High-performance progressive freeze concentration experimental equipment capable of realizing continuous multi-stage concentration

Abstract

The invention relates to high-performance progressive freezing concentration experimental equipment capable of realizing continuous multi-stage concentration. The high-performance progressive freezing concentration experimental equipment comprises concentration tanks I, II and III, a refrigerating system, a low-temperature secondary refrigerant tank, a normal-temperature secondary refrigerant tank and an intelligent operation control system, the concentration tank I, the concentration tank II and the concentration tank III are flat cuboid progressive freezing concentration tanks with stainless steel sandwich structures, the volume of the tank I is 10-500L, the volume of the tank II is 50%-100% of that of the tank I, the volume of the tank III is 50%-100% of that of the tank II, and the tanks are arranged in sequence. And the intelligent operation control unit is associated with the mechanisms to form functions such as operation instruction and information feedback automatic operation, remote control and the like. According to the equipment disclosed by the invention, through a multi-tank series connection sequence, one-stage to multi-stage continuous freeze concentration of feed liquid is realized in an interactive switching operation mode, and the bottleneck problems of intermittent operation, low concentration efficiency and the like of a traditional progressive freeze concentration experimental device are solved through a unique tank body structure and an ingenious series combination technical scheme; the operation energy consumption is obviously reduced; the concentration efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of environment-friendly low-temperature concentration intelligent equipment, and relates to a high-performance progressive freezing concentration experimental equipment capable of continuous multi-stage concentration. Background Art

[0002] Freeze concentration is a high-tech technology commonly used in the food, health products, biopharmaceuticals and environmental protection industries to operate below the freezing point of aqueous solutions and achieve liquid material concentration. Compared with conventional concentration technologies such as evaporation concentration and vacuum concentration, it has great advantages in effectively protecting and recovering the nutrients, bioactive ingredients, natural aromatic flavor substances and natural pigments of heat-sensitive liquid materials. According to the different ways of ice nucleus formation and ice crystal removal in aqueous solutions, freeze concentration can be divided into two major technical systems: suspension and progressive. Suspension freeze concentration adopts the operation mode of multiple ice crystal formation, growth and regular removal. It was first studied in Western developed countries. Especially after solving the efficient ice crystal removal technology, the concentration efficiency has been greatly improved, and the equipment performance has become mature. It has been commercialized in the fields of food, biopharmaceuticals, environmental wastewater treatment, etc. for more than 40 years, but it has defects such as complex equipment structure, high manufacturing cost and difficulty in popularization and promotion. The operating principle of progressive freeze concentration is different from that of suspension freeze concentration. The aqueous solution grows from ice crystals to a single thick ice layer on the cold wall surface of the concentration device. After the ice layer is removed, the aqueous solution is concentrated. Therefore, the significant advantage of progressive freeze concentration is that it does not require complex deicing equipment, the deicing operation is relatively simple, and the equipment cost is lower. It has now become another important development direction for freeze concentration equipment. At present, progressive freeze concentration has evolved into concentration devices based on different operating methods, such as round tanks, circulation pipes, falling film sheets and rotary drums.

[0003] However, there are some technical bottlenecks in the traditional progressive freeze concentration equipment that have not been solved, which significantly affect the concentration efficiency and production operation efficiency. These technical bottlenecks include: (1) Progressive freeze concentration uses a single ice crystal to grow into a thick ice layer, thereby reducing the proportion of liquid water in the solution to achieve an increase in the concentration of the feed liquid. Since the thermal conductivity of solid ice is only about 1 / 4 of that of liquid water, the thicker the ice layer is during the freeze concentration process, the more difficult it will be for the aqueous solution to transfer heat to the cold wall through the ice layer. Studies have shown that within the commonly used freeze concentration temperature range of -10℃ to -40℃, when a 2-3cm thick ice layer is formed on the cold wall of the concentration device, the thickening rate of the ice layer on the solution side will begin to be affected; when a ≥10cm thick ice layer is formed on the cold wall of the concentration device, the thermal resistance of the ice layer will become a limiting factor for heat transfer in the concentration tank. It takes at least 3 hours for the ice layer on the solution side to thicken by 1cm, which seriously affects the freeze concentration process. (2) In order to save manufacturing costs, traditional progressive freeze concentration tanks often adopt a circular tank design. However, when the capacity of the circular tank increases to a certain extent, under the condition of appropriate tank height, the radius of the concentration tank can easily exceed 10cm (for example, when the capacity of the circular concentration tank reaches 150L, ​​its radius will exceed 25cm). This means that even if the conventional 2-3 times concentration ratio is achieved, the thickness of the ice layer on the inner wall of the circular concentration tank will seriously affect the freeze concentration process, not only consuming more operating energy of the equipment, but also the concentration efficiency is not ideal. (3) The current progressive freeze concentration equipment is basically designed as a single tank intermittent operation mode. After each stage of freeze concentration is completed, the machine must be shut down and thawed and de-iced before the next stage of freeze concentration can be carried out. This non-continuous operation mode also seriously affects production efficiency. For example, the disclosed progressive freezing concentration device technical solutions such as "CN108176074A A progressive freezing concentration device and freezing concentration method with a double-sandwich structure", "CN210964869U-A progressive freezing concentration device with a double-sandwich structure", "CN 208340156 U Tubular circulation freezing concentration device containing a heat transfer buffer layer", and "CN209219223 U Progressive freezing concentration device for liquid food" all belong to single circular tank or circular tube intermittent freezing concentration test devices with limited operating efficiency; and the ice layer formed on the inner wall of the circular tank or circular tube concentrator is a cylindrical ice ring centered on the longitudinal axis of the circular tank or circular tube. These cylindrical ice rings are irregular fan-shaped after breaking and are not easy to peel off from the tank, increasing the labor intensity of de-icing.For example, the patents disclosed, such as "CN 108477441 A A device and method for preparing concentrated juice by continuous freezing" and "CN 202281416 U A micro device for rapidly and continuously preparing cooling and freezing liquids", which claim to be capable of continuous multi-stage concentration, are all progressive concentration devices containing only a single freezing concentration tank, which cannot truly and effectively realize continuous multi-stage progressive freezing concentration operations, let alone rapid thawing and deicing; the progressive freezing concentration device capable of continuous multi-stage concentration described in the disclosed "CN113769432A A fully automatic freezing concentration device and a process for preparing concentrated liquids" contains two freezing concentration barrels, which can realize continuous freezing concentration from the first stage to the second stage in a certain sense, but cannot realize rapid thawing and deicing, and the actual operation efficiency is not high. Therefore, in the field of progressive freezing concentration equipment, only by solving the above-mentioned technical bottleneck problems can a progressive freezing concentration equipment with excellent performance be designed and manufactured. Summary of the invention

[0004] Based on this, the purpose of the present invention is to use a flat rectangular-shaped freezing concentration tank to provide a high-performance progressive freezing concentration experimental equipment that can perform continuous multi-stage concentration by connecting multiple tanks in series, thereby achieving higher concentration efficiency, lower operating energy consumption, and continuous freezing concentration operation from one stage to multiple stages compared to conventional circular concentration tanks and inefficient single-tank intermittent progressive freezing concentration equipment.

[0005] The above technical objectives of the present invention are achieved through the following technical solutions:

[0006] A high-performance progressive freezing concentration experimental equipment capable of continuous multi-stage concentration includes No. I, No. II and No. III stainless steel sandwich flat rectangular progressive freezing concentration tanks, low-temperature coolant tanks, room-temperature coolant tanks, a refrigeration system, an intelligent operation control system and other core structures.

[0007] The No. I, No. II and No. III stainless steel sandwich flat rectangular progressive freezing concentration tanks all include matching temperature recording probes, tank covers, LED lighting, real-time camera devices and stirring devices.

[0008] The No. I, No. II and No. III stainless steel sandwich flat rectangular progressive freezing concentration tanks, wherein the volume of No. I concentration tank is between 10L and 500L; when the volume model of No. I concentration tank is determined, the volume of No. II concentration tank is 50% to 100% of that of No. I concentration tank, and the volume of No. III concentration tank is 50% to 100% of that of No. II concentration tank.

