Method and system for controlling PM emission concentration of coal-fired unit

Abstract

The invention discloses a method and system for controlling PM emission concentration of a coal-fired unit, and belongs to the technical field of coal-fired power generation. According to the method for controlling the PM emission concentration of the coal-fired unit, the inlet PM concentration, the slurry circulation flow and the inlet flue gas flow velocity of a wet flue gas desulfurization system, the flue gas temperature and the flow velocity of an outlet of a low-temperature economizer and the real-time load of the coal-fired unit are comprehensively considered, and an accurate feed-forward instruction is generated; according to the method, a feedforward instruction and a main instruction calculated by a PID (Proportion Integration Differentiation) control algorithm are combined to dynamically and accurately adjust the dust removal voltage of the electric dust removal system, so that the PM emission concentration of a coal-fired unit is effectively controlled, and the coal-fired unit can keep stable emission performance even in a frequent load change or low load operation state.

Description

Technical Field

[0001] The present invention relates to the technical field of coal-fired power generation, and particularly relates to a method and system for controlling the PM emission concentration of a coal-fired unit. Background Art

[0002] With the rapid development of renewable energy, especially the large-scale grid connection of wind energy and solar energy, the role of coal-fired units in the future energy system will change. They not only need to continuously and stably supply electricity, but also will more often undertake the tasks of peak shaving and frequency modulation to adapt to the intermittency and uncertainty of new energy power generation, so as to ensure the stable operation of the entire power grid. This change means that coal-fired units will have to frequently and rapidly adjust within a large load range to adapt to the demand fluctuations of the power grid, and thus accommodate more wind energy and solar energy.

[0003] However, during the frequent load change and low load operation of coal-fired units, significant changes will occur in their combustion processes and flue gas emission characteristics. Especially during the rapid load change process, the combustion state in the furnace is unstable, resulting in large fluctuations in flue gas composition and temperature, which poses a severe challenge to the emission control of particulate matter (PM) in coal-fired units. The emission of particulate matter not only affects the ambient air quality, but may also pose a threat to the operation efficiency and safety of the unit itself.

[0004] In order to effectively control the particulate matter concentration in the flue gas of coal-fired units, an electrostatic precipitator system is widely used in coal-fired power plants. The electrostatic precipitator system makes the particulate matter in the flue gas charged by applying a high-voltage electric field, and is collected on the electrode plates under the action of the electric field force, thereby realizing the effective removal of particulate matter. This system has a high dust removal efficiency under stable operating conditions and can meet strict environmental protection emission standards. At the same time, the wet flue gas desulfurization system is also one of the indispensable air pollutant control devices in coal-fired units. This system can not only efficiently remove sulfur dioxide (SO2) in the flue gas, but also synergistically remove PM particulate matter to a certain extent.

[0005] However, when the coal-fired unit is in the state of frequent load change operation or low load operation, the flue gas temperature and flow rate at the inlet of the electrostatic precipitator system will fluctuate greatly. Such fluctuations not only affect the electric field distribution and particulate matter charging efficiency inside the electrostatic precipitator, but may also lead to ash accumulation on the electrode plates and a decrease in the ash cleaning efficiency, thus affecting the PM particulate matter emission concentration of the coal-fired unit. In addition, the operating parameters of the wet flue gas desulfurization system will also fluctuate greatly due to load changes, further increasing the difficulty of controlling the particulate matter concentration of the coal-fired unit.

[0006] Therefore, when the coal-fired unit is in the state of frequent load change operation or low load operation, how to propose a method that can effectively control the PM particulate matter emission concentration of the coal-fired unit has become a technical problem that needs to be solved urgently by those skilled in the art. Summary of the Invention

[0007] The object of the present invention is to provide a method and system for controlling the PM emission concentration of a coal-fired unit, aiming to solve the technical problem that in the prior art, it is difficult to effectively control the PM emission concentration due to the frequent load change operation or low load operation of the coal-fired unit.

