Chlor-alkali chemical production desulfurization system and method

Abstract

The present disclosure relates to a chlor-alkali chemical production desulfurization system and method, which comprises a preparation unit, a desulfurization unit, a desulfurization liquid treatment unit and an intelligent control unit connected in sequence; the preparation unit comprises a slurry tank, a slurry pipeline and a production water pipeline, the slurry pipeline and the production water pipeline are respectively communicated with the slurry tank, and are used to reduce the concentration of the calcium carbide slurry in the absorbent to a preset value; the outlet of the slurry tank is communicated with the desulfurization unit; the desulfurization unit comprises a desulfurization tower and a first density meter arranged in the desulfurization tower; the desulfurization liquid treatment unit is used for solid-liquid separation of the desulfurization liquid generated in the desulfurization, and a first control valve is arranged at the liquid inlet end; the intelligent control unit is electrically connected with the first density meter and the first control valve, and is used for automatically controlling the action of the first control valve when the density value detected by the first density meter reaches a set threshold value. The chlor-alkali chemical production desulfurization system reduces the risk of pipeline blockage, and is beneficial to improving the production efficiency.

Description

Technical Field

[0001] This disclosure relates to the field of flue gas desulfurization technology, specifically to a desulfurization system and method for chlor-alkali chemical production. Background Technology

[0002] In the chlor-alkali chemical industry, flue gas desulfurization is a crucial step in achieving environmentally compliant production. Existing flue gas desulfurization systems generally employ the traditional carbide slag-gypsum wet desulfurization process to remove acidic components such as SO2 from the flue gas produced in chlor-alkali chemical plants.

[0003] In existing desulfurization systems, the absorbent is a calcium carbide slag slurry with a solid content of 30-50% and containing a small amount of sulfides and phosphides (of which the Ca(OH)2 content is about 10%), which is sent to the desulfurization unit via a pipeline. The flue gas is sent to the desulfurization unit after simple dust removal, where it reacts with the calcium carbide slag slurry to produce gypsum. The gypsum needs to be treated by the dewatering unit before being sent for disposal.

[0004] In actual operation, the calcium carbide slag slurry in the absorbent of the existing desulfurization system has a high solid content and complex composition, which makes it easy to deposit and form scale during transportation. At the same time, the gypsum particles generated by the desulfurization reaction are easy to adhere to the pipeline and the inner wall of the reaction equipment. The interaction between the two aggravates the blockage, requiring regular shutdown for dredging and maintenance, which reduces production efficiency. Summary of the Invention

[0005] The purpose of this disclosure is to provide a desulfurization system for chlor-alkali chemical production that reduces the risk of pipeline blockage and improves production efficiency.

[0006] To achieve the above objectives, this disclosure provides a desulfurization system for chlor-alkali chemical production, comprising a blending unit, a desulfurization unit, a desulfurization liquid treatment unit, and an intelligent control unit arranged sequentially. The blending unit prepares an absorbent using calcium carbide slag slurry and includes a slurry tank, a slurry pipeline, and a production water pipeline. The output ends of the slurry pipeline and the production water pipeline are respectively connected to the slurry tank for conveying raw materials to blend the absorbent and reducing the concentration of calcium carbide slag slurry in the absorbent to a preset value. The slurry tank has an outlet, which is connected to the desulfurization unit via a conveying pipeline. The desulfurization unit includes desulfurization... The desulfurization tower and a first density meter are installed inside the desulfurization tower. The absorbent entering the desulfurization tower comes into full contact with the SO2-containing flue gas to complete the desulfurization reaction. The first density meter is used to monitor the slurry concentration in the desulfurization tower in real time. The desulfurization liquid treatment unit is used to perform solid-liquid separation on the desulfurization liquid produced by the desulfurization reaction, and the inlet end of the desulfurization liquid treatment unit is equipped with a first control valve. The intelligent control unit is electrically connected to the first density meter and the first control valve respectively. When the density value detected by the first density meter reaches a set threshold, it automatically controls the first control valve to act, so that the desulfurization liquid enters the desulfurization liquid treatment unit.

