Anti-scaling continuous freezing crystallization device and method

Abstract

The invention discloses an anti-scaling continuous freezing crystallization device and method. The device comprises an A / B mixed salt dissolving tank, an A / B mixed salt water pretreatment tank, an ozone generator, a cyclone aerator, an MVR evaporator, a separation tank, a gradient freezing crystallization chamber, a mixed salt concentration tank, an A crystallization drying chamber and a B crystallization drying chamber. The A / B mixed salt dissolving tank is connected to the A / B mixed salt water pretreatment tank, the ozone generator is connected to the A / B mixed salt water pretreatment tank through the cyclone aerator, the A / B mixed salt water pretreatment tank is connected to the MVR evaporator, the MVR evaporator is connected to the gradient freezing crystallization chamber through the separation tank, the gradient freezing crystallization chamber is connected to the mixed salt concentration tank, the gradient freezing crystallization chamber and the MVR evaporator reflux the A / B mixed salt dissolving tank, and the mixed salt concentration tank and the gradient freezing crystallization chamber are respectively connected to the A crystallization drying chamber and the B crystallization drying chamber. The method can continuously separate and crystallize without scaling, and has a significant effect on the crystallization and purification of mixed salts of potassium chloride and sodium chloride. The purity of the obtained potassium chloride product is ≥90 (g / 100g), and the purity of the sodium chloride product is ≥95 (g / 100g).

Description

Technical Field

[0001] The invention relates to the technical field of freezing crystallization, and in particular to an anti-scaling continuous freezing crystallization device and method. Background Art

[0002] High-salt wastewater is the main source of waste salt, mainly involving pesticides, medicines, dyes, coking, metallurgy, new materials, chemical fibers and other industries, and the types mainly include potassium salt, sodium salt and mixed salt, etc. As the requirements for zero discharge of wastewater become higher and higher, the zero-discharge technology with high-salt wastewater freezing crystallization as the treatment end point has been increasingly recognized by the industry. However, in recent years, more and more combined freezing crystallization technologies have been applied to various types of wastewater treatment as sodium and potassium salt separation processes. The purity of sodium chloride and potassium chloride crystals in the salt separation process does not meet the standards, the recovery rate of finished salt is low, and the proportion of impure salt is large, which has become a major problem restricting its development.

[0003] Extracting potassium and sodium salts of a certain value from solid waste salt and high-salt industrial wastewater is an important problem that needs to be solved urgently in the comprehensive utilization of waste salt resources at this stage. At present, evaporation concentration, cooling and crystallization separation of industrial wastewater containing sodium chloride and potassium chloride are considered to be the most suitable processes for producing sodium chloride and potassium chloride. However, this combined process is greatly affected by impurities in waste salt, evaporation equipment and cooling devices, which makes it difficult to improve the purity of the product salt, and the energy consumption in the waste salt resource treatment process is large, and the heat loss and cold utilization rate are not high. Summary of the invention

[0004] The object of the present invention is to provide an anti-scaling continuous freezing crystallization device and method to solve the problems raised in the above background technology.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] An anti-scaling continuous freezing crystallization device and method comprises an A / B mixed salt dissolution tank, an A / B mixed salt water pretreatment tank, an ozone generator, a cyclone aerator, an MVR evaporator, a separation tank, a gradient freezing crystallization chamber, a mixed salt concentration tank, an A crystallization drying chamber and a B crystallization drying chamber. The A / B mixed salt dissolution tank is connected to the A / B mixed salt water pretreatment tank, one end of the cyclone aerator is connected to the ozone generator, and the end of the cyclone aerator away from the ozone generator is connected to the A / B mixed salt water pretreatment tank. The A / B mixed salt water pretreatment tank The pool is connected to the MVR evaporator, one end of the MVR evaporator flows into the A / B mixed salt dissolution pool, and the end of the MVR evaporator away from the A / B mixed salt dissolution pool flows into the separation tank, the separation tank is connected to the gradient freezing crystallization chamber, the gradient freezing crystallization chamber is connected to the mixed salt concentration tank, the gradient freezing crystallization chamber is connected to the A / B mixed salt dissolution pool, the mixed salt concentration tank and the gradient freezing crystallization chamber are respectively connected to the A crystallization drying chamber and the B crystallization drying chamber, and the separated A salt or B salt is respectively passed into the A crystallization drying chamber and the B crystallization drying chamber.

[0007] The microbubble enhanced ozonation technology performs organic matter removal pretreatment on the dissolved mixed salt water (taking potassium chloride and sodium chloride mixed salt water as an example), and the pretreated mixed salt water of potassium chloride and sodium chloride is subjected to MVR evaporation and concentration. The generated potassium chloride and sodium chloride concentrated liquid enters the separation tank, and the treated effluent generated by evaporation is returned to the A / B mixed salt dissolution tank. The concentrated first-level liquid of the mixed salt of potassium chloride and sodium chloride is pumped into the first-level horizontal freezing crystallizer for crystallization and concentration treatment to obtain potassium chloride crystals and sodium chloride solution. The potassium chloride crystals are sent to the A crystallization and drying chamber for freeze-drying to obtain potassium chloride product salt, and the sodium chloride first-level liquid is pumped into the second-level horizontal freezing crystallizer for crystallization separation. The generated ice cubes and ice residues are returned to the A / B mixed salt dissolution tank, and the saturated sodium chloride solution is sent to the B crystallization and drying chamber for crystallization and drying to obtain sodium chloride product salt.