[0008] The present invention solves the above technical problems through the following technical solutions: A method for controlling the PM emission concentration of a coal-fired unit, comprising the following steps: Step 1, calculate a first feedforward command of the electrostatic precipitator system based on the inlet PM concentration, slurry circulation flow rate and inlet flue gas flow rate of the wet flue gas desulfurization system of the coal-fired unit ; Calculate a second feedforward command of the electrostatic precipitator system based on the outlet flue gas temperature and outlet flue gas flow rate of the low-temperature economizer of the coal-fired unit ; Calculate a third feedforward command of the electrostatic precipitator system based on the load of the coal-fired unit ; Step 2, calculate a main command of the dust removal voltage of the electrostatic precipitator system through a PID control algorithm based on the deviation between the outlet PM concentration and the set value of the outlet PM concentration of the wet flue gas desulfurization system of the coal-fired unit; Step 3, calculate a dust removal voltage command of the electrostatic precipitator system through the main command of the dust removal voltage, the first feedforward command , the second feedforward command and the third feedforward command to realize dynamic adjustment of the dust removal voltage of the electrostatic precipitator system. The present invention is further improved in that: the first feedforward command

[0009] is specifically: wherein,

[0010] is the inlet PM concentration of the wet flue gas desulfurization system of the coal-fired unit; is the slurry circulation flow rate of the wet flue gas desulfurization system of the coal-fired unit; is the inlet flue gas flow rate of the wet flue gas desulfurization system of the coal-fired unit; is the inlet flue gas flow rate of the wet flue gas desulfurization system of the coal-fired unit; is a calculation coefficient and is a constant.

[0011] The present invention is further improved in that: the second feedforward command is specifically:

[0012] wherein, is the outlet flue gas temperature of the low-temperature economizer of the coal-fired unit; is the outlet flue gas velocity of the low-temperature economizer of the coal-fired unit; is a calculation coefficient and is a constant.

[0013] A further improvement of the present invention lies in: the third feedforward command Specifically:

[0014] Among them, is the load of the coal-fired unit; is a calculation coefficient and is a constant.

[0015] A further improvement of the present invention lies in: the dust removal voltage command of the electrostatic precipitator system Specifically:

[0016] Among them, is the deviation between the outlet PM concentration and the set value of the outlet PM concentration of the wet flue gas desulfurization system of the coal-fired unit; is a calculation coefficient and is a constant.

[0017] A further improvement of the present invention lies in: the dust removal voltage command of the electrostatic precipitator system Meets the following conditions:

[0018] Among them, is the breakdown voltage of the electrostatic precipitator system, The value range of is: 100 ~ 120 kV; is the onset voltage of the electrostatic precipitator system, The value range of is 20~30 kV.

[0019] A further improvement of the present invention lies in: the inlet PM concentration of the wet flue gas desulfurization system of the coal-fired unit meets the following conditions:

[0020] Among them, is the minimum value of the inlet PM concentration of the wet flue gas desulfurization system of the coal-fired unit, The value range of is: 3~5 mg m -3 ; is the maximum value of the inlet PM concentration of the wet flue gas desulfurization system of the coal-fired unit, The value range of is 80~90 mg m -3 .

[0021] A further improvement of the present invention lies in: the slurry circulation flow rate of the wet flue gas desulfurization system of the coal-fired unit meets the following conditions:

[0022] Among them, is the sum of the rated flow rates of the slurry circulation pumps in the wet flue gas desulfurization system of the coal-fired unit; is the adjustment coefficient of the frequency converter of the slurry circulation pump in the wet flue gas desulfurization system of the coal-fired unit, and the value range of is: 0.5 - 0.6.

[0023] A further improvement of the present invention lies in that: the set value of the PM concentration at the outlet of the wet flue gas desulfurization system of the coal-fired unit is 4 - 6 mg m -3 .

[0024] The present invention also provides a system for controlling the PM emission concentration of a coal-fired unit. The system includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of the method for controlling the PM emission concentration of a coal-fired unit as described above.

