Citric acid waste liquid regeneration device

Abstract

The utility model belongs to the technical field of citric acid production equipment, and particularly relates to a citric acid waste liquid regeneration device which comprises an extraction tank, a reduction tank fixedly mounted on one side of the extraction tank, a crystallization kettle fixedly mounted on one side, far away from the extraction tank, of the reduction tank, and a first conveying pipe fixedly connected between the extraction tank and the reduction tank. A second conveying pipe is fixedly connected between the reduction tank and the crystallization kettle, and a driving assembly is mounted at the bottom of the reduction tank; the extraction tank comprises a first feed port, a first rotating shaft, a first connecting rod and a first scraper, the first feed port is fixedly connected to the top of the extraction tank, the first rotating shaft is movably mounted in the extraction tank, the first connecting rod is fixedly connected to the outer wall of the first rