Optimal calculation control method and system for economical efficiency of desulfurization system

Abstract

The invention discloses a desulfurization system economy optimal calculation control method and system, and relates to the technical field of wet flue gas desulfurization, and the method comprises the following steps: under the working conditions of load stability and inlet stability, calculating the calcium-sulfur ratio and desulfurization efficiency, and optimizing the limestone cost; establishing a relationship between the number of slurry circulating pumps put into operation and the flue gas amount and inlet sulfur dioxide concentration, and calculating water consumption and environmental protection tax cost; the total cost is calculated, and the minimum value of the most economical operation total cost function of the desulfurization system is solved. According to the economical efficiency optimal calculation control method for the desulfurization system, by calculating the calcium-sulfur ratio and the desulfurization efficiency, the operation economical efficiency and the long-term effect of the desulfurization system are improved, the overall operation cost is reduced by accurately calculating the water consumption and the environmental protection tax, and according to the solved optimal outlet sulfur dioxide concentration, the control system is used for controlling the economic efficiency optimal calculation of the desulfurization system. And the stability and the operation efficiency of the system are improved, and better effects are achieved in the aspects of operation economy, operation cost and operation efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of wet flue gas desulfurization, and in particular to a method for calculating and controlling the economic optimality of a desulfurization system. Background Art

[0002] As the world's environmental protection requirements become increasingly stringent, ultra-low emission technology for coal-fired power plants has become a hot topic. As the current mainstream flue gas desulfurization method, wet flue gas desulfurization technology is widely used in major power plants to achieve the goal of reducing sulfur dioxide emissions. This technology reacts limestone or lime slurry with sulfur dioxide in flue gas to generate gypsum and ultimately remove sulfur dioxide. In recent years, wet flue gas desulfurization technology has been continuously optimized, and its desulfurization efficiency and operating cost have become key factors affecting the economic efficiency of power plant operations, especially in the context of increasingly stringent national environmental protection policies, such as emission standards controlled at 35mg / m 3 The following requirements require coal-fired power plants to not only meet strict emission standards, but also to comprehensively optimize operating costs such as reducing electricity consumption, water consumption and limestone consumption.

[0003] Although the existing wet flue gas desulfurization system has been improved in efficiency, it still faces many challenges. First, the existing system generally adopts extensive management methods and lacks accurate cost accounting methods, especially in the optimization adjustment between limestone consumption and desulfurization efficiency. There is a lack of systematic analysis. Secondly, electricity consumption accounts for a high proportion of desulfurization costs, and the existing technology has failed to form an efficient model for optimizing the number of slurry circulation pumps, flue gas volume and sulfur dioxide concentration, resulting in insufficient optimization of electricity consumption. In addition, the collection of environmental protection taxes is in a gradient decreasing relationship with sulfur dioxide emission concentration. How to control the increase of other operating costs such as limestone and water consumption while maintaining low emission concentrations is also a problem that existing technologies are difficult to balance. Summary of the invention

[0004] In view of the above-mentioned problems, the present invention is proposed.

[0005] Therefore, the technical problem solved by the present invention is: the existing wet desulfurization method lacks accurate cost accounting, insufficient power consumption optimization, and how to optimize the operating costs such as limestone cost, power consumption and water consumption while meeting the requirements of ultra-low emissions.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions: a method for calculating and controlling the economic optimality of a desulfurization system, comprising calculating the calcium-sulfur ratio and the desulfurization efficiency under conditions of stable load and stable inlet, and optimizing the limestone cost; establishing the relationship between the number of slurry circulation pumps in operation and the flue gas volume and inlet sulfur dioxide concentration, and calculating the water consumption and environmental protection tax cost; calculating the total cost, and obtaining the minimum value of the most economical total cost function for the desulfurization system.

