Spent sulfuric acid evaporation concentration and fluorine chlorine stripping device

Abstract

A waste sulfuric acid evaporation concentration and fluorine chlorine stripping device, including reaction impurity removal system, evaporation concentration system, high temperature stripping system, tail gas treatment system, sealing water system, reaction impurity removal system first pretreatment of fluorine chlorine containing waste sulfuric acid, remove arsenic and other metal ions in waste acid, evaporation concentration system to the impurity containing fluorine chlorine waste sulfuric acid is concentrated, concentrated liquid into high temperature stripping system, high temperature stripping system will dissolve in liquid fluorine chlorine acid stripping to gaseous, realize the separation of sulfuric acid and fluorine chlorine, the liquid sulfuric acid which cannot be stripped out is the final product; Stripped fluorine chlorine mixed acid gas is treated by lime milk neutralization, generating calcium fluoride precipitate and calcium chloride solution, calcium fluoride is obtained after solid-liquid separation by filter press, and the calcium chloride solution can be treated again.

Description

Technical Field

[0001] This utility model belongs to the field of concentrated and recycled production technology of fluorine-containing chlorine waste sulfuric acid, specifically involving a waste sulfuric acid evaporation and concentration and fluorine-chlorine stripping device. Background Technology

[0002] In response to the environmental protection requirements of low-carbon, environmentally friendly, and resource-based production, modern enterprises have abandoned traditional neutralization and other high-cost treatment methods for waste sulfuric acid generated in the phosphoric acid industry and other industrial production processes. They are actively exploring more environmentally and economically efficient resource recycling solutions to recycle and utilize waste acid, turning waste into treasure and bringing considerable economic benefits to enterprises. Although there are many feasible solutions for the treatment of waste sulfuric acid in the industry, these traditional treatment methods still have many shortcomings.

[0003] Early technologies often employed evaporation concentration or high-temperature pyrolysis to treat fluorine-containing waste acid. However, these methods generally suffer from incomplete fluorine recovery, unusable byproducts, high energy consumption, and stringent equipment material requirements, leading to increased production risks. Waste sulfuric acid generated in phosphoric acid production often contains fluorides (such as fluorosilicic acid), chloride ions, phosphoric acid, and heavy metals. During high-temperature pyrolysis, fluorides can be converted into corrosive substances such as pyrophosphoric acid and metaphosphoric acid, increasing the risk of equipment (such as waste heat boiler tube bundles) rupture; chloride ions exacerbate corrosion and interfere with resource recovery.

[0004] Precipitation and Adsorption: For high-concentration fluoride wastewater, traditional precipitation methods have drawbacks such as large equipment size, difficulty in achieving effluent standards, and difficulty in sediment settling; adsorption methods, due to the limited capacity of adsorbents, are only suitable for small-volume water treatment and cannot meet the needs of large-scale industrial applications.

[0005] Current fluoride and chlorine removal technologies have the following shortcomings:

[0006] 1. Low efficiency of physicochemical defluorination and chlorine removal: Existing methods such as thorium salt defluorination, ion exchange, and silver chloride precipitation generally suffer from high investment costs or low removal rates. For example, ion exchange has insufficient selectivity for fluoride and chlorine, while precipitation is easily interfered with by other ions, resulting in unstable defluorination and chlorine removal effects.

[0007] 2. High difficulty in resource recovery: The coexistence of fluorine, chlorine, and sulfate ions in fluorine- and chlorine-containing waste sulfuric acid exacerbates the difficulty of separation. Traditional processes are difficult to recover sulfuric acid and fluorine- and chlorine resources simultaneously, often requiring multi-stage treatment, which is complex and energy-intensive.

[0008] 3. Equipment Corrosion and Maintenance Challenges

[0009] High corrosiveness leads to equipment wear and tear: Concentrated sulfuric acid is highly corrosive, especially under high-temperature conditions, placing extremely high demands on the materials used in evaporation and concentration equipment. Existing equipment (such as graphite heat exchangers and stainless steel materials) is prone to corrosion during long-term operation, significantly increasing maintenance costs.

[0010] Exploration of emerging technologies

[0011] Combining electrodialysis with membrane separation: Recent studies have attempted to use electrodialysis to selectively separate acids and fluorides and chlorines, and then combine this with falling membrane evaporation to achieve sulfuric acid concentration. However, this technology has extremely high requirements for the corrosion resistance and selectivity of the membrane material and has not yet been widely used.

[0012] In summary, the concentration and recovery of fluorine- and chlorine-containing waste sulfuric acid faces three major challenges: low efficiency in multi-component separation, severe equipment corrosion, and insufficient resource utilization rate. There is an urgent need to develop efficient, economical, and stable integrated technologies to achieve the simultaneous recovery of sulfuric acid and fluorine and chlorine. Summary of the Invention

[0013] The technical problem to be solved by this utility model is to overcome the shortcomings of the prior art and provide a waste sulfuric acid evaporation and concentration and fluorine and chlorine stripping device, which realizes the stability and reliability of production, enables the effective recycling of resources, avoids resource waste, improves economic efficiency, and reduces wastewater discharge and environmental pollution.

[0014] The technical solution adopted to solve the above technical problems is: a waste sulfuric acid evaporation and concentration and fluorine and chlorine stripping device, including a reaction and impurity removal system, an evaporation and concentration system, a high temperature stripping system, a tail gas treatment system, and a sealing water system;

