CN221275311U - Gradient freezing crystallization device for disodium hydrogen phosphate wastewater - Google Patents
Gradient freezing crystallization device for disodium hydrogen phosphate wastewater Download PDFInfo
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- CN221275311U CN221275311U CN202323081495.9U CN202323081495U CN221275311U CN 221275311 U CN221275311 U CN 221275311U CN 202323081495 U CN202323081495 U CN 202323081495U CN 221275311 U CN221275311 U CN 221275311U
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- 238000007710 freezing Methods 0.000 title claims abstract description 131
- 230000008014 freezing Effects 0.000 title claims abstract description 131
- BNIILDVGGAEEIG-UHFFFAOYSA-L disodium hydrogen phosphate Chemical compound [Na+].[Na+].OP([O-])([O-])=O BNIILDVGGAEEIG-UHFFFAOYSA-L 0.000 title claims abstract description 61
- 239000002351 wastewater Substances 0.000 title claims abstract description 28
- 238000002425 crystallisation Methods 0.000 title claims abstract description 21
- 230000008025 crystallization Effects 0.000 title claims abstract description 20
- 239000007788 liquid Substances 0.000 claims abstract description 45
- 239000013078 crystal Substances 0.000 claims abstract description 37
- 238000005057 refrigeration Methods 0.000 claims abstract description 35
- 238000007599 discharging Methods 0.000 claims abstract description 30
- 239000002002 slurry Substances 0.000 claims abstract description 21
- 239000000463 material Substances 0.000 claims abstract description 20
- 230000001174 ascending effect Effects 0.000 claims abstract description 8
- 239000012452 mother liquor Substances 0.000 claims description 37
- 239000003507 refrigerant Substances 0.000 claims description 17
- 238000000926 separation method Methods 0.000 claims description 7
- 238000004064 recycling Methods 0.000 claims description 6
- 239000007791 liquid phase Substances 0.000 claims description 4
- 239000007790 solid phase Substances 0.000 claims description 4
- 238000005265 energy consumption Methods 0.000 abstract description 4
- 238000011144 upstream manufacturing Methods 0.000 abstract 1
- 238000000034 method Methods 0.000 description 18
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical class OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 10
- 230000008569 process Effects 0.000 description 10
- 230000006872 improvement Effects 0.000 description 8
- 239000003795 chemical substances by application Substances 0.000 description 6
- 238000001816 cooling Methods 0.000 description 6
- 239000002245 particle Substances 0.000 description 6
- 230000009471 action Effects 0.000 description 5
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 5
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 3
- 230000008901 benefit Effects 0.000 description 3
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 230000005484 gravity Effects 0.000 description 3
- 150000003839 salts Chemical class 0.000 description 3
- 239000007787 solid Substances 0.000 description 3
- 239000004129 EU approved improving agent Substances 0.000 description 2
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000009776 industrial production Methods 0.000 description 2
- 230000014759 maintenance of location Effects 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 238000004062 sedimentation Methods 0.000 description 2
- 239000010865 sewage Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000003115 biocidal effect Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 239000013064 chemical raw material Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 239000003599 detergent Substances 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 238000004043 dyeing Methods 0.000 description 1
- 238000005868 electrolysis reaction Methods 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 239000013072 incoming material Substances 0.000 description 1
- 239000008235 industrial water Substances 0.000 description 1
- 238000005342 ion exchange Methods 0.000 description 1
- 239000004973 liquid crystal related substance Substances 0.000 description 1
- 229910000403 monosodium phosphate Inorganic materials 0.000 description 1
- 235000019799 monosodium phosphate Nutrition 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 230000003472 neutralizing effect Effects 0.000 description 1
- 239000012071 phase Substances 0.000 description 1
- 235000021317 phosphate Nutrition 0.000 description 1
- 150000003013 phosphoric acid derivatives Chemical class 0.000 description 1
- 239000000049 pigment Substances 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 239000013049 sediment Substances 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 229910000029 sodium carbonate Inorganic materials 0.000 description 1
- AJPJDKMHJJGVTQ-UHFFFAOYSA-M sodium dihydrogen phosphate Chemical compound [Na+].OP(O)([O-])=O AJPJDKMHJJGVTQ-UHFFFAOYSA-M 0.000 description 1
- 239000001488 sodium phosphate Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Abstract
The utility model discloses a gradient freezing crystallization device for disodium hydrogen phosphate wastewater, which comprises: 1. the liquid outlets of the second-stage freezing crystallizer and the third-stage freezing crystallizer are connected with the inlets of the forced circulation pumps through the circulation pipes; 1. the tube side inlets of the second-stage refrigeration heat exchanger and the third-stage refrigeration heat exchanger are connected with the outlets of the corresponding forced circulation pumps, and the tube side outlets are connected with the top inlets of the corresponding refrigeration crystallizers; the primary freezing feed pipe is connected with the tube side ascending pipe of the primary freezing heat exchanger, and the cone wall outlet of the primary freezing crystallizer is connected with the tube side ascending pipe of the secondary freezing heat exchanger through the primary material transferring pump and the primary material discharging pipe; the cone wall outlet of the secondary freezing crystallizer is connected with the feed inlet of the tertiary freezing crystallizer through a secondary material transferring pump and a secondary material discharging pipe; the cone wall outlet of the three-stage freezing crystallizer is connected with a crystal slurry discharging pipe. And a precooling unit is arranged at the upstream of the primary freezing crystallizer. The crystal obtained by the device has large granularity, good running continuity and stability and low comprehensive energy consumption.