[0007] As a preferred solution of the desulfurization system economic optimal calculation and control method described in the present invention, the optimization of limestone cost includes calculating the limestone cost based on the sulfur dioxide concentration in the flue gas and the calcium-sulfur ratio of the desulfurization system. The limestone consumption is positively correlated with the inlet sulfur dioxide concentration. The higher the inlet sulfur dioxide concentration, the greater the demand for limestone. The lower the outlet sulfur dioxide concentration, the more limestone is consumed. When the outlet sulfur dioxide concentration decreases, the calcium-sulfur ratio increases, and the limestone consumption increases. The desulfurization efficiency and the outlet sulfur dioxide concentration are controlled to optimize the limestone cost. The limestone cost calculation is expressed as:

[0008]

[0009]

[0010] in, For limestone costs, is the limestone consumption, V RG is the flue gas volume flow rate, is the inlet sulfur dioxide concentration in the flue gas, is the sulfur dioxide emission concentration in flue gas, is the molar mass of calcium carbonate, is the molar mass of sulfur dioxide, F R is the purity of limestone, S t The limestone cost is proportional to the flue gas volume and the calcium-sulfur ratio, proportional to the inlet sulfur dioxide concentration, and inversely proportional to the outlet sulfur dioxide concentration.

[0011] As a preferred solution of the optimal calculation and control method for the economic efficiency of the desulfurization system described in the present invention, the calculation of the calcium-sulfur ratio and the desulfurization efficiency includes the ratio of the consumed calcium carbonate to the removed sulfur dioxide. When the pH value of the desulfurization tower and the quality of the limestone are determined, the ratio increases with the increase of the desulfurization efficiency. The desulfurization efficiency is changed under the conditions of stable load and stable inlet by changing the outlet sulfur dioxide test of the unit, the actual limestone consumption is counted, the gypsum sample is obtained, and the DCS data is saved during the test. The calcium-sulfur ratio and the desulfurization efficiency are calculated. The relationship between the calcium-sulfur ratio and the desulfurization efficiency is expressed as follows:

[0012]

[0013] S T =f(η)

[0014]

[0015] Among them, η is the desulfurization efficiency, which represents the removal rate of sulfur dioxide in the system, and f1 is the limestone consumption function.

[0016] As a preferred solution of the optimal calculation and control method for the economic efficiency of the desulfurization system described in the present invention, the relationship between the number of slurry circulation pumps in operation, the flue gas volume and the inlet sulfur dioxide concentration includes calculating the power consumption cost, which is affected by the operating status of the slurry circulation pump and the oxidation fan, and is expressed as:

[0017] P 电 =P 泵 ×n 泵 +P 风机 ×n 风机 ×0.37

[0018] Among them, P 电 is the electricity consumption cost, P 泵 is the power of the slurry circulation pump, n 泵 is the number of slurry circulation pumps in operation, P 风机 is the power of the oxidation fan, n 风机 is the number of oxidation fans in operation. The power of the slurry circulation pump and oxidation fan is the preset value. The number of units in operation is related to the flue gas volume and the inlet sulfur dioxide concentration. The number of slurry circulation pumps in operation increases with the increase of flue gas volume and inlet sulfur dioxide concentration. The total amount of sulfur dioxide removed is expressed as:

[0019]

[0020]

[0021]

[0022] in, is the total amount of sulfur dioxide in the flue gas at the inlet, and f2 is the relationship between the number of slurry circulation pumps in operation and the total amount of sulfur dioxide at the inlet.

[0023] As a preferred solution of the optimal calculation and control method for the economic efficiency of the desulfurization system described in the present invention, the calculation of water consumption and environmental protection tax costs includes that in the wet desulfurization process, water is used for the circulation of slurry and the generation of gypsum. The water consumption is related to the consumption of limestone and the desulfurization efficiency. When the desulfurization efficiency is improved and the limestone consumption increases, the water consumption cost increases. The fluctuation of the actual water consumption cost reflects the change of the system operation state. The environmental protection tax cost is calculated according to the emission concentration of sulfur dioxide and the unit price of the environmental protection tax. When the actual emission concentration is lower than the standard at different stages, the environmental protection tax will be charged according to different gradients. The water consumption and environmental protection tax costs are expressed as follows:

[0024]

[0025]

[0026] Among them, P 水 is the water consumption cost, P税 is the environmental protection tax cost, k is the unit price of environmental protection tax. When the actual emission concentration is 50% lower than the standard, it will be charged at 75%, and when the actual emission concentration is 30% lower than the standard, it will be charged at 50%.

