Control method and system of steam expansion power system, terminal and storage medium

Abstract

The application relates to a control method and system of a steam expansion power system, a terminal and a storage medium, which comprises the following steps: acquiring the steam pressure, the steam temperature, the mass flow of steam and the condensing temperature of an air cooler of an inlet every interval a seconds, and calculating the enthalpy difference of the steam according to an inlet steam enthalpy table and a saturated steam enthalpy table; obtaining the work required by an expansion component according to the enthalpy difference, the mass flow of steam of the inlet and the power conversion efficiency of a double screw; calculating the actual heat dissipation of the air cooler and the actual air volume of a fan; calculating the work required by the fan according to the rated power consumption of the air cooler fan, the actual air volume of the fan and the rated air volume of the fan, so as to obtain the net work benefit; determining the optimal condensing temperature, controlling the initial rotating speed of the fan according to the optimal condensing temperature; and adjusting the rotating speed of the fan according to the actual value of the net work benefit, so that the actual value of the net work benefit approaches the maximum value of the net work benefit. The application has the effect of improving the operation benefit of the system.

Description

Technical Field

[0001] This application relates to the field of energy conservation and consumption reduction, and in particular to a control method, system, terminal and storage medium for a steam expansion power system. Background Technology

[0002] A steam expansion power system is a special type of expansion power system, mainly composed of a machine body, twin screws, synchronous gears, seals, coolers, output shafts, air coolers, vacuum pumps, and drain pumps.

[0003] An expansion power system is a device that converts the thermal energy of steam into mechanical energy. Its operating principle mainly utilizes the rotation of expansion components.

[0004] When steam enters the expansion unit from the inlet, it expands, driving the twin-screw compressor to perform work. To ensure continuous work, an air cooler is necessary to condense the steam and discharge the condensate. On one hand, the steam drives the expansion unit to perform work; on the other hand, the air cooler's fan consumes power. The total power efficiency equals the difference between these two, i.e.: Net power efficiency = Expansion power - Air cooler power consumption.

[0005] In traditional steam expansion power systems, the air coolers are not optimally controlled and often operate in a rudimentary manner. If the condensing temperature is too low, although the expansion work is large, the air cooler fan consumes a lot of energy, resulting in low overall net efficiency. If the condensing temperature is too high, although the fan power consumption is lower, the expansion work is also low, resulting in low overall net efficiency. Therefore, to maximize power efficiency, an optimal balance needs to be struck between the expansion work and the fan energy consumption. Summary of the Invention

[0006] In order to maximize the overall net benefit between the expansion power system and the air cooler, this application provides a control method, system, terminal and storage medium for a steam expansion power system.

[0007] The control method, system, terminal, and storage medium for a steam expansion power system provided in this application adopt the following technical solution: In the first aspect of this application, a control method for a steam expansion power system is provided, employing the following technical solution: A control method for a steam expansion power system includes the following steps: The steam pressure, steam temperature, steam mass flow rate, and air cooler condensing temperature at the steam inlet are acquired every a seconds, where a is an integer. Calculate the enthalpy of the input steam based on the steam pressure, steam temperature, and inlet steam enthalpy table. Calculate the enthalpy of the discharged steam based on the air cooler condensing temperature and saturated steam enthalpy table; The enthalpy difference of the steam is calculated based on the enthalpy of the input steam and the enthalpy of the output steam. Based on the enthalpy difference, the mass flow rate of steam at the inlet, and the power conversion efficiency of the twin-screw compressor, the work required for the expansion component is obtained. The work required for the expansion component It is directly proportional to the enthalpy difference; The actual heat dissipation of the air cooler is calculated based on the enthalpy of the input steam and the mass flow rate of the steam at the inlet. Obtain the ambient temperature, and calculate the actual airflow of the fan based on the air cooler's condensing temperature, rated heat transfer terminal difference, rated heat dissipation of the air cooler, actual heat dissipation of the air cooler, and specific heat of the air. Calculate the work required by the fan based on its rated power consumption, actual airflow, and rated airflow. ; Based on the work required by the expansion component The work required by the fan Achieving net work efficiency from a steam expansion power system : ; Determine the optimal condensing temperature at which the system's net work efficiency is maximized, and control the initial fan speed based on the optimal condensing temperature; By comparing the actual net work efficiency with the maximum net work efficiency, and by comparing the air cooler condensing temperature with the optimal condensing temperature, the fan speed is adjusted to bring the actual net work efficiency closer to the maximum net work efficiency.

[0008] By adopting the above technical solution, the relationship between the condensing temperature of the air cooler and the work required by the expansion components is established. The work required by the fan The relationship between the air cooler condensing temperature and the system's net work efficiency is established. These relationships are converted into calculation programs and pre-stored in the computer. By collecting real-time data on the steam temperature, steam pressure, air cooler condensing temperature, and ambient temperature at the steam inlet, and performing calculations using the pre-stored computer program, the actual value of the system's net work efficiency is obtained in real time. The PID controller compares the calculated actual value of net work efficiency with the known maximum value of net work efficiency calculated in advance through simulation. At the same time, it compares the current air cooler condensing temperature with the optimal condensing temperature. Thus, the PID controller can adjust the air cooler condensing temperature by controlling the fan speed to bring it closer to the optimal condensing temperature, thereby keeping the system operating near the maximum value of net work efficiency, improving overall performance, and achieving an optimal trade-off between the work done by the expansion system and the power consumption of the fan.