[0015] The aforementioned reaction purification system is as follows: Sodium hydrosulfide from the outside enters a sodium hydrosulfide solution preparation tank. The lower part of the sodium hydrosulfide solution preparation tank is connected to the upper inlet of a hydrogen sulfide absorber via a sodium hydrosulfide solution pump installed on a pipeline. Fluorine-free sulfuric acid solution from the outside enters a hydrogen sulfide generator. The lower outlet of the hydrogen sulfide generator is connected to a sodium sulfate solution storage tank via a sodium sulfate solution discharge pump installed on a pipeline. The upper outlet of the hydrogen sulfide generator is connected in two ways: one to the inlet of a hydrogen sulfide scrubbing tower, and the other to the first and second injectors. The bottom of the hydrogen sulfide scrubbing tower is connected to a hydrogen sulfide tail gas absorption tank. The hydrogen sulfide tail gas absorption tank is connected in two ways: one to the hydrogen sulfide scrubbing tower via a hydrogen sulfide absorption liquid pump installed on a pipeline, and the other... The system is connected to a sodium hydrogen sulfide solution preparation tank. The outlet of the first injector is connected to the first heavy metal remover, and the outlet of the second injector is connected to the second heavy metal remover. The first heavy metal remover is connected to the first injector via a jet circulation pump installed on a pipeline. The second heavy metal remover is connected to the second injector via a jet circulation pump installed on a pipeline. The waste sulfuric acid tank is connected to the first and second heavy metal removers via a waste sulfuric acid pump installed on a pipeline. The second heavy metal remover is connected to a waste sulfuric acid filter press pump installed on a pipeline. The outlet of the waste sulfuric acid filter press is connected to a waste sulfuric acid storage tank. The waste sulfuric acid storage tank is connected to an evaporation and concentration system via a sulfuric acid evaporation feed pump installed on a pipeline.

[0016] The evaporation and concentration system is as follows: Sulfuric acid solution pumped in by the sulfuric acid evaporation feed pump enters the preheater. The outlet of the preheater is connected to the inlet of the triple-effect evaporator via a triple-effect evaporation circulation pump installed on a pipeline. The outlet of the triple-effect evaporator is connected to the triple-effect separator. The top outlet of the triple-effect separator is connected to the preheater, the first condenser, and the second condenser. Cooling water from the cooling tower sequentially enters the second condenser and the first condenser, then returns to the cooling tower by a circulating cooling water pump. Cooling water from the cooling tower enters the third condenser and returns to the cooling tower by a circulating cooling water pump. The lower outlets of the first and second condensers are connected to the top inlet of the third condenser. The concentrated material in the triple-effect separator passes through the second effect... The feed pump enters the second-effect evaporator. The outlet of the second-effect evaporator is connected to the second-effect separator. The top outlet of the second-effect separator is connected to the third-effect evaporator through the second saturator, and the bottom outlet is connected to the second-effect evaporator through the second-effect evaporation circulation pump installed on the pipeline. The concentrated material in the second-effect separator enters the first-effect evaporator through the first-effect feed pump installed on the pipeline. The outlet of the first-effect evaporator is connected to the inlet of the first-effect separator. The top outlet of the first-effect separator is connected to the inlet of the second-effect evaporator through the first saturator, and the bottom outlet is connected to the first-effect evaporation circulation pump installed on the pipeline. The concentrated material in the first-effect separator enters the high-temperature stripping system.

[0017] The condensate from the double-effect evaporator enters the first-effect evaporator condensate tank and is then pumped into the evaporator condensate storage tank by the first-effect evaporator condensate pump. The steam condensate from the first-effect evaporator enters the steam condensate tank and is then pumped into the boiler by the steam condensate pump. The condensate and non-condensable gas produced by the triple-effect evaporator, preheater, first condenser, second condenser, and third condenser enter the triple-effect evaporator condensate tank 36. The non-condensable gas at the top of the triple-effect evaporator condensate tank enters the vacuum unit. The bottom of the triple-effect evaporator condensate tank is connected to the evaporator condensate tank via a triple-effect evaporator condensate pump installed on a pipeline, and another path is sent to the first saturator, second saturator, and third saturator via a saturation pump.

[0018] The high-temperature stripping system is as follows: the concentrated material in the first-effect separator enters the fluorine-chlorine stripping heater through a fluorine-chlorine stripping heating pump. The lower outlet of the fluorine-chlorine stripping heater is connected to a steam condensate tank, and the top outlet is connected to the fluorine-chlorine stripping tower. The lower outlet of the fluorine-chlorine stripping tower is connected to the upper inlet of the fluorine-chlorine stripping tower through a fluorine-chlorine stripping circulation pump installed on the pipeline, and the other is connected to a concentrated sulfuric acid cooler. The cooled water from the cooling tower enters the concentrated sulfuric acid cooler and is then returned to the cooling tower by a circulating cooling water pump. The concentrated sulfuric acid in the concentrated sulfuric acid cooler is connected to a sulfuric acid storage tank. The top outlet of the fluorine-chlorine stripping tower is connected to the fluorine-chlorine stripping condenser through a third saturator. The bottom outlet of the fluorine-chlorine stripping condenser is connected to a fluorine-chlorine stripping condensate tank. The fluorine-chlorine stripping condensate tank is connected to an evaporation condensate tank through a fluorine-chlorine stripping condensate pump installed on the pipeline. The cooled water from the cooling tower enters the fluorine-chlorine stripping condenser and is then returned to the cooling tower by a circulating cooling water pump.

[0019] The exhaust gas treatment system is as follows: exhaust gas from the vacuum unit and other equipment outlets is collected through pipelines and then first fed into a primary absorption tower. The top outlet of the primary absorption tower is connected to a secondary absorption tower. The lower outlet of the primary absorption tower is connected via two paths: one path to the primary absorption tower circulating pump installed on a pipeline and connected to the primary absorption tower cooler; and another path to the calcium fluoride filter press installed on a pipeline and connected to the calcium fluoride filter press. The outlet of the calcium fluoride filter press is connected via two paths: one path to a calcium chloride liquid tank and the other path to the primary absorption tower. The calcium chloride liquid tank is connected via a calcium chloride... The calcium solution pump is connected to the calcium chloride solution storage tank. The primary absorption tower cooler is connected to the upper inlet of the primary absorption tower. The cooled water from the cooling tower enters the primary absorption tower cooler and is then returned to the cooling tower by the circulating cooling water pump. The exhaust gas from the top outlet of the secondary absorption tower is discharged through an induced draft fan installed on the pipeline. The lower outlet of the secondary absorption tower is connected to the upper inlet of the secondary absorption tower and the lower inlet of the primary absorption tower through a secondary absorption tower circulating pump installed on the pipeline. The calcium chloride hydrochloride solution preparation tank is connected to the secondary absorption tower through a calcium chloride hydrochloride solution pump installed on the pipeline.

[0020] The sealing water system is as follows: after the cooling water from the cooling tower enters the sealing water tank, it is returned to the cooling tower by the circulating cooling water pump. All the sealing water pumped out flows into the sealing water tank, and after being cooled by the circulating cooling water through the coils in the sealing water tank, it enters each pump that needs sealing water.

