CN210845344U

CN210845344U - Integrated crystallization device with continuous fine grain elimination circulation

Info

Publication number: CN210845344U
Application number: CN201921051581.6U
Authority: CN
Inventors: 夏君君; 于会满; 尹海蛟; 全晓宇; 刘莉; 谢源圩
Original assignee: Tianjin Leke Energy Saving Technology Co ltd
Current assignee: Tianjin Leke Energy Saving Technology Co ltd
Priority date: 2019-07-08
Filing date: 2019-07-08
Publication date: 2020-06-26
Anticipated expiration: 2029-07-08

Abstract

The utility model discloses an integration crystallization device with circulation is eliminated to continuous fine grain has solved that the fine grain of current extrinsic cycle type eliminates the crystallization system structure complicacy, and equipment investment is high, and the operation interval is narrow, and circulating flow field skew reaches fine grain and eliminates the poor scheduling problem of effect. The utility model discloses an inside fine grain of setting up of traditional DTB or Oslo type crystallizer and eliminating circulation heat transfer device, realized the fine grain and eliminated the integrated design of circulation system and crystallizer. The circulation flow of the crystallization mother liquor is improved by optimizing the internal structure of the crystallizer, so that crystals are suspended in a liquid flow to form a fluidized bed with graded particle size. The crystals with larger granularity are enriched and continue to grow in the crystal growth area at the bottom of the crystallizer, and the crystals with smaller granularity are heated and dissolved through the fine grain elimination circulation area along with ascending liquid flow, so that fine grains are effectively removed. The application discloses integration crystallization device has equipment structure compactness reliable, and fine grain elimination effect is good, advantages such as product particle size distribution is controllable.

Description

Integrated crystallization device with continuous fine grain elimination circulation

Technical Field

The utility model belongs to the technical field of the crystallization, concretely relates to integration crystallization device with continuous fine grain elimination cycle (CFDC)

Background

Crystallization is an important unit operation in the chemical production process, and numerous chemical products exist in a crystal form. The crystallization process is not only used in the production process of products, but also widely used in the separation and purification processes of products. Compared with other unit operations such as rectification and the like, the crystallization process has the advantages of low operation temperature, suitability for thermosensitive substances, low process energy consumption, high purity of obtained products and the like.

From the viewpoints of product purity, product fluidity, easy separation during production, and the like, the crystallization process usually seeks to obtain a crystal product with a larger particle size and uniform distribution. The particle size distribution of the product of the crystallization process is mainly influenced by the nucleation rate and the crystal growth rate, wherein the nucleation rate is the most important reason for influencing the particle size distribution of the crystallized product. The supersaturation degree of the crystallization mother liquor can be adjusted by adjusting the operating parameters of the crystallization process to control the nucleation rate of the crystallization process and optimize the particle size distribution of the product. However, the method is sometimes limited by other requirements of the crystallization process, and the nucleation rate cannot be effectively controlled by adjusting corresponding operating parameters, so that a large number of fine crystal nuclei are generated in the crystallization process, and the final crystal product has a small average particle size and a wide particle size distribution range. For the crystallization process which can not effectively control the nucleation rate, a fine crystal elimination mode is usually adopted to eliminate excessive fine crystal nuclei generated in the nucleation process, so that solute in the crystallization mother liquor is concentrated on the surface of a small amount of large crystal grains to continue to grow, and thus, a crystal product with large average particle size and uniform particle size distribution is obtained. In the prior art, the mode of external circulation is usually adopted for eliminating fine crystals, mother liquor containing fine crystals in a crystallizer is pumped out of the crystallizer, heat exchange is carried out through a heat exchanger to dissolve the fine crystals, and then the mother liquor returns to the crystallizer again through a circulating pump. For example, patents CN93101419.0, CN200510013414.9, CN200810154636.6, CN201010262062.1 and US3873275A all describe crystallizers with external circulation type fine crystal elimination systems. The whole external circulation fine grain elimination system is generally composed of a circulating pump, a heat exchanger and a circulating pipeline, and has the defects of large equipment investment, complex structure, large occupied area and the like. Meanwhile, crystallization mother liquor containing fine crystals is pumped out of the crystallizer through a circulating pipeline, an outlet of the crystallization mother liquor can be only arranged on a certain point of the circumference of the crystallizer, and the defects of flow field deviation and unsatisfactory pumping effect exist naturally. Meanwhile, the external circulation type fine grain elimination system is limited by heat exchange temperature difference, a large circulation amount is often needed, the operation energy consumption of equipment is improved, and the excessive circulation amount easily causes the internal flow field of the crystallizer to form a complete mixing state, so that the real fine grain elimination circulation cannot be realized. The integrated crystallization device and crystallization method with continuous fine crystal elimination cycle are not reported.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to overcome prior art's not enough, provide an integration crystallization device with continuous fine grain elimination cycle.

The utility model discloses a realize through following technical scheme:

an integrated crystallizing device with continuous fine grain eliminating circulation is characterized by comprising a feed inlet, a discharge outlet, a vaporizing chamber, a fine grain eliminating circulation area and a crystal growth area, wherein a guide cylinder or a downcomer is arranged in the device, and a fine grain eliminating heat exchange device is arranged between the outer wall of the guide cylinder or the downcomer and the inner wall of the device in the fine grain eliminating circulation area.

In the technical scheme, the fine grain elimination heat exchange device is a heat exchange coil or a heat exchange plate, two or more circles of circumference distribution are formed between the outer wall of the guide cylinder or the downcomer and the inner wall of the device, and a fine grain elimination circulation channel is formed between the circles of heat exchange devices at certain intervals.

In the technical scheme, the crystallization device is also provided with a stirrer, the stirrer is in a paddle type stirring mode, and the paddle extends into the lower end of the inner part of the guide cylinder or the downcomer.

In the above technical scheme, the crystal growth region of the crystallization device is conical, and the bottom of the crystallization device is W-shaped.

In the technical scheme, the feeding hole is positioned at the upper part of the crystallization device and extends to the axis of the guide shell or the downcomer for feeding downwards, and the discharging hole is positioned at the bottom of the crystallization device.

In the above technical scheme, the crystallization device top is equipped with steam outlet, and steam outlet links to each other with the steam compressor entry, and the steam compressor export links to each other with condenser gas side import, and condenser gas side export links to each other with the jar entry of congealing, and the jar export of congealing even has the vacuum pump to be used for discharging noncondensable gas.

In the above technical solution, the vapor compressor is a roots compressor, a centrifugal compressor or a screw compressor.

The utility model discloses an advantage and beneficial effect do:

the utility model discloses an inside fine grain of setting up of traditional DTB or Oslo type crystallizer and eliminating circulation heat transfer device, at the inside continuous fine grain of formation elimination circulation of crystallizer, realized the fine grain and eliminated the integrated design of circulation system and crystallizer. The circulation flow of the crystallization mother liquor is improved by optimizing the internal structure of the crystallizer, so that crystals are suspended in a liquid flow to form a fluidized bed with graded particle size. The crystals with larger granularity are enriched and continue to grow in the crystal growth area at the bottom of the crystallizer, and the crystals with smaller granularity are heated and dissolved through the fine grain elimination circulation area along with ascending liquid flow, so that fine grains are effectively removed. Adopt the utility model discloses an integrated crystallization device with continuous fine grain elimination circulation can initiatively regulate and control product particle size distribution when carrying out crystallization production. The fine-grain elimination circulating heat exchange devices are circumferentially distributed around the central axis of the crystallizer, so that the fine-grain elimination circulating channels are uniformly distributed in a centrosymmetric manner, and the problem of flow field offset existing when the traditional fine-grain elimination circulating system extracts mother liquor is solved. Meanwhile, the optimization of an internal flow field is benefited, the fine grain circulation efficiency is improved, and the design of equipment integration overcomes the defects of complex structure, high investment of matched equipment, poor stability, large floor area, large circulation amount, high operation cost and the like of an external circulation type fine grain elimination circulation system in the prior art.

Drawings

FIG. 1 is a schematic view of a conventional crystallization system for removing fine crystals by external circulation.

In the figure: 1-crystallizer, 2-heat exchanger, 3-circulating pump.

FIG. 2 is an integrated crystallization device with a continuous fine grain elimination cycle with a draft tube structure inside.

In the figure: 1-feeding inlet, 2-discharging outlet, 3-vaporizing chamber, 4-fine grain elimination circulation zone, 5-crystal growth zone, 6-guide shell and 7-fine grain elimination heat-exchange device.

FIG. 3 is an integrated crystallization device with a continuous fine grain elimination cycle with internal downcomer structure.

In the figure: 1-feeding inlet, 2-discharging outlet, 3-vaporizing chamber, 4-fine crystal elimination circulation zone, 5-crystal growth zone, 6-down spout and 7-fine crystal elimination heat exchange device.

Detailed Description

In order to make the technical field of the present invention better understand, the technical solutions of the present invention are further described below with reference to the accompanying drawings and specific embodiments.

Example 1

Adopting three device forms of a CFDC integrated crystallization device with a guide flow cylinder structure inside and a traditional DTB type crystallization device as shown in figure 2 and an external fine grain elimination heat exchanger of the traditional DTB type crystallization device respectively, carrying out a pilot test experiment of cobalt chloride continuous crystallization by a vacuum flash evaporation cooling crystallization method, controlling the feeding concentration of the cobalt chloride to be 300g/L (Co ion concentration), the feeding temperature to be 70 ℃, and the feeding amount to be 0.3m³And h, controlling the circulation ratio R of the fine grain elimination stream to be 2.5 for a crystallization device externally connected with a fine grain elimination heat exchanger, controlling the temperature of the fine grain elimination heat exchange device to be 35 ℃, controlling the crystallization temperature to be 33 ℃, controlling the retention time to be 3h, sampling after the system stabilization time is 30h, and carrying out particle size analysis, wherein the result is shown in table 1.

