Wet desulphurization intelligent gypsum oxidation and dehydration comprehensive process optimization method

Abstract

The invention provides an intelligent gypsum oxidation and dehydration comprehensive process optimization method for wet desulphurization. The method comprises the following steps: installing a sulfite and gypsum moisture content online detector in a desulphurization system to construct an intelligent sensing system; an oxidation air utilization rate model is established, and the oxidation air volume is dynamically calculated and adjusted in a variable frequency mode according to the SO2 removal amount; establishing a dehydration operation control model, and dynamically adjusting parameters such as vacuum degree and filter cake thickness; constructing an oxidation-dehydration coupling model to realize system collaborative optimization; and finally, advanced process control is implemented through integration of the intelligent environment-friendly island digital intelligent platform. According to the method, the remarkable energy-saving effect that the electricity-saving rate of the oxidation fan exceeds 20% and the electricity-saving rate of the vacuum pump reaches 35% is achieved, the water content of gypsum is stably controlled to be 9.5% or below, the problems that a traditional process is high in energy consumption, unstable in operation and lack of collaborative optimization are effectively solved, and the method has both environmental protection and economic benefits.

Description

Technical Field

[0001] This invention relates to the fields of environmental protection and industrial automation technology, and in particular to a comprehensive process optimization method for intelligent gypsum oxidation and dehydration in wet desulfurization. Background Technology

[0002] Wet desulfurization systems are widely used in thermal power plants, with core processes including gypsum oxidation and dehydration. In existing technologies, oxidation fans typically operate at a fixed frequency, unable to dynamically adjust airflow according to actual SO2 load, resulting in persistently high energy consumption. For example, a 500kW oxidation fan can have an excess airflow rate exceeding 40% under low-load conditions, causing significant energy waste.

[0003] The dewatering system lacks real-time monitoring of gypsum moisture content, making it impossible to dynamically adjust dewatering parameters (such as vacuum level, filter cake thickness, belt speed, etc.) based on gypsum quality. Existing systems rely on manual, periodic sampling and testing, resulting in delayed feedback and large fluctuations in gypsum moisture content (typically between 10% and 15%), unstable quality, and high energy consumption during dewatering. A single 280kW vacuum pump often operates at its rated power year-round, lacking any means of adjustment.

[0004] More seriously, there is a lack of synergistic optimization mechanisms between the oxidation and dehydration systems. Insufficient oxidation leads to excessive calcium sulfite, resulting in fine, viscous gypsum crystals, which in turn affects dehydration efficiency, creating a vicious cycle. Currently, the system lacks a mechanism to counteract sulfite (SO32-) ions. 2- ), chloride ions (Cl) - Online monitoring of key indicators such as oxidation and dehydration systems makes precise control and energy-saving optimization difficult. Therefore, there is an urgent need for a comprehensive process method that can achieve intelligent synergy, precise control, and energy-saving optimization of oxidation and dehydration systems to improve the overall operating efficiency and economy of the system. Summary of the Invention

[0005] The purpose of this invention is to provide a comprehensive process optimization method for intelligent gypsum oxidation and dehydration in wet desulfurization, which solves the problems of high energy consumption, unstable operation, and lack of synergistic optimization in the existing oxidation and dehydration systems.

[0006] According to one objective of the present invention, the present invention provides a comprehensive process optimization method for intelligent gypsum oxidation and dehydration in wet desulfurization, comprising the following steps: Step (1) Construction of intelligent sensing system: Install an online sulfite analyzer and an online gypsum moisture content detector in the desulfurization system to monitor the sulfite concentration in the absorber slurry and the moisture content of the dehydrated gypsum in real time; Step (2) Intelligent optimization of oxidation system: Establish an oxidation air utilization model, and dynamically calculate the required oxidation air volume based on SO2 removal, oxidation fan operating parameters and sulfite concentration; Step (3) Intelligent optimization of the dehydration system: Establish a dehydration operation control model, analyze the correlation between moisture content and dehydration system operating parameters, and dynamically adjust the dehydration system operating parameters; Step (4) System Co-optimization: Establish an oxidation-dehydration coupling model to achieve linkage adjustment of oxidation air volume and dehydration parameters; Step (5) Construction of intelligent control platform: Build a smart environmental protection island digital platform to integrate real-time data acquisition, model calculation and advanced process control functions.

