A purification device and purification method for sulfamic acid

Abstract

The present application relates to the technical field of chemical product purification, and particularly relates to a purification device and purification method for sulfamic acid, which comprises at least two cooling crystallization units arranged in series, each cooling crystallization unit comprises a crystallization container, a heat exchange assembly, a disturbance assembly and a temperature control unit, through the synergistic effect of the multi-stage cooling crystallization units and the independent temperature control units, the gradient fine temperature control of the sulfamic acid solution is realized, and the product purity is improved. A plurality of groups of heat exchange pipes arranged in parallel significantly increase the effective heat transfer area, and the solution turbulence and heat transfer efficiency are strengthened under the synergistic stirring of the disturbance assembly, and the energy consumption is reduced. At the same time, the disturbance effect effectively inhibits the adhesion and scaling of the crystals on the heat exchange surface, and the continuous production cycle is significantly prolonged in combination with the stable operation of the temperature control unit. By using the above structure, the high-efficiency, energy-saving and continuous industrial production target is realized while ensuring high purity.

Description

Technical Field

[0001] This invention relates to the field of chemical product purification technology, and in particular to a purification apparatus and method for aminosulfonic acid. Background Technology

[0002] Sulfamic acid, as an important fine chemical raw material, is widely used in industries such as electronic cleaning, metal surface treatment, electroplating, textile printing and dyeing, water treatment, and pharmaceuticals. Currently, the main industrial method for refining sulfamic acid is the cooling crystallization method, which involves cooling the solution to precipitate the sulfamic acid, followed by solid-liquid separation and drying to obtain a high-purity product.

[0003] However, traditional cooling crystallization processes and equipment have the following prominent problems: First, traditional cooling often adopts a single low-temperature rapid cooling mode, resulting in an unbalanced rate of temperature drop in the aminosulfonic acid solution (local temperature drop exceeding 50℃ / h), leading to uneven crystal particle size (particle size difference exceeding 30μm), easy encapsulation and residue of impurities, and difficulty in consistently achieving a purity of over 99.8%; Second, the heat exchange structure is mostly a tank wall jacket or a single heat exchange plate, resulting in insufficient contact between the material and the cooling surface, low heat transfer efficiency, a long cooling cycle of 8-10 hours, and high energy consumption per unit capacity; Third, during the cooling process, crystals easily adhere to the heat exchange surface to form a scale layer, requiring frequent shutdowns for cleaning, affecting production continuity, and the lack of cold energy recovery leads to energy waste.

[0004] In summary, existing purification equipment for the refining of aminosulfonic acid suffers from drawbacks such as single temperature control during the cooling process, low heat exchange efficiency, and severe scaling problems, making it difficult to achieve efficient, energy-saving, and continuous industrial production while ensuring high product purity. Summary of the Invention

[0005] The purpose of this invention is to provide a purification apparatus and method for aminosulfonic acid, which solves the problems of existing purification apparatus for aminosulfonic acid refining, such as single temperature control during the cooling process, low heat exchange efficiency, and serious scaling problems, making it difficult to achieve efficient, energy-saving, and continuous industrial production while ensuring high product purity.

[0006] To achieve the above objectives, the present invention provides a purification apparatus for aminosulfonic acid, the purification apparatus for aminosulfonic acid comprising at least two stages of cooling crystallization units arranged in series, wherein each two adjacent stages of the cooling crystallization units are connected by a material conveying pipeline, the inlet of the first stage of the cooling crystallization unit is used to receive the aminosulfonic acid solution to be processed, and the outlet of the last stage of the cooling crystallization unit is used to discharge the crystallized aminosulfonic acid slurry.