[0007] Optionally, a second densitometer is installed inside the slurry tank. The second densitometer is electrically connected to the intelligent control unit and is used to monitor the absorbent density in real time and feed back a signal to the intelligent control unit. The intelligent control unit adjusts the raw material delivery rate of the slurry pipeline and the production water pipeline according to the absorbent density.

[0008] Optionally, the desulfurization unit further includes a spray assembly, which includes a plurality of spray pipes spaced apart along the height direction in the desulfurization tower. The plurality of spray pipes are connected to the bottom area of ​​the desulfurization tower through a circulation pipeline. Each spray pipe is provided with a plurality of nozzles spaced apart. A circulation pump is provided on the circulation pipeline.

[0009] Optionally, multiple circulation pumps are provided, and the multiple circulation pumps are arranged in parallel.

[0010] Optionally, the desulfurization tower is equipped with a demister, which is located above the spray assembly and is used to remove liquid droplets entrained in the flue gas.

[0011] Optionally, the desulfurization tower is equipped with multiple stirring devices, a pH meter, and a level gauge; the multiple stirring devices are all located below the spray assembly and are arranged at intervals; a second control valve is provided on the conveying pipeline, and the second control valve, the pH meter, and the level gauge are all electrically connected to the intelligent control unit.

[0012] Optionally, the desulfurization liquid treatment unit includes a neutralization tank, a buffer tank, and a plate and frame filter press arranged sequentially. The neutralization tank is connected to the circulation pipeline via a desulfurization liquid output pipeline. The first control valve is a three-way valve and is located at the connection between the desulfurization liquid output pipeline and the circulation pipeline to selectively connect the circulation pipeline to the internal circulation of the desulfurization tower or to the desulfurization liquid output pipeline. The inlet of the buffer tank is connected to the neutralization tank, and the outlet of the buffer tank is connected to the inlet of the plate and frame filter press via a first transfer pump. The plate and frame filter press is provided with a liquid outlet and a solid waste outlet. The liquid outlet is used to discharge the treated clear liquid, and the solid waste outlet is used to discharge the filtered solid material.

[0013] Optionally, the desulfurization system for chlor-alkali chemical production also includes an emergency pipeline. The emergency pipeline is equipped with a third control valve. One end of the emergency pipeline is connected in parallel between the conveying pipeline and the desulfurization tower, and the other end is used to connect to an external water supply device. The third control valve is electrically connected to the intelligent control unit.

[0014] Based on the above technical solution, this disclosure also provides a desulfurization method for chlor-alkali chemical production, used in the aforementioned desulfurization system for chlor-alkali chemical production, comprising the following steps:

[0015] Raw materials are transported to the slurry tank through the slurry pipeline and production water pipeline of the mixing unit, and the absorbent is mixed and the concentration of the calcium carbide slurry in the absorbent is reduced to the preset value. The prepared absorbent is transported to the desulfurization tower of the desulfurization unit via a pipeline; SO2-containing flue gas generated from chlor-alkali chemical production is sent into a desulfurization tower to fully contact with the absorbent and undergo a desulfurization reaction. The density of the slurry in the desulfurization tower is monitored in real time by the first density meter. When the detected density value reaches the set threshold, the intelligent control unit automatically controls the first control valve to send the desulfurization liquid into the desulfurization liquid treatment unit. The desulfurization solution is separated into solid and liquid components by a desulfurization solution treatment unit to complete the desulfurization process.

[0016] Optionally, the preset value is 3% to 5%; the set threshold is ≥1250kg / m³.

[0017] Through the above technical solution, the desulfurization system for chlor-alkali chemical production disclosed herein includes a blending unit, a desulfurization unit, and a desulfurization liquid treatment unit arranged in sequence, and also includes an intelligent control unit. The blending unit blends the absorbent to reduce the concentration of calcium carbide slag slurry to a preset value, thereby reducing the deposition and scaling of calcium carbide slag in the conveying pipeline and desulfurization tower from the source and avoiding the blockage risk caused by high solid content of the absorbent. The desulfurization unit includes a desulfurization tower and a first density meter installed in the desulfurization tower. The first density meter monitors the density of the slurry in the desulfurization tower in real time. The intelligent control unit is electrically connected to the first density meter and a first control valve. When the density value reaches a set threshold, the intelligent control unit automatically controls the first control valve to act, so that the desulfurization liquid in the desulfurization tower enters the desulfurization liquid treatment unit in a timely manner for solid-liquid separation, avoiding the blockage problem caused by excessive accumulation of solid impurities, which is conducive to improving the continuity of production and thus improving production efficiency.