[0007] Further, in step (1), the online sulfite analyzer has a measurement range of 0-500 mg / L and an accuracy of ±5%; the online gypsum moisture content detector has a measurement range of 0-20% and an accuracy of ±0.3%, and is installed 300-450 mm in front of the discharge port of the vacuum belt dewatering machine.

[0008] Further, in step (2), the calculation formula of the oxidation wind utilization model is: QO2= K×QSO2 / ρ, where QO2 is the theoretical oxygen demand, QSO2 is the SO2 removal amount, ρ is the oxygen density, and K is a coefficient related to the stoichiometric ratio of the chemical reaction.

[0009] Furthermore, the coefficient K is set to 0.5, and the oxygen density ρ is set to 1.43 kg / Nm³. 3 Based on the theoretical oxygen demand QO2, the theoretical air demand QaN = QO2 / 21% and the actual air demand QaV = QaN × TV / 273.15 are further calculated, where TV is the ambient temperature at the inlet of the oxidation fan, in K.

[0010] Furthermore, based on the actual required air volume QaV, the oxidation air volume is controlled by frequency conversion adjustment of the oxidation blower, and the sulfite concentration in the absorber slurry is stably controlled below 200 mg / L.

[0011] Furthermore, in step (3), the operating parameters of the dewatering system include one or more of the following: vacuum degree, filter cake thickness, belt speed, and slurry density. The goal of dynamically adjusting the operating parameters of the dewatering system is to control the moisture content of gypsum to below 10%.

[0012] Furthermore, in step (4), the oxidation-dehydration coupling model establishes a correlation by analyzing the influence of oxidation efficiency on gypsum crystallization and dehydration performance. The correlation is as follows: when the sulfite concentration exceeds 200 mg / L, the dehydration energy consumption increases by 15%-20%, and the gypsum moisture content rises to 12%-15%.

[0013] Furthermore, in step (4), the goal of the linkage adjustment is to minimize the total system energy consumption and optimize the gypsum quality, wherein the total system energy consumption E total =E ox +E de +E penalty ; where E ox For the energy consumption of the oxidation system, E de For the energy consumption of the dehydration system, E penalty This refers to the penalty costs incurred due to substandard quality.

[0014] Furthermore, in step (5), the advanced process control adopts a multivariable model predictive control algorithm to achieve multivariable coordinated control of pH value, slurry supply, oxidation fan frequency, and vacuum pump frequency.

[0015] Furthermore, after implementing the method, the energy saving rate of the oxidation blower exceeds 20%, the energy saving rate of the vacuum pump reaches 35%, and the moisture content of the gypsum is stably controlled below 9.5%.

[0016] This invention achieves precise and coordinated control of the gypsum oxidation and dehydration processes by constructing an intelligent sensing system and an optimized model. After application, the oxidation blower saves over 20% of electricity, and the vacuum pump saves 35%, significantly reducing energy consumption. The gypsum moisture content is stably controlled below 9.5%, fluctuating between 10% and 15%, resulting in significantly improved quality that meets commercial standards. System stability is enhanced, reducing operator intervention frequency by 70%, while also lowering wastewater discharge and reagent consumption, achieving a win-win situation for both environmental protection and economic benefits, and comprehensively improving the automation and intelligence level of the desulfurization system. Attached Figure Description

[0017] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a flowchart illustrating the early warning method according to an embodiment of the present invention. Detailed Implementation

[0019] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0021] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. Furthermore, the terms "installed," "connected," and "linked" should be interpreted broadly; for example, they may refer to a fixed connection, a detachable connection, or an integral connection; they may refer to a mechanical connection or an electrical connection; they may refer to a direct connection or an indirect connection through an intermediate medium; and they may refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0022] Example 1 like Figure 1 As shown, A comprehensive process optimization method for wet desulfurization intelligent gypsum oxidation and dehydration includes the following steps: (1) Construction of intelligent sensing system: Install an online sulfite analyzer and an online gypsum moisture content detector in the desulfurization system to monitor the sulfite concentration in the absorber slurry and the moisture content of the dehydrated gypsum in real time; (2) Intelligent optimization of oxidation system: Establish an oxidation air utilization model, and dynamically calculate the required oxidation air volume based on SO2 removal, oxidation fan operating parameters and sulfite concentration; (3) Intelligent optimization of dehydration system: Establish a dehydration operation control model, analyze the correlation between moisture content and dehydration system operating parameters, and dynamically adjust the dehydration system operating parameters; (4) System collaborative optimization: Establish an oxidation-dehydration coupling model to realize the linkage adjustment of oxidation air volume and dehydration parameters; (5) Construction of intelligent control platform: Build a smart environmental protection island digital platform to integrate real-time data acquisition, model calculation and advanced process control functions.

