A purification device and purification method for ammonia desulfurization deteriorated slurry

Abstract

The present application relates to a device and method for purifying deteriorated slurry of ammonia desulfurization, belonging to the field of flue gas treatment. The device comprises, in sequence, an absorption spray liquid storage tank, an oxidation converter, a concentrated liquid circulating tank, a performance improver, and a precipitator. The absorption spray liquid storage tank is connected with an absorption spray layer and an absorption liquid receiving tray. The concentrated liquid circulating tank is connected with an externally supplied energy desulfurization crystallizer, a solidification device, a precipitator, and a solid-liquid separator. The concentrated liquid circulating tank is connected with an inclined plate at the bottom and middle of a desulfurization tower. The precipitator outlet is provided with a clarified liquid outlet and a precipitate discharge outlet. The externally supplied energy desulfurization crystallizer is connected with the solid-liquid separator. The solid-liquid separator and the solidification device are connected with a solidifier. The concentrated liquid circulating tank and the performance improver are provided with an additive inlet. The method comprises primary purification, secondary purification, tertiary purification, quaternary purification, and quinary purification. The present application is used for treating ammonia desulfurization slurry with different degrees of deterioration and solving different effects caused by slurry deterioration during desulfurization operation.

Description

Technical Field

[0001] This invention belongs to the field of flue gas treatment equipment, specifically, it relates to a purification device and method for deteriorated slurry in ammonia desulfurization. Background Technology

[0002] In the current context of increasingly diverse energy transition and environmental governance technologies, co-firing non-fossil fuels and waste into boilers has become an important approach. However, this approach also faces challenges and limitations. Boiler flue gas after co-firing non-fossil fuels and waste contains a variety of complex impurities, resulting in superimposed pollution of the original flue gas in the desulfurization tower. Due to the lack of in-depth research on the variability of coal fuels and the impurities generated in the flue gas after combustion, these polluting gases enter the desulfurization tower along with the boiler flue gas. After contacting the absorption and concentration spray liquid, they generate desulfurization deterioration slurry to varying degrees. Ammonia desulfurization is a closed-loop circulation system with no wastewater discharge during operation. As the operating time increases, the impurities generated in the circulating liquid continuously change, and the circulating liquid also becomes variable. The industry also lacks in-depth research on this. If the deteriorated circulating slurry is not treated, once the deterioration of the circulating liquid intensifies, the negative impact will be transmitted layer by layer, leading to abnormal crystallization morphology and crystallization rate of ammonium sulfate fertilizer, decreased product quality, continuous decline in desulfurization efficiency, system material imbalance, and potential safety hazards in operating equipment, among other problems. These problems severely restrict the further promotion and application of ammonia desulfurization technology in actual ultra-low emission operations. Currently, given the varying degrees of deterioration and characteristics of ammonia desulfurization circulating fluids, it is difficult to achieve effective purification using the same equipment, a single method, or traditional approaches.

[0003] Given the importance of ensuring the long-term stable operation of desulfurization systems, it is particularly necessary to develop a purification device and method for deteriorated slurry in ammonia-based desulfurization processes to treat slurries of varying degrees of deterioration. This will provide practical equipment and technology to address the current challenges and contribute to the optimization and sustainable development of desulfurization processes.

[0004] Invention Patent Content In order to overcome the problems existing in the background technology, the present invention provides a purification device and purification method for deteriorated slurry of ammonia desulfurization. By designing a connection method for oxidation equipment, purification equipment, crystallization equipment and other equipment capable of handling deteriorated slurry of ammonia desulfurization and a four-stage purification method, the purpose of treating ammonia desulfurization slurry with different degrees of deterioration is achieved.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution: A purification device for deteriorated slurry in ammonia desulfurization, comprising, in sequence, an absorption spray liquid storage tank 1, an oxidation converter 2, a concentrate circulation tank 3, a performance improver 4, and a precipitator 5; the absorption spray liquid storage tank 1 is connected to the absorption spray layer 22 and the absorption receiving tray 23; the concentrate circulation tank 3 is connected to the externally powered desulfurization crystallizer 7, the solidification device 8, the precipitator 5, and the solid-liquid separator 6; the concentrate circulation tank 3 is also connected to the bottom of the desulfurization tower 18 and... The desulfurization tower 18 is connected to the inclined plate 24 in the middle; the precipitator 5 has a clarified liquid outlet 27 and a precipitate outlet 28 at its outlet. The clarified liquid outlet 27 is connected to the concentrate circulation tank 3 and the externally powered desulfurization crystallizer 7, respectively. The precipitate outlet 28 is connected to the solid-liquid separator 6 and the solidification device 8, respectively. The externally powered desulfurization crystallizer 7 is connected to the solid-liquid separator 6. The solid-liquid separator 6 and the solidification device 8 are both connected to the solidifier 17. The concentrate circulation tank 3 and the performance improver 4 are equipped with an additive inlet 21.

[0006] Furthermore, the oxidation converter 2 is equipped with an oxidation power tank 10 with a built-in aerator 11. One end of the oxidation power tank 10 is connected to the absorption spray liquid storage tank 1, and the other end is connected to the concentrate circulation tank 3. The aerator 11 is connected to the oxidation wind power source 13 through the air duct 12.

[0007] Furthermore, the solid-liquid separator 6 includes a smart filter 14, a vortex separator 15, and a dryer 16. The smart filter 14 and the vortex separator 15 are respectively connected to the externally powered desulfurization crystallizer 7, the concentrate circulation tank 3, and the sediment discharge outlet 28 through the conveying pipe 9. The smart filter 14 and the vortex separator 15 are then respectively connected to the dryer 16 through the conveying pipe 9. The dryer 16 is connected to the solidifier 17.

[0008] Furthermore, the concentrated liquid circulation tank 3, the performance improver 4, and the precipitator 5 are equipped with a stirrer 19; the absorption spray liquid storage tank 1, the oxidation converter 2, the concentrated liquid circulation tank 3, the performance improver 4, and the precipitator 5 are equipped with a control device 26; the bottom of the precipitator 5 is provided with an inclined plate 24 that slopes towards the outlet end.

[0009] A purification method for deteriorated slurry in ammonia desulfurization is characterized in that the purification method includes primary purification, secondary purification, tertiary purification, quaternary purification, or quinary purification.

[0010] Furthermore, the primary purification includes the following steps: S1 Oxidation: The deteriorated slurry from the ammonia desulfurization process, which comes from the absorption receiving pan 23, is sent to the absorption spray liquid storage tank 1 and then to the oxidation converter 2 for oxidation; S2 Concentration and Crystallization: The oxidized liquid is sent to the concentrate circulation tank 3 and then sequentially to the bottom of the desulfurization tower 18 and the concentration spray layer 20. After contacting the flue gas from the flue gas inlet 25, it reaches the inclined plate 24 in the middle of the desulfurization tower 18 and is sent back to the concentrate circulation tank 3. The concentration step is repeated until crystals are formed. When the crystal-liquid ratio is greater than 30% v / v, the concentrate containing crystals is sent to the next step of dehydration; S3 Dehydration: The slurry containing solids after concentration and crystallization is sent to the solid-liquid separator 6. The solids are sent to the solid feeder 17, and the liquid is sent to the concentrate circulation tank 3 for recycling.

[0011] Furthermore, the secondary purification includes the following steps: S1 Oxidation, which is the same as the oxidation step in the primary purification; S2 Performance Improvement, where the oxidized liquid is sequentially sent to the concentrate circulation tank 3 and the performance improver 4 for performance improvement; S3 Supernatant Treatment, where the improved solution is sent to the precipitator 5 for sedimentation, and the separated supernatant is discharged through the clarified liquid outlet 27; S4 Concentration and Crystallization, where the discharged supernatant is sent to the concentrate circulation tank 3, then sequentially transported to the bottom of the desulfurization tower 18 and the concentration spray layer 20, where it comes into contact with the hot flue gas from the flue gas inlet 25 and then reaches the inclined plate 24 in the middle of the desulfurization tower 18, before being sent back to the concentrate circulation tank 3. The concentration step is repeated until the concentrate forms crystals. When the crystal-liquid ratio is greater than 30% v / v, the concentrate containing crystals is sent to the next step for dehydration. S5 Dehydration, which is consistent with the S3 dehydration step in the primary purification.

[0012] Furthermore, the three-stage purification includes the following steps: S1 oxidation, which is consistent with the S1 oxidation step of the first-stage purification; S2 concentration and crystallization, the oxidized liquid is sent to the concentration liquid circulation tank 3, and then sequentially sent to the bottom of the desulfurization tower 18 and the concentration spray layer 20. After contacting the hot flue gas from the flue gas inlet 25, it reaches the inclined plate 24 in the middle of the desulfurization tower 18, and then is sent back to the concentration liquid circulation tank 3. The concentration step is repeated until the ammonium sulfate content of the concentrated liquid is 3.00mol / L to 3.85mol / L. The concentrated liquid is then sent to the externally powered desulfurization crystallizer 7 for crystallization. When the crystal-liquid ratio is greater than 30%v / v, it enters the next step S3 dehydration; S3 dehydration, the slurry containing solids after the concentrated liquid crystallization is sent to the solid-liquid separator 6. The solids are sent to the solid feeder 17, and the liquid is sent to the concentration liquid circulation tank 3 for recycling.

[0013] Furthermore, the four-stage purification includes the following steps: S1 oxidation, S2 performance improvement, and S3 supernatant treatment. These three steps are consistent with the S1 oxidation, S2 performance improvement, and S3 supernatant treatment steps of the second-stage purification; S4 precipitate treatment, after the supernatant treatment is completed, the precipitate at the bottom is discharged through the precipitate discharge outlet 28; S5 concentration and crystallization, the discharged supernatant is sent to the concentration liquid circulation tank 3, and then sequentially transported to the bottom of the desulfurization tower 18 and the concentration spray layer 20, where it comes into contact with the hot flue gas from the flue gas inlet 25 to achieve desulfurization. The inclined plate 24 in the middle of the sulfur tower 18 is then sent back to the concentrate circulation tank 3 to repeat the concentration step until the ammonium sulfate content of the concentrated liquid is between 3.00 mol / L and 3.85 mol / L. The concentrated liquid is then sent to the externally powered desulfurization crystallizer 7 for crystallization. When the crystal-liquid ratio is greater than 30% v / v, it enters the next step S6 for dehydration. In S6 dehydration, the solid-liquid mixture from the externally powered desulfurization crystallizer 7 and the precipitate outlet 28 is sent to the solid-liquid separator 6 for separation. The solid is transported to the solid feeder 17, and the liquid is transported to the concentrate circulation tank 3 for recycling.

[0014] Furthermore, the five-stage purification includes the following steps: S1 oxidation, which is the same as the S1 oxidation in the first-stage purification; S2 concentration, after the oxidation is completed, the oxidizing liquid is sent to the concentration liquid circulation tank 3, and then sequentially sent to the bottom of the desulfurization tower 18 and the concentration spray layer 20. After contacting the hot flue gas from the flue gas inlet 25, it reaches the inclined plate 24 in the middle of the desulfurization tower 18, and then is sent back to the concentration liquid circulation tank 3 to repeat the concentration step. The ammonium sulfate content is 3.00mol / L to 3.85mol / L, and then it enters the solidification step; S3 solidification, the concentration liquid is sent to the solidification device 8, and the solid produced by the solidification device 8 is transported to the solidifier 17.

[0015] This invention organically integrates a purification device for deteriorated slurry in ammonia desulfurization, including an absorption spray liquid storage tank 1, an oxidation converter 2, a concentrate circulation tank 3, a performance improver 4, and a precipitator 5, with external devices such as a desulfurization tower 18, a solid-liquid separator 6, an externally powered desulfurization crystallizer 7, a solidification device 8, and a solidifier 17, through a layered connection. This layered connection effectively addresses ammonia desulfurization slurry with varying degrees of deterioration. Compared to traditional methods, this invention offers significant advantages: flexible device connection, simple operation, multi-stage combination, and multiple process flows and treatment methods. It effectively solves problems encountered in actual desulfurization operation and efficiently treats deteriorated slurry. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the main structure of the present invention; Figure 2 This is a schematic diagram of the oxidation converter structure of the present invention; Figure 3This is a schematic diagram of the solid-liquid separator structure of the present invention; In the diagram, 1-Absorption spray liquid storage tank, 2-Oxidation converter, 3-Concentrated liquid circulation tank, 4-Performance improver, 5-Sedimenter, 6-Solid-liquid separator, 7-Externally powered desulfurization crystallizer, 8-Curement device, 9-Transfer pipe, 10-Oxidation power tank, 11-Aerator, 12-Ventilation duct, 13-Oxidation air power source, 14-Intelligent filter, 15-Fluid separator, 16-Dryer, 17-Solidifier, 18-Desulfurization tower, 19-Agitator, 20-Concentrated spray layer, 21-Additive inlet, 22-Absorption spray layer, 23-Absorption receiving tray, 24-Inclined plate, 25-Flue gas inlet, 26-Control device, 27-Clarified liquid outlet, 28-Sediment discharge outlet Detailed Implementation

[0017] To make the objectives, technical solutions, and beneficial effects of this technology clearer, the preferred embodiments of this technology will be described in detail below to facilitate understanding by those skilled in the art.

[0018] like Figure 1 As shown, a purification device for deteriorated slurry in ammonia desulfurization is disclosed. The purification device includes an absorption spray liquid storage tank 1, an oxidation converter 2, a concentrate circulation tank 3, a performance improver 4, and a sedimentation tank 5. The absorption spray liquid storage tank 1, oxidation converter 2, concentrate circulation tank 3, performance improver 4, and sedimentation tank 5 are connected in sequence. Agitators 19 are installed inside the concentrate circulation tank 3, performance improver 4, and sedimentation tank 5. A control device 26 is provided in the absorption spray liquid storage tank 1, oxidation converter 2, concentrate circulation tank 3, performance improver 4, and sedimentation tank 5. An inclined plate 24 is provided at the bottom of the sedimentation tank 5, and it is inclined towards the outlet end.

[0019] like Figure 2 As shown, an oxidation power tank 10 with a built-in aerator 11 is provided in the oxidation converter 2. One end of the oxidation power tank 10 is connected to the absorption spray liquid storage tank 1, and the other end is connected to the concentrate circulation tank 3. The aerator 11 is connected to the oxidation wind power source 13 through the air duct 12.

[0020] The absorption spray liquid storage tank 1 is connected to the absorption spray layer 22 and the absorption receiving tray 23 respectively; the concentrate circulation tank 3 is connected to the externally powered desulfurization crystallizer 7, the solidification device 8, the precipitator 5 and the solid-liquid separator 6 respectively; the concentrate circulation tank 3 is also connected to the bottom of the desulfurization tower 18 and the inclined plate 24 in the middle of the desulfurization tower 18 respectively; the outlet of the precipitator 5 is provided with a clarified liquid outlet 27 and a precipitate outlet 28, the clarified liquid outlet 27 is connected to the concentrate circulation tank 3 and the externally powered desulfurization crystallizer 7 respectively, and the precipitate outlet 28 is connected to the solid-liquid separator 6 and the solidification device 8 respectively; the externally powered desulfurization crystallizer 7 is connected to the solid-liquid separator 6; the solid-liquid separator 6 and the solidification device 8 are both connected to the solidifier 18; the concentrate circulation tank 3 and the performance improver 4 are provided with an additive inlet 21.

[0021] like Figure 3 As shown, the solid-liquid separator 6 includes a smart filter 14, a vortex separator 15, and a dryer 16. The smart filter 14 and the vortex separator 15 are respectively connected to the externally powered desulfurization crystallizer 7, the concentrate circulation tank 3, and the sediment discharge outlet 28 through the conveying pipe 9. The smart filter 15 and the vortex separator 16 are then respectively connected to the dryer 16 through the conveying pipe 9. The dryer 16 is connected to the solidifier 17.

[0022] All of the above connections are achieved through delivery pipe 9, which is equipped with valves and pumps.

[0023] A purification method for deteriorated slurry in ammonia desulfurization includes primary purification, secondary purification, tertiary purification, quaternary purification and quinary purification.

