Desulfurization wastewater zero discharge system and method for intelligent coal-fired power generation unit

Abstract

The invention discloses a desulfurization wastewater zero discharge system and method for an intelligent coal-fired power generation unit. The desulfurization wastewater zero discharge system comprises a unit flue gas system, a sedimentation tank, a desulfurization wastewater transportation system, a DCS system, a data processing system and an intelligent control system, the desulfurization wastewater transportation system comprises a desulfurization wastewater centrifugal pump, a total flow valve and branch flow valves; an outlet of the total flow valve is connected with spray guns arranged on the side wall of the boiler; the DCS system is used for collecting operation data of the coal-fired power generation unit in real time, the data processing system is used for analyzing and processing the operation data collected by the DCS system and extracting effective operation data in real time, and the intelligent control system calculates the total spraying amount of desulfurization waste water and the spraying amount, the spraying angle and the spraying speed of each spraying gun in real time according to the effective operation data. Therefore, the desulfurization waste water centrifugal pump, the total flow valve, the branch flow valves and the spray guns are controlled in real time. According to the invention, chemical agents for treating the desulfurization wastewater are saved, the investment is low, the modification amount is small, and the injected desulfurization wastewater is harmlessly treated.

Description

Technical Field

[0001] The present invention relates to the field of industrial wastewater treatment, and in particular to a treatment process for desulfurization wastewater of a thermal power unit based on numerical simulation technology, and more specifically to an intelligent coal-fired power unit desulfurization wastewater zero-discharge system and method. Background Art

[0002] Limestone-gypsum wet desulfurization technology is the most commonly used desulfurization technology in coal-fired power plants at home and abroad, so it is inevitable to produce desulfurization wastewater. For desulfurization wastewater, most domestic coal-fired power plants basically use the three-unit box process for priority treatment. The three-unit box process has the disadvantages of more equipment, larger investment, high operating cost and large equipment maintenance. These disadvantages have led to many power plants installing the above-mentioned desulfurization wastewater treatment equipment, but in actual operation, there are high operation and maintenance costs, high failure rates and low commissioning rates. Some coal-fired power plants use flue gas evaporation technology, and a large amount of desulfurization wastewater evaporates in the flue, which also faces a series of hidden dangers such as easy accumulation of dust in the flue and corrosion of the electrode plates of the dust collector caused by the flue gas temperature being lower than the acid dew point. Summary of the invention

[0003] In order to solve the problems existing in the above-mentioned desulfurization wastewater treatment process, the present invention proposes an intelligent coal-fired power generation unit desulfurization wastewater zero emission system and method, which is mainly used for the treatment of desulfurization wastewater and other sewage, saving the chemical agents used in conventional desulfurization wastewater treatment methods. Compared with conventional flue gas waste heat treatment of desulfurization wastewater, it has the characteristics of low investment and small amount of modification. At the same time, it can harmlessly treat the injected desulfurization wastewater, providing an effective way for sewage treatment.

[0004] The purpose of the present invention can be achieved through the following technical solutions.

[0005] The intelligent coal-fired power generation unit desulfurization wastewater zero-discharge system of the present invention comprises a unit flue gas system, a sedimentation tank, a desulfurization wastewater transportation system, a DCS system, a data processing system, and an intelligent control system;

[0006] The unit flue gas system includes a boiler, a dust collector, an induced draft fan, a desulfurization tower, and a chimney in a coal-fired power generation unit connected in sequence through a flue, and the lower discharge port of the desulfurization tower is connected to a sedimentation tank through a conveying pipeline;

[0007] The desulfurization wastewater transportation system includes a desulfurization wastewater centrifugal pump, a total flow valve, and a branch flow valve. The inlet of the centrifugal pump is connected to the liquid outlet of the sedimentation tank through a delivery pipeline, the outlet of the centrifugal pump is connected to the inlet of the total flow valve through a delivery pipeline, and the outlet of the total flow valve is connected to each spray gun arranged on the side wall of the boiler through a branch pipeline, and each branch pipeline is provided with a branch flow valve;