Description
Technical Field
The utility model relates to a freezing crystallization device, in particular to a gradient freezing crystallization device for disodium hydrogen phosphate wastewater, and belongs to the technical field of resource recycling.
Background
Disodium hydrogen phosphate, also known as monosodium phosphate, is one of the sodium acid salts of phosphoric acid. It is a deliquescent white powder, soluble in water, and weakly alkaline in aqueous solution. Disodium hydrogen phosphate is a widely used chemical raw material, and can be used for preparing citric acid, water softener, fabric weighting agent and fireproof agent, and can be used for preparing glaze, welding flux, medicine, pigment, food industry and other phosphates as industrial water quality treating agents, printing and dyeing detergents, quality improving agents, neutralizing agents, antibiotic culture agents, biochemical treating agents, food quality improving agents and the like.
The disodium hydrogen phosphate is influenced by factors such as production places, grades, prices and the like of raw materials, production processes adopted by different manufacturers are different, the purity of products is also greatly different, the production method of the disodium hydrogen phosphate mainly comprises a neutralization method, an extraction method, an ion exchange method, a double decomposition method, a direct method, a crystallization method, an electrolysis method and the like, and the preparation of the disodium hydrogen phosphate with higher purity mainly adopts a direct method. The current industrial production of disodium hydrogen phosphate is basically prepared by reacting phosphoric acid by a hot method or purified phosphoric acid by a wet method with potassium hydroxide or sodium carbonate because the wet phosphoric acid process is still immature, so that the production method is limited.
In the industrial production process, a large amount of disodium hydrogen phosphate wastewater is generated, and the disodium hydrogen phosphate wastewater is directly discharged to pollute the environment seriously, so that the disodium hydrogen phosphate wastewater needs to be treated. The disodium hydrogen phosphate wastewater generally contains more solid particles, and when the direct-current sedimentation tank is used for treatment, the sedimentation treatment effect can be achieved on the solid particles, but the treatment efficiency is low, and the sediment is more troublesome to clean. And then, disodium hydrogen phosphate wastewater is treated by adopting a freezing crystallization mode, so that the required heat exchange area is large, the occupied area is large, the pipe is easy to block, and the required refrigerant amount is large. Therefore, a reasonable scheme for treating the disodium hydrogen phosphate wastewater is designed in an optimized way under the condition of comprehensively considering the overall economic benefit of freezing crystallization.
The Chinese patent application with publication number of CN112479172A discloses a production method of disodium hydrogen phosphate, in particular to a method for preparing industrial grade disodium hydrogen phosphate by utilizing byproduct etching and waste phosphoric acid for cleaning of liquid crystal panels and semiconductor wafer enterprises to recycle, and adopts a cooling and freezing crystallization process to prepare disodium hydrogen phosphate. There are the following problems: 1. the cooling process adopts direct cooling, so that the supersaturation degree cannot be effectively eliminated; 2. the freezing process has no energy recovery and large cold energy consumption; 3. the quality of the crystalline salt is poor.
Disclosure of utility model
This section is intended to outline some aspects of embodiments of the utility model and to briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section as well as in the description of the utility model and in the title of the utility model, which may not be used to limit the scope of the utility model.
The present utility model has been made in view of the above and/or problems occurring in the prior art.
The utility model aims to overcome the problems in the prior art and provide a gradient freezing crystallization device for disodium hydrogen phosphate wastewater, which has the advantages of large crystal granularity, good quality, good continuity and stability of device operation and low comprehensive energy consumption.
