CN112473168A - Gradient cooling falling film dynamic crystallizer and falling film crystallization separation method of mixture - Google Patents
Gradient cooling falling film dynamic crystallizer and falling film crystallization separation method of mixture Download PDFInfo
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Abstract
The invention aims to solve the problems of the existing dynamic crystallization device, provides a gradient cooling falling film dynamic crystallizer and a falling film crystallization separation method of a mixture, and belongs to the technical field of chemical equipment. The gradient cooling falling film dynamic crystallizer comprises a feeding unit, a falling film crystallization unit and a discharging unit from top to bottom in sequence; the upper part of the feeding unit is a slow flow groove, and the lower part of the feeding unit is a raw material groove; a plurality of film falling pipes are arranged in the falling film crystallization unit, the outer walls of the film falling pipes are sleeved with jacketed pipes, and the side walls of the film falling pipes are provided with circulating water inlets and circulating water outlets; the base of the falling film crystallization unit is fixedly connected with the top of the discharging unit, and a material outlet is arranged on the side wall of the lower part of the falling film crystallization unit. The invention solves the problems of stability and uniformity of materials entering the dynamic crystallizer by arranging the flow slowing groove; the crystallization scale deposition in the initial stage is avoided by improving the uniformity of the material injection on the inner wall of the falling film tube pass; the crystallization efficiency of the tube pass is improved by improving the heat exchange efficiency.
Description
Technical Field
The invention belongs to the technical field of chemical equipment, and particularly relates to purification equipment and a purification method for easily crystallized substances in petrochemical industry and coal chemical industry.
Background
In the production of refined naphthalene, refined anthracene and other products in the petrochemical industry and the coal chemical industry, substances such as thianaphthene, methylindene, phenanthrene and the like have similar boiling points, and the products with higher purity are difficult to obtain by a distillation method, so that the products are prepared by adopting a crystallization method according to the difference of crystallization points by a common method.
At present, more static crystallization process technologies are adopted in China, and the static crystallizer technology mainly comprises the following steps: cooling medium is fed on the tube side, material is fed on the shell side, fins are added on the inner wall of most shell sides to increase the heat exchange area, the material is static after the shell side is filled with the material, the tube side is gradually cooled by the cooling medium, the uncrystallized material is discharged after a certain time, and the purified product is obtained by repeated static crystallization. However, the static crystallization process has problems: the uneven impurity entrainment of non-crystallized materials in the crystallization process is more, the energy consumption is large, the efficiency is low, the quality is not easy to control, and the phenomenon of pipeline blockage occurs due to the fact that the gravity of the shell pass crystallized materials is poor and the crystallized materials fall off and are discharged.
With the market opening of China, the double-falling-film dynamic crystallization technology of Sulshou of Swiss in the last ninety years enters the market of China to be applied by a few large enterprises, and the double-falling-film dynamic crystallization process technology well solves many defects of the static crystallization process technology. The double falling film dynamic crystallization process technology is mainly characterized in that materials flow downwards along the inner pipe wall in a falling film mode on the pipe side, cooling media flow out of the pipe wall, shell side cooling media overflow upwards and flow downwards along the outer pipe wall in a falling film mode, heat is gradually exchanged out to obtain crystals on the inner pipe wall, and the non-uniformity of the temperature in the flowing process when the pipe side is filled with the cooling media can be avoided. However, the problems of the process technology are as follows: the raw materials are pumped into the elevated tank by a pump, and due to the action of the pump pressure, the raw materials enter the raw material tank to generate turbulence, so that the level difference flows downwards to cause fluctuation. The raw material elevated tank is connected with the falling film heat exchange tube pass through a hose, so that the raw material is uniformly distributed to each tube pass for falling film heat exchange, and a certain installation space is required to be reserved between the elevated raw material tank and the falling film heat exchange tube pass through the hose connection, so that material waste is caused. The hose connection still has certain crookedness, can produce the pressure differential difference in the initial stage of production, the inhomogeneous phenomenon of velocity of flow, can bring certain influence for production, and the crookedness of hose also produces the crystallization very easily and blocks up. The cooling medium flows downwards in a falling film mode on the outer wall of the tube pass through overflow, the tube bundle is longer due to the process, generally more than 10 meters, the square cooling balance of the falling film cooling medium is difficult to realize, and the heat exchanged by the cooling heat exchange of the falling film from top to bottom flows downwards in an accumulating mode, so that the phenomenon that the upper portion of crystals in the tube pass is uneven up and down, the upper portion of crystals are thick, the lower portion of crystals are thin, and inverted cones are formed. Both of these factors can greatly reduce production efficiency.
