A system for removing impurities for carbazide production
By designing a multi-stage filtration and adsorption system for impurity removal, the problem of impurity removal in the production of carbazine was solved, and the production of high-purity carbazine was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- WEIFANG YUKAI CHEM
- Filing Date
- 2025-07-28
- Publication Date
- 2026-07-14
AI Technical Summary
Existing technologies have difficulty effectively removing metal ions and organic impurities in the production of carbazide, resulting in low product purity.
An impurity removal system was designed, including an evaporator, a filter, a precipitation vessel, an adsorption device, and a crystallization vessel. Impurities in carbazide are removed through a multi-stage filtration and adsorption process, and a multi-step purification is carried out using an ultrafiltration membrane, a cation exchange resin column, and an anion exchange resin column.
This method achieves efficient separation and purification of carbazine, significantly improving the purity of the product.
Smart Images
Figure CN224485250U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of carbazide production technology, and in particular to a purification system for carbazide production. Background Technology
[0002] Carbazine is a widely used chemical in the chemical industry, encompassing various types such as carbazine hydrochloride and diphenylcarbazine. Currently, industrial production technologies for carbazine are quite mature, primarily including the urea process, dimethyl carbonate process, and phosgene process. The urea process utilizes readily available and relatively inexpensive raw materials, urea and hydrazine hydrate, and offers relatively mild and controllable reaction conditions. However, in actual production, due to the presence of metal ions and organic impurities in the raw materials and byproducts of the synthesis process, most existing technologies employ crystallization to remove these impurities, resulting in low product purity. Therefore, it is necessary to develop an impurity removal system for carbazine to address these issues. Utility Model Content
[0003] The technical problem to be solved by this utility model is to provide a purification system for the production of carbazine, which can effectively remove impurities from carbazine and greatly improve the purity of carbazine, in order to address the shortcomings of the existing technology.
[0004] To solve the above-mentioned technical problems, the technical solution of this utility model is as follows:
[0005] A purification system for carbazide production includes an evaporator, the outlet of which is connected to a first filter, the outlet of which is connected to a sedimentation tank, the outlet of which is connected to a second filter, the outlet of which is connected to a sediment storage tank, the outlet of which is connected to a first adsorption device, the outlet of which is connected to a cation exchange resin column, the outlet of which is connected to an anion exchange resin column, the outlet of which is connected to a second adsorption device, the outlet of which is connected to a crystallization tank, the crystal outlet of which is connected to a drying device, and the outlet of which is connected to a product storage tank.
[0006] As an improved technical solution, the evaporator includes a vessel body, with a feed inlet and an vent at the top and a discharge outlet at the bottom; the vessel body is provided with a jacket on the outside and a rotating shaft inside the vessel body, one end of the rotating shaft is connected to a motor, and multiple stirring rods are provided on the rotating shaft, with multiple stirring blades on the stirring rods.
[0007] As an improved technical solution, the first filtration device is an ultrafiltration membrane device with a molecular weight cutoff of 1000-100000 Da.
[0008] As an improved technical solution, the precipitation vessel includes a vessel body, with a feed inlet and an oxalic acid solution inlet at the top of the vessel body and a discharge outlet at the bottom of the vessel body; a rotating shaft is provided inside the vessel body, one end of the rotating shaft is connected to a motor, a stirring frame is provided on the rotating shaft, and multiple stirring plates are provided on the stirring frame.
[0009] As an improved technical solution, the second filtration device is a plate and frame filter press.
[0010] As an improved technical solution, the first adsorption device includes a body, with a feed inlet at the top and a discharge outlet at the bottom. The body has a zeolite adsorption layer inside and an alumina adsorption layer below the zeolite adsorption layer.
[0011] As an improved technical solution, the second adsorption device includes a body, with a feed inlet at the top and a discharge outlet at the bottom, and an activated carbon adsorption layer and a silica gel adsorption layer inside the body.
[0012] As an improved technical solution, the crystallization vessel includes a vessel body, with a feed inlet and a crystal outlet at the top and bottom of the vessel body, respectively, and a liquid outlet on one side of the lower part of the vessel body. A filter screen is provided inside the vessel body at a position corresponding to the liquid outlet. A jacket is provided outside the vessel body, and a rotating shaft is provided inside the vessel body. One end of the rotating shaft is connected to a motor, and multiple stirring plates are provided on the rotating shaft.