[0024] Level 1 purification is mainly applicable to slightly deteriorated liquids. Compared with normal liquids, slightly deteriorated liquids are slightly turbid, contain a small amount of suspended matter and heavy metal ions, and are slightly acidic. The diameter of crystal grains shrinks from the normal 0.20mm-0.25mm to 0.15mm-0.18mm, the solid-liquid separation efficiency is also lower than that of normal slurry, and the crystal grain settling velocity drops from the normal 10cm / s to 1cm / s. Specifically, the process includes the following steps: S1 Oxidation: The solution in the absorption spray liquid storage tank 1 is sent to the absorption spray layer 22 via the conveying pipe 9. After contacting the flue gas in the desulfurization tower 18, it deteriorates. The deteriorated liquid flows back from the absorption receiving pan 23 to the absorption spray liquid storage tank 1 via the conveying pipe 9. Further, the pH value can be adjusted to 4-6 using the control device 26 of the absorption spray liquid storage tank 1. After repeated absorption spraying, impurities gradually accumulate in the absorption spray liquid storage tank 1, forming a deteriorated slurry for ammonia desulfurization. The deteriorated slurry is sent to the oxidation converter 2 via the conveying pipe 9 for oxidation. During the oxidation process, the ammonium sulfate concentration is adjusted from 0.83 mol / L to 2.01 mol / L using the control device 26. When the oxidation rate reaches 98.5%, the oxidation process continues. The above process involves sending the oxidized liquid to the S2 concentration and crystallization stage. After S2 concentration and crystallization, the oxidized liquid is sent to the concentrate circulation tank 3, then via the conveying pipe 9 to the bottom of the desulfurization tower 18, and then via the conveying pipe 9 to the concentration spray layer 20. After contacting the hot flue gas from the flue gas inlet 25, it reaches the inclined plate 24 in the middle of the desulfurization tower 18, and is then sent back to the concentrate circulation tank 3 via the conveying pipe 9. This connection establishes a repetitive circulation system: the liquid returning to the concentrate circulation tank 3 is then sent back to the concentration spray layer 20 via the conveying pipe 9, contacting the hot flue gas from the flue gas inlet 25, and then reaching the inclined plate 24 in the middle of the desulfurization tower 18, and is then sent back to the concentrate circulation tank 3 via the conveying pipe 9. This concentration and circulation process is repeated until crystals appear in the concentrate. By continuously repeating the flue gas washing and concentration operations until crystals form in the concentrate circulation tank 3, and the crystal-liquid ratio is greater than 30% v / v, the concentrate containing crystals is sent to the next step, S3, for dehydration. Meanwhile, during the concentration and crystallization process, the solution in the concentrate circulation tank 3 undergoes a second degradation due to contact with the hot flue gas from the flue gas inlet 25. To ensure the crystallization effect, if it is necessary to control and adjust the crystallization environment and crystallization speed, the agitator 19 and control device 26 in the concentrate circulation tank 3 can be used to regulate the stirring speed and ammonium sulfate content range during crystallization, thereby optimizing the crystallization environment. In step S3, the concentrated liquid containing crystals is sent via the conveying pipe 9 to the vortex separator 15 in the solid-liquid separator 6 for separation. If the separation effect of the vortex separator 15 is not as expected, the intelligent filter device 14 can be used to replace the vortex separator 15 to separate the solids, which are then sent to the dryer 16 for further drying. When the nitrogen content of the separated ammonium sulfate solid is greater than 20.5% and the water content is less than 0.5%, it is conveyed to the solids collector 17. The liquid is then conveyed back to the concentrate circulation tank 3 for recycling.

[0025] Secondary purification is mainly applicable to moderately deteriorated liquids. Compared with normal liquids, moderately deteriorated liquids exhibit significant turbidity, increased suspended solids, mixed impurities and discoloration, crystal grain diameter reduced to 0.10mm-0.15mm, and significantly lower solid-liquid separation efficiency than normal slurries. They also show slight thixotropic filter cake and crystal settling velocity reduced to 1cm / min. The specific purification steps are as follows: S1 Oxidation, the same as the oxidation step in primary purification; S2 Performance Improvement, the liquid oxidized by the oxidation converter 2 is sequentially fed into the concentrate circulation tank 3 and the performance improver 4; chemical and physical reagents are added through the additive inlet 21 on the concentrate circulation tank 3 and the performance improver 4 to adjust the ammonium sulfate content to 3.00mol / L~3.85mol / L before sending it to the precipitator 5. Further, the stirrer 19 and control device 26 in the concentrate circulation tank 3 and the performance improver 4 can be used in conjunction to improve and optimize the performance of the deteriorated slurry, resulting in an improved and optimized solution. S3 Supernatant Treatment: The solution is sent to precipitator 5 for sedimentation. The bottom of precipitator 5 has an inclined plate 24 at an angle of 15-30 degrees, tilted towards the outlet. Its core function is to improve solid-liquid separation efficiency through the application of shallow pool theory, flow optimization, and enhanced separation. Simultaneously, the precipitate slides into the bottom area. The separated clarified liquid is a transparent, pale yellow solution, discharged through clarified liquid outlet 27. S4 Concentration and Crystallization: The discharged supernatant is sent to the concentrate circulation tank 3, then via conveying pipe 9 to the bottom of desulfurization tower 18, and then via conveying pipe 9 to the concentration spray layer 20. After contacting the hot flue gas from flue gas inlet 25, it reaches the inclined plate 24 in the middle of desulfurization tower 18, and is then sent back to the concentrate circulation tank 3 via conveying pipe 9. The concentration step is repeated until the concentrate crystallizes. By continuously washing the flue gas and performing concentration operations, until crystals form in the concentrate circulation tank 3, when the crystal-to-liquid ratio is greater than 30% v / v, the concentrate containing crystals is sent to the next step of desliming. S5 dehydration is performed in the same way as S3 dehydration in the primary purification stage.

[0026] Level 3 purification is mainly suitable for moderately to severely degraded liquids. Compared with normal liquids, moderately to severely degraded liquids are moderately turbid slurries, contain a large amount of suspended solids and mechanical impurities, contain a small amount of oil, have crystal grain diameters reduced to about 0.09mm-0.10mm, altered crystal shapes, are viscous and colored, easily cause clogging of operating equipment, and have very low solid-liquid separation efficiency, with crystal settling velocity reduced to about 1cm / h. The specific purification steps are as follows: S1 oxidation, which is consistent with the S1 oxidation step of Level 1 purification. S2 concentration and crystallization: The three-stage purification process eliminates the need for performance improvement and precipitation of the oxidized liquid. The oxidized liquid is sent to the concentration circulation tank 3, then via the conveying pipe 9 to the bottom of the desulfurization tower 18, and then via the conveying pipe 9 to the concentration spray layer 20. After contacting the hot flue gas from the flue gas inlet 25, it reaches the inclined plate 24 in the middle of the desulfurization tower 18, and then is sent back to the concentration circulation tank 3 via the conveying pipe 9. The concentration steps are repeated until the ammonium sulfate content of the concentrated liquid is between 3.00 mol / L and 3.85 mol / L. In the L range, the concentrated liquid is sent to the externally powered desulfurization crystallizer 7 for crystallization. When the crystal-liquid ratio is greater than 30% v / v, it proceeds to the next step, S3, for dehydration. After S3 dehydration, the concentrated liquid evaporates and crystallizes, then is sent via the conveying pipe 9 to the vortex separator 15 in the solid-liquid separator 6 for separation. If the separation effect of the vortex separator 15 is not as expected, the intelligent filter 14 can be used to replace the vortex separator 15 to separate the solids. Then, it is sent to the dryer 16 for further drying. The solids are sent to the solids container 17, and the liquid is sent to the concentrated liquid circulation tank 3 for recycling. It should be noted that the concentration and crystallization of the tertiary purification differ from the concentration and crystallization of the primary and secondary purification. The liquid after tertiary purification concentration is in the ammonium sulfate content range of 3.00 mol / L to 3.85 mol / L, and needs to be sent to the externally powered desulfurization crystallizer 7 for crystallization before being sent for dehydration. In contrast, the concentration and crystallization of the primary and secondary purification uses hot flue gas to directly concentrate the concentrated liquid to a crystal-liquid ratio greater than 30% v / v, and then sends it for dehydration.