[0021] The first and second heavy metal removers of this invention are supplied with ozone by an ozone generator.

[0022] The fluorine-chlorine stripping tower of this invention is heated by an air heater, and the gas in the air heater comes from compressed air from an air compressor station.

[0023] The hydrogen sulfide generator, first heavy metal remover, second heavy metal remover, fluorine and chlorine stripping heater, single-effect evaporator, and fluorine and chlorine stripping tower of this invention are heated by external live steam.

[0024] In this invention, the waste sulfuric acid tank, sodium hydrogen sulfide solution preparation tank, hydrogen sulfide scrubbing tower, waste sulfuric acid storage tank for removing impurities, vacuum unit, sealed water tank, calcium fluoride filter press, and non-condensable gas generated by the impurity removal plate and frame filter press enter the calcium hydroxide solution preparation tank in one direction and enter the primary absorption tower in the other direction.

[0025] This utility model includes a sodium hydrogen sulfide solution preparation tank, a hydrogen sulfide generator, a hydrogen sulfide tail gas absorption tank, a first heavy metal remover, a second heavy metal remover, a waste sulfuric acid storage tank, a first-effect separator, a third-effect separator, a vacuum unit, a calcium chloride solution preparation tank, a calcium chloride solution tank, a first-stage absorption tower, a second-stage absorption tower, a sealed water tank, a cooling water tower pool, a second-effect separator, and a fluoride-chlorine stripping tower through which process water is introduced.

[0026] This invention has the following advantages over the prior art:

[0027] 1. The device adopts a process route that combines reaction purification, evaporation concentration and high-temperature stripping to treat the waste acid. The process is mature, stable, simple to operate, with reasonable operating costs and low overall investment.

[0028] 2. The heavy metal remover ensures thorough material reaction and uses alkaline solution for the absorption of harmful excess tail gas, avoiding the risk of leakage. A closed-loop pump-sealed water circulation system is installed to reduce waste of primary water and improve the operating environment. The evaporation and concentration system employs multi-effect evaporation and concentration, increasing the total heat transfer temperature difference, improving heat utilization, and ensuring reasonable investment. The counter-current feeding method for evaporation and concentration is consistent with the material properties and minimizes heat loss.

[0029] 3. Install a secondary steam saturator to increase the heat transfer coefficient of the secondary steam; use the secondary steam to preheat the system feed, making comprehensive use of heat and saving energy and reducing consumption.

[0030] 4. The high-temperature stripping system adopts a process combining evaporation concentration and stripping, which has high heat utilization, thorough stripping, high operability, and a reasonable and advanced process. The high-temperature stripping system can also use high-temperature compressed air or air for stripping, which is more energy-efficient when the output and stripping requirements are not high. The fluorinated chlorine stripping system has multiple operating modes to meet the usage requirements of different working conditions. Attached Figure Description

[0031] Figures 1-3 This is a schematic diagram of the structure of this utility model.

[0032] In the diagram: 1. Waste sulfuric acid tank; 2. Waste sulfuric acid pump; 3. Sodium hydrogen sulfide solution preparation tank; 4. Sodium hydrogen sulfide solution pump; 5. Hydrogen sulfide generator; 6. Sodium sulfate solution discharge pump; 7. Hydrogen sulfide scrubbing tower; 8. Hydrogen sulfide tail gas absorption tank; 9. Hydrogen sulfide absorption liquid pump; 10. Ozone generator; 11. First heavy metal removal unit; 12. Jet circulation pump; 13. Second heavy metal removal unit; 14. Waste sulfuric acid filter press pump; 15. Impurity-removed waste sulfuric acid storage tank; 16. 17. Sulfuric acid evaporation feed pump; 18. Concentrated sulfuric acid cooler; 19. Fluorine-chlorine stripping circulation pump; 20. Fluorine-chlorine stripping heating pump; 21. Fluorine-chlorine stripping heater; 22. Steam condensate pump; 23. Steam condensate tank; 24. Single-effect evaporator; 25. Single-effect evaporation circulation pump; 26. Single-effect evaporation condensate pump; 27. Single-effect evaporation condensate tank; 28. Single-effect feed pump; 29. ​​Double-effect evaporation circulation pump; 30. Double-effect evaporator; 31. Double-effect feed pump; 32. Triple-effect evaporator; 33. Triple-effect evaporator circulation pump; 34. Triple-effect separator; 35. Preheater; 36. Triple-effect evaporator condensate tank; 37. Triple-effect evaporator condensate pump; 38. First condenser; 39. Second condenser; 40. Saturated water pump; 41. Third condenser; 42. Fluorine and chlorine stripping condensate tank; 43. Fluorine and chlorine stripping condensate pump; 44. Fluorine and chlorine stripping condenser; 45. Vacuum unit; 46. Calcium hydroxide solution preparation tank; 47. Calcium hydroxide solution pump; 48. Calcium chloride solution pump; 49. Calcium chloride solution tank; 50. Fluoride 51. Calcium filter press pump; 52. Primary absorption tower; 53. Primary absorption tower circulating pump; 54. Primary absorption tower cooler; 55. Secondary absorption tower; 56. Secondary absorption tower circulating pump; 57. Exhaust fan; 58. Sealed water tank; 59. Sealed water pump; 60. Circulating cooling water pump; 61. Cooling tower; 62. Calcium fluoride filter press; 63. Secondary saturator; 64. Double-effect separator; 65. Primary saturator; 66. Fluorine and chlorine stripping tower; 67. Air heater; 68. Impurity removal plate and frame filter press; 69. Secondary ejector; 70. Primary ejector; 71. Tertiary saturator. Detailed Implementation

[0033] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments, but the present invention is not limited to these embodiments.

[0034] Example 1

[0035] exist Figures 1-3 The present invention relates to a waste sulfuric acid evaporation and concentration and fluorine and chlorine stripping device, which includes a reaction and impurity removal system, an evaporation and concentration system, a high-temperature stripping system, a tail gas treatment system, and a sealing water system.