[0007] Each stage of the cooling crystallization unit includes a crystallization container, a heat exchange component, a disturbance component, and a temperature control unit. The heat exchange component is disposed inside the crystallization container. The heat exchange component consists of multiple parallel heat exchange tubes for introducing a cooling medium. The disturbance component is also disposed on the crystallization container for stirring the aminosulfonic acid solution during the crystallization process. The temperature control unit is also disposed on the crystallization container for controlling the temperature and flow rate of the cooling medium introduced into the heat exchange tubes of the cooling crystallization unit at that stage.

[0008] The cooling crystallization unit is preferably three-stage. Through the three-stage series cooling crystallization unit and its corresponding temperature control unit, the gradient cooling of the aminosulfonic acid solution can be achieved. The gradient cooling includes a first cooling stage, a second cooling stage and a third cooling stage.

[0009] Specifically, the first cooling stage involves cooling the aminosulfonic acid solution from 80-85°C to 55-60°C, with the cooling rate controlled at 15-20°C / h.

[0010] The second cooling stage specifically involves cooling the aminosulfonic acid solution from 55-60℃ to 30-35℃, with the cooling rate controlled at 10-12℃ / h.

[0011] The third cooling stage specifically involves cooling the aminosulfonic acid solution from 30-35℃ to 10-15℃, with the cooling rate controlled at 5-8℃ / h.

[0012] In each of the cooling crystallization units, the heat exchange tube is a reinforced heat transfer tube with a spiral groove on the inner wall.

[0013] In each of the cooling crystallization units, the disturbance component is a rotatable stirring blade, which is located around the corresponding heat exchange tube. The rotation axis of the stirring blade is parallel or perpendicular to the extension direction of the heat exchange tube.

[0014] Each of the cooling crystallization units is further provided with an ultrasonic generator, which is located outside the corresponding crystallization container and is used to generate ultrasonic waves into the crystallization container.

[0015] The purification apparatus for aminosulfonic acid further includes a precooling heat exchanger, which is used to precool the aminosulfonic acid solution before it enters the cooling crystallization unit of the first stage using a cooling medium whose temperature has increased from that of the cooling crystallization unit outside the first stage.

[0016] The precooling heat exchanger is either a plate heat exchanger or a shell-and-tube heat exchanger.

[0017] Each of the cooling crystallization units consists of a temperature sensor, a flow regulating valve, and a controller installed on the cooling medium pipeline.

[0018] The present invention also provides a method for purifying aminosulfonic acid, applied to the aminosulfonic acid purification apparatus as described above, comprising the following steps:

[0019] Provide a crude aminosulfonic acid solution with a concentration of 40-50 wt% and a temperature of 80-85℃;

[0020] After the purification device for aminosulfonic acid enters continuous steady-state operation, the crude aminosulfonic acid solution is introduced into the precooling heat exchanger to exchange heat with the cooling medium from the cooling crystallization unit outside the first stage, whose temperature has been raised to 25-30°C, so as to precool the crude aminosulfonic acid solution to 65-70°C.

[0021] The pre-cooled aminosulfonic acid solution is sequentially passed into the three-stage series cooling crystallization unit, and cooling crystallization is carried out in each stage according to the set gradient cooling process.

[0022] The aminosulfonic acid slurry discharged from the final stage of the cooling crystallization unit is subjected to solid-liquid separation, washing, and drying to obtain aminosulfonic acid crystals, thus completing the purification of aminosulfonic acid.

[0023] This invention discloses a purification apparatus and method for aminosulfonic acid, comprising at least two stages of cooling crystallization units arranged in series. Each stage of the cooling crystallization unit includes a crystallization container, a heat exchange component, a disturbance component, and a temperature control unit. Through the synergistic effect of the multi-stage series-connected cooling crystallization units and their independent temperature control units, gradient and precise temperature control of the aminosulfonic acid solution is achieved, avoiding the problems of uneven crystallization and impurity encapsulation caused by a single rapid cooling mode, thereby improving product purity. Multiple sets of parallel heat exchange tubes significantly increase the effective heat transfer area. The synergistic stirring of the disturbance component enhances solution turbulence and heat transfer efficiency, significantly shortening the cooling cycle and reducing energy consumption. Simultaneously, the disturbance effectively inhibits crystal adhesion and scaling on the heat exchange surface. Combined with the stable operation of the temperature control unit, this significantly extends the continuous production cycle. Using the above structure, high purity is ensured while achieving the goals of efficient, energy-saving, and continuous industrial production. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the structure of the purification apparatus for aminosulfonic acid provided by the present invention.