[0008] The DCS system is used to collect the operating data of the coal-fired power generation unit in real time, and the data processing system is used to analyze and process the operating data collected by the DCS system, and extract effective operating data in real time and transmit it to the intelligent control system. The intelligent control system calculates the total injection amount of desulfurization wastewater and the injection amount, injection angle, and injection speed of each spray gun in real time based on the effective operating data transmitted by the data processing system, and controls the desulfurization wastewater centrifugal pump, the total flow valve, the branch flow valve, and each spray gun in real time based on these calculated data.

[0009] Furthermore, the sedimentation tank is used to filter the substances that are hardly soluble in water in the desulfurization wastewater generated by the desulfurization tower.

[0010] Furthermore, the spray guns are located between the burnout wind and the flame folding angle of the front wall of the boiler, and are arranged in 2 to 3 layers, with 2 to 4 spray guns on each layer, and the number of spray guns on each layer is the same or different.

[0011] Furthermore, the spray angle of the spray gun nozzle can be automatically adjusted. According to the temperature field distribution state in the boiler furnace, the spray angle can be adjusted to the position of the higher temperature zone to achieve balanced temperature distribution. The adjustable range is 45° to 135° with the vertical water-cooled wall of the front wall.

[0012] Furthermore, the nozzle of the spray gun is an atomizing nozzle, which adopts a multi-hole arrangement. The nozzle area can be automatically adjusted. The number of nozzle holes is adjusted according to the temperature distribution in the boiler furnace to achieve regulation of the nozzle injection speed.

[0013] Furthermore, the DCS system collects operating data of the coal-fired power generation unit in real time, including the operating load of the boiler, operating coal quality, total coal quantity, primary and secondary air volume, primary and secondary air temperature, economizer outlet oxygen content, furnace flue gas temperature, furnace flue gas negative pressure, steam temperature at the outlet of each heating surface, steam flow rate at the outlet of each heating surface, steam pressure at the outlet of each heating surface, cooling water flow rate, and damper opening.

[0014] Furthermore, the data processing system reads the real-time operation data of the boiler from the DCS system through Modbus communication, analyzes, judges and processes the operation data collected by the DCS system, eliminates erroneous data, corrects deviation data, and obtains effective operation data.

[0015] Furthermore, the intelligent control system acquires data from the data processing system in real time, calculates in real time to form real-time velocity field and temperature field inside the boiler furnace under current operating conditions, and based on the velocity field, temperature field and effective operating data acquired in real time, with the goal of uniform furnace temperature distribution and velocity distribution, calculates in real time the total injection amount of desulfurized wastewater that meets the furnace operation requirements and the injection amount, injection angle, and injection speed of each spray gun, and feeds back the calculation results in real time to the desulfurized wastewater centrifugal pump, the total flow valve, and each branch flow valve for flow control, as well as the control of the injection angle and injection speed of each spray gun, so as to realize the spraying of desulfurized wastewater from the desulfurization tower in the coal-fired power generation unit into the boiler furnace.

[0016] Furthermore, the real-time velocity field and temperature field inside the boiler furnace in the intelligent control system are real-time calculation models of the velocity field and temperature field inside the boiler furnace based on numerical simulation technology and neural network technology, and the establishment process is as follows:

[0017] ① Use 3D CFD software to carry out 1:1 modeling according to the specific structural dimensions of the boiler on site, and use the meshing tool to mesh the established geometric model; use the effective operating data of different working conditions of the real-time data processing system to set the calculation boundary conditions, and obtain the heat flux density, temperature field and velocity field of each heating surface of the boiler through cold and hot state calculations.