In order to solve the technical problems, the gradient freezing crystallization device for disodium hydrogen phosphate wastewater provided by the utility model comprises:
the liquid outlet of the primary freezing crystallizer is connected with the inlet of the primary forced circulation pump through the primary circulation pipe;
The lower inlet of the tube side of the primary freezing heat exchanger is connected with the outlet of the primary forced circulation pump, and the upper outlet of the tube side is connected with the top inlet of the primary freezing crystallizer;
the liquid outlet of the secondary freezing crystallizer is connected with the inlet of the secondary forced circulation pump through a secondary circulation pipe;
the lower inlet of the tube side of the secondary freezing heat exchanger is connected with the outlet of the secondary forced circulation pump, and the upper outlet of the tube side is connected with the top inlet of the secondary freezing crystallizer;
The liquid outlet of the three-stage freezing crystallizer is connected with the inlet of the three-stage forced circulation pump through a three-stage circulation pipe;
The lower inlet of the tube pass of the three-stage freezing heat exchanger is connected with the outlet of the three-stage forced circulation pump, and the upper outlet of the tube pass is connected with the top inlet of the three-stage freezing crystallizer;
The primary freezing heat exchanger comprises a primary freezing heat exchanger, a primary freezing feed pipe, a primary material transferring pump, a primary discharging pipe, a primary freezing crystallizer, a secondary freezing heat exchanger and a secondary freezing heat exchanger, wherein a tube side outlet ascending pipe of the primary freezing heat exchanger is connected with the primary freezing feed pipe, a cone wall outlet of the primary freezing crystallizer is connected with the primary discharging pipe through the primary material transferring pump, and an outlet of the primary discharging pipe is connected with a tube side outlet ascending pipe of the secondary freezing heat exchanger; the cone wall outlet of the secondary freezing crystallizer is connected with a secondary discharging pipe through a secondary material transferring pump, and the outlet of the secondary discharging pipe is connected with the feeding inlet of the tertiary freezing crystallizer; and the cone wall outlet of the three-stage freezing crystallizer is connected with a crystal slurry discharging pipe.
As an improvement of the utility model, the outlet of the crystal slurry discharging pipe is connected with the inlet of a centrifugal machine, and the solid phase outlet of the centrifugal machine is connected with the inlet of a screw conveyor; and a liquid phase outlet of the centrifugal machine is connected with an inlet of the centrifugal mother liquid tank through a gas-liquid separation pipe.
As a further improvement of the utility model, two groups of three-stage refrigeration heat exchangers, three-stage circulating pipes and three-stage forced circulating pumps are symmetrically arranged on two sides of the three-stage refrigeration crystallizer, shell side inlets of the three-stage refrigeration heat exchangers are respectively connected with a refrigerant feeding pipe, and shell side outlets of the three-stage refrigeration heat exchangers are respectively connected with a refrigerant discharging pipe.
As a further improvement of the utility model, the outlet of the centrifugal mother liquor tank is connected with the inlet of the mother liquor discharge pump, the outlet of the mother liquor discharge pump is connected with the shell side inlet of the secondary refrigeration heat exchanger through a mother liquor recycling pipe, and the shell side outlet of the secondary refrigeration heat exchanger is connected with the shell side inlet of the primary refrigeration heat exchanger.
As a further improvement of the utility model, the outlet of the disodium hydrogen phosphate wastewater feed pipe is connected with the hot side inlet of the plate-type precooler, the hot side outlet of the plate-type precooler is connected with the hot side inlet of the tube-in-tube precooler, and the hot side outlet of the tube-in-tube precooler is connected with the first-stage freezing feed pipe.
As a further improvement of the utility model, the tube-in-tube precooler comprises a first tube-in-tube precooler and a second tube-in-tube precooler, wherein the hot side outlet of the plate-type precooler is connected with the hot side inlet of the first tube-in-tube precooler, the hot side outlet of the first tube-in-tube precooler is connected with the hot side inlet of the second tube-in-tube precooler, and the hot side outlet of the second tube-in-tube precooler is connected with the first-stage cryofeed pipe.
As a further improvement of the utility model, the plate precooler comprises a first plate precooler and a second plate precooler, wherein the outlet of the disodium hydrogen phosphate wastewater feed pipe is connected with the hot side inlet of the first plate precooler, the hot side outlet of the first plate precooler is connected with the hot side inlet of the second plate precooler, and the hot side outlet of the second plate precooler is connected with the hot side inlet of the first tube array precooler.
As a further improvement of the utility model, the shell side outlet of the primary refrigeration heat exchanger is connected with the cold side inlet of the second column tube precooler, the cold side outlet of the second column tube precooler is connected with the cold side inlet of the first column tube precooler, the cold side outlet of the first column tube precooler is connected with the cold side inlet of the second plate-type precooler, and the cold side outlet of the second plate-type precooler is connected with the cold side inlet of the first plate-type precooler.