[0009] The inner cavity middle side of the flat rectangular progressive freezing concentration tank of the stainless steel sandwich structure of the No. I, No. II and No. III concentration tanks is composed of two stainless steel flat plates, which are combined with a stainless steel semi-cylindrical shell at each end of the tank body. The diameter and height of the stainless steel semi-cylindrical shell at both ends are equal to the spacing and height of the two stainless steel flat plates. The bottom is a stainless steel concave component with the same shape and size as the cross-section of the tank body, which is welded together. Taking into account the maximum concentration efficiency and the convenience of operation, the size range of the two stainless steel flat plates in the middle of the tank body is: 10cm to 150cm long, 15cm to 120cm high, and the distance between the two plates is 8cm to 30cm. The outer layer of the No. I, No. II and No. III concentration tanks is a stainless steel outer interlayer. According to the heat transfer requirements of the concentration tanks of different sizes, the thickness of the refrigerant in the outer interlayer ranges from 1cm to 10cm.

[0010] The bottom of the outer interlayer of the No. I, No. II and No. III concentration tanks each contains two refrigerant inlets, and the upper part of the outer interlayer contains two refrigerant outlets; the two refrigerant inlets are respectively installed at the obliquely symmetrical tangent positions of the junction part of the semi-cylindrical outer interlayer at both ends of the freezing concentration tank body and the bottom of the rectangular outer interlayer, and the two refrigerant outlets are respectively installed at the obliquely symmetrical tangent positions of the junction part of the semi-cylindrical outer interlayer at both ends of the freezing concentration tank body and the upper end of the rectangular outer interlayer.

[0011] One to two temperature recording probes are installed in the outer interlayer of the No. I, No. II and No. III concentration tanks; two temperature recording probes are installed inside the tank, one of which is installed close to the middle of the inner wall of one of the two semi-cylinders to record the temperature change process of the solution close to the inner wall of the tank, and the other is installed at the bottom of the tank close to the discharge port to record the temperature change process of the solution in the center of the tank.

[0012] The shape of the tank covers of the No. I, No. II and No. III concentration tanks is consistent with the size of the tank edge at the upper end of the freezing concentration tank body, and is fixed and sealed by a sealing ring and a buckle; an LED lighting lamp and a real-time camera device are installed on the top of the tank cover, which can observe, take pictures or record the freezing concentration process and ice ring growth process in real time.

[0013] The No. I, No. II and No. III concentration tanks are installed with 1 to 3 stirring devices according to their respective volume types, wherein a 2L to 50L small tank is installed with 1 stirring device, the stirring motor is installed at the geometric center position on the tank cover, the upper end of the stirring paddle is connected to the stirring motor shaft through a movable clamp, and the lower end of the stirring paddle is connected to the center of the movable disc at the bottom of the tank, and the stirring paddle can be removed when necessary; 50L to 150L medium-sized tanks are installed with 2 stirring devices, which are respectively installed in the middle of the 1st and 3rd dividing lines of the tank cover's transverse center axis divided into four equal parts, and the stirring motor and the stirring paddle are installed in the same manner as described above, but the directions of the two stirring motors are opposite; 150L to 500L large tanks are installed with 3 stirring devices, which are respectively installed in the middle of the 1st, 3rd and 5th dividing lines of the tank cover's transverse center axis divided into six equal parts, and the stirring motor and the stirring paddle are installed in the same manner as described above, but the directions of the three stirring motors are opposite in sequence.

[0014] The low-temperature coolant tank forms a low-temperature coolant circulation with the refrigeration system, heat exchanger, etc. through a circulation pump, valves and pipelines, and can continuously adjust the required temperature of the coolant in the low-temperature coolant tank; the low-temperature coolant tank is simultaneously connected to the two coolant inlets and two coolant outlets of the outer interlayer of the No. I, No. II and No. III concentrators through a circulation pump, valves and pipelines to form independent low-temperature coolant circulations, respectively, to achieve freeze concentration of the liquid in the corresponding concentrators I, II and III. In particular, when only one refrigeration compressor is installed in the refrigeration system, only one of the No. I, No. II and No. III concentrators can be freeze concentrated, and freeze concentration cannot be performed synchronously; when three refrigeration compressors are installed in the refrigeration system and three heat exchangers are respectively connected to the No. I, No. II and No. III concentrators to form independent low-temperature coolant circulations, the No. I, No. II and No. III concentrators can be freeze concentrated synchronously, achieving a more efficient continuous freeze concentration operation.

[0015] The normal temperature refrigerant tank is loaded with normal temperature refrigerant, and only forms independent normal temperature refrigerant circulation with the outer interlayer of concentrating tanks No. I, II and III respectively through circulating pumps, pipelines and valves; the normal temperature refrigerant tank itself is equipped with a heater and a circulating pump, which can adjust the loaded refrigerant to a normal temperature state above 0°C. When the freeze concentration of the corresponding concentrating tanks No. I, II and III is completed, the normal temperature refrigerant circulation can be used to quickly thaw the ice layer on the joint surface of the inner wall of the corresponding concentrating tank and the ice ring, so as to facilitate the detachment and de-icing of the ice ring.

[0016] The No. I, No. II and No. III concentration tanks are all flat rectangular progressive freezing concentration tanks of different volume models with a volume ranging from 2L to 500L. The half-width dimension of the rectangular section in the middle of the concentration tank and the radius of the semi-cylindrical semi-circular section at both ends are both in the range of 4cm to 15cm. This tank cavity structure can limit the thickest ice layer formed on each single cold wall surface in the tank to ≤4cm to 15cm. Furthermore, under the same concentration ratio, the thickness of the ice layer on the flat rectangular progressive freezing concentration tank will be much smaller than the 6.5cm to 32.5cm ice layer thickness of the circular progressive freezing concentration tank of the same volume. The thinner ice layer will significantly improve the heat transfer efficiency between the inner wall of the concentration tank and the liquid in the center of the tank, thereby significantly shortening the freezing concentration time, improving the concentration efficiency, and reducing the energy consumption of equipment operation.

[0017] The intelligent operation control system is composed of an operation panel, a data processing and automatic control module, a recording storage, and an electrical control element; the electrical control element is respectively connected to the refrigeration system, a low-temperature coolant tank, a normal-temperature coolant tank, a concentration tank No. I, a concentration tank No. II, and a concentration tank No. III and their corresponding supporting circulation pumps, temperature probes, stirring devices, LED lighting, and real-time camera devices, so as to realize the setting and modification of the freezing concentration operation parameters, automatic operation of the whole machine, remote monitoring, and real-time display, storage, and export of operation parameters, data, and image materials.

[0018] The No. I, No. II and No. III concentration tanks are used in combination with a low-temperature coolant tank, a normal-temperature coolant tank, a refrigeration system and an operation control system. The No. I, No. II and No. III concentration tanks can independently run a freeze concentration or thawing program, and through the sequential and interactive switching operation modes of the No. I, No. II and No. III concentration tanks, one to multiple stages of continuous freeze concentration of the feed liquid can be achieved until the feed liquid is concentrated to a target concentration or a maximum ultimate concentration of 50% (w / w).

[0019] The No. I, No. II and No. III concentration tanks can respectively perform independent freeze concentration operations on their respective feed liquids and thaw and de-ice operations on the ice rings after the freeze concentration is completed; further, the No. I, No. II and No. III concentration tanks can, in order from large to small in volume, start from the initial feed liquid, and then successively complete the first-level, second-level and third-level freeze concentration from No. I to No. II and then to No. III concentration tanks; if necessary, a new round of freeze concentration from the fourth level to the fifth level and then to the sixth level can be completed successively from the third-level frozen concentrate, and then from No. I to No. II and then to No. III concentration tanks, until the target concentration or the ultimate concentration of up to 50% (w / w) is reached.

[0020] In the freeze concentration stage, the operation panel can independently set the freeze concentration temperature range and corresponding operation time for each of the No. I, No. II and No. III concentration tanks. Furthermore, the descending temperature range and corresponding operation time for freeze concentration of the No. I, No. II and No. III concentration tanks can be independently set in a gradient segmented cooling sequence of one, two, three, four and five stages; further, the intelligent operation control system can automatically perform freeze concentration in sequence for the first, second, third, fourth to fifth stage process parameters set for each of the No. I, No. II and No. III concentration tanks.

[0021] In the thawing stage after the freeze concentration is completed, the operation panel can independently set the ice ring thawing temperature and thawing time for each of the concentration tanks No. I, No. II and No. III. Further, when any of the concentration tanks No. I, No. II and No. III after the freeze concentration is completed needs to be thawed, the thawing procedure can be executed separately, and the intelligent operation control system can start the heater and circulation pump of the normal temperature coolant tank, and simultaneously start the normal temperature coolant circulation between the outer interlayer of any of the concentration tanks No. I, No. II and No. III and the normal temperature coolant tank to implement the thawing of the ice ring.

[0022] Compared with the traditional single-tank freeze concentration equipment, the concentration efficiency and production efficiency of the equipment are significantly improved. When the equipment uses the No. I, No. II and No. III concentration tanks to perform one-stage to multi-stage freeze concentration on the relevant liquid, the concentrate of the previous stage can be immediately transported to the next concentration tank, seamlessly docked and perform the next stage of freeze concentration. The concentration process is continuous and the concentration efficiency is improved; further, after the freeze concentration of any of the No. I, No. II and No. III concentration tanks of the equipment is completed, the independent normal temperature refrigerant circulation can be synchronously switched to perform rapid ice ring thawing and complete the deicing operation, which can significantly improve the production efficiency.

[0023] The equipment performs one-stage or multi-stage continuous freeze concentration of the relevant liquid, while saving the energy consumption of the equipment operation and improving the concentration efficiency and production efficiency, which is achieved through the following steps:

[0024] Operation step 1: First, complete the first-stage freeze concentration of the initial liquid in the No. I concentration tank and the de-icing operation after the freeze concentration is completed: ① Turn on the power of the equipment and turn on the intelligent operation control system; transport the initial liquid to the No. I concentration tank to reach the corresponding volume. ② Referring to the freezing point and supercooling point of the initial liquid, set the first to fifth freeze concentration temperature range of the No. I concentration tank and the operating time parameters of each section on the operation panel, start the freeze concentration of the No. I concentration tank, and set the stirring time and start stirring at the same time. Accelerate the heat transfer and cooling rate of the liquid and eliminate the concentration polarization of the solute on the surface of the ice layer. ③ Open the video to observe the thickening of the ice layer. When the No. I concentration tank automatically completes the first to fifth continuous freeze concentration procedures, or the ice layer in the No. I concentration tank is close to the stirring blade, stop stirring, open the tank cover and remove the stirring blade, and take a small amount of concentrated liquid from the No. I concentration tank to determine its concentration. ④ When the concentrated liquid does not reach the expected concentration, all the first-stage frozen concentrate is transported to the No. II frozen concentration tank, and the first-stage freeze concentration is terminated at the same time; when the expected concentration has been reached, the first-stage freeze concentration is terminated and the second-stage freeze concentration is no longer performed. ⑤ At the same time, set the thawing temperature and thawing time of the No. I concentration tank, start the heater and circulation pump of the normal temperature refrigerant tank and the circulation of the normal temperature refrigerant in the outer interlayer of the No. I concentration tank, and after the thawing of the ice ring in the No. I concentration tank is completed, the outer ring of the ice ring is separated from the inner wall of the No. I concentration tank. ⑥ Take out the ice ring in the No. I concentration tank, break it, and use the matching centrifuge to recover the entrained liquid in the ice cubes. The recovered entrained liquid can be added to the II concentration tank for mixing, and the remaining first-level white ice can be discarded. ⑦ Furthermore, before the first-level freeze concentration reaches the expected target concentration and ends the operation of the whole machine, the first-level freeze concentration process data can be exported using a U disk, the equipment can be cleaned, and the power can be turned off. At this point, the first-level freeze concentration of the initial feed liquid in the No. I concentration tank and the deicing operation in the No. I concentration tank are all completed.

[0025] Operation step 2: When the first-stage frozen concentrate does not reach the target concentration and needs to be subjected to the second-stage frozen concentration, the second-stage frozen concentration of the first-stage frozen concentrate in the No. II concentration tank is immediately started after receiving the first-stage frozen concentrate. After the freeze concentration is completed, the ice ring thawing and deicing operation are completed. ① Referring to the center temperature in the tank when the first-stage frozen concentration is completed, set the first to fifth stage frozen concentration temperature range and the operating time parameters of each stage of the No. II concentration tank on the operation panel, start the freeze concentration of the No. II concentration tank, and set the stirring time and start stirring at the same time. ② Open the video to observe the thickening of the ice layer. When the No. II concentration tank automatically completes the first to fifth stage continuous frozen concentration program, or the ice layer in the No. II concentration tank approaches the stirring blade, stop stirring, open the tank cover and remove the stirring blade, and take a small amount of concentrated liquid from the No. II concentration tank to determine its concentration. ③ When the concentrated liquid still does not reach the expected concentration, all the second-stage frozen concentrate is transported to the No. III frozen concentration tank, the second-stage frozen concentration is terminated, and the operation step 3 is performed to complete the third-stage frozen concentration of the No. III concentration tank; when the expected concentration has been reached, the freeze concentration is terminated and the third-stage frozen concentration is no longer performed. ④At the same time, set the thawing temperature and thawing time of the No. II concentration tank, start the heater and circulation pump of the normal temperature refrigerant tank and the circulation of the normal temperature refrigerant in the outer interlayer of the No. II concentration tank, and after the thawing of the ice ring of the No. II concentration tank is completed, the outer ring of the ice ring is separated from the inner wall of the No. II concentration tank. ⑤Take out the ice ring in the No. II concentration tank, break it, and use the matching centrifuge to recover the entrained liquid in the ice. The recovered entrained liquid can be added to the III concentration tank for mixing, and the remaining secondary white ice can be discarded. ⑥Furthermore, before the secondary freeze concentration reaches the expected target concentration and ends the operation of the whole machine, the secondary freeze concentration process data can be exported using a U disk, the equipment can be cleaned, and the power can be turned off. At this point, the secondary freeze concentration of the primary frozen concentrate in the No. II concentration tank and the deicing operation in the No. II concentration tank are all completed.

[0026] Operation step three: When the secondary frozen concentrate does not reach the target concentration and needs to be subjected to the tertiary frozen concentration, the third concentration tank immediately starts the tertiary frozen concentration of the second frozen concentrate after receiving the second frozen concentrate, and completes the ice ring thawing and de-icing operation after the freeze concentration is completed. ① Referring to the center temperature in the tank when the secondary frozen concentration is completed, set the first to fifth freeze concentration temperature range and the operating time parameters of each section of the third concentration tank on the operation panel, start the freeze concentration of the third concentration tank, and set the stirring time and start stirring at the same time. ② Open the video to observe the thickening of the ice layer. When the third concentration tank automatically completes the first to fifth continuous freeze concentration procedures, or the ice layer in the third concentration tank approaches the stirring blade, stop stirring, open the tank cover and remove the stirring blade, and take a small amount of concentrated liquid from the third concentration tank to determine its concentration. ③ When the concentrate still does not reach the expected concentration, the third-level freeze concentration can be terminated first, and all the third-level frozen concentrate can be collected in a temporary storage container; when the expected concentration has been reached, the freeze concentration is terminated and the fourth-level freeze concentration is no longer performed. ④At the same time, set the thawing temperature and thawing time of the No. III concentration tank, start the heater and circulation pump of the normal temperature coolant tank and the circulation of the normal temperature coolant in the outer interlayer of the No. III concentration tank, and after the thawing of the ice ring of the No. III concentration tank is completed, the outer ring of the ice ring is separated from the inner wall of the No. III concentration tank. ⑤Take out the ice ring in the No. III concentration tank, break it, and use the matching centrifuge to recover the entrained liquid in the ice cubes. The recovered entrained liquid can be added to the temporary storage container and mixed with the tertiary concentrate, and the remaining tertiary white ice can be discarded. ⑥Furthermore, before the tertiary freeze concentration reaches the expected target concentration and ends the operation of the whole machine, the U disk can be used to export the tertiary freeze concentration process data, clean the equipment, and turn off the power. At this point, the tertiary freeze concentration of the secondary frozen concentrate in the No. III concentration tank and the deicing operation in the No. III concentration tank are all completed.

[0027] Furthermore, for progressive freeze concentration, in actual situations, most feed solutions with suitable initial concentrations usually only need to complete two to three stages of freeze concentration to reach the desired target concentration or a maximum ultimate concentration of 50% (w / w); only some feed solutions with lower initial concentrations require four or more stages of freeze concentration.

