A waste sulfuric acid resource recycling rotary evaporation treatment device

Abstract

A kind of waste sulfuric acid resourceization rotary evaporation processing device, including rotary evaporator and the hollow rotating shaft being arranged in the rotary evaporator, the hollow rotating shaft is rotated by motor being arranged at one end thereof drive, heat source enters along one end of hollow rotating shaft, is discharged from the other end, multiple annular fins are vertically arranged on hollow rotating shaft, the annular fin includes two cymbal flakes, cymbal flake inner circle is welded to hollow rotating shaft, cymbal flake outer circle top is mutually welded, and forms closed area, multiple baffle plates for changing the flow direction of heat source are arranged in the cavity of the annular fin.The waste sulfuric acid rotary evaporation technology and device of the present application, hollow annular fin is used to heat in the form of thin film to carry out heat exchange, wing piece alternately contacts with dilute sulfuric acid waste liquid and negative pressure steam, when hollow wing piece is immersed in waste sulfuric acid, heat exchange waste liquid and continue stirring, when hollow wing piece is exposed to steam, surface area liquid is evaporated, effectively improve system heat exchange efficiency.

Description

Technical Field

[0001] This invention belongs to the field of industrial wastewater regeneration and recycling in environmental protection, and specifically relates to a rotary evaporation treatment device for the resource recovery of waste sulfuric acid. Background Technology

[0002] Sulfuric acid is a commonly used raw material in industrial manufacturing, widely used in chemical, metallurgical, and petroleum industries. With the continuous growth of sulfuric acid consumption, the amount of industrial waste sulfuric acid is also increasing year by year. Industries that mainly generate waste sulfuric acid include the sulfuric acid process for titanium dioxide, non-ferrous metal smelting, petroleum processing, steel pickling, dyeing, and pesticide industries. Direct discharge of untreated waste sulfuric acid into environmental water bodies poses significant environmental risks. To address the waste sulfuric acid pollution problem, researchers have developed waste sulfuric acid treatment technologies such as neutralization, high-temperature pyrolysis, extraction, polymerization, and concentration crystallization.

[0003] Neutralization consumes a large amount of alkali, and alkali treatment introduces high concentrations of inorganic salts. In today's environment of increasingly strict control over total dissolved solids in wastewater, its popularity is gradually declining.

[0004] The high-temperature pyrolysis method mainly consists of the following two steps:

[0005]

[0006] 2SO3(g)⇌2SO2(g)+O2(g) △H=+196k·mol -1

[0007] High-temperature pyrolysis methods have high operating costs because the reaction requires a large amount of heat.

[0008] Existing technologies for recovering sulfuric acid from waste acid through extraction utilize amine extractants to selectively extract sulfuric acid, which is then recycled and reused, achieving good economic benefits. However, this method introduces a large amount of amine organic matter, which is difficult to process after treatment, often requiring additional costs for reprocessing.

[0009] Evaporation crystallization, especially negative pressure evaporation crystallization technology, has become a mainstream technology due to its lower energy consumption compared to high-temperature pyrolysis, as it involves no added foreign substances and allows for efficient reuse when waste sulfuric acid contains few impurities. Existing evaporation crystallization technologies for wastewater sulfuric acid mainly include steam evaporation purification, crucible heating, and concentration crystallization. The core of evaporation crystallization technology is the evaporator. Evaporator equipment mainly includes circulating evaporators, single-pass evaporators, and scraped-film evaporators. Among them, the scraped-film evaporator is a new and highly efficient evaporation device, suitable for processing heat-sensitive materials, viscous materials, and materials prone to scaling and foaming. The scraper agitation prevents clogging. For example, in publicly available scraped-film evaporators, the scraper body effectively adheres to the inner wall of the evaporator body, and a rotating frame scrapes away the raw material adhering to the inner wall of the evaporator body, improving the cleanliness of the device. However, these improvements do not directly contribute to improving heat exchange efficiency. A chemical limited company's epoxy resin plant imported two Type I scraped-film evaporators, one for evaporating and recovering chloropropane and solvent from the epoxy resin mother liquor. A chemical fiber company uses domestically produced 15m... 2 The scraped-film evaporator refines caprolactam solution, achieving a concentration of approximately 99.5% after condensation. Weihai Runlan Water Treatment Equipment Co., Ltd. utilizes steam as an alternative energy source for heating, distilling and drying wastewater at a low temperature of 35℃. A scraper continuously stirs the solution, automatically discharging the dried powdery solids.

