Multi-stage desulfurization acid-making pretreatment system and pretreatment method

Abstract

The invention discloses a multistage desulfurization acid-making pretreatment system which comprises a clear liquid solid content on-line monitoring device, a model building system, a super centrifuge device, a sulfur melting kettle, a dilution kettle connected with the super centrifuge device, a multi-phase separator and an oxidation tower, the clear liquid solid content on-line monitoring device is used for detecting the solid content of liquid in real time, and the model building system is used for building a solid content adjusting model; the configuration of the solid content adjusting model is as follows: on the basis of the solid content detected by the clear liquid solid content on-line monitoring device and a preset multi-stage flow distribution strategy, system process parameters and the flow direction of liquid are adjusted, and the distribution proportion of the liquid flowing to the sulfur melting kettle and the oxidation tower is adjusted. According to the multistage desulfurization acid-making pretreatment system, the solid content of clear liquid can be monitored in real time, and the technological process is dynamically adjusted according to real-time data, so that stabilization of system operation is facilitated, and the sulfur recovery rate is increased. The invention also discloses a multistage desulfurization acid-making pretreatment method.

Description

Technical Field

[0001] The present invention belongs to the technical field of desulfurization and acid-making systems in chemical production, and in particular, relates to a multi-stage desulfurization and acid-making pretreatment system and a pretreatment method. Background Art

[0002] In the production process of the coking industry, coke oven gas contains a large amount of sulfides, which usually need to be removed through a desulfurization process to prevent pollution and recover useful sulfur resources. Traditional sulfur recovery processes usually include liquid absorption, flotation, centrifugal separation and other steps. These process flows are prone to a key problem when dealing with sulfur slag: the solid content in the liquid.

[0003] Solid content mainly refers to the mass concentration of sulfur slag particles, salts and other impurities suspended in the liquid. High solid content will bring the following series of problems:

[0004] Increased risk of blockage: Impurity particles in the liquid are easily deposited in pipelines and equipment, especially in oxidation towers and multiphase separators, which can cause serious blockages, leading to system shutdown and cleaning. In addition, some mature sulfur is granular and easily absorbs other impurities such as salts and tar, resulting in an increasing amount of slag;

[0005] Reduced processing efficiency: Too high solid content will lead to poor fluidity of the liquid, affect the sulfur recovery efficiency, and make the operation of subsequent reaction devices (such as oxidation towers) unstable;

[0006] Increased maintenance costs: Frequent equipment cleaning and maintenance directly increase operating costs and reduce the effective working time of the equipment.

[0007] The commonly used methods are usually inflexible and cannot be adjusted in real time according to production conditions. Some traditional systems are prone to reduced efficiency or equipment overload when dealing with fluctuations in solid content. Therefore, an improved technology is urgently needed: real-time monitoring of the solid content of the clear liquid and dynamic adjustment of the process flow based on real-time data. This will help stabilize system operation, improve sulfur recovery, and reduce equipment maintenance frequency and operating costs.

[0008] The Chinese patent with the application number 202223465176.3 discloses a raw material pretreatment device for coking desulfurization waste liquid and liquid sulfur incineration to produce acid, including a sulfur foam separator, a slurry tank, a sulfur melting tower, a clear liquid separation device, a liquid sulfur separator, and a clear liquid evaporation and concentration system. The sulfur foam sent from the desulfurization unit is fed into the sulfur foam separator. Part of the desulfurized liquid separated by the sulfur foam separator is sent back to the desulfurization unit, and part is sent to the slurry tank. The sulfur paste separated by the sulfur foam separator is sent to the slurry tank. The outlet of the slurry tank is connected to the sulfur melting tower. The supernatant of the sulfur melting tower is sent to the clear liquid separation device. The sulfur outlet at the bottom of the sulfur melting tower is connected to the liquid sulfur separator. The supernatant of the clear liquid separation device is sent to the clear liquid evaporation and concentration system. The technological process of this invention is simple and straightforward, the operation is simple, the heat utilization is reasonable, the production operation is continuous and stable, and the dual goals of energy conservation and consumption reduction and continuous and stable production operation are achieved. However, in actual production, the desulfurized liquid system contains a large amount of impurities, which are easy to accumulate in the system and need to be removed by the pretreatment device. Otherwise, the working conditions will easily deteriorate and affect the normal operation.

