heater, the enthalpy values of the drain water, the enthalpy values of the feed water entering the No. 2 high-pressure heater, the enthalpy values of the drain water, the enthalpy values of the extraction steam of the first stage and the extraction steam of the second stage of the high-pressure cylinder, respectively, with the unit of kJ / kg.

[0145] D leak is a binary function of the main steam flow rate D ms and the main steam pressure P ms , as shown in Equation (5), and is given by the turbine manufacturer.

[0146] D leak = f 4 (D ms, P ms ) (5)

[0147] Step 3: By changing the operating frequency of the forced draft cooling fan group, change the cooling air volume and the power consumption of the forced draft cooling fan group, and maximize the optimization objective proposed in this application to determine the optimal operating frequency of the forced draft cooling fan group.

[0148] Define the optimization boundary. The ambient air temperature is t a , in °C. During the period from the start to the end of the optimization operation, the ambient air temperature remains basically unchanged. Therefore, it is agreed that the ambient air temperature has no influence on the unit back pressure and the power generation output.

[0149] Select the reference operating condition. The auxiliary power consumption P c0 excluding the forced draft cooling fan group, the operating frequency of the forced draft cooling fan group is f 0 , the corresponding power consumption of the forced draft cooling fan group is P f0 , the operating back pressure is P b0 , and the electric power at the generator outlet is P g0 . Since the main steam flow of the boiler remains unchanged, in a coal-fired power generation unit, except for the forced draft cooling fan group, the power consumption of other auxiliary equipment remains unchanged.

[0150] Calculate the profit of the reference operating condition:

[0151] M 0 = P g0 ×A + ((P g0 - P c0 ) × e - B × b) × t / 60

[0152] where t is the duration of the reference operating condition, in minutes. It is agreed that the duration of each optimization operation is fixed and unchanged.

[0153] Start the optimization iteration

[0154] Step 1: On the basis of the reference operating condition, increase the operating frequency of the forced draft cooling fan group by 1 Hz each time, fl = f0 + 1

[0155] Step 2: Make a judgment. If f 0 < 507; otherwise, terminate the optimization process and output the maximum profit M bset and the optimal fan frequency f bset ; if yes, go to Step 3.

[0156] Step 3: Obtain the corresponding power consumption of the forced draft cooling fan group P f1 , the operating back pressure P b1 , and the electric power at the generator outlet P g1 . The auxiliary power consumption P c1 = (P f1 - P f0 ) + P c0 ;

[0157] Step 4: Calculate the profit value M 1 = P g1 × A + ((P g1 - P c1 ) × e - B × b) × t / 60;

[0158] Step 5: Make a judgment. M 1 - M 0 ≥ 07; If not, let M bset = M 0 ; If so, go to Step 6.

[0159] Step 6: Let M bset = M 1 ; Then increase the operating frequency of the air-cooled fan group by 1 Hz and go to step 2.

[0160] The iteration ends, and the optimization result is output, that is: the maximum profit value M bsett , and the corresponding optimal fan frequency f bset .

[0161] The computer device provided by an embodiment of the present application. The computer device of this embodiment includes: a processor, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps in the above-mentioned method embodiments are implemented. Or, when the processor executes the computer program, the functions of each module / unit in the above-mentioned device embodiments are implemented.

[0162] The computer program can be divided into one or more modules / units. The one or more modules / units are stored in the memory and executed by the processor to complete the present application.

[0163] The computer device can be a computing device such as a desktop computer, a notebook, a palm computer, and a cloud server. The computer device may include, but is not limited to, a processor and a memory.

[0164] The processor may be a central processing unit (CPU), or may also be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.

[0165] The memory can be used to store the computer program and / or modules. By running or executing the computer program and / or modules stored in the memory, and by invoking the data stored in the memory, the processor implements various functions of the computer device.