[0010] In general, the aforementioned technologies have been developed to address waste sulfuric acid by improving thermal efficiency, recycling valuable sulfuric acid, reducing blockages, and altering heat sources. However, these existing technologies and equipment suffer from the following problems:

[0011] 1. Low thermal efficiency, requiring evaporation temperatures as high as 150~300℃, some low-temperature distillation, high negative pressure, consuming a large amount of heat energy and power;

[0012] 2. The scraper material is not corrosion resistant and has a short service life, which is particularly prominent in the process treatment of sulfuric acid wastewater. The discharge of dried solid products is prone to blockage, resulting in a high machine failure rate.

[0013] 3. The gap between the scraper and the inner wall of the evaporator is 1~2mm, which requires high processing precision and is costly.

[0014] To improve heat exchange efficiency, technological development often focuses on heat exchange materials and areas, such as replacing steel tubes with copper tubes and plate heat exchangers with tube heat exchangers. However, the potential for further improvement in these technologies is extremely limited. Some researchers also focus on heat exchange structures. For example, rotary evaporators in chemical experiments utilize negative pressure operation to reduce temperature and save energy, and have a large heat exchange area. In particular, the alternating heat exchange between the liquid and gas phases on the heat exchange surface provides a new approach to improving heat exchange efficiency. However, the rotation of the reaction flask in rotary evaporation requires very high precision in negative pressure operation, limiting its large-scale development in practical engineering. Summary of the Invention

[0015] To overcome the above shortcomings, this invention provides a rotary evaporation treatment device for the resource recovery of waste sulfuric acid. Based on the characteristics of sulfuric acid wastewater and combined with the compositional characteristics of pollutants, sulfuric acid, and water, it enables efficient removal of organic matter, recovery of sulfuric acid, and reuse of water resources, thereby achieving a balance between environmental and economic benefits.

[0016] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0017] A rotary evaporation treatment device for the resource recovery of waste sulfuric acid includes a rotary evaporator and a hollow rotary shaft disposed within the rotary evaporator. The hollow rotary shaft is driven to rotate by a motor disposed at one end. A heat source enters along one end of the hollow rotary shaft and exits from the other end. Multiple annular blades are vertically disposed on the hollow rotary shaft. Each annular blade includes two cymbal-shaped thin plates. The inner ring of the cymbal-shaped thin plates is welded to the hollow rotary shaft, and the top of the outer ring of the cymbal-shaped thin plates is welded together to form a closed area. Multiple baffles for changing the flow direction of the heat source are disposed within the cavity of the annular blades.

[0018] Further optimization involves a circular baffle plate with its inner ring welded to a hollow rotating shaft. The hollow rotating shaft has 4-6 rings of small inlet and outlet holes arranged from left to right, with 2-3 rings being inlet holes and 2-3 rings being outlet holes.

[0019] Further optimization involves providing a material inlet at one end of the rotary evaporator and a material outlet and a steam outlet at the other end. The material inlet, the material outlet, and the steam outlet are flexibly connected to a water inlet pipe, a water outlet pipe, and a steam outlet pipe, respectively.

[0020] Further optimization involves providing one or more structures on the surface of the annular wing, such as cross-shaped, hemispherical, tetrahedral protrusions, or grooves.

[0021] Further optimizations include a vacuum of 0.06~0.1MPa on the evaporation surface of the inner wall of the rotary evaporator, a distance of 1~3cm between the annular fins and the inner wall of the evaporator during operation, and an evaporation temperature of 47~64℃.

[0022] Further optimization involves using one of the following materials for the annular fins: tantalum, platinum, or titanium. A graphite slider is used to seal the hollow rotating shaft from the inner wall of the rotary evaporator.

[0023] Further optimizations include a condenser and a cooling tower. The condenser is connected to the rotary evaporator via a steam pipe, and the cooling tower is connected to the condenser via a circulating water pipe. The water vapor evaporated by the evaporator is condensed by the condenser and enters the gas-liquid separator, which is connected to the vacuum pump. The refrigerant required by the condenser comes from the cooling tower. After being heated in the condenser, the refrigerant returns to the cooling tower for cooling and is then recycled.

[0024] The beneficial effects of this invention are as follows:

[0025] (1) Secondary steam is pumped from the evaporator to the condenser, so the entire evaporator can maintain a high vacuum. The increase in vacuum effectively reduces the boiling point of the processed material. The hollow blades are required to maintain a distance of 1~3cm from the inner wall of the equipment cylinder during operation, which reduces the difficulty of construction and installation. The working temperature required for this machine is 47℃~64℃.

[0026] (2) The steam overflowing from the evaporator is condensed and used as a secondary heating source. The side discharge method replaces the bottom discharge method, which increases the outlet area of ​​the scraped film evaporator and increases the working efficiency of the rotary evaporator. Hot water is introduced through the middle shaft. The equipment reduces the thickness of the entire steam film by 20% by rotating, which improves the heat transfer coefficient and forms an internal vacuum structure.

[0027] (3) Use titanium alloy to make hollow annular blades for rotary evaporators to reduce corrosion and reduce evaporator maintenance and operating costs. Add intelligent sensing equipment to the central rotating shaft of the rotary evaporator to automatically monitor the working effect of the scraped film evaporator. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of the present invention;

[0029] Figure 2 This is a schematic diagram of the structure of a rotary evaporator;

[0030] Figure 3 for Figure 2 A schematic diagram of direction A;

[0031] Figure 4 for Figure 2 A schematic diagram of direction B;

[0032] Figure 5 This is the front view of the annular winglet;

[0033] Figure 6 This is a cross-sectional view of the annular winglet;

[0034] Attached diagram descriptions: 1. Material inlet, 2. Hollow rotating shaft, 3. Annular vane, 4. Rotary evaporator, 5. Material outlet, 6. Distilled water pump, 7. Distilled water tank, 8. Vacuum pump, 9. Gas-liquid separator, 10. Cooling tower, 11. Exhaust valve, 12. Condenser, 13. Steam outlet pipe, 14. High-speed motor, 15. Vibrating motor. Detailed Implementation

[0035] The technical solutions in the embodiments of the present invention will now be clearly and completely described with reference to the accompanying drawings.

[0036] A rotary evaporation treatment device for the resource recovery of waste sulfuric acid includes a rotary evaporator 4, a hollow rotating shaft 2, a condenser 12, and a cooling tower 10. The hollow rotating shaft 2 is installed inside the rotary evaporator 4. The condenser 12 is connected to the rotary evaporator 4 through a steam pipe. The cooling tower 10 is connected to the condenser 12 through a circulating water pipe. Water vapor is condensed by the condenser 12 and enters a gas-liquid separator 9. The refrigerant for the condenser 12 comes from the cooling tower 10. After being heated in the condenser 12, the refrigerant returns to the cooling tower 10, is cooled by cold air, and is then recycled. The hollow rotating shaft 2 is driven to rotate by a high-speed motor 14 located at one end. A heat source enters from one end of the hollow rotating shaft 2 and exits from the other end. Multiple annular blades 3 are vertically arranged on the hollow rotating shaft 2. Each annular blade 3 includes two cymbal-shaped thin plates. The inner rings of the cymbal-shaped thin plates are welded to the hollow rotating shaft, and the tops of the outer rings of the cymbal-shaped thin plates are welded together to form a closed area. A baffle plate, circular in shape, is provided within the cavity of the annular blade 3 to change the direction of heat source flow. The inner ring of the baffle plate is welded to the hollow rotating shaft. The 2 has 4-6 rings of small water inlet and outlet holes from left to right, of which 2-3 rings are water inlet holes and 2-3 rings are water outlet holes. The cavity of the annular fin 3 is provided with multiple baffles for changing the flow direction of the heat source. The surface of the annular fin 3 is provided with one or more structures such as cross-shaped, hemispherical, tetrahedral protrusions, and grooves. This structure facilitates the increase of heat exchange area and fluid turbulence. The annular fin 3 is made of one of tantalum, platinum, or titanium. The hollow rotating shaft 2 and the inner wall of the rotary evaporator 4 are sealed with a graphite slider.

[0037] The rotary evaporator has a material inlet at one end and a material outlet and a steam outlet at the other end. The material inlet, the material outlet, and the steam outlet are flexibly connected to a water inlet pipe, a water outlet pipe, and a steam outlet pipe, respectively. The vacuum of the evaporation surface on the inner wall of the evaporator is 0.06~0.1MPa. When the annular fins are in operation, the distance between them and the inner wall of the evaporator is 1~3cm, and the evaporation temperature is 47~64℃.