[0027] Level IV purification is mainly applicable to severely degraded liquids. Compared with normal liquids, severely degraded liquids are highly turbid and contain a mixture of many impurities. The test slurry often contains chloride ions, fluoride ions, heavy metal ions, Prussian blue, organic matter and their reactants. The slurry is severely colored and viscous. During solid-liquid separation, the filter cake exhibits thixotropy or is impermeable. The crystal settling rate drops to about 1 cm / 12 h, and the crystal diameter shrinks to below 0.09 mm. The specific purification steps are as follows: S1 oxidation, S2 performance improvement, and S3 supernatant treatment. These three steps are consistent with the S1 oxidation, S2 performance improvement, and S3 supernatant treatment steps of Level II purification. S4 precipitate treatment: After completing the supernatant treatment, the precipitate at the bottom is discharged through the precipitate outlet 28. Furthermore, to remove the precipitate more quickly, the agitator 19 in the precipitator 5 can be activated. S5 concentration and crystallization: The supernatant discharged is sent to the concentration liquid circulation tank 3, and then to the bottom of the desulfurization tower 18 via the conveying pipe 9. It is then sent to the concentration spray layer 20 via the conveying pipe 9, and after contacting the hot flue gas from the flue gas inlet 25, it reaches the inclined plate 24 in the middle of the desulfurization tower 18. After that, it is sent back to the concentration liquid circulation tank 3 via the conveying pipe 9, and the concentration step is repeated until the ammonium sulfate content of the concentrated liquid is in the range of 3.00mol / L to 3.85mol / L. Then, the concentrated liquid is sent to the externally powered desulfurization crystallizer 7 for crystallization. When the crystal-liquid ratio is greater than 30%v / v, it enters the next step S6 dehydration. S6 deliquification involves sending the solid-liquid mixture from the externally powered desulfurization crystallizer 7 and the precipitate outlet 28 to the vortex separator 15 within the solid-liquid separator 6 for separation. If the separation effect of the vortex separator 15 is not as expected, the intelligent filter 14 can be used to replace the vortex separator 15 to separate the solids. The mixture is then sent to the dryer 16 for further drying. The solids are transported to the solids collector 18, and the liquid is transported to the concentrate circulation tank 3 for recycling. If the deliquification effect of the solid-liquid mixture at the precipitate outlet 28 is not as expected, it is directly sent to the solidification device 8 for solidification, and then sent to the solids collector 17.

[0028] The fifth-stage purification is mainly applicable to failed and deteriorated liquids. Compared with normal liquids, failed and deteriorated liquids exhibit a lack of crystalline texture to the touch, appear as creamy substances, are severely thixotropic slurries, and are ammonium sulfate emulsion slurries. Solids and liquids in these slurries cannot naturally settle and separate. The specific purification steps are as follows: S1 Oxidation, the same as the S1 oxidation in the first-stage purification. S2 Concentration: After oxidation, the oxidized liquid is sent to the concentration circulation tank 3, then via the conveying pipe 9 to the bottom of the desulfurization tower 18, and then via the conveying pipe 9 to the concentration spray layer 20. After contacting the hot flue gas from the flue gas inlet 25, it reaches the inclined plate 24 in the middle of the desulfurization tower 18, and then is sent back to the concentration circulation tank 3 via the conveying pipe 9. The concentration step is repeated until the ammonium sulfate content is in the range of 3.00 mol / L to 3.85 mol / L, at which point it enters the solidification step. S3 Solidification: The concentrated liquid is sent to the solidification device 8 via the conveying pipe 9, and the solids produced by the solidification device 8 are conveyed to the solidifier 17.

[0029] Case 1: A chemical company This chemical plant, in its ammonia-based desulfurization process, had been using lignite as boiler fuel for a long time. Lignite contains impurities such as clay minerals, carbonate minerals, and pyrite, which not only increased the ash content of the coal but also altered the characteristics of the ash slag. This resulted in more ash impurities being mixed into the boiler flue gas. After only six months of operation, the concentrated liquid in the desulfurization system became contaminated, becoming a slightly degraded liquid. It exhibited slight turbidity and a small amount of suspended solids. Testing revealed a pH of 4, an iron ion concentration of 897 mg / L, and the average diameter of the crystal grains had shrunk from the normal 0.23 mm to 0.16 mm, with the settling velocity decreasing from 10 cm / s to 1 cm / s. These changes affected the system's ammonium sulfate production efficiency, making it impossible to guarantee a daily output of 35 tons of solid ammonium sulfate. The resulting ammonium sulfate fertilizer had a yellow tint, affecting its quality, and the desulfurization system had to be operated intermittently. To address this situation, the company adopted the primary purification method described in this patented patent to solve the problem. First, the deteriorated slurry undergoes S1 oxidation treatment. During the oxidation process, the pH value of the oxidizing solution is adjusted to 5.5 and the ammonium sulfate concentration is controlled to 1.34 mol / L using the control device 26. The iron ions in the original oxidizing solution act as a catalyst for oxidation. When the oxidation rate reaches 98.5% or more, the oxidizing solution is sent to the S2 concentration and crystallization stage. When the crystal-liquid ratio after concentration and crystallization is greater than 30% v / v, the concentrated slurry containing crystals is sent to the S3 desliming stage. When the white ammonium sulfate solid produced meets the quality standards of nitrogen content greater than 20.5% and water content less than 0.5%, it is transported to the solidifier 17, and the separated liquid is transported to the concentrate circulation tank 3 for recycling.