Compared with the prior art, the utility model has the following beneficial effects: 1. the mode that the plate-type precooler is connected with the column Guan Yuleng in series is adopted, so that the tube blockage is avoided in the precooling process of disodium hydrogen phosphate;
2. the plurality of refrigerators are connected in series, so that the overlarge occupied area of the device is avoided; the gradient cooling mode is adopted to prevent fine crystals generated by rapid cooling, and each freezing unit is provided with a control valve to reduce the loss of disodium hydrogen phosphate;
3. The disodium hydrogen phosphate centrifugal mother liquor is respectively subjected to heat exchange with a plate-type precooler, a column Guan Yuleng device and a secondary refrigeration heat exchanger, and the mother liquor is utilized in multiple stages, so that the use of a refrigerant medium is greatly reduced, and the energy consumption of a system is reduced;
4. The system adopts a self-circulation forced refrigeration system, so that the growth speed of disodium hydrogen phosphate is improved, the pipe blockage phenomenon in the refrigeration process is reduced, and the stability of the refrigeration system is improved; the forced circulation pump pushes the feed liquid in the freezing crystallizer to return to the freezing crystallizer from the feed liquid circulation pipe to form a feed liquid forced circulation process, so that the blocking phenomenon of the feed liquid is reduced, the purpose of continuous operation can be achieved, the retention time of the feed liquid is prolonged, and a powerful condition is provided for the growth of crystals;
5. The freezing crystallizer adopts an OSLO crystallizer, the bottom of the crystal growing chamber is arc-shaped, the flowing state of crystal slurry in the crystal growing device is effectively improved, the forming and retention time of the crystal slurry are improved, the crystallization granularity is improved, and the problem of the equivalent rate of a subsequent centrifugal machine is solved. The mother liquor discharge pipe is arranged at the upper cone part of the crystal growing device, so that the liquid level in the mother liquor control tank can be controlled, fine crystals can be discharged, crystal nucleus in the tank is kept relatively stable, and salt grain growth is facilitated;
6. The disodium hydrogen phosphate feed liquid cooled by the refrigerator enters the refrigerator and then enters the lower part of the refrigerator through the guide pipe at the upper part of the refrigerator, then the disodium hydrogen phosphate feed liquid rises to the liquid outlet of the refrigerator, the disodium hydrogen phosphate feed liquid in the whole process is subjected to the action of gravity, the disodium hydrogen phosphate crystals with large particle size are sunk through the gravity, the disodium hydrogen phosphate crystals with smaller particle size are extracted through the liquid outlet, and the disodium hydrogen phosphate crystals float to the liquid outlet of the refrigerator and continue to participate in circulation to prolong the residence time, so that crystal grains grow and the product quality is improved;
7. Through a large number of sensors and pneumatic regulating valves, the automation degree of the system is effectively improved, and the automatic control of the system is better realized.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings required for the description of the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present utility model, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art, the drawings being provided for reference and illustration only and not for limiting the present utility model. Wherein:
FIG. 1 is a flow chart of a gradient freezing crystallization device of disodium hydrogen phosphate wastewater;
In the figure: 1. a first plate precooler; 2. a second plate precooler; 3. a first column tube precooler; 4. a second column tube precooler; 5. a primary refrigeration heat exchanger; 6. a primary freezing crystallizer; 7. a secondary refrigeration heat exchanger; 8. a secondary freezing crystallizer; 9. a three-stage freezing crystallizer; 10. a three-stage freezing crystallizer; 11. a centrifuge; 12. a screw conveyor; 13. and centrifuging the mother liquor tank.
B1. A first-stage forced circulation pump; B2. a first-stage material transferring pump; B3. a secondary forced circulation pump; B4. a secondary transfer pump; B5. a three-stage forced circulation pump; B6. mother liquor discharge pump.
G1. Disodium hydrogen phosphate wastewater feeding pipe; G2. a first-stage circulation pipe; G3. a primary sewage pipe; G4. a primary return pipe; G5. a primary discharge pipe; G6. a primary balance pipe; G7. a secondary circulation pipe; G8. a secondary sewage discharge pipe; G9. a secondary return pipe; G10. a secondary discharge pipe; G11. a secondary balance pipe; G12. a three-stage circulation pipe; G13. an exhaust gas discharge pipe; G14. a three-stage blow-down pipe; G15. a crystal slurry discharging pipe; G16. a gas-liquid separation pipe; G17. a mother liquor recycling pipe; G18. a mother liquor return pipe; G19. a refrigerant feed pipe; G20. and a refrigerant discharging pipe.
Detailed Description
In the following description of the present utility model, the terms "upper", "lower", "front", "rear", "left", "right", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are merely for convenience in describing the present utility model and simplifying the description, and do not mean that the device must have a specific orientation.
The utility model is further described with reference to the following detailed drawings in order to make the technical means, the creation characteristics, the achievement of the purpose and the effect of the implementation of the utility model easy to understand. It will be apparent that the described embodiments are only some, but not all, embodiments of the utility model.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this utility model belongs. The terminology used herein in the description of the utility model is for the purpose of describing particular embodiments only and is not intended to be limiting of the utility model.