[0009] In one possible implementation, the enthalpy of the input steam is calculated based on an inlet steam enthalpy table, including: The four enthalpy points in the inlet steam enthalpy table are obtained based on the steam pressure and steam temperature at the inlet: , , , This ensures that the steam pressure and temperature at the steam inlet fall between the four enthalpy points: , The steam temperature at the inlet. The steam pressure at the inlet; Based on the linear interpolation calculation method, obtain and The enthalpy value of the first intermediate variable between them, and how to obtain it. and The enthalpy value of the second intermediate variable between them; The enthalpy of the input steam is calculated using a linear interpolation method based on the enthalpy values ​​of the first and second intermediate variables.

[0010] By adopting the above technical solution, the enthalpy value of the input steam can be calculated in real time using the linear interpolation method by pre-storing the inlet steam enthalpy table in the computer program.

[0011] In one possible implementation, the work required by the screw expander... The calculation formula is: , The mass flow rate of the steam at the inlet. This is the enthalpy difference between the inlet steam enthalpy and the outlet steam enthalpy.

[0012] In one possible implementation, the ambient temperature is obtained, and the actual airflow of the fan is calculated based on the air cooler's condensing temperature, rated heat transfer terminal difference, rated heat dissipation of the air cooler, actual heat dissipation of the air cooler, and specific heat of the air, including: The thermal coefficient is calculated based on the actual heat dissipation of the air cooler and the rated heat dissipation of the air cooler. The actual heat transfer end difference of the air cooler is calculated based on the rated heat transfer end difference and the thermal coefficient. The system operating temperature difference is calculated based on the air cooler condensing temperature, ambient temperature, and the actual heat transfer end difference of the air cooler. The actual airflow of the fan is calculated based on the system operating temperature difference, the specific heat of the air, and the actual heat dissipation of the air cooler. The system operating temperature difference and the specific heat of the air are both inversely proportional to the actual airflow of the fan.

[0013] In one possible implementation, the work required by the fan is calculated based on the rated power consumption of the air cooler fan, the actual airflow of the fan, and the rated airflow of the fan. ,include: Calculate the air volume ratio based on the actual air volume of the fan and the rated air volume of the fan; The required work of the fan is calculated based on the air volume ratio and the fan's rated power consumption. The work required by the fan It is directly proportional to the cube of the air volume ratio.

[0014] In one possible implementation, the optimal condensing temperature for maximizing the system's net work efficiency is determined, and the initial fan speed is controlled based on this optimal condensing temperature, including: Given several steam saturation temperatures, and setting the steam saturation temperatures within a temperature range [ ]; The net work efficiency of the system at interval N℃ Simulation calculations were performed to obtain the net work efficiency of multiple systems. Where 1≤N≤3; By comparing the net work efficiency of multiple systems, the maximum net work efficiency of the system is determined. The optimal condensing temperature is determined by the condensing temperature of the air cooler corresponding to the maximum net work efficiency, and the initial fan speed is set based on this optimal condensing temperature.

[0015] By adopting the above technical solution, before actual operation, it is necessary to conduct multiple simulation tests to find the optimal condensing temperature at which the system's net work efficiency is maximized. During the simulation test, only the air cooler condensing temperature is changed while keeping other variables constant. The system's net work efficiency is calculated according to the above calculation steps, so that the PID controller first controls the fan speed based on the optimal condensing temperature. When other influencing factors cause changes in the values ​​of other variables, adjustments are made in real time according to the results obtained from the above calculation steps to ensure that the system always stays near the maximum net work efficiency.

[0016] In a second aspect of this application, a steam expansion power system is provided, employing the following technical solution: A steam expansion power system includes an expansion component, an air cooler, a detection assembly, and a controller. The expansion component includes a body, a twin-screw compressor, bearings, and a synchronous gear. The body is provided with a steam inlet and a steam outlet. The air cooler is connected to a drain pump and a vacuum pump. The detection assembly includes an inlet steam temperature sensor, an inlet steam pressure sensor, and an inlet steam flow sensor located near the steam inlet. It also includes an ambient temperature sensor located outside the body and a condensate temperature sensor located on the air cooler.

[0017] By adopting the above technical solution, it is convenient to detect the temperature, pressure, and mass flow rate of the steam at the inlet, as well as the ambient temperature and the condensing temperature of the air cooler. The condensing temperature of the air cooler is equivalent to the saturated steam temperature discharged from the exhaust port.