[0009] The Chinese patent with the application number 201610736196.X discloses a method for producing sulfuric acid from sulfur-containing waste liquid generated by the wet oxidation method of coal gas, which includes the following steps: (1) pretreatment of sulfur-containing waste liquid, (2) incineration of sulfur-containing waste liquid, (3) waste heat recovery, (4) wet purification, (5) drying, (6) contact catalytic oxidation, (7) absorption, (8) tail gas decontamination treatment. The sulfuric acid produced by the method provided by this invention can be supplied to the chemical production ammonium sulfate section as the raw material for ammonium sulfate products. Compared with the existing process, this method is a "clean production" process that does not generate waste liquid, can completely solve the pollution problem of coking desulfurization waste liquid, and meets the environmental protection requirements. It has great environmental, social and economic benefits. However, this invention needs to use sulfur-containing waste liquid, which has a high impurity content and complex composition. It belongs to wet pretreatment to produce acid, and a large amount of dilute acid will be generated. Therefore, a semi-dry pretreatment process can be considered to produce sulfuric acid.

[0010] The Chinese patent with the application number 201911237777.9 discloses a resource treatment process and device for coking desulfurization waste liquid. The process involves pre-treating the desulfurization waste liquid and adjusting its pH value to 4.0 - 5.5. Then, the desulfurization waste liquid is filtered, pressurized, and heat-exchanged with the desulfurization waste liquid after heat treatment and catalytic oxidation. The heat-exchanged desulfurization liquid is evaporated and concentrated. The condensate is directly subjected to biochemical treatment, and the concentrated liquid is subjected to catalytic conversion treatment. Ammonium sulfate solution is obtained by filtration and enters the ammonium sulfate mother liquor tank to recover ammonium sulfate products. This invention converts ammonium thiocyanate and ammonium thiosulfate into ammonium sulfate, achieving a mild conversion of salts and solving the problem of the backlog of ammonium thiocyanate. After salt extraction from the desulfurization waste liquid, the water can directly enter biochemical treatment, solving problems such as system swelling and water balance. It reduces environmental pollution and realizes the resource treatment of desulfurization waste liquid. It should be noted that coke oven gas contains a large amount of impurities. The comprehensive utilization of sulfur resources is based on reliable sulfur recovery, and it is necessary to control the impurity content in the system to avoid affecting subsequent processes. At the same time, this invention does not describe the treatment of sulfur foam, nor does it have relevant treatment methods for the sulfur slag generated during sulfur melting.

[0011] It is desired to provide a multi-stage desulfurization and acid-making pretreatment system and a pretreatment method, especially regarding how to optimize the operation efficiency of the system, prevent equipment blockage, and improve stability. Summary of the Invention

[0012] The present invention aims to solve at least one of the technical problems existing in the prior art. For this purpose, the present invention provides a multi-stage desulfurization and acid-making pretreatment system, aiming to improve the operation efficiency and stability of the system.

[0013] To achieve the above object, the technical solution adopted by the present invention is: a multi-stage desulfurization and acid-making pretreatment system, including an online monitoring device for the solid content of clear liquid, a model establishment system, a super centrifuge device, a sulfur melting kettle, a dilution kettle connected to the super centrifuge device, a multiphase separator connected to the dilution kettle, and an oxidation tower connected to the multiphase separator. The sulfur melting kettle is connected to the dilution kettle and the multiphase separator;

[0014] The online monitoring device for the solid content of clear liquid is configured to detect the solid content of the liquid in real time, and the model establishment system is configured to establish a solid content adjustment model;

[0015] The solid content adjustment model is configured to: based on the solid content detected by the online monitoring device for the solid content of clear liquid and a preset multi-stage diversion strategy, adjust the process parameters of the system and the flow direction of the liquid, so as to realize the adjustment of the liquid distribution ratio flowing into the sulfur melting kettle and the oxidation tower.

[0016] The dilution kettle is connected to the multiphase separator through a first pipeline, and a first valve is provided in the first pipeline;

[0017] The dilution kettle is connected to the molten sulfur kettle through a second pipeline, and a second valve is provided in the second pipeline;

[0018] The process parameters of the system include the opening degrees of the first valve and the second valve.

[0019] The multiphase separator is connected to the oxidation tower through a third pipeline, and the clear liquid separated from the upper part of the multiphase separator enters the oxidation tower through the third pipeline for further treatment.

[0020] The molten sulfur kettle and the multiphase separator are connected to the clarification kettle, and the clarification kettle is connected to the incinerator. The liquid sulfur formed at the bottom of the molten sulfur kettle and the multiphase separator enters the clarification kettle.

[0021] The on-line monitoring device for the solid content of the clear liquid is a microwave solid content monitor or an ultrasonic solid content analyzer.

[0022] The on-line monitoring device for the solid content of the clear liquid is arranged at the inlet of the multiphase separator and / or the outlet of the oxidation tower.

[0023] The preset multi-stage diversion strategy includes:

[0024] When the solid content S detected by the on-line monitoring device for the solid content of the clear liquid is less than the first set value C1, the liquid discharged from the dilution kettle is directly introduced into the oxidation tower after being treated by the multiphase separator;

[0025] When the solid content S detected by the on-line monitoring device for the solid content of the clear liquid is less than the second set value C2 and the solid content S is greater than or equal to the first set value C1, for the liquid discharged from the dilution kettle, a part of it is directly introduced into the oxidation tower after being treated by the multiphase separator, and the other part of the liquid enters the molten sulfur kettle;

[0026] When the solid content S detected by the on-line monitoring device for the solid content of the clear liquid is greater than or equal to the second set value C2 and the solid content S is less than the third set value C3, for the liquid discharged from the dilution kettle, all of it enters the molten sulfur kettle, or a part of it is directly introduced into the oxidation tower after being treated by the multiphase separator, and the other part of the liquid enters the molten sulfur kettle, and the volume of the liquid entering the molten sulfur kettle is greater than the volume of the liquid entering the multiphase separator.

[0027] The first set value C1 is set to 1% - 4%, the second set value C2 is set to 4% - 7%, and the third set value C3 is set to 7% - 10%.

[0028] The multiphase separator, the oxidation tower and the molten sulfur kettle are connected to the steam supply pipeline.

[0029] The present invention also provides a multi-stage desulfurization and sulfuric acid production pretreatment method, which uses the multi-stage desulfurization and sulfuric acid production pretreatment system and includes:

[0030] Add the desulfurized sulfur foam into the super centrifuge device for centrifugation treatment, and a small amount of dilute ammonia water for salt extraction can be used to wash the sulfur paste generated by centrifugation during centrifugation;

[0031] The sulfur paste discharged from the super centrifuge device enters the dilution kettle, and dilute ammonia water for salt extraction is added to the dilution kettle to stir the sulfur paste to form a dilute sulfur paste;

[0032] The dilute sulfur paste discharged from the dilution kettle enters the multiphase separator and / or the sulfur melting kettle for treatment;

[0033] The clear liquid discharged from the multiphase separator enters the oxidation tower, and the liquid sulfur discharged from the multiphase separator enters the clarification kettle;

[0034] The liquid sulfur discharged from the sulfur melting kettle enters the clarification kettle;

[0035] The liquid sulfur discharged from the clarification kettle enters the incinerator.

[0036] The multi-stage desulfurization and acid-making pretreatment system of the present invention can monitor the solid content of the clear liquid in real time and dynamically adjust the process flow according to the real-time data, which will help to stabilize the system operation, improve the sulfur recovery rate, and at the same time reduce the equipment maintenance frequency and operation cost. Brief Description of the Drawings

[0037] This specification includes the following drawings, and the shown contents are respectively:

[0038] Figure 1 It is a structural schematic diagram of the multi-stage desulfurization and acid-making pretreatment system of the present invention;

[0039] The marks in the figure are: 1. On-line monitoring device for the solid content of the clear liquid; 2. Super centrifuge device; 3. Sulfur melting kettle; 4. Dilution kettle; 5. Multiphase separator; 6. Oxidation tower; 7. Flow meter; 8. Clarification kettle; 9. Incinerator; 10. Pressure gauge. Detailed Embodiments

[0040] The following is a more detailed description of the specific embodiments of the present invention by referring to the drawings through the description of the embodiments, aiming to help those skilled in the art have a more complete, accurate and in-depth understanding of the concept and technical solution of the present invention and contribute to its implementation.

[0041] It should be noted that in the following embodiments, the so-called "first", "second" and "third" do not represent an absolute distinction relationship in structure and / or function, nor represent the execution order, but are only for the convenience of description.

[0042] First, as Figure 1As shown in the figure, an embodiment of the present invention provides a multi-stage desulfurization and sulfuric acid production pretreatment system, including an online monitoring device 1 for the solid content of the clear liquid, a model establishment system, a super centrifuge device 2, a sulfur melting kettle 3, a dilution kettle 4 connected to the super centrifuge device 2, a multiphase separator 5 connected to the dilution kettle 4, and an oxidation tower 6 connected to the multiphase separator 5. The sulfur melting kettle 3 is connected to the dilution kettle 4 and the multiphase separator 5. The online monitoring device 1 for the solid content of the clear liquid is configured to detect the solid content of the liquid in real time, and the model establishment system is configured to establish a solid content adjustment model. The solid content adjustment model is configured to: based on the solid content S detected by the online monitoring device 1 for the solid content of the clear liquid and a preset multi-stage diversion strategy, adjust the system process parameters and the flow direction of the liquid to achieve the adjustment of the liquid distribution ratio flowing into the sulfur melting kettle 3 and the oxidation tower 6.