[0027] As a preferred solution of the method for calculating and controlling the economic efficiency of the desulfurization system described in the present invention, the total cost calculation includes multiple factors such as limestone, electricity consumption, water consumption and environmental protection tax. Each cost shows different changing trends with the change of desulfurization efficiency and outlet sulfur dioxide concentration. The total cost shows different extreme value characteristics with the change of outlet sulfur dioxide concentration. When the outlet sulfur dioxide concentration decreases, the environmental protection tax cost decreases, and the limestone cost, electricity consumption cost and water consumption cost increase significantly. The most economical operating point of the desulfurization system appears within a certain range of outlet sulfur dioxide concentration. Within the range, the increase of each cost is balanced, and the minimum value of the total cost is obtained. The total cost is expressed as:

[0028]

[0029]

[0030] When the flue gas volume is constant and under the condition of inlet sulfur dioxide, the total cost is related to the outlet sulfur dioxide concentration, and the outlet sulfur dioxide concentration has opposite effects on different sub-item costs.

[0031] As a preferred solution of the desulfurization system economic optimal calculation control method described in the present invention, wherein: the method of obtaining the minimum value of the most economical total cost function of the desulfurization system includes determining the optimal outlet sulfur dioxide concentration by solving the minimum value of the function, and using it as the target value of system control. In actual control, the desulfurization system uses a distributed control system for real-time adjustment to control the operating parameters of the slurry circulation pump and the oxidation fan equipment to keep the outlet sulfur dioxide concentration within a predetermined range. The minimum value of the function is expressed as:

[0032]

[0033] Among them, P min is the minimum value of the total cost.

[0034] Another object of the present invention is to provide a desulfurization system economic optimal calculation and control system, which can establish the relationship between the number of slurry circulation pumps put into operation, the flue gas volume and the inlet sulfur dioxide concentration through a cost calculation module, calculate the water consumption and environmental protection tax costs, and solve the current problem of inaccurate control of electricity consumption and water consumption.

[0035] As a preferred solution of the optimal calculation and control system for the economic efficiency of the desulfurization system described in the present invention, it includes: a limestone cost module, a cost calculation module, and a minimum total cost module; the limestone cost module calculates the calcium-sulfur ratio and the desulfurization efficiency under the conditions of stable load and stable inlet, and optimizes the limestone cost; the cost calculation module is used to establish the relationship between the number of slurry circulation pumps put into operation and the flue gas volume and inlet sulfur dioxide concentration, and calculate the water consumption and environmental protection tax cost; the minimum total cost module is used to calculate the total cost and obtain the minimum value of the most economical operating total cost function of the desulfurization system.

[0036] A computer device includes a memory and a processor, wherein the memory stores a computer program, and is characterized in that the processor executes the computer program to implement a step of a method for calculating and controlling the economic optimality of a desulfurization system.

[0037] A computer-readable storage medium stores a computer program thereon, characterized in that when the computer program is executed by a processor, the steps of a method for calculating and controlling the economic optimality of a desulfurization system are implemented.

[0038] Beneficial effects of the present invention: The optimal calculation and control method for the economic efficiency of the desulfurization system provided by the present invention optimizes the consumption of limestone by calculating the calcium-sulfur ratio and the desulfurization efficiency, thereby improving the operating economy and long-term effectiveness of the desulfurization system, and establishing the relationship between the number of slurry circulation pumps in operation and the flue gas volume and the inlet sulfur dioxide concentration, thereby reducing the maintenance frequency and expense expenditure, and reducing the overall operating cost through accurate calculation of water consumption and environmental protection tax. The control system is used to improve the stability and operating efficiency of the system according to the optimal outlet sulfur dioxide concentration obtained by solving the optimal solution. The present invention achieves better results in terms of operating economy, operating cost and operating efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0040] Figure 1 An overall flow chart of a method for calculating and controlling the economic optimality of a desulfurization system provided in the first embodiment of the present invention.