[0018] In one possible implementation, the controller is configured as follows: The acquisition module is used to acquire the steam temperature, steam pressure, and steam mass flow rate at the steam inlet; acquire the condensing temperature of the air cooler; and acquire the ambient temperature. The calculation module is used to calculate the enthalpy difference based on the steam temperature and pressure at the inlet, and the condensing temperature of the air cooler; calculate the power output of the expansion component based on the enthalpy difference, the steam mass flow rate, and the power conversion efficiency of the twin-screw compressor; calculate the actual heat dissipation of the air cooler based on the enthalpy of the input steam and the mass flow rate of the steam at the inlet; calculate the actual airflow of the fan based on the ambient temperature, the condensing temperature of the air cooler, the rated heat transfer terminal difference, the rated heat dissipation of the air cooler, the actual heat dissipation of the air cooler, and the specific heat of the air; calculate the work required by the fan based on the rated power consumption of the air cooler fan, the actual airflow of the fan, and the rated airflow of the fan; and obtain the net work efficiency of the steam expansion power system based on the work required by the expansion component and the work required by the fan.

[0019] The feedback control module is used to adjust the fan speed in real time based on the calculation results of the calculation module and the optimal condensing temperature.

[0020] In a third aspect of this application, a terminal is provided that features control of a steam expansion power system.

[0021] The aforementioned objective three of this application is achieved through the following technical solution: A terminal includes a memory and a processor, wherein the memory stores a computer program, characterized in that: the memory also stores an inlet steam enthalpy table for inlet steam enthalpy at different temperatures and pressures, and a saturated steam enthalpy table for outlet steam enthalpy at different temperatures and pressures.

[0022] In a fourth aspect of this application, a computer storage medium is provided that can store corresponding programs and has the characteristic of facilitating the control of a steam expansion power system.

[0023] A computer-readable storage medium storing a computer program that can be loaded by a processor and executed as a control method for any of the aforementioned steam expansion power systems.

[0024] In summary, this application includes at least one of the following beneficial technical effects: 1. This application establishes the relationship between the condensation temperature of the air cooler and the work required by the expansion components. The work required by the fan The relationship between the air cooler condensing temperature and the system's net work efficiency is established. This allows for real-time calculation of the system's actual net work efficiency based on real-time monitoring data from the detection components. The maximum net work efficiency obtained through multiple simulations before system operation is used to adjust the air cooler fan speed, thereby regulating the air cooler's condensing temperature to be close to the optimal condensing temperature. This keeps the system operating near the maximum net work efficiency, improving overall performance and achieving an optimal balance between the work done by the expansion system and the power consumption of the fan. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of a steam expansion power system according to this application.

[0026] Figure 2 This is a data block diagram of the internal modules of the controller.

[0027] Figure 3 This is a control flowchart of a control method for a steam expansion power system according to this application.

[0028] Figure 4 This is a schematic diagram when four enthalpy points are selected in the inlet steam enthalpy table.

[0029] Figure 5 This is a framework diagram of a terminal and storage medium according to this application.

[0030] Explanation of reference numerals in the attached drawings: 1. Body; 11. Steam inlet; 12. Steam outlet; 2. Twin screw; 3. Bearing; 4. Synchronous gear; 5. Air cooler; 51. Fan; 6. Controller; 61. Acquisition module; 62. Calculation module; 63. Feedback control module; 7. Detection components; 71. Steam inlet temperature sensor; 72. Steam inlet pressure sensor; 73. Steam inlet flow sensor; 74. Ambient temperature sensor; 75. Condensate temperature sensor; 8. Support shaft; 81. Power output shaft; 82. Synchronous shaft; 9. Drain pump; 10. Vacuum pump. Detailed Implementation

[0031] The following is in conjunction with the appendix Figure 1-4 This application will be described in further detail.

[0032] In order to maximize the overall net benefit between the expansion power system and the air cooler, this application provides a control method, system, terminal and storage medium for a steam expansion power system.

[0033] This application discloses a steam expansion power system. (Refer to...) Figure 1The steam expansion power system includes an expansion component, an air cooler 5, a detection assembly 7, and a controller 6. The expansion component includes a body 1, twin screws 2, bearings 3, and a synchronous gear 4. Two support shafts 8 are rotatably mounted inside the body 1, one being a power output shaft 81 and the other a synchronous shaft 82. The power output shaft 81 and the synchronous shaft 82 are connected by the synchronous gear 4 to ensure synchronous rotation of the two screws. A bearing sleeve and a rotor are fixed to the body 1. The bearings 3 are rotatably mounted within the bearing sleeve to support the rotation of the shafts 8, and the rotor is connected to the power output shaft 81. One screw is fixed to the power output shaft 81, and the other screw is fixed to the synchronous shaft 82. The two screws are in a non-contact fit; in this application, the gap between the surfaces of the twin screws 2 is 10~20µm. The body 1 is provided with a steam inlet 11 and a steam outlet 12, with the steam outlet 12 connected to the air cooler 5. The air cooler 5 is equipped with a fan 51, which blows air to cool the steam, removes the heat, condenses the steam, and discharges the condensate. The air cooler 5 is also connected to auxiliary machinery such as a drain pump 9 and a vacuum pump 10. The detection assembly 7 includes an inlet steam temperature sensor 71, an inlet steam pressure sensor 72, and an inlet steam flow sensor 73 located at the steam inlet 11, as well as an ambient temperature sensor 74 located outside the unit body 1 and a condensate temperature sensor 75 located on the air cooler 5.