[0008] Furthermore, the gradient freezing crystallization chamber includes a primary horizontal freezing crystallizer, a secondary horizontal freezing crystallizer, a primary liquid pump and a secondary liquid pump, the primary liquid pump is fixedly connected to the primary horizontal freezing crystallizer, the secondary liquid pump is fixedly connected to the secondary horizontal freezing crystallizer, one end of the primary horizontal freezing crystallizer is connected to the separation tank through the primary liquid pump, the end of the primary horizontal freezing crystallizer away from the separation tank is connected to the mixed salt concentration tank, the end of the mixed salt concentration tank away from the primary horizontal freezing crystallizer is connected to the secondary horizontal freezing crystallizer through the secondary liquid pump, and the end of the secondary horizontal freezing crystallizer away from the mixed salt concentration tank is connected to the A / B mixed salt dissolution tank; the mixed salt concentrate is pumped into the primary horizontal freezing crystallizer to separate potassium chloride crystals and sodium chloride solution and send them to the mixed salt concentration tank, the sodium chloride solution in the mixed salt concentration tank is pumped into the secondary horizontal freezing crystallizer, and the ice cubes and ice residues are refluxed to the A / B mixed salt dissolution tank.

[0009] Furthermore, the one-stage horizontal freezing crystallizer includes a rotating module, a centrifugal spiral scraper, a pneumatic centrifugal nozzle, a material layer controller, a liquid outlet, an air outlet, a compressor, a material outlet and a main barrel, the rotating module is connected to the main barrel, the rotating module rotates on the main barrel, a plurality of centrifugal spiral scrapers are arranged on the rotating module, the centrifugal spiral scrapers are spaced at equal intervals, a plurality of pneumatic centrifugal nozzles are arranged on the rotating module, the material layer controller is connected to the main barrel, the material layer controller is fixed on the main barrel, a through hole is arranged on the side of the main barrel to connect to the liquid outlet, one end of the liquid outlet passes through the main barrel and the material layer controller, a through hole is arranged on the side of the main barrel away from the liquid outlet to connect to the air outlet, and the air outlet One end of the outlet passes through the main barrel, a compressor is arranged at the end of the main barrel away from the outlet, the compressor is connected to the rotating module, the compressor is sequentially connected to the oil separator, the air-cooled condenser, the jacket liquid storage tank, the filter and the expansion valve, and finally connected to the pneumatic centrifugal nozzle, the outlet is arranged at one end of the rotating module close to the outlet, the end of the rotating module away from the outlet is connected to the primary liquid pump, and the end of the liquid outlet away from the rotating module is connected to the mixed salt concentration tank; the rotating module can pressurize the feed liquid through the air inlet jacket, so that the feed liquid is evenly distributed in the jacket and forms a spray, which can quickly crystallize on the inner wall of the main barrel; the crystals can be quickly discharged under the action of the centrifugal spiral scraper to avoid scaling of the crystals on the inner side of the main barrel.

[0010] Furthermore, the rotating module includes an air intake jacket, a feed jacket and a main shaft, the air intake jacket is arranged on the main shaft, the air intake jacket is fixedly connected to the compressor, the feed jacket is arranged on the main shaft, the feed jacket is fixedly connected to the pneumatic centrifugal nozzle, the feed jacket is provided with a feed port connected to a primary liquid pump, and the main shaft is connected to a discharge port at one end away from the primary liquid pump; in order to pressurize the solution in the feed jacket, the air intake jacket drives the centrifugal spiral scraper to rotate and collect crystals.

[0011] Furthermore, the centrifugal spiral scraper includes a scraper hub, a blade and a cone, the scraper hub and the blade are arranged on the cone, and the cone is fixedly connected to the main shaft through the scraper hub; the cone is used to fix the blade, and the blade is used to collect crystals to prevent the crystals from scaling on the inner side of the main cylinder.

[0012] Furthermore, the pneumatic centrifugal nozzle includes an atomizing nozzle, a liquid inlet and an air inlet, one end of the liquid inlet is connected to the atomizing nozzle, the end of the liquid inlet away from the atomizing nozzle is connected to the feed jacket, one end of the air inlet is connected to the atomizing nozzle, and the end of the air inlet away from the atomizing nozzle is connected to the air inlet jacket; the atomizing nozzle evenly sprays the pressurized solution into the inner side of the main barrel to accelerate the crystallization of potassium chloride.

[0013] Furthermore, the secondary horizontal freezing crystallizer has the same structure as the primary horizontal freezing crystallizer. The feed jacket of the secondary horizontal freezing crystallizer is connected to the mixed salt concentration tank through a secondary liquid pump, and the discharge port of the secondary horizontal freezing crystallizer is connected to the A / B mixed salt dissolution tank; the secondary liquid pump is used to pump the mixed salt water into the feed jacket.