[0018] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Attached Figure Description

[0019] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the desulfurization system for chlor-alkali chemical production provided in this embodiment.

[0020] Explanation of reference numerals in the attached drawings: 10. Mixing unit; 11. Slurry tank; 12. Slurry pipeline; 13. Production water pipeline; 14. Second density meter; 20. Desulfurization unit; 21. Desulfurization tower; 22. First density meter; 23. Stirring device; 24. Liquid level gauge; 30. Desulfurization liquid treatment unit; 31. Neutralization tank; 32. Buffer tank; 33. Plate and frame filter press; 331. Liquid outlet; 332. Solid waste outlet; 34. Desulfurization liquid output pipeline; 35. First transfer pump; 40. Transfer pipeline; 41. Second control valve; 42. Second transfer pump; 50. First control valve; 60. Spray assembly; 61. Spray pipe; 62. Circulation pipeline; 63. Circulation pump; 70. Demister; 80. Emergency pipeline; 81. Third control valve. Detailed Implementation

[0021] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0022] In this disclosure, unless otherwise stated, directional terms such as "inner" and "outer" are used relative to the contour of the corresponding component itself. Furthermore, the terms "first," "second," etc., used in this disclosure are for distinguishing one element from another and do not have sequential or importance implications. In the following description, when referring to the accompanying drawings, unless otherwise explained, the same reference numerals in different drawings denote the same or similar elements. The above definitions are for explanation and illustration only and should not be construed as limiting this disclosure.

[0023] According to exemplary embodiments of this disclosure, such as Figure 1As shown, a desulfurization system for chlor-alkali chemical production is provided, including a blending unit 10, a desulfurization unit 20, a desulfurization liquid treatment unit 30, and an intelligent control unit arranged sequentially. The blending unit 10 prepares an absorbent using calcium carbide slag slurry and includes a slurry tank 11, a slurry pipeline 12, and a production water pipeline 13. The output ends of the slurry pipeline 12 and the production water pipeline 13 are respectively connected to the slurry tank 11 for conveying raw materials to blend the absorbent and reducing the concentration of calcium carbide slag slurry in the absorbent to a preset value. The slurry tank 11 is provided with a liquid outlet, which is connected to the desulfurization unit 20 through a conveying pipeline 40. The desulfurization unit 20 includes a desulfurization tower. The absorbent entering the desulfurization tower 21 and the first density meter 22 installed inside the desulfurization tower 21 are used to fully contact the SO2-containing flue gas to complete the desulfurization reaction. The first density meter 22 is used to monitor the slurry concentration inside the desulfurization tower 21 in real time. The desulfurization liquid treatment unit 30 is used to perform solid-liquid separation on the desulfurization liquid produced by the desulfurization reaction. The inlet end of the desulfurization liquid treatment unit 30 is equipped with a first control valve 50. The intelligent control unit is electrically connected to the first density meter 22 and the first control valve 50 respectively. When the density value detected by the first density meter 22 reaches the set threshold, it automatically controls the first control valve 50 to act, so that the desulfurization liquid enters the desulfurization liquid treatment unit 30.

[0024] Through the above technical solution, the desulfurization system for chlor-alkali chemical production disclosed herein includes a blending unit 10, a desulfurization unit 20, and a desulfurization liquid treatment unit 30 arranged in sequence, and also includes an intelligent control unit. The blending unit 10 blends the absorbent to reduce the concentration of carbide slag slurry to a preset value, thereby reducing the deposition and scaling of carbide slag in the conveying pipeline 40 and the desulfurization tower 21 from the source and avoiding the blockage risk caused by high solid content of the absorbent. The desulfurization unit 20 includes a desulfurization tower 21 and a first density meter 22 installed in the desulfurization tower 21. The first density meter 22 monitors the density of the slurry in the desulfurization tower 21 in real time. The intelligent control unit is electrically connected to the first density meter 22 and the first control valve 50 respectively. When the density value reaches the set threshold, the intelligent control unit automatically controls the first control valve 50 to act, so that the desulfurization liquid in the desulfurization tower 21 enters the desulfurization liquid treatment unit 30 in time for solid-liquid separation, avoiding the blockage problem caused by excessive accumulation of solid impurities, which is conducive to improving the continuity of production and thus improving production efficiency.