[0043] Specifically, an embodiment of the present invention proposes a pretreatment system for a multi-stage desulfurization and sulfuric acid production system based on real-time monitoring of the solid content of the clear liquid and mathematical model control. Combining online detection and intelligent diversion strategies, it significantly improves the operation efficiency and stability of the desulfurization and sulfuric acid production system, and has strong practicality and application prospects.

[0044] As Figure 1 shown in the figure, the salt-extracted dilute ammonia water and desulfurized sulfur foam are added to the super centrifuge device 2 for centrifugation. The desulfurized sulfur foam is a solid-liquid mixture formed during the desulfurization process. It is formed by passing air or inhaling air in the regeneration tower or regeneration tank, and the sulfide in the desulfurization liquid undergoes an oxidation reaction under the action of a catalyst to convert the sulfide into elemental sulfur. At the same time, sulfur foam is formed through the flotation action of air and separated from the desulfurization liquid. The main components of the sulfur foam are tiny sulfur particles, residual air, and desulfurization liquid. The salt-extracted dilute ammonia water refers to the ammonia-containing condensate formed after salt extraction in the salt extraction process. The super centrifuge device 2 uses the salt-extracted dilute ammonia water generated in the salt extraction process to wash the super centrifuge while centrifuging, washing away the substances that are easy to form slag, and only leaving sulfur. The sulfur paste produced after centrifugation by the super centrifuge has a relatively high concentration, about 50-60% sulfur content, and poor fluidity. This sulfur paste will be sent to the dilution kettle 4.

[0045] As Figure 1 shown in the figure, the sulfur paste discharged from the super centrifuge device 2 enters the dilution kettle 4, and the salt-extracted dilute ammonia water is added to the dilution kettle 4 to stir and dilute the sulfur paste to form a dilute sulfur paste with a solid content of 30-40%.

[0046] As Figure 1As shown, the dilution kettle 4 is connected to the multiphase separator 5 through the first pipeline, and a first valve is arranged in the first pipeline; the dilute sulfur paste discharged from the dilution kettle 4 is sent into the multiphase separator 5 through the first pipeline, so as to increase the liquid sulfur production capacity of the multiphase separator 5. The multiphase separator 5 is used to remove sulfur and coarse particle sulfur slag from the dilute sulfur paste. By cooperating with the online monitoring device 1 for the solid content of the clear liquid, the preliminary melting and purification of the dilute sulfur paste from the dilution kettle 4 can be realized. Liquid sulfur is formed at the bottom of the multiphase separator 5, and the clear liquid separated from the upper part in the multiphase separator 5 enters the oxidation tower 6 for further treatment.

[0047] As Figure 1 shown, the dilution kettle 4 is connected to the sulfur melting kettle 3 through the second pipeline, and a second valve is arranged in the second pipeline. The sulfur melting kettle 3 is a key device for treating high-solid-content liquids. By heating and physical separation, the sulfur slag in the dilute sulfur paste is removed. Since the sulfur melting kettle 3 uses external jacket steam heating and the heating is relatively uniform, it can be used as a backup sulfur melting measure for the multiphase separator 5. If the solid content of the clear liquid at the outlet of the oxidation tower 6 is relatively high, a part of the dilute sulfur paste can be sent into the sulfur melting kettle 3 for heating and melting to reduce the load of the multiphase separator 5.

[0048] As Figure 1 shown, the outlet of the multiphase separator 5 is connected to the inlet of the oxidation tower 6 through the third pipeline, and the clear liquid separated from the upper part of the multiphase separator 5 enters the oxidation tower 6 through the third pipeline for further treatment. The oxidation tower 6 is used to complete the oxidation reaction of thiosulfate, and it is required that the liquid solid content brought by the clear liquid separated from the multiphase separator 5 is as low as possible to improve the production efficiency. A steam inner coil is arranged in the oxidation tower 6, and the liquid is heated through the steam inner coil to improve the oxidation reaction effect.

[0049] In the embodiment of the present invention, the system process parameters include the opening degrees of the first valve and the second valve. The first valve and the second valve are connected to the central control system, and the central control system is used to control the opening and closing of the first valve and the second valve and adjust the opening degrees of the first valve and the second valve. The solid content adjustment model sends the generated instruction to the central control system, and the central control system adjusts the opening and closing states of the first valve and the second valve and the opening degrees of the first valve and the second valve according to the instruction requirements. After the first valve is closed, the first pipeline is interrupted, and the dilute sulfur paste in the dilution kettle 4 cannot enter the multiphase separator 5 through the first pipeline; after the second valve is closed, the second pipeline is interrupted, and the dilute sulfur paste in the dilution kettle 4 cannot enter the sulfur melting kettle 3 through the second pipeline. By controlling the opening and closing of the first valve and the second valve, the flow direction of the liquid discharged from the dilution kettle 4 can be changed, and the liquid discharged from the dilution kettle 4 can be made to flow to the multiphase separator 5 and the sulfur melting kettle 3 simultaneously, or only control the liquid discharged from the dilution kettle 4 to flow to one of the multiphase separator 5 and the sulfur melting kettle 3. By adjusting the opening degrees of the first valve and the second valve, the total amount of the liquid flowing from the dilution kettle 4 to the sulfur melting kettle 3 and the multiphase separator 5 can be changed, and further the adjustment of the liquid distribution ratio flowing to the sulfur melting kettle 3 and the oxidation tower 6 can be realized, so as to achieve dynamic adjustment. When the solid content is low, it preferentially flows to the multiphase separator 5 to separate sulfur and clear liquid; when the solid content is high, the flow rate of the sulfur melting kettle 3 is increased.