[0036] The aforementioned reaction purification system is as follows: Sodium hydrosulfide from the outside enters the sodium hydrosulfide solution preparation tank 3. The lower part of the sodium hydrosulfide solution preparation tank 3 is connected to the upper inlet of the hydrogen sulfide absorber 5 via a sodium hydrosulfide solution pump 4 installed on a pipeline. Fluorine-free sulfuric acid solution from the outside enters the hydrogen sulfide generator 5. The lower outlet of the hydrogen sulfide generator 5 is connected to the sodium sulfate solution storage tank via a sodium sulfate solution discharge pump 6 installed on a pipeline. The upper outlet of the hydrogen sulfide generator 5 is connected in one direction to the inlet of the hydrogen sulfide scrubbing tower 7 and in another direction to the first ejector 69 and the second ejector 68. The bottom of the hydrogen sulfide scrubbing tower 7 is connected to the hydrogen sulfide tail gas absorption tank 8. The hydrogen sulfide tail gas absorption tank 8 is connected in one direction to the hydrogen sulfide scrubbing tower 7 and in another direction to the sodium hydrosulfide solution preparation tank 3 via a hydrogen sulfide absorption liquid pump 9 installed on a pipeline. The outlet of the first ejector 69 is connected to the first heavy metal... The first heavy metal remover 11 is connected to the first heavy metal remover 69 via the jet circulation pump 12 installed on the pipeline, and the second heavy metal remover 13 is connected to the second jet 68 via the jet circulation pump 12 installed on the pipeline. The waste sulfuric acid tank 1 is connected to the first heavy metal remover 11 and the second heavy metal remover 13 via the waste sulfuric acid pump 2 installed on the pipeline. The second heavy metal remover 13 is connected to the impurity removal plate and frame filter press 67 via the waste sulfuric acid filter press 14 installed on the pipeline. The outlet of the impurity removal plate and frame filter press 67 is connected to the impurity removal waste sulfuric acid storage tank 15. The impurity removal waste sulfuric acid storage tank 15 is connected to the evaporation and concentration system via the sulfuric acid evaporation feed pump 16 installed on the pipeline. In this embodiment, the first heavy metal remover 11 and the second heavy metal remover 13 are supplied with ozone by the ozone generator 10.

[0037] The evaporation and concentration system is as follows: Sulfuric acid solution pumped in by sulfuric acid evaporation feed pump 16 enters preheater 35. The outlet of preheater 35 is connected to the inlet of triple-effect evaporator 32 via a triple-effect evaporation circulation pump 33 installed on a pipeline. The outlet of triple-effect evaporator 32 is connected to triple-effect separator 34. The top outlet of triple-effect separator 34 is connected to preheater 35, first condenser 38, and second condenser 39. Cooling water from cooling tower 60 sequentially enters second condenser 39 and first condenser 38, then returns to cooling tower 60 by circulating cooling water pump 59. Cooling water from cooling tower 60 enters third condenser 41, then returns to cooling tower 60 by circulating cooling water pump 59. The lower outlets of first condenser 38 and second condenser 39 are connected to the top inlet of third condenser 41. The concentrated material in triple-effect separator 34... The material enters the second-effect evaporator 30 through the second-effect feed pump 31. The outlet of the second-effect evaporator 30 is connected to the second-effect separator 63. The top outlet of the second-effect separator 63 is connected to the third-effect evaporator 32 through the second saturator 62, and the bottom outlet is connected to the second-effect evaporator 30 through the second-effect evaporation circulation pump 29 installed on the pipeline. The concentrated material in the second-effect separator 63 enters the first-effect evaporator 23 through the first-effect feed pump 28 installed on the pipeline. The outlet of the first-effect evaporator 23 is connected to the inlet of the first-effect separator 24. The top outlet of the first-effect separator 24 is connected to the inlet of the second-effect evaporator 30 through the first saturator 64, and the bottom outlet is connected to the first-effect evaporation circulation pump 25 installed on the pipeline. The concentrated material in the first-effect separator 24 enters the high-temperature stripping system.

[0038] The condensate from the double-effect evaporator 30 enters the first-effect evaporative condensate tank 27 and is then pumped into the evaporative condensate storage tank by the first-effect evaporative condensate pump 26. The steam condensate from the first-effect evaporator 23 enters the steam condensate tank 22 and is then pumped into the boiler by the steam condensate pump 21. The condensate and non-condensable gas produced by the triple-effect evaporator 32, preheater 35, first condenser 38, second condenser 39, and third condenser 41 enter the triple-effect evaporative condensate tank 36. The non-condensable gas at the top of the triple-effect evaporative condensate tank 36 enters the vacuum unit 45. The bottom of the triple-effect evaporative condensate tank 36 is connected to the evaporative condensate tank via a triple-effect evaporative condensate pump 37 installed on a pipeline, and the other path enters the first saturator 64, the second saturator 63, and the third saturator 70 via a saturation pump 40.

[0039] The high-temperature stripping system is as follows: the concentrated material in the first-effect separator 24 enters the fluorine-chlorine stripping heater 20 through the fluorine-chlorine stripping heating pump 19. The lower outlet of the fluorine-chlorine stripping heater 20 is connected to the steam condensate tank 22, and the top outlet is connected to the fluorine-chlorine stripping tower 65. The lower outlet of the fluorine-chlorine stripping tower 65 is connected to the upper inlet of the fluorine-chlorine stripping tower 65 through a fluorine-chlorine stripping circulation pump 18 installed on the pipeline, and the other path is connected to the concentrated sulfuric acid cooler 17. The cooled water from the cooling tower 60 enters the concentrated sulfuric acid cooler 17 and is then returned to the cooling tower 60 by the circulating cooling water pump 59. The concentrated sulfuric acid is connected to the sulfuric acid storage tank; the top outlet of the fluorine-chlorine stripping tower 65 is connected to the fluorine-chlorine stripping condenser 44 through the third saturator 70, and the bottom outlet of the fluorine-chlorine stripping condenser 44 is connected to the fluorine-chlorine stripping condensate tank 42. The fluorine-chlorine stripping condensate tank 42 is connected to the evaporation condensate tank through the fluorine-chlorine stripping condensate pump 43 installed on the pipeline. The cool water from the cooling tower 60 enters the fluorine-chlorine stripping condenser 44 and is returned to the cooling tower 60 by the circulating cooling water pump 59. In this embodiment, the fluorine-chlorine stripping tower 65 can also be heated by the air heater 66, and the gas of the air heater 66 comes from the compressed air of the air compressor station.