As shown in fig. 1, the disodium hydrogen phosphate gradient freeze crystallization device comprises a primary freeze heat exchanger 5, a primary freeze crystallizer 6, a secondary freeze heat exchanger 7, a secondary freeze crystallizer 8, a tertiary freeze heat exchanger 9, a tertiary freeze crystallizer 10, a centrifuge 11, a screw conveyor 12 and a centrifugal mother liquor tank 13, wherein the primary freeze crystallizer 6, the secondary freeze crystallizer 8 and the tertiary freeze crystallizer 10 are all OSLO crystallizers.
The precooling unit comprises a plate precooler and a column Guan Yuleng, wherein the plate precooler comprises a first plate precooler 1 and a second plate precooler 2, and the column precooler comprises a first column precooler 3 and a second column precooler 4. The outlet of the disodium hydrogen phosphate wastewater feed pipe G1 is connected with the hot side inlet of the first plate type precooler 1, the hot side outlet of the first plate type precooler 1 is connected with the hot side inlet of the second plate type precooler 2, the hot side outlet of the second plate type precooler 2 is connected with the hot side inlet of the first tube array precooler 3, the hot side outlet of the first tube array precooler 3 is connected with the hot side inlet of the second tube array precooler 4, and the hot side outlet of the second tube array precooler 4 is connected with the first-stage freezing feed pipe.
The liquid outlet of the primary freezing crystallizer 6 is connected with the inlet of the primary forced circulation pump B1 through the primary circulation pipe G2, the outlet of the primary forced circulation pump B1 is connected with the inlet at the lower part of the tube side of the primary freezing heat exchanger 5, the outlet at the upper part of the tube side of the primary freezing heat exchanger 5 is connected with the inlet at the top of the primary freezing crystallizer 6, and the outlet of the primary freezing feed pipe is connected with the ascending pipe at the outlet of the tube side of the primary freezing heat exchanger 5.
The liquid outlet of the secondary freezing crystallizer 8 is connected with the inlet of the secondary forced circulation pump B3 through a secondary circulation pipe G7, the outlet of the secondary forced circulation pump B3 is connected with the inlet at the lower part of the tube side of the secondary freezing heat exchanger 7, and the outlet at the upper part of the tube side of the secondary freezing heat exchanger 7 is connected with the inlet at the top of the secondary freezing crystallizer 8.
The liquid outlet of the three-stage freezing crystallizer 10 is connected with the inlet of a three-stage forced circulation pump B5 through a three-stage circulation pipe G12, the outlet of the three-stage forced circulation pump B5 is connected with the lower inlet of the tube side of the three-stage freezing heat exchanger 9, and the upper outlet of the tube side of the three-stage freezing heat exchanger 9 is connected with the top inlet of the three-stage freezing crystallizer 10. Two groups of three-stage refrigeration heat exchangers 9, three-stage circulating pipes G12 and three-stage forced circulating pumps B5 are symmetrically arranged on two sides of a three-stage refrigeration crystallizer 10, shell side inlets of the three-stage refrigeration heat exchangers 9 are respectively connected with a refrigerant feeding pipe G19, and shell side outlets of the three-stage refrigeration heat exchangers 9 are respectively connected with a refrigerant discharging pipe G20.
The cone wall outlet of the primary freezing crystallizer 6 is connected with a primary discharging pipe G5 through a primary material transferring pump B2, and the outlet of the primary discharging pipe G5 is connected with a tube side outlet ascending pipe of the secondary freezing heat exchanger 7; the outlet of the conical wall of the secondary freezing crystallizer 8 is connected with a secondary discharging pipe G10 through a secondary material transferring pump B4, and the outlet of the secondary discharging pipe G10 is connected with the feed inlet of the tertiary freezing crystallizer 10; the conical wall outlet of the three-stage freezing crystallizer 10 is connected with a crystal slurry discharging pipe G15.
The outlet of the crystal slurry discharging pipe G15 is connected with the inlet of the centrifugal machine 11, and the solid phase outlet of the centrifugal machine 11 is connected with the inlet of the screw conveyor 12; the liquid phase outlet of the centrifugal machine 11 is connected with the inlet of a centrifugal mother liquor tank 13 through a gas-liquid separation pipe.
