CN111514607A - Flow guide type freezing crystallizer - Google Patents
Flow guide type freezing crystallizer Download PDFInfo
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- CN111514607A CN111514607A CN202010465549.3A CN202010465549A CN111514607A CN 111514607 A CN111514607 A CN 111514607A CN 202010465549 A CN202010465549 A CN 202010465549A CN 111514607 A CN111514607 A CN 111514607A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D9/00—Crystallisation
- B01D9/0004—Crystallisation cooling by heat exchange
- B01D9/0013—Crystallisation cooling by heat exchange by indirect heat exchange
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D9/00—Crystallisation
- B01D9/005—Selection of auxiliary, e.g. for control of crystallisation nuclei, of crystal growth, of adherence to walls; Arrangements for introduction thereof
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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- B01D9/00—Crystallisation
- B01D9/0063—Control or regulation
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Abstract
A diversion type freezing crystallizer comprises a crystallization tank, a cooling system, a stirring system and a control system; the crystallization tank comprises a tank body; the inner wall of the groove body is provided with a cold insulation layer; the tank body is provided with a manhole, a feed inlet, a liquid level meter port, a clear liquid port, a crystal slurry port and a thermometer port; the cooling system comprises an inlet main pipe, a despin coil pipe, a flow guide coil pipe, an outlet main pipe and a bracket; the stirring system comprises a variable frequency motor, a speed reducer, a water seal, a rigid shaft, a propelling paddle blade and a bottom cone; the control system comprises a liquid level sensor, a feeding switch valve, a temperature sensor, a refrigerant regulating valve, an ammeter, a variable frequency controller, a clear liquid switch valve, a crystal slurry switch valve and a logic controller; compared with the conventional intermittent groove type freezing crystallizer, the crystallizer provided by the invention has the advantages of large heat exchange area, large capacity, less scab and the like, also has a certain crystal selection function and a crystal slurry thickening function, and is beneficial to subsequent crystal slurry solid-liquid separation operation.
Description
Technical Field
The invention relates to a crystallizer, in particular to a diversion type freezing crystallizer.
Background
In the sulfuric acid process metallurgy, such as the spodumene sulfuric acid process for producing lithium carbonate and lithium hydroxide monohydrate, a large amount of sodium sulfate is produced due to the use of sulfuric acid and soda ash or liquid caustic soda. The sodium sulfate can be efficiently removed from the product solution with low consumption, which often affects the productivity and the cost. The sodium sulfate is removed by two methods, namely evaporative crystallization and freezing crystallization.
In the production process of lithium hydroxide, a freezing crystallization method is often adopted, and higher primary crystallization rate of sodium sulfate can be obtained. During the freezing process, the sodium sulfate is separated out in the form of sodium sulfate heptahydrate or sodium sulfate decahydrate according to different conditions. More common is the sodium sulfate decahydrate form, i.e., mirabilite. Mirabilite has the characteristic of narrow metastable zone width under the condition of freezing crystallization, and is easy to rapidly crystallize on the heat exchange wall surface to form crystal scars, so that the heat exchange thermal resistance is sharply increased, and the productivity is sharply reduced. The traditional process is an intermittent cooling crystallization method, and the novel process is a continuous cooling crystallization method.
The traditional intermittent cooling crystallization method has the defects of small heat exchange area of a jacket or a coil pipe and small single kettle capacity due to volume limitation, and is not beneficial to large-scale production. But its advantage is also obvious, when feeding every time, because the new material temperature is higher, the concentration is low, can dissolve the little scab of last operation fast, need not waste time and clear the scab specially. Although the technology is a traditional technology, the technology is not eliminated due to the automatic scar removing capability, and the technology is continuously used on some new projects, so that the advantages of the technology cannot be ignored.
The novel continuous cooling crystallization method introduces the structural patterns of OSLO, DTB and the like, has the functions of grain classification, clear liquid circulation, thick crystal slurry and the like, and is favorable for grain growth and separation. And meanwhile, an external heat exchanger and an external circulating pump are adopted, the heat exchange area is not limited, and the capacity of a single device can be greatly increased. But the defect is that the scabbing problem of the heat exchange tube can not be solved all the time, and the heat exchanger needs to be cleaned frequently in a production stop. The current improvement direction focuses on the two aspects of delaying the scab and quickly cleaning the scab, and has certain effect, but still is not satisfactory. Although the novel process is adopted, the process has no absolute technical advantages over the traditional process, so that the traditional process is not eliminated.