[0014] Further, the crystallization method comprises the following steps in the process of treating the A / B mixed brine:

[0015] S1: Microbubble enhanced ozonation technology is used to pre-treat the mixed brine dissolved in the A / B mixed brine pretreatment tank to remove organic matter: There are impurities in the A / B mixed brine that affect the purity of the solution. The mixed brine is removed by microbubble enhanced ozonation technology;

[0016] S2: The pretreated mixed salt water is placed in an MVR evaporator for MVR evaporation and concentration. The generated potassium chloride and sodium chloride concentrated solutions enter the separation tank, and the treated water generated by evaporation is returned to the A / B mixed salt dissolution tank: The MVR evaporator evaporates the water in the solution through high-temperature evaporation and returns it to the A / B mixed salt dissolution tank, and then the generated potassium chloride and sodium chloride concentrated solutions are passed into the separation tank;

[0017] S3: Pumping the mixed salt concentrate of potassium chloride and sodium chloride into a first-stage horizontal freezing crystallizer for crystallization and concentration treatment to obtain potassium chloride crystals and sodium chloride solution, and freeze-drying the potassium chloride crystals to obtain potassium chloride product salt: The mixed salt concentrate of potassium chloride and sodium chloride is pumped from the separation tank into the feed jacket at a pumping speed of 0.5L / min to 5L / min, and the mixed salt concentrate of potassium chloride and sodium chloride is uniformly sprayed into the inner side of the main barrel for crystallization through a pneumatic centrifugal nozzle, and the crystallization temperature is 20 to 35°C. The crystallizer is provided with a centrifugal spiral scraper at a stirring speed of 50 to 100r / min to separate potassium chloride crystals and sodium chloride solution, and the potassium chloride crystals are passed into a crystallization drying chamber A for freeze-drying to obtain potassium chloride product salt, and the sodium chloride solution is passed into a mixed salt concentration tank;

[0018] S4: Pump the sodium chloride solution into a secondary horizontal freezing crystallizer for crystallization separation, and the generated ice cubes and ice slag are returned to the A / B mixed salt dissolving tank. The generated sodium chloride saturated solution is crystallized and dried to obtain product salt: the sodium chloride solution is pumped from the mixed salt concentration tank into the feed jacket of the secondary horizontal freezing crystallizer at a pumping speed of 0.1L / min~2L / min. The sodium chloride solution is evenly sprayed into the inner side of the main barrel for crystallization through a pneumatic centrifugal nozzle. The crystallization temperature is -5~0℃. The crystallizer is equipped with a centrifugal spiral scraper with a stirring speed of 50~100r / min. The ice cubes, ice slag and sodium chloride saturated solution are separated, and the ice cubes and ice slag are transported to the A / B mixed salt dissolving tank. The sodium chloride saturated solution is passed into the B crystallization drying chamber to obtain sodium chloride product salt after freeze drying at -20~-40℃.

[0019] Furthermore, in step S1, the microbubble enhanced ozonation technology uses an air source as the gas source of the ozone generator, the outlet of the ozone generator is connected to a cyclone aerator, the air inlet diameter is DN20, the pipeline pressure level is PN10, the cyclone aerator is placed at the bottom of the A / B mixed salt water pretreatment tank, the microbubble particle size is adjusted to 0.1-0.6 μm, the bubble density is 0.1-0.6 g / cm3, and the ozone dosage is 8-15 mg / m 3 ;.

[0020] Furthermore, in step S2, under the mother liquor circulation operation mode, the atmospheric evaporation temperature of the MVR evaporator is 75-95°C, the steam volume is 80%-85%, and the treated water produced by evaporation is returned to the A / B mixed salt dissolution tank, and the mixed salt concentrate enters the separation tank.

[0021] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: a cyclone aerator is used to achieve controllable adjustment of the particle size of ozone bubbles, thereby improving the utilization efficiency of ozone and achieving efficient removal of organic matter in wastewater; a gradient freezing crystallization chamber is composed of a two-stage water pump and a two-stage horizontal freezing crystallizer, and a screw scraper is provided inside the crystallizer, which can effectively improve the heat exchange efficiency on the one hand and prevent the crystallized solid from clogging the crystallizer on the other hand, thereby improving the solid-liquid separation efficiency; and the crystallization temperature range of the two-stage horizontal freezing crystallizer is a gradient distribution, and this technology can effectively improve the heat exchange efficiency of cooling crystallization, reduce the loss of cold capacity, and achieve continuous separation and purification of potassium chloride and sodium chloride. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0023] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0024] Figure 2 It is a schematic diagram of the structure of a one-stage horizontal freezing crystallizer of the present invention;

[0025] Figure 3 It is a schematic diagram of the structure of the centrifugal spiral scraper of the present invention;

[0026] Figure 4 It is a schematic diagram of the structure of the pneumatic centrifugal nozzle of the present invention;

[0027] In the figure: 1. A / B mixed salt dissolution tank; 2. A / B mixed salt water pretreatment tank; 3. Ozone generator; 4. Cyclone aerator; 5. MVR evaporator; 6. Separation tank; 7. Gradient freezing crystallization chamber; 71. One-stage horizontal freezing crystallizer; 711. Rotating module; 7111. Air inlet jacket; 7112. Feed jacket; 7113. Main shaft; 712. Centrifugal spiral scraper; 7121. Scraper hub; 7122, blade; 7123, cone; 713, pneumatic centrifugal nozzle; 7131, atomizing nozzle; 7132, liquid inlet; 7133, air inlet; 714, material layer controller; 715, liquid outlet; 716, air outlet; 717, compressor; 718, material outlet; 719, main barrel; 72, two-stage horizontal freezing crystallizer; 73, primary liquid pump; 74, secondary liquid pump; 8, mixed salt concentration tank. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] The present invention provides a technical solution:

[0030] like Figure 1 As shown, taking potassium chloride and sodium chloride mixed salt as an example, an anti-scaling continuous freezing crystallization device includes an A / B mixed salt dissolution tank 1, an A / B mixed salt water pretreatment tank 2, an ozone generator 3, a cyclone aerator 4, an MVR evaporator 5, a separation tank 6, a gradient freezing crystallization chamber 7, a mixed salt concentration tank 8, an A crystallization drying chamber 9 and a B crystallization drying chamber 10. The A / B mixed salt dissolution tank 1 is connected to the A / B mixed salt water pretreatment tank 2, one end of the cyclone aerator 4 is connected to the ozone generator 3, and the end of the cyclone aerator 4 away from the ozone generator 3 is connected to the A / B mixed salt water pretreatment pool 2, the A / B mixed salt water pretreatment pool 2 is connected to the MVR evaporator 5, one end of the MVR evaporator 5 refluxes into the A / B mixed salt dissolution pool 1, the MVR evaporator 5 flows into the separation tank 6 away from the end of the A / B mixed salt dissolution pool 1, the separation tank 6 is connected to the gradient freezing crystallization chamber 7, the gradient freezing crystallization chamber 7 is connected to the mixed salt concentration tank 8, the gradient freezing crystallization chamber 7 is connected to the A / B mixed salt dissolution pool 1, the mixed salt concentration tank 8 and the gradient freezing crystallization chamber 7 are respectively connected to the A crystallization drying chamber 9 and the B crystallization drying chamber 10.

[0031] The A / B mixed salt dissolving tank 1 passes the mixed salt water into the A / B mixed salt water pretreatment tank 2, the cyclone aerator 4 strengthens the ozone oxidation of the ozone generator 3, and adopts the micro-bubble enhanced ozonation technology to perform organic impurity removal pretreatment on the mixed salt water, the MVR evaporator 5 performs MVR evaporation and concentration on the treated mixed salt water, the generated potassium chloride and sodium chloride concentrated solution enters the separation tank 6, the treated effluent generated by evaporation flows back to the A / B mixed salt dissolving tank 1, the potassium chloride and sodium chloride concentrated solution flows from the separation tank 6 into the gradient freezing crystallization chamber 7 to separate potassium chloride crystals and sodium chloride solution, the mixed salt concentration tank 8 separates the potassium chloride crystals and sends them into the A crystallization drying chamber 9, and the potassium chloride product salt is obtained after freeze-drying, the mixed salt concentration tank 8 passes the separated sodium chloride solution into the gradient freezing crystallization chamber 7 to separate ice cubes, ice slag and sodium chloride saturated solution, the generated ice cubes and ice slag flow back to the A / B mixed salt dissolving tank 1, and the sodium chloride saturated solution is sent to the B crystallization drying chamber 10.

[0032] like Figure 1 As shown, the gradient freezing crystallization chamber 7 includes a primary horizontal freezing crystallizer 71, a secondary horizontal freezing crystallizer 72, a primary liquid pump 73 and a secondary liquid pump 74, the primary liquid pump 73 is fixedly connected to the primary horizontal freezing crystallizer 71, the secondary liquid pump 74 is fixedly connected to the secondary horizontal freezing crystallizer 72, one end of the primary horizontal freezing crystallizer 71 is connected to the separation tank 6 through the primary liquid pump 73, the end of the primary horizontal freezing crystallizer 71 away from the separation tank 6 is connected to the mixed salt concentration tank 8, the end of the mixed salt concentration tank 8 away from the primary horizontal freezing crystallizer 71 is connected to the secondary horizontal freezing crystallizer 72 through the secondary liquid pump 74, and the end of the secondary horizontal freezing crystallizer 72 away from the mixed salt concentration tank 8 is connected to the A / B mixed salt dissolution tank 1.

[0033] The potassium chloride and sodium chloride concentrates in the separation tank 6 are pumped into a first-stage horizontal freezing crystallizer 71 through a first-stage liquid pump 73. The first-stage horizontal freezing crystallizer 71 separates potassium chloride crystals from sodium chloride solution. The mixed salt concentration tank 8 pumps the sodium chloride solution into a second-stage horizontal freezing crystallizer 72 through a second-stage liquid pump 74 to separate ice cubes, ice residue and saturated sodium chloride solution. Connecting multiple stages of freezing crystallizers in series can improve heat exchange efficiency, and can adjust the freezing crystallization temperature by gradient to achieve the purpose of staged crystallization of components, thereby achieving continuous quality-based crystallization of mixed salt.