[0026] Figure 2 This is a flowchart of the purification method for aminosulfonic acid provided by the present invention.

[0027] 101-Crystallization container, 102-Disturbance component, 103-Heat exchange tube, 104-Ultrasonic generator, 105-Precooling heat exchanger, 106-Temperature sensor, 107-Flow regulating valve, 108-Controller. Detailed Implementation

[0028] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0029] Please see Figure 1 The present invention provides a purification device for aminosulfonic acid, the purification device for aminosulfonic acid includes at least two stages of cooling crystallization units arranged in series, each adjacent two stages of cooling crystallization units are connected by a material conveying pipeline, the inlet of the first stage of the cooling crystallization unit is used to receive the aminosulfonic acid solution to be processed, and the outlet of the last stage of the cooling crystallization unit is used to discharge the crystallized aminosulfonic acid slurry.

[0030] Each stage of the cooling crystallization unit includes a crystallization container 101, a heat exchange component, a disturbance component 102, and a temperature control unit. The heat exchange component is disposed inside the crystallization container 101. The heat exchange component is composed of multiple parallel heat exchange tubes 103. The heat exchange tubes 103 are used to introduce a cooling medium. The disturbance component 102 is also disposed on the crystallization container 101. The disturbance component 102 is used to stir the aminosulfonic acid solution during the crystallization process. The temperature control unit is also disposed on the crystallization container 101. The temperature control unit is used to control the temperature and flow rate of the cooling medium introduced into the heat exchange tubes 103 of the cooling crystallization unit at that stage.

[0031] In this embodiment, the synergistic effect of the multi-stage series-connected cooling crystallization units and their independent temperature control units achieves gradient-based, precise temperature control of the aminosulfonic acid solution, avoiding the problems of uneven grain formation and impurity encapsulation caused by a single rapid cooling mode, thereby improving product purity. Multiple sets of parallel heat exchange tubes 103 significantly increase the effective heat transfer area, and the synergistic stirring of the disturbance component 102 enhances solution turbulence and heat transfer efficiency, greatly shortening the cooling cycle and reducing energy consumption. Simultaneously, the disturbance effectively inhibits crystal adhesion and scaling on the heat exchange surface, and combined with the stable operation of the temperature control unit, significantly extends the continuous production cycle. Using the above structure, high purity is ensured while achieving the goals of efficient, energy-saving, and continuous industrial production.

[0032] Furthermore, the number of cooling crystallization units is preferably three-stage. Through the three-stage series connection of the cooling crystallization units and their corresponding temperature control units, gradient cooling of the aminosulfonic acid solution can be achieved. The gradient cooling includes a first cooling stage, a second cooling stage, and a third cooling stage.

[0033] Specifically, the first cooling stage involves cooling the aminosulfonic acid solution from 80-85°C to 55-60°C, with the cooling rate controlled at 15-20°C / h.

[0034] The second cooling stage specifically involves cooling the aminosulfonic acid solution from 55-60℃ to 30-35℃, with the cooling rate controlled at 10-12℃ / h.

[0035] The third cooling stage specifically involves cooling the aminosulfonic acid solution from 30-35℃ to 10-15℃, with the cooling rate controlled at 5-8℃ / h.