[0034] Reference Figure 2 Controller 6 is configured as follows: The acquisition module 61 is used to acquire the steam temperature, steam pressure and steam mass flow rate of the steam inlet 11; acquire the condensing temperature of the air cooler 5; and acquire the ambient temperature. The calculation module 62 is used to calculate the enthalpy difference based on the steam temperature and pressure at the steam inlet 11 and the condensing temperature of the air cooler 5; calculate the output power of the twin-screw 2 expander based on the enthalpy difference, the steam mass flow rate, and the power conversion efficiency of the twin-screw 2; calculate the actual heat dissipation of the air cooler 5 based on the enthalpy of the input steam and the mass flow rate of the steam at the steam inlet 11; calculate the actual airflow of the fan 51 based on the ambient temperature, the condensing temperature of the air cooler 5, the rated heat transfer terminal difference, the rated heat dissipation of the air cooler 5, the actual heat dissipation of the air cooler 5, and the specific heat of the air; calculate the work required by the fan 51 based on the rated power consumption, the actual airflow of the fan 51, and the rated airflow of the fan 51; and obtain the net work efficiency of the steam expansion power system based on the work required by the twin-screw 2 expander and the work required by the fan 51.

[0035] The feedback control module 63 is used to adjust the speed of the fan 51 in real time based on the calculation results of the calculation module 62 and the optimal condensing temperature.

[0036] Reference Figure 3 and Figure 4This application discloses a control method for a steam expansion power system, comprising the following steps: Firstly, the work required by the twin-screw expansion device is estimated, and the specific method is as follows: S101: Obtain the steam pressure, steam temperature, steam mass flow rate, and condensing temperature of the air cooler 5 at the primary steam inlet 11. An inlet steam temperature sensor 71, an inlet steam pressure sensor 72, and an inlet steam flow meter 73 are installed at the steam inlet 11 to monitor the steam temperature, steam pressure, and steam mass flow rate in real time. A condensing temperature sensor 75 is installed on the air cooler 5 to monitor its condensing temperature in real time. After the steam expands and performs work, it is in a saturated state, and its temperature and pressure correspond one-to-one. The condensing temperature of the air cooler 5 is equivalent to the saturated steam temperature at the exhaust port 12.

[0037] S102: Calculate the enthalpy of the input steam based on the steam pressure, steam temperature, and inlet steam enthalpy table at steam inlet 11.

[0038] S1021: Pre-store the known enthalpy values ​​versus temperature and pressure data curves in the computer to form an inlet steam enthalpy table. The method is as follows: Define a two-dimensional array Ex

[200]

[200] in the computer memory to store the enthalpy values ​​of feature points at different temperatures and pressures. C language example: Ex

[200]

[200] ={{0,......,2879.82}, / *Enthalpy values ​​at a pressure of 5kPa and a temperature of 1~200℃* / {0,... ,2879.59}, / *Enthalpy values ​​at a pressure of 10 kPa and a temperature range of 1~200℃* / ...... {0.98,... ,2828.27} / *Enthalpy values ​​at a pressure of 1000 kPa and a temperature of 1~200℃ * / S1022: Based on the steam pressure and temperature at inlet 11, find four enthalpy points in the inlet steam enthalpy table, ensuring that the steam pressure and temperature at inlet 11 fall between these four enthalpy points. In one implementation scenario, suppose the measured steam temperature at inlet 11 is *v* and the steam pressure at inlet 11 is *p*. Find four enthalpy points in the inlet steam enthalpy table: , , , , making .

[0039] S1023: Obtain the results according to the linear interpolation calculation method. and Obtaining the enthalpy value of the first intermediate variable and The enthalpy value of the second intermediate variable between them.

[0040] The formula for calculating the enthalpy of the first intermediate variable is: .

[0041] The formula for calculating the enthalpy of the second intermediate variable is: .

[0042] S1024: Calculate the enthalpy of the input steam using a linear interpolation method based on the enthalpy values ​​of the first and second intermediate variables.

[0043] The formula for calculating the enthalpy of input steam is: Where E is the enthalpy of the input steam. The enthalpy value of the first intermediate variable. This is the enthalpy value of the second intermediate variable.

[0044] S103: Calculate the enthalpy of the discharged steam based on the condensing temperature of air cooler 5 and the enthalpy of saturated steam table.

[0045] S1031: Create a table of saturated vapor enthalpy values ​​in computer memory. A C language example is as follows: Es

[100] ={4.28,.....,2675.77}; / * Stores the enthalpy of saturated steam from 1 to 100℃ * / S1042: Based on the saturated steam temperature, find two enthalpy points in the saturated steam enthalpy table so that the saturated steam temperature at the exhaust port falls between the two enthalpy points.

[0046] The formula for calculating the enthalpy of discharged steam is: , The enthalpy of the discharged steam, The saturated steam temperature , The table of saturated steam enthalpy and saturated steam temperature Two adjacent temperature values, The temperature in the saturated vapor enthalpy table is... enthalpy value at time The temperature in the saturated vapor enthalpy table is The enthalpy value at that time.

[0047] S104: Calculate the enthalpy difference of steam based on the enthalpy of the input steam and the enthalpy of the discharged steam.

[0048] The formula for calculating enthalpy difference is: , This is the enthalpy difference between the inlet steam enthalpy and the outlet steam enthalpy.

[0049] S105: Based on the enthalpy difference, the mass flow rate of steam at inlet 11, and the power conversion efficiency of the twin-screw compressor 2. The work required for the expansion component is calculated. The work required for the expansion component Proportional to the enthalpy difference. The work required for the expansion component. The calculation formula is: , This is the mass flow rate of steam at the inlet.

[0050] On the other hand, the work required for the fan of air cooler 5 The estimation method is as follows: S106: Calculate the actual heat dissipation of air cooler 5 per hour based on the enthalpy of the input steam and the mass flow rate of the steam at the inlet. The formula for calculating the actual heat dissipation of air cooler 5 is: , This represents the actual heat dissipation of air cooler 5 per hour. This is the mass flow rate of the steam at the inlet.

[0051] S107: Obtain the ambient temperature and calculate the actual airflow of fan 51 based on the rated heat transfer terminal difference, the rated heat dissipation of air cooler 5, the actual heat dissipation of air cooler 5, and the specific heat of air. An ambient temperature sensor 74 is installed on the outside of the unit 1 to monitor the ambient temperature in real time.

[0052] S1071: Calculate the thermal coefficient based on the actual heat dissipation of the air cooler and the rated heat dissipation of air cooler 5. The formula for calculating the thermal coefficient is: , This is the rated heat dissipation capacity of air cooler 5.

[0053] S1072: Calculate the actual heat transfer difference of the air cooler based on the rated heat transfer end difference and thermal coefficient. The formula for calculating the actual heat transfer end difference of the air cooler is: , This is the rated heat transfer terminal difference.

[0054] S1073: Calculate the system operating temperature difference based on the condensing temperature of air cooler 5, ambient temperature, and the actual heat transfer junction temperature of air cooler 5. The formula for calculating the system operating temperature difference is: , The ambient temperature.

[0055] The actual airflow of fan 51 is calculated based on the system operating temperature difference, air specific heat, and the actual heat dissipation of air cooler 5. The system operating temperature difference and air specific heat are both inversely proportional to the actual airflow of fan 51. The formula for calculating the actual airflow of fan 51 is: , This represents the actual airflow of the fan.

[0056] S108: Calculate the work required by fan 51 based on its rated power consumption, actual airflow, and rated airflow. .

[0057] S1081: Calculate the airflow ratio based on the actual airflow of fan 51 and the rated airflow of fan 51. Airflow ratio = , This refers to the actual airflow of the fan. This refers to the fan's rated airflow.

[0058] S1082: Calculate the work required by fan 51 based on the air volume ratio and the rated power consumption of fan 51. The work required by fan 51 It is directly proportional to the cube of the air volume ratio. , This is the fan's rated power consumption.

[0059] S109: Based on the work required by the expansion component The work required by fan 51 Achieving net work efficiency from a steam expansion power system : .

[0060] S1010: Determine the optimal condensing temperature at which the system's net work efficiency is maximized, and control the initial speed of fan 51 based on this optimal condensing temperature. In actual operation, to pre-determine the optimal condensing temperature, it is necessary to find the maximum value of the overall net work efficiency, thereby determining the optimal condensing temperature at which the system's net work efficiency is maximized, and controlling the initial speed of fan 51 based on this optimal condensing temperature. Specifically, this includes the following steps: Given several steam saturation temperatures, and setting the steam saturation temperatures within a temperature range [ ]; The net work efficiency of the system at interval N℃ A simulation calculation is performed, simulating steps S101 to S109 above, to obtain the net work efficiency of multiple systems. The computer then generates a test calculation data table, where 1 ≤ N ≤ 3. This application uses N = 1, i.e., calculating once every 1°C, as an example for illustration.

[0061] By comparing the net work efficiency of multiple systems, the maximum net work efficiency of the system is determined. The optimal condensing temperature is determined by the condensing temperature of the air cooler 5 corresponding to the maximum net work efficiency. A feedback signal is sent to the PID controller based on the optimal condensing temperature. The PID controller controls the initial speed of the fan 51 to stabilize the condensing temperature of the air cooler 5 at the optimal condensing temperature.