[0013] After adopting the above technical solution, the beneficial effects of this utility model are:
[0014] The impurity removal system used in the production of carbazine includes an evaporator, the outlet of which is connected to a first filter, the outlet of which is connected to a sedimentation tank, the outlet of which is connected to a second filter, the outlet of which is connected to a sediment storage tank, the outlet of which is connected to a first adsorption device, the outlet of which is connected to a cation exchange resin column, the outlet of which is connected to an anion exchange resin column, the outlet of which is connected to a second adsorption device, the outlet of which is connected to a crystallization tank, the crystal outlet of which is connected to a drying device, and the outlet of which is connected to a product storage tank. In actual production, the synthesized carbazide solution is pumped into an evaporator to remove free water and some low-boiling-point impurities (such as free hydrazine). The evaporated solution then enters the first filtration unit to remove mechanical impurities and particulate byproducts. The filtered liquid is then pumped into a precipitation tank where it reacts with oxalic acid solution, causing iron and copper ions to precipitate. The precipitate then enters the second filtration unit, where it is pumped into the first adsorption unit to remove some water, small-molecule organic impurities, and pigments. It then enters a cation exchange resin column for further removal of metal ions, followed by an anion exchange resin column for anion removal. The solution then enters the second adsorption unit, where the adsorption material further removes pigments and small-molecule impurities. Finally, the purified solution is pumped into a crystallization tank, where the collected crystals are cooled and dried to obtain high-purity carbazide, which is then stored in a product storage tank. The above-mentioned production system is reasonably designed and achieves the separation of impurities and carbazine, which greatly improves the purity of carbazine.
[0015] The evaporator consists of a vessel body with a feed inlet and an outlet at the top and a discharge outlet at the bottom. The vessel body is fitted with a jacket, and a rotating shaft is located inside. One end of the shaft is connected to a motor, and multiple stirring rods with impurities are mounted on the shaft. The carbazide solution containing impurities enters the vessel body via a pump. The solution is heated by a heat transfer medium in the jacket. After the motor starts, the electric rotating shaft, along with the stirring rods and impurities, stirs and mixes the solution, ensuring uniform heating. This facilitates the discharge of free water and low-boiling-point small-molecule organic impurities through the outlet, achieving initial impurity removal from the solution.
[0016] The first filtration device is an ultrafiltration membrane with a molecular weight cutoff of 1000-100000 Da, which can effectively remove mechanical impurities and particulate byproducts.
[0017] The precipitation vessel consists of a vessel body with a feed inlet and an oxalic acid solution inlet at the top and a discharge outlet at the bottom. Inside the vessel body is a rotating shaft, one end of which is connected to a motor. A stirring frame with multiple stirring plates is mounted on the shaft. In actual production, carbazide solution containing metal ions is pumped into the vessel body, and oxalic acid solution is added. Once the motor starts, it drives the rotating shaft, stirring frame, and stirring plates to rotate, promoting full contact and reaction between the oxalic acid solution and the metal ions in the carbazide solution, facilitating precipitate formation and thus achieving separation from the carbazide solution.
[0018] The second filtration device is a plate and frame filter press, which facilitates the effective separation of ferric oxalate and copper oxalate precipitates from the feed solution containing carbazine.
[0019] The first adsorption device includes a main body with a feed inlet at the top and a discharge outlet at the bottom. The interior of the main body contains a zeolite adsorption layer, and below the zeolite adsorption layer is an alumina adsorption layer. The zeolite adsorption layer enables the adsorption of small-molecule volatile impurities (such as hydrazine and ammonia), while the alumina adsorption layer enables the adsorption of colored impurities, thereby improving the purity of carbazide.
[0020] The second adsorption device includes a main body with an inlet at the top and an outlet at the bottom. The interior of the main body contains an activated carbon adsorption layer and a silica gel adsorption layer. The activated carbon adsorption layer further adsorbs pigment impurities and polar impurities, while the silica gel adsorption layer adsorbs polar impurities, thereby improving the purity of carbazine.