[0036] In this embodiment, a three-stage series cooling crystallization unit is used to decompose the overall cooling process into three stages with different cooling rates, forming a gradient cooling curve that is fast at first and then slows down. The first stage (80-85℃→55-60℃) promotes the formation of an appropriate amount of crystal nuclei; the second stage (55-60℃→30-35℃) provides a stable growth environment for the crystals, allowing them to grow fully and have a regular morphology; the third stage (30-35℃→10-15℃) completes the final crystal growth, maximizing the yield while preventing the formation of fine crystals. This segmented temperature control mode effectively overcomes the problems caused by sudden changes in supersaturation, wide crystal size distribution, and easy encapsulation of impurities caused by single rapid cooling.

[0037] Furthermore, the heat exchange tube 103 in each of the cooling crystallization units is a reinforced heat transfer tube with spiral grooves on the inner wall.

[0038] In this embodiment, the spiral groove structure provided on the inner wall of the heat exchange tube 103 has a dual effect of enhancing heat transfer: on the one hand, the groove increases the inner surface area of ​​the heat exchange tube 103, directly increasing the heat transfer area; on the other hand, the spiral structure can disrupt the laminar flow of the refrigerant in the tube, induce rotating turbulence, significantly thin the heat transfer boundary layer on both sides of the tube wall, thereby greatly improving the convective heat transfer coefficient on the refrigerant side.

[0039] Furthermore, the disturbance component 102 in each of the cooling crystallization units is a rotatable stirring blade, which is located around the corresponding heat exchange tube 103, and the rotation axis of the stirring blade is parallel or perpendicular to the extension direction of the heat exchange tube 103.

[0040] In this embodiment, the rotatable stirring blade serves as a mechanical disturbance component 102, its core function being to force strong convection of the aminosulfonic acid solution within the crystallization container 101. When the blade rotates, it drives the solution to form complex tangential and radial flows around and between the heat exchange tubes 103. This ensures the uniformity of solution temperature and concentration within the container, eliminating localized overcooling or overheating areas and creating conditions for uniform crystal growth. Furthermore, the high-speed flowing liquid exerts a continuous shearing and scouring effect on the outer wall of the heat exchange tubes 103, effectively stripping away the tiny crystal nuclei that have just begun to adhere to the tube wall, preventing their accumulation and growth into a hard scale layer, thereby maintaining the cleanliness of the heat exchange surface and efficient heat transfer.

[0041] Furthermore, each of the cooling crystallization units is also provided with an ultrasonic generator 104, which is located outside the corresponding crystallization container 101 and is used to generate ultrasonic waves into the crystallization container 101.

[0042] In this embodiment, the added ultrasonic generator 104 provides a non-contact physical anti-scaling function. The high-frequency mechanical vibration waves it generates are transmitted into the solution through the container wall, generating instantaneous high-pressure shock waves and high-speed microjets. On the one hand, it can directly act on the surface and near-wall area of ​​the heat exchange tube 103, making it difficult for already attached or soon-to-be-attached crystals to adhere stably, thereby keeping the surface clean. On the other hand, the ultrasonic waves can provide additional energy disturbance throughout the solution, promoting the diffusion of solute molecules, inhibiting crystal aggregation, and facilitating the formation of crystal products with more uniform particle size.

[0043] Furthermore, the purification apparatus for aminosulfonic acid also includes a precooling heat exchanger 105, which is used to precool the aminosulfonic acid solution before it enters the cooling crystallization unit of the first stage using a cooling medium whose temperature has increased from the first stage.

[0044] In this embodiment, the cooling medium discharged from the cooling crystallization unit outside the primary stage, whose temperature has risen (e.g., to 25-30°C) due to absorbing heat from the material, is not directly discarded or entirely returned to the refrigeration unit. Instead, it is first led to the pre-cooling heat exchanger 105 to exchange heat counter-currently with the initially high-temperature (80-85°C) crude aminosulfonic acid solution entering the system. This utilizes waste heat and pre-cools the crude solution to 65-70°C, thereby significantly reducing the heat load on the subsequent main cooling system.

[0045] Furthermore, the precooling heat exchanger 105 is a plate heat exchanger or a shell-and-tube heat exchanger.