[0040] The exhaust gas treatment system is as follows: exhaust gas from the vacuum unit 45 and other equipment exhaust ports is collected through pipelines and then fed into the primary absorption tower 51. The top outlet of the primary absorption tower 51 is connected to the secondary absorption tower 54. The lower outlet of the primary absorption tower 51 is connected to the primary absorption tower cooler 53 via a primary absorption tower circulation pump 52 installed on a pipeline, and to the calcium fluoride filter press 61 via a calcium fluoride filter press pump 50 installed on a pipeline. The outlet of the calcium fluoride filter press 61 is connected to the calcium chloride liquid tank 49 via one outlet and to the primary absorption tower 51 via the other outlet. The calcium chloride liquid tank 49 is connected to the calcium chloride liquid pump installed on the pipeline. 48 is connected to the calcium chloride solution storage tank; the primary absorption tower cooler 53 is connected to the upper inlet of the primary absorption tower 51; the cooled water from the cooling tower 60 enters the primary absorption tower cooler 53 and is returned to the cooling tower 60 by the circulating cooling water pump 59; the top outlet of the secondary absorption tower 54 discharges the exhaust gas through the induced draft fan 56 installed on the pipeline; the lower outlet of the secondary absorption tower 54 is connected to the upper inlet of the secondary absorption tower 54 and the lower inlet of the primary absorption tower 51 through the secondary absorption tower circulating pump 55 installed on the pipeline; the calcium chloride solution preparation tank 46 is connected to the secondary absorption tower 54 through the calcium chloride solution pump 47 installed on the pipeline.

[0041] The sealing water system is as follows: after the cooling water from the cooling tower 60 enters the sealing water tank 57, it is returned to the cooling tower 60 by the circulating cooling water pump 59. All the sealing water pumped out flows into the sealing water tank 57, is cooled by the cooling circulating water through the coil in the sealing water tank, and then enters each pump that needs sealing water.

[0042] In this embodiment, the hydrogen sulfide generator 5, the first heavy metal remover 11, the second heavy metal remover 13, the fluorine and chlorine stripping heater 20, the first-effect evaporator 23, and the fluorine and chlorine stripping tower 65 are heated by external live steam. The non-condensable gases generated by the waste sulfuric acid tank 1, the sodium hydrogen sulfide solution preparation tank 3, the hydrogen sulfide scrubbing tower 7, the waste sulfuric acid storage tank 15, the vacuum unit 45, the sealed water tank 57, the calcium fluoride filter press 61, and the impurity removal plate and frame filter press 67 enter either the calcium hydroxide solution preparation tank 46 or the primary absorption tower 51. The following components are included: sodium hydrogen sulfide solution preparation tank 3, hydrogen sulfide generator 5, hydrogen sulfide tail gas absorption tank 8, first heavy metal remover 11, second heavy metal remover 13, waste sulfuric acid storage tank 15, first-effect separator 24, third-effect separator 34, vacuum unit 45, calcium chloride solution preparation tank 46, calcium chloride solution tank 49, first-stage absorption tower 51, second-stage absorption tower 54, sealed water tank 57, cooling water tower pool, second-effect separator 63, and fluoride-chlorine stripping tower 65, through which process water is introduced.

[0043] The working principle of this utility model is as follows:

[0044] 1. Flowchart of the reaction impurity removal system

[0045] 1) Hydrogen sulfide generation process:

[0046] Sodium hydrosulfide from the outside is first fed into sodium hydrosulfide solution preparation tank 3, where process water or hydrogen sulfide tail gas absorption liquid is used to prepare sodium hydrosulfide solution. Then, it is pumped by sodium hydrosulfide solution pump 4 to sodium hydrosulfide solution filter for filtration before entering hydrogen sulfide generator 5. At the same time, fluorine-free sulfuric acid solution from the outside is also pumped into hydrogen sulfide generator 5. In hydrogen sulfide generator 5, the materials are heated and stirred to ensure a full reaction. The generated hydrogen sulfide is led to heavy metal removal device through ejector. After the reaction in hydrogen sulfide generator 5 is completed, sodium sulfate solution is discharged by sodium sulfate solution discharge pump 6 for reuse or further treatment.

[0047] 2) Sulfuric acid reaction for impurity removal:

[0048] Waste sulfuric acid in waste sulfuric acid tank 1 or pool is first pumped to heavy metal removal device by waste sulfuric acid pump 2. In heavy metal removal device, waste sulfuric acid and hydrogen sulfide react fully under the action of stirring and jet circulation pump and ejector. The solution after reaction is pumped to impurity removal plate and frame filter press 67 by waste sulfuric acid filter press 14 for impurity removal filtration. The filter residue is collected and transported off-site. The clear liquid produced by filtration flows directly to impurity removal waste sulfuric acid storage tank 15 for buffering. Finally, it is pumped to evaporation concentration system by sulfuric acid evaporation feed pump 16 for the next step of concentration treatment.

[0049] 2. Evaporation and Concentration System Flowchart

[0050] 1) Material flow:

[0051] The sulfuric acid solution (hereinafter referred to as material) filtered from the reaction impurity removal system is first pumped into the preheater 35 by the sulfuric acid evaporation feed pump 16. It is preheated by the heat of the secondary steam from the triple-effect separator 34. After preheating, it enters the triple-effect evaporator group.

[0052] The material in the triple-effect evaporator group is heated and circulated in the triple-effect evaporator 32 by the triple-effect evaporation circulation pump 33. After being heated, the material undergoes vapor-liquid separation in the triple-effect separator 34. The material after preliminary concentration is pumped to the double-effect evaporator group by the double-effect feed pump 31.

[0053] The material in the double-effect evaporator group is heated and circulated in the double-effect evaporator 30 by the double-effect evaporation circulation pump 29. After being heated, the material undergoes vapor-liquid separation in the double-effect separator 63. The material after further concentration is pumped to the first-effect evaporator group by the first-effect feed pump 28.

[0054] The material in the first-effect evaporator group is heated and circulated in the first-effect evaporator 23 by the first-effect evaporation circulation pump 25. After being heated, the material undergoes vapor-liquid separation in the first-effect separator 24. Finally, the concentrated material is diverted to the high-temperature stripping system for further processing by the first-effect evaporation circulation pump 25.