Disclosure of Invention
The invention aims to provide a flow guide type freezing crystallizer which is simple in structure, reasonable in design and convenient to use, aiming at the defects and shortcomings of the prior art.
In order to achieve the purpose, the invention adopts the technical scheme that: the device comprises a crystallization tank, a cooling system, a stirring system and a control system;
the crystallization tank comprises a tank body, a bottom bracket and a top bracket; the inner wall of the groove body is provided with a cold insulation layer; the tank body is fixed on the bottom bracket; the top bracket is fixed on the upper part of the tank body; the top of the tank body is provided with a manhole, a feed inlet and a liquid level meter port; the middle part of the side wall of the tank body is provided with a clear liquid port; the bottom of the tank body is provided with a crystal slurry port and a thermometer port;
the cooling system comprises an inlet main pipe, a despin coil pipe, a flow guide coil pipe, an outlet main pipe and a bracket; the inlet main pipe adopts a large-caliber circular ring pipe structure, and the outlet main pipe and the inlet main pipe are arranged at the same height and are both arranged above the operating liquid level of the tank body; the despin coil pipe and the diversion coil pipe are both arranged on the inner side of the tank body; the despin coil pipe is formed by bending a refrigerant pipeline, a certain gap is formed between the pipelines, and crystals can easily pass through the gap; the diversion coil pipe adopts the design of parallel connection of a plurality of coils, and the number of the parallel connection is 2-12; the outer surface of the diversion coil pipe is connected into a wave shape; the bracket is arranged in a notch at the bottom of the groove body through a reinforcing plate, is fixed by utilizing the rigidity and weight of the diversion coil pipe, supports the inlet main pipe, the outlet main pipe and the despin coil pipe, and is provided with a certain gap with the inner wall of the groove body;
the stirring system comprises a variable frequency motor, a speed reducer, a water seal, a rigid shaft, a propelling paddle blade and a bottom cone; the variable frequency motor is in control connection with the speed reducer; an output shaft of the speed reducer is connected with the upper end of the rigid shaft; the lower end of the rigid shaft penetrates through the top bracket and extends into the groove body; a plurality of propelling blades are fixed on the rigid shaft; the bottom propeller height of the propelling propeller is consistent with the bottom height of the flow guide coil pipe; the bottom cone is arranged in the middle of the bottom of the groove body;
the control system comprises a liquid level sensor, a feeding switch valve, a temperature sensor, a refrigerant regulating valve, an ammeter, a variable frequency controller, a clear liquid switch valve, a crystal slurry switch valve and a logic controller; the liquid level sensor is arranged at the liquid level meter port; the feeding switch valve is arranged at the feeding port; the temperature sensor is arranged at the thermometer port; the refrigerant regulating valve is arranged on the inlet main pipe; the ammeter and the variable frequency controller are arranged at the variable frequency motor and are electrically connected with the variable frequency motor; the clear liquid switch valve is arranged at the clear liquid port; the crystal slurry switch valve is arranged at the crystal slurry opening; the logic controller is in control connection with the feeding switch valve, the refrigerant regulating valve, the variable frequency controller, the clear liquid switch valve and the crystal slurry switch valve; the feeding switch valve KV1 is interlocked with the liquid level sensor; the refrigerant regulating valve TV is interlocked with the temperature sensor.
Furthermore, the tank body is also provided with a clean discharge port, a vent port, a cleaning port and a standby port;
furthermore, the groove body adopts a cylindrical structure, and the length-diameter ratio of the groove body is 2:1 to 1: 1;
furthermore, the cold insulation layer is manufactured by adopting an integral foaming spraying process;
furthermore, the gap between two adjacent coil pipes on the diversion coil pipe is small, and the coil pipes are tightly attached to each other through the tightening and fixing of the buckles to form a closed diversion cylinder; the diameter of the guide cylinder is 0.71 times of the inner diameter of the groove body, so that the sectional areas of the circular flow passages inside and outside the guide cylinder are equal to that of the circular flow passages; the distance between the bottom of the guide cylinder coil and the bottom of the groove body and the distance between the top of the guide cylinder and the liquid level are 1/4 times, namely 0.25 times, of the diameter of the guide cylinder;
further, the bottom cone adopts a conical structure, and the bottom radius and the height of the bottom cone are 1/2 of the height of the bottom paddle.