[0034] like Figure 2As shown, the one-stage horizontal freezing crystallizer 71 includes a rotating module 711, a centrifugal spiral scraper 712, a pneumatic centrifugal nozzle 713, a material layer controller 714, a liquid outlet 715, an air outlet 716, a compressor 717, a material outlet 718 and a main barrel 719, wherein the rotating module 711 is connected to the main barrel 719, the rotating module 711 rotates on the main barrel 719, a plurality of centrifugal spiral scrapers 712 are arranged on the rotating module 711, and the spacing between the centrifugal spiral scrapers 712 is equal, a plurality of pneumatic centrifugal nozzles 713 are arranged on the rotating module 711, a material layer controller 714 is connected to the main barrel 719, the material layer controller 714 is fixed on the main barrel 719, and a through hole is arranged on the side of the main barrel 719 to connect the liquid outlet 71 5. One end of the liquid outlet 715 passes through the main barrel 719 and the material layer controller 714. A through hole is arranged on the side of the main barrel 719 away from the liquid outlet 715 to connect with the gas outlet 716. One end of the gas outlet 716 passes through the main barrel 719. A compressor 717 is arranged on the end of the main barrel 719 away from the material outlet 718. The compressor 717 is connected to the rotating module 711. The compressor 717 is sequentially connected to the oil separator, the air-cooled condenser, the jacketed liquid storage tank, the filter and the expansion valve, and finally connected to the pneumatic centrifugal nozzle 713. The material outlet 718 is arranged on the end of the rotating module 711 close to the liquid outlet 715. The end of the rotating module 711 away from the material outlet 718 is connected to the primary liquid pump 73. The end of the liquid outlet 715 away from the rotating module 711 is connected to the mixed salt concentration tank 8.

[0035] The rotating module 711 passes the mixed brine into the pneumatic centrifugal nozzle 713, and passes the gas into the compressor 717. The compressor 717 is connected to the oil separator, the air-cooled condenser, the jacket liquid storage tank, the filter and the expansion valve in sequence, and finally connected to the pneumatic centrifugal nozzle 713 to pressurize the pneumatic centrifugal nozzle 713 so that the mixed brine is evenly distributed in the jacket and forms a spray, which can quickly crystallize on the inner wall of the main barrel 719. The material layer controller 714 isolates the potassium chloride crystals and the sodium chloride solution. The liquid outlet 715 discharges the solution in the material layer controller 714, and the gas outlet 716 discharges the gas to maintain the air pressure. The centrifugal spiral scraper 712 collects the potassium chloride crystals through the rotating module 711 to avoid scaling of the crystals on the inner side of the main barrel 719, thereby effectively preventing the condenser from being blocked and improving the continuous crystallization effect. The potassium chloride crystals are discharged from the main barrel 719 through the discharge port 718.

[0036] like Figure 2As shown, the rotating module 711 includes an air intake jacket 7111, a feed jacket 7112 and a main shaft 7113. The air intake jacket 7111 is arranged on the main shaft 7113, and the air intake jacket 7111 is fixedly connected to the compressor 717. The feed jacket 7112 is arranged on the main shaft 7113, and the feed jacket 7112 is fixedly connected to the pneumatic centrifugal nozzle 713. One end of the feed jacket 7112 is connected to the primary liquid pump 73, and the end of the main shaft 7113 away from the primary liquid pump 73 is connected to the discharge port 718.

[0037] The main shaft 7113 drives the centrifugal spiral scraper 712 to rotate, and the feed jacket 7112 passes the mixed brine into the pneumatic centrifugal nozzle 713. The air intake jacket 7111 passes gas to the compressor 717 for pressurization, so that the mixed brine is evenly distributed in the jacket and forms a spray, which can quickly crystallize on the inner wall of the main cylinder 719.

[0038] like Figure 3 As shown, the centrifugal spiral scraper 712 according to claim 4 includes a scraper hub 7121, a blade 7122 and a cone 7123, the scraper hub 7121 and the blade 7122 are arranged on the cone 7123, and the scraper hub 7121 is fixedly connected to the main shaft 7113.

[0039] The cone 7123 is fixed on the main shaft 7113 through the scraper hub 7121. The main shaft 7113 drives the cone 7123 to rotate, and the blade 7122 separates the crystals on the inner wall of the main cylinder 719.

[0040] like Figure 4 As shown, the pneumatic centrifugal nozzle 713 according to claim 5 includes an atomizing nozzle 7131, a liquid inlet 7132 and an air inlet 7133, one end of the liquid inlet 7132 is connected to the atomizing nozzle 7131, and the end of the liquid inlet 7132 away from the atomizing nozzle 7131 is connected to the feed jacket 7112, one end of the air inlet 7133 is connected to the atomizing nozzle 7131, and the end of the air inlet 7133 away from the atomizing nozzle 7131 is connected to the air inlet jacket 7111.

[0041] The gas at the air inlet 7133 pressurizes the mixed salt water at the liquid inlet 7132, and the mixed salt water is atomized and sprayed out evenly through the atomizing nozzle 7131, thereby increasing the crystallization speed.

[0042] like Figure 1 , Figure 2 As shown, the secondary horizontal freezing crystallizer 72 has the same structure as the primary horizontal freezing crystallizer 71. The feed jacket 7112 of the secondary horizontal freezing crystallizer 72 is connected to the mixed salt concentration tank 8 through the secondary liquid pump 74, and the discharge port 718 of the secondary horizontal freezing crystallizer 72 is connected to the A / B mixed salt dissolution tank 1.

