Anti-scaling continuous freezing crystallization device and method

Abstract

An anti-scaling continuous freezing crystallization device and method. The device comprises an A / B mixed salt dissolution tank (1), an A / B mixed salt solution 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 crystal drying chamber (9) and a B crystal drying chamber (10). The A / B mixed salt dissolution tank (1) feeds to the A / B mixed salt solution pretreatment tank (2). The ozone generator (3) is connected to the A / B mixed salt solution pretreatment tank (2) via the cyclone aerator (4). The A / B mixed salt solution pretreatment tank (2) is connected to the MVR evaporator (5). The MVR evaporator (5) is connected to the gradient freezing crystallization chamber (7) via the separation tank (6). The gradient freezing crystallization chamber (7) is connected to the mixed salt concentration tank (8), and the gradient freezing crystallization chamber (7) and the MVR evaporator (5) reflux to the A / B mixed salt dissolution tank (1). The mixed salt concentration tank (8) and the gradient freezing crystallization chamber (7) are respectively connected to the A crystal drying chamber (9) and the B crystal drying chamber (10). The method can realize continuous fractional crystallization and is resistant to scaling, and exhibits significant crystallization and purification effects on potassium chloride and sodium chloride mixed salts. The purity of an obtained potassium chloride product is ≥90 (g / 100 g) and the purity of an obtained sodium chloride product is ≥95 (g / 100 g).

Description

Anti-fouling continuous freeze crystallization device and method TECHNICAL FIELD

[0001] The present application relates to the technical field of freeze crystallization, in particular to an anti-fouling continuous freeze crystallization device and method. BACKGROUND

[0002] High-salinity wastewater is the main source of waste salt, mainly involving pesticide, pharmaceutical, dye, coking, metallurgy, new material, chemical fiber and other industries, and mainly including potassium salt, sodium salt and mixed salt. With the increasing demand for wastewater zero discharge, the freeze crystallization and salt separation technology for high-salinity wastewater has been increasingly recognized by the industry as a zero discharge technology, but with the increasing application of combined freeze crystallization technology in various wastewater treatment in recent years, the purity of sodium chloride and potassium chloride in the salt separation process does not meet the standards, the recovery rate of finished salt is low, and the proportion of impurities is large, which has become a major problem restricting its development.

[0003] Extracting valuable potassium salt and sodium salt from solid waste salt and high-salinity industrial wastewater is an important problem to be solved in the comprehensive utilization of waste salt resources at the present stage. At present, evaporation concentration, cooling and crystallization separation of industrial wastewater containing sodium chloride and potassium chloride are considered to be a suitable process for producing sodium chloride and potassium chloride. However, this combined process is greatly affected by impurities in waste salt, evaporation equipment and cooling devices, etc., making it difficult to improve the purity of product salt, and the energy consumption is high in the waste salt resource utilization process, and the heat loss and cold utilization rate are not high. SUMMARY

[0004] The purpose of the present application is to provide an anti-fouling continuous freeze crystallization device and method to solve the problems raised in the background art.

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

[0006] The anti-fouling continuous freezing crystallization device and method 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, one end of the cyclone aerator is connected to the ozone generator, 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 is connected to the MVR evaporator, one end of the MVR evaporator flows into the A / B mixed salt dissolving tank, the end of the MVR evaporator away from the A / B mixed salt dissolving tank 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 dissolving tank, 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 fed into the A crystallization drying chamber and the B crystallization drying chamber.

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

[0008] Further, the gradient freezing crystallization chamber comprises a first-stage horizontal freezing crystallizer, a second-stage horizontal freezing crystallizer, a first-stage liquid pump and a second-stage liquid pump, the first-stage liquid pump is fixedly connected to the first-stage horizontal freezing crystallizer, the second-stage liquid pump is fixedly connected to the second-stage horizontal freezing crystallizer, one end of the first-stage horizontal freezing crystallizer is connected to the separation tank through the first-stage liquid pump, the end of the first-stage 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 first-stage horizontal freezing crystallizer is connected to the second-stage horizontal freezing crystallizer through the second-stage liquid pump, and the end of the second-stage horizontal freezing crystallizer away from the mixed salt concentration tank is connected to the A / B mixed salt dissolving tank; the mixed salt concentrated liquid is pumped into the first-stage horizontal freezing crystallizer to separate potassium chloride crystals and sodium chloride solution, the sodium chloride solution in the mixed salt concentration tank is pumped into the second-stage horizontal freezing crystallizer, and the ice blocks and ice residues are returned to the A / B mixed salt dissolving tank.