[0021] The crystallization vessel comprises a vessel body with a feed inlet at the top and a crystal outlet at the bottom, and a liquid outlet on one side of the lower part of the vessel body. A filter screen is installed inside the vessel body corresponding to the liquid outlet. The vessel body is equipped with a jacket, and a rotating shaft is located inside, with one end connected to a motor and multiple stirring plates mounted on the shaft. The feed solution containing carbazine enters the vessel body and is cooled to the crystallization temperature by a refrigerant in the jacket. After the motor starts, it drives the rotating shaft and multiple stirring plates to stir the feed solution, promoting uniform cooling and greatly improving crystallization efficiency. Uncrystallized impurities in the mother liquor are extracted through the filter screen by a suction pump. This crystallization vessel design is reasonable, achieving effective crystallization of carbazine while also separating carbazine from impurities. Attached Figure Description
[0022] Figure 1 This is a schematic diagram of the structure of a purification system for the production of carbazide according to this utility model;
[0023] Among them, 1-evaporation kettle, 2-first filtration device, 3-precipitation kettle, 4-second filtration device, 5-first adsorption device, 50-zeolite adsorption layer, 51-alumina adsorption layer, 6-cation exchange resin column, 7-anion exchange resin column, 8-second adsorption device, 80-activated carbon adsorption layer, 81-silica gel adsorption layer, 9-crystallization kettle, 10-drying device, 11-product storage tank. Detailed Implementation
[0024] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.
[0025] A purification system for carbazide production, such as Figure 1 As shown, the system includes an evaporator 1, the outlet of which is connected to a first filtration device 2 (an ultrafiltration membrane device with a molecular weight cutoff of 1000-100000 Da), the outlet of the first filtration device 2 is connected to a sedimentation tank 3, the outlet of the sedimentation tank 3 is connected to a second filtration device 4 (a plate and frame filter), the outlet of the second filtration device 4 is connected to a first adsorption device 5, the outlet of the second filtration device is connected to a precipitate storage tank 12, the outlet of the first adsorption device 5 is connected to a cation exchange resin column 6 (a strong acidic cation exchange resin - D001), the outlet of the cation exchange resin column 6 is connected to an anion exchange resin column 7 (a strong basic macroporous anion exchange resin - D201), the outlet of the anion exchange resin column 7 is connected to a second adsorption device 8, the outlet of the second adsorption device 8 is connected to a crystallization tank 9, the crystal outlet of the crystallization tank 9 is connected to a drying device 10 (a double cone dryer), and the outlet of the drying device 10 is connected to a product storage tank 11.
[0026] In actual production, the prepared carbazide solution containing impurities is pumped into an evaporation kettle. After evaporation, free water and some low-boiling-point impurities (such as free hydrazine) are removed. The evaporated solution then enters the first filtration unit to remove mechanical impurities and particulate byproducts. The filtered liquid is then pumped into a precipitation kettle, where it reacts with oxalic acid solution to form a precipitate of iron and copper ions. The precipitate then enters the second filtration unit. The treated precipitate is stored in a precipitate storage tank, and the treated liquid is pumped into… Inside the first adsorption unit, some moisture, small-molecule organic impurities, and pigments are removed. The solution then enters a cation exchange resin column for further removal of metal ions, followed by an anion exchange resin column for anion removal. The solution then enters the second adsorption unit, where the adsorption material further removes pigments and small-molecule impurities. Finally, the purified solution is pumped into a crystallization kettle, where the collected crystals are collected and transported by conveyor belt to a drying unit for further drying, yielding high-purity carbazine. This high-purity product is then stored in a product storage tank. This production system is rationally designed and effectively separates impurities from carbazine, significantly improving the purity of carbazine.
[0027] The evaporation vessel 1 includes a vessel body with a feed inlet and an exhaust outlet at the top and a discharge outlet at the bottom. The vessel body is fitted with a jacket, and a rotating shaft is located inside. One end of the shaft is connected to a motor, and multiple stirring rods with impurities are mounted on the shaft. The carbazide solution containing impurities enters the vessel body via a pump. The solution is heated by a heat transfer medium in the jacket. After the motor starts, the electric rotating shaft, along with the stirring rods and impurities, stirs and mixes the solution, ensuring uniform heating. This facilitates the discharge of free water and low-boiling-point small-molecule organic impurities through the exhaust outlet, achieving initial impurity removal from the solution.
[0028] The precipitation vessel 3 includes a vessel body with a feed inlet and an oxalic acid solution inlet at the top and a discharge outlet at the bottom. Inside the vessel body is a rotating shaft, one end of which is connected to a motor. A stirring frame with multiple stirring plates is mounted on the shaft. In actual production, carbazide solution containing metal ions enters the vessel body via a pump, and oxalic acid solution is added. After the motor starts, it drives the rotating shaft, stirring frame, and multiple stirring plates to rotate, promoting full contact and reaction between the oxalic acid solution and the metal ions in the carbazide solution, facilitating the formation of a precipitate and thus achieving separation from the carbazide solution.