[0043] The sodium chloride solution in the mixed salt concentration tank 8 is pumped into the feed jacket 7112 of the secondary horizontal freezing crystallizer 72 by the secondary liquid pump 74, and is evenly sprayed out through the pneumatic centrifugal nozzle 713, attached to the inner wall of the main tube 719 for crystallization, and finally ice cubes, ice residue and saturated sodium chloride solution are separated. The ice cubes and ice residue are transported to the A / B mixed salt dissolution tank 1 from the discharge port 718, and the saturated sodium chloride solution is output from the liquid inlet 7132.

[0044] like Figure 1 As shown, the crystallization method comprises the following steps in the process of treating a mixed brine of potassium chloride and sodium chloride:

[0045] S1: Use microbubble enhanced ozonation technology to pre-treat the mixed brine dissolved in the A / B mixed brine pre-treatment tank 2 to remove organic matter: There are impurities in the A / B mixed brine that affect the purity of the solution, and the mixed brine is removed by microbubble enhanced ozonation technology;

[0046] S2: The pretreated mixed salt water is placed in the MVR evaporator 5 for MVR evaporation and concentration, and the generated potassium chloride and sodium chloride concentrated solution enters the separation tank 6, and the treated water generated by evaporation is returned to the A / B mixed salt dissolution tank 1: The MVR evaporator evaporates the water in the solution through high-temperature evaporation and returns it to the A / B mixed salt dissolution tank 1, and then the generated potassium chloride and sodium chloride concentrated solution is passed into the separation tank 6;

[0047] S3: The mixed salt concentrate of potassium chloride and sodium chloride is pumped into a first-stage horizontal freezing crystallizer 71 for crystallization and concentration treatment to obtain potassium chloride crystals and sodium chloride solution. The potassium chloride crystals are freeze-dried to obtain potassium chloride product salt: The mixed salt concentrate of potassium chloride and sodium chloride is pumped from the separation tank 6 into the feed jacket 7112 at a pumping speed of 0.5L / min to 5L / min. The mixed salt concentrate of potassium chloride and sodium chloride is uniformly sprayed into the inner side of the main barrel 719 through a pneumatic centrifugal nozzle 713 for crystallization. The crystallization temperature is 20 to 35°C. The crystallizer is provided with a centrifugal spiral scraper 712 at a stirring speed of 50 to 100r / min to separate potassium chloride crystals and sodium chloride solution. The potassium chloride crystals are passed into a crystallization drying chamber A 9 for freeze-drying to obtain potassium chloride product salt. The sodium chloride solution is passed into the mixed salt concentration tank 8;

[0048] S4: Pump the sodium chloride solution into the secondary horizontal freezing crystallizer 72 for crystallization separation, and the generated ice cubes and ice slag are returned to the A / B mixed salt dissolving tank 1. The generated sodium chloride saturated solution is crystallized and dried to obtain product salt: the sodium chloride solution is pumped from the mixed salt concentration tank 8 into the feed jacket 7112 of the secondary horizontal freezing crystallizer 72, and the pumping speed is 0.1L / min~2L / min. The sodium chloride solution is evenly sprayed into the inner side of the main barrel 719 through the pneumatic centrifugal nozzle 713 for crystallization. The crystallization temperature is -5~0℃. The crystallizer is equipped with a centrifugal spiral scraper 712, and the stirring speed is 50~100r / min. The ice cubes, ice slag and sodium chloride saturated solution are separated, and the ice cubes and ice slag are transported to the A / B mixed salt dissolving tank 1. The sodium chloride saturated solution is passed into the B crystallization drying chamber 10, and the sodium chloride product salt is obtained after freeze drying at -20~-40℃.

[0049] like Figure 1 As shown, in the step S1, the microbubble enhanced ozonation technology adopts an air source as the air source of the ozone generator 3, the outlet of the ozone generator 3 is connected to the cyclone aerator 4, the air inlet diameter of which is DN20, the pipeline pressure level is PN10, the cyclone aerator 4 is placed at the bottom of the A / B mixed salt water pretreatment tank 2, the microbubble particle size is adjusted to 0.1-0.6 μm, the bubble density is 0.1-0.6 g / cm3, and the ozone dosage is 8-15 mg / m 3 .

[0050] The cyclone aerator 4 is used to control the particle size of the ozone bubbles produced by the ozone generator 3, thereby improving the utilization efficiency of ozone and achieving efficient removal of organic matter from wastewater. The process uses air as the source of ozone, has low investment cost, simple operation, and is easy to modularize.

[0051] like Figure 1 As shown, in the step S2, under the mother liquor circulation operation mode, the atmospheric evaporation temperature of the MVR evaporator 5 is 75-95°C, the steam volume is 80%-85%, and the treated water produced by evaporation is returned to the A / B mixed salt dissolution tank 1, and the mixed salt concentrate enters the separation tank 6.

[0052] The MVR evaporator 5 performs MVR evaporation and concentration treatment on the mixed salt water, and the treated water produced by evaporation flows back to the A / B mixed salt dissolution tank 1 , and the produced mixed salt concentrated liquid enters the separation tank 6 .

[0053] The working principle of the present invention is as follows: the organic matter in the mixed brine of potassium chloride and sodium chloride is efficiently removed by using microbubble enhanced ozonation technology, thereby improving the purity of the mixed brine; based on the centrifugal spiral scraper discharge design of the horizontal freezing crystallizer, the purpose of gradient freezing crystallization is achieved under the advantage of the high heat exchange efficiency of the independently developed two-stage freezing crystallization arrangement, which, on the one hand, improves the utilization efficiency of the cold amount and avoids the scaling and clogging of the freezing cylinder; on the other hand, it realizes the continuous quality separation crystallization purification of the mixed salt of potassium chloride and sodium chloride.