[0041] Figure 2 This is an overall module diagram of a desulfurization system economic optimal calculation and control system provided in the third embodiment of the present invention. DETAILED DESCRIPTION

[0042] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0043] Example 1

[0044] Reference Figure 1 , which is an embodiment of the present invention, provides a method for calculating and controlling the economic optimality of a desulfurization system, comprising:

[0045] S1: Under the conditions of stable load and stable inlet, calculate the calcium-sulfur ratio and desulfurization efficiency to optimize the limestone cost.

[0046] Furthermore, optimizing limestone cost includes calculating limestone cost based on the sulfur dioxide concentration in the flue gas and the calcium-sulfur ratio of the desulfurization system.

[0047] It should be noted that the limestone consumption is positively correlated with the inlet sulfur dioxide concentration. The higher the inlet sulfur dioxide concentration, the greater the demand for limestone. The lower the outlet sulfur dioxide concentration, the more limestone is consumed. When the outlet sulfur dioxide concentration decreases, the calcium-sulfur ratio increases, and the limestone consumption increases. The desulfurization efficiency and outlet sulfur dioxide concentration are controlled to optimize the limestone cost. The limestone cost calculation is expressed as:

[0048]

[0049]

[0050] in, For limestone costs, is the limestone consumption, V RG is the flue gas volume flow rate, is the inlet sulfur dioxide concentration in the flue gas, is the sulfur dioxide emission concentration in flue gas, is the molar mass of calcium carbonate, is the molar mass of sulfur dioxide, F R is the purity of limestone, S t The limestone cost is proportional to the flue gas volume and the calcium-sulfur ratio, proportional to the inlet sulfur dioxide concentration, and inversely proportional to the outlet sulfur dioxide concentration.

[0051] Furthermore, the calculation of calcium-sulfur ratio and desulfurization efficiency includes the ratio of calcium carbonate consumed to sulfur dioxide removed.

[0052] It should be noted that, under the condition of determining the pH value of the desulfurization tower and the quality of limestone, the desulfurization efficiency increases with the increase of the desulfurization efficiency. Through the unit variable outlet sulfur dioxide test, under the conditions of stable load and stable inlet, the desulfurization efficiency is changed, the actual limestone consumption is counted, the gypsum sample is obtained, and the DCS data is saved during the test. The calcium-sulfur ratio and desulfurization efficiency are calculated. The relationship between the calcium-sulfur ratio and the desulfurization efficiency is expressed as:

[0053]

[0054] S t =f(η)

[0055]

[0056] Among them, η is the desulfurization efficiency, which represents the removal rate of sulfur dioxide in the system, and f1 is the limestone consumption function.

[0057] S2: Establish the relationship between the number of slurry circulation pumps in operation, flue gas volume and inlet sulfur dioxide concentration, and calculate water consumption and environmental protection tax costs.

[0058] Furthermore, the relationship between the number of slurry circulation pumps put into operation and the flue gas volume and inlet sulfur dioxide concentration is established, including the calculation of electricity consumption costs.

[0059] It should be noted that the electricity consumption cost is affected by the operating status of the slurry circulation pump and the oxidation fan, which can be expressed as:

[0060] P 电 =P 泵 ×n 泵 +P 风机 ×n 风机 ×0.37

[0061] Among them, P 电 is the electricity consumption cost, P 泵 is the power of the slurry circulation pump, n 泵 is the number of slurry circulation pumps in operation, P 风机 is the power of the oxidation fan, n 风机 is the number of oxidation fans in operation. The power of the slurry circulation pump and oxidation fan is the preset value. The number of units in operation is related to the flue gas volume and the inlet sulfur dioxide concentration. The number of slurry circulation pumps in operation increases with the increase of flue gas volume and inlet sulfur dioxide concentration. The total amount of sulfur dioxide removed is expressed as:

[0062]

[0063]

[0064]

[0065] in, is the total amount of sulfur dioxide in the flue gas at the inlet, and f2 is the relationship between the number of slurry circulation pumps in operation and the total amount of sulfur dioxide at the inlet.

[0066] Furthermore, the calculation of water consumption and environmental tax costs includes the wet flue gas desulfurization process.