The outlet of the centrifugal mother liquor tank 13 is connected with the inlet of the mother liquor discharge pump B6, the outlet of the mother liquor discharge pump B6 is connected with the shell side inlet of the secondary refrigeration heat exchanger 7 through a mother liquor recycling pipe G17, the shell side outlet of the secondary refrigeration heat exchanger 7 is connected with the shell side inlet of the primary refrigeration heat exchanger 5, the shell side outlet of the primary refrigeration heat exchanger 5 is connected with the cold side inlet of the second column tube precooler 4, the cold side outlet of the second column tube precooler 4 is connected with the cold side inlet of the first column tube precooler 3, the cold side outlet of the first column tube precooler 3 is connected with the cold side inlet of the second plate precooler 2, and the cold side outlet of the second plate precooler 2 is connected with the cold side inlet of the first plate precooler 1.
The working process of the device is as follows:
The 40 ℃ incoming material sent out by the disodium hydrogen phosphate wastewater feed pipe G1 sequentially enters a first plate precooler 1 and a second plate precooler 2 to exchange heat with low-temperature mother liquor, so that the temperature of the feed liquor is reduced to 33 ℃ in advance, and then enters a first tube-array precooler 3 and a second tube-array precooler 4 to exchange heat with the low-temperature mother liquor, so that the temperature of the feed liquor is reduced to 26 ℃ in advance.
The precooled disodium hydrogen phosphate wastewater enters an upper circulating pipe at a shell side outlet of a primary freezing heat exchanger 5, primary circulating feed liquid is mixed with a precooled new feed liquid after heat exchange and temperature reduction of the primary freezing heat exchanger 5 and mother liquid under the action of a primary forced circulating pump B1, then enters a primary freezing crystallizer 6, the temperature is reduced along with the heat exchange of the feed liquid, the saturation is increased, the material enters the bottom of the primary freezing crystallizer 6 along a pipeline, then the material rises from the bottom to pass through a crystallized bed layer, the saturation is reduced, disodium hydrogen phosphate is separated out, and then disodium hydrogen phosphate crystal slurry rises to a liquid outlet of the primary freezing crystallizer 6 to flow out, and enters a primary circulating pipe G2 and the primary forced circulating pump B1 for circulation.
The primary crystal slurry discharged from the conical wall at the lower part of the primary freezing crystallizer 6 is sent out by a primary transfer pump B2, one part of the primary crystal slurry returns to the primary circulation pipe G2 through a primary return pipe G4, the other part of the primary crystal slurry is sent into an upper circulation pipe at the outlet of the secondary freezing heat exchanger 7 through a primary discharge pipe G5, the secondary circulation material liquid is mixed with the primary transferred material liquid after heat exchange and cooling of the secondary freezing heat exchanger 7 and mother liquor under the action of the secondary forced circulation pump B3, then the primary crystal slurry enters the secondary freezing crystallizer 8, the temperature is lowered along with the heat exchange of the material liquid, the saturation degree is increased, the material enters the bottom of the secondary freezing crystallizer 8 along a pipeline, then the material rises from the bottom to pass through a crystallized bed layer, the saturation degree is reduced, the disodium hydrogen phosphate is further separated out, the disodium hydrogen phosphate enters the bottom of the secondary freezing crystallizer 8 along a central pipe, then rises to the liquid outlet of the secondary freezing crystallizer 8, and then enters the secondary G7 and the secondary forced circulation pump B3 for circulation.
In the whole process, disodium hydrogen phosphate crystal slurry enables disodium hydrogen phosphate crystals with large particle sizes to sink under the action of gravity, disodium hydrogen phosphate crystals with smaller particle sizes float up to a liquid outlet of a freezing crystallizer, and the disodium hydrogen phosphate crystals and precooled feed or upper-level feed participate in circulation.
The cone bottom of the primary freezing crystallizer 6 is connected with the primary circulating pipe G2 through a primary blow-down pipe G3, and the cone bottom of the secondary freezing crystallizer 8 is connected with the secondary circulating pipe G7 through a secondary blow-down pipe G8.
The top of the primary freezing crystallizer 6 is connected with the top of the secondary freezing crystallizer 8 through a primary balance pipe G6.
The liquid outlet of the three-stage freezing crystallizer 10 is connected with the inlet of a three-stage forced circulation pump B5 through a three-stage circulation pipe G12, the outlet of the three-stage forced circulation pump B5 is connected with the lower inlet of the tube side of the three-stage freezing heat exchanger 9, and the upper outlet of the tube side of the three-stage freezing heat exchanger 9 is connected with the upper inlet of the three-stage freezing crystallizer 10. Two groups of three-stage circulation pipes G12, three-stage forced circulation pumps B5 and three-stage freezing heat exchangers 9 are symmetrically arranged on two sides of a three-stage freezing crystallizer 10.