Disclosure of Invention
The invention aims to solve the problems of the conventional dynamic crystallization device and provides a gradient cooling falling film dynamic crystallizer and a falling film crystallization separation method of a mixture. The invention solves the problems of stability and uniformity of materials entering the dynamic crystallizer by arranging the flow slowing groove; the crystallization scale deposition in the initial stage is avoided by improving the uniformity of the material injection on the inner wall of the falling film tube pass; the crystallization efficiency of the tube pass is improved by improving the heat exchange efficiency.
One of the technical schemes of the invention is that a gradient cooling falling film dynamic crystallizer comprises a feeding unit, a falling film crystallization unit and a discharging unit from top to bottom in sequence;
the upper part of the feeding unit is a slow flow groove, and the lower part of the feeding unit is a raw material groove; the upper part of the side wall of the slow flow groove is provided with a material inlet, the bottom of the groove is provided with a plurality of outlets, and a weir plate is arranged around each outlet; the raw material groove is internally provided with a sieve plate, a grid plate and a flange pore plate from top to bottom, the sieve pores of the sieve plate are equidistant holes, a plurality of through holes are uniformly distributed on the flange pore plate, and a plurality of spray pipes are inserted into the through holes;
the falling film crystallization unit is a cavity body which is sealed up and down, a top cover of the cavity body is fixedly connected with a flange hole plate of the feeding unit, a circulating water inlet is arranged at the upper part of the side wall of the cavity body, a circulating water outlet is arranged at the lower part of the side wall of the cavity body, two sealing plates are arranged in the cavity body and are respectively positioned below the circulating water inlet and above the circulating water outlet, a plurality of falling film tubes are arranged in the cavity body, the falling film tubes are respectively opened at the top cover and the base of the cavity body, a spray tube of the feeding unit is inserted into an upper opening corresponding to the falling film tubes, a circular seam is arranged between the spray tube of the falling film unit and the falling film tubes, a clamping sleeve is sleeved on the outer wall of the falling film tubes, the falling film tubes;
preferably, a plurality of cooling water inlets and a cooling water outlet are sequentially arranged on the side wall of the falling film crystallization unit from top to bottom between the upper sealing plate and the lower sealing plate, a sealing fixed partition plate is arranged below each cooling water inlet, the falling film tube and the jacket pipe penetrate through the sealing fixed partition plates, and a gap is arranged between each sealing fixed partition plate and the jacket pipe, so that a secondary cooling cavity is formed among the sealing plates, the inner side of the side wall of the falling film crystallization unit and the outer side of the jacket pipe;
the discharging unit is a cavity with a base, the base of the falling film crystallization unit is fixedly connected with the top of the discharging unit, and a material outlet is formed in the side wall of the lower portion of the falling film crystallization unit.