[0025] Compared with the prior art, the positive and progressive effects of the present invention are as follows: The method for controlling the PM emission concentration of a coal-fired unit provided by the present invention comprehensively considers the inlet PM concentration, slurry circulation flow rate, inlet flue gas flow rate of the wet flue gas desulfurization system, as well as the flue gas temperature and flow rate at the outlet of the low-temperature economizer, and the real-time load of the coal-fired unit, generates an accurate feedforward command, and combines the feedforward command with the main command calculated by the PID control algorithm to achieve dynamic and accurate adjustment of the dust removal voltage of the electrostatic precipitator system, thereby effectively controlling the PM emission concentration of the coal-fired unit, so that the coal-fired unit can maintain stable emission performance even under frequent load changes or low-load operating conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings in the specification are used to provide a further understanding of the present invention, and constitute a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0027] Figure 1 is a schematic flow chart of a method for controlling the PM emission concentration of a coal-fired unit according to the present invention; Figure 2 is a schematic diagram of the effect of a method for controlling the PM emission concentration of a coal-fired unit according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

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

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

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

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

[0032] In addition, it should be noted that unless otherwise clearly specified and defined, if terms such as "set", "installed", "connected", "connected" are understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] The following further detailed description of the present invention with reference to the accompanying drawings and specific embodiments is an explanation rather than a limitation of the present invention.

[0034] See Figure 1 , a method for controlling the PM emission concentration of a coal-fired unit, comprising the following steps: Step 1: Calculate a first feedforward command of the electrostatic precipitator system based on the inlet PM concentration, slurry circulation flow rate and inlet flue gas flow rate of the wet flue gas desulfurization system of the coal-fired unit ; Based on the outlet flue gas temperature and outlet flue gas flow rate of the low-temperature economizer of the coal-fired unit, the second feedforward command of the electrostatic precipitation system is calculated ; Based on the load of the coal-fired unit, the third feedforward command of the electrostatic precipitation system is calculated ; Step 2: Based on the deviation between the outlet PM concentration of the wet flue gas desulfurization system of the coal-fired unit and the set value of the outlet PM concentration, the main command of the dust removal voltage of the electrostatic precipitation system is calculated through the PID control algorithm; Step 3: Through the main command of the dust removal voltage, the first feedforward command , the second feedforward command and the third feedforward command , the dust removal voltage command of the electrostatic precipitation system is calculated , realizing dynamic adjustment of the dust removal voltage of the electrostatic precipitation system.

[0035] The method for controlling the PM emission concentration of a coal-fired unit provided by the present invention comprehensively considers the inlet PM concentration, slurry circulation flow rate, inlet flue gas flow rate of the wet flue gas desulfurization system, as well as the flue gas temperature and flow rate at the outlet of the low-temperature economizer, and the real-time load of the coal-fired unit, generates accurate feedforward commands, and combines the feedforward commands with the main commands calculated by the PID control algorithm to realize dynamic and accurate adjustment of the dust removal voltage of the electrostatic precipitation system, thereby effectively controlling the PM emission concentration of the coal-fired unit, so that the coal-fired unit can maintain stable emission performance even under frequent load changes or low-load operating conditions.

[0036] Specifically, the first feedforward command is specifically:

[0037] Among them, is the inlet PM concentration of the wet flue gas desulfurization system of the coal-fired unit; is the slurry circulation flow rate of the wet flue gas desulfurization system of the coal-fired unit; is the inlet flue gas flow rate of the wet flue gas desulfurization system of the coal-fired unit; is a calculation coefficient and is a constant.

[0038] Specifically, the second feedforward command is specifically:

[0039] Among them, is the outlet flue gas temperature of the low-temperature economizer of the coal-fired unit; is the outlet flue gas flow rate of the low-temperature economizer of the coal-fired unit; is a calculation coefficient and is a constant.

[0040] Specifically, the third feedforward command is specifically:

[0041] wherein, is the load of the coal-fired unit; is a calculation coefficient and is a constant.

[0042] Specifically, the dust removal voltage command of the ESP system is specifically:

[0043] wherein, is the deviation between the outlet PM concentration of the wet flue gas desulfurization system of the coal-fired unit and the set value of the outlet PM concentration; is a calculation coefficient and is a constant.