[0023] Specifically, in step (1), the online sulfite analyzer has a measurement range of 0-500 mg / L and an accuracy of ±5%.

[0024] In step (1), the measurement range of the online gypsum moisture content detector is 0-20%, and the accuracy is ±0.3%; the online gypsum moisture content detector is installed in front of the discharge port of the vacuum belt dewatering machine; the installation position of the online gypsum moisture content detector is 300-450mm away from the discharge port.

[0025] Specifically, in step (2), the calculation formula for the oxidation wind utilization rate model is as follows: QO2 = K × QSO2 / ρ, where QO2 is the theoretical oxygen demand, QSO2 is the SO2 removal rate, ρ is the oxygen density, and K is a coefficient related to the stoichiometric ratio of the chemical reaction. Specifically, the coefficient K is set to 0.5, and the oxygen density ρ is set to 1.43 kg / Nm³. 3 .

[0026] Specifically, based on the theoretical oxygen demand QO2, the theoretical air volume demand QaN is further calculated as QO2 / 21%. Based on the theoretical air volume demand QaN, the actual air volume demand QaV is further calculated as QaN×TV / 273.15, where TV is the ambient temperature at the inlet of the oxidation fan in K. According to the actual air volume demand QaV, the oxidation air volume is controlled by frequency conversion adjustment of the oxidation fan.

[0027] Specifically, in step (2), the concentration of sulfite in the slurry of the absorption tower is stably controlled below 200 mg / L by controlling the oxidation air volume.

[0028] Specifically, in step (3), the operating parameters of the dewatering system include one or more of the following: vacuum degree, filter cake thickness, belt speed, and slurry density. The goal of dynamically adjusting the operating parameters of the dewatering system is to control the gypsum moisture content below 10%. Step (3) also includes optimizing the distribution of the underflow and overflow of the hydrocyclone to improve the solid phase recovery rate.

[0029] Specifically, in step (4), the oxidation-dehydration coupling model establishes a correlation by analyzing the influence of oxidation efficiency on the crystallization and dehydration performance of gypsum; the correlation is as follows: when the sulfite concentration exceeds 200 mg / L, the dehydration energy consumption increases by 15%-20%, and the gypsum moisture content rises to 12%-15%. In step (4), the goal of the linkage adjustment is to minimize the total energy consumption of the system and optimize the gypsum quality.

[0030] The total energy consumption of the system E total = E ox + E de + Epenalty E oxFor the energy consumption of the oxidation system, E de For the energy consumption of the dehydration system, E penalty This refers to the penalty costs incurred due to substandard quality.

[0031] Specifically, in step (5), the advanced process control adopts a multivariate model predictive control algorithm to achieve multivariate coordinated control of pH value, slurry supply, oxidation fan frequency and vacuum pump frequency; the smart environmental protection island digital platform in step (5) is equipped with an oxidation air demand dynamic optimization model, a dewatering process intelligent control model and an oxidation-dewatering co-optimizer.

[0032] After adopting the method described in this embodiment, the power saving rate of the oxidation blower exceeds 20%, the power saving rate of the vacuum pump reaches 35%, and the moisture content of gypsum is stably controlled below 9.5%.

[0033] The method described in this embodiment is applicable to the intelligent transformation and optimized operation of flue gas desulfurization systems in coal-fired power plants.

[0034] Example 2 This embodiment presents a comprehensive process optimization method for intelligent gypsum oxidation and dehydration in wet desulfurization, using a typical limestone-gypsum wet desulfurization system in a coal-fired power plant as the application example.

[0035] The system is equipped with an absorption tower, two 500kW centrifugal oxidation fans (one for use and one for standby), a vacuum belt dewatering machine, and corresponding auxiliary equipment.

[0036] First, the overall system architecture is constructed. This architecture is divided into three layers from top to bottom: the intelligent application and optimization layer, the control and execution layer, and the intelligent sensing and device layer.

[0037] Regarding the installation of intelligent sensing devices and data access: An online sulfite analyzer with a measurement range of 0-500 mg / L and an accuracy of ±5% was installed on the outlet pipeline of the slurry circulation pump in the absorption tower. An online gypsum moisture content meter is installed approximately 300-450mm in front of the material discharge port of the vacuum belt dewatering machine. Its measurement range is 0-20%, and its accuracy is ±0.3%. Install frequency converters on the oxidation blower and vacuum pump, and connect the control signals to the DCS / APC system. Regarding the development and deployment of software platforms and intelligent models: Develop and deploy the following core intelligent models on the digital intelligence software platform: The dynamic optimization model for oxidation air demand uses the following calculation formula: QO2 = 0.5 × QSO2 / ρ; QaN = QO2 / 0.21; QaV = QaN × TV / 273.15 Fs = ks×QaV / QaF; Where: QO2 is the theoretical oxygen demand (kg / h), QSO2 is the SO2 removal rate (kg / h), and ρ is the oxygen density (taken as 1.43 kg / Nm³). 3 QaN is the theoretical air volume required (Nm³). 3 / h), QaV is the actual required air volume (m³ / h). 3 / h), TV is the ambient temperature at the inlet of the oxidation fan (K), Fs is the frequency setting value of the oxidation fan (Hz), QaF is the rated air volume of the oxidation fan (m³ / h). 3 / h), where ks is the comprehensive correction coefficient obtained through training with historical data. A smart control model for the dehydration process is established, creating a mathematical relationship between the gypsum moisture content ω and the manipulated variables: ω = f(Pv, Vb, Hf, ρs); where: Pv is the vacuum degree, Vb is the belt speed, Hf is the filter cake thickness, and ρs is the slurry density.

[0038] The oxidation-dehydration co-optimizer uses the minimum total system energy consumption as its objective function. min E total =E ox +E de +E penalty ; where: E ox For the energy consumption of the oxidation system, E de Energy consumption of the dehydration system Epenalty This refers to the penalty costs incurred due to substandard quality.

[0039] Regarding the implementation and commissioning of the control loop: Configure a multivariable model predictive control algorithm in the APC controller to receive optimized setpoints from the digital intelligence platform; achieve seamless switching and safety interlocking between APC control and the original manual control mode through DCS system configuration.

[0040] After implementing the method of this invention, the system achieved significant results: the average operating power of the oxidation blower was reduced from 500kW to 380kW, with an energy saving rate of 24% and an annual energy saving of approximately 1 million kWh; the average operating power of the vacuum pump was reduced from 280kW to 185kW, with an energy saving rate of 35% and an annual energy saving of approximately 200,000 kWh per unit; the moisture content of gypsum products was stably controlled below 9.5%; and the frequency of manual intervention by operators was reduced by 70%.

[0041] This invention offers significant energy savings and reduced consumption. The oxidation blower can supply air on demand, achieving an energy saving rate of over 20%, with a single 500kW blower saving up to 1 million kWh per year. The dehydration system, through optimized vacuum pump operation, achieves an energy saving rate of 35%, with a single 280kW vacuum pump saving approximately 200,000 kWh per year. This invention also improves gypsum quality. Through real-time monitoring and control, the gypsum moisture content, which fluctuates between 10% and 15%, is stably controlled below 9.5%, achieving commercial-grade gypsum quality.

[0042] This invention enhances system stability, avoiding poor gypsum crystallization and dehydration difficulties caused by insufficient oxidation, reducing system fluctuations and manual intervention, and decreasing the frequency of operator manual intervention by 70%. This invention achieves a win-win situation for environmental protection and economy, reducing wastewater discharge and reagent consumption, and is expected to save approximately 280,000 yuan in wastewater treatment costs annually. This invention improves the level of intelligence, realizing closed-loop intelligent control from perception, analysis, decision-making to execution, and promoting the transformation of environmental protection islands towards intelligence and low carbon emissions.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A comprehensive process optimization method for wet desulfurization intelligent gypsum oxidation and dehydration, characterized in that, Includes the following steps: Step (1) Construction of intelligent sensing system: Install an online sulfite analyzer and an online gypsum moisture content detector in the desulfurization system to monitor the sulfite concentration in the absorber slurry and the moisture content of the dehydrated gypsum in real time; Step (2) Intelligent optimization of oxidation system: Establish an oxidation air utilization model, and dynamically calculate the required oxidation air volume based on SO2 removal, oxidation fan operating parameters and sulfite concentration; Step (3) Intelligent optimization of the dehydration system: Establish a dehydration operation control model, analyze the correlation between moisture content and dehydration system operating parameters, and dynamically adjust the dehydration system operating parameters; Step (4) System Co-optimization: Establish an oxidation-dehydration coupling model to achieve linkage adjustment of oxidation air volume and dehydration parameters; Step (5) Construction of intelligent control platform: Build a smart environmental protection island digital platform to integrate real-time data acquisition, model calculation and advanced process control functions.