[0038] Working process: The high-speed motor 14 drives the hollow rotating shaft to rotate at a speed of 240~300 rpm. Heating steam (or hot water) is introduced into the hollow rotating shaft. The hot steam (or hot water) enters the annular vane 3 through the small hole in the central shaft. The rotary evaporator 4 is connected to the oscillating motor 15. Under the action of the oscillating motor 15, the rotation angle range is 90~120°, and it rotates alternately in the clockwise-counterclockwise-clockwise-counterclockwise direction. The reciprocating rotation frequency is 30-60Hz. The steam outlet at the top of the rotary evaporator 4 is flexibly connected to the condenser 12. The hollow rotating shaft 2 and the inner wall of the rotary evaporator 4 are sealed with graphite sliders. At the same time, hot steam (hot water) is introduced into the annular vane 3 through the hollow rotating shaft. Shaft 2 is inserted, and the radial distribution is on the annular vane 3. Heat exchange occurs between the waste sulfuric acid and the casing of the rotary evaporator 4 through the thin film structure of the annular vane 3. Under the triple action of gravity, centrifugal force, and the annular vane 3, a swirling vapor film forms on the outer surface of the annular vane 3. As the annular vane 3 rotates, it continuously transfers heat, evaporates, and concentrates the material during the alternating contact between the liquid and gas phases, and continuously stirs the material. The liquid is discharged from the material outlet 5, and the secondary steam escapes from the steam pipe at the top of the rotary evaporator 4 into the condenser 12. Through multiple heat exchanges, the residual heat from the swirling vapor in the evaporated gas is used to heat the waste sulfuric acid feed water. The rotary evaporator 4 can evaporate and concentrate the solution to obtain a high-concentration sulfuric acid waste liquid that is directly discharged from the machine. The negative pressure steam discharged from the rotary evaporator 4 is connected to the condenser 12 through the steam pipe 13. The water vapor is condensed by the condenser 12 and enters the gas-liquid separator 9. The refrigerant in the condenser 12 comes from the cooling tower 10. After being heated in the condenser 12, the refrigerant returns to the cooling tower 10, is cooled by cold air, and is then recycled. The liquid separated by the gas-liquid separator 9 enters the distilled water tank 7, the gas separated by the gas separator enters the vacuum pump 8, the gas discharged by the vacuum pump 8 enters the atmospheric environment, the condensed water enters the distilled water tank 7, and the distilled water stored in the distilled water tank 7 is periodically reused in production.

[0039] The foregoing has shown and described the main features, usage methods, basic principles, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention based on actual circumstances without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A rotary evaporation treatment device for the resource recovery of waste sulfuric acid, characterized in that, The device includes a rotary evaporator (4) and a hollow rotary shaft (2) disposed within the rotary evaporator (4). The hollow rotary shaft (2) is driven to rotate by a motor disposed at one end. The heat source enters along one end of the hollow rotary shaft (2) and exits from the other end. Multiple annular blades (3) are vertically disposed on the hollow rotary shaft (2). Each annular blade (3) includes two cymbal-shaped thin plates. The inner ring of the cymbal-shaped thin plates is welded to the hollow rotary shaft (2), and the top of the outer ring of the cymbal-shaped thin plates is welded to each other to form a closed area. Multiple baffles for changing the flow direction of the heat source are disposed in the cavity of the annular blades (3). The baffles are circular, and the inner ring of the baffles is welded to the hollow rotary shaft (2). The hollow rotary shaft (2) is provided with 4-6 rings of water inlet and outlet holes from left to right, of which 2-3 rings are water inlet holes and 2-3 rings are water outlet holes.

2. The waste sulfuric acid resource recovery rotary evaporation treatment device as described in claim 1, characterized in that, The rotary evaporator (4) has a material inlet (1) at one end and a material outlet (5) and a steam outlet at the other end. The material inlet (1), the material outlet (5) and the steam outlet are flexibly connected to the water inlet pipe, the water outlet pipe and the steam outlet pipe (13), respectively.

3. The waste sulfuric acid resource recovery rotary evaporation treatment device as described in claim 2, characterized in that, The surface of the annular wing (3) is provided with one or more structures such as cross-shaped, hemispherical, tetrahedral protrusions, and grooves.

4. The waste sulfuric acid resource recovery rotary evaporation treatment device as described in claim 1, characterized in that, The vacuum of the evaporation surface of the inner wall of the rotary evaporator (4) is 0.06~0.1MPa. When the annular fins (3) are in operation, the distance between them and the inner wall of the rotary evaporator is 1~3cm, and the evaporation temperature is 47~64℃.

5. The waste sulfuric acid resource recovery rotary evaporation treatment device as described in claim 1, characterized in that, The annular wing (3) is made of one of tantalum, platinum or titanium, and the hollow rotating shaft (2) is sealed with a graphite slider between it and the inner wall of the rotary evaporator (4).

6. The waste sulfuric acid resource recovery rotary evaporation treatment device as described in claim 1, characterized in that, It also includes a condenser (12) and a cooling tower (10). The condenser (12) is connected to the rotary evaporator (4) through a steam pipe (13). The cooling tower (10) is connected to the condenser (12) through a circulating water pipe. The water vapor evaporated by the rotary evaporator (4) is condensed by the condenser (12) and enters the gas-liquid separator (9) which is connected to the vacuum pump. The refrigerant required by the condenser (12) comes from the cooling tower (10). After the refrigerant is heated in the condenser (12), it returns to the cooling tower (10) for cooling and is then recycled.

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