Furthermore, the liquid level sensor adopts a top-inserted radar liquid level meter, and the insertion point of the liquid level sensor is close to the rigid shaft of the stirring system.
After the structure is adopted, the flow guide type freezing crystallizer has the following advantages:
1. a single-groove intermittent crystallizer is adopted to retain the advantage of automatic scar removal;
2. in the single-groove intermittent crystallizer, a draft tube without a gap is formed by parallel coil pipes, so that the heat exchange area can be enlarged, the equipment capacity is improved, the flowing form is optimized, the heat transfer is enhanced, the scabbing rate is reduced, certain functions of grain classification, clear liquid circulation and thick crystal slurry are formed, and the subsequent separation is facilitated;
3. the racemization baffle is improved into a racemization coil pipe, so that the heat exchange area is further increased, a liquid descending main pipe is replaced, and the influence on the flow of crystal mush is reduced. The refrigerant inlet and outlet main pipe is arranged above the liquid level, so that the influence on the flow can be reduced;
4. all pipelines of the whole cooling system are integrated into a whole, are fixed through dead weight and clamping grooves, are not in hard connection with a tank body, can be integrally hoisted, and are easy to install and maintain;
5. structures such as a push type stirrer, a bottom cone and the like are introduced, so that mass transfer and heat transfer are further enhanced;
6. a cooling program is introduced into the control, and a refrigerant adjusting valve is matched with hardware, so that the cooling rate is accurately controlled, and the scabbing risk is reduced.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
FIG. 1 is a schematic structural view of the present invention;
FIG. 2 is a top view of the inside of a crystallization tank according to the present invention;
FIG. 3 is a bottom view of the inside of the crystallization tank of the present invention.
Description of reference numerals:
1. a trough body; 2. a manhole; 3. a feed inlet; 4. a clear liquid port; 5. a crystal slurry port; 6. a thermometer port; 7. a level gauge port; 8. an inlet manifold; 9. a despin coil pipe; 10. a flow guiding coil pipe; 11. an outlet manifold; 12. a support; 13. a variable frequency motor; 14. a speed reducer; 15. water sealing; 16. a rigid shaft; 17. a propeller blade; 18. a bottom cone; 19. a liquid level sensor; 20. a feed switch valve; 21. a temperature sensor; 22. a refrigerant regulating valve; 23. an ammeter; 24. a variable frequency controller; 25. a clear liquid switch valve; 26. crystal plasm switch valve.
Detailed Description
The invention will be further described with reference to the accompanying drawings.
The specific implementation mode is as follows: referring to the drawings of FIGS. 1-3, the device comprises a crystallization tank, a cooling system, a stirring system and a control system;
the crystallization tank comprises a tank body 1, a bottom bracket and a top bracket; the tank body 1 adopts the simplest cylindrical structure, is beneficial to arrangement and installation and arrangement of internals such as a coil pipe, a baffle plate and the like, has the length-diameter ratio of 2:1 to 1:1, and has lower manufacturing cost per unit volume. The inner wall of the tank body 1 is provided with a cold insulation layer, the cold insulation layer adopts an integral foaming spraying process, the adhesive force is strong, no gap exists, and the cold insulation effect is good; the tank body 1 is fixed on the bottom bracket; the top bracket is fixed on the upper part of the tank body 1 and is used for supporting components such as a variable frequency motor 13, a speed reducer 14 and the like; the top of the tank body 1 is provided with a manhole 2, a feed inlet 3 and a liquid level meter port 7; the middle part of the side wall of the tank body 1 is provided with a clear liquid port 4; the bottom of the tank body 1 is provided with a crystal slurry port 5 and a thermometer port 6; the tank body 1 is also provided with a clean discharge port, a drain port, a cleaning port and a standby port (not shown in the figure).