TABLE 1 particle size analysis for cobalt chloride crystallization experiments

Example 2

Adopting three device forms of a CFDC integrated crystallization device with a guide flow cylinder structure inside and a traditional DTB type crystallization device as shown in figure 2 and an external fine grain elimination heat exchanger of the traditional DTB type crystallization device respectively, carrying out a pilot test experiment of continuous crystallization of cobalt sulfate by a vacuum flash evaporation cooling crystallization method, controlling the feeding concentration of the cobalt sulfate to be 240g/L (Co ion concentration), the feeding temperature to be 80 ℃, and the feeding amount to be 0.3m³And h, controlling the circulation ratio R of the fine grain elimination stream to be 2.5 for a crystallization device externally connected with the fine grain elimination heat exchanger, controlling the temperature of the fine grain elimination heat exchange device to be 43 ℃, controlling the crystallization temperature to be 40 ℃, controlling the retention time to be 3h, sampling after the system stabilization time is 30h, and carrying out particle size analysis, wherein the result is shown in table 2.

TABLE 2 particle size analysis of cobalt sulfate crystallization experiment

Example 3

Adopting CFDC integrated crystallization device and traditional Oslo type crystallization device with downcomer structure as shown in figure 3, respectively, performing pilot-scale experiment of vitamin C continuous crystallization by vacuum flash evaporation cooling crystallization method, controlling vitamin C feeding concentration at 50 wt%, feeding temperature at 60 deg.C, and feeding amount at 0.3m³And h, controlling the circulation ratio R of the fine-grain elimination stream to be 2.5 for a crystallization device externally connected with a fine-grain elimination heat exchanger, controlling the temperature of the fine-grain elimination heat exchange device to be 25 ℃, controlling the crystallization temperature to be 20 ℃, controlling the retention time to be 3h, sampling after the system stabilization time is 30h, and carrying out particle size analysis, wherein the result is shown in table 3.

TABLE 3 vitamin C Crystal experiment size analysis

It can be seen from the above embodiment that, by using the crystallizer of the utility model to separate the cobalt chloride, the inorganic salts such as cobalt sulfate and the organic matters such as vitamin C by crystallization, the main particle size of the product is averagely increased by 75-180%, the coefficient of variation of particle size distribution is averagely decreased by 40-70%, and a better technical effect is obtained.

The invention has been described above by way of example, and it should be noted that any simple variants, modifications or other equivalent substitutions by a person skilled in the art without spending creative effort may fall within the scope of protection of the present invention without departing from the core of the present invention.

Claims

1. An integrated crystallizing device with continuous fine grain eliminating circulation is characterized by comprising a feed inlet, a discharge outlet, a vaporizing chamber, a fine grain eliminating circulation area and a crystal growth area, wherein a guide cylinder or a downcomer is arranged in the device, and a fine grain eliminating heat exchange device is arranged between the outer wall of the guide cylinder or the downcomer and the inner wall of the device in the fine grain eliminating circulation area.

2. The integrated crystallization device of claim 1, wherein the fine grain elimination heat exchange device is a heat exchange coil or a heat exchange plate, and is circumferentially distributed between the outer wall of the draft tube or the downcomer and the inner wall of the device in two or more circles, and the circles of heat exchange devices are spaced at intervals to form a fine grain elimination circulation channel.

3. The integrated crystallization device according to claim 1 or 2, wherein the crystallization device is further provided with a stirrer, the stirrer is a paddle type stirrer, and the paddle extends into the lower end of the inner part of the guide cylinder or the downcomer.

4. The integrated crystallization device as claimed in claim 3, wherein the crystallization device crystal growth zone is tapered and the crystallization device bottom is W-shaped.

5. The integrated crystallization device of claim 4, wherein the feed inlet is positioned at the upper part of the crystallization device and extends to the axis of the guide cylinder or the downcomer to feed downwards, and the discharge outlet is positioned at the bottom of the crystallization device.

6. The integrated crystallization device as claimed in claim 5, wherein the top of the crystallization device is provided with a steam outlet, the steam outlet is connected with an inlet of a steam compressor, an outlet of the steam compressor is connected with an inlet of a gas side of a condenser, an outlet of the gas side of the condenser is connected with an inlet of a condensate tank, and an outlet of the condensate tank is connected with a vacuum pump for discharging non-condensable gas.

7. The integrated crystallization device according to claim 6, wherein the vapor compressor is a roots compressor, a centrifugal compressor or a screw compressor.