[0018] ② Use one-dimensional thermal fluid software to build a boiler steam-water system model at a ratio of 1:1 based on the specific structural dimensions of the on-site steam-water system, and calculate the temperature distribution of the medium on each heating surface of the boiler based on the heat flux density of each heating surface calculated by three-dimensional CFD software;

[0019] ③ Import the temperature distribution data of each heating surface medium calculated by the one-dimensional thermal fluid software into the three-dimensional CFD software to optimize the heat flux density, temperature field and velocity field of each heating surface, and iterate the coupling calculation to achieve the coupling of the flue gas side and the steam-water side, and finally calculate and obtain the velocity field and temperature field inside the boiler furnace under typical working conditions;

[0020] ④ Using the real-time effective operation data on site, check and calibrate the calculation results of the velocity field and temperature field inside the boiler furnace under typical working conditions obtained in step ③;

[0021] ⑤ Combined with the deep neural network, the calculation results and boundary conditions of the velocity field and temperature field inside the boiler furnace after the verification and calibration in step ④ are trained under full working conditions to realize the real-time calculation of the velocity field and temperature field inside the boiler furnace and obtain a real-time calculation model of the velocity field and temperature field inside the boiler furnace.

[0022] The purpose of the present invention can also be achieved through the following technical solutions.

[0023] The method for zero discharge of desulfurization wastewater from an intelligent coal-fired power generation unit of the present invention comprises the following steps:

[0024] S1: The DCS system collects the operation data of the coal-fired power generation unit in real time, including the operation load of the boiler, the operation coal quality, the total coal quantity, the primary and secondary air volume, the primary and secondary air temperature, the oxygen content at the economizer outlet, the furnace flue gas temperature, the furnace flue gas negative pressure, the steam temperature at the outlet of each heating surface, the steam flow at the outlet of each heating surface, the steam pressure at the outlet of each heating surface, the desuperheating water flow, and the damper opening;

[0025] S2: The data processing system analyzes and processes the operating data collected by the DCS system, extracts effective operating data in real time and transmits it to the intelligent control system;

[0026] S3: The intelligent control system calculates the total injection volume of desulfurized wastewater and the injection volume, injection angle and injection speed of each spray gun in real time according to the effective operation data transmitted by the data processing system, and controls the desulfurized wastewater centrifugal pump, total flow valve, branch flow valve and each spray gun in real time according to these calculated data, so as to spray the desulfurized wastewater in the sedimentation tank into the boiler.

[0027] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0028] Compared with the traditional three-unit box process, the present invention saves costs, reduces the amount of equipment inspection and maintenance, and can harmlessly treat the injected desulfurization wastewater. At the same time, the optimal injection amount and optimal injection angle of each injection position calculated based on numerical simulation technology effectively adjust the smoke temperature distribution in the furnace, reduce the temperature distribution difference of the medium in the furnace, and help reduce the amount of cooling water. It will not have an adverse effect on the operation of the coal-fired power generation unit, and provides an effective way for sewage treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of the zero-emission system for desulfurization wastewater of the intelligent coal-fired power generation unit of the present invention.

[0030] Figure 2 This is a schematic diagram of the desulfurization wastewater injection location for a 600MW wall-type hedge boiler in a power plant.

[0031] Figure numerals: 1-boiler, 2-dust collector, 3-induced draft fan, 4-desulfurization tower, 5-chimney, 6-sedimentation tank, 7-desulfurization wastewater centrifugal pump, 8-DCS system, 9-data processing system, 10-intelligent control system, 11-flow valve. Pipeline, Electrical connection, Flue. DETAILED DESCRIPTION

[0032] The technical solution of the present invention is clearly and completely described below in conjunction with the drawings and embodiments. The described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0033] like Figure 1 As shown, the intelligent coal-fired power generation unit desulfurization wastewater zero emission system of the present invention mainly includes a unit flue gas system, a sedimentation tank 6, a desulfurization wastewater transportation system, a DCS system 8, a data processing system 9, an intelligent control system 10, etc.