The second technical scheme of the invention is that the falling film crystallization separation method of the mixture adopts the gradient cooling falling film dynamic crystallizer, and comprises the following steps:
1) opening a circulating water inlet, a circulating water outlet, a cooling water inlet and a cooling water outlet to fill the jacketed pipe and the secondary cooling cavity with cooling media;
2) the mixture material is pumped into the upper end of the slow flow groove by a feeding pump, and overflows inwards from the periphery of the weir plate surrounded by the slow flow groove and enters the raw material groove; the mixture material flows into the grid plate below through the sieve pores of the sieve plate and enters the falling film tube side through a spray pipe arranged on a flange pore plate at the bottom of the grid plate;
3) the insertion depth of the spray pipe is 10-15mm, a 2-5mm circular seam is arranged between the spray pipe and the wall of the falling film tube, the mixture material is sprayed out by utilizing potential difference pressure, the spraying angle is 20-30 degrees, the mixture material is uniformly sprayed on the inner wall of the falling film tube pass in an umbrella shape, and then the mixture material flows downwards in a falling film manner; the tube pass crystallization adopts jacketed pipe falling film cooling heat exchange, in addition, a gap of 3-6 mm is arranged between the sealing fixed clapboard and the jacketed pipe, a cooling medium enters the secondary cooling cavity from a plurality of cooling water inlets and flows downwards along the periphery of the outer pipe wall of the jacketed pipe through the gap to form secondary gradient falling film heat exchange; the mixture is cooled via a falling film tube to crystallize one of the compounds, thereby separating the mixture.
Compared with the prior art, the invention has the advantages that:
1. the invention arranges the raw material groove and the slow chute at the material feeding stage, thereby solving the problem of stability and uniformity of the material before entering the falling film tube pass.
2. The invention is provided with the direct current spray pipe material, the material is sprayed out by the direct current spray pipe and has certain power to ensure that the sprayed material is uniformly sprayed on the inner wall of the falling film pipe pass, and then the falling film type flows downwards, thereby avoiding the deposition of crystal scale at the initial stage of crystallization.
3. The secondary cooling cavity is arranged outside the jacket pipe to form secondary gradient falling film heat exchange, the heat exchanged from top to bottom by the primary falling film heat exchange cooling medium is exchanged for the second time to improve the crystallization efficiency of the pipe pass, and meanwhile, the crystallization process requirements of different temperatures can be realized.
Drawings
FIG. 1 is a schematic view of a crystallizer according to the present invention.
The device comprises a flow-slowing groove 1, a raw material groove 2, a material inlet 3, a falling film crystallization unit 4, a falling film crystallization unit 5, a discharging unit 6, a material outlet 11, a cofferdam plate 21, a grid plate 22, a flange hole plate 23, a spray pipe 41, a falling film pipe 42, a jacketed pipe 43, a circulating water inlet 44, a circulating water outlet 45, an upper sealing plate 46, a lower sealing plate 47, a cooling water inlet 48, a cooling water outlet 49, a sealing fixed partition plate 491 and a secondary cooling cavity.
Detailed Description
Example 1
A gradient cooling falling film dynamic crystallizer comprises a feeding unit, a falling film crystallization unit and a discharging unit from top to bottom in sequence;
the upper part of the feeding unit is a slow flow groove 1, and the lower part of the feeding unit is a raw material groove 2; the upper part of the side wall of the slow flow groove is provided with a material inlet 3, the bottom of the groove is provided with a plurality of outlets, and a weir plate 11 is arranged around each outlet; a sieve plate, a grid plate 21 and a flange pore plate 22 are arranged in the raw material groove from top to bottom, sieve pores of the sieve plate are equidistant, a plurality of through holes are uniformly distributed on the flange pore plate, and a plurality of spray pipes 23 are inserted in the through holes;
the falling film crystallization unit 4 is a cavity body which is sealed up and down, a top cover of the cavity body is fixedly connected with a flange hole plate of the feeding unit, a plurality of falling film tubes 41 are arranged in the cavity body, the number of the falling film tubes is selected according to the treatment amount, the falling film tubes are respectively opened on the top cover and the base of the cavity body, the spray tube 23 is inserted into an upper opening of the corresponding falling film tube, the insertion depth of the spray tube is 10-15mm, a circular seam is arranged between the spray tube and the falling film tubes, the distance between the circular seams is 2-5mm, a clamping sleeve 42 is sleeved on the outer wall of each falling film tube, a circulating water inlet 43 is arranged on the upper portion of the side wall, a circulating water outlet 44 is arranged on the lower portion of the side wall, two sealing plates are arranged in the cavity body and are respectively positioned below the circulating water inlet and above the circulating water outlet, the falling;
a plurality of cooling water inlets 47 and a cooling water outlet 48 are sequentially arranged on the side wall of the falling film unit between the upper sealing plate and the lower sealing plate from top to bottom, a sealing fixed partition plate 49 is arranged below each cooling water inlet, the falling film pipe and the jacket pipe penetrate through the sealing fixed partition plate, a gap is arranged between the sealing fixed partition plate and the jacket pipe, and the gap interval is 3-6 mm, so that a secondary cooling cavity 491 is formed among the sealing plate, the inner side of the side wall of the falling film crystallization unit and the outer side of the jacket pipe;
the discharging unit 5 is a cavity with a base, the base of the falling film crystallization unit is fixedly connected with the top of the discharging unit, and a material outlet 6 is arranged on the side wall of the lower part of the falling film crystallization unit.
The falling film crystallization separation method of the mixture adopts the gradient cooling falling film dynamic crystallizer of the embodiment, and comprises the following steps:
1) opening a circulating water inlet, a circulating water outlet, a cooling water inlet and a cooling water outlet to fill the jacketed pipe and the secondary cooling cavity with cooling media;
2) the mixture material is pumped into the upper end of the slow flow groove by a feeding pump, and overflows inwards from the periphery of the weir plate surrounded by the slow flow groove and enters the raw material groove; the mixture material flows into the grid plate below through the equidistant holes of the sieve plate and enters a falling film tube side through a spray pipe arranged on a flange hole plate at the bottom of the grid plate; the main purpose is to solve the problems of stability and uniformity of materials;
3) the insertion depth of the spray pipe is 10-15mm, a 2-5mm circular seam is arranged between the spray pipe and the wall of the falling film pipe, the mixture material is sprayed out by utilizing potential difference pressure, the spraying angle is 20-30 degrees, the mixture material is uniformly sprayed on the inner wall of the falling film pipe in an umbrella shape and then flows downwards in a falling film mode, certain power is provided when the material is sprayed out through the direct-current spray pipe, and the crystal scale accumulation in the initial stage is better avoided; the mixture is cooled via a falling film tube to crystallize one of the compounds, thereby separating the mixture.
The tube pass crystallization mainly adopts falling film cooling heat exchange, and a jacketed pipe controls the uniformity of flow velocity and heat exchange area during falling film; a gap of 3-6 mm is arranged between the sealing fixed partition plate and the jacket pipe, a cooling medium enters the secondary cooling cavity through a plurality of cooling water inlets, and flows downwards along the periphery of the outer pipe wall of the jacket pipe through the gap to form secondary gradient falling film heat exchange, heat exchanged by the primary falling film heat exchange cooling medium is exchanged for the second time, the crystallization efficiency of a pipe pass is improved, and the crystallization process requirements of different temperatures can be met.
Claims (6)
1. A gradient cooling falling film dynamic crystallizer is characterized in that a feeding unit, a falling film crystallization unit and a discharging unit are sequentially arranged from top to bottom;
the upper part of the feeding unit is a slow flow groove, and the lower part of the feeding unit is a raw material groove; the upper part of the side wall of the slow flow groove is provided with a material inlet, the bottom of the groove is provided with a plurality of outlets, and a weir plate is arranged around each outlet; the raw material groove is internally provided with a sieve plate, a grid plate and a flange pore plate from top to bottom, a plurality of through holes are uniformly distributed on the flange pore plate, and a plurality of spray pipes are inserted into the through holes;
the falling film crystallization unit is a cavity body which is sealed up and down, a top cover of the cavity body is fixedly connected with a flange hole plate of the feeding unit, a circulating water inlet is arranged at the upper part of the side wall of the cavity body, a circulating water outlet is arranged at the lower part of the side wall of the cavity body, two sealing plates are arranged in the cavity body and are respectively positioned below the circulating water inlet and above the circulating water outlet, a plurality of falling film tubes are arranged in the cavity body, the falling film tubes are respectively opened at the top cover and the base of the cavity body, a spray pipe of the feeding unit is inserted into an upper opening corresponding to the falling film tubes, a clamping sleeve is sleeved on the outer wall of each falling film tube, the falling film tubes penetrate through the upper sealing plate;
the discharging unit is a cavity with a base, the base of the falling film crystallization unit is fixedly connected with the top of the discharging unit, and a material outlet is formed in the side wall of the lower portion of the falling film crystallization unit.