[0028] Operation step 4: If the tertiary frozen concentrate still cannot reach the expected target concentration, the above operation steps 1, 2, and 3 can be repeated by sequentially cycling the No. I, No. II, and No. III concentration tanks, and a new round of one-stage, two-stage, and three-stage continuous freeze concentrations can be performed on the initial liquid in turn. A sufficient volume of the tertiary frozen concentrate can be collected, and then the No. I, No. II, and No. III concentration tanks of this equipment can be sequentially cycled, starting with the tertiary frozen concentrate, and four or more freeze concentration operations can be performed in turn to finally reach the target concentration. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1It is a schematic diagram of the structural layout of a high-performance progressive freeze concentration experimental equipment capable of continuous multi-stage concentration;

[0030] In the figure: 1- intelligent operation control system; 2- refrigeration system; 3- low temperature refrigerant tank; 4- normal temperature refrigerant tank; 5- No. I concentration tank; 6- No. II concentration tank; 7- No. III concentration tank; 8- heat exchanger; 9, 10, 11, 12, 13, 14 and 15- respectively refrigerant circulation pump No. 1, pump No. 2, pump No. 3, pump No. 4, pump No. 5, pump No. 6 and pump No. 7; 16- heater; 17 and 18- respectively feed liquid Pump No. 1 and Pump No. 2; 19, 20 and 21 - stirring devices No. 1, No. 2 and No. 3 respectively; 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34 and 35 - valves No. 1, No. 2, No. 3, No. 4, No. 5, No. 6, No. 7, No. 8, No. 9, No. 10, No. 11, No. 12, No. 13 and No. 14 respectively; 36 and 37 - liquid pump No. 1 and liquid pump No. 2 respectively.

[0031] Figure 2 , Figure 3 and Figure 4 Schematic diagrams of the flat rectangular-shaped freeze concentration tanks with sandwich structures, which are small-sized tanks ranging from 2L to 50L, medium-sized tanks ranging from 50L to 150L, ​​and large-sized tanks ranging from 150L to 500L;

[0032] In the figure: 38 - inner wall of the tank; 39 - outer wall of the tank interlayer; 40 - interlayer temperature probe; 41 - stirring paddle; 42, 48 - upper outlet pipe of the coolant; 43 - liquid inlet pipe; 44 - tank cover; 45 - camera device; 46 - stirring motor; 47 - LED light; 49 - tank inner wall temperature probe; 50, 54 - lower inlet pipe of the coolant; 51 - tank bottom temperature probe; 52 - tank bottom discharge pipe; 53 - concave tank bottom.

[0033] Figure 5 The invention discloses a continuous multi-stage freeze concentration process operation flow of a high-performance progressive freeze concentration experimental equipment capable of continuous multi-stage concentration. DETAILED DESCRIPTION

[0034] Example 1: High-performance progressive freeze concentration experimental equipment capable of continuous multi-stage concentration

[0035] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0036] See also Figures 1 to 5As shown, the high-performance progressive freezing concentration experimental equipment capable of continuous multi-stage concentration, its core structural components include an intelligent operation control system 1, a refrigeration system 2, a low-temperature coolant tank 3, a normal temperature coolant tank 4, a concentration tank No. I 5, a concentration tank No. II 6 and a concentration tank No. III 7.

[0037] Furthermore, the refrigeration system 2 is connected to the low-temperature refrigerant tank 3 through the heat exchanger 8 and the refrigerant circulation pump No. 1 9 to form a low-temperature refrigerant circulation, which can continuously adjust the required temperature of the refrigerant in the low-temperature refrigerant tank, and realize the freeze concentration of the corresponding feed liquid when the concentration tank No. I 5, the concentration tank No. II 6 and the concentration tank No. III 7 are freeze-concentrated in turn.

[0038] Furthermore, when freeze concentration is carried out, the low-temperature refrigerant tank 3 inputs the low-temperature refrigerant from the two refrigerant inlets at the bottom of the outer interlayer of the No. I concentrator tank through the refrigerant circulation No. 2 pump 10, No. 1 valve 22 and the stainless steel circulation pipe, and the refrigerant is refluxed to the low-temperature refrigerant tank 3 through the two refrigerant outlets at the top of the outer interlayer of the No. I concentrator tank, the stainless steel circulation pipe and the No. 2 valve 23, thus forming an independent low-temperature refrigerant circulation for the No. I concentrator tank; the low-temperature refrigerant is input from the two refrigerant inlets at the bottom of the outer interlayer of the No. II concentrator tank through the refrigerant circulation No. 3 pump 11, No. 3 valve 24 ... The brine is returned to the low-temperature brine tank 3 through the two upper brine outlets of the outer interlayer of the II concentrator tank, the stainless steel circulation pipe and the No. 4 valve 25, thus forming an independent low-temperature brine circulation for the II concentrator tank; the low-temperature brine tank 3 inputs the low-temperature brine from the two lower brine inlets of the outer interlayer of the III concentrator tank through the brine circulation pump No. 4 12, the No. 5 valve 26 and the stainless steel circulation pipe, and the brine is returned to the low-temperature brine tank 3 through the two upper brine outlets of the outer interlayer of the III concentrator tank, the stainless steel circulation pipe and the No. 6 valve 27, thus forming an independent low-temperature brine circulation for the III concentrator tank. In particular, when there is only one refrigeration compressor in the refrigeration system 2, and when the I concentrator tank 5, the II concentrator tank 6 and the III concentrator tank 7 share the low-temperature brine tank 3, only one of the I concentrator tank 5, the II concentrator tank 6 and the III concentrator tank 7 can perform freeze concentration, and freeze concentration cannot be performed synchronously;

[0039] Preferably, when there are three refrigeration compressors in the refrigeration system 2, and equipped with three heat exchangers and three independent low-temperature refrigerant tanks, they can form independent low-temperature refrigerant cycles with the concentration tank No. I 5, the concentration tank No. II 6 and the concentration tank No. III 7 respectively, and the concentration tank No. I 5, the concentration tank No. II 6 and the concentration tank No. III 7 can perform freeze concentration synchronously to achieve more efficient continuous freeze concentration operation.

[0040] Furthermore, after the freeze concentration of concentration tank No. I 5 is completed, the concentrated liquid can be transported to concentration tank No. II 6 through liquid pump No. 1 17 for the next stage of freeze concentration; after the freeze concentration of concentration tank No. II 6 is completed, the concentrated liquid can be transported to concentration tank No. III 7 through liquid pump No. 2 18 for the next stage of freeze concentration; and after the freeze concentration of concentration tank No. III 7 is completed, the concentrated liquid can be released and collected in a temporary storage container. If further freeze concentration is required, multiple batches of frozen concentrates in concentration tank No. III 7 can be collected for a new round of multi-stage freeze concentration until the target concentration is reached.

[0041] Furthermore, when the ice ring is thawed after the freeze concentration is completed, the normal temperature refrigerant tank 4 can drive and adjust the refrigerant in the normal temperature refrigerant tank 4 to maintain room temperature through the refrigerant circulation pump No. 7 15, heater 16, valve No. 14 and circulation pipe outside the tank; the normal temperature refrigerant tank 4 inputs the normal temperature refrigerant into the outer interlayer of No. 1 concentration tank 5 through the refrigerant circulation pump No. 5 and valve No. 7 28 using the two refrigerant inlets at the bottom of the outer interlayer of No. 1 concentration tank 5 and the original stainless steel circulation pipe, and then flows back to the normal temperature refrigerant tank 4 from the two refrigerant outlets at the top of the outer interlayer of No. 1 concentration tank 5 and the original stainless steel circulation pipe and valve No. 8 29 to form a normal temperature refrigerant circulation, quickly thawing the ice layer connected to the inner wall of the tank and the ice ring, which is convenient for timely de-icing; similarly, the normal temperature refrigerant tank 4 The warm refrigerant tank 4 is connected to the two refrigerant inlets at the bottom of the outer interlayer of No. II concentrator tank 6 and No. III concentrator tank 7 and the original stainless steel circulation pipe through the refrigerant circulation pump No. 6 and valve No. 9 30, and by controlling the alternating closing and opening of valve No. 10 31 and valve No. 11 32, and is successively input into the outer interlayer of No. II concentrator tank 6 and No. III concentrator tank 7, and then refluxes to the normal temperature refrigerant tank 4 from the two refrigerant outlets at the top of the outer interlayer of No. II concentrator tank 6 and No. III concentrator tank 7 and the original stainless steel circulation pipe, No. 13 valve 33 and No. 14 valve 34 to form their own normal temperature refrigerant circulation, which can successively realize the independent thawing of the ice rings of No. II concentrator tank 6 and No. III concentrator tank 7, and facilitate timely deicing.

[0042] Furthermore, if Figures 2 to 4 As shown, the No. I, No. II and No. III concentration tanks are all equipped with LED lighting 47 and real-time camera devices 45 on the top of the tank lids, which can observe, photograph or record the freezing concentration process and ice ring growth process in the corresponding tanks in real time.

[0043] Furthermore, if Figure 1As shown, the concentration tank No. I 5, the concentration tank No. II 6 and the concentration tank No. III 7 are schematically installed with stirring devices 19, 20 and 21 respectively. However, in particular, no matter whether it is the stirring device 19, the stirring device 20 or the stirring device 21, it does not only represent one stirring device. Further, the number of stirring devices actually installed in the concentration tank No. I 5, the concentration tank No. II 6 and the concentration tank No. III 7 must be determined according to the aforementioned planning of "the volume of the concentration tank No. I is between 10L and 500L; when the volume model of the concentration tank No. I is determined, the volume of the concentration tank No. II is 50% to 100% of that of the concentration tank No. I, and the volume of the concentration tank No. III is 50% to 100% of that of the concentration tank No. II". Further, no matter whether it is the concentration tank No. I 5, the concentration tank No. II 6 or the concentration tank No. III 7, their volumes may all be between 150L and 500L, or between 50L and 140L, or between 2L and 50L. Then, if Figures 2 to 4 As shown, whether it is the I concentration tank 5, the II concentration tank 6 or the III concentration tank 7, the number of stirring devices installed in each of them may be 1 to 3, so the number of stirring devices installed in each of the I concentration tank 5, the II concentration tank 6 and the III concentration tank 7 can be determined according to their actual volume range. In particular, when the number of stirring devices installed in the concentration tank reaches 2 or 3, the direction of rotation of the stirring motor is opposite in sequence, which is more conducive to the uniform flow of the liquid in the tank, accelerates the heat transfer and cooling of the liquid, and eliminates the concentration polarization on the surface of the ice layer.

[0044] In particular, the intelligent operation control system 1 is equipped with a PLC operation panel, data processing and automatic control module software, a record storage and various supporting electrical control components; the various supporting electrical control components are respectively connected to the refrigeration system 2, the heat exchanger 8, the low-temperature coolant tank 3, the normal temperature coolant tank 4, and the No. I concentration tank 5, the No. II concentration tank 6, the No. III concentration tank 7 and the corresponding number of temperature probes, stirring devices, LED lighting and real-time camera devices in the supporting tanks, No. 1 to 7 circulation pumps and No. 1 to 14 valves, etc., to achieve the setting and modification of the freezing concentration operation parameters, automatic operation of the whole machine, remote monitoring, and real-time display, storage and export of operation parameters, data, and image data.

[0045] Example 2: One-stage to multi-stage continuous freeze concentration in a progressive freeze concentration experimental device

[0046] The following will be combined with the attached examples of the present application Figures 1 to 5 , the one-stage to multi-stage continuous freeze-concentration operation steps in the embodiments of the present application are clearly and completely described.

[0047] Operation step 1: First-stage freeze concentration and deicing operation of the initial liquid in the concentration tank 5:

[0048] Turn on the power of the equipment and open the intelligent operation control system 1; transport the initial liquid to the No. 1 concentration tank 5 and reach the corresponding volume. At this time, all the refrigerant circulation pumps and all valves in the equipment are in the closed state.

[0049] First, referring to the freezing point and supercooling point of the initial feed liquid, set the first temperature range of the No. 1 concentration tank 5 on the operation panel, the time is 1 to 3 hours; the second, third, fourth and fifth temperature ranges are 2 to 4°C lower than the previous one, and the time is 1 to 3 hours; start the refrigeration system 2 (including synchronous start of the heat exchanger 8 and the refrigerant circulation pump No. 1 9), start the low-temperature refrigerant circulation of the No. 1 concentration tank 5 (including synchronous start of the refrigerant circulation pump No. 2 10, open the No. 1 valve 22 and the No. 2 valve 23) to start freeze concentration; at the same time, set the stirring time of the No. 1 concentration tank 5 and start the No. 1 stirring device 19 (1 to 3 stirring devices), and the equipment automatically runs the first to fifth stages of freeze concentration of the No. 1 concentration tank 5.

[0050] The LED light 47 and the camera device 45 of the No. 1 concentration tank 5 can be turned on during the process to observe the thickening of the ice layer in the tank. When the ice layer in the No. 1 concentration tank 5 is close to the stirring blades, the stirring device 19 (including 1 to 3 stirring devices) is stopped, the tank cover is opened and the stirring paddle is removed, and a small amount of concentrated liquid is released from the valve at the bottom of the No. 1 concentration tank 5 to determine its concentration.

[0051] When the primary concentrate does not reach the expected concentration and needs secondary freeze concentration, the low-temperature coolant circulation of the No. I freeze concentration tank 5 is closed to end the primary freeze concentration, and the No. 1 material pump 17 is started to transport all the primary freeze concentrate to the No. II freeze concentration tank 6 and start the secondary freeze concentration; when the expected concentration has been reached, the secondary freeze concentration is no longer performed. At the same time, the thawing temperature (usually 10-15°C) and thawing time (usually 0.5-1h) of the No. I concentration tank 5 can be set in advance on the operation panel, and the normal temperature coolant circulation of the normal temperature coolant tank 4 is started (including synchronously opening the No. 14 valve 35, starting the coolant circulation No. 7 pump 15 and the heater 16).

[0052] Start the normal temperature refrigerant circulation in the outer interlayer of the No. 1 concentrator tank 5 (including opening the No. 7 valve 28 and the No. 8 valve 29 synchronously, and start the refrigerant circulation pump No. 5 13), and complete the thawing of the outer ring of the ice ring in the No. 1 concentrator tank 5. After the outer ring of the ice ring is thawed, close the normal temperature refrigerant circulation of the normal temperature refrigerant tank 4 and the normal temperature refrigerant circulation in the outer interlayer of the No. 1 concentrator tank 5, open the lid of the No. 1 concentrator tank 5, take out the ice ring, break it, and use the matching centrifuge to recover the entrained liquid in the ice. The recovered entrained liquid can be added to the No. II concentrator tank 6 for mixing, and the remaining first-level white ice can be discarded.

[0053] Furthermore, when the primary freeze concentration reaches the expected target concentration and before the whole machine operation is terminated, the primary freeze concentration process data can be exported using a USB flash drive, the equipment is cleaned, and the power is turned off. At this point, the primary freeze concentration of the initial feed liquid in the No. 1 concentration tank 5 and the deicing operation in the No. 1 concentration tank 5 are all completed.

[0054] Operation step 2: When the first-stage frozen concentrate does not reach the target concentration and needs to be subjected to second-stage frozen concentration, the second-stage frozen concentration is immediately started after the concentration tank II 6 receives the first-stage frozen concentrate.

[0055] With reference to the center temperature in the tank when the first-stage freeze concentration is completed, the first temperature range of No. II concentration tank 6 is set on the operation panel for 1 to 3 hours; the second, third, fourth and fifth temperature ranges are 3 to 4°C lower than the previous ones, and the time is 1 to 3 hours; start the low-temperature refrigerant circulation of No. II concentration tank 6 (including synchronously starting refrigerant circulation pump No. 3 11, opening valve No. 3 24 and valve No. 4 25) to start the second-stage freeze concentration; at the same time, set the stirring time of No. II concentration tank 6 and start stirring device No. 2 20 (1 to 3 stirring devices), and the equipment automatically runs the first to fifth stages of freeze concentration of No. II concentration tank 6.

[0056] The LED light 47 and the camera device 45 of the No. II concentration tank 6 can be turned on during the process to observe the thickening of the ice layer in the tank. When the ice layer in the No. II concentration tank 6 is close to the stirring blades, the stirring device 20 (1 to 3 stirring devices) is stopped, the tank cover is opened and the stirring paddle is removed, and a small amount of concentrated liquid is released from the bottom of the No. II concentration tank 6 to determine its concentration.

[0057] When the secondary concentrated liquid does not reach the expected concentration and needs to be subjected to the tertiary freeze concentration, the low-temperature refrigerant circulation of the II frozen concentration tank 6 is closed to end the secondary frozen concentration, and the No. 2 material pump 18 is started to transport all the secondary frozen concentrated liquid to the III frozen concentration tank 7 and start the secondary frozen concentration; when the expected concentration has been reached, the tertiary freeze concentration is no longer performed. At the same time, the thawing temperature (usually 10-15°C) and thawing time (usually 0.5-1h) of the II concentration tank 6 can be set in advance on the operation panel, and the normal temperature refrigerant circulation of the normal temperature refrigerant tank 4 is started (including synchronously opening the No. 14 valve 35, starting the refrigerant circulation No. 7 pump 15 and the heater 16).

[0058] Start the normal temperature refrigerant circulation in the outer interlayer of No. II concentrator 6 (including synchronously opening valve No. 9 30, valve No. 10 31, valve No. 12 33, and starting the refrigerant circulation pump No. 6 14), and complete the thawing of the outer ring of the ice ring in No. II concentrator 6. After the outer ring of the ice ring is thawed, close the normal temperature refrigerant circulation of the normal temperature refrigerant tank 4 and the normal temperature refrigerant circulation in the outer interlayer of No. II concentrator 6, open the lid of No. II concentrator 6, take out the ice ring, break it, and use the matching centrifuge to recover the entrained liquid in the ice. The recovered entrained liquid can be added to No. III concentrator 7 for mixing, and the remaining secondary white ice can be discarded.

[0059] Furthermore, when the secondary freeze concentration reaches the expected target concentration and before the whole machine operation is terminated, the secondary freeze concentration process data can be exported using a USB flash drive, the equipment is cleaned, and the power is turned off. At this point, the secondary freeze concentration of the initial feed liquid in the II concentration tank 6 and the deicing operation in the II concentration tank 6 are all completed.

[0060] Operation step three: When the secondary frozen concentrate does not reach the target concentration and needs to be subjected to tertiary frozen concentration, the third-stage frozen concentration is immediately started after the concentration tank III 7 receives the secondary frozen concentrate.

[0061] Referring to the center temperature in the tank when the secondary freeze concentration is completed, set the first temperature range of No. III concentration tank 7 on the operation panel, the time is 1 to 3 hours; the second, third, fourth and fifth temperature ranges are 3 to 4°C lower than the previous one, and the time is 1 to 3 hours; start the low-temperature refrigerant circulation of No. III concentration tank 7 (including synchronously starting the refrigerant circulation pump No. 4 12, opening the valve No. 5 26 and the valve No. 6 27) to start the third stage freeze concentration; at the same time, set the stirring time of No. III concentration tank 7 and start the stirring device No. 3 21 (1 to 3 stirring devices), and the equipment automatically runs the first to fifth stages of freeze concentration of No. III concentration tank 7.

[0062] During the process, the LED light 47 and the camera device 45 of the No. III concentration tank 7 can be turned on to observe the thickening of the ice layer in the tank. When the ice layer in the No. III concentration tank 7 is close to the stirring paddle blades, the stirring of the No. 3 stirring device 21 (1 to 3 stirring devices) is stopped, the tank cover is opened and the stirring paddle is removed, and a small amount of concentrated liquid is released from the valve at the bottom of the No. III concentration tank 7 to determine its concentration.

[0063] When the third-level concentrated liquid does not reach the expected concentration and needs to be subjected to the fourth-level freeze concentration, the low-temperature coolant circulation of the III freeze concentration tank 7 is closed to end the third-level freeze concentration, and the third-level frozen concentrated liquid of the III freeze concentration tank 7 is all transferred to the temporary storage container for collection; when the expected concentration has been reached, the fourth-level freeze concentration is no longer performed. At the same time, the thawing temperature (usually 10-15°C) and thawing time (usually 0.5-1h) of the III concentration tank 7 can be set in advance on the operation panel, and the normal temperature coolant circulation of the normal temperature coolant tank 4 is started (including synchronously opening the No. 14 valve 35, starting the coolant circulation No. 7 pump 15 and the heater 16).

[0064] Start the normal temperature refrigerant circulation in the outer interlayer of the III concentrator tank 7 (including closing the No. 10 valve 3 synchronously, opening the No. 9 valve 30, the No. 11 valve 32, the No. 13 valve 34, and starting the refrigerant circulation No. 6 pump 14), and complete the thawing of the outer ring of the ice ring in the III concentrator tank 7. After the outer ring of the ice ring is thawed, close the normal temperature refrigerant circulation of the normal temperature refrigerant tank 4 and the normal temperature refrigerant circulation in the outer interlayer of the III concentrator tank 7, open the lid of the III concentrator tank 7, take out the ice ring, break it, and use the matching centrifuge to recover the entrained liquid in the ice. The recovered entrained liquid can be added to the temporary storage container for mixing, and the remaining three-level white ice can be discarded.

[0065] Furthermore, when the tertiary freeze concentration reaches the expected target concentration and before the whole machine operation is terminated, the tertiary freeze concentration process data can be exported using a USB flash drive, the equipment is cleaned, and the power is turned off. At this point, the tertiary freeze concentration of the initial feed liquid in the III concentration tank 7 and the deicing operation in the III concentration tank 7 are all completed.

[0066] Furthermore, for progressive freeze concentration, in actual situations, most feed solutions with a certain initial concentration usually only need to complete two to four stages of freeze concentration to reach the desired target concentration or a maximum ultimate concentration of 50% (w / w); only some feed solutions with a lower initial concentration require more than four stages of freeze concentration.

[0067] Operation step 4: If the tertiary frozen concentrate still cannot reach the expected target concentration, it is necessary to repeat the above operation steps 1, 2, and 3 in a sequential cycle from concentration tank No. I 5 to concentration tank No. II 6 and then to concentration tank No. III 7, and perform a new round of primary, secondary and tertiary continuous freeze concentration on the initial liquid in sequence, collect a sufficient volume of tertiary frozen concentrate, and then use the equipment to cycle from concentration tank No. I 5 to concentration tank No. II 6 and then to concentration tank No. III 7 in sequence, starting from the tertiary frozen concentrate, perform four or more freeze concentration operations in sequence to finally reach the target concentration.

[0068] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A high-performance progressive freeze concentration experimental equipment capable of continuous multi-stage concentration, characterized in that: The core structure of the equipment includes No. I, No. II and No. III concentration tanks, a low-temperature coolant tank, a normal-temperature coolant tank, a refrigeration system and an intelligent operation control system.