[0034] The unit flue gas system includes a boiler 1, a dust collector 2, an induced draft fan 3, a desulfurization tower 4, and a chimney 5 in a coal-fired power generation unit connected in sequence through a flue, and the lower discharge port of the desulfurization tower 4 is connected to a sedimentation tank 6 through a conveying pipeline. The sedimentation tank 6 not only filters the water-insoluble substances in the desulfurization wastewater generated by the desulfurization tower 4 by natural sedimentation, but also adds an ultrafiltration membrane to further improve the filtering effect, and temporarily stores a certain quality of desulfurization wastewater for subsequent treatment.

[0035] The desulfurization wastewater transportation system is used to transport the desulfurization wastewater initially filtered in the sedimentation tank 6 to various required locations, and mainly includes a desulfurization wastewater centrifugal pump 7, a total flow valve 11, and a branch flow valve 12. The inlet of the centrifugal pump 7 is connected to the liquid outlet of the sedimentation tank 6 through a delivery pipeline, the outlet of the centrifugal pump 7 is connected to the inlet of the total flow valve 11 through a delivery pipeline, and the outlet of the total flow valve 11 is connected to each spray gun arranged on the side wall of the boiler 1 through a branch pipeline, and each branch pipeline is provided with a branch flow valve 12.

[0036] In the above system, preferably, the spray gun is located between the burnout wind and the flame folding angle of the front wall of the boiler 1. The spray gun spray position between the burnout wind and the flame folding angle is selected according to the actual operation state of the boiler on site, combined with the temperature field and velocity field calculated by numerical simulation under different loads to select the best injection position. This example combines the temperature field and velocity field results of different loads calculated by on-site numerical calculation to determine that the injection position is located between the burnout wind and the flame folding angle of the front wall. In addition to ensuring a sufficiently high cross-sectional heat load to facilitate the evaporation and solidification of low-temperature wastewater in a very short time, this area is also arranged before the flame folding angle to facilitate the full mixing of wastewater solidification particles and ash particles, thereby improving the uniformity of salt content in ash and slag. The desulfurization wastewater transportation system transports the desulfurization wastewater that has been initially filtered in the sedimentation tank 6 to the injection position between the burnout wind and the flame folding angle at the front of the boiler furnace through the desulfurization wastewater centrifugal pump 7 and the transportation pipeline, and can be injected into the furnace at a certain pressure, and can control the total flow of the desulfurization wastewater and the flow of each injection position in real time through the total flow valve 11 and each branch flow valve 12. In addition, the arrangement of several spray guns in this area can also ensure a higher furnace temperature during the low-load period of the coal-fired power generation unit. The spraying and drying of low-temperature wastewater is not affected by the boiler output, and the system can be put into use under full-load conditions. The spray guns are arranged in 2 to 3 layers, with 2 to 4 spray guns on each layer. The number of spray guns on each layer is the same or different. The position and number of spray guns are determined according to the actual operating status of the on-site boiler, combined with the temperature field and velocity field calculated by numerical simulation under different loads, such as Figure 2 The layout example shown is that there are 3 spray guns on the upper layer and 2 spray guns on the lower layer. Figure 2 Part A is the spray gun mounting hole, part B is the burnout air outlet, and part C is the flame folding angle.

[0037] In the above system, preferably, the spray angle of the nozzle of the spray gun can be automatically adjusted. According to the temperature field distribution state in the boiler furnace, the spray angle can be adjusted to the position of the higher temperature zone to achieve balanced temperature distribution. The adjustable range is 45° to 135° with the vertical water-cooled wall of the front wall.

[0038] In the above system, preferably, the nozzle of the spray gun is an atomizing nozzle, and the nozzle adopts a multi-hole arrangement. The nozzle area can be automatically adjusted. The number of nozzle holes is adjusted according to the temperature distribution in the boiler furnace to realize the regulation of the nozzle injection speed. Precise positioning injection can also be achieved for a farther position to ensure sufficient mixing of the desulfurization wastewater and the flue gas and a good evaporation effect.