[0166] If the modules / units integrated in the computer device are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, to implement all or part of the processes in the above-described embodiment methods of the present application, it can also be completed by instructing relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by a processor, the steps of the above various method embodiments can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in the form of source code, object code, executable file, or some intermediate form, etc. The computer-readable medium can include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disc, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal, and software distribution medium, etc. It should be noted that the content included in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium does not include electrical carrier signals and telecommunication signals.

[0167] The embodiment of the present application also provides a computer program product or a computer program. The computer program product or the computer program includes computer instructions, and the computer instructions are stored in a computer-readable storage medium. The processor of the computer device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the computer device executes Figure 1 the methods provided in the various alternative manners in

[0168] The terms "first", "second", etc. in the description, claims, and drawings of the embodiments of the present application are used to distinguish different objects, rather than to describe a specific order. In addition, the term "comprising" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, device, product, or equipment that includes a series of steps or units is not limited to the listed steps or modules, but optionally further includes steps or modules not listed, or optionally further includes other step units inherent to these processes, methods, devices, products, or equipment.

[0169] In the embodiments of the present application, the term "module" or "unit" refers to a computer program with a predetermined function or a part of a computer program, which works together with other related parts to achieve a predetermined goal, and can be fully or partially implemented by using software, hardware (such as a processing circuit or a memory), or a combination thereof. Similarly, one processor (or multiple processors or memories) can be used to implement one or more modules or units. In addition, each module or unit can be a part of an overall module or unit that includes the functions of the module or unit.

[0170] Those of ordinary skill in the art can realize that the units and algorithm steps of the examples described in combination with the embodiments disclosed herein can be implemented by electronic hardware, computer software, or a combination of the two. To clearly illustrate the interchangeability of hardware and software, the components and steps of the examples have been generally described according to their functions in this description. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present application.

[0171] The methods and related devices provided in the embodiments of the present application are described with reference to the method flowcharts and / or structural schematic diagrams provided in the embodiments of the present application. Specifically, each process and / or block of the method flowchart and / or structural schematic diagram, as well as the combination of the processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable devices to generate a machine, such that the instructions executed by the processor of the computer or other programmable devices generate a device for implementing the functions specified in Figure 1 one process or multiple processes and / or structural schematic Figure 1 one block or multiple blocks. These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable device to work in a specific manner, such that the instructions stored in the computer-readable memory generate a manufactured article including an instruction device, or are transmitted through a computer-readable storage medium. The computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center in a wired manner (such as coaxial cable, optical fiber, digital line (DSL)) or a wireless manner (such as infrared, wireless, microwave, etc.). The instruction device implements the functions in Figure 1 one process or multiple processes and / or structural schematic Figure 1The functions specified in one or more boxes. These computer program instructions can also be loaded onto a computer or other programmable device, so that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process. Thus, the instructions executed on the computer or other programmable device provide for implementing the steps in the process Figure 1 The steps of one or more processes and / or structural diagrams that indicate the functions specified in one or more boxes.

[0172] The steps in the method embodiments of the present application can be adjusted, combined, and deleted according to actual needs.

[0173] The modules in the device embodiments of the present application can be combined, divided, and deleted according to actual needs.

[0174] The foregoing disclosure is only for the preferred embodiments of the present application. Of course, the scope of the rights of the present application cannot be limited thereby. Therefore, equivalent changes made according to the claims of the present application still fall within the scope covered by the present application.

Claims

1. A method for determining the optimal operating frequency of the cold end system of a coal-fired power unit, characterized in that: The following steps are involved: Determine the optimization target based on the capacity price policy of the power grid and the correlation characteristics of coal consumption, power generation and power consumption of coal-fired power generating units; According to the thermal cycle characteristics of the coal-fired power generation unit, the test results show the standard coal consumption required for the boiler to maintain maximum output; By changing the operating frequency of the cold end system, changing the cold working fluid flow rate and the power consumption of the cold end system, the optimal operating frequency of the cold end system is determined in order to find the optimal target and standard coal consumption.