[0055] The liquid level of each separator is automatically adjusted to control the feed and discharge, thereby achieving automatic and continuous feeding and discharging of materials, and ensuring that the evaporation system is in a high-efficiency and stable evaporation state.

[0056] 2) Steam heating process:

[0057] The raw steam from the outside first enters the material in the shell side of the first-effect evaporator 23 and the heating tube side. The heated material undergoes flash evaporation and vapor-liquid separation in the first-effect separator 24. The generated secondary steam is sprayed through the first saturator 64 and then enters the material in the shell side of the second-effect evaporator 30 and the heating tube side. The heated material undergoes flash evaporation and vapor-liquid separation in the second-effect separator 63. The generated secondary steam is sprayed through the second saturator 62 and then enters the material in the shell side of the third-effect evaporator 32 and the heating tube side. The heated material undergoes flash evaporation and vapor-liquid separation in the third-effect separator 34. Finally, most of the generated secondary steam enters the condenser tube side and is condensed, while a small portion enters the shell side of the preheater 35 to preheat the feed of the evaporation and concentration system.

[0058] 3) Condensate flow:

[0059] a. Steam condensate flow:

[0060] The steam condensate from the shell side of the first-effect evaporator flows into the steam condensate tank by pressure difference, and is finally pumped out or reused by the steam condensate pump.

[0061] b. Evaporation and condensate water process:

[0062] The evaporation condensate (recovered separately) in the shell side 23 of the second-effect evaporator flows to the evaporation condensate tank 22 of the first-effect evaporator by pressure difference, and is finally pumped out or reused by the evaporation condensate pump 21 of the first-effect evaporator.

[0063] The evaporative condensate from the shell side of the triple-effect evaporator 32 flows to the triple-effect evaporative condensate tank 36 by pressure difference. The evaporative condensate from the preheater 35 and the condenser also flows to the triple-effect evaporative condensate tank 36 by pressure difference. Finally, it is pumped out by the triple-effect evaporative condensate pump 37 for reuse or further treatment. A small portion of the triple-effect evaporative condensate is pumped to each saturator by the saturation pump 40 to spray superheated secondary steam.

[0064] 4) Non-condensable gas system process:

[0065] The vacuum system consists of a condenser, a triple-effect evaporator condensate tank 36, and a vacuum unit 45. Secondary steam generated in the triple-effect separator 34 enters the tube side of the condenser for condensation. The resulting evaporator condensate and non-condensable gases flow into the evaporator condensate tank. Then, the non-condensable gases (steam, air, or other non-condensable gases) are extracted from the top of the evaporator condensate tank by the vacuum unit 45. After gas-liquid separation in the water tank of the vacuum unit 45, the gases are discharged into the exhaust gas collection pipeline. Simultaneously, the vacuum pump maintains the required vacuum level for the entire evaporation crystallization system.

[0066] 3. High-temperature stripping system process

[0067] 1) Material flow:

[0068] The concentrated material from the evaporation and concentration system first enters the fluorine-chlorine stripping tower 65. Then, the fluorine-chlorine stripping heating pump 19 circulates and heats the material in the fluorine-chlorine stripping heater 20. After heating, the material undergoes vapor-liquid separation in the lower part of the fluorine-chlorine stripping tower 65. The concentrated material is then pumped to the upper part of the fluorine-chlorine stripping tower 65 by the fluorine-chlorine stripping circulation pump 18. The material is then stripped using the secondary steam separated by the evaporation and concentration in the lower part. Finally, the material is diverted to the concentrated sulfuric acid cooler 17 by the fluorine-chlorine stripping circulation pump 18, where it is cooled by circulating cooling water before being pumped out for storage.

[0069] The high-temperature stripping system can also be used to strip using high-temperature compressed air or air. It can be used when the output and stripping requirements are not high. There are multiple operating modes for fluorinated and chlorine stripping to meet the requirements of different working conditions.

[0070] The liquid level in the fluorine-chlorine stripping tower 65 is automatically adjusted to control the feed and discharge, thereby achieving automatic and continuous feeding and discharging of materials and ensuring that the evaporation system is in a high-efficiency and stable evaporation state.

[0071] 2) Steam heating process:

[0072] Raw steam from the outside enters the shell side of the fluorine-chlorine stripping heater 20 to heat the material in the tube side. The heated material undergoes flash evaporation in the lower part of the fluorine-chlorine stripping tower 65 for vapor-liquid separation. The generated secondary steam strips the fluorine and chlorine from the system material. After completion, it is sprayed through the third saturator 70 and then directly enters the tube side of the fluorine-chlorine stripping condenser 44 to be condensed.

[0073] 3) Steam condensate flow:

[0074] a. Steam condensate flow:

[0075] The steam condensate from the shell side of the fluorine-chlorine stripping heater 44 also flows to the steam condensate tank 22 by pressure difference, and is finally pumped out or reused by the steam condensate pump 21.

[0076] b. Evaporation and condensate water process:

[0077] The evaporative condensate (recovered separately) generated in the tube side of the fluorine-chlorine stripping condenser 44 flows to the fluorine-chlorine stripping condensate tank 42 by pressure difference, and is finally pumped out by the fluorine-chlorine stripping condensate pump 43 for reuse or reprocessing.

[0078] 4) Non-condensable gas system process:

[0079] The vacuum system consists of a fluorine-chlorine stripping condenser 44, a fluorine-chlorine stripping condensate tank 42, and a vacuum unit 45. The secondary steam generated in the fluorine-chlorine stripping tower 65 enters the tube side of the fluorine-chlorine stripping condenser 44 for condensation. The resulting evaporation condensate and non-condensable gases flow into the fluorine-chlorine stripping condensate tank 42. Then, the non-condensable gases (steam, air, or other non-condensable gases) are extracted from the top of the fluorine-chlorine stripping condensate tank 42 by the vacuum unit 45. After gas-liquid separation in the water tank of the vacuum unit 45, the gases are discharged into the tail gas collection pipeline. Simultaneously, the vacuum pump maintains the required vacuum level for the entire evaporation crystallization system.