[0039] The DCS system 8 is used to collect the operation data of the coal-fired power generation unit in real time, mainly including the operation load of the boiler 1, the operation coal quality, the total coal quantity, the primary and secondary air volume, the primary and secondary air temperature, the oxygen content at the economizer outlet, the furnace flue gas temperature, the furnace flue gas negative pressure, the steam temperature at the outlet of each heating surface, the steam flow at the outlet of each heating surface, the steam pressure at the outlet of each heating surface, the cooling water flow, the damper opening, etc. The data processing system 9 is used to analyze and process the operation data collected by the DCS system 8, and extract the effective operation data in real time and transmit it to the intelligent control system 10. The intelligent control system 10 calculates the total injection amount of the desulfurization wastewater and the injection amount, injection angle, and injection speed of each spray gun in real time according to the effective operation data transmitted by the data processing system 9, and controls the desulfurization wastewater centrifugal pump 7, the total flow valve 11, the branch flow valve 12, and each spray gun in real time according to these calculated data.

[0040] In the above system, preferably, the data processing system 9 reads the real-time operation data of the boiler from the DCS system 8 through Modbus communication, analyzes, judges and processes the operation data collected by the DCS system 8, removes erroneous data, corrects deviation data, and obtains effective operation data. Specifically,

[0041] ① The data processing system 9 receives real-time operation data from the DCS system 8. These data contain key information such as timestamp, operation load and operation coal quality. The received real-time operation data is preliminarily verified to check whether the data format is correct, whether the timestamp is continuous, and whether there are obvious logical errors (such as negative temperature values, or pressure values ​​exceeding the equipment design range, etc.).

[0042] ② For data that can be directly judged as abnormal by preset rules during the preliminary verification process of step ① (such as extreme values ​​that exceed the possibility of physical equipment), it is directly regarded as erroneous data. For the above data directly judged as erroneous, the "last second data replacement method" is used to eliminate and replace it, that is, the normal operating data transmitted in the last second is used to replace the current erroneous data. This strategy is based on the assumption that data changes should be kept within a reasonable range in a short period of time, so the operating data of the last second can be used as a reasonable approximate data at the current moment.

[0043] ③For the data that cannot be directly judged correct by the preset rules during the preliminary verification process of step ①, compare it with the data under the same operating load conditions in the historical database. Calculate the deviation between the current data and the historical data, including but not limited to statistical indicators such as mean deviation and standard deviation deviation, to evaluate whether the current data significantly deviates from the normal range of historical data. Set a threshold. When the deviation of the current data exceeds this threshold, it is considered to be seriously deviated from the historical data, which may be caused by sensor failure, data transmission errors and other reasons. For cases that are judged to be seriously deviated from historical data, the "previous second data replacement method" is also used to eliminate and replace them to ensure the continuity and rationality of the data flow, and finally obtain valid operating data.

[0044] In the above system, preferably, the intelligent control system 10 acquires data from the data processing system 9 in real time, calculates in real time to form the real-time velocity field and temperature field inside the boiler furnace under the current operating conditions, and based on the velocity field, temperature field and effective operation data acquired in real time, with the goal of uniform furnace temperature distribution and velocity distribution, calculates in real time the total injection amount of desulfurization wastewater that meets the furnace operation requirements and the injection amount, injection angle, and injection speed of each spray gun, and feeds back the calculation results in real time to the desulfurization wastewater centrifugal pump 7, the total flow valve 11, and each branch flow valve 12 for flow control, as well as the control of the injection angle and injection speed of each spray gun, so as to realize the spraying of desulfurization wastewater from the desulfurization tower 4 in the coal-fired power generation unit into the boiler furnace.