2. The high-performance progressive freezing concentration experimental equipment capable of continuous multi-stage concentration according to claim 1, characterized in that: The No. I, No. II and No. III concentration tanks are all flat rectangular progressive freezing concentration tanks with stainless steel sandwich structures, wherein the volume of the No. I concentration tank is between 10L and 500L; when the volume model of the No. I concentration tank is determined, the volume of the No. II concentration tank is 50% to 100% of the No. I concentration tank, and the volume of the No. III concentration tank is 50% to 100% of the No. II concentration tank; The No. I, No. II and No. III concentrators have two stainless steel flat plates on the side of the middle part of the inner cavity of the tank body, which are combined with a stainless steel semi-cylindrical shell at each end of the tank body. The diameter and height of the stainless steel semi-cylindrical shell at the two ends are equal to the spacing and height of the two stainless steel flat plates. The bottom is a stainless steel concave component with the same shape and size as the cross-section of the tank body, which are welded together. Taking into account the maximum concentration efficiency and the convenience of operation, the size range of the two stainless steel flat plates in the middle of the tank body is: 10cm to 150cm in length, 15cm to 120cm in height, and the distance between the two plates is 8cm to 30cm. The outer layer of the No. I, No. II and No. III concentrators is a stainless steel outer interlayer. According to the heat transfer requirements of the concentrators of different volumes, the thickness of the coolant in the outer interlayer ranges from 1cm to 10cm. The outer interlayer bottom of the No. I, No. II and No. III concentration tanks each contains two coolant inlets, and the upper part of the outer interlayer contains two coolant outlets; the two coolant inlets are respectively installed at the obliquely symmetrical tangent positions of the combination of the semi-cylindrical outer interlayer at both ends of the freezing concentration tank body and the bottom of the rectangular outer interlayer, and the two coolant outlets are respectively installed at the obliquely symmetrical tangent positions of the combination of the semi-cylindrical outer interlayer at both ends of the freezing concentration tank body and the upper end of the rectangular outer interlayer; 1-2 temperature recording probes are installed in the outer interlayer of the No. I, No. II and No. III concentration tanks; 2 temperature recording probes are installed inside the tank, one of which is installed in one of the two semi-cylinders close to the middle of the inner wall to record the temperature change process of the solution near the inner wall of the tank, and the other is installed at the bottom of the tank close to the discharge port to record the temperature change process of the solution in the center of the tank; The shape of the tank cover of the No. I, No. II and No. III concentration tanks is consistent with the size of the tank edge at the upper end of the freezing concentration tank body, and is fixed and sealed by a sealing ring and a buckle; an LED lighting lamp and a real-time camera device are installed on the top of the tank cover, which can observe, take pictures or record the freezing concentration process and ice ring growth process in real time; The No. I, No. II and No. III concentration tanks are installed with 1 to 3 stirring devices according to their respective volume models, wherein a 2L to 50L small tank is installed with 1 stirring device, the stirring motor is installed at the geometric center position on the tank cover, the upper end of the stirring paddle is connected to the stirring motor shaft through a movable clamp, and the lower end of the stirring paddle is connected to the center of the movable disc at the bottom of the tank, and the stirring paddle can be removed when necessary; 50L to 150L medium-sized tanks are installed with 2 stirring devices, which are respectively installed in the middle of the 1st and 3rd dividing lines of the tank cover's transverse center axis divided into four equal parts, and the stirring motor and the stirring paddle are installed in the same manner as described above, but the directions of the two stirring motors are opposite; 150L to 500L large tanks are installed with 3 stirring devices, which are respectively installed in the middle of the 1st, 3rd and 5th dividing lines of the tank cover's transverse center axis divided into six equal parts, and the stirring motor and the stirring paddle are installed in the same manner as described above, but the directions of the three stirring motors are opposite in sequence.

3. The high-performance progressive freezing concentration experimental equipment capable of continuous multi-stage concentration according to claim 1, characterized in that: The low-temperature coolant tank forms a low-temperature coolant circulation with the refrigeration system, heat exchanger, etc. through a circulation pump, valves and pipelines, and can continuously adjust the required temperature of the coolant in the low-temperature coolant tank; the low-temperature coolant tank is simultaneously connected to the two coolant inlets and two coolant outlets of the outer interlayer of the No. I, No. II and No. III concentrator tanks through a circulation pump, valves and pipelines to form independent low-temperature coolant circulations, respectively, to achieve freeze concentration of the feed liquid in the corresponding concentrator tanks No. I, No. II and No. III; In particular, when there is only one refrigeration compressor in the refrigeration system, only one of the No. I, No. II and No. III concentration tanks can perform freeze concentration, and freeze concentration cannot be performed simultaneously; when there are three refrigeration compressors in the refrigeration system and are equipped with three heat exchangers respectively connected to the No. I, No. II and No. III concentration tanks to form independent low-temperature refrigerant cycles, the No. I, No. II and No. III concentration tanks can perform freeze concentration simultaneously to achieve more efficient continuous freeze concentration operation.

4. The high-performance progressive freezing concentration experimental equipment capable of continuous multi-stage concentration according to claim 1, characterized in that: The normal temperature refrigerant tank is loaded with normal temperature refrigerant, and only forms independent normal temperature refrigerant circulation with the outer interlayer of concentrating tanks No. I, II and III respectively through circulating pumps, pipelines and valves; the normal temperature refrigerant tank itself is equipped with a heater and a circulating pump, which can adjust the loaded refrigerant to a normal temperature state above 0°C. When the freeze concentration of the corresponding concentrating tanks No. I, II and III is completed, the normal temperature refrigerant circulation can be used to quickly thaw the ice layer on the joint surface of the inner wall of the corresponding concentrating tank and the ice ring, so as to facilitate the detachment and de-icing of the ice ring.

5. The high-performance progressive freezing concentration experimental equipment capable of continuous multi-stage concentration according to claim 1, characterized in that: The No. I, No. II and No. III concentration tanks are all flat rectangular structures with different capacity specifications ranging from 2L to 500L. The half-width size of the rectangular section in the tank cavity of these concentration tanks and the radius of the semi-cylindrical semi-circular section at both ends are both in the range of 4cm to 15cm. This tank cavity structure can limit the thickest ice layer formed on each single cold wall surface in the tank to ≤4cm to 15cm. Under the same concentration ratio, the thickness of the ice layer on these flat rectangular progressive freezing concentration tanks will be much smaller than the ice layer thickness of 6.5cm to 32.5cm of the circular progressive freezing concentration tank of the same volume. The thinner ice layer will significantly improve the heat transfer efficiency between the inner wall of the concentration tank and the liquid in the center of the tank, thereby greatly shortening the freezing concentration time, improving the concentration efficiency and reducing the energy consumption of equipment operation.

6. The high-performance progressive freezing concentration experimental equipment capable of continuous multi-stage concentration according to claim 1, characterized in that: The intelligent operation control system is composed of an operation panel, a data processing and automatic control module, a recording storage, and an electrical control element; the electrical control element is respectively connected to the refrigeration system, a heat exchanger, a low-temperature coolant tank, a normal-temperature coolant tank, a concentration tank No. I, a concentration tank No. II, and a concentration tank No. III and their corresponding supporting circulation pumps, pipelines, temperature probes, stirring devices, LED lighting, and real-time camera devices, so as to realize the setting and adjustment of the freezing concentration operation parameters, automatic operation of the whole machine, remote monitoring, and real-time display, storage, and export of operation parameters, data, and image materials.

7. The high-performance progressive freezing concentration experimental equipment capable of continuous multi-stage concentration according to claim 1, characterized in that: The No. I, No. II and No. III concentrators are used in combination with a low-temperature coolant tank, a normal-temperature coolant tank, a refrigeration system and an operation control system in a multi-tank series manner. The No. I, No. II and No. III concentrators can independently run a freeze concentration program and a thawing program, respectively, and realize one-stage to multiple-stage continuous freeze concentration of the feed liquid by sequentially switching operations of the No. I, II and III concentrators in series until the feed liquid is concentrated to a target concentration or a maximum of 50% of the ultimate mass concentration; In particular, the No. I, No. II and No. III concentration tanks can be connected in series, starting from the initial feed liquid, from the No. I concentration tank to the No. II concentration tank and then to the No. III concentration tank, and can complete the first-stage, second-stage and third-stage freeze concentration in sequence; and during the next stage of freeze concentration, the thawing and deicing operations of the ice ring of the previous stage are completed synchronously; In particular, for the liquid with extremely low initial concentration, it is also possible to start with the third-stage frozen concentrated liquid, and then successively complete a new round of freeze concentration from the fourth stage to the fifth stage and then to the sixth stage in series from the No. I to the No. II and then the No. III concentration tanks, until the target concentration or the ultimate mass concentration of up to 50% is reached; and during the next stage of freeze concentration, the thawing and de-icing operations of the ice ring of the previous stage are completed simultaneously.

8. The intelligent operation control system according to claim 6, characterized in that: During the freeze concentration stage, the operation panel can independently set the freeze concentration temperature range and the corresponding operating time of the No. I, No. II and No. III concentration tanks respectively; further, the descending temperature range and the corresponding operating time during freeze concentration of the No. I, No. II and No. III concentration tanks can be independently set in a gradient segmented cooling sequence of one, two, three, four and five stages; further, the intelligent operation control system can automatically execute the freeze concentration process parameters of the first, second, third, fourth to fifth stages set for the No. I, No. II and No. III concentration tanks in sequence.

