A method, device and storage medium for optimizing circulating water pump of coal-fired generator set

Abstract

The present invention provides a method for optimizing a circulating water pump of a coal-fired generator set, comprising: obtaining a performance curve of circulating pump power and circulating pump flow according to performance test parameters of the circulating water pump in each operation mode and the operation frequency corresponding to each operation mode; obtaining the circulating pump power consumption and circulating pump flow of the seawater level under actual operation conditions according to the performance curve of the seawater level, the circulating pump power and the circulating pump flow; calculating the condenser heat load under actual operation conditions according to the obtained circulating water flow; calculating the overall heat transfer coefficient of the condenser under actual operation conditions according to the condenser heat load; calculating the overall heat transfer coefficient under variable circulating water flow conditions according to the overall heat transfer coefficient under actual operation conditions; calculating the condenser saturation temperature under variable circulating water flow conditions according to the overall heat transfer coefficient; calculating the condenser back pressure under variable circulating water flow conditions according to the condenser saturation temperature under variable circulating water flow conditions; obtaining the slightly increased power of the generator set under the corresponding condenser operation back pressure according to the condenser back pressure under the variable circulating water flow condition and the slightly increased power curve. The present invention provides a method for optimizing a circulating water pump for a coal-fired generator set. By obtaining the circulating pump power consumption value and the slight increase in power of the generator set at the corresponding seawater level, the difference between the slight increase in power of the generator set and the circulating pump power consumption value is the net increase in power of the generator set. This enables the generator set to achieve the maximum net increase in power under different seawater level conditions, thereby improving the power generation efficiency of the generator set.

Description

Technical Field

[0001] The present invention relates to the technical field of circulating water systems, and in particular to a method, equipment and storage medium for optimizing a circulating water pump of a coal-fired generator set. Background Art

[0002] The cold end system is an important part of the steam turbine of a coal-fired power generation unit. While acting as a cold source, it also has to ensure the vacuum of the exhaust port of the low-pressure cylinder of the steam turbine. The circulating water pump is the core equipment of the cold end system. As a power unit, it provides cooling circulating water for the cold end system. In different operating modes of the circulating water pump, the power consumption of the circulating water pump will change. At the same time, it provides cooling water of different flow rates to the cold end system, and the condenser vacuum changes with the cooling water flow rate. When the difference between the slight increase in power of the steam turbine caused by the vacuum change and the increase or decrease in power consumption of the circulating water pump reaches the maximum, that is, the operating mode of the circulating water pump when the net income power is the largest is called the optimal operating mode.

[0003] The optimized operation of the circulating water pump of the coal-fired generator set cooled by seawater circulating water will be affected by two factors. First, due to the tidal phenomenon, the water level in the forebay of the circulating water pump will change with the seawater level, causing the power of the circulating water pump to increase or decrease, and the circulating water flow rate will also change. Second, the cleanliness of the seawater in the water intake area varies in different seasons, and the corresponding degree of dirtiness of the condenser cooling pipe will also vary. Therefore, the frequency of the circulating water pump of the tidal circulating water-cooled coal-fired generator set cannot be adjusted in time, resulting in low net income power. Summary of the invention

[0004] The present invention provides a method, device and storage medium for optimizing a circulating water pump of a coal-fired generator set, which are used to solve the technical defects in the prior art that the frequency of a circulating water pump of a tidal circulating water-cooled coal-fired generator set cannot be adjusted in time and the net income power is low.

[0005] The present invention provides a method for optimizing a circulating water pump of a coal-fired generator set, comprising:

[0006] According to the parameters of the circulating water pump in each operation mode and the operation frequency corresponding to each operation mode, the performance curve of the circulating pump power is obtained;

[0007] According to the performance curve of seawater level and circulating pump power, the circulating pump power consumption value of the corresponding seawater level is obtained;

[0008] According to the parameters of the condenser, a slight increase power curve of the generator set is obtained, and according to the slight increase power curve, a slight increase power of the generator set under the corresponding condenser operating back pressure is obtained;

[0009] The difference between the slight increase in power of the generator set and the power consumption of the circulating pump is the net increase in power of the generator set.

[0010] According to the method for optimizing circulating water pumps of a coal-fired power generation unit provided by the present invention, the operating mode of the circulating water pumps is two machines and two pumps, two machines and three pumps, or two machines and four pumps.

[0011] According to the coal-fired power generation unit circulating water pump optimization method provided by the present invention, the minimum operating frequency of the circulating water pump under each operating mode is determined, and the frequency variation range of the circulating water pump is 1-2HZ.

[0012] According to the coal-fired generator set circulating water pump optimization method provided by the present invention, the circulating water pump operation mode, circulating water pump operation frequency and seawater level are obtained, and the circulating water flow rate is obtained through the performance curve of seawater level and circulating water flow rate.

[0013] According to the coal-fired generator set circulating water pump optimization method provided by the present invention, the condenser pressure is calculated by the following formula:

[0014]

[0015]

[0016]

[0017] K=K0β t β m β c ;

[0018] Q=W×c p ×(t2-t1);

[0019] p k is the condenser pressure, t1 is the cooling water inlet temperature, t2 is the cooling water outlet temperature, t s is the saturated steam temperature at the condenser pressure, K is the overall heat transfer coefficient, K0 is the basic heat transfer coefficient β t is the cooling water inlet temperature correction coefficient, β m is the correction factor for the pipe material and wall thickness, β C is the condenser cleanliness coefficient, c1 is the coefficient; v is the average flow velocity in the cooling tube, A is the condenser area, X is the logarithmic mean temperature difference, Q is the condenser heat load, W is the cooling water flow, c p is the specific heat capacity at the average temperature of cooling water.

[0020] According to the method for optimizing the circulating water pump of a coal-fired power generation unit provided by the present invention, a performance curve of seawater level and circulating water flow rate is obtained based on the parameters of the circulating water pump in each operating mode and the operating frequency corresponding to each operating mode, and corresponding seawater level data is obtained based on the performance curve of seawater level and circulating water flow rate.

[0021] According to the coal-fired generator set circulating water pump optimization method provided by the present invention, the parameters of the circulating water pump in each operating mode and the operating frequency corresponding to each operating mode are seawater level, circulating water flow rate, and circulating water pump power.

[0022] According to the method for optimizing the circulating water pump of a coal-fired power generation unit provided by the present invention, the parameters of the condenser are the actual operating back pressure and the calculated back pressure.

[0023] The present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the steps of any of the above-mentioned variable frequency circulating water pump optimization methods are implemented.

[0024] The present invention also provides a non-transitory computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the steps of any of the above-mentioned variable frequency circulating water pump optimization methods are implemented.

[0025] The method for optimizing the circulating water pump of a coal-fired generator set provided by the present invention obtains the circulating pump power consumption value of the corresponding seawater level through the performance curve of the seawater level and the circulating pump power, and obtains the slightly increased power of the generator set under the corresponding condenser operating back pressure according to the slightly increased power curve. The difference between the slightly increased power of the generator set and the circulating pump power consumption value is the net increased power of the generator set, so that the generator set can achieve the maximum net increased power under different seawater level conditions, thereby improving the power generation efficiency of the generator set. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 It is a schematic flow chart of the circulating water pump optimization method provided by the present invention;

[0028] Figure 2 Schematic diagram of the performance curve of the circulating pump power;

[0029] Figure 3 It is a schematic diagram of the performance curve of seawater level and circulating water flow rate of the circulating water pump optimization method provided by the present invention;

[0030] Figure 4 It is a schematic diagram of a slight increase power curve of a generator set of the circulating water pump optimization method provided by the present invention. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] Combine the following Figure 1-Figure 4 The present invention describes a method, device and storage medium for optimizing a circulating water pump of a coal-fired power generation unit, wherein the method for optimizing a circulating water pump of a coal-fired power generation unit comprises:

[0033] According to the parameters of the circulating water pump in each operation mode and the operation frequency corresponding to each operation mode, the performance curve of the circulating pump power is obtained;

[0034] According to the performance curve of seawater level and circulating pump power, the circulating pump power consumption value of the corresponding seawater level is obtained;

[0035] According to the parameters of the condenser, a slight increase power curve of the generator set is obtained, and according to the slight increase power curve, a slight increase power of the generator set under the corresponding condenser operating back pressure is obtained;

[0036] The difference between the slight increase in power of the generator set and the power consumption of the circulating pump is the net increase in power of the generator set.

[0037] The method for optimizing the circulating water pump of a coal-fired generator set provided by the present invention obtains the circulating pump power consumption value of the corresponding seawater level through the performance curve of the seawater level and the circulating pump power, and obtains the slightly increased power of the generator set under the corresponding condenser operating back pressure according to the slightly increased power curve. The difference between the slightly increased power of the generator set and the circulating pump power consumption value is the net increased power of the generator set, so that the generator set can achieve the maximum net increased power under different seawater level conditions, thereby improving the power generation efficiency of the generator set.

[0038] Specifically, the operating mode of the circulating water pump is two machines and two pumps, two machines and three pumps, or two machines and four pumps. The minimum operating frequency of the circulating water pump under each operating mode is determined, and the frequency variation range of the circulating water pump is 1-2HZ.

[0039] Specifically, the operation mode of the circulating water pump, the operation frequency of the circulating water pump and the seawater level are obtained, and the circulating water flow rate is obtained through the performance curve of the seawater level and the circulating water flow rate.

[0040] The condenser pressure is calculated by the following formula,

[0041]

[0042]

[0043]

[0044] K=K0β t β m β c ;

[0045] Q=W×c p ×(t2-t1);

[0046] p k is the condenser pressure, t1 is the cooling water inlet temperature, t2 is the cooling water outlet temperature, t s is the saturated steam temperature at the condenser pressure, K is the overall heat transfer coefficient, K0 is the basic heat transfer coefficient β t is the cooling water inlet temperature correction coefficient, β m is the correction factor for the pipe material and wall thickness, β C is the condenser cleanliness coefficient, c1 is the coefficient; v is the average flow velocity in the cooling tube, A is the condenser area, X is the logarithmic mean temperature difference, Q is the condenser heat load, W is the cooling water flow, c p is the specific heat capacity at the average temperature of cooling water.

[0047] According to the American Heat Transfer Institute (HEI) standard, K = K0β t β m β c ; In actual operation, under stable load conditions, only adjusting the operating mode of the circulating water pump and changing the frequency of the variable frequency circulating water pump will only change the basic heat transfer coefficient.

[0048] According to the parameters of the circulating water pump in each operation mode and the operation frequency corresponding to each operation mode, the performance curve of seawater level and circulating water flow is obtained, and the corresponding seawater level data is obtained according to the performance curve of seawater level and circulating water flow.

[0049] Specifically, the parameters of the circulating water pump in each operation mode and the operation frequency corresponding to each operation mode are seawater level, circulating water flow rate, and circulating water pump power; the parameters of the condenser are actual operating back pressure and calculated back pressure.

[0050] Example

[0051] Two 600MW ultra-supercritical coal-fired power generating units, with a condenser heat exchange area of ​​32,000m 3 The circulating water pumps include three fixed-speed circulating water pumps and one variable-frequency circulating water pump. The variable-frequency circulating water pump optimization method includes the following steps:

[0052] Determine that the seawater level change range is 7-12m and the change period is 13 hours (highest water level - lowest water level - highest water level);

[0053] Determine the minimum safe operating frequency of the circulating pump of the steam turbine. The minimum safe operating frequency of two machines and two pumps is 46Hz, and the minimum safe operating frequency of two machines and three pumps and two machines and four pumps is 41Hz. The frequency variation range within the operation cycle is 1-5Hz, and the preferred frequency variation range within the operation cycle is 1-1.5Hz. The operating frequencies under the two-machine two-pump operation mode include 50 / 49 / 48 / 47 / 46Hz, and the operating frequencies under the two-machine three-pump and two-machine four-pump operation modes include 50 / 48.5 / 47 / 45.5 / 44 / 42.5 / 41Hz.

[0054] In each operating mode of the circulating water pump and each frequency of the variable frequency circulating water pump, a circulating water system performance test of one tidal cycle is carried out, and the seawater level, circulating water flow rate, and circulating water pump power are recorded. The performance curves of the seawater level and circulating water flow rate, and the performance curves of the circulating pump power are obtained in each operating mode of the circulating water pump and the operating frequency of the variable frequency circulating water pump, such as Figure 1 , 2 shown.

[0055] During operation, the circulating water flow rate is obtained through the performance curve of seawater level and circulating water flow rate, the operating mode of the circulating water pump, the operating frequency of the variable frequency circulating water pump and the seawater level;

[0056] At a certain moment, the running data is:

[0057]

[0058]

[0059] The tidal water level is 9m, the circulating water pump consists of two machines and two pumps, the frequency of the variable frequency circulating water pump is 49Hz, and by consulting the circulating water pump characteristic chart, the circulating water flow rate is 95760t / h and the circulating water pump power is 4270kW.

[0060] The condenser heat loads of the two units are 661.96 and 665.03MW respectively.

[0061] The overall heat transfer coefficients of the two units are 2779 and 2877 W / (m2·K) respectively;

[0062] When the circulating water pump consists of two units and two pumps, and the frequency of the variable frequency circulating water pump is 41Hz, W=93600t / h, and the overall heat exchange coefficients of the two units are 2715 and 2812W / (m2·K) respectively.

[0063] The saturated steam temperatures at the unit exhaust pressure are 33.11°C and 32.86°C respectively.

[0064] The exhaust steam pressure of the two units is 5.07 and 5.05 kPa.

[0065] By checking the slight increase in power, the changes were -805 and -784kW respectively.

[0066] The circulating water pump power changes to 267kW.

[0067] If the circulating water pump consists of two machines and two pumps, and the frequency of the variable frequency circulating water pump is 41Hz, the overall power supply will drop by 1322kW.

[0068] The circulating water pump consists of two units and three pumps. The frequency of the variable frequency circulating water pump is 41Hz, W=113600t / h. The overall heat exchange coefficients of the two units are 3026 and 3134W / (m2·K) respectively.

[0069] The saturated steam temperatures at the unit exhaust pressure are 30.67 and 30.41°C respectively.

[0070] The exhaust steam pressures of the two units are 4.41 and 4.35 kPa,

[0071] By checking the power increase, the changes are 2378 and 2310kW respectively.

[0072] The circulating water pump power changes to -1657kW.

[0073] If the circulating water pump consists of two machines and three pumps, and the frequency of the variable frequency circulating water pump is 41Hz, the overall power supply will increase by 3013kW.

[0074] An electronic device may include: a processor, a communications interface, a memory, and a communications bus, wherein the processor, the communications interface, and the memory communicate with each other via the communications bus. The processor may call logic instructions in the memory to execute a variable frequency circulating water pump optimization method, the method comprising: obtaining a performance curve of the circulating pump power according to the parameters of the circulating water pump in each operating mode and the operating frequency corresponding to each operating mode;

[0075] According to the performance curve of seawater level and circulating pump power, the circulating pump power consumption value of the corresponding seawater level is obtained;

[0076] According to the parameters of the condenser, a slight increase power curve of the generator set is obtained, and according to the slight increase power curve, a slight increase power of the generator set under the corresponding condenser operating back pressure is obtained;

[0077] The difference between the slight increase in power of the generator set and the power consumption of the circulating pump is the net increase in power of the generator set.

[0078] In addition, the logic instructions in the above-mentioned memory can be implemented in the form of software functional units and can be stored in a computer-readable storage medium when sold or used as an independent product. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0079] On the one hand, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which is implemented when the computer program is executed by a processor to execute the variable frequency circulating water pump optimization method provided by the above methods, the method comprising: obtaining a performance curve of the circulating pump power according to the parameters of the circulating water pump in each operating mode and the operating frequency corresponding to each operating mode;

[0080] According to the performance curve of seawater level and circulating pump power, the circulating pump power consumption value of the corresponding seawater level is obtained;

[0081] According to the parameters of the condenser, a slight increase power curve of the generator set is obtained, and according to the slight increase power curve, a slight increase power of the generator set under the corresponding condenser operating back pressure is obtained;

[0082] The difference between the slight increase in power of the generator set and the power consumption of the circulating pump is the net increase in power of the generator set.

[0083] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0084] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0085] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for optimizing a circulating water pump of a coal-fired power generation unit, characterized in that: include: According to the parameters of the circulating water pump in each operation mode and the operation frequency corresponding to each operation mode, the performance curve of the circulating pump power is obtained; According to the performance curve of seawater level and circulating pump power, the circulating pump power consumption value of the corresponding seawater level is obtained; According to the parameters of the condenser, a slight increase power curve of the generator set is obtained, and according to the slight increase power curve, a slight increase power of the generator set under the corresponding condenser operating back pressure is obtained; The difference between the slight increase in power of the generator set and the power consumption of the circulating pump is the net increase in power of the generator set; The condenser pressure is calculated by the following formula, Q=W×c p ×(t2-t1); p k is the condenser pressure, t1 is the cooling water inlet temperature, t2 is the cooling water outlet temperature, t s is the saturated steam temperature at the condenser pressure, K is the overall heat transfer coefficient, K0 is the basic heat transfer coefficient β t is the cooling water inlet temperature correction coefficient, β m is the correction factor for the pipe material and wall thickness, β C is the condenser cleanliness coefficient, c1 is the coefficient; v is the average flow velocity in the cooling tube, A is the condenser area, X is the logarithmic mean temperature difference, Q is the condenser heat load, W is the cooling water flow, c p is the specific heat capacity at the average temperature of cooling water; According to the parameters of the circulating water pump in each operation mode and the operation frequency corresponding to each operation mode, a performance curve of seawater level and circulating water flow is obtained, and the corresponding seawater level data is obtained according to the performance curve of seawater level and circulating water flow; The parameters of the circulating water pump in each operation mode and the operation frequency corresponding to each operation mode are seawater level, circulating water flow rate, and circulating water pump power.

2. The method for optimizing the circulating water pump of a coal-fired power generation unit according to claim 1, characterized in that: The circulating water pumps are operated in a two-machine two-pump mode, a two-machine three-pump mode, or a two-machine four-pump mode.

3. The method for optimizing the circulating water pump of a coal-fired power generation unit according to claim 2, characterized in that: Determine the minimum operating frequency of the circulating water pump under each operating mode, and the frequency variation range of the circulating water pump is 1-5HZ.

4. The method for optimizing the circulating water pump of a coal-fired power generation unit according to claim 3, characterized in that: The operation mode and frequency of the circulating water pump and the seawater level are obtained, and the circulating water flow rate is obtained through the performance curve of the seawater level and the circulating water flow rate.

5. The method for optimizing circulating water pump of coal-fired power generation unit according to claim 1, characterized in that: The parameters of the condenser are actual operating back pressure and calculated back pressure.

6. 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 program, the steps of the method for optimizing the circulating water pump of a coal-fired power generation unit as described in any one of claims 1 to 5 are implemented.

7. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method for optimizing the circulating water pump of a coal-fired power generation unit as claimed in any one of claims 1 to 5 are implemented.

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