[0067] It should be noted that water is used for the circulation of slurry and the production of gypsum. Water consumption is related to limestone consumption and desulfurization efficiency. When desulfurization efficiency is improved and limestone consumption increases, water consumption costs rise. The fluctuation of actual water consumption costs reflects the changes in the operating status of the system. The environmental protection tax cost is calculated based on the emission concentration of sulfur dioxide and the unit price of environmental protection tax. When the actual emission concentration is lower than the standard at different stages, environmental protection taxes will be charged according to different gradients. Water consumption and environmental protection tax costs are expressed as:

[0068]

[0069]

[0070] Among them, P 水 is the water consumption cost, P 税 is the environmental protection tax cost, k is the unit price of environmental protection tax. When the actual emission concentration is 50% lower than the standard, it will be charged at 75%, and when the actual emission concentration is 30% lower than the standard, it will be charged at 50%.

[0071] S3: Calculate the total cost and find the minimum value of the most economical total cost function for the desulfurization system.

[0072] Furthermore, the total cost calculation includes combining limestone, electricity consumption, water consumption and environmental taxes.

[0073] It should be noted that various costs show different trends with changes in desulfurization efficiency and outlet sulfur dioxide concentration, and the total cost shows different extreme value characteristics with changes in outlet sulfur dioxide concentration. When the outlet sulfur dioxide concentration decreases, the environmental protection tax cost decreases, and the limestone cost, electricity consumption cost and water consumption cost increase significantly. The most economical operating point of the desulfurization system appears within a certain range of outlet sulfur dioxide concentration. Within the range, the increase of various costs remains balanced, and the lowest value of the total cost will be obtained. The total cost is expressed as:

[0074]

[0075]

[0076] When the flue gas volume is constant and under the condition of inlet sulfur dioxide, the total cost is related to the outlet sulfur dioxide concentration, and the outlet sulfur dioxide concentration has opposite effects on different sub-item costs.

[0077] Furthermore, finding the minimum value of the most economical operating total cost function of the desulfurization system includes finding the minimum value of the function.

[0078] It should be noted that the optimal outlet sulfur dioxide concentration is determined and used as the target value of system control. In actual control, the desulfurization system uses a distributed control system for real-time adjustment to control the operating parameters of the slurry circulation pump and oxidation fan equipment to keep the outlet sulfur dioxide concentration within a predetermined range. The minimum value of the solution function is expressed as:

[0079]

[0080] Among them, P min is the minimum value of the total cost.

[0081] Example 2

[0082] One embodiment of the present invention provides a method for calculating and controlling the economic optimality of a desulfurization system. In order to verify the beneficial effects of the present invention, scientific demonstration is carried out through economic benefit calculation and simulation experiments.

[0083] Taking a 1000MW unit as an example, firstly, under the conditions of stable load and stable inlet, by changing the outlet SO2, the calcium-sulfur ratio and desulfurization efficiency are calculated. Through experiments, the relationship between the number of slurry circulation pumps put into operation, the flue gas volume and the inlet SO2 concentration is established.

[0084] As shown in Table 1-Table 2, when the unit flue gas volume is 1000000, the optimal value of the outlet SO2 concentration is different under different inlet SO2 concentrations. When the inlet SO2 concentration is 1000, the outlet SO2 concentration is controlled between 17.5 and 24.5, and the total cost is the lowest. If the outlet SO2 concentration is controlled between 0 and 17.5, the environmental protection tax is the lowest, but due to the high efficiency, the limestone cost and water consumption cost increase. If the outlet SO2 concentration is controlled between 17.5 and 24.5, the limestone and water consumption costs are the lowest, but the environmental protection tax is The highest is when the inlet SO2 concentration is 1500, the outlet SO2 concentration is controlled between 24.5 and 35, and the total cost is the lowest. If the outlet SO2 concentration is controlled below 24.5, the environmental protection tax is reduced, but due to the higher efficiency, the limestone cost and water consumption cost increase. When the inlet SO2 concentration is 2000, the outlet SO2 concentration is controlled between 24.5 and 35, and the total cost is the lowest. If the outlet SO2 concentration is controlled below 24.5, the environmental protection tax is reduced, but due to the higher efficiency, the limestone cost and water consumption cost increase.