[0045] The real-time velocity field and temperature field inside the boiler furnace in the intelligent control system 10 are real-time calculation models of the velocity field and temperature field inside the boiler furnace based on numerical simulation technology and neural network technology. The specific establishment process is as follows:

[0046] ① Use 3D CFD software to build a 1:1 model based on the specific structural dimensions of the boiler 1 on site, and use professional meshing tools (such as ANSYS ICEM) to mesh the established geometric model. Use the effective operating data of different working conditions of the real-time data processing system 9 to set the calculation boundary conditions, and obtain the heat flux density, temperature field and velocity field of each heating surface of the boiler 1 through cold and hot state calculations.

[0047] ②At the same time, a boiler steam-water system model is built at a 1:1 ratio according to the specific structural dimensions of the on-site steam-water system through one-dimensional thermal fluid software, and the temperature distribution of the medium on each heating surface is calculated based on the heat flux density of each heating surface obtained by three-dimensional CFD software.

[0048] ③ Import the temperature distribution data of each heating surface medium calculated by the one-dimensional thermal fluid software into the three-dimensional CFD software to optimize the heat flux density, temperature field and velocity field of each heating surface. In this way, the coupling calculation is iterated to achieve the coupling of the flue gas side and the steam-water side. Finally, the more accurate velocity field and temperature field inside the boiler furnace under typical working conditions are calculated, which improves the accuracy of the calculation inside the boiler furnace;

[0049] ④ Using the real-time effective operation data on site, check and calibrate the calculation results of the velocity field and temperature field inside the boiler furnace under typical working conditions obtained in step ③ (specifically, check and calibrate the real-time calculated values ​​of the velocity field and temperature field inside the boiler furnace) to improve the accuracy of the calculation model;

[0050] ⑤ Combined with the deep neural network, the calculation results and boundary conditions of the velocity field and temperature field inside the boiler furnace after the verification and calibration in step ④ are trained under full working conditions to realize the real-time calculation of the velocity field and temperature field inside the boiler furnace and obtain a real-time calculation model of the velocity field and temperature field inside the boiler furnace.

[0051] Based on the principle of the above-mentioned intelligent coal-fired generator set desulfurization wastewater zero discharge system, the present invention also proposes an intelligent coal-fired generator set desulfurization wastewater zero discharge method, which specifically includes the following steps:

[0052] S1: The DCS system 8 collects the operation data of the coal-fired power generation unit in real time, including the operation load of the boiler 1, the operation coal quality, the total coal quantity, the primary and secondary air volume, the primary and secondary air temperature, the oxygen quantity at the economizer outlet, the furnace flue gas temperature, the furnace flue gas negative pressure, the steam temperature at the outlet of each heating surface, the steam flow at the outlet of each heating surface, the steam pressure at the outlet of each heating surface, the desuperheating water flow, and the damper opening;

[0053] S2: The data processing system 9 analyzes and processes the operating data collected by the DCS system 8, extracts effective operating data in real time and transmits it to the intelligent control system 10;

[0054] S3: The intelligent control system 10 calculates the total injection volume of the desulfurized wastewater and the injection volume, injection angle, and injection speed of each spray gun in real time according to the effective operation data transmitted by the data processing system 9, and controls the desulfurized wastewater centrifugal pump 7, the total flow valve 11, the branch flow valve 12, and each spray gun in real time according to these calculated data, so as to spray the desulfurized wastewater in the sedimentation tank 6 into the boiler 1 to meet the furnace operation requirements of the boiler 1.

[0055] Although the functions and working processes of the present invention have been described above in conjunction with the accompanying drawings, the present invention is not limited to the above-mentioned specific functions and working processes. The above-mentioned specific implementation methods are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the purpose of the present invention and the claims, which are all within the protection of the present invention.