[0062] In a specific implementation scenario, a certain type of steam expansion power system and control system reads the inlet steam temperature at a certain moment through the steam pressure gauge, steam thermometer, and steam flow meter at the steam inlet. =175.68℃, absolute pressure =543.21 kPa. Based on the temperature and pressure of the inlet steam, the inlet steam enthalpy table in memory is consulted, and the following is found: ℃ ℃ kPa, kPa , , Input the enthalpy of the steam: At this point, the ambient temperature was measured using ambient temperature sensor 74. =35℃.

[0063] The efficiency of the expansion component was known to be approximately 70% before it left the factory.

[0064] The parameters of the air cooler 5 and the corresponding fan 51 are: rated heat transfer terminal difference =8℃, rated heat dissipation of air cooler 5 =22,400,000 kJ / h, specific heat of air is 1000 kJ / (kg℃), rated power consumption of fan 51 =180kW, rated airflow of fan 51 =2500m 3 / h.

[0065] Starting from a condensation temperature of 50°C, calculations were performed every 1°C to determine the system's net work efficiency, up to 70°C (the temperature range is [50°~70°]), for a total of 21 calculations. The resulting computer trial calculation data table is as follows: 50.00 2799.67 2591.31 208.36 263.38 2141.20 113.09 150.29 51.00 2799.67 2593.08 206.59 261.14 1915.81 81.00 180.13 52.00 2799.67 2594.84 204.83 258.91 1733.35 59.99 198.92 53.00 2799.67 2596.60 203.07 256.69 1582.62 45.67 211.02 54.00 2799.67 2598.35 201.32 254.48 1456.01 35.56 218.92 55.00 2799.67 2600.11 199.56 252.25 1348.16 28.23 224.03 56.00 2799.67 2601.86 197.81 250.04 1255.18 22.78 227.26 57.00 2799.67 2603.61 196.06 247.83 1174.20 18.65 229.18 58.00 2799.67 2605.36 194.31 245.62 1103.04 15.46 230.16 59.00 2799.67 2607.10 192.57 243.42 1040.01 12.96 230.46 60.00 2799.67 2608.85 190.82 241.20 983.79 10.97 230.24 61.00 2799.67 2610.58 189.09 239.02 933.34 9.37 229.65 62.00 2799.67 2612.32 187.35 236.82 887.81 8.06 228.76 63.00 2799.67 2614.05 185.62 234.63 846.52 6.99 227.64 64.00 2799.67 2615.78 183.89 232.45 808.89 6.10 226.35 65.00 2799.67 2617.51 182.16 230.26 774.47 5.35 224.91 66.00 2799.67 2619.23 180.44 228.08 742.86 4.72 223.36 67.00 2799.67 2620.96 178.71 225.90 713.73 4.19 221.71 68.00 2799.67 2622.67 177.00 223.74 686.80 3.73 220.00 69.00 2799.67 2624.39 175.28 221.56 661.82 3.34 218.22 70.00 2799.67 2626.10 173.57 219.40 638.60 3.00 216.40 By comparing the calculated data one by one, it was determined that the net output power reaches its maximum value and the net work efficiency of the system is maximized when the condensing temperature is set at 59℃.

[0066] Therefore, the controller 6 sets the given temperature of the air cooler 5 to 59°C and uses the PID controller 6 to control the speed of the fan 51, so that the condensing temperature of the air cooler 5 is controlled at around 59°C and the system operates within the maximum efficiency range.

[0067] S1011: Compare the actual net work efficiency with the maximum net work efficiency, compare the condensing temperature of air cooler 5 with the optimal condensing temperature, and adjust the fan speed 51 to make the actual net work efficiency closer to the maximum net work efficiency.

[0068] Since the system's net work efficiency is affected by various factors, such as ambient temperature, input steam temperature, and input steam pressure, the controller 6 acquires the steam pressure, steam temperature, and mass flow rate at the steam inlet 11 at intervals of 'a' seconds, acquires the condensing temperature of the air cooler 5, and acquires the ambient temperature. Here, 'a' ranges from 60 to 180 degrees Celsius and is an integer. The computer program calculates the system's actual net work efficiency in real time based on these acquired parameter values. The PID controller compares the actual net work efficiency with the maximum net work efficiency and compares the condensing temperature of the air cooler 5 with the optimal condensing temperature. The PID controller controls the condensing temperature of the air cooler 5 by controlling the fan speed, thereby maximizing the system's net work efficiency and achieving greater energy savings under the aforementioned parameter values. This application uses an 'a' of 100 seconds as an example for illustration.

[0069] Figure 5 A schematic diagram of a terminal suitable for implementing embodiments of this application is shown.

[0070] like Figure 5 As shown, the terminal includes a Central Processing Unit (CPU) 301, which can perform various appropriate actions and processes based on programs stored in Read-Only Memory (ROM) 302 or programs loaded from storage into Random Access Memory (RAM) 303. The RAM 303 also stores various programs and data required for system operation. The CPU 301, ROM 302, and RAM 303 are interconnected via a bus 304. An Input / Output (I / O) interface 305 is also connected to the bus 304.