[0050] As Figure 1 shown, the sulfur melting kettle 3 and the multiphase separator 5 are connected to the clarification kettle 8, and the clarification kettle 8 is connected to the incinerator 9. The liquid sulfur formed at the bottoms of the sulfur melting kettle 3 and the multiphase separator 5 enters the clarification kettle 8, and the liquid sulfur discharged from the clarification kettle 8 enters the incinerator 9.

[0051] In the embodiment of the present invention, the online monitoring device 1 for the solid content of the clear liquid is a microwave solid content monitor or an ultrasonic solid content analyzer. The online monitoring device 1 for the solid content of the clear liquid is equipped with a high-precision sensor and can measure the solid content of the liquid in real time.

[0052] In the embodiment of the present invention, as Figure 1 shown, the online monitoring device 1 for the solid content of the clear liquid is arranged at the inlet of the multiphase separator 5 and the outlet of the oxidation tower 6. The online monitoring device 1 for the solid content of the clear liquid arranged at the inlet of the multiphase separator 5 uses a microwave solid content monitor to monitor the solid content of the liquid at the inlet of the multiphase separator 5 (the solid content of the liquid detected at the inlet of the multiphase separator 5 is only for reference). The online monitoring device 1 for the solid content of the clear liquid arranged at the outlet of the oxidation tower 6 uses an ultrasonic solid content analyzer or a microwave solid content monitor for monitoring to monitor the solid content of the liquid at the outlet of the oxidation tower 6. Hereinafter, the solid content S detected by the online monitoring device 1 for the solid content of the clear liquid refers to the solid content of the liquid at the outlet of the oxidation tower 6.

[0053] In an embodiment of the present invention, the preset multi-stage shunt strategy includes:

[0054] When the solid content S detected by the online monitoring device 1 for the clear liquid solid content is less than the first set value C1, the liquid discharged from the dilution kettle is directly introduced into the oxidation tower 6 after being processed by the multiphase separator 5, the first valve is opened, and the second valve is closed; at this time, the liquid directly enters the oxidation tower 6 for the conventional desulfurization and sulfuric acid production reaction without shunt treatment;

[0055] When the solid content S detected by the online monitoring device 1 for the clear liquid solid content is less than the second set value C2 and the solid content S ≥ the first set value C1, for the liquid discharged from the dilution kettle 4, a part is directly introduced into the oxidation tower 6 after being processed by the multiphase separator 5, and the other part of the liquid enters the molten sulfur kettle 3, and both the first valve and the second valve are opened; the system flows part of the liquid to the molten sulfur kettle 3 and the other parts directly to the oxidation tower 6 to reduce the impact of high solid content on the system;

[0056] When the solid content S detected by the online monitoring device 1 for the clear liquid solid content is ≥ the second set value C2 and the solid content S < the third set value C3, for the liquid discharged from the dilution kettle 4, all enters the molten sulfur kettle 3, or a part is directly introduced into the oxidation tower 6 after being processed by the multiphase separator 5, and the other part of the liquid enters the molten sulfur kettle 3, and the volume of the liquid entering the molten sulfur kettle 3 is greater than the volume of the liquid entering the multiphase separator 5; both the first valve and the second valve are opened, and the opening degree of the first valve is less than the opening degree of the second valve to control the liquid to preferentially flow to the molten sulfur kettle 3 to prevent high-impurity liquid from directly entering the oxidation tower 6 and causing blockage of the subsequent pipeline.

[0057] In an embodiment of the present invention, the first set value C1 is set to 1% - 4%, the second set value C2 is set to 4% - 7%, and the third set value C3 is set to 7% - 10%.

[0058] In an embodiment of the present invention, the change trend of the solid content is predicted through the solid content adjustment model, and the opening degree of the valve is adjusted in advance to reduce the lag effect.