Claims

1. An intelligent coal-fired generator set desulfurization wastewater zero discharge system, characterized in that: It includes a unit flue gas system, a sedimentation tank (6), a desulfurization wastewater transportation system, a DCS system (8), a data processing system (9), and an intelligent control system (10); The unit flue gas system comprises a boiler (1), a dust collector (2), an induced draft fan (3), a desulfurization tower (4), and a chimney (5) in a coal-fired power generation unit which are sequentially connected through a flue, and the lower discharge port of the desulfurization tower (4) is connected to a sedimentation tank (6) through a conveying pipeline; The desulfurization wastewater transportation system comprises a desulfurization wastewater centrifugal pump (7), a total flow valve (11), and a branch flow valve (12); the inlet of the centrifugal pump (7) is connected to the liquid outlet of the sedimentation tank (6) through a delivery pipeline; the outlet of the centrifugal pump (7) is connected to the inlet of the total flow valve (11) through a delivery pipeline; the outlet of the total flow valve (11) is connected to each spray gun arranged on the side wall of the boiler (1) through a branch pipeline; and each branch pipeline is provided with a branch flow valve (12); The DCS system (8) is used to collect the operation data of the coal-fired power generation unit in real time. The data processing system (9) is used to analyze and process the operation data collected by the DCS system (8), extract effective operation data in real time and transmit it to the intelligent control system (10). The intelligent control system (10) calculates the total injection amount of desulfurized wastewater and the injection amount, injection angle and injection speed of each spray gun in real time based on the effective operation data transmitted by the data processing system (9), and controls the desulfurized wastewater centrifugal pump (7), the total flow valve (11), the branch flow valve (12) and each spray gun in real time based on the calculated data.

2. The intelligent coal-fired power generation unit desulfurization wastewater zero discharge system according to claim 1 is characterized in that: The sedimentation tank (6) is used to filter the substances that are hardly soluble in water in the desulfurization wastewater generated by the desulfurization tower (4).

3. The intelligent coal-fired power generation unit desulfurization wastewater zero discharge system according to claim 1 is characterized in that: The spray guns are located between the burnout wind and the flame folding angle of the front wall of the boiler (1), and are arranged in 2 to 3 layers, with 2 to 4 spray guns on each layer, and the number of spray guns on each layer is the same or different.

4. The intelligent coal-fired power generation unit desulfurization wastewater zero discharge system according to claim 3 is characterized in that: The spray angle of the spray gun nozzle can be automatically adjusted. According to the temperature field distribution state in the boiler furnace, the spray angle can be adjusted to the position of the higher temperature zone to achieve balanced temperature distribution. The adjustable range is 45° to 135° with the vertical water-cooled wall of the front wall.

5. The intelligent coal-fired power generation unit desulfurization wastewater zero discharge system according to claim 3 is characterized in that: The nozzle of the spray gun is an atomizing nozzle, which adopts a multi-hole arrangement. The nozzle area can be automatically adjusted. The number of nozzle holes is adjusted according to the temperature distribution in the boiler furnace to achieve the regulation of the nozzle injection speed.

6. The intelligent coal-fired power generation unit desulfurization wastewater zero discharge system according to claim 1 is characterized in that: The DCS system (8) collects in real time the operating data of the coal-fired power generation unit, including the operating load of the boiler, the operating coal quality, the total coal quantity, the primary and secondary air volumes, the primary and secondary air temperatures, the oxygen content at the economizer outlet, the furnace flue gas temperature, the furnace flue gas negative pressure, the steam temperature at the outlet of each heating surface, the steam flow rate at the outlet of each heating surface, the steam pressure at the outlet of each heating surface, the cooling water flow rate, and the damper opening.

7. The intelligent coal-fired power generation unit desulfurization wastewater zero discharge system according to claim 1 is characterized in that: The data processing system (9) reads the real-time operation data of the boiler from the DCS system (8) through the Modbus communication mode, analyzes, judges and processes the operation data collected by the DCS system (8), eliminates erroneous data, corrects deviation data, and obtains effective operation data.