[0085] Table 1 Relationship between the number of slurry circulation pumps in operation, flue gas volume and inlet SO2 concentration

[0086] Total SO2 removal (kg / h) Number of slurry circulation pumps put into operation 0～1000 1 1000～2000 2 2000～3000 2 3000～4000 3 4000～5000 4 5000～6000 4

[0087] Table 2 Total cost calculation results

[0088]

[0089] Example 3

[0090] Reference Figure 2 , which is an embodiment of the present invention, provides a desulfurization system economic optimal calculation and control system, including: a limestone cost module, a cost calculation module, and a minimum total cost module.

[0091] The limestone cost module calculates the calcium-sulfur ratio and desulfurization efficiency under stable load and inlet conditions to optimize the limestone cost; the cost calculation module is used to establish the relationship between the number of slurry circulation pumps in operation, the flue gas volume and the inlet sulfur dioxide concentration, and calculate the water consumption and environmental protection tax costs; the minimum total cost module is used to calculate the total cost and find the minimum value of the most economical total cost function for the desulfurization system.

[0092] If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0093] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in conjunction with such instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in conjunction with such instruction execution systems, devices or apparatuses.

[0094] More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be a paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering, or processing in another suitable manner as necessary, and then stored in a computer memory.

[0095] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc. It should be noted that the above embodiments are only used to illustrate the technical solution of the present invention and are not limited. Although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

[0096] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for calculating and controlling the economic efficiency of a desulfurization system, characterized in that: include: Under the conditions of stable load and stable inlet, calculate the calcium-sulfur ratio and desulfurization efficiency to optimize the limestone cost; Establish the relationship between the number of slurry circulation pumps in operation, flue gas volume and inlet sulfur dioxide concentration, and calculate water consumption and environmental protection tax costs; Calculate the total cost and find the minimum value of the most economical total cost function for the desulfurization system.

2. The method for calculating and controlling the economic efficiency of a desulfurization system according to claim 1, characterized in that: The optimization of limestone cost includes calculating the limestone cost based on the sulfur dioxide concentration in the flue gas and the calcium-sulfur ratio of the desulfurization system. The limestone consumption is positively correlated with the inlet sulfur dioxide concentration. The higher the inlet sulfur dioxide concentration, the greater the demand for limestone. The lower the outlet sulfur dioxide concentration, the more limestone is consumed. When the outlet sulfur dioxide concentration decreases, the calcium-sulfur ratio increases, and the limestone consumption increases. The desulfurization efficiency and the outlet sulfur dioxide concentration are controlled to optimize the limestone cost. The limestone cost calculation is expressed as: in, For limestone costs, is the limestone consumption, V RG is the flue gas volume flow rate, is the inlet sulfur dioxide concentration in the flue gas, is the sulfur dioxide emission concentration in flue gas, is the molar mass of calcium carbonate, is the molar mass of sulfur dioxide, F R is the purity of limestone, S t The limestone cost is proportional to the flue gas volume and the calcium-sulfur ratio, proportional to the inlet sulfur dioxide concentration, and inversely proportional to the outlet sulfur dioxide concentration.

3. The method for calculating and controlling the economic efficiency of a desulfurization system according to claim 2, characterized in that: The calculation of calcium-sulfur ratio and desulfurization efficiency includes the ratio of consumed calcium carbonate to removed sulfur dioxide. When the pH value of the desulfurization tower and the quality of limestone are determined, the ratio increases with the increase of desulfurization efficiency. Through the unit variable outlet sulfur dioxide test, under the condition of stable load and stable inlet, the desulfurization efficiency is changed, the actual limestone consumption is counted, the gypsum sample is obtained, and the DCS data is saved during the test. The calcium-sulfur ratio and desulfurization efficiency are calculated. The relationship between the calcium-sulfur ratio and the desulfurization efficiency is expressed as follows: S t =f(n) Among them, η is the desulfurization efficiency, which represents the removal rate of sulfur dioxide in the system, and f1 is the limestone consumption function.