[0059] In an embodiment of the present invention, as Figure 1 shown, the multiphase separator 5, the oxidation tower 6 and the molten sulfur kettle 3 are connected to the steam supply pipeline, and the steam supply pipeline respectively transports the heating steam into the multiphase separator 5, the oxidation tower 6 and the molten sulfur kettle 3. After the supernatant separated by the multiphase separator 5 enters the oxidation tower 6, the heating steam enters the oxidation tower 6 through the steam supply pipeline. The pressure of the heating steam entering the multiphase separator 5, the oxidation tower 6 and the molten sulfur kettle 3 does not exceed 0.8 MPa (gauge), and the superheat of the steam is less than 15 °C.

[0060] In the embodiment of the present invention, the solid content adjustment model utilizes the solid content obtained by real-time monitoring and combines historical data for analysis. Through self-learning and adjustment, the best process control is achieved. When establishing the solid content adjustment model, the input variables involved are: the solid content of the dilute sulfur paste (referring to the solid content of the dilute sulfur paste discharged from the dilution kettle 4), the feed rate of the multiphase separator 5 (referring to the flow rate of the dilute sulfur paste entering the multiphase separator 5 measured by the flow meter 7 provided on the first pipeline), the inlet steam pressure of the heating steam entering the multiphase separator 5, the inlet steam pressure of the heating steam entering the oxidation tower 6, and the feed rate of the sulfur melting kettle 3 (referring to the flow rate of the dilute sulfur paste entering the sulfur melting kettle 3 measured by the flow meter 7 provided on the second pipeline); the output variable involved is: the best liquid solid content at the outlet of the oxidation tower, and it can be required that the liquid solid content is less than 5%. The constraint conditions involved are: the heating steam pressures entering the multiphase separator 5, the oxidation tower 6, and the sulfur melting kettle 3 do not exceed 0.8 MPa (gauge), and the steam superheat degree is less than 15 °C.

[0061] The establishment process of the solid content adjustment model is as follows:

[0062] 1.1 System Definition and Variables

[0063] 1.1.1 Target Variable

[0064] C out : Liquid solid content at the outlet of the oxidation tower (C out ≤5%)

[0065] 1.2.2 Regulation Variables

[0066] Q in : Flow rate of the dilute sulfur paste entering the multiphase separator (m 3 / h)

[0067] C in : Solid content of the dilute sulfur paste (30% - 40%, adjusted by the dilution kettle 4)

[0068] P steam,sep : Inlet steam pressure of the multiphase separator (MPa)

[0069] P steam,ox : Inlet steam pressure of the oxidation tower (MPa)

[0070] Q melter : Flow rate of the dilute sulfur paste diverted to the sulfur melting kettle (m 3 / h)

[0071] 1.2 Steady-State Empirical Model (Simplified Mechanism)

[0072] Assume that under steady state, the liquid solid content at the outlet of the oxidation tower is mainly affected by the following factors:

[0073] C out = k1*(ηsep *η ox / (C in *Q in ))+k2*(η melter / Q melter )

[0074] 1.2.1 Parameter Definition

[0075] η sep : Separation efficiency of the multiphase separator (positively correlated with the steam pressure, η sep = a*P steam,sep +b)

[0076] η ox : Reaction efficiency of the oxidation tower (positively correlated with the steam pressure, η ox = c*P steam,ox +d)

[0077] η melter : Deslagging efficiency of the sulfur melting kettle (fixed empirical value, such as η melter = 95%)

[0078] k1, k2: System coupling coefficient (fitted by historical data)

[0079] 1.3 Feedback Control Logic

[0080] 1.3.1 Control Objective

[0081] By adjusting Q in , C in , P steam,sep , P steam,ox , Q melter , make C out ≤5%.

[0082] 1.3.2 Hierarchical Regulation Rule (Based on the deviation e = C out -5%), as shown in Table 1

[0083] Table 1 Hierarchical Regulation Rule

[0084]

[0085]

[0086] In Table 1, different regulation actions are formulated according to the magnitude of the deviation e = C out -5%. For example:

[0087] When e ≤ -1%, reduce the energy consumption, decrease the steam inlet pressure of the multiphase separator and the flow rate of the dilute sulfur paste diverted to the sulfur melting kettle;

[0088] When -1% < e ≤ 0, maintain the steady state, fix the flow rate of the dilute sulfur paste and the solid content of the dilute sulfur paste entering the multiphase separator 5, and finely adjust the steam inlet pressure of the oxidation tower 6;

[0089] When 0 < e ≤ 2%, actively correct the deviation, and proportionally increase the steam inlet pressure of the multiphase separator and the flow rate of the dilute sulfur paste diverted to the sulfur melting kettle 3;

[0090] When e > 2%, enter the emergency mode, set the flow rate of the dilute sulfur paste diverted to the sulfur melting kettle to the maximum value, and raise the steam inlet pressures of the multiphase separator and the oxidation tower to the maximum value.