[0009] Further, the primary horizontal refrigeration crystallizer comprises a rotating module, a centrifugal spiral scraper, a pneumatic centrifugal nozzle, a material layer controller, a liquid outlet, a gas outlet, a compressor, a discharge port and a main cylinder, the rotating module is connected with the main cylinder, the rotating module rotates on the main cylinder, a plurality of centrifugal spiral scrapers are arranged on the rotating module, the centrifugal spiral scrapers are equal in spacing, a plurality of pneumatic centrifugal nozzles are arranged on the rotating module, the material layer controller is connected with the main cylinder, the material layer controller is fixed on the main cylinder, a through hole is arranged on the side of the main cylinder to connect the liquid outlet, one end of the liquid outlet penetrates through the main cylinder and the material layer controller, a through hole is arranged on the side of the main cylinder away from one end of the liquid outlet to connect the gas outlet, one end of the gas outlet penetrates through the main cylinder, the main cylinder is provided with the compressor away from the discharge port, the compressor is connected with the rotating module, the compressor is sequentially connected with an oil separator, an air-cooled condenser, a jacketed liquid storage tank, a filter and an expansion valve, and finally connected with the pneumatic centrifugal nozzle, one end of the rotating module close to the liquid outlet is provided with the discharge port, one end of the rotating module away from the discharge port is connected with a primary liquid pump, and one end of the liquid outlet away from the rotating module is connected with a salt mixed concentration tank.

[0010] Further, the rotating module comprises an air inlet jacket, a feed jacket and a main shaft, the main shaft is provided with the air inlet jacket, the air inlet jacket is fixedly connected with the compressor, the main shaft is provided with the feed jacket, the feed jacket is fixedly connected with the pneumatic centrifugal nozzle, the feed jacket is provided with a feed port connected with the primary liquid pump, and the main shaft is connected with the discharge port away from the primary liquid pump.

[0011] Further, the centrifugal spiral scraper comprises a scraper hub, a blade and a cone, the cone is provided with the scraper hub and the blade, and the cone is fixedly connected with the main shaft through the scraper hub; the cone is used for fixing the blade, and the blade is used for collecting the crystalline body to prevent the crystalline body from being scaled on the inner side of the main cylinder.

[0012] Further, the pneumatic centrifugal nozzle comprises an atomizing nozzle, a liquid inlet and an air inlet, one end of the liquid inlet is connected with the atomizing nozzle, the liquid inlet away from the atomizing nozzle is connected with the feed jacket, one end of the air inlet is connected with the atomizing nozzle, and the air inlet away from the atomizing nozzle is connected with the air inlet jacket; the atomizing nozzle uniformly sprays the pressurized solution into the inside of the main cylinder to accelerate the crystallization of potassium chloride.

[0013] Further, the secondary horizontal refrigeration crystallizer has the same structure as the primary horizontal refrigeration crystallizer, the feed jacket of the secondary horizontal refrigeration crystallizer is connected with the mixed salt concentration tank through a secondary liquid pump, and the discharge port of the secondary horizontal refrigeration crystallizer is connected with the A / B mixed salt dissolving pool; 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 A / B mixed salt water:

[0015] S1: The mixed salt water dissolved in the A / B mixed salt water dissolving pool is pretreated by using the micro-bubble enhanced ozonation technology to remove impurities: the impurities in the A / B mixed salt water affect the purity of the solution, and the micro-bubble enhanced ozonation technology is used to remove the impurities from the mixed salt water;

[0016] S2: The pretreated mixed salt water is put into the MVR evaporator to perform MVR evaporation concentration, the produced potassium chloride and sodium chloride concentrated solution is put into the separation tank, and the produced treatment effluent is returned to the A / B mixed salt dissolving pool: the MVR evaporator evaporates the water in the solution at high temperature and returns the water to the A / B mixed salt dissolving pool, and then the produced potassium chloride and sodium chloride concentrated solution is put into the separation tank;

[0017] S3: The mixed salt concentrated solution of potassium chloride and sodium chloride is pumped into the primary horizontal refrigeration crystallizer to perform crystallization concentration treatment, potassium chloride crystals and sodium chloride solution are obtained, and the potassium chloride crystals are dried to obtain potassium chloride product salt: the mixed salt concentrated solution of potassium chloride and sodium chloride is pumped from the separation tank into the feed jacket, the pumping speed is 0.5 L / min to 5 L / min, the mixed salt concentrated solution of potassium chloride and sodium chloride is uniformly sprayed into the inside of the main cylinder through the pneumatic centrifugal nozzle to crystallize, the crystallization temperature is 20 to 35℃, the centrifugal spiral scraper is arranged in the crystallizer, the stirring speed is 50 to 100 r / min, the potassium chloride crystals and the sodium chloride solution are separated out, the potassium chloride crystals are put into the A crystallization drying chamber to be dried to obtain the potassium chloride product salt, and the sodium chloride solution is put into the mixed salt concentration tank;