8. The intelligent coal-fired power generation unit desulfurization wastewater zero discharge system according to claim 1 is characterized in that: The intelligent control system (10) acquires data from the data processing system (9) in real time, calculates in real time to form a real-time velocity field and temperature field inside the boiler furnace under the current working conditions, and based on the velocity field, temperature field and the effective operation data acquired in real time, with the goal of uniform furnace temperature distribution and velocity distribution, calculates in real time the total injection amount of desulfurized wastewater that meets the furnace operation requirements and the injection amount, injection angle and injection speed of each spray gun, and feeds back the calculation results in real time to the desulfurized wastewater centrifugal pump (7), the total flow valve (11) and each branch flow valve (12) for flow control, as well as the injection angle and injection speed control of each spray gun, so as to realize the desulfurized wastewater from the desulfurization tower (4) in the coal-fired power generation unit being sprayed into the boiler furnace.

9. The intelligent coal-fired power generation unit desulfurization wastewater zero discharge system according to claim 8 is characterized in that: The real-time velocity field and temperature field inside the boiler furnace in the intelligent control system (10) are real-time calculation models of the velocity field and temperature field inside the boiler furnace built based on numerical simulation technology and neural network technology. The establishment process is as follows: ① Use 3D CFD software to carry out 1:1 modeling according to the specific structural dimensions of the boiler on site, and use the meshing tool to mesh the established geometric model; use the effective operating data of different working conditions of the real-time data processing system to set the calculation boundary conditions, and obtain the heat flux density, temperature field and velocity field of each heating surface of the boiler through cold and hot state calculations. ② Use one-dimensional thermal fluid software to build a boiler steam-water system model at a ratio of 1:1 based on the specific structural dimensions of the on-site steam-water system, and calculate the temperature distribution of the medium on each heating surface of the boiler based on the heat flux density of each heating surface calculated by three-dimensional CFD software; ③ Import the temperature distribution data of each heating surface medium calculated by the one-dimensional thermal fluid software into the three-dimensional CFD software to optimize the heat flux density, temperature field and velocity field of each heating surface, and iterate the coupling calculation to achieve the coupling of the flue gas side and the steam-water side, and finally calculate and obtain the velocity field and temperature field inside the boiler furnace under typical working conditions; ④ Using the real-time effective operation data on site, check and calibrate the calculation results of the velocity field and temperature field inside the boiler furnace under typical working conditions obtained in step ③; ⑤ Combined with the deep neural network, the calculation results and boundary conditions of the velocity field and temperature field inside the boiler furnace after the verification and calibration in step ④ are trained under full working conditions to realize the real-time calculation of the velocity field and temperature field inside the boiler furnace and obtain a real-time calculation model of the velocity field and temperature field inside the boiler furnace.

10. A method for zero discharge of desulfurization wastewater based on the intelligent coal-fired power generation unit zero discharge system for desulfurization wastewater according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1: The DCS system (8) collects the operating data of the coal-fired power generation unit in real time, including the operating load of the boiler (1), the operating coal quality, the total coal quantity, the primary and secondary air volume, the primary and secondary air temperature, the oxygen content at the economizer outlet, the furnace flue gas temperature, the furnace flue gas negative pressure, the steam temperature at the outlet of each heating surface, the steam flow rate at the outlet of each heating surface, the steam pressure at the outlet of each heating surface, the desuperheating water flow rate, and the damper opening; S2: The data processing system (9) analyzes and processes the operation data collected by the DCS system (8), extracts effective operation data in real time and transmits it to the intelligent control system (10); S3: The intelligent control system (10) calculates in real time the total injection amount of the desulfurized wastewater and the injection amount, injection angle, and injection speed of each spray gun based on the effective operation data transmitted by the data processing system (9), and controls the desulfurized wastewater centrifugal pump (7), the total flow valve (11), the branch flow valve (12), and each spray gun in real time based on these calculated data, so as to spray the desulfurized wastewater in the sedimentation tank (6) into the boiler (1).

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