[0091] In the process of establishing the solid content adjustment model, by collecting historical data, preprocessing the collected data, and using the data fitting method to determine the system coupling coefficients k1 and k2. Fit the separation efficiency η of the multiphase separator according to the empirical formula sep and the reaction efficiency ηo of the oxidation tower x The relationship with the steam pressure (i.e., determine the values of a, b, c, and d). Establish the feedback control logic, determine the control objectives and formulate the hierarchical regulation rules, and design the control system logic according to the hierarchical regulation rules. Finally, establish a solid content adjustment model based on real-time monitoring and historical data to achieve the best process control.

[0092] Parameter calibration: k1, k2, a, b, c, d are obtained by regression of historical data (such as using the least squares method, etc.), and k p k q are all adjusted on-site (such as using the Ziegler-Nichols method, etc.).

[0093] In a second aspect, the embodiments of the present invention further provide a multi-stage desulfurization and sulfuric acid production pretreatment method, which uses the multi-stage desulfurization and sulfuric acid production pretreatment system with the above structure, and includes:

[0094] Adding the desulfurized sulfur foam into the super centrifuge device 2 for centrifugal treatment;

[0095] The sulfur paste discharged from the super centrifuge device 2 enters the dilution kettle 4, and the salt-extracted dilute ammonia water is added into the dilution kettle 4 to stir the sulfur paste to form a dilute sulfur paste;

[0096] The dilute sulfur paste discharged from the dilution kettle 4 enters the multiphase separator 5 and / or the sulfur melting kettle 3 for treatment;

[0097] The clear liquid discharged from the multiphase separator 5 enters the oxidation tower 6, and the liquid sulfur discharged from the multiphase separator 5 enters the clarification kettle 8;

[0098] The liquid sulfur discharged from the sulfur melting kettle 3 enters the clarification kettle 8;

[0099] The liquid sulfur discharged from the clarification kettle 8 enters the incinerator 9.

[0100] The above-mentioned multi-stage desulfurization and acid-making pretreatment system and pretreatment method have the following advantages:

[0101] 1. Real-time control and adjustment: Based on the intelligent analysis of real-time detection data and mathematical models, it can dynamically adjust the liquid treatment strategy to adapt to rapidly changing production conditions;

[0102] 2. Improve system stability: Accurately predict and control the diversion of liquid through the solid content model, effectively reduce system blockages, and improve the operating efficiency of equipment;

[0103] 3. Reduce maintenance costs: Automatic diversion reduces the impact on equipment, reduces system downtime and maintenance frequency, thereby reducing operating costs;

[0104] 4. Flexible process adaptability: The multi-stage diversion strategy of the system can flexibly adjust parameters according to actual production needs, improving production efficiency;

[0105] 5. Facilitate the realization of system automation and intelligent operation. By automatically controlling the solid content of the outlet clear liquid, the stable operation of the semi-dry acid-making pretreatment system is improved, ensuring that the least amount of sulfur slag enters the desulfurization system and salt extraction system to enhance the overall operating efficiency of the desulfurization system. Through continuous self-learning and iteration of the system, the optimization of the operation of the entire desulfurization system and acid-making system is achieved.

[0106] Embodiment

[0107] In an application in a certain coking plant, the set parameters are as follows:

[0108] The first set value C1 is set to 2%, the second set value C2 is set to 5%, and the third set value C3 is set to 7%.

[0109] The solid content S of the liquid is detected in real time through an on-line monitoring device, and the system process parameters and the flow direction of the liquid are adjusted in combination with the solid content adjustment model:

[0110] S < C1: The liquid directly enters the oxidation tower 6.

[0111] C1 ≤ S < C2: The liquid distribution ratio is 40% flowing to the sulfur melting kettle 3 and 60% entering the oxidation tower 6.

[0112] C2 ≤ S < C3: The liquid distribution ratio is 80% or even 100% flowing to the sulfur melting kettle 3 to treat the liquid with high impurity content.

[0113] By adjusting the solid content threshold and the diversion ratio, the system can flexibly adapt to different production conditions, effectively improving the overall operating efficiency of the system and reducing the frequency of equipment blockages.

[0114] The present invention has been described exemplarily in conjunction with the accompanying drawings. Obviously, the specific implementation of the present invention is not limited by the above methods. As long as various non-substantive improvements are made by adopting the method concept and technical solution of the present invention; or without improvement, the above concept and technical solution of the present invention are directly applied to other occasions, they are all within the protection scope of the present invention.