4. The method for calculating and controlling the economic optimum of a desulfurization system according to claim 3, characterized in that: The relationship between the number of slurry circulation pumps put into operation, the flue gas volume and the inlet sulfur dioxide concentration includes calculating the power consumption cost. The power consumption cost is affected by the operating status of the slurry circulation pump and the oxidation fan, and is expressed as: P 电 =(P 泵 ×n 泵 +P 风机 ×n 风机 )×0.37 Among them, P 电 is the electricity consumption cost, P 泵 is the power of the slurry circulation pump, n 泵 is the number of slurry circulation pumps in operation, P 风机 is the power of the oxidation fan, n 风机 is the number of oxidation fans in operation. The power of the slurry circulation pump and oxidation fan is the preset value. The number of units in operation is related to the flue gas volume and the inlet sulfur dioxide concentration. The number of slurry circulation pumps in operation increases with the increase of flue gas volume and inlet sulfur dioxide concentration. The total amount of sulfur dioxide removed is expressed as: in, is the total amount of sulfur dioxide in the flue gas at the inlet, and f2 is the relationship between the number of slurry circulation pumps in operation and the total amount of sulfur dioxide at the inlet.

5. The method for calculating and controlling the economic efficiency of a desulfurization system according to claim 4, characterized in that: The calculation of water consumption and environmental protection tax costs includes the use of water for slurry circulation and gypsum production during wet flue gas desulfurization. Water consumption is related to limestone consumption and desulfurization efficiency. When desulfurization efficiency is improved and limestone consumption increases, water consumption costs rise. The fluctuation of actual water consumption costs reflects the changes in the operating status of the system. The environmental protection tax cost is calculated based on the emission concentration of sulfur dioxide and the unit price of the environmental protection tax. When the actual emission concentration is lower than the standard at different stages, the environmental protection tax will be charged according to different gradients. The water consumption and environmental protection tax costs are expressed as follows: Among them, p 水 is the water consumption cost, p 税 is the environmental protection tax cost, k is the unit price of environmental protection tax. When the actual emission concentration is 50% lower than the standard, it will be charged at 75%, and when the actual emission concentration is 30% lower than the standard, it will be charged at 50%.

6. The method for calculating and controlling the economic optimum of a desulfurization system according to claim 5, characterized in that: The calculation of the total cost includes combining limestone, electricity consumption, water consumption and environmental protection tax. Each cost shows different trends with the change of desulfurization efficiency and outlet sulfur dioxide concentration. The total cost shows different extreme value characteristics with the change of outlet sulfur dioxide concentration. When the outlet sulfur dioxide concentration decreases, the environmental protection tax cost decreases, and the limestone cost, electricity consumption cost and water consumption cost increase significantly. The most economical operating point of the desulfurization system appears within a certain range of outlet sulfur dioxide concentration. Within the range, the increase of each cost remains balanced, and the minimum value of the total cost will be obtained. The total cost is expressed as: When the flue gas volume is constant and under the condition of inlet sulfur dioxide, the total cost is related to the outlet sulfur dioxide concentration, and the outlet sulfur dioxide concentration has opposite effects on different sub-item costs.

7. The method for calculating and controlling the economic optimum of a desulfurization system according to claim 6, characterized in that: The method of obtaining the minimum value of the most economical total cost function of the desulfurization system includes determining the optimal outlet sulfur dioxide concentration by solving the minimum value of the function, and using it as the target value of system control. In actual control, the desulfurization system uses a distributed control system for real-time adjustment to control the operating parameters of the slurry circulation pump and the oxidation fan equipment to keep the outlet sulfur dioxide concentration within a predetermined range. The minimum value of the function is expressed as: Among them, P min is the minimum value of the total cost.

8. A system using the desulfurization system economic optimization calculation and control method as claimed in any one of claims 1 to 7, characterized in that: Includes limestone cost module, cost calculation module, and minimum total cost module; The limestone cost module calculates the calcium-sulfur ratio and desulfurization efficiency under the conditions of stable load and stable inlet, and optimizes the limestone cost; The cost calculation module is used to establish the relationship between the number of slurry circulation pumps put into operation, the flue gas volume and the inlet sulfur dioxide concentration, and calculate the water consumption and environmental protection tax costs; The minimum total cost module is used to calculate the total cost and find the minimum value of the most economical operation total cost function of the desulfurization system.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the desulfurization system economic optimization calculation control method described in any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the desulfurization system economic optimization calculation control method described in any one of claims 1 to 7 are implemented.

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