2. The gradient cooling falling film dynamic crystallizer of claim 1, wherein the screen holes of the screen plates are equidistant holes.
3. The gradient cooling falling film dynamic crystallizer of claim 1, wherein a circular seam is arranged between a spray pipe and a falling film pipe of the falling film unit.
4. The gradient cooling falling film dynamic crystallizer of claim 1, wherein a plurality of cooling water inlets and a cooling water outlet are arranged on the side wall of the falling film unit from top to bottom between the upper and lower sealing plates, a sealing fixed partition plate is arranged below each cooling water inlet, the falling film tube and the jacket tube pass through the sealing fixed partition plate, and a gap is arranged between the sealing fixed partition plate and the jacket tube, so that a secondary cooling cavity is formed between the sealing plate, the inner side of the side wall of the falling film crystallization unit and the outer side of the jacket tube.
5. A falling film crystallization separation method of a mixture, which adopts the gradient temperature reduction falling film dynamic crystallizer of any one of claims 1 to 4, and is characterized by comprising the following steps:
1) opening a circulating water inlet, a circulating water outlet, a cooling water inlet and a cooling water outlet to fill the jacketed pipe and the secondary cooling cavity with cooling media;
2) the mixture material is pumped into the upper end of the slow flow groove by a feeding pump, and overflows inwards from the periphery of the weir plate surrounded by the slow flow groove and enters the raw material groove; the mixture material flows into the grid plate below through the sieve pores of the sieve plate and enters the falling film tube side through a spray pipe arranged on a flange pore plate at the bottom of the grid plate;
3) the mixture material is sprayed out by utilizing potential difference pressure, uniformly sprayed on the inner wall of the falling film pipe in an umbrella shape, and then flows downwards in a falling film manner; the tube pass crystallization adopts jacketed pipe falling film cooling heat exchange, in addition, a gap is arranged between the sealing fixed clapboard and the jacketed pipe, a cooling medium enters the secondary cooling cavity from a plurality of cooling water inlets and flows downwards along the periphery of the outer pipe wall of the jacketed pipe through the gap to form secondary gradient falling film heat exchange; the mixture is cooled via a falling film tube to crystallize one of the compounds, thereby separating the mixture.
6. The falling film crystallization separation method of mixtures according to claim 5, characterized in that in step 3), the mixture material is sprayed at a spray angle of 20-30 °.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202110016680.6A CN112473168A (en) | 2021-01-07 | 2021-01-07 | Gradient cooling falling film dynamic crystallizer and falling film crystallization separation method of mixture |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114191843A (en) * | 2022-01-14 | 2022-03-18 | 上海东庚化工技术有限公司 | Efficient continuous falling film melting crystallizer |
| CN114768294A (en) * | 2022-06-21 | 2022-07-22 | 河北纽思泰伦环保科技有限公司 | Continuous crystallization system of thiourea |
-
2021
- 2021-01-07 CN CN202110016680.6A patent/CN112473168A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114191843A (en) * | 2022-01-14 | 2022-03-18 | 上海东庚化工技术有限公司 | Efficient continuous falling film melting crystallizer |
| WO2023134233A1 (en) * | 2022-01-14 | 2023-07-20 | 上海东庚化工技术有限公司 | Continuous falling film melting crystallizer |
| CN114768294A (en) * | 2022-06-21 | 2022-07-22 | 河北纽思泰伦环保科技有限公司 | Continuous crystallization system of thiourea |
| CN114768294B (en) * | 2022-06-21 | 2022-08-30 | 河北纽思泰伦环保科技有限公司 | Continuous crystallization system of thiourea |
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