Claims

1. Multi-stage desulfurization and sulfuric acid production pretreatment system, characterized in that, It includes an on-line monitoring device for the solid content of clear liquid, a model establishment system, a super centrifuge device, a sulfur melting kettle, a dilution kettle connected to the super centrifuge device, a multiphase separator connected to the dilution kettle, and an oxidation tower connected to the multiphase separator. The sulfur melting kettle is connected to the dilution kettle and the multiphase separator; The on-line monitoring device for the solid content of clear liquid is set to detect the solid content of the liquid in real time, and the model establishment system is set to establish a solid content adjustment model; The solid content adjustment model is configured to: based on the solid content detected by the on-line monitoring device for the solid content of clear liquid and a preset multi-stage diversion strategy, adjust the system process parameters and the flow direction of the liquid, so as to realize the adjustment of the liquid distribution ratio flowing into the sulfur melting kettle and the oxidation tower.

2. The multi-stage desulfurization and sulfuric acid production pretreatment system according to claim 1, wherein The dilution kettle is connected to the multiphase separator through a first pipeline, and a first valve is arranged in the first pipeline; The dilution kettle is connected to the sulfur melting kettle through a second pipeline, and a second valve is arranged in the second pipeline; The system process parameters include the opening degrees of the first valve and the second valve.

3. The multi-stage desulfurization and sulfuric acid production pretreatment system according to claim 1, wherein, The multiphase separator is connected to the oxidation tower through a third pipeline, and the clear liquid separated from the upper part of the multiphase separator enters the oxidation tower through the third pipeline for further treatment.

4. The multi-stage desulfurization and sulfuric acid production pretreatment system according to any one of claims 1 to 3, characterized in that, The sulfur melting kettle and the multiphase separator are connected to a clarification kettle, and the clarification kettle is connected to an incinerator. The liquid sulfur formed at the bottom of the sulfur melting kettle and the multiphase separator enters the clarification kettle.

5. The multi-stage desulfurization and sulfuric acid production pretreatment system according to any one of claims 1 to 3, characterized in that, The on-line monitoring device for the solid content of clear liquid is a microwave solid content monitor or an ultrasonic solid content analyzer.

6. The multi-stage desulfurization and sulfuric acid production pretreatment system according to any one of claims 1 to 3, characterized in that, The on-line monitoring device for the solid content of clear liquid is arranged at the inlet of the multiphase separator and / or the outlet of the oxidation tower.

7. The multi-stage desulfurization and sulfuric acid production pretreatment system according to any one of claims 1 to 3, characterized in that, The preset multi-stage diversion strategy includes: When the solid content S detected by the on-line monitoring device for the solid content of clear liquid < the first set value C1, the liquid discharged from the dilution kettle directly enters the oxidation tower after being processed by the multiphase separator; When the solid content S detected by the on-line monitoring device for the solid content of clear liquid < the second set value C2 and the solid content S ≥ the first set value C1, for the liquid discharged from the dilution kettle, a part of it directly enters the oxidation tower after being processed by the multiphase separator, and the other part of the liquid enters the sulfur melting kettle; When the solid content S detected by the on-line monitoring device for the solid content of clear liquid ≥ the second set value C2 and the solid content S < the third set value C3, for the liquid discharged from the dilution kettle, all of it enters the sulfur melting kettle, or a part of it directly enters the oxidation tower after being processed by the multiphase separator, and the other part of the liquid enters the sulfur melting kettle, and the volume of the liquid entering the sulfur melting kettle is greater than the volume of the liquid entering the multiphase separator.

8. The multi-stage desulfurization and acid-making pretreatment system according to claim 7, wherein The first set value C1 is set to 1% - 4%, the second set value C2 is set to 4% - 7%, and the third set value C3 is set to 7% - 10%.

9. The multi-stage desulfurization and sulfuric acid production pretreatment system according to any one of claims 1 to 8, characterized in that, The multiphase separator, the oxidation tower and the sulfur melting kettle are connected to a steam supply pipeline.

10. Multistage desulfurization and sulfuric acid production pretreatment method, characterized in that, Adopt the multi-stage desulfurization and sulfuric acid production pretreatment system according to any one of claims 1 to 9, and it includes: Adding desulfurized sulfur foam into the super centrifuge device for centrifugal treatment; The sulfur paste discharged from the super centrifuge device enters the dilution kettle, and desalted dilute ammonia water is added into the dilution kettle to stir the sulfur paste to form dilute sulfur paste; The dilute sulfur paste discharged from the dilution kettle enters the multiphase separator and / or the sulfur melting kettle for treatment; The clear liquid discharged from the multiphase separator enters the oxidation tower, and the liquid sulfur discharged from the multiphase separator enters the clarification kettle; The liquid sulfur discharged from the sulfur melting kettle enters the clarification kettle; The liquid sulfur discharged from the clarification kettle enters the incinerator.

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