[0046] In this embodiment, plate heat exchangers, with their compact structure, extremely high heat transfer efficiency, and ease of disassembly and cleaning, are suitable for handling relatively clean, non-fouling liquid-liquid heat exchange conditions. Shell-and-tube heat exchangers, on the other hand, are characterized by their robust structure, high pressure resistance, and wide applicable temperature and pressure range, making them a reliable choice when heat exchange is required for media with large flow rates or special properties. Both types are mature, efficient, and universal heat exchange equipment, and can be flexibly selected based on specific production scale, site conditions, and investment budget to ensure a stable and efficient cold energy recovery process.

[0047] Furthermore, the temperature control unit in each of the cooling crystallization units consists of a temperature sensor 106, a flow regulating valve 107, and a controller 108 installed on the cooling medium pipeline.

[0048] In this embodiment, the temperature sensor 106 (such as PT100) monitors in real time the temperature of the cooling medium entering the heat exchange tube 103 of this stage and / or the temperature of the material in the crystallization container 101; the flow regulating valve 107 (usually an electric regulating valve) regulates the flow rate of the cooling medium according to the control command; the controller 108 (such as a PID control loop in a PLC or DCS) receives the signal from the temperature sensor 106, compares and calculates it with the preset target temperature or cooling rate set value of this stage, and outputs a control signal to the flow regulating valve 107.

[0049] Please see Figure 2 The present invention also provides a method for purifying aminosulfonic acid, applied to the aminosulfonic acid purification apparatus as described above, comprising the following steps: S1: Provide a crude aminosulfonic acid solution with a concentration of 40-50 wt% and a temperature of 80-85℃; S2: After the purification device for aminosulfonic acid enters continuous steady-state operation, the crude aminosulfonic acid solution is introduced into the precooling heat exchanger 105 to exchange heat with the cooling medium from the cooling crystallization unit outside the first stage, whose temperature has been raised to 25-30°C, so as to precool the crude aminosulfonic acid solution to 65-70°C. S3: The pre-cooled aminosulfonic acid solution is sequentially passed into the three-stage series cooling crystallization unit, and cooling crystallization is carried out in each stage according to the set gradient cooling process; S4: The aminosulfonic acid slurry discharged from the final stage cooling crystallization unit is subjected to solid-liquid separation, washing and drying to obtain aminosulfonic acid crystals, thus completing the purification of aminosulfonic acid.

[0050] In this embodiment, significant cold energy recovery and energy-saving effects are achieved by first efficiently pre-cooling the high-temperature crude solution with the heating refrigerant from the subsequent cooling crystallization unit. Subsequently, a three-stage gradient cooling crystallization process is adopted to complete the formation of crystal nuclei, crystal growth and final crystal growth in stages under precise temperature control. This effectively avoids the problems of uneven crystal particle size and impurity encapsulation caused by traditional quenching processes, thereby stably obtaining high-purity (≥99.9%) aminosulfonic acid. At the same time, by integrating preheating recovery and step-by-step crystallization, this method shortens the cooling cycle, improves production efficiency and reduces energy consumption per unit product, achieving synergistic optimization of high purity, high efficiency and low energy consumption.

[0051] The above description discloses only one preferred embodiment of the present invention, and should not be construed as limiting the scope of the present invention. Those skilled in the art will understand that all or part of the processes of the above embodiments can be implemented, and equivalent changes made in accordance with the claims of the present invention are still within the scope of the invention.