[0071] The following components are connected to I / O interface 305: an input section 306 including a keyboard, mouse, etc.; an output section 307 including a cathode ray tube (CRT), liquid crystal display (LCD), and speakers, etc.; a storage section 308 including a hard disk, etc.; and a communication section 309 including a network interface card such as a LAN card and a modem, etc. The communication section 309 performs communication processing via a network such as the Internet. A drive 310 is also connected to I / O interface 305 as needed. A removable medium 311, such as a disk, optical disk, magneto-optical disk, semiconductor memory, etc., is installed on drive 310 as needed so that computer programs read from it can be installed into storage section 308 as needed.

[0072] Specifically, according to embodiments of this application, the above reference flow Figure 1 The described process can be implemented as a computer software program. For example, embodiments of this application include a computer program product comprising a computer program carried on a machine-readable medium, the computer program containing program code for performing the methods shown in the flowchart. In such embodiments, the computer program can be downloaded and installed from a network via communication section 309, and / or installed from removable medium 311. When the computer program is executed by central processing unit (CPU) 301, it performs the functions defined in the system of this application.

[0073] It should be noted that the computer-readable medium shown in this application can be a computer-readable signal medium or a computer-readable storage medium, or any combination of the two. A computer-readable storage medium can be, for example,—but not limited to—an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of a computer-readable storage medium may include, but are not limited to: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disc read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In this application, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device. In this application, a computer-readable signal medium can include a data signal propagated in baseband or as part of a carrier wave, carrying computer-readable program code. The transmitted data signal can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. The computer-readable signal medium can also be any computer-readable medium other than a computer-readable storage medium, which can send, propagate, or transmit a program for use by or in connection with an instruction execution system, apparatus, or device. The program code contained on the computer-readable medium can be transmitted using any suitable medium, including but not limited to: wireless, wire, optical fiber, register file (RF), etc., or any suitable combination thereof.

[0074] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0075] The units or modules described in the embodiments of this application can be implemented in software or hardware. The described units or modules can also be located in a processor.

[0076] In another aspect, this application also provides a computer-readable storage medium, which may be included in the terminal described in the above embodiments; or it may exist independently and not assembled into the terminal. The aforementioned computer-readable storage medium stores one or more programs that, when used by one or more processors, execute the control method for the steam expansion power system described in this application.

[0077] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of disclosure in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the foregoing disclosed concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A control method for a steam expansion power system, characterized in that: Includes the following steps: The steam pressure, steam temperature, steam mass flow rate, and condensation temperature of the air cooler (5) at the steam inlet (11) are obtained every a seconds, where a is an integer; The enthalpy of the input steam is calculated based on the steam pressure, steam temperature, and inlet steam enthalpy table at the steam inlet (11). Calculate the enthalpy of the discharged steam based on the condensation temperature and saturated steam enthalpy table of the air cooler (5); The enthalpy difference of the steam is calculated based on the enthalpy of the input steam and the enthalpy of the output steam. Based on the enthalpy difference, the mass flow rate of steam at the inlet (11), and the power conversion efficiency of the twin-screw extruder (2), the work required for the expansion component is obtained. The work required for the expansion component It is directly proportional to the enthalpy difference; The actual heat dissipation of the air cooler (5) is calculated based on the enthalpy of the input steam and the mass flow rate of the steam at the inlet. Obtain the ambient temperature, and calculate the actual air volume of the fan (51) based on the condensing temperature of the air cooler (5), the rated heat transfer end difference, the rated heat dissipation of the air cooler (5), the actual heat dissipation of the air cooler (5), and the specific heat of the air. Calculate the work required by the fan (51) based on the rated power consumption of the fan (51), the actual air volume of the fan (51), and the rated air volume of the fan (51). ; Based on the work required by the expansion component The work required by the fan (51) To obtain the net work efficiency of the steam expansion power system : ; Determine the optimal condensing temperature at which the system's net work efficiency is maximized, and control the initial fan speed based on the optimal condensing temperature; By comparing the actual net work efficiency with the maximum net work efficiency, and by comparing the air cooler condensing temperature with the optimal condensing temperature, the fan speed is adjusted to bring the actual net work efficiency closer to the maximum net work efficiency.

2. The control method for the steam expansion power system according to claim 1, characterized in that: Calculate the enthalpy of the input steam based on the inlet steam enthalpy table, including: Based on the steam pressure and steam temperature at the steam inlet (11), obtain the four enthalpy points in the inlet steam enthalpy table: , , , This ensures that the steam pressure and steam temperature at the steam inlet (11) fall between the four enthalpy points: , The steam temperature at the steam inlet (11) is... The steam pressure at the steam inlet (11); Based on the linear interpolation calculation method, obtain and The enthalpy value of the first intermediate variable between them, and how to obtain it. and The enthalpy value of the second intermediate variable between them; The enthalpy of the input steam is calculated using a linear interpolation method based on the enthalpy values ​​of the first and second intermediate variables.