[0044] Specifically, the dust removal voltage command of the ESP system meets the following conditions:

[0045] wherein, is the breakdown voltage of the ESP system, and the value range of is: 100 - 120 kV; is the onset voltage of the ESP system, and the value range of is 20 - 30 kV.

[0046] Specifically, the inlet PM concentration of the wet flue gas desulfurization system of the coal-fired unit meets the following conditions:

[0047] wherein, is the minimum value of the inlet PM concentration of the wet flue gas desulfurization system of the coal-fired unit, and the value range of is: 3 - 5 mg / m -3 ; is the maximum value of the inlet PM concentration of the wet flue gas desulfurization system of the coal-fired unit, and the value range of is 80 - 90 mg / m -3 .

[0048] Specifically, the slurry circulation flow rate of the wet flue gas desulfurization system of the coal-fired unit meets the following conditions:

[0049] wherein, is the sum of the rated flow rates of the slurry circulation pumps of the wet flue gas desulfurization system of the coal-fired unit; is the adjustment coefficient of the frequency converter of the slurry circulation pump in the wet flue gas desulfurization system of a coal-fired unit. The value range of is: 0.5 - 0.6.

[0050] Specifically, the set value of the PM concentration at the outlet of the wet flue gas desulfurization system of the coal-fired unit is 4 - 6 mg m -3 .

[0051] The present invention also provides a system for controlling the PM emission concentration of a coal-fired unit. The system includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the method for controlling the PM emission concentration of the coal-fired unit as described above are implemented.

[0052] Example 1 A method for controlling the PM emission concentration of a coal-fired unit includes the following steps: Step 1: Based on the PM concentration at the inlet of the wet flue gas desulfurization system of the coal-fired unit, the slurry circulation flow rate, and the inlet flue gas velocity, calculate the first feedforward command of the electrostatic precipitator system ; The first feedforward command Specifically:

[0053] In the formula, is the first feedforward command, kV; is the PM concentration at the inlet of the wet flue gas desulfurization system, mg m -3 ; is the slurry circulation flow rate of the wet flue gas desulfurization system, m 3 h -1 ; is the inlet flue gas velocity of the wet flue gas desulfurization system, m s -1 ; is the calculation coefficient, which is a constant; Based on the outlet flue gas temperature and the outlet flue gas velocity of the low-temperature economizer of the coal-fired unit, calculate the second feedforward command of the electrostatic precipitator system ; The second feedforward command Specifically:

[0054] In the formula, is the second feedforward command, kV; is the outlet flue gas temperature of the low-temperature economizer of the coal-fired unit, °C; is the outlet flue gas velocity of the low-temperature economizer of the coal-fired unit, m s -1 ; is the calculation coefficient, which is a constant; Based on the load of the coal-fired unit, the third feedforward command of the electrostatic precipitator system is calculated. ; The third feedforward command Specifically:

[0055] is the third feedforward command, kV; is the load of the coal-fired unit, MW; is the calculation coefficient, which is a constant.

[0056] Step 2: Based on the deviation between the outlet PM concentration and the set value of the outlet PM concentration of the wet flue gas desulfurization system of the coal-fired unit, the main command of the dust removal voltage of the electrostatic precipitator system is calculated through the PID control algorithm; Step 3: Through the main command of the dust removal voltage, the first feedforward command , the second feedforward command and the third feedforward command , the dust removal voltage command of the electrostatic precipitator system is calculated to realize the dynamic adjustment of the dust removal voltage of the electrostatic precipitator system.

[0057] The dust removal voltage command of the electrostatic precipitator system is specifically:

[0058] In the formula, is the dust removal voltage command of the electrostatic precipitator system, kV; is the deviation between the outlet PM concentration of the wet flue gas desulfurization system and its set value, mg m -3 ; is the calculation coefficient, which is a constant.