[0018] S4: The sodium chloride solution is pumped into the secondary horizontal refrigeration crystallizer to perform crystallization separation, the produced ice blocks and ice residues are returned to the A / B mixed salt dissolving pool, and the produced saturated sodium chloride solution is 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 refrigeration crystallizer, the pumping speed is 0.1 L / min to 2 L / min, the sodium chloride solution is uniformly sprayed into the inside of the main cylinder through the pneumatic centrifugal nozzle to crystallize, the crystallization temperature is -5 to 0℃, the centrifugal spiral scraper is arranged in the crystallizer, the stirring speed is 50 to 100 r / min, the ice blocks, the ice residues and the saturated sodium chloride solution are separated out, the ice blocks and the ice residues are transported to the A / B mixed salt dissolving pool, and the saturated sodium chloride solution is put into the B crystallization drying chamber to be dried at -20 to -40℃ to obtain the sodium chloride product salt.

[0019] Further, in the step S1, the micro-bubble reinforced ozonation technology adopts air source as the gas source of the ozone generator, the outlet of the ozone generator is connected with the cyclone aerator, the inlet pipe diameter of the cyclone aerator is DN20, the pipeline pressure grade is PN10, the cyclone aerator is arranged at the bottom of the A / B mixed salt water pretreatment pool, the micro-bubble 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.

[0020] Further, in the step S2, in the mother liquor circulation operation mode, the normal pressure evaporation temperature of the MVR evaporator is 75-95 ℃, the steam water amount is 80%-85%, and the treatment water generated by evaporation is returned to the A / B mixed salt dissolving pool, and the mixed salt concentrated liquid enters the separation tank.

[0021] Compared with the prior art, the beneficial effects achieved by the present application are: the cyclone aerator is used to realize controllable adjustment of the ozone bubble particle size, improve the utilization efficiency of ozone, and realize efficient removal of organic matter in wastewater; the gradient freezing crystallization chamber is composed of two-stage water pumps and two-stage horizontal freezing crystallizers, the crystallizer is provided with a screw scraper, which can effectively improve the heat exchange efficiency, and can avoid the blockage of the crystallizer by crystallized solids, and improve the solid-liquid separation efficiency; and the crystallization temperature range of the two-stage horizontal freezing crystallizer is gradiently distributed, this technology can effectively improve the heat exchange efficiency of cooling crystallization, reduce the cooling capacity loss, and realize continuous quality separation and purification of potassium chloride and sodium chloride. BRIEF DESCRIPTION OF DRAWINGS

[0022] The accompanying drawings are included to provide a further understanding of the present application, and constitute a part of the specification, illustrate the present application together with the embodiments thereof, and explain the present application, but do not constitute a limitation of the present application. In the drawings:

[0023] Fig. 1 is a schematic diagram of the overall structure of the present application;

[0024] Fig. 2 is a schematic diagram of the structure of the first-stage horizontal freezing crystallizer of the present application;

[0025] Fig. 3 is a schematic diagram of the structure of the centrifugal screw scraper of the present application;

[0026] Fig. 4 is a schematic diagram of the structure of the pneumatic centrifugal nozzle of the present application;

[0027] In the figure: 1, A / B mixed salt dissolving tank; 2, A / B mixed salt water pretreatment tank; 3, ozone generator; 4, cyclone aerator; 5, MVR evaporator; 6, separation tank; 7, gradient freeze crystallization chamber; 71, primary horizontal freeze crystallizer; 711, rotating module; 7111, air inlet jacket; 7112, feed jacket; 7113, main shaft; 712, centrifugal screw type 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, gas outlet; 717, compressor; 718, discharge port; 719, main cylinder; 72, secondary horizontal freeze crystallizer; 73, primary liquid pump; 74, secondary liquid pump; 8, mixed salt concentration tank. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0029] The present application provides technical solutions:

[0030] As shown in FIG. 1, taking potassium chloride and sodium chloride mixed salt as an example, a scale prevention continuous freeze crystallization device includes A / B mixed salt dissolving tank 1, A / B mixed salt water pretreatment tank 2, ozone generator 3, cyclone aerator 4, MVR evaporator 5, separation tank 6, gradient freeze crystallization chamber 7, mixed salt concentration tank 8, A crystallization drying chamber 9 and B crystallization drying chamber 10, the A / B mixed salt dissolving 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, the end of the cyclone aerator 4 away from the ozone generator 3 is connected to the A / B mixed salt water pretreatment tank 2, the A / B mixed salt water pretreatment tank 2 is connected to the MVR evaporator 5, one end of the MVR evaporator 5 is connected to the A / B mixed salt dissolving tank 1, the end of the MVR evaporator 5 away from the A / B mixed salt dissolving tank 1 is connected to the separation tank 6, the separation tank 6 is connected to the gradient freeze crystallization chamber 7, the gradient freeze crystallization chamber 7 is connected to the mixed salt concentration tank 8, the gradient freeze crystallization chamber 7 is connected to the A / B mixed salt dissolving tank 1, the mixed salt concentration tank 8 and the gradient freeze 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 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, the organic matter removal pretreatment of the mixed salt water is carried out by using the micro-bubble strengthened ozonation technology, the MVR evaporator 5 carries out the MVR evaporation concentration on the treated mixed salt water, the produced potassium chloride and sodium chloride concentrated solution enters the separation tank 6, the evaporation produced treatment effluent is refluxed 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 freeze crystallization chamber 7 to separate the potassium chloride crystal and the sodium chloride solution, the mixed salt concentrated tank 8 sends the separated potassium chloride crystal into the A crystallization drying chamber 9, and the potassium chloride product salt is obtained after freeze drying, the mixed salt concentrated tank 8 passes the separated sodium chloride solution into the gradient freeze crystallization chamber 7 to separate ice blocks, ice residues and a saturated sodium chloride solution, the produced ice blocks and ice residues are refluxed to the A / B mixed salt dissolving tank 1, and the saturated sodium chloride solution is sent into the B crystallization drying chamber 10.

[0032] As shown in Figure 1, the gradient freeze crystallization chamber 7 includes a first horizontal freeze crystallizer 71, a second horizontal freeze crystallizer 72, a first liquid pump 73 and a second liquid pump 74, the first liquid pump 73 is fixedly connected with the first horizontal freeze crystallizer 71, the second liquid pump 74 is fixedly connected with the second horizontal freeze crystallizer 72, one end of the first horizontal freeze crystallizer 71 is connected with the separation tank 6 through the first liquid pump 73, the end of the first horizontal freeze crystallizer 71 away from the separation tank 6 is connected with the mixed salt concentrated tank 8, the end of the mixed salt concentrated tank 8 away from the first horizontal freeze crystallizer 71 is connected with the second horizontal freeze crystallizer 72 through the second liquid pump 74, and the end of the second horizontal freeze crystallizer 72 away from the mixed salt concentrated tank 8 is connected with the A / B mixed salt dissolving tank 1.

[0033] The potassium chloride and sodium chloride concentrated solution of the separation tank 6 is pumped into the first horizontal freeze crystallizer 71 through the first liquid pump 73, the first horizontal freeze crystallizer 71 separates the potassium chloride crystal and the sodium chloride solution, the mixed salt concentrated tank 8 pumps the sodium chloride solution into the second horizontal freeze crystallizer 72 through the second liquid pump 74 to separate ice blocks, ice residues and a saturated sodium chloride solution, the multi-stage freeze crystallizer is connected in series, the heat exchange efficiency can be improved, the freeze crystallization temperature can be adjusted by gradient, the phased crystallization of components is realized, and the continuous quality separation crystallization of mixed salt is realized.

[0034] As shown in Figure 2, the primary horizontal refrigeration 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, a gas outlet 716, a compressor 717, a discharge port 718 and a main cylinder 719, the rotating module 711 is connected with the main cylinder 719, the rotating module 711 rotates on the main cylinder 719, a plurality of centrifugal spiral scrapers 712 are arranged on the rotating module 711, the centrifugal spiral scrapers 712 have equal spacing, a plurality of pneumatic centrifugal nozzles 713 are arranged on the rotating module 711, the material layer controller 714 is connected with the main cylinder 719, the material layer controller 714 is fixed on the main cylinder 719, a through hole is arranged on the side of the main cylinder 719 to connect 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 arranged on the side of the main cylinder 719 away from one end of the liquid outlet 715 to connect the gas outlet 716, one end of the gas outlet 716 passes through the main cylinder 719, the main cylinder 719 is away from the discharge port 718 and is provided with the compressor 717, the compressor 717 is connected with the rotating module 711, the compressor 717 is sequentially connected with an oil separator, an air-cooled condenser, a jacketed liquid storage tank, a filter and an expansion valve, and finally connected with the pneumatic centrifugal nozzle 713, the rotating module 711 is provided with the discharge port 718 near one end of the liquid outlet 715, the rotating module 711 is connected with the primary liquid pump 73 away from the discharge port 718, and one end of the liquid outlet 715 away from the rotating module 711 is connected with the mixed salt concentration tank 8.

[0035] The rotating module 711 passes the mixed salt water into the pneumatic centrifugal nozzle 713, passes the gas into the compressor 717, the compressor 717 is sequentially connected with an oil separator, an air-cooled condenser, a jacketed liquid storage tank, a filter and an expansion valve, and finally connected with the pneumatic centrifugal nozzle 713, pressurizes the pneumatic centrifugal nozzle 713, so that the mixed salt water is uniformly distributed in the jacket and forms a spray, which can quickly crystallize on the inner side wall of the main cylinder 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, the gas outlet 716 discharges the gas to maintain the air pressure, the centrifugal spiral scraper 712 collects the potassium chloride crystals by rotating the rotating module 711, avoids the scaling of the crystals on the inner side of the main cylinder 719, thereby effectively preventing the condenser from being blocked, improving the continuous crystallization effect, and the potassium chloride crystals are discharged from the main cylinder 719 through the discharge port 718.

[0036] As shown in Fig. 2, the rotating module 711 comprises an air inlet jacket 7111, a feed jacket 7112 and a main shaft 7113, the air inlet jacket 7111 is arranged on the main shaft 7113, and the air inlet jacket 7111 is fixedly connected with the compressor 717; the feed jacket 7112 is arranged on the main shaft 7113, and the feed jacket 7112 is fixedly connected with the pneumatic centrifugal nozzle 713; one end of the feed jacket 7112 is connected with the first-stage liquid pump 73; and the end of the main shaft 7113 away from the first-stage liquid pump 73 is connected with the discharge port 718.

[0037] The main shaft 7113 drives the centrifugal spiral scraper 712 to rotate; the feed jacket 7112 passes the mixed salt water into the pneumatic centrifugal nozzle 713; and the air inlet jacket 7111 passes the gas into the compressor 717 to pressurize, so that the mixed salt water is uniformly distributed in the jacket and forms a spray, and rapid crystallization can be formed on the inner side wall of the main cylinder 719.

[0038] As shown in Fig. 3, the centrifugal spiral scraper 712 according to claim 4 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 scraper hub 7121 is fixedly connected with 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 crystallization on the inner side wall of the main cylinder 719.

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

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

[0042] As shown in Fig. 1 and Fig. 2, the second-stage horizontal refrigeration crystallizer 72 has the same structure as the first-stage horizontal refrigeration crystallizer 71, the feed jacket 7112 of the second-stage horizontal refrigeration crystallizer 72 is connected with the mixed salt concentration tank 8 through the second-stage liquid pump 74, and the discharge port 718 of the second-stage horizontal refrigeration crystallizer 72 is connected with the A / B mixed salt dissolving pool 1.

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

[0044] As shown in FIG. 1, the crystallization method includes the following steps in the process of treating mixed salt water of potassium chloride and sodium chloride:

[0045] S1: The mixed salt water dissolved in the A / B mixed salt water pretreatment pool 2 is pretreated by using the micro-bubble enhanced ozonation technology to remove organic impurities: the impurities in the A / B mixed salt water affect the purity of the solution, and the micro-bubble enhanced ozonation technology is used to remove impurities from the mixed salt water;

[0046] S2: The pretreated mixed salt water is put into the MVR evaporator 5 for MVR evaporation concentration, and the produced potassium chloride and sodium chloride concentrate is put into the separation tank 6, and the evaporation produced treatment water is returned to the A / B mixed salt dissolution pool 1: the MVR evaporator evaporates the water in the solution by high temperature, and returns it to the A / B mixed salt dissolution pool 1, and then the produced potassium chloride and sodium chloride concentrate is put into the separation tank 6;

[0047] S3: The mixed salt concentrate of potassium chloride and sodium chloride is pumped into the primary horizontal refrigeration crystallizer 71 for crystallization concentration treatment, and potassium chloride crystals and sodium chloride solution are obtained, and potassium chloride product salt is obtained after freeze-drying of potassium chloride crystals: the mixed salt concentrate of potassium chloride and sodium chloride is pumped into the feed jacket 7112 from the separation tank 6, and the pump speed is 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 cylinder 719 through the pneumatic centrifugal nozzle 713 to crystallize, the crystallization temperature is 20-35℃, the crystallizer is provided with a centrifugal spiral scraper 712 inside, the stirring speed is 50-100 r / min, the potassium chloride crystals and the sodium chloride solution are separated out, the potassium chloride crystals are put into the A crystallization drying chamber 9 for freeze-drying to obtain potassium chloride product salt, and the sodium chloride solution is put into the mixed salt concentration tank 8;

[0048] S4: Pumping the sodium chloride solution into the secondary horizontal refrigeration crystallizer 72 for crystallization separation, the generated ice blocks and ice residues are backflowed to the A / B mixed salt dissolving tank 1, and the generated sodium chloride saturated solution is dried by crystallization 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 refrigeration crystallizer 72, the pumping speed is 0.1 L / min-2 L / min, the sodium chloride solution is uniformly sprayed into the inside of the main cylinder 719 for crystallization through the pneumatic centrifugal nozzle 713, the crystallization temperature is-5-0 DEG C, the inside of the crystallizer is provided with a centrifugal spiral scraper 712, and the stirring speed is 50-100 r / min, the ice blocks, ice residues and sodium chloride saturated solution are separated, the ice blocks and ice residues are transported to the A / B mixed salt dissolving tank 1, the sodium chloride saturated solution is introduced into the B crystallization drying chamber 10, and the sodium chloride product salt is obtained after being frozen and dried at-20--40 DEG C.

[0049] As shown in Figure 1, in the step S1, the micro-bubble reinforced ozonation technology adopts air as the gas source of the ozone generator 3, the outlet of the ozone generator 3 is connected with the cyclone aerator 4, the inlet pipe diameter of the cyclone aerator 4 is DN20, the pipeline pressure grade is PN10, the cyclone aerator 4 is arranged at the bottom of the A / B mixed salt water pretreatment tank 2, the micro-bubble particle size is adjusted to 0.1-0.6 mu m, the bubble density is 0.1-0.6 g / cm3, and the ozone dosage is 8-15 mg / m3.

[0050] The cyclone aerator 4 is adopted to realize controllable adjustment of the ozone bubble particle size generated by the ozone generator 3, the utilization efficiency of ozone is improved, and the organic matter in the wastewater is efficiently removed.

[0051] As shown in Figure 1, in the step S2, in the mother liquor circulation operation mode, the normal pressure evaporation temperature of the MVR evaporator 5 is 75-95 DEG C, the steam water amount is 80%-85%, the treatment effluent generated by evaporation is backflowed to the A / B mixed salt dissolving tank 1, and the mixed salt concentrated liquid enters the separation tank 6.

[0052] The MVR evaporator 5 is used for MVR evaporation concentration treatment of the mixed salt water, the treatment effluent generated by evaporation is backflowed to the A / B mixed salt dissolving tank 1, and the generated mixed salt concentrated liquid enters the separation tank 6.

[0053] The working principle of the application is as follows: the micro-bubble reinforced ozonation technology is used for efficient impurity removal of organic matter in the potassium chloride and sodium chloride mixed salt water, and the purity of the mixed salt water is improved; based on the centrifugal spiral scraper discharge design of the horizontal refrigeration crystallizer, the gradient refrigeration crystallization purpose is realized under the arrangement advantages of high heat exchange efficiency of the self-developed two-stage refrigeration crystallization, on the one hand, the utilization efficiency of cold energy is improved, and the fouling and blockage of the refrigeration cylinder are avoided; on the other hand, continuous fractional crystallization purification of the potassium chloride and sodium chloride mixed salt is realized.

[0054] It should be noted that the relationship terms, such as first and second, and the like, are used only to differentiate one entity or action from another, and do not necessarily require or imply any actual such relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0055] Finally, it should be noted that the above-described embodiments are merely possible implementations of the present application, but not to be taken to limit the present application. Although the present application has been described in detail with reference to the foregoing embodiments, the technical solutions recorded in the foregoing embodiments can still be modified by those skilled in the art, or some technical features thereof can be replaced by equivalent replacements. Any modifications, equivalent replacements, improvements, and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An anti-fouling continuous freeze crystallization apparatus, characterized by: The device comprises an A / B mixed salt dissolving 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 freeze 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 dissolving 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), the end of the cyclone aerator (4) away from the ozone generator (3) is connected to the A / B mixed salt water pretreatment tank (2), the A / B mixed salt water pretreatment tank (2) is connected to the MVR evaporator (5), one end of the MVR evaporator (5) returns to the A / B mixed salt dissolving tank (1), the end of the MVR evaporator (5) away from the A / B mixed salt dissolving tank (1) flows into the separation tank (6), the separation tank (6) is connected to the gradient freeze crystallization chamber (7), the gradient freeze crystallization chamber (7) is connected to the mixed salt concentration tank (8), the gradient freeze crystallization chamber (7) is connected to the A / B mixed salt dissolving tank (1), the mixed salt concentration tank (8) and the gradient freeze crystallization chamber (7) are respectively connected to the A crystallization drying chamber (9) and the B crystallization drying chamber (10); The gradient freeze crystallization chamber (7) comprises a first horizontal freeze crystallizer (71), a second horizontal freeze crystallizer (72), a first liquid pump (73) and a second liquid pump (74). The primary horizontal refrigeration crystallizer (71) comprises a rotating module (711), centrifugal spiral scrapers (712), pneumatic centrifugal nozzles (713), a material layer controller (714), a liquid outlet (715), a gas outlet (716), a compressor (717), a discharge port (718) and a main cylinder (719), the rotating module (711) is connected with the main cylinder (719), the rotating module (711) rotates on the main cylinder (719), a plurality of centrifugal spiral scrapers (712) are arranged on the rotating module (711), the centrifugal spiral scrapers (712) are equal in spacing, a plurality of pneumatic centrifugal nozzles (713) are arranged on the rotating module (711), the material layer controller (714) is connected with the main cylinder (719), the material layer controller (714) is fixed on the main cylinder (719), a through hole is arranged on the side of the main cylinder (719) to connect the liquid outlet (715), one end of the liquid outlet (715) penetrates through the main cylinder (719) and the material layer controller (714), a through hole is arranged on the side of the main cylinder (719) away from one end of the liquid outlet (715) to connect the gas outlet (716), one end of the gas outlet (716) penetrates through the main cylinder (719), the main cylinder (719) is provided with the compressor (717) away from the discharge port (718), the compressor (717) is connected with the rotating module (711), the compressor (717) is sequentially connected with an oil separator, an air-cooled condenser, a jacketed liquid storage tank, a filter and an expansion valve, and finally connected with the pneumatic centrifugal nozzle (713), the rotating module (711) is provided with the discharge port (718) close to one end of the liquid outlet (715), the rotating module (711) is connected with the primary liquid pump (73) away from one end of the discharge port (718), and one end of the liquid outlet (715) away from the rotating module (711) is connected with the mixed salt concentration tank (8).

2. An anti-fouling continuous freeze crystallization apparatus as claimed in claim 1, wherein: The primary liquid pump (73) is fixedly connected with the primary horizontal refrigeration crystallizer (71), the secondary liquid pump (74) is fixedly connected with the secondary horizontal refrigeration crystallizer (72), one end of the primary horizontal refrigeration crystallizer (71) is connected with the separation tank (6) through the primary liquid pump (73), the primary horizontal refrigeration crystallizer (71) is connected with the mixed salt concentration tank (8) away from the separation tank (6), one end of the mixed salt concentration tank (8) away from the primary horizontal refrigeration crystallizer (71) is connected with the secondary horizontal refrigeration crystallizer (72) through the secondary liquid pump (74), and one end of the secondary horizontal refrigeration crystallizer (72) away from the mixed salt concentration tank (8) is connected with the A / B mixed salt dissolving tank (1).

3. An anti-fouling continuous freeze crystallization apparatus as claimed in claim 2, wherein: The rotating module (711) comprises an air inlet jacket (7111), a feed jacket (7112) and a main shaft (7113), the air inlet jacket (7111) is arranged on the main shaft (7113), and the air inlet jacket (7111) is fixedly connected with the compressor (717); the feed jacket (7112) is arranged on the main shaft (7113), and the feed jacket (7112) is fixedly connected with the pneumatic centrifugal nozzle (713); the feed jacket (7112) is provided with a feed port connected with a first-stage liquid pump (73); and the main shaft (7113) is connected with a discharge port (718) at an end away from the first-stage liquid pump (73).

4. An anti-fouling continuous freeze crystallization apparatus as claimed in claim 3, wherein: 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 with the main shaft (7113) through the scraper hub (7121).