[0030] By adopting the above-mentioned primary purification method, the desulfurization system was restored to normal operation after the deteriorated slurry was treated twice. This method effectively solved the problem of impurity accumulation caused by long-term combustion of lignite. It not only ensured the quality of ammonium sulfate, but also enabled the desulfurization system to operate continuously and stably, providing a strong guarantee for enterprise production.

[0031] Case 2: A thermal power plant This thermal power plant produces 12,781 tons of solid ammonium sulfate annually in its ammonia-based desulfurization process. Due to the co-firing of non-fossil fuels during boiler coal combustion, new impurities are introduced into the boiler flue gas, further contaminating the original flue gas in the desulfurization tower. This contaminated flue gas, upon entering the desulfurization system, carries impurities that accumulate in the desulfurization circulating liquid, continuously triggering other reactions and leading to solution deterioration. At this point, the slurry becomes noticeably turbid, containing dark brown suspended matter, with the average diameter of the crystal grains shrinking to 0.10 mm and the crystal settling velocity dropping to 1 cm / min. During separation in the ammonium sulfate solid-liquid separator 6, a slightly thixotropic filter cake forms, affecting separation and desliming efficiency, resulting in substandard ammonium sulfate quality. To address this issue, the company adopted the two-stage purification method described in this patented patent. First, the deteriorated slurry undergoes S1 oxidation treatment. The oxidized solution is then sent to the S2 purification and sedimentation stage. During the purification process, the solution is tested and found to contain 1850 mg / L of iron ions. Using control device 26 and additive inlet 21, the ammonium sulfate content is adjusted to 3.68 mol / L. Subsequently, ammonia is added to generate ferric ferric precipitate. This ferric ferric precipitate encapsulates and carries away turbid impurities, achieving performance improvement and optimization. The solution after achieving the expected performance improvement is then sent to sedimentator 5 for S3 supernatant treatment. After treatment, the clarified liquid is discharged through the clarified liquid outlet 27, and the supernatant is sent to the S4 concentration and crystallization stage. During the concentration and crystallization process, the concentrated liquid comes into contact with the flue gas and the pH value returns to normal. When the concentration step is repeated until the concentrated liquid forms crystals and the crystal-liquid ratio is greater than 30% v / v, the concentrated liquid is sent to the S3 deliquencing stage. After deliquencing, when the white ammonium sulfate solid produced meets the quality standards of nitrogen content greater than 20.5% and water content less than 0.5%, the qualified ammonium sulfate solid is sent to the solidifier 17, and the separated liquid is sent to the concentrated liquid circulation tank 3 for recycling.

[0032] By adopting the above-mentioned two-stage purification method and treating the deteriorated slurry three times, the problem caused by the co-firing of non-fossil fuels in the boiler was successfully solved. While ensuring the quality of ammonium sulfate, the company recovered 12,781 tons of ammonium sulfate products per year, creating an economic benefit of RMB 19.1715 million per year.

[0033] Case 3: A chemical company In the ammonia-based desulfurization process, this chemical plant encountered a problem: sludge was co-fired during boiler coal combustion, contaminating the concentrated liquid in the desulfurization system. The contaminated liquid exhibited a high concentration of suspended solids, turbidity, and contained organic and mechanical impurities. The slurry became viscous and pale yellow, the ammonium sulfate crystals became smaller, their crystal shape changed, the average crystal diameter shrank to 0.09 mm, and the crystal settling velocity decreased to 1 cm / h. These problems subsequently led to material buildup and blockage within the desulfurization equipment, resulting in a material imbalance in the desulfurization system. To address this issue, the company adopted the three-stage purification method described in this patented patent. First, the deteriorated slurry undergoes S1 oxidation treatment, followed by S2 concentration and crystallization. When the ammonium sulfate content after concentration is controlled at 3.68 mol / L, it is then sent to the concentration and crystallization stage. Crystallization is carried out using an externally powered desulfurization crystallizer 7. When the crystal-liquid ratio is greater than 30% v / v and the ammonium sulfate crystal particles further increase in size, the concentrated liquid containing crystals is sent to the S3 desliming stage. When the diameter of the white ammonium sulfate solid crystals produced is greater than 0.23 mm, the nitrogen content is greater than 20.5%, and the water content is less than 0.5%, it is transported to the solidifier 17, and the separated liquid is transported to the concentrate circulation tank 3 for recycling.

[0034] By adopting the above-mentioned three-stage purification method, the deteriorated slurry was treated three times, which restored the concentrated liquid to normal operation and solved the problems caused by boiler sludge co-firing. While ensuring the quality of ammonium sulfate, the average crystal diameter increased from the original 0.09mm to 0.23mm, thus recovering the economic losses caused to the enterprise by boiler sludge co-firing.