[0059] When controlling the PM emission concentration, the method of adjusting the dust removal voltage of the electrostatic precipitator system of the coal-fired unit only according to the load of the coal-fired unit is called the traditional control method, and the control method of the present invention is called the optimized control method. Compared with the traditional control method, the optimized control method of the present invention has the following specific advantages: The method for controlling the PM emission concentration of the coal-fired unit in the present invention, while considering the load change of the coal-fired unit, also considers the changes in the outlet flue gas temperature and outlet flue gas flow rate of the low-temperature economizer of the coal-fired unit, as well as the changes in the inlet PM concentration, slurry circulation flow rate and inlet flue gas flow rate of the wet flue gas desulfurization system, so as to achieve precise control of the PM emission concentration of the coal-fired unit.

[0060] During the load change process of the coal-fired unit from 75% to 50% THA, the change law of the PM emission concentration is as Figure 2As shown, it can be found that after adopting the optimized control method, the control effect of the PM emission concentration of the coal-fired unit has been improved. During the load change process, the cumulative deviation between the PM emission concentration and the set value has decreased by 88.58%, and the maximum deviation between the PM emission concentration and the set value has decreased by 79.46%. This method can effectively control the PM emission concentration of the coal-fired unit, enabling the coal-fired unit to maintain stable emission performance even under frequent load changes or low-load operating conditions.

[0061] The method for controlling the PM emission concentration of a coal-fired unit provided by the present invention takes into account the influence of changes in desulfurization operating parameters on the PM emission concentration of the coal-fired unit. The PM concentration at the outlet of the wet flue gas desulfurization system is adjusted through the dust removal voltage. Among them, the deviation between the PM concentration at the outlet of the wet flue gas desulfurization system and its set value is obtained through PID calculation to obtain the main command of the dust removal voltage of the electrostatic precipitator system. Its feedforward commands include the first feedforward command, the second feedforward command, and the third feedforward command. Among them, the third feedforward command is obtained based on the unit load; the second feedforward command is obtained based on the changes in the flue gas temperature and flow rate at the outlet of the low-temperature economizer, which can make the change in the dust removal voltage adapt to the fluctuations in the flue gas temperature and flow rate during the load change process of the coal-fired unit; the first feedforward command is obtained based on the changes in the PM concentration at the inlet of the flue gas desulfurization system, the desulfurization slurry circulation flow rate, and the flue gas flow rate at the inlet of the desulfurization system, which can make the adjustment of the dust removal voltage during the load change process adapt to the change in the PM co-removal efficiency of the desulfurization system caused by the change in the desulfurization system operating parameters. The control method of the present invention can effectively address the problem of difficult PM emission control caused by large fluctuations in flue gas temperature, flow rate, and desulfurization system parameters during the frequent and rapid load change process of coal-fired units.

[0062] Finally, it should be noted that the above-listed embodiments exist merely as one or more specific manifestations of the technical solution of the present invention. Their purpose is to clearly elaborate the concept, principle, and application method of the present invention through specific examples, rather than intending to limit the protection scope of the present invention to these specific embodiments. In fact, the true value of the present invention lies in the proposed technical idea and innovation point, rather than its manifestation form or implementation means.

[0063] For those of ordinary skill in the art in the relevant technical field, after deeply reading and understanding the technical solution of the present invention, they are fully capable of making various forms of changes, modifications, or equivalent replacements to the specific implementation manners of the invention based on their own professional knowledge and skills. These changes may include, but are not limited to: adjusting the value range of technical parameters, optimizing the algorithm process to improve efficiency, replacing some technical components to achieve better compatibility or reduce costs, etc. As long as the changed technical solutions still substantially maintain the technical features required to be protected by the original invention, that is, they can still achieve the core functions and effects of the present invention, then these changes should be regarded as falling within the protection scope of the pending claims of the present invention.

[0064] In addition, with the continuous progress and development of technology, new technical means and methods are constantly emerging, which also provides broad space for the further improvement and perfection of the present invention. Therefore, the protection scope of the present invention should also include those reasonable and foreseeable improvements and expansions based on the prior art. As long as these improvements and expansions do not depart from the basic principles and core concepts of the present invention, they should be regarded as equivalents of the present invention and are equally protected by the patent right.