[0080] 4. Exhaust gas treatment system process

[0081] 1) Exhaust gas process:

[0082] The exhaust gas from the vacuum unit 45 and other equipment outlets is collected through pipelines and then first flows into the primary absorption tower 51. In the primary absorption tower 51, the exhaust gas flows from bottom to top. The absorbent liquid is pumped by the primary absorption tower circulation pump 52 to the primary absorption cooler 53 for cooling, and then flows down from the top of the tower. Through countercurrent exchange with the exhaust gas, the exhaust gas in the tower is absorbed multiple times. Finally, a small amount of exhaust gas enters the secondary absorption tower 54 for further absorption.

[0083] The exhaust gas entering the secondary absorption tower 54 flows from bottom to top. The absorbent liquid is pumped to the top of the tower by the secondary absorption tower circulation pump 55 and flows downward. Through multiple cycles of countercurrent exchange with the exhaust gas, the exhaust gas in the tower is completely absorbed. Finally, the exhaust gas exiting the secondary absorption tower is discharged by the induced draft fan 56.

[0084] 2) Absorption liquid process:

[0085] The absorbent solution prepared from the calcium hydroxide solution preparation tank 46 is pumped to the secondary absorption tower 54 via the calcium hydroxide solution pump 47. After absorption, it is pumped to the primary absorption tower 51 via the secondary absorption circulation pump 55, and finally to the calcium fluoride filter press 61 via the calcium fluoride filter press pump 50 for filtration. The filtered residue is collected and transported off-site. The clear liquid produced by filtration flows directly to the calcium chloride solution tank 49 for buffering, and is finally pumped out via the calcium chloride solution pump 48 for further processing.

[0086] 5. Sealed Water System Flow

[0087] The sealing water system consists of a sealing water tank 57 and a sealing water pump 58. All the sealing water pumped out flows into the sealing water tank 57, where it is cooled by circulating cooling water through the coils before entering the pumps that require sealing water. After circulating for a period of time, the water in the sealing water tank is replaced in a timely manner.

Claims

1. A waste sulfuric acid evaporation and concentration and fluorine-chlorine stripping device, characterized in that: It includes a reaction impurity removal system, an evaporation and concentration system, a high-temperature stripping system, a tail gas treatment system, and a sealing water system; The aforementioned reaction purification system is as follows: sodium hydrosulfide from the outside enters the sodium hydrosulfide solution preparation tank (3). The lower part of the sodium hydrosulfide solution preparation tank (3) is connected to the upper inlet of the hydrogen sulfide generator (5) via a sodium hydrosulfide solution pump (4) installed on a pipeline. Fluorine-free sulfuric acid solution from the outside enters the hydrogen sulfide generator (5). The lower outlet of the hydrogen sulfide generator (5) is connected to the sodium sulfate solution storage tank via a sodium sulfate solution discharge pump (6) installed on a pipeline. The upper outlet of the hydrogen sulfide generator (5) is connected to the inlet of the hydrogen sulfide scrubbing tower (7) via one route and to the first injector (69) and the second injector (68) via another route. The bottom of the hydrogen sulfide scrubbing tower (7) is connected to the hydrogen sulfide tail gas absorption tank (8). The hydrogen sulfide tail gas absorption tank (8) is connected to the hydrogen sulfide scrubbing tower (7) via a hydrogen sulfide absorption liquid pump (9) installed on the pipeline via one route and to the sodium sulfide solution preparation tank (3) via another route. The outlet of a first ejector (69) is connected to a first heavy metal remover (11), and the outlet of a second ejector (68) is connected to a second heavy metal remover (13). The first heavy metal remover (11) is connected to the first ejector (69) via a jet circulation pump (12) installed on a pipeline, and the second heavy metal remover (13) is connected to the second ejector (68) via a jet circulation pump (12) installed on a pipeline. The waste sulfuric acid tank (1) is connected to the second ejector (68) via a jet circulation pump (12) installed on a pipeline. The waste sulfuric acid pump (2) on the pipeline is connected to the first heavy metal remover (11) and the second heavy metal remover (13). The second heavy metal remover (13) is connected to the impurity removal plate and frame filter press (67) through the waste sulfuric acid filter press (14) installed on the pipeline. The outlet of the impurity removal plate and frame filter press (67) is connected to the impurity removal waste sulfuric acid storage tank (15). The impurity removal waste sulfuric acid storage tank (15) is connected to the evaporation and concentration system through the sulfuric acid evaporation feed pump (16) installed on the pipeline. The evaporation and concentration system is as follows: the sulfuric acid solution pumped in by the sulfuric acid evaporation feed pump (16) enters the preheater (35). The outlet of the preheater (35) is connected to the inlet of the triple-effect evaporator (32) through the triple-effect evaporation circulation pump (33) installed on the pipeline. The outlet of the triple-effect evaporator (32) is connected to the triple-effect separator (34). The top outlet of the triple-effect separator (34) is connected to the preheater (35), the first condenser (38), and the second condenser (39). The cool water from the cooling tower (60) enters the second condenser (39) and the first condenser (38) in sequence and then returns to the cooling tower (60) by the circulating cooling water pump (59). The cool water from the cooling tower (60) enters the third condenser (41) and then returns to the cooling tower (60) by the circulating cooling water pump (59). The lower outlets of the first condenser (38) and the second condenser (39) are connected to the top inlet of the third condenser (41). The concentrated solution in the triple-effect separator (34) is... The concentrated material enters the second-effect evaporator (30) through the second-effect feed pump (31). The outlet of the second-effect evaporator (30) is connected to the second-effect separator (63). The top outlet of the second-effect separator (63) is connected to the third-effect evaporator (32) through the second saturator (62), and the bottom outlet is connected to the second-effect evaporator (30) through the second-effect evaporation circulation pump (29) installed on the pipeline. The concentrated material in the second-effect separator (63) enters the first-effect evaporator (23) through the first-effect feed pump (28) installed on the pipeline. The outlet of the first-effect evaporator (23) is connected to the inlet of the first-effect separator (24). The top outlet of the first-effect separator (24) is connected to the inlet of the second-effect evaporator (30) through the first saturator (64), and the bottom outlet is connected to the first-effect evaporation circulation pump (25) installed on the pipeline. The concentrated material in the first-effect separator (24) enters the high-temperature stripping system. The condensate from the double-effect evaporator (30) enters the first-effect evaporation condensate tank (27) and is then pumped into the evaporation condensate storage tank by the first-effect evaporation condensate pump (26). The steam condensate from the first-effect evaporator (23) enters the steam condensate tank (22) and is then pumped into the boiler by the steam condensate pump (21). The condensate and non-condensable gas generated by the triple-effect evaporator (32), preheater (35), first condenser (38), second condenser (39), and third condenser (41) enter the triple-effect evaporation condensate tank (36). The non-condensable gas at the top of the triple-effect evaporation condensate tank (36) enters the vacuum unit (45). The bottom of the triple-effect evaporation condensate tank (36) is connected to the evaporation condensate tank by the triple-effect evaporation condensate pump (37) installed on the pipeline, and the other path enters the first saturator (64), the second saturator (62), and the third saturator (70) through the saturation pump (40). The high-temperature stripping system is as follows: the concentrated material in the first-effect separator (24) enters the fluorine-chlorine stripping heater (20) through the fluorine-chlorine stripping heating pump (19). The lower outlet of the fluorine-chlorine stripping heater (20) is connected to the steam condensate tank (22), and the top outlet is connected to the fluorine-chlorine stripping tower (65). The lower outlet of the fluorine-chlorine stripping tower (65) is connected to the upper inlet of the fluorine-chlorine stripping tower (65) through a fluorine-chlorine stripping circulation pump (18) installed on the pipeline, and the other path is connected to the concentrated sulfuric acid cooler (17). The cool water from the cooling tower (60) enters the concentrated sulfuric acid cooler (17) and is then circulated for cooling. The water pump (59) returns to the cooling tower (60), and the concentrated sulfuric acid in the concentrated sulfuric acid cooler (17) is connected to the sulfuric acid storage tank; the top outlet of the fluorine-chlorine stripping tower (65) is connected to the fluorine-chlorine stripping condenser (44) through the third saturator (70), and the bottom outlet of the fluorine-chlorine stripping condenser (44) is connected to the fluorine-chlorine stripping condensate tank (42). The fluorine-chlorine stripping condensate tank (42) is connected to the evaporation condensate tank through the fluorine-chlorine stripping condensate pump (43) installed on the pipeline. The cool water from the cooling tower (60) enters the fluorine-chlorine stripping condenser (44) and then returns to the cooling tower (60) by the circulating cooling water pump (59); The exhaust gas treatment system is as follows: exhaust gas from the vacuum unit (45) and other equipment exhaust ports is collected through pipelines and then fed into the primary absorption tower (51). The top outlet of the primary absorption tower (51) is connected to the secondary absorption tower (54). The lower outlet of the primary absorption tower (51) is connected to the primary absorption tower cooler (53) through the primary absorption tower circulation pump (52) installed on the pipeline, and to the calcium fluoride filter press (61) through the calcium fluoride filter press pump (50) installed on the pipeline. The outlet of the calcium fluoride filter press (61) is connected to the calcium chloride liquid tank (49) through one channel and to the primary absorption tower (51) through the other channel. The calcium chloride liquid tank (49) is connected to the calcium chloride liquid pump (48) installed on the pipeline. The first-stage absorption tower cooler (53) is connected to the upper inlet of the first-stage absorption tower (51). The cool water from the cooling tower (60) enters the first-stage absorption tower cooler (53) and is then returned to the cooling tower (60) by the circulating cooling water pump (59). The exhaust gas from the top outlet of the second-stage absorption tower (54) is discharged by the induced draft fan (56) installed on the pipeline. The lower outlet of the second-stage absorption tower (54) is connected to the upper inlet of the second-stage absorption tower (54) by one path and to the lower inlet of the first-stage absorption tower (51) by the second-stage absorption tower circulating pump (55) installed on the pipeline. The calcium chloride solution preparation tank (46) is connected to the second-stage absorption tower (54) by the calcium chloride solution pump (47) installed on the pipeline. The sealing water system is as follows: the cool water from the cooling tower (60) enters the sealing water tank (57) and is then returned to the cooling tower (60) by the circulating cooling water pump (59). All the sealing water pumped out flows into the sealing water tank (57), is cooled by the cooling circulating water through the coil in the sealing water tank, and then enters each pump that needs sealing water.