[0025] In this disclosure, the mixing unit 10 includes a slurry tank 11, a slurry pipeline 12, and a production water pipeline 13. The slurry pipeline 12 is used to transport the calcium carbide slag raw material slurry (i.e., waste alkaline solution), and the production water pipeline 13 is used to transport production water. The output ends of both are connected to the slurry tank 11. By transporting the calcium carbide slag slurry and production water into the slurry tank 11, the absorbent is mixed, and the concentration of the calcium carbide slag slurry in the absorbent is reduced to a preset value (the preset value is lower than the existing solid content of 30-50%). In this way, the concentration of calcium carbide slag in the absorbent is reduced. The deposition in the pipeline, along with the low solids content of the absorbent, can reduce the amount of gypsum generated in the desulfurization reaction, control gypsum production from the source, and reduce the burden of solid waste disposal. On this basis, the density of the slurry in the desulfurization tower 21 is monitored in real time by the first density meter 22, and the intelligent control unit is linked to the first control valve 50 to realize the discharge of desulfurization liquid as needed, avoid excessive accumulation and adhesion of solid impurities, and at the same time, timely discharge of desulfurization liquid containing gypsum particles and solid-liquid separation can prevent the continuous generation and accumulation of gypsum in the desulfurization tower 21, and effectively control the total amount of gypsum generated.

[0026] According to exemplary embodiments of this disclosure, such as Figure 1 As shown, a second density meter 14 is installed inside the slurry tank 11. The second density meter 14 is electrically connected to the intelligent control unit and is used to monitor the absorbent density in real time and feed back the signal to the intelligent control unit. The intelligent control unit adjusts the raw material delivery rate of the slurry pipeline 12 and the production water pipeline 13 according to the absorbent density. Specifically, the second density meter 14 feeds back the monitored concentration signal to the intelligent control unit in real time. After receiving the signal, the intelligent control unit compares it with the preset absorbent concentration value. If the absorbent concentration is too high (close to the existing 30-50% solid content, which is prone to deposition), it controls the production water pipeline 13 to increase the production water delivery rate or controls the slurry pipeline 12 to reduce the calcium carbide slurry delivery rate. If the absorbent concentration is too low (which may affect the desulfurization efficiency), it adjusts in the opposite direction, thereby achieving precise and stable control of the absorbent concentration and ensuring that the absorbent is always within the preset low solid content range, reducing the risk of deposition and scaling from the source.

[0027] According to exemplary embodiments of this disclosure, such as Figure 1As shown, the desulfurization unit 20 may also include a spray assembly 60, which includes a plurality of spray pipes 61 spaced apart in the desulfurization tower 21 along the height direction. The plurality of spray pipes 61 are all connected to the bottom area in the desulfurization tower 21 through a circulation pipeline 62. Each spray pipe 61 is provided with a plurality of nozzles spaced apart. A circulation pump 63 is provided on the circulation pipeline 62. With the above setup, after the absorbent enters the bottom of the desulfurization tower 21 through the conveying pipe 40, it is driven by the circulating pump 63 and transported to each spray pipe 61 through the circulating pipe 62. Then, it is evenly sprayed into the desulfurization tower 21 through multiple nozzles on the spray pipe 61. After spraying, the absorbent comes into full contact with the SO2-containing flue gas flowing from bottom to top, completes the desulfurization reaction, and falls back to the bottom of the desulfurization tower 21. It is then circulated back to the spray assembly 60 through the circulating pipe 62, realizing the recycling of the absorbent and improving the utilization rate of the absorbent. At the same time, the multiple spray pipes 61 are arranged at intervals along the height and the multiple nozzles are set at intervals, which can make the absorbent form a uniform spray layer, increase the contact area and contact efficiency between the absorbent and the flue gas, ensure that acidic components such as SO2 are fully removed, reduce the residue of unreacted impurities, and further reduce the risk of blockage.