[0035] Case 4: A coking company During the ammonia-based desulfurization process, the company produces 110 tons of solid ammonium sulfate daily. Due to the co-firing of waste into the boiler coal, impurities are introduced into the desulfurization system through the flue gas, causing the concentrate to become highly turbid and mixed with many impurities. Tests showed that the concentrate contained 97,869 mg / L of chloride ions, 1,750 mg / L of iron ions, and 19-22% (mass fraction) of Prussian blue in insoluble matter. Simultaneously, the concentrate contained suspended solids, oil, and light-density organic matter, resulting in increased viscosity, increased flow resistance, decreased mass transfer rate, and difficulty in ammonium sulfate molecule diffusion. During separation, the filter cake exhibited impermeability, the crystal settling rate dropped to 1 cm / 12 h, and it was difficult to uniformly distribute and form stable crystals. This even led to the inability of ammonium sulfate to crystallize during operation, deterioration of the concentrate quality, and a grayish-blue tint. Furthermore, it altered the effective supersaturation of the ammonium sulfate solution, among other problems. To address this situation, the company adopted the four-stage purification method of this patented patent. First, the deteriorated slurry undergoes S1 oxidation treatment, followed by S2 purification and precipitation treatment. During the purification process, the ammonium sulfate content is adjusted to 3.68 mol / L. Alkaline substances and silica are added to the additive inlet 21 of the performance improver 4, generating insoluble metal hydroxide precipitates and silica coated with ammonium sulfate. The performance improver liquid is then sent to the precipitator 5 through the conveying pipe 9 for precipitation. Under gravity, the supernatant and precipitate are separated. Next, S3 supernatant treatment and S4 precipitate treatment are carried out, followed by S4 concentration and crystallization and S5 desliming steps. When the nitrogen content of solid ammonium sulfate is greater than 20.5% and the water content is less than 0.5%, the qualified ammonium sulfate is sent to the solidifier 17, and the separated liquid is sent to the concentrate circulation tank 3 for recycling.

[0036] By adopting the above-mentioned four-stage purification method, the desulfurization system was restored to normal operation after the deteriorated slurry was treated three times. This successfully solved the problem of severely deteriorated liquid caused by the co-firing of waste from the boiler coal. While ensuring the quality of ammonium sulfate, it gradually reduced impurities such as iron ions, chloride ions and Prussian blue, saving the company 110 tons of ammonium sulfate products per day and creating an economic benefit of 165,000 yuan per day.

[0037] Case 5: A steel company During the ammonia-based desulfurization process at this steel company, the dust removal efficiency at the front end of the desulfurization tower decreased. After six months of continuous operation, the complex impurities in the iron ore itself, coupled with the fact that ammonia-based desulfurization is a closed-loop system with no wastewater discharge during operation, led to a series of serious problems in the concentrate: the cumulative chloride ion concentration increased to 134,230 mg / L, suspended solids reached 3,320 mg / L, calcium ion content was 538 mg / L, and iron ion content was 2,536 mg / L. The concentrate also contained amorphous blackish-red fine powder that was insoluble in water. This prevented the solid and liquid from naturally settling and separating during the crystallization of the concentrate. The concentrate had no crystalline texture to the touch and appeared as a black emulsion, forming a degraded and ineffective liquid. This forced the production of ammonium sulfate fertilizer to stop, seriously endangering the stable operation of the desulfurization system. At the same time, the impeller of the slurry circulation pump and the ammonium sulfate production equipment suffered severe corrosion, reducing their service life to only 3-6 months. In response to the aforementioned severe situation, the company adopted the five-stage purification method of this patent to solve the problem: First, the deteriorated slurry undergoes S1 oxidation treatment; the oxidized liquid is then sent to the S2 concentration stage. When the ammonium sulfate content after concentration is controlled at 3.68 mol / L, the concentrated liquid is directly directed to the solidification step; in S3 solidification, the concentrated liquid is sent to the solidification device 8 through the conveying pipe 9, and the solid produced after processing by the solidification device 8 is directly conveyed to the solidifier 17.

[0038] Through repeated application of the patented five-stage purification method, a total of 2119m³ of the failed and deteriorated liquid was replaced. 3 The process continues until the concentrated solution can crystallize normally to form ammonium sulfate, and the desulfurization system resumes stable operation. This simultaneously solves the corrosion problem of the desulfurization equipment and the ammonium sulfate equipment, effectively guaranteeing the company's environmental and economic benefits.

[0039] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made to it in form and detail without departing from the scope defined by the claims of the present invention.

Claims

1. A purification device for deteriorated slurry in ammonia desulfurization, characterized in that: The purification device includes, in sequence, an absorption spray liquid storage tank (1), an oxidation converter (2), a concentrate circulation tank (3), a performance improver (4), and a precipitator (5); the absorption spray liquid storage tank (1) is connected to the absorption spray layer (22) and the absorption receiving tray (23); the concentrate circulation tank (3) is connected to the externally powered desulfurization crystallizer (7), the solidification device (8), the precipitator (5), and the solid-liquid separator (6); the concentrate circulation tank (3) is also connected to the bottom of the desulfurization tower (18) and the inclined plate in the middle of the desulfurization tower (18). 24) Connection; The outlet of the precipitator (5) is provided with a clarified liquid outlet (27) and a precipitate outlet (28). The clarified liquid outlet (27) is connected to the concentrated liquid circulation tank (3) and the externally powered desulfurization crystallizer (7) respectively. The precipitate outlet (28) is connected to the solid-liquid separator (6) and the solidification device (8) respectively. The externally powered desulfurization crystallizer (7) is connected to the solid-liquid separator (6). The solid-liquid separator (6) and the solidification device (8) are both connected to the solidifier (17). The concentrated liquid circulation tank (3) and the performance improver (4) are provided with an additive inlet (21).

2. The purification device for deteriorated slurry in ammonia desulfurization according to claim 1, characterized in that: The oxidation converter (2) is equipped with an oxidation power tank (10) with a built-in aerator (11). One end of the oxidation power tank (10) is connected to the absorption spray liquid storage tank (1), and the other end is connected to the concentrate circulation tank (3). The aerator (11) is connected to the oxidation wind power source (13) through the air duct (12).

3. A purification device for deteriorated slurry in ammonia desulfurization according to any one of claims 1 or 2, characterized in that: The solid-liquid separator (6) includes a smart filter (14), a vortex separator (15), and a dryer (16). The smart filter (14) and the vortex separator (15) are connected to the externally powered desulfurization crystallizer (7), the concentrate circulation tank (3), and the precipitate outlet (28) through the conveying pipe (9), respectively. The smart filter (14) and the vortex separator (15) are then connected to the dryer (16) through the conveying pipe (9), and the dryer (16) is connected to the solidifier (17).

4. A purification device for deteriorated slurry in ammonia desulfurization according to any one of claims 1-3, characterized in that: The concentrated liquid circulation tank (3), performance improver (4), and precipitator (5) are equipped with a stirrer (19); the absorbent spray liquid storage tank (1), oxidation converter (2), concentrated liquid circulation tank (3), performance improver (4), and precipitator (5) are equipped with a control device (26); the bottom of the precipitator (5) is provided with an inclined plate (24) that slopes towards the outlet end.

5. A purification method for a purification device for deteriorated slurry in ammonia desulfurization as described in any one of claims 1-4, characterized in that: The purification methods described include primary purification, secondary purification, tertiary purification, quaternary purification, or quinary purification.

6. The purification method according to claim 5, characterized in that: The primary purification process includes the following steps: S1 Oxidation: The deteriorated slurry from the ammonia desulfurization process, which comes from the absorption receiving pan (23), is sent to the absorption spray liquid storage tank (1) and then to the oxidation converter (2) for oxidation. S2 Concentration and Crystallization: The oxidized liquid is sent to the concentrate circulation tank (3) and then sequentially to the bottom of the desulfurization tower (18) and the concentration spray layer (20). After contacting the hot flue gas from the flue gas inlet (25), it is sent to the inclined plate (24) in the middle of the desulfurization tower (18) and returned to the concentrate circulation tank (3). The concentration steps are repeated until crystals are formed. When the crystal-liquid ratio is greater than 30% v / v, the concentrate with crystals is sent to the next step of deliquescence. S3 Deliquescence: The slurry containing solids after concentration and crystallization is sent to the solid-liquid separator (6). The solids are sent to the solid feeder (17), and the liquid is sent to the concentrate circulation tank (3) for recycling.

7. The purification method according to claim 5, characterized in that: The secondary purification process includes the following steps: S1 Oxidation, the same as the oxidation steps of the first-stage purification; S2 Performance Improvement, the oxidized liquid is sequentially sent to the concentrate circulation tank (3) and the performance improver (4) for performance improvement; S3 Supernatant Treatment, the improved solution is sent to the precipitator (5) for precipitation, and the separated supernatant is discharged through the clarified liquid outlet (27); S4 Concentration and Crystallization: The discharged supernatant is sent to the concentrate circulation tank (3) and then sequentially transported to the bottom of the desulfurization tower (18) and the concentration spray layer (20). After contacting the hot flue gas from the flue gas inlet (25), it reaches the inclined plate (24) in the middle of the desulfurization tower (18) and is then sent back to the concentrate circulation tank (3). The concentration step is repeated until the concentrate crystallizes. When the crystal-liquid ratio is greater than 30% v / v, the concentrate with crystals is sent to the next step of dehydration. S5 Dehydration: This step is consistent with the S3 dehydration step in the primary purification.

8. The purification method according to claim 5, characterized in that: The three-stage purification process includes the following steps: S1 Oxidation: This step is consistent with the S1 oxidation step of the first-stage purification. S2 Concentration and Crystallization: The oxidized liquid is sent to the concentration liquid circulation tank (3) and sequentially sent to the bottom of the desulfurization tower (18) and the concentration spray layer (20). After contacting the hot flue gas from the flue gas inlet (25), it reaches the inclined plate (24) in the middle of the desulfurization tower (18) and is then sent back to the concentration liquid circulation tank (3). The concentration step is repeated until the ammonium sulfate content of the concentrated liquid is between 3.00 mol / L and 3.85 mol / L. The concentrated liquid is then sent to the externally powered desulfurization crystallizer (7) for crystallization. When the crystal-liquid ratio is greater than 30% v / v, it enters the next step, S3 Dehydration. S3 Dehydration: The slurry containing solids after concentration and crystallization is sent to the solid-liquid separator (6). The solids are sent to the solid feeder (17), and the liquid is sent to the concentration liquid circulation tank (3) for recycling.

9. A purification method according to claim 5, characterized in that: The aforementioned four-level purification includes the following steps: The three steps of S1 oxidation, S2 performance improvement, and S3 supernatant treatment are the same as those of the secondary purification process. S4 precipitate treatment: After supernatant treatment, the precipitate at the bottom is discharged through the precipitate outlet (28). S5 concentration and crystallization: The discharged supernatant is sent to the concentration circulation tank (3), and then sequentially transported to the bottom of the desulfurization tower (18) and the concentration spray layer (20). After contacting the hot flue gas from the flue gas inlet (25), it reaches the inclined plate (24) in the middle of the desulfurization tower (18). Then, it is sent back to the concentrate circulation tank (3) and the concentration step is repeated until the concentration of ammonium sulfate in the liquid is 3.00mol / L to 3.85mol / L. The concentrate is then sent to the externally powered desulfurization crystallizer (7) for crystallization. When the crystal-liquid ratio is greater than 30%v / v, it enters the next step S6 deliquescence. In S6 deliquescence, the solid-liquid mixture from the externally powered desulfurization crystallizer (7) and the precipitate outlet (28) is sent to the solid-liquid separator (6) for separation. The solid is sent to the solid feeder (17) and the liquid is sent to the concentrate circulation tank (3) for recycling.

10. A purification method according to claim 5, characterized in that: The five-stage purification process includes the following steps: S1 Oxidation is the same as S1 Oxidation in the first stage of purification; S2 Concentration: after oxidation, the oxidizing liquid is sent to the concentration liquid circulation tank (3), and then sent to the bottom of the desulfurization tower (18) and the concentration spray layer (20) in sequence. After contacting the hot flue gas from the flue gas inlet (25), it reaches the inclined plate (24) in the middle of the desulfurization tower (18), and then is sent back to the concentration liquid circulation tank (3) to repeat the concentration step. The ammonium sulfate content is 3.00mol / L to 3.85mol / L, and then enters the solidification step; S3 Solidification: the concentrated liquid is sent to the solidification device (8), and the solid produced by the solidification device (8) is transported to the solidifier (17).

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