2. The method for determining the optimal operating frequency of the cold end system of a coal-fired power unit according to claim 1, characterized in that: According to the capacity price policy of the power grid and the correlation characteristics of coal consumption, power generation and power consumption of coal-fired power generation units, the optimization objectives are determined, including: M1=P g ×A+(P g -P c )×e-B×b Among them, M1 is the profit value of the coal-fired power unit applicable to the open cycle cold end system, that is, the optimization target; P g is the unit generator export power output; A is the compensation amount per kilowatt power output given by the grid capacity price policy; P c is the power consumption of the coal-fired generating unit; e is the settlement grid connection; B is the standard coal consumption of the coal-fired generating unit; and b is the purchase price of standard coal into the factory.

3. The method for determining the optimal operating frequency of the cold end system of a coal-fired power unit according to claim 1, characterized in that: According to the capacity price policy of the power grid and the correlation characteristics of coal consumption, power generation and power consumption of coal-fired power generation units, the optimization objectives are determined, including: Among them, M2 is the profit value of the coal-fired power unit with a closed-cycle cold-end system equipped with a cooling water tower, that is, the optimization target; P g is the unit generator export power output; A is the compensation amount per kilowatt power output given by the grid capacity price policy; P c is the power consumption of coal-fired power generation units; e is the settlement and access to the grid; B is the standard coal consumption of coal-fired power generation units; b is the purchase price of standard coal in the factory; W cr is the outlet flow of the cold end system; is the water consumption of the cooling tower; c is the unit price of water replenishment for the cooling tower.

4. The method for determining the optimal operating frequency of the cold end system of a coal-fired power plant according to claim 1, characterized in that: According to the thermal cycle characteristics of the coal-fired power generation unit, the standard coal consumption required for the boiler to maintain maximum output is tested, including: Standard coal consumption of coal-fired generator boilers B b as follows: Among them, D ms is the main steam flow rate of the boiler, h ms is the main steam enthalpy at the boiler superheater outlet, D rh is the hot resteam flow rate, h rh is the steam enthalpy at the boiler reheater outlet, D rc is the cold resteam flow rate, h rc is the steam enthalpy at the boiler reheater inlet, D gs is the water flow rate, h gs is the boiler inlet feed water enthalpy, D zj is the boiler reheater desuperheating water flow rate, h zj is the enthalpy of desuperheating water in the boiler reheater, D gj is the desuperheater water flow rate, h gj is the enthalpy of desuperheating water in the boiler superheater; η b is the boiler thermal efficiency; η p for pipeline efficiency; Boiler main steam flow D ms , hot resteam flow D rh , Cold resteam flow D rc , water flow rate D gs , boiler reheater desuperheating water flow D zj And superheater desuperheating water flow D gj The following relationship applies: D ms =D gs +D gj D rh =D rc +D zj D rc =D ms -D ex1 -D ex2 -D leak Where D ex1 D is the first stage of extraction steam from high pressure cylinder ex2 D is the second stage steam extraction of high pressure cylinder leak is the shaft seal leakage; High pressure cylinder 1st stage steam extraction D ex1 And high pressure cylinder 2nd stage steam extraction D ex2 The calculation results are based on the heat balance and material balance of the high-pressure heater of the heat recovery system corresponding to the 1st and 2nd stage extraction steam: Among them, h gj1in is the water inlet enthalpy of No. 1 high-pressure heater; h gj2in is the water inlet enthalpy of No. 2 high-pressure heater; h gj1ss is the hydrophobic enthalpy of No. 1 high-pressure heater; h gj2ss is the hydrophobic enthalpy of No. 2 high-pressure heater; h ex1 h is the extraction enthalpy of the high pressure cylinder 1st stage; ex2 is the enthalpy of extraction steam from the high pressure cylinder 2; Shaft seal leakage D leak Given by the turbine manufacturer: D leak =f4(D ms ,P ms ) Boiler thermal efficiency η b According to the special field test: η p =f1(D ms ) Pipeline efficiency η p Take the value as 0.