[0028] According to exemplary embodiments of this disclosure, such as Figure 1 As shown, multiple circulating pumps 63 can be provided, and these pumps 63 can be arranged in parallel. Specifically, the number of circulating pumps 63 can be three or more. This arrangement allows multiple circulating pumps 63 to operate simultaneously, increasing the circulation flow rate of the absorbent and ensuring the spraying effect. Furthermore, if one or more circulating pumps 63 fail, the remaining pumps 63 can continue to operate normally, preventing the absorption of the absorbent from being interrupted and the desulfurization reaction from stopping due to the failure of a single pump 63. This improves the continuity and reliability of the system operation and ensures production efficiency.

[0029] According to exemplary embodiments of this disclosure, such as Figure 1 As shown, a demister 70 can be installed inside the desulfurization tower 21. The demister 70 is located above the spray assembly 60. The demister 70 can efficiently remove absorbent droplets entrained in the flue gas, prevent solid impurities in the droplets from adhering to the inner wall of the subsequent flue gas exhaust pipe, further prevent pipe blockage, and at the same time prevent flue gas containing droplets from corroding the subsequent flue gas exhaust equipment.

[0030] According to exemplary embodiments of this disclosure, such as Figure 1As shown, the desulfurization tower 21 can be equipped with multiple stirring devices 23, pH meters, and level gauges 24. The multiple stirring devices 23 are all located below the spray assembly 60 and are arranged at intervals. A second control valve 41 is provided on the conveying pipeline 40, and the second control valve 41, pH meter, and level gauge 24 are all electrically connected to the intelligent control unit. In the above technical solution, the stirring device 23 can include a motor and a stirring body. The motor drives the stirring body to rotate, which is used to stir the absorbent (containing desulfurization liquid) at the bottom of the desulfurization tower 21, preventing solid impurities in the absorbent from depositing at the bottom of the desulfurization tower 21, while ensuring uniform absorbent concentration, ensuring sufficient desulfurization reaction, and reducing blockage caused by unreacted impurities.

[0031] In this disclosure, a pH meter is used to monitor the pH value of the slurry in the desulfurization tower 21 in real time and feed it back to the intelligent control unit to facilitate the control of the amount of absorbent entering the desulfurization tower 21 and ensure that the desulfurization reaction is in the optimal pH environment, such as maintaining the pH value in the desulfurization tower 21 between 5 and 6.

[0032] According to exemplary embodiments of this disclosure, such as Figure 1 As shown, the desulfurization liquid treatment unit 30 may include a neutralization tank 31, a buffer tank 32, and a plate and frame filter press 33 arranged sequentially. The neutralization tank 31 is connected to the circulation pipeline 62 through the desulfurization liquid output pipeline 34. The first control valve 50 is a three-way valve and is located at the connection between the desulfurization liquid output pipeline 34 and the circulation pipeline 62 to selectively connect the circulation pipeline 62 to the internal circulation of the desulfurization tower 21 or to the desulfurization liquid output pipeline 34. The inlet end of the buffer tank 32 is connected to the neutralization tank 31, and the outlet end of the buffer tank 32 is connected to the inlet end of the plate and frame filter press 33 through the first transfer pump 35. The plate and frame filter press 33 is provided with a liquid outlet 331 and a solid waste outlet 332. The liquid outlet 331 is used to discharge the treated clear liquid, and the solid waste outlet 332 is used to discharge the filtered solid material.

[0033] In the above technical solution, the neutralization tank 31 is used to receive the desulfurization liquid discharged from the desulfurization tower 21 and neutralize the desulfurization liquid to adjust the pH of the desulfurization liquid, so that the solid impurities (carbide slag, gypsum particles, etc.) in the desulfurization liquid are easier to settle, which facilitates subsequent solid-liquid separation. The first control valve 50 realizes the switching between circulation and slurry discharge. That is, when the slurry density in the desulfurization tower 21 does not reach the set threshold, the first control valve 50 connects to the circulation pipeline 62, so that the desulfurization liquid continues to circulate between the desulfurization tower 21 and the spray assembly 60 to make full use of the absorbent. When the slurry density reaches the set threshold, the first control valve 50 switches to connect to the desulfurization liquid output pipeline 34, so that the desulfurization liquid enters the neutralization tank 31 for neutralization treatment.

[0034] The buffer tank 32 buffers and allows the neutralized desulfurization liquid to settle further. The first transfer pump 35 sends the desulfurization liquid in the buffer tank 32 into the plate and frame filter press 33. The plate and frame filter press 33 separates the solid impurities in the desulfurization liquid from the supernatant through pressure filtration. The plate and frame filter press 33 is equipped with a liquid outlet 331 and a solid waste outlet 332. The liquid outlet 331 is used to discharge the clear liquid after filtration and send it to the deep biological treatment. The water after biological treatment can be reused, reducing the generation of waste liquid. The solid waste outlet 332 is used to discharge the solid material after filtration (including carbide slag, gypsum and solid waste). The solid material can be sent to the building materials industry as raw material for cement production.

[0035] like Figure 1 As shown, a second delivery pump 42 can be installed on the delivery pipeline 40. The second delivery pump 42 is electrically connected to the intelligent control unit. The second delivery pump 42 can provide active power to ensure that the absorbent maintains a stable flow rate in the delivery pipeline 40. The number of second delivery pumps 42 can be set to two and connected in parallel. In this way, when one of the second delivery pumps 42 fails, the remaining second delivery pumps 42 can work normally, ensuring the continuity and reliability of the system operation.

[0036] According to exemplary embodiments of this disclosure, such as Figure 1 As shown, the desulfurization system in chlor-alkali chemical production also includes an emergency pipeline 80. The emergency pipeline 80 is equipped with a third control valve 81. One end of the emergency pipeline 80 is connected in parallel between the delivery pipeline 40 and the desulfurization tower 21, and the other end is connected to an external water supply device. The third control valve 81 is electrically connected to the intelligent control unit. With this setup, when the delivery pipeline 40 becomes blocked and cannot deliver absorbent to the desulfurization tower 21, the intelligent control unit can automatically control the third control valve 81 to open, activating the external water supply device. Clean water or backup absorbent is then delivered to the desulfurization tower 21 through the emergency pipeline 80, ensuring the normal operation of the desulfurization reaction and preventing system shutdown.

[0037] Based on the above technical solution, this disclosure also provides a desulfurization method for chlor-alkali chemical production, used in the aforementioned desulfurization system for chlor-alkali chemical production, comprising the following steps: Raw materials are transported to the slurry tank 11 through the slurry pipeline 12 and the production water pipeline 13 of the mixing unit 10, and the absorbent is mixed and the concentration of the calcium carbide slurry of the absorbent is reduced to a preset value. The prepared absorbent is transported through the conveying pipeline 40 to the desulfurization tower 21 of the desulfurization unit 20; SO2-containing flue gas generated from chlor-alkali chemical production is sent into desulfurization tower 21 to fully contact with the absorbent and undergo a desulfurization reaction. The density of the slurry in the desulfurization tower 21 is monitored in real time by the first density meter 22. When the detected density value reaches the set threshold, the intelligent control unit automatically controls the first control valve 50 to send the desulfurization liquid into the desulfurization liquid treatment unit 30. The desulfurization solution is separated into solid and liquid components by the desulfurization solution treatment unit 30, thus completing the desulfurization process.

[0038] Through the above steps, the concentration of the absorbent calcium carbide slag slurry is first reduced to a preset value, which can be 3% to 5%. Compared with the traditional 10% calcium carbide slag slurry concentration, this can reduce deposition and scaling from the source. Density monitoring is performed by the first density meter 22 to achieve on-demand control of the desulfurization liquid. Then, the desulfurization liquid treatment unit 30 is used to perform solid-liquid separation of the desulfurization liquid, forming a full-process anti-clogging system from source control to process control to end-of-pipe treatment, which greatly reduces the risk of pipeline blockage.