5. An anti-fouling continuous freeze crystallization apparatus as claimed in claim 4, wherein: 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 with the atomizing nozzle (7131), one end of the liquid inlet (7132) away from the atomizing nozzle (7131) is connected with the feed jacket (7112), one end of the air inlet (7133) is connected with the atomizing nozzle (7131), and one end of the air inlet (7133) away from the atomizing nozzle (7131) is connected with the air inlet jacket (7111).

6. An anti-fouling continuous freeze crystallization apparatus as claimed in claim 5, wherein: The second-stage horizontal refrigeration crystallizer (72) has the same structure as the first-stage horizontal refrigeration crystallizer (71), the feed jacket (7112) of the second-stage horizontal refrigeration crystallizer (72) is connected with a mixed salt concentration tank (8) through a second-stage liquid pump (74), and the discharge port (718) of the second-stage horizontal refrigeration crystallizer (72) is connected with an A / B mixed salt dissolving pool (1).

7. A crystallization method of a scale prevention continuous freeze crystallization apparatus according to claim 6, characterized in that: The crystallization method comprises the following steps in the process of treating mixed salt water of potassium chloride and sodium chloride: S1: organic matter is removed and pretreated from mixed salt water dissolved in a mixed salt water pretreatment pool (2) by using a micro-bubble enhanced ozonation technology; S2: the pretreated mixed salt water is put into an MVR evaporator (5) to perform MVR evaporation and concentration, the produced concentrated liquid of potassium chloride and sodium chloride is put into a separation tank (6), and the produced treated effluent is returned to the A / B mixed salt dissolving pool (1). S3: Pump the mixed salt concentrated solution of potassium chloride and sodium chloride into a first horizontal refrigeration crystallizer (71) for crystallization concentration treatment, to obtain potassium chloride crystals and a sodium chloride solution, and the potassium chloride crystals are freeze-dried to obtain potassium chloride product salt, the mixed salt concentrated solution of potassium chloride and sodium chloride is pumped from the separation tank (6) into the feed jacket (7112), the pump speed is 0.5 L / min-5 L / min, the mixed salt concentrated solution of potassium chloride and sodium chloride is uniformly sprayed into the inside of the main cylinder (719) for crystallization by the pneumatic centrifugal nozzle (713), the crystallization temperature is 20-35℃, the crystallizer is internally provided with a centrifugal spiral scraper (712), the stirring speed is 50-100 r / min, the potassium chloride crystals and the sodium chloride solution are separated, the potassium chloride crystals are introduced into the A crystallization drying chamber for freeze-drying to obtain the potassium chloride product salt, and the sodium chloride solution is introduced into the mixed salt concentration tank; S4: Pump the sodium chloride solution into a second horizontal refrigeration crystallizer (72) for crystallization separation, the ice blocks and ice residues generated are returned to the A / B mixed salt dissolution tank (1), the saturated sodium chloride solution generated is dried by crystallization to obtain product salt, the sodium chloride solution is pumped from the mixed salt concentration tank (8) into the feed jacket (7112) of the second horizontal refrigeration crystallizer (72), the pump speed is 0.1 L / min-2 L / min, the sodium chloride solution is uniformly sprayed into the inside of the main cylinder (719) for crystallization by the pneumatic centrifugal nozzle (713), the crystallization temperature is -5-0℃, the crystallizer is internally provided with a centrifugal spiral scraper (712), the stirring speed is 50-100 r / min, the ice blocks, ice residues and saturated sodium chloride solution are separated, the ice blocks and ice residues are transported to the A / B mixed salt dissolution tank, and the saturated sodium chloride solution is introduced into the B crystallization drying chamber, and the sodium chloride product salt is obtained after freeze-drying at -20--40℃.

8. A crystallization method of a scale prevention continuous freeze crystallization apparatus according to claim 7, characterized by: In the step S1, the air source is used as the gas source of the ozone generator (3) in the microbubble enhanced ozonation technology, the outlet of the ozone generator (3) is connected with the cyclone aerator (4), the gas inlet pipe diameter of the cyclone aerator (4) is DN20, the pipeline pressure grade is PN10, the cyclone aerator (4) is arranged 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, in the mother liquor circulation operation mode, the normal pressure evaporation temperature of the MVR evaporator (5) is 75-95℃, the steam water amount is 80%-85%, the treatment effluent generated by evaporation is returned to the A / B mixed salt dissolution tank (1), and the mixed salt concentrated solution enters the separation tank (6).

9. The method of claim 7, wherein the apparatus is a continuous freeze crystallization apparatus. The application of resourceful treatment of mixed salt wastewater containing sodium chloride and potassium chloride generated in the processes of antibiotic production and fly ash water washing.

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