Claims

1. A method for controlling PM emission concentration of a coal-fired unit, characterized in that: The following steps are involved: Step 1: Based on the inlet PM concentration, slurry circulation flow rate and inlet flue gas flow rate of the wet flue gas desulfurization system of the coal-fired unit, the first feedforward instruction of the electrostatic precipitator system is calculated. ; Based on the outlet flue gas temperature and outlet flue gas flow rate of the low-temperature economizer of the coal-fired unit, the second feedforward instruction of the electrostatic precipitator system is calculated ; Based on the load of the coal-fired unit, the third feedforward instruction of the electrostatic precipitator system is calculated ; Step 2: Based on the deviation between the outlet PM concentration of the wet flue gas desulfurization system of the coal-fired unit and the outlet PM concentration set value, the dust removal voltage main instruction of the electrostatic precipitator system is calculated through the PID control algorithm; Step 3: Use the dust removal voltage main instruction and the first feedforward instruction , the second feedforward instruction And the third feedforward instruction , calculate the dust removal voltage instruction of the electrostatic precipitator system , to achieve dynamic adjustment of the dust removal voltage of the electrostatic precipitator system.

2. A method for controlling PM emission concentration of a coal-fired unit according to claim 1, characterized in that: First feedforward instruction Specifically: in, is the PM concentration at the inlet of the wet flue gas desulfurization system of the coal-fired unit; It is the slurry circulation flow rate of the wet flue gas desulfurization system of the coal-fired unit; The inlet flue gas flow rate of the wet flue gas desulfurization system of the coal-fired unit; is the calculation coefficient and is a constant.

3. A method for controlling PM emission concentration of a coal-fired unit according to claim 2, characterized in that: Second feedforward instruction Specifically: in, The outlet flue gas temperature of the low-temperature economizer of the coal-fired unit; The outlet flue gas velocity of the low-temperature economizer of the coal-fired unit; is the calculation coefficient and is a constant.

4. A method for controlling PM emission concentration of a coal-fired unit according to claim 3, characterized in that: The third feedforward instruction Specifically: in, is the load of the coal-fired unit; is the calculation coefficient and is a constant.

5. A method for controlling PM emission concentration of a coal-fired unit according to claim 4, characterized in that: Dust removal voltage instruction of electrostatic precipitator system Specifically: in, It is the deviation between the outlet PM concentration of the wet flue gas desulfurization system of the coal-fired unit and the set value of the outlet PM concentration; is the calculation coefficient and is a constant.

6. A method for controlling PM emission concentration of a coal-fired unit according to claim 1, characterized in that: Dust removal voltage instruction of electrostatic precipitator system Meet the following conditions: in, is the breakdown voltage of the electrostatic precipitator system, The value range is: 100 ~ 120 kV; is the corona inception voltage of the electrostatic precipitator system, The value range is 20~30 kV.

7. A method for controlling PM emission concentration of a coal-fired unit according to claim 1, characterized in that: The PM concentration at the inlet of the wet flue gas desulfurization system of the coal-fired unit meets the following conditions: in, is the minimum PM concentration at the inlet of the wet flue gas desulfurization system of the coal-fired unit, The value range is: 3~5 mg m -3 ; is the maximum PM concentration at the inlet of the wet flue gas desulfurization system of the coal-fired unit, The value range is 80~90 mg m -3 .

8. The method for controlling PM emission concentration of a coal-fired unit according to claim 1, characterized in that: The slurry circulation flow rate of the wet flue gas desulfurization system of the coal-fired unit meets the following conditions: in, It is the sum of the rated flows of the slurry circulation pumps in the wet flue gas desulfurization system of the coal-fired unit; It is the adjustment coefficient of the inverter of the slurry circulation pump of the wet flue gas desulfurization system of the coal-fired unit. The value range is: 0.5~0.

6.

9. The method for controlling PM emission concentration of a coal-fired unit according to claim 1, characterized in that: The outlet PM concentration of the wet flue gas desulfurization system of coal-fired units is set at 4~6 mg m -3 .

10. A system for controlling PM emission concentration of a coal-fired unit, characterized in that: The system includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the method for controlling PM emission concentration of a coal-fired unit as claimed in any one of claims 1 to 9 are implemented.

Images