[0039] In the above technical solution, when the threshold is set to ≥1250kg / m³ and the slurry density in the desulfurization tower 21 is ≥1250kg / m³, the content of solid impurities (including gypsum) is low, which will not cause pipeline and equipment blockage. At the same time, it can effectively avoid excessive accumulation and agglomeration of gypsum particles, reduce excessive gypsum production, and prevent gypsum from accumulating in large quantities in the system. When the slurry density in the desulfurization tower 21 reaches this threshold, the intelligent control unit controls the first control valve 50 to open and discharge the desulfurization liquid for treatment, ensuring stable system operation and preventing disorderly growth of gypsum.

[0040] The desulfurization system for chlor-alkali chemical production disclosed herein may also be equipped with a dust collector (not shown in the figure) and an induced draft fan (not shown in the figure). The outlet of the dust collector is connected to the inlet of the induced draft fan, and the outlet of the induced draft fan is connected to the desulfurization tower 21. In this way, the flue gas can be preliminarily de-dust-free by the dust collector before entering the desulfurization tower 21, thus avoiding affecting the subsequent desulfurization reaction.

[0041] like Figure 1 As shown, when the desulfurization system of this chlor-alkali chemical production is working, the flue gas is sent into the desulfurization tower 21 by the induced draft fan after being dusted by the dust collector. The flue gas runs from bottom to top, initially removing large particulate dust. Inside the desulfurization tower 21, the flue gas passes through multiple spray pipes 61 and comes into full contact with the absorbent droplets transported by the circulating pump 63, resulting in mass transfer and absorption reactions. After the reaction, the flue gas passes through the demister 70 at the top of the desulfurization tower 21 to remove entrained droplets. The purified flue gas is discharged into the atmosphere from the top chimney of the desulfurization tower 21. During the desulfurization process, the absorbent is sprayed and circulated in the desulfurization tower 21 by the circulating pump 63. The intelligent control unit controls the first control valve 50 to operate according to the slurry density in the desulfurization tower 21, and transports the desulfurization liquid to the neutralization tank 31 through the desulfurization liquid output pipe 34, avoiding the formation of gypsum crystals, reducing the amount of gypsum produced, and thus reducing the burden of solid waste disposal.

[0042] In summary, the desulfurization system in this chlor-alkali chemical production line helps reduce waste liquid discharge and solid waste accumulation, and improves the continuity of system operation.

[0043] The preferred embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0044] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0045] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A desulfurization system for chlor-alkali chemical production, characterized in that, It includes a mixing unit (10), a desulfurization unit (20), a desulfurization liquid treatment unit (30), and an intelligent control unit, which are connected in sequence. The mixing unit (10) uses carbide slag slurry to prepare absorbent and includes a slurry tank (11), a slurry pipeline (12), and a production water pipeline (13). The output ends of the slurry pipeline (12) and the production water pipeline (13) are respectively connected to the slurry tank (11) for transporting raw materials to mix the absorbent and reducing the concentration of carbide slag slurry in the absorbent to a preset value. The slurry tank (11) is provided with a liquid outlet, which is connected to the desulfurization unit (20) through a conveying pipeline (40). The desulfurization unit (20) includes a desulfurization tower (21) and a first density meter (22) installed in the desulfurization tower (21). The absorbent entering the desulfurization tower (21) comes into full contact with the SO2-containing flue gas to complete the desulfurization reaction. The first density meter (22) is used to monitor the slurry concentration in the desulfurization tower (21) in real time. The desulfurization liquid treatment unit (30) is used to perform solid-liquid separation on the desulfurization liquid generated by the desulfurization reaction, and the inlet end of the desulfurization liquid treatment unit (30) is provided with a first control valve (50). The intelligent control unit is electrically connected to the first density meter (22) and the first control valve (50) respectively, and is used to automatically control the first control valve (50) to act when the density value detected by the first density meter (22) reaches the set threshold, so that the desulfurization liquid enters the desulfurization liquid treatment unit (30).

2. The desulfurization system for chlor-alkali chemical production according to claim 1, characterized in that, The slurry tank (11) is equipped with a second density meter (14), which is electrically connected to the intelligent control unit. The second density meter (14) is used to monitor the absorbent density in real time and send a signal back to the intelligent control unit. The intelligent control unit adjusts the raw material delivery of the slurry pipeline (12) and the production water pipeline (13) according to the absorbent density.