[0054] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0055] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An anti-scaling continuous freezing crystallization device, characterized in that: The device comprises an A / B mixed salt dissolution tank (1), an A / B mixed salt water pretreatment tank (2), an ozone generator (3), a cyclone aerator (4), an MVR evaporator (5), a separation tank (6), a gradient freezing crystallization chamber (7), a mixed salt concentration tank (8), an A crystallization drying chamber (9) and a B crystallization drying chamber (10), wherein the A / B mixed salt dissolution tank (1) is connected to the A / B mixed salt water pretreatment tank (2), one end of the cyclone aerator (4) is connected to the ozone generator (3), and one end of the cyclone aerator (4) away from the ozone generator (3) is connected to the A / B mixed salt water pretreatment tank (2), and the A / B mixed salt dissolution tank (1) is connected to the A / B mixed salt water pretreatment tank (2). A / B mixed salt water pretreatment pool (2) is introduced into an MVR evaporator (5), one end of the MVR evaporator (5) is refluxed into the A / B mixed salt dissolution pool (1), and one end of the MVR evaporator (5) away from the A / B mixed salt dissolution pool (1) flows into a separation tank (6), the separation tank (6) is connected to a gradient freezing crystallization chamber (7), the gradient freezing crystallization chamber (7) is connected to a mixed salt concentration tank (8), the gradient freezing crystallization chamber (7) is connected to the A / B mixed salt dissolution pool (1), and the mixed salt concentration tank (8) and the gradient freezing crystallization chamber (7) are respectively connected to an A crystallization drying chamber (9) and a B crystallization drying chamber (10); The gradient freezing crystallization chamber (7) comprises a primary horizontal freezing crystallizer (71), a secondary horizontal freezing crystallizer (72), a primary liquid pump (73) and a secondary liquid pump (74); The one-stage horizontal freezing crystallizer (71) comprises a rotating module (711), a centrifugal spiral scraper (712), a pneumatic centrifugal nozzle (713), a material layer controller (714), a liquid outlet (715), a gas outlet (716), a compressor (717), a material outlet (718) and a main barrel (719); the rotating module (711) is connected to the main barrel (719); the rotating module (711) rotates on the main barrel (719); a plurality of centrifugal spiral scrapers (712) are arranged on the rotating module (711); the centrifugal spiral scrapers (712) are spaced at equal intervals; a plurality of pneumatic centrifugal nozzles (713) are arranged on the rotating module (711); the material layer controller (714) is connected to the main barrel (719); the material layer controller (714) is fixed on the main barrel (719); and a through hole is arranged on the side of the main barrel (719) to connect to the liquid outlet (715). One end of the liquid outlet (715) passes through the main cylinder (719) and the material layer controller (714); a through hole is provided on the side of the main cylinder (719) away from the liquid outlet (715) to connect to the gas outlet (716); one end of the gas outlet (716) passes through the main cylinder (719); a compressor (717) is provided on the end of the main cylinder (719) away from the material outlet (718); the compressor (717) is connected to the rotating module (711) to compress The machine (717) is connected in sequence to an oil separator, an air-cooled condenser, a jacketed liquid storage tank, a filter and an expansion valve, and finally to a pneumatic centrifugal nozzle (713). An outlet (718) is provided at one end of the rotating module (711) close to the liquid outlet (715). An end of the rotating module (711) away from the outlet (718) is connected to a primary liquid pump (73). An end of the liquid outlet (715) away from the rotating module (711) is connected to a mixed salt concentration tank (8).

2. The anti-scaling continuous freezing crystallization device according to claim 1, characterized in that: The first-level liquid pump (73) is fixedly connected to the first-level horizontal freezing crystallizer (71), and the second-level liquid pump (74) is fixedly connected to the second-level horizontal freezing crystallizer (72); one end of the first-level horizontal freezing crystallizer (71) is connected to the separation tank (6) via the first-level liquid pump (73); one end of the first-level horizontal freezing crystallizer (71) away from the separation tank (6) is connected to the mixed salt concentration tank (8); one end of the mixed salt concentration tank (8) away from the first-level horizontal freezing crystallizer (71) is connected to the second-level freezing crystallizer (72) via the second-level liquid pump (74); and one end of the second-level freezing crystallizer (72) away from the mixed salt concentration tank (8) is connected to the A / B mixed salt dissolution tank (1).

3. The anti-scaling continuous freezing crystallization device according to claim 2, characterized in that: The rotating module (711) comprises an air intake jacket (7111), a feed jacket (7112) and a main shaft (7113); the air intake jacket (7111) is arranged on the main shaft (7113); the air intake jacket (7111) is fixedly connected to the compressor (717); the feed jacket (7112) is arranged on the main shaft (7113); the feed jacket (7112) is fixedly connected to the pneumatic centrifugal nozzle (713); the feed jacket (7112) is provided with a feed port connected to a primary liquid pump (73); and the main shaft (7113) is connected to a discharge port (718) at one end away from the primary liquid pump (73).