The secondary crystal slurry discharged from the conical wall at the lower part of the secondary freezing crystallizer 8 is sent out by a secondary transfer pump B4, one part of the secondary crystal slurry returns to the secondary circulation pipe G7 through a secondary return pipe G9, the other part of the secondary crystal slurry is sent into the tertiary freezing crystallizer 10 through a secondary discharge pipe G10, and the tertiary circulation feed liquid is returned to the top inlet circulation of the tertiary freezing crystallizer 10 after being subjected to heat exchange and temperature reduction to a certain temperature through the tertiary freezing heat exchanger 9 under the action of the tertiary forced circulation pump B5. Wherein the temperature of the refrigerant inlet fed by the refrigerant feeding pipe G19 is-8 ℃, the temperature of the refrigerant outlet is-5 ℃ after heat exchange by the three-stage refrigeration heat exchanger 9, and the refrigerant is fed out by the refrigerant discharging pipe G20.
The conical bottom of the three-stage freezing crystallizer 10 is connected with one of the three-stage circulating pipes G12 through a three-stage blow-down pipe G14. The top of the secondary freezing crystallizer 8 is connected with the top of the tertiary freezing crystallizer 10 through a secondary balance pipe G11.
The crystal slurry at the bottom of the three-stage freezing crystallizer 10 is discharged through a crystal slurry discharging pipe G15, enters a centrifugal machine 11 in a self-flowing mode for solid-liquid separation, and solid disodium hydrogen phosphate discharged from the solid phase of the centrifugal machine 11 is conveyed to the outside through a screw conveyor 12. The mother liquor discharged from the liquid phase of the centrifuge 11 flows into the centrifugal mother liquor tank 13 through the gas-liquid separation pipe G16. The gas phase discharged from the top of the gas-liquid separation pipe G16 is discharged through the off-gas discharge pipe G13.
The disodium hydrogen phosphate mother liquor with the temperature of 0 ℃ temporarily stored in the centrifugal mother liquor tank 13 is discharged by a mother liquor discharge pump B6, and a part of the disodium hydrogen phosphate mother liquor is returned to the three-stage freezing crystallizer 10 through a mother liquor return pipe G18; the other part enters the upper inlet of the shell side of the secondary refrigeration heat exchanger 7 through a mother liquor recycling pipe G17, and fully exchanges heat with disodium hydrogen phosphate secondary circulating liquid of the pipe side, and the inlet temperature of the centrifugal mother liquor is 0 ℃, and the outlet temperature is 11.5 ℃, so that the consumption of the refrigerant can be reduced, and the energy is saved.
The centrifugal mother liquor at 11.5 ℃ flowing out of the outlet at the lower part of the shell pass of the secondary freezing heat exchanger 7 enters the inlet at the upper part of the shell pass of the primary freezing heat exchanger 5, and fully exchanges heat with the disodium hydrogen phosphate primary circulating liquid in the tube pass, and the outlet temperature of the centrifugal mother liquor is 21.5 ℃, so that the consumption of the refrigerant can be further reduced, and the energy is further saved.
And then, the centrifugal mother liquor at 21.5 ℃ flowing out of the shell side of the primary freezing heat exchanger 5 enters the cold side inlet of the second tube nest precooler 4, is discharged from the cold side outlet of the second tube nest precooler 4, enters the cold side inlet of the first tube nest precooler 3, is discharged from the cold side outlet of the first tube nest precooler 3, enters the cold side inlet of the second plate precooler 2, is discharged from the cold side outlet of the second plate precooler 2, is heated to 30.5 ℃, enters the cold side inlet of the first plate precooler 1, and is heated to 37.5 ℃ to be discharged.
The foregoing description of the preferred embodiments of the present utility model illustrates and describes the basic principles, main features and advantages of the present utility model, and is not intended to limit the scope of the present utility model, as it should be understood by those skilled in the art that the present utility model is not limited to the above-described embodiments. In addition to the embodiments described above, other embodiments of the utility model are possible without departing from the spirit and scope of the utility model. The utility model also has various changes and improvements, and all technical schemes formed by adopting equivalent substitution or equivalent transformation fall within the protection scope of the utility model. The scope of the utility model is defined by the appended claims and equivalents thereof. The technical features of the present utility model that are not described may be implemented by or using the prior art, and are not described herein.