3. The desulfurization system for chlor-alkali chemical production according to claim 1 or 2, characterized in that, The desulfurization unit (20) further includes a spray assembly (60), which includes a plurality of spray pipes (61) spaced apart along the height direction in the desulfurization tower (21). The plurality of spray pipes (61) are connected to the bottom area of ​​the desulfurization tower (21) through a circulation pipeline (62). Each spray pipe (61) is provided with a plurality of nozzles spaced apart. The circulation pipeline (62) is provided with a circulation pump (63).

4. The desulfurization system for chlor-alkali chemical production according to claim 3, characterized in that, Multiple circulating pumps (63) are provided, and the multiple circulating pumps (63) are arranged in parallel.

5. The desulfurization system for chlor-alkali chemical production according to claim 4, characterized in that, The desulfurization tower (21) is equipped with a demister (70), which is located above the spray assembly (60) and is used to remove liquid droplets entrained in the flue gas.

6. The desulfurization system for chlor-alkali chemical production according to claim 3, characterized in that, The desulfurization tower (21) is equipped with multiple stirring devices (23), pH meter and level gauge (24). The plurality of stirring devices (23) are all located below the spray assembly (60) and are arranged at intervals to each other; The delivery pipeline (40) is equipped with a second control valve (41), and the second control valve (41), the pH meter and the level gauge (24) are all electrically connected to the intelligent control unit.

7. The desulfurization system for chlor-alkali chemical production according to claim 3, characterized in that, The desulfurization liquid treatment unit (30) includes a neutralization tank (31), a buffer tank (32), and a plate and frame filter press (33) arranged in sequence. The neutralization tank (31) is connected to the circulation pipeline (62) through the desulfurization liquid output pipeline (34). The first control valve (50) is constructed as a three-way valve and is located at the connection between the desulfurization liquid output pipeline (34) and the circulation pipeline (62) to selectively connect the circulation pipeline (62) to the internal circulation of the desulfurization tower (21) or to the desulfurization liquid output pipeline (34). The inlet end of the buffer tank (32) is connected to the neutralization tank (31), and the outlet end of the buffer tank (32) is connected to the inlet end of the plate and frame filter press (33) through the first transfer pump (35). The plate and frame filter press (33) is provided with a liquid outlet (331) and a solid waste outlet (332). The liquid outlet (331) is used to discharge the treated clear liquid, and the solid waste outlet (332) is used to discharge the solid material after filtration.

8. The desulfurization system for chlor-alkali chemical production according to claim 1, characterized in that, The desulfurization system for chlor-alkali chemical production also includes an emergency pipeline (80), on which a third control valve (81) is provided. One end of the emergency pipeline (80) is connected in parallel between the conveying pipeline (40) and the desulfurization tower (21), and the other end is used to connect to an external water supply device. The third control valve (81) is electrically connected to the intelligent control unit.

9. A desulfurization method for chlor-alkali chemical production, used in the desulfurization system for chlor-alkali chemical production as described in claim 1, characterized in that, Includes the following steps: Raw materials are transported to the slurry tank (11) through the slurry pipeline (12) and production water pipeline (13) of the mixing unit (10), and the absorbent is mixed and the concentration of calcium carbide slurry in the absorbent is reduced to a preset value. The prepared absorbent is transported through the conveying pipeline (40) to the desulfurization tower (21) of the desulfurization unit (20); SO2-containing flue gas generated from chlor-alkali chemical production is sent into desulfurization tower (21) to fully contact with absorbent and undergo desulfurization reaction; The density of the slurry in the desulfurization tower (21) is monitored in real time by the first density meter (22). When the detected density value reaches the set threshold, the intelligent control unit automatically controls the first control valve (50) to send the desulfurization liquid into the desulfurization liquid treatment unit (30). The desulfurization liquid is separated into solid and liquid by the desulfurization liquid treatment unit (30) to complete the desulfurization.

10. The desulfurization method for chlor-alkali chemical production according to claim 9, characterized in that, The preset value is 3% to 5%; the set threshold is ≥1250 kg / m³.

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