2. The waste sulfuric acid evaporation and concentration and fluorine-chlorine stripping device according to claim 1, characterized in that: The first heavy metal remover (11) and the second heavy metal remover (13) are supplied with ozone by the ozone generator (10).

3. The waste sulfuric acid evaporation and concentration and fluorine-chlorine stripping device according to claim 1, characterized in that: The fluorine-chlorine stripping tower (65) is heated by an air heater (66), and the gas in the air heater (66) comes from compressed air from an air compressor station.

4. The waste sulfuric acid evaporation and concentration and fluorine-chlorine stripping device according to claim 1, characterized in that: The hydrogen sulfide generator (5), the first heavy metal remover (11), the second heavy metal remover (13), the fluorine and chlorine stripping heater (20), the first-effect evaporator (23), and the fluorine and chlorine stripping tower (65) are heated by external live steam.

5. The waste sulfuric acid evaporation and concentration and fluorine-chlorine stripping device according to claim 1, characterized in that: The non-condensable gas generated by the waste sulfuric acid tank (1), sodium hydrogen sulfide solution preparation tank (3), hydrogen sulfide scrubbing tower (7), waste sulfuric acid storage tank (15), vacuum unit (45), sealed water tank (57), calcium fluoride filter press (61), and impurity removal plate and frame filter press (67) enters the calcium hydroxide solution preparation tank (46) in one direction and the primary absorption tower (51) in the other direction.

6. The waste sulfuric acid evaporation and concentration and fluorine-chlorine stripping device according to claim 1, characterized in that: Process water is introduced into the sodium hydrogen sulfide solution preparation tank (3), hydrogen sulfide generator (5), hydrogen sulfide tail gas absorption tank (8), first heavy metal remover (11), second heavy metal remover (13), waste sulfuric acid storage tank (15), first-effect separator (24), third-effect separator (34), vacuum unit (45), calcium chloride solution preparation tank (46), calcium chloride solution tank (49), first-stage absorption tower (51), second-stage absorption tower (54), sealed water tank (57), cooling water tower pool, second-effect separator (63), and fluoride-chlorine stripping tower (65).

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