3. The control method for the steam expansion power system according to claim 1, characterized in that: Work required for screw expander The calculation formula is: , The mass flow rate of steam at the inlet (11) is... This is the enthalpy difference between the inlet steam enthalpy and the outlet steam enthalpy.

4. The control method for the steam expansion power system according to claim 1, characterized in that: Obtain the ambient temperature, and calculate the actual airflow of the fan (51) based on the condensing temperature of the air cooler (5), the rated heat transfer terminal difference, the rated heat dissipation of the air cooler (5), the actual heat dissipation of the air cooler (5), and the specific heat of the air, including: The thermal coefficient is calculated based on the actual heat dissipation of the air cooler (5) and the rated heat dissipation of the air cooler (5); The actual heat transfer end difference of the air cooler is calculated based on the rated heat transfer end difference and the thermal coefficient. The system operating temperature difference is calculated based on the condensing temperature of the air cooler (5), the ambient temperature, and the actual heat transfer end difference of the air cooler (5). The actual air volume of the fan (51) is calculated based on the system operating temperature difference, the specific heat of the air and the actual heat dissipation of the air cooler (5). The system operating temperature difference and the specific heat of the air are both inversely proportional to the actual air volume of the fan (51).

5. The control method for the steam expansion power system according to claim 1, characterized in that: Calculate the work required by the fan (51) based on the rated power consumption of the fan (51), the actual air volume of the fan (51), and the rated air volume of the fan (51). ,include: The air volume ratio is calculated based on the actual air volume of the fan (51) and the rated air volume of the fan (51); The required work of the fan is calculated based on the air volume ratio and the rated power consumption of the fan (51). The work required by the fan (51) It is directly proportional to the cube of the air volume ratio.

6. The control method for the steam expansion power system according to claim 1, characterized in that: Determine the optimal condensing temperature for maximizing the system's net work efficiency, and control the initial fan speed based on this optimal condensing temperature, including: Given several steam saturation temperatures, and setting the steam saturation temperatures within a temperature range [ ]; The net work efficiency of the system at interval N℃ Simulation calculations were performed to obtain the net work efficiency of multiple systems. Where 1≤N≤3; By comparing the net work efficiency of multiple systems, the maximum net work efficiency of the system is determined. The optimal condensing temperature is determined by the condensing temperature of the air cooler corresponding to the maximum net work efficiency, and the initial fan speed is set based on this optimal condensing temperature.

7. A steam expansion power system, characterized in that: The device includes an expansion component, an air cooler (5), a detection component (7), and a controller (6). The expansion component includes a body (1), a twin screw (2), a bearing (3), and a synchronous gear (4). The body (1) is provided with an inlet (11) and an outlet (12). The air cooler (5) is connected to a drain pump (9) and a vacuum pump (10). The detection component (7) includes an inlet steam temperature detector (71), an inlet steam pressure detector (72), and an inlet steam flow detector (73) located near the inlet steam inlet (11). It also includes an ambient temperature detector (74) located outside the body (1) and a condensate temperature detector (75) located on the air cooler (5).

8. The steam expansion power system according to claim 7, characterized in that: The controller (6) is configured as follows: The acquisition module (61) is used to acquire the steam temperature, steam pressure and steam mass flow rate of the steam inlet (11); acquire the condensing temperature of the air cooler (5); and acquire the ambient temperature. The calculation module (62) is used to calculate the enthalpy difference based on the steam temperature and steam pressure at the steam inlet (11) and the condensing temperature of the air cooler (5); to calculate the power output of the expansion component based on the enthalpy difference, the mass flow rate of the steam and the power conversion efficiency of the twin screw (2); to calculate the actual heat dissipation of the air cooler (5) based on the enthalpy value of the input steam and the mass flow rate of the steam at the steam inlet (11); to calculate the actual air volume of the fan (51) based on the ambient temperature, the condensing temperature of the air cooler (5), the rated heat transfer terminal difference, the rated heat dissipation of the air cooler (5), the actual heat dissipation of the air cooler (5) and the specific heat of the air; to calculate the work required by the fan (51) based on the rated power consumption of the fan (51) of the air cooler (5), the actual air volume of the fan (51) and the rated air volume of the fan (51); and to obtain the net work efficiency of the steam expansion power system based on the work required by the expansion component and the work required by the fan (51). The feedback control module (63) is used to adjust the speed of the fan (51) in real time according to the calculation results of the calculation module (62) and the optimal condensing temperature.

9. A terminal, comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: The memory also stores an inlet steam enthalpy table of the steam enthalpy value of the steam inlet (11) at different temperatures and pressures, and a saturated steam enthalpy table of the steam enthalpy value of the steam outlet (12) at different temperatures and pressures. When the processor executes the program, it implements the method according to any one of claims 1 to 6.

10. A storage medium having a computer program stored thereon, characterized in that: When the program is executed by the processor, it implements the method as described in any one of claims 1 to 6.

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