4. The anti-scaling continuous freezing crystallization device according to claim 3, characterized in that: The centrifugal spiral scraper (712) comprises a scraper hub (7121), a blade (7122) and a cone (7123); the scraper hub (7121) and the blade (7122) are arranged on the cone (7123); and the cone (7123) is fixedly connected to the main shaft (7113) via the scraper hub (7121).

5. The anti-scaling continuous freezing crystallization device according to claim 4, characterized in that: The pneumatic centrifugal nozzle (713) comprises an atomizing nozzle (7131), a liquid inlet (7132) and an air inlet (7133); one end of the liquid inlet (7132) is connected to the atomizing nozzle (7131); one end of the liquid inlet (7132) away from the atomizing nozzle (7131) is connected to a feed jacket (7112); one end of the air inlet (7133) is connected to the atomizing nozzle (7131); and one end of the air inlet (7133) away from the atomizing nozzle (7131) is connected to an air inlet jacket (7111).

6. The anti-scaling continuous freezing crystallization device according to claim 5, characterized in that: The secondary horizontal freezing crystallizer (72) has the same structure as the primary horizontal freezing crystallizer (71); the feed jacket (7112) of the secondary horizontal freezing crystallizer (72) is connected to the mixed salt concentration tank (8) via a secondary liquid pump (74); and the discharge port (718) of the secondary horizontal freezing crystallizer (72) is connected to the A / B mixed salt dissolution tank (1).

7. The crystallization method of the anti-scaling continuous freezing crystallization device according to claim 6, characterized in that: The crystallization method comprises the following steps in the process of treating a mixed brine of potassium chloride and sodium chloride: S1: using microbubble enhanced ozonation technology to pre-treat the mixed brine dissolved in the potassium chloride and sodium chloride mixed brine pre-treatment tank (2) to remove organic matter; S2: The pretreated mixed salt water is placed in an MVR evaporator (5) for MVR evaporation and concentration. The generated potassium chloride and sodium chloride concentrates enter a separation tank (6). The treated effluent generated by evaporation is returned to the A / B mixed salt dissolution tank (1); S3: The mixed salt concentrate of potassium chloride and sodium chloride is pumped into a first-stage horizontal freezing crystallizer (71) for crystallization and concentration treatment to obtain potassium chloride crystals and sodium chloride solution. The potassium chloride crystals are freeze-dried to obtain potassium chloride product salt. The mixed salt concentrate of potassium chloride and sodium chloride is pumped from the separation tank (6) into the feed jacket (7112) at a pumping speed of 0.5 L / min to 5 L / min. The mixed salt concentrate of potassium chloride and sodium chloride is uniformly sprayed into the inner side of the main barrel (719) for crystallization through a pneumatic centrifugal nozzle (713). The crystallizer is provided with a centrifugal spiral scraper (712) at a stirring speed of 50 to 100 r / min to separate potassium chloride crystals and sodium chloride solution. The potassium chloride crystals are passed into a crystallization drying chamber A for freeze-drying to obtain potassium chloride product salt. The sodium chloride solution is passed into a mixed salt concentration tank; S4: The sodium chloride solution is pumped into a secondary horizontal freezing crystallizer (72) for crystallization separation. The ice cubes and ice slag generated are returned to the A / B mixed salt dissolving tank (1). The generated sodium chloride saturated solution is crystallized and dried to obtain product salt. The sodium chloride solution is pumped from the mixed salt concentration tank (8) into the feed jacket (7112) of the secondary horizontal freezing crystallizer (72) at a pumping speed of 0.1 L / min to 2 L / min. The sodium chloride solution is uniformly sprayed into the inner side of the main barrel (719) for crystallization through a pneumatic centrifugal nozzle (713). The crystallizer is provided with a centrifugal spiral scraper (712) at a stirring speed of 50 to 100 r / min. The ice cubes, ice slag and sodium chloride saturated solution are separated. The ice cubes and ice slag are transported to the A / B mixed salt dissolving tank. The sodium chloride saturated solution is passed into the B crystallization drying chamber and freeze-dried at -20 to -40°C to obtain sodium chloride product salt.

8. The crystallization method of the anti-scaling continuous freezing crystallization device according to claim 7, characterized in that: In the step S1, the microbubble enhanced ozonation technology uses an air source as the air source of the ozone generator (3); the outlet of the ozone generator (3) is connected to the cyclone aerator (4); the air inlet diameter of the ozone generator (3) is DN20, and the pipeline pressure level is PN10; the cyclone aerator (4) is placed at the bottom of the A / B mixed salt water pretreatment tank (2); the microbubble particle size is adjusted to 0.1-0.6 μm, the bubble density is 0.1-0.6 g / cm3, and the ozone dosage is 8-15 mg / m3; in the step S2, under the mother liquor circulation operation mode, the MVR evaporator (5) has a normal pressure evaporation temperature of 75-95°C, and the steam water volume is 80%-85%. The treated effluent generated by evaporation is returned to the A / B mixed salt dissolution tank (1), and the mixed salt concentrate enters the separation tank (6).

9. The crystallization method of the anti-scaling continuous freezing crystallization device according to claim 7, characterized in that: Application of resource recovery treatment of mixed salt wastewater containing sodium chloride and potassium chloride generated during antibiotic production and fly ash washing.

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