Claims (8)
1. A gradient freeze crystallization device for disodium hydrogen phosphate wastewater, which is characterized by comprising:
the liquid outlet of the primary freezing crystallizer is connected with the inlet of the primary forced circulation pump through the primary circulation pipe;
The lower inlet of the tube side of the primary freezing heat exchanger is connected with the outlet of the primary forced circulation pump, and the upper outlet of the tube side is connected with the top inlet of the primary freezing crystallizer;
the liquid outlet of the secondary freezing crystallizer is connected with the inlet of the secondary forced circulation pump through a secondary circulation pipe;
the lower inlet of the tube side of the secondary freezing heat exchanger is connected with the outlet of the secondary forced circulation pump, and the upper outlet of the tube side is connected with the top inlet of the secondary freezing crystallizer;
The liquid outlet of the three-stage freezing crystallizer is connected with the inlet of the three-stage forced circulation pump through a three-stage circulation pipe;
The lower inlet of the tube pass of the three-stage freezing heat exchanger is connected with the outlet of the three-stage forced circulation pump, and the upper outlet of the tube pass is connected with the top inlet of the three-stage freezing crystallizer;
The primary freezing heat exchanger comprises a primary freezing heat exchanger, a primary freezing feed pipe, a primary material transferring pump, a primary discharging pipe, a primary freezing crystallizer, a secondary freezing heat exchanger and a secondary freezing heat exchanger, wherein a tube side outlet ascending pipe of the primary freezing heat exchanger is connected with the primary freezing feed pipe, a cone wall outlet of the primary freezing crystallizer is connected with the primary discharging pipe through the primary material transferring pump, and an outlet of the primary discharging pipe is connected with a tube side outlet ascending pipe of the secondary freezing heat exchanger; the cone wall outlet of the secondary freezing crystallizer is connected with a secondary discharging pipe through a secondary material transferring pump, and the outlet of the secondary discharging pipe is connected with the feeding inlet of the tertiary freezing crystallizer; and the cone wall outlet of the three-stage freezing crystallizer is connected with a crystal slurry discharging pipe.
2. The gradient freeze crystallization device for disodium hydrogen phosphate wastewater according to claim 1, wherein: the outlet of the crystal slurry discharging pipe is connected with the inlet of the centrifugal machine, and the solid phase outlet of the centrifugal machine is connected with the inlet of the screw conveyor; and a liquid phase outlet of the centrifugal machine is connected with an inlet of the centrifugal mother liquid tank through a gas-liquid separation pipe.
3. The gradient freeze crystallization device for disodium hydrogen phosphate wastewater according to claim 1, wherein: two groups of three-stage refrigeration heat exchangers, three-stage circulating pipes and three-stage forced circulating pumps are symmetrically arranged on two sides of the three-stage refrigeration crystallizer, shell side inlets of the three-stage refrigeration heat exchangers are respectively connected with a refrigerant feeding pipe, and shell side outlets of the three-stage refrigeration heat exchangers are respectively connected with a refrigerant discharging pipe.
4. The gradient freeze crystallization device for disodium hydrogen phosphate wastewater according to claim 2, wherein: the outlet of the centrifugal mother liquor tank is connected with the inlet of the mother liquor discharge pump, the outlet of the mother liquor discharge pump is connected with the shell side inlet of the secondary refrigeration heat exchanger through a mother liquor recycling pipe, and the shell side outlet of the secondary refrigeration heat exchanger is connected with the shell side inlet of the primary refrigeration heat exchanger.
5. The apparatus according to claim 4, wherein the outlet of the disodium hydrogen phosphate wastewater feed pipe is connected to the hot side inlet of a plate precooler, the hot side outlet of the plate precooler is connected to the hot side inlet of a column precooler, and the hot side outlet of the column precooler is connected to the primary freeze feed pipe.
6. The gradient freeze crystallization device for disodium hydrogen phosphate wastewater according to claim 5, wherein: the tube-in-tube precooler comprises a first tube-in-tube precooler and a second tube-in-tube precooler, wherein the hot side outlet of the plate-type precooler is connected with the hot side inlet of the first tube-in-tube precooler, the hot side outlet of the first tube-in-tube precooler is connected with the hot side inlet of the second tube-in-tube precooler, and the hot side outlet of the second tube-in-tube precooler is connected with the first-stage freezing feed pipe.
7. The gradient freeze crystallization device for disodium hydrogen phosphate wastewater according to claim 6, wherein: the plate precooler comprises a first plate precooler and a second plate precooler, an outlet of the disodium hydrogen phosphate wastewater feed pipe is connected with a hot side inlet of the first plate precooler, a hot side outlet of the first plate precooler is connected with a hot side inlet of the second plate precooler, and a hot side outlet of the second plate precooler is connected with a hot side inlet of the first column pipe precooler.
8. The gradient freeze crystallization device for disodium hydrogen phosphate wastewater according to claim 7, wherein: the shell side outlet of the primary refrigeration heat exchanger is connected with the cold side inlet of the second tube nest precooler, the cold side outlet of the second tube nest precooler is connected with the cold side inlet of the first tube nest precooler, the cold side outlet of the first tube nest precooler is connected with the cold side inlet of the second plate-type precooler, and the cold side outlet of the second plate-type precooler is connected with the cold side inlet of the first plate-type precooler.
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN221275311U true CN221275311U (en) | 2024-07-05 |
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