The cooling system comprises an inlet main pipe 8, a despin coil pipe 9, a flow guide coil pipe 10, an outlet main pipe 11 and a support 12; the inlet main pipe 8 adopts a large-caliber circular ring pipe structure, the flow resistance in the pipe is small, the pipe is arranged above the operating liquid level, the outlet main pipe 11 and the inlet main pipe 8 are arranged at the same height, the inlet main pipe does not contact with materials in the groove, and the flow resistance of the materials is not increased. The despin coil pipe 9 and the diversion coil pipe 10 are both arranged on the inner side of the tank body 1. The despin coil pipe 9 is formed by bending a refrigerant pipeline, so that the heat exchange area is increased, the refrigerant is sent to the bottom of the tank, the design of a common liquid descending straight pipe is replaced, and unnecessary components are reduced. Certain gaps are formed among the tubes of the despin coil pipe 9, crystals can easily pass through the gaps and are not easy to adhere and agglomerate, and the phenomenon that the discharge port is blocked due to the fact that the adhesion agglomerates easily occur in the design of a common despin plate and fall off is avoided. The flow guide coil 10 adopts a multi-coil parallel design, the parallel number is 2-12, the flow velocity in the refrigerant pipe is controlled within a reasonable range while large heat exchange area and large refrigerant flow are obtained, and the refrigerant circulation power consumption is prevented from being overlarge. During manufacturing, only a small gap is reserved in the flow guide coil 10 for welding, and then the flow guide coil is fastened and fixed through a buckle, so that the coil and the coil are tightly attached to form a closed flow guide cylinder, the flow guide cylinder has the function of guiding the flow direction of crystal slurry, the flow guide is beneficial to reducing backflow, the effective circulation flux is increased, and the circulation flow rate is improved; the outer surface of the flow guide coil pipe is connected into a wavy shape, and compared with a flat plate, the wavy surface is easy to generate turbulence, so that the thermal resistance is favorably reduced, the total energy transfer coefficient is favorably increased, the temperature difference of a heat transfer interface is favorably reduced, the scabbing speed is reduced, and the integral capacity of equipment is improved. The diameter of a guide cylinder formed by the guide coil pipe 10 is 0.71 times of the inner diameter of the tank body 1, so that the sectional areas of the circular flow passages inside and outside the guide cylinder are equal, the resistance is reduced, and the flow speed is improved; the distance between the bottom of the guide cylinder coil pipe and the bottom of the tank body 1 and the distance between the top of the guide cylinder and the liquid level are 1/4 times, namely 0.25 times, of the diameter of the guide cylinder, so that the cross sections of the cylindrical surface-shaped flow channels above and below the guide cylinder are equal to the cross sections of the flow channels in the cylinder and the cylinder, the resistance is reduced, the flow speed is improved, and the height of the device is fully utilized. As can be seen from fig. 3, the inner and outer flow passages of the guiding coiled pipe 10 are unobstructed and have no redundant parts. The support 12 falls into the notch of the tank bottom of the tank body 1 through the reinforcing plate, is fixed by utilizing the rigidity and the weight of the diversion coil pipe 10, supports the inlet main pipe 8, the outlet main pipe 11 and the despin coil pipe 9, keeps a certain gap with the inner wall of the tank body 1, and can be integrally hoisted and easily installed and maintained compared with a support supported by a common tank wall.
The stirring system comprises a variable frequency motor 13, a speed reducer 14, a water seal 15, a rigid shaft 16, a propelling paddle blade 17 and a bottom cone 18; the water seal 15 adopts self-liquid sealing, has no abrasion and no air leakage, and is particularly suitable for alkaline materials; the variable frequency motor 13 is in control connection with a speed reducer 14; an output shaft of the speed reducer 14 is connected with the upper end of the rigid shaft 16; the lower end of the rigid shaft 16 penetrates through the top bracket and extends into the tank body 1; the rigid shaft 16 has high strength and strong bending resistance, and is not easy to deform when running at a low liquid level or even idling; a plurality of propelling blades 17 are fixed on the rigid shaft 16; the propulsion type propeller blades 17 convert most of energy input by the motor into effective radial circulation, and only a few of the energy are ineffective circumferential circulation; the height of the bottom paddle is consistent with that of the bottom of the diversion coil pipe 10, so that ineffective circulation is reduced; the bottom cone 18 is arranged in the middle of the bottom of the tank body 1; the bottom cone 18 is a cone which is easy to manufacture, the bottom radius and the height of the cone are 1/2 of the bottom paddle height, and the circulation current is prevented from being interfered while the stockpiling is reduced.
The control system comprises a liquid level sensor 19, a feeding switch valve KV 120, a temperature sensor 21, a refrigerant regulating valve TV 22, a refrigerant outlet valve, an ammeter 23, a variable frequency controller 24, a clear liquid switch valve KV 225, a crystal slurry switch valve KV 326 and a logic controller (not shown in the figure); the liquid level sensor 19 is arranged at the position of the liquid level meter port 7, the liquid level sensor 19 adopts a top-inserted radar liquid level meter, the problem that a common pressure sensor is scarred and blocked is avoided, and the insertion point of the liquid level sensor is close to a stirring shaft (namely a rigid shaft 16) of a stirring system, so that error signals generated by the reflection of radar waves by a coil pipe can be effectively avoided; the feeding switch valve KV 120 is arranged at the feeding hole 3; the temperature sensor 21 is arranged at the thermometer port 6; the refrigerant regulating valve TV 22 is arranged on the inlet main pipe 8; the refrigerant outlet valve is arranged on the outlet header pipe 11; the ammeter 23 and the variable frequency controller 24 are both arranged at the variable frequency motor 13 and are electrically connected with the variable frequency motor 13; the clear liquid switch valve KV 225 is arranged at the clear liquid port 4; the crystal slurry switch valve KV 326 is arranged at the crystal slurry port 5; the logic controller is in control connection with a feeding switch valve KV 120, a refrigerant regulating valve TV 22, a variable frequency controller 24, a clear liquid switch valve KV 225 and a crystal slurry switch valve KV 326; the feeding switch valve KV 120 is interlocked with the liquid level sensor 19, when the liquid level reaches the design value during feeding, the feeding switch is immediately closed to close the KV 120, so that overflowing of the tank is prevented; the refrigerant regulating valve TV 22 is interlocked with the temperature sensor 21, and the refrigerant inlet quantity is controlled by temperature sections, so that the material temperature reduction speed is controlled, and rapid scabbing caused by too rapid temperature reduction is prevented.
The process of the diversion type freezing crystallizer in the specific embodiment is as follows:
firstly, a feeding process:
1. opening a feeding switch valve KV 120, closing other valves, injecting a solution containing sodium sulfate into a crystallizer through a pump, and precooling the solution to t = 30-40 ℃ before the solution enters the crystallizer;
2. detecting the feeding liquid level in the crystallizer by using a liquid level sensor LIC 19, closing a feeding switch valve KV 120 when the designed liquid level is reached, and finishing feeding;
3. and during the material setting period, the redundant gas in the crystallizer is automatically discharged through a vent and a breather valve.
Secondly, a crystallization process:
1. the variable frequency motor 13 is started, the frequency of the variable frequency controller 24 is set to be 50Hz, and then the frequency can be properly reduced by adjusting according to experience;
2. opening a refrigerant regulating valve TV 22 and a refrigerant outlet valve, and injecting a refrigerant into the coil pipe through a pump; the refrigerant passes through in proper order: the refrigerant regulating valve TV 22, the inlet main pipe 8, the despinning coil pipe 9, the diversion coil pipe 10, the outlet main pipe 11 and the refrigerant outlet valve exchange heat with the material in the crystallization tank through the despinning coil pipe 9 and the diversion coil pipe 10, so that the temperature of the material liquid is reduced;
3. the opening degree of the refrigerant regulating valve TV 22 is controlled by a logic controller in a programming mode, the material temperature is reduced according to the program, different cooling rates exist in different temperature sections, and the specific cooling rate is shown in the following table:
| temperature section | 40-25℃ | 25-5℃ | 10-0℃ | 0-－5℃ |
| Rate of |
15±3℃/h | 5±1℃/h | 4±0.8℃/h | 3±0.6℃/h |
| When in use | -1h | -4h | -2.5h | -1.7h |
Since the cooling rate is not completely as expected, the crystallization process takes a certain time, generally 8.2-12.3h, and typically 9.2 h.
Thirdly, growing the crystal:
the frequency of the variable frequency controller 24 is set at 15-25Hz, and then is adjusted according to experience and can be reduced appropriately;
2. the tank temperature is set to-5 +/-1 ℃, the flow of the refrigerant is adjusted through a refrigerant adjusting valve TV 22, and the micro heat transferred from the surface of the equipment and generated by internal friction is taken away;
3. the crystal growth time is 0.5-1h for growing the crystal grains. When the feeding components are changed, the crystal growing time needs to be adjusted.
Fourthly, a sedimentation process:
1. setting the frequency of the variable frequency controller 24 to 0Hz, and then closing the variable frequency motor 13;
2. the settling time is 0.5-1h, so that the crystal grains settle to the bottom of the tank, and the settling time needs to be adjusted when the feed components change;
3. and opening a clear liquid switch valve 25, sampling and observing whether the discharged feed liquid is clear, if so, continuing to settle for 0.5-1h, and if not, ending the settling.
Fifthly, discharging:
1. opening the clear liquid switch valve 22 to discharge the clear solution at the upper half part;
2. after the supernatant is discharged, starting a variable frequency motor 13, and setting the frequency to be 5-10 Hz;
3. after 10min, opening a crystal slurry switch valve 26, and discharging the lower half part of crystal slurry;
4. after the crystal mush is discharged, the frequency of the variable frequency controller 24 is set to 0Hz, and then the variable frequency motor 13 is closed.
Example 1: the feed liquid of the sodium sulfate solution comprises the following components: LiOH 4.2%, NaOH 1.1%, Na2SO431.0 percent and the feeding temperature is 39 ℃;
in the crystallization process, the time spent at 40-25 ℃ is 90min, the time spent at 25-5 ℃ is 242min, the time spent at 10-0 ℃ is 146min, the time spent at 0-5 ℃ is 110min, and the total time is 588min, namely 9.8 h;
the time for the crystal growing process is 1 h;
in the sedimentation process, after 30min, sampling from the clear liquid port 4, a small amount of solid still exists, after 30min of secondary sedimentation, sampling from the clear liquid port 4, and no obvious solid exists, wherein the sedimentation process is shared for 1 h;
in the discharging process, the time for discharging clear liquid is 58min, the time for discharging crystal mush is 74min, and the total time is 132min, namely 2.2 h;
the total time of the whole process is 14.0h, and the clear liquid comprises the following components: 9.5 percent of LiOH, 2.5 percent of NaOH and Na2SO44.0%。Na2SO4∙10H2The O crystallization rate is 94.3 percent.
Example 2: the feed liquid of the sodium sulfate solution comprises the following components: LiOH 4.4%, NaOH 1.2%, Na2SO430.5 percent. The feed temperature was 37 ℃.
In the crystallization process, the time spent at 40-25 ℃ is 86min, the time spent at 25-5 ℃ is 236min, the time spent at 10-0 ℃ is 148min, the time spent at 0-5 ℃ is 115min, and the total time is 585min, namely 9.8 h;
the time for the crystal growing process is 1 h;
in the sedimentation process, sampling is carried out from a clear liquid port 4 after 30min, no obvious solid exists, and the sedimentation process is shared for 0.5 h;
in the discharging process, the time for discharging clear liquid is 55min, the time for discharging crystal mush is 75min, and the total time is 130min, namely 2.2 h;
the total time of the whole process is 13.4 hours, and the clear liquid comprises the following components: 9.8% of LiOH, 2.7% of NaOH and Na2SO44.2%。Na2SO4∙10H2The crystallization rate of O is 93.8 percent
The above description is only for the purpose of illustrating the technical solutions of the present invention and not for the purpose of limiting the same, and other modifications or equivalent substitutions made by those skilled in the art to the technical solutions of the present invention should be covered within the scope of the claims of the present invention without departing from the spirit and scope of the technical solutions of the present invention.