[0029] The first adsorption device 5 includes a main body with an inlet at the top and an outlet at the bottom. Inside the main body is a zeolite adsorption layer 50, and below the zeolite adsorption layer is an alumina adsorption layer 51. The zeolite adsorption layer enables the adsorption of small-molecule volatile impurities (such as hydrazine and ammonia), while the alumina adsorption layer enables the adsorption of colored impurities, thereby improving the purity of carbazide.
[0030] The second adsorption device 8 includes a main body with an inlet at the top and an outlet at the bottom. The interior of the main body contains an activated carbon adsorption layer 80 and a silica gel adsorption layer 81. The activated carbon adsorption layer further adsorbs pigment impurities and polar impurities, while the silica gel adsorption layer adsorbs polar impurities, thereby improving the purity of carbazine.
[0031] The crystallization vessel 9 includes a vessel body with a feed inlet at the top and a crystal outlet at the bottom, and a liquid outlet on one side of the lower part of the vessel body. A filter screen is installed inside the vessel body corresponding to the liquid outlet. The vessel body is equipped with a jacket, and a rotating shaft is located inside the vessel body. One end of the rotating shaft is connected to a motor, and multiple stirring plates are mounted on the rotating shaft. The feed solution containing carbazine enters the vessel body and is cooled to the crystallization temperature by a refrigerant in the jacket. After the motor starts, it drives the rotating shaft and multiple stirring plates to stir the feed solution, promoting uniform cooling and greatly improving crystallization efficiency. Uncrystallized impurities in the mother liquor are extracted through the filter screen by a suction pump. The crystallization vessel with the above structure is rationally designed, achieving effective crystallization of carbazine and separating carbazine from impurities.
[0032] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.
Claims
1. A purification system for the production of carbazine, characterized in that, The apparatus includes an evaporator, the outlet of which is connected to a first filtration device, the outlet of which is connected to a sedimentation tank, the outlet of which is connected to a second filtration device, the outlet of which is connected to a sediment storage tank, the outlet of which is connected to a first adsorption device, the outlet of which is connected to a cation exchange resin column, the outlet of which is connected to an anion exchange resin column, the outlet of which is connected to a second adsorption device, the outlet of which is connected to a crystallization tank, the crystal outlet of which is connected to a drying device, and the outlet of which is connected to a product storage tank.
2. The impurity removal system for carbazide production according to claim 1, characterized in that, The evaporation vessel includes a vessel body, with a feed inlet and an vent at the top and a discharge outlet at the bottom. The vessel body is fitted with a jacket on the outside and a rotating shaft inside. One end of the rotating shaft is connected to a motor, and multiple stirring rods are mounted on the rotating shaft, with multiple stirring blades on each stirring rod.
3. The impurity removal system for carbazide production according to claim 1, characterized in that, The first filtration device is an ultrafiltration membrane device with a molecular weight cutoff of 1000-100000 Da.
4. The impurity removal system for carbazide production according to claim 1, characterized in that, The precipitation vessel includes a vessel body, with a feed inlet and an oxalic acid solution inlet at the top of the vessel body and a discharge outlet at the bottom of the vessel body; a rotating shaft is provided inside the vessel body, one end of the rotating shaft is connected to a motor, a stirring frame is provided on the rotating shaft, and multiple stirring plates are provided on the stirring frame.
5. The impurity removal system for carbazide production according to claim 1, characterized in that, The second filtration device is a plate and frame filter press.
6. The impurity removal system for carbazide production according to claim 1, characterized in that, The first adsorption device includes a body, with a feed inlet at the top and a discharge outlet at the bottom. The body has a zeolite adsorption layer inside and an alumina adsorption layer below the zeolite adsorption layer.
7. The impurity removal system for carbazide production according to claim 1, characterized in that, The second adsorption device includes a body, with an inlet at the top and an outlet at the bottom. The body contains an activated carbon adsorption layer and a silica gel adsorption layer.
8. The impurity removal system for carbazide production according to claim 1, characterized in that, The crystallization vessel includes a vessel body, with a feed inlet and a crystal outlet at the top and bottom of the vessel body, respectively. A liquid outlet is provided on one side of the lower part of the vessel body, and a filter screen is provided inside the vessel body at a position corresponding to the liquid outlet. A jacket is provided on the outside of the vessel body, and a rotating shaft is provided inside the vessel body. One end of the rotating shaft is connected to a motor, and multiple stirring plates are provided on the rotating shaft.