Claims

1. A purification apparatus for aminosulfonic acid, characterized in that, It includes at least two stages of cooling crystallization units connected in series. Each pair of adjacent cooling crystallization units is connected by a material conveying pipeline. The inlet of the first stage cooling crystallization unit is used to receive the aminosulfonic acid solution to be processed, and the outlet of the last stage cooling crystallization unit is used to discharge the crystallized aminosulfonic acid slurry. Each stage of the cooling crystallization unit includes a crystallization container, a heat exchange component, a disturbance component, and a temperature control unit. The heat exchange component is disposed inside the crystallization container. The heat exchange component consists of multiple parallel heat exchange tubes for introducing a cooling medium. The disturbance component is also disposed on the crystallization container for stirring the aminosulfonic acid solution during the crystallization process. The temperature control unit is also disposed on the crystallization container for controlling the temperature and flow rate of the cooling medium introduced into the heat exchange tubes of the cooling crystallization unit at that stage.

2. The apparatus for purifying aminosulfonic acid as described in claim 1, characterized in that, The cooling crystallization unit is preferably three-stage. Through the three-stage series cooling crystallization unit and its corresponding temperature control unit, the gradient cooling of the aminosulfonic acid solution can be achieved. The gradient cooling includes a first cooling stage, a second cooling stage and a third cooling stage. Specifically, the first cooling stage involves cooling the aminosulfonic acid solution from 80-85°C to 55-60°C, with the cooling rate controlled at 15-20°C / h. The second cooling stage specifically involves cooling the aminosulfonic acid solution from 55-60℃ to 30-35℃, with the cooling rate controlled at 10-12℃ / h. The third cooling stage specifically involves cooling the aminosulfonic acid solution from 30-35℃ to 10-15℃, with the cooling rate controlled at 5-8℃ / h.

3. The apparatus for purifying aminosulfonic acid as described in claim 2, characterized in that, The heat exchange tubes in each of the cooling crystallization units are reinforced heat transfer tubes with spiral grooves on the inner wall.

4. The purification apparatus for aminosulfonic acid as described in claim 3, characterized in that, The disturbance component in each of the cooling crystallization units is a rotatable stirring blade located around the corresponding heat exchange tube, with the axis of rotation of the stirring blade parallel or perpendicular to the extension direction of the heat exchange tube.

5. The apparatus for purifying aminosulfonic acid as described in claim 4, characterized in that, Each of the cooling crystallization units is further provided with an ultrasonic generator, which is located outside the corresponding crystallization container and is used to generate ultrasonic waves into the crystallization container.

6. The apparatus for purifying aminosulfonic acid as described in claim 1, characterized in that, The purification apparatus for aminosulfonic acid also includes a precooling heat exchanger, which is used to precool the aminosulfonic acid solution before it enters the cooling crystallization unit of the first stage using a cooling medium whose temperature has increased from that of the cooling crystallization unit outside the first stage.

7. The apparatus for purifying aminosulfonic acid as described in claim 6, characterized in that, The precooling heat exchanger is either a plate heat exchanger or a shell-and-tube heat exchanger.

8. The apparatus for purifying aminosulfonic acid as described in claim 7, characterized in that, The temperature control unit in each of the cooling crystallization units consists of a temperature sensor, a flow regulating valve, and a controller installed on the cooling medium pipeline.

9. A method for purifying aminosulfonic acid, applied to the aminosulfonic acid purification apparatus as described in claim 8, characterized in that, Includes the following steps: Provide a crude aminosulfonic acid solution with a concentration of 40-50 wt% and a temperature of 80-85℃; After the purification device for aminosulfonic acid enters continuous steady-state operation, the crude aminosulfonic acid solution is introduced into the precooling heat exchanger to exchange heat with the cooling medium from the cooling crystallization unit outside the first stage, whose temperature has been raised to 25-30°C, so as to precool the crude aminosulfonic acid solution to 65-70°C. The pre-cooled aminosulfonic acid solution is sequentially passed into the three-stage series cooling crystallization unit, and cooling crystallization is carried out in each stage according to the set gradient cooling process. The aminosulfonic acid slurry discharged from the final stage of the cooling crystallization unit is subjected to solid-liquid separation, washing, and drying to obtain aminosulfonic acid crystals, thus completing the purification of aminosulfonic acid.

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