Claims (7)
1. A diversion type freezing crystallizer is characterized by comprising a crystallization tank, a cooling system, a stirring system and a control system;
the crystallization tank comprises a tank body, a bottom bracket and a top bracket; the inner wall of the groove body is provided with a cold insulation layer; the tank body is fixed on the bottom bracket; the top bracket is fixed on the upper part of the tank body; the top of the tank body is provided with a manhole, a feed inlet and a liquid level meter port; the middle part of the side wall of the tank body is provided with a clear liquid port; the bottom of the tank body is provided with a crystal slurry port and a thermometer port;
the cooling system comprises an inlet main pipe, a despin coil pipe, a flow guide coil pipe, an outlet main pipe and a bracket; the inlet main pipe adopts a large-caliber circular ring pipe structure, and the outlet main pipe and the inlet main pipe are arranged at the same height and are both arranged above the operating liquid level of the tank body; the despin coil pipe and the diversion coil pipe are both arranged on the inner side of the tank body; the despin coil pipe is formed by bending a refrigerant pipeline, a certain gap is formed between the pipelines, and crystals can easily pass through the gap; the diversion coil pipe adopts the design of parallel connection of a plurality of coils, and the number of the parallel connection is 2-12; the outer surface of the diversion coil pipe is connected into a wave shape; the bracket is arranged in a notch at the bottom of the groove body through a reinforcing plate, is fixed by utilizing the rigidity and weight of the diversion coil pipe, supports the inlet main pipe, the outlet main pipe and the despin coil pipe, and is provided with a certain gap with the inner wall of the groove body;
the stirring system comprises a variable frequency motor, a speed reducer, a water seal, a rigid shaft, a propelling paddle blade and a bottom cone; the variable frequency motor is in control connection with the speed reducer; an output shaft of the speed reducer is connected with the upper end of the rigid shaft; the lower end of the rigid shaft penetrates through the top bracket and extends into the groove body; a plurality of propelling blades are fixed on the rigid shaft; the bottom propeller height of the propelling propeller is consistent with the bottom height of the flow guide coil pipe; the bottom cone is arranged in the middle of the bottom of the groove body;
the control system comprises a liquid level sensor, a feeding switch valve, a temperature sensor, a refrigerant regulating valve, an ammeter, a variable frequency controller, a clear liquid switch valve, a crystal slurry switch valve and a logic controller; the liquid level sensor is arranged at the liquid level meter port; the feeding switch valve is arranged at the feeding port; the temperature sensor is arranged at the thermometer port; the refrigerant regulating valve is arranged on the inlet main pipe; the ammeter and the variable frequency controller are arranged at the variable frequency motor and are electrically connected with the variable frequency motor; the clear liquid switch valve is arranged at the clear liquid port; the crystal slurry switch valve is arranged at the crystal slurry opening; the logic controller is in control connection with the feeding switch valve, the refrigerant regulating valve, the variable frequency controller, the clear liquid switch valve and the crystal slurry switch valve; the feeding switch valve KV1 is interlocked with the liquid level sensor; the refrigerant regulating valve TV is interlocked with the temperature sensor.
2. The flow-guiding type freezing crystallizer of claim 1, wherein the tank body is further provided with a drain port, a cleaning port and a standby port.
3. The flow-guiding type freezing crystallizer as claimed in claim 1 or 2, wherein the tank body is of a cylindrical structure, and the length-diameter ratio of the tank body is 2:1 to 1: 1.
4. The flow-guiding type freezing crystallizer of claim 1, wherein the cold insulation layer is made by an integral foaming spraying process.
5. The flow-guiding type freezing crystallizer of claim 1, wherein the gap between two adjacent coils on the flow-guiding coil is small, and the coil are tightly attached to form a closed flow-guiding cylinder by tightening and fixing the coil by a fastener; the diameter of the guide cylinder is 0.71 times of the inner diameter of the groove body, so that the sectional areas of the circular flow passages inside and outside the guide cylinder are equal to that of the circular flow passages; the distance between the bottom of the draft tube coil and the bottom of the groove body and the distance between the top of the draft tube and the liquid level are 1/4 times, namely 0.25 times, of the diameter of the draft tube.
6. The flow-guiding type freezing crystallizer of claim 1, wherein the bottom cone is a conical structure, and the bottom radius and height of the bottom cone are 1/2 of the height of the bottom paddle.
7. A flow-guiding type freezing crystallizer as claimed in claim 1, wherein the liquid level sensor is a top-inserted radar level gauge, and its insertion point is close to the rigid shaft of the stirring system.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1992012392A1 (en) * | 1991-01-07 | 1992-07-23 | Comalco Aluminium Limited | Heating and/or cooling of vessels |
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| CN2865843Y (en) * | 2006-01-18 | 2007-02-07 | 内蒙古蒙西高新技术集团有限公司 | Polymerization reactor |
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2020
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| JPH10151301A (en) * | 1996-11-26 | 1998-06-09 | Mitsui Chem Inc | Method for separating or purifying material from mixed solution by crystallization |
| CN2514887Y (en) * | 2001-11-27 | 2002-10-09 | 核工业北京化工冶金研究院 | Multifunctional setting crystallization tank |
| CN2865843Y (en) * | 2006-01-18 | 2007-02-07 | 内蒙古蒙西高新技术集团有限公司 | Polymerization reactor |
| CN205832670U (en) * | 2016-07-16 | 2016-12-28 | 台州世控自动化设备有限公司 | Crystallization kettle temperature control system |
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