99.

5. The method for determining the optimal operating frequency of the cold end system of a coal-fired power unit according to claim 1, characterized in that: By changing the operating frequency of the cold end system, changing the cold working medium flow rate of the cold end system and the power consumption of the cold end system, the optimal target and standard coal consumption are sought to determine the optimal operating frequency of the cold end system, including: Step 3-1, agree on the optimal boundary; Step 3-2, select the base condition, the auxiliary power consumption P of other auxiliary equipment except the cold end system c0 ; The operating frequency f0 of the cold end system takes the minimum value of the cold end system frequency corresponding to the cooling water tower on the circulating cooling water, and the corresponding cold end system power consumption P f0 ; Operation back pressure P b0 , generator output power P g0 ; a. For coal-fired power units with open cycle cold end systems, calculate the profit M0 under the benchmark conditions: M0=P g0 ×A+((P g0 -P c0 )×e-B×b)×t / 60 Among them, t is the duration of the benchmark condition, and the duration of each optimization operation is fixed; b. For coal-fired power units with a closed-cycle cold-end system equipped with a cooling tower, calculate the profit M under the benchmark operating conditions: Step 3-3, iterate and optimize, output the maximum profit value and the corresponding optimal frequency of the cold end system.

6. The method for determining the optimal operating frequency of the cold end system of a coal-fired power plant according to claim 5, characterized in that: The optimization iteration is specifically as follows: Step 1: Based on the baseline operating conditions, increase the operating frequency of the cold end system by 1 Hz each time: f1=f0+1 Wherein, f1 is the operating frequency of the cold end system after the operating frequency of the cold end system is increased by 1 Hz on the basis of the reference condition; Step 2: Determine whether f0 < 50? If not, the optimization process is terminated and the maximum profit M is output. bset and the optimal operating frequency f of the cold end system bset ; If yes, execute Step3; Step 3: Calculate the corresponding cold end system power consumption P f1 , operating back pressure P b1 , generator output power P g1 , power consumption of the factory P c1 : P c1 =(P f1 -P f0 )+P c0 Step 4: Calculate the profit value; a. If the coal-fired power unit is an open cycle cold end system coal-fired power unit, the profit value M1 is as follows: M1=P g1 ×A+((P g1 -P c1 )×e-B×b)×t / 60 b. If the coal-fired power unit is a coal-fired power unit with a closed-loop cold-end system equipped with a cooling water tower, the profit value M1 is as follows: Among them, W cr1 is the outlet water flow of the cold end system corresponding to the operating frequency f1; Step 5: Determine whether M1-M0≥0? If not, set M bset =M0; If yes, execute Step6; Step 6: Let M bset =M1, then increase the cold end system operating frequency by 1 Hz, and return to step 2.

7. A system for determining the optimal operation of the cold end system of a coal-fired power unit, characterized in that: include: The optimization target determination module is used to determine the optimization target based on the capacity electricity price policy of the power grid and the correlation characteristics of coal consumption, power generation and power consumption of the coal-fired power generation unit; The standard coal consumption test module is used to test the standard coal consumption required for the boiler to maintain maximum output according to the thermal cycle characteristics of the coal-fired power generation unit itself; The optimal operating frequency determination module is used to determine the optimal operating frequency of the cold end system by changing the operating frequency of the cold end system, changing the cold working medium flow rate of the cold end system and the power consumption of the cold end system, so as to find the optimal target and standard coal consumption.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 6 are implemented.

9. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

10. A computer program product, characterized in that The computer program product includes computer instructions. A processor of a computer device reads the computer instructions, and the processor of the computer device executes the computer instructions to implement the steps of the method according to any one of claims 1 to 6.

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