2. The integrated process optimization method for wet desulfurization intelligent gypsum oxidation and dehydration according to claim 1, characterized in that, In step (1), the online sulfite analyzer has a measurement range of 0-500 mg / L and an accuracy of ±5%; the online gypsum moisture content detector has a measurement range of 0-20% and an accuracy of ±0.3%, and is installed 300-450 mm in front of the discharge port of the vacuum belt dewatering machine.

3. The integrated process optimization method for wet desulfurization intelligent gypsum oxidation and dehydration according to claim 1, characterized in that, In step (2), the calculation formula of the oxidation wind utilization rate model is: QO2 = K×QSO2 / ρ, where QO2 is the theoretical oxygen demand, QSO2 is the SO2 removal amount, ρ is the oxygen density, and K is a coefficient related to the stoichiometric ratio of the chemical reaction.

4. The integrated process optimization method for wet desulfurization intelligent gypsum oxidation and dehydration according to claim 3, characterized in that, The coefficient K takes the value of 0.5, and the oxygen density p takes the value of 1.43 kg / Nm 3 ; and further calculate theoretical air requirement QaN = QO2 / 21% and actual air requirement QaV = QaN × TV / 273.15 based on the theoretical oxygen requirement QO2, wherein TV is the ambient temperature at the suction inlet of the oxidation air fan, in K.

5. The integrated process optimization method for wet desulfurization intelligent gypsum oxidation and dehydration according to claim 4, characterized in that, Based on the actual required air volume QaV, the oxidation air volume is controlled by frequency conversion adjustment of the oxidation fan, and the sulfite concentration in the absorption tower slurry is stably controlled below 200 mg / L.

6. The integrated process optimization method for wet desulfurization intelligent gypsum oxidation and dehydration according to claim 1, characterized in that, In step (3), the operating parameters of the dewatering system include one or more of the following: vacuum degree, filter cake thickness, belt speed, and slurry density. The goal of dynamically adjusting the operating parameters of the dewatering system is to control the moisture content of gypsum to below 10%.

7. The integrated process optimization method for wet desulfurization intelligent gypsum oxidation and dehydration according to claim 1, characterized in that, In step (4), the oxidation-dehydration coupling model establishes a correlation by analyzing the effect of oxidation efficiency on gypsum crystallization and dehydration performance. The correlation is as follows: when the sulfite concentration exceeds 200 mg / L, the dehydration energy consumption increases by 15%-20%, and the gypsum moisture content rises to 12%-15%.

8. The integrated process optimization method for wet desulfurization intelligent gypsum oxidation and dehydration according to claim 1 or 7, characterized in that, In step (4), the goal of the linkage adjustment is to minimize the total energy consumption of the system and optimize the quality of the gypsum. The total energy consumption of the system E total =E ox +E de +E penalty ; where E ox For the energy consumption of the oxidation system, E de For the energy consumption of the dehydration system, E penalty This refers to the penalty costs incurred due to substandard quality.

9. The integrated process optimization method for wet desulfurization intelligent gypsum oxidation and dehydration according to claim 1, characterized in that, In step (5), the advanced process control adopts a multivariable model predictive control algorithm to achieve multivariable coordinated control of pH value, slurry supply, oxidation fan frequency and vacuum pump frequency.

10. The integrated process optimization method for wet desulfurization intelligent gypsum oxidation and dehydration according to claim 1, characterized in that, After implementing the method, the energy saving rate of the oxidation blower exceeds 20%, the energy saving rate of the vacuum pump reaches 35%, and the moisture content of gypsum is stably controlled below 9.5%.

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