9. The intelligent operation control system according to claim 6, characterized in that: In the thawing stage after the freeze concentration is completed, the operation panel can independently set the ice ring thawing temperature and thawing time of each of the concentration tanks No. I, No. II and No. III; further, when any of the concentration tanks No. I, No. II and No. III after the freeze concentration is completed needs to be thawed, the thawing program can be executed separately, and the intelligent operation control system can automatically operate the heater and circulation pump of the normal temperature coolant tank, and synchronously start the normal temperature coolant circulation between the outer interlayer of the corresponding concentration tank and the normal temperature coolant tank to implement the thawing of the ice ring.

10. The high-performance progressive freezing concentration experimental equipment capable of continuous multi-stage concentration according to claim 1, characterized in that: Compared with the traditional single-tank intermittent freeze concentration equipment, the concentration efficiency and production efficiency of the equipment can be significantly improved in the following ways: when the equipment uses the No. I, No. II and No. III concentration tanks to perform one-stage to multi-stage freeze concentration on the relevant liquid, the concentrate of the previous stage can be immediately transported to the next concentration tank, seamlessly connected and perform the next stage of freeze concentration, the concentration process is continuous, and the concentration efficiency is improved; further, after the freeze concentration of any of the No. I, No. II and No. III concentration tanks of the equipment is completed, the independent normal temperature refrigerant circulation can be synchronously switched to perform rapid ice ring thawing and complete the deicing operation, which significantly improves the production efficiency; The equipment performs one-stage to multiple-stage continuous freeze concentration of the relevant liquid, while saving operation time and energy consumption and improving concentration production efficiency, which is achieved through the following steps: Operation step 1: First, complete the primary freeze concentration and deicing operation of the initial liquid in the No. 1 concentration tank: ① Turn on the power of the equipment and open the intelligent operation control system; transport the initial liquid to the No. 1 concentration tank to reach the corresponding volume; ② Set the freeze concentration temperature range of the first to fifth stages of the No. 1 concentration tank and the operating time parameters of each stage on the operation panel, start the freeze concentration of the No. 1 concentration tank, and set the stirring time and start stirring; ③ Open the video to observe the thickening of the ice layer. When the No. 1 concentration tank automatically completes the first to fifth stages of continuous freeze concentration procedures, or the ice layer in the No. 1 concentration tank approaches the stirring blade, stop stirring, open the tank cover and remove the stirring blade, and take a small amount of concentrated liquid from the No. 1 concentration tank to determine its concentration; ④ If the concentrate still does not reach the expected concentration, all the first-stage frozen concentrate is transported to the No. II frozen concentration tank, and the first-stage frozen concentration is terminated; if the expected concentration has been reached, the frozen concentration is terminated and the second-stage frozen concentration is no longer performed; ⑤ At the same time, set the thawing temperature and thawing time of the No. I concentrator tank, start the heater and circulation pump of the normal temperature coolant tank and the circulation of the normal temperature coolant in the outer interlayer of the No. I concentrator tank, and after the thawing of the ice ring of the No. I concentrator tank is completed, the outer ring of the ice ring is separated from the inner wall of the No. I concentrator tank; take out the ice ring in the No. I concentrator tank, break it, and use the matching centrifuge to recover the entrained liquid in the ice. The recovered entrained liquid can be added to the II concentrator tank for mixing, and the remaining first-level white ice can be discarded; ⑥ Further, when the first-stage freeze concentration reaches the expected target concentration and before the whole machine operation is terminated, the first-stage freeze concentration process data can be exported using a USB flash drive, the equipment is cleaned, and the power is turned off. At this point, the first-stage freeze concentration and deicing operation of the initial feed liquid in the No. 1 concentration tank is completely completed; Operation step 2: completing the secondary freeze concentration and deicing operation of the primary frozen concentrate in the concentration tank II; ① Referring to the center temperature of the tank before the end of the previous freeze concentration, set the freeze concentration temperature range of the first to fifth stages of the No. II concentration tank and the operating time parameters of each stage on the operation panel, start the freeze concentration of the No. II concentration tank, set the stirring time and start stirring at the same time; ② Open the video to observe the thickening of the ice layer. When the No. II concentration tank automatically completes the first to fifth continuous freeze concentration procedures, or the ice layer in the No. II concentration tank approaches the stirring blade, stop stirring, open the tank cover and remove the stirring blade, and take a small amount of concentrated liquid from the No. II concentration tank to determine its concentration; ③ If the concentrate still does not reach the expected concentration, the secondary freeze concentration is terminated, and all the secondary freeze concentrate is transferred to the No. III freeze concentration tank, and the operation step 3 is performed to complete the tertiary freeze concentration of the No. III concentration tank; if the expected concentration has been reached, the freeze concentration is terminated, and the tertiary freeze concentration is no longer performed; ④ At the same time, set the thawing temperature and thawing time of the No. II concentrator tank, start the heater and circulation pump of the normal temperature coolant tank and the circulation of the normal temperature coolant in the outer interlayer of the No. II concentrator tank, and after the thawing of the ice ring of the No. II concentrator tank is completed, the outer ring of the ice ring is separated from the inner wall of the No. II concentrator tank; take out the ice ring in the No. II concentrator tank, break it, and use the matching centrifuge to recover the entrained liquid in the ice. The recovered entrained liquid can be added to the III concentrator tank for mixing, and the remaining secondary white ice can be discarded; ⑤ Further, when the secondary freeze concentration reaches the expected target concentration and before the whole machine operation is terminated, the secondary freeze concentration process data can be exported using a USB flash drive, the equipment can be cleaned, and the power can be turned off; at this point, the secondary freeze concentration of the primary frozen concentrate in the No. II concentration tank and the deicing operation in the No. II concentration tank are all completed; Operation step three: completing the tertiary freeze concentration and deicing operation of the secondary frozen concentrate in the concentration tank III; ① Referring to the center temperature of the tank before the end of the previous freeze concentration, set the freeze concentration temperature range of the first to fifth stages of the III concentration tank and the operating time parameters of each stage on the operation panel, start the freeze concentration of the III concentration tank, set the stirring time and start stirring at the same time; ② Open the video to observe the thickening of the ice layer. When the No. III concentration tank automatically completes the first to fifth continuous freeze concentration procedures, or the ice layer in the No. III concentration tank approaches the stirring blade, stop stirring, open the tank cover and remove the stirring blade, and take a small amount of concentrated liquid from the No. III concentration tank to determine its concentration; ③ If the concentrate still does not reach the expected concentration, the third-stage freeze concentration can be terminated first, and all the third-stage freeze concentration can be collected into a temporary container for preparation for the fourth-stage freeze concentration; if the expected concentration has been reached, the freeze concentration is terminated and the fourth-stage freeze concentration is no longer performed; ④ At the same time, set the thawing temperature and thawing time of the III concentrator tank, start the heater and circulation pump of the normal temperature coolant tank and the circulation of the normal temperature coolant in the outer interlayer of the III concentrator tank, and after the thawing of the ice ring of the III concentrator tank is completed, the outer ring of the ice ring is separated from the inner wall of the III concentrator tank; take out the ice ring in the III concentrator tank, break it, and use the matching centrifuge to recover the entrained liquid in the ice. The recovered entrained liquid can be added to the temporary storage container and mixed with the third-level concentrated liquid, and the remaining third-level white ice can be discarded; ⑤ Further, when the tertiary freeze concentration reaches the expected target concentration and before the whole machine operation is terminated, the tertiary freeze concentration process data can be exported using a USB flash drive, the equipment can be cleaned, and the power can be turned off; at this point, the tertiary freeze concentration of the secondary frozen concentrate in the No. III concentration tank and the deicing operation in the No. III concentration tank are all completed; Operation step 4: If the three-stage frozen concentrate still cannot reach the expected target concentration, a new round of the above-mentioned one, two, and three steps can be repeated by using the serial sequential cycle from the No. I, No. II and No. III concentration tanks, and a new round of one, two and three-stage continuous freeze concentration can be performed on the initial liquid in sequence. After collecting a sufficient volume of the three-stage frozen concentrate, the series sequential cycle of the No. I, No. II and No. III concentration tanks of this equipment is used again, starting from the three-stage frozen concentrate, and four or more freeze concentration operations are performed in sequence to finally reach the target concentration; In particular, for progressive freeze concentration, in actual situations, most feed solutions with suitable concentrations usually only need to complete second to fourth stage freeze concentration to reach the desired target concentration or a maximum ultimate mass concentration of 50%; only some feed solutions with extremely low initial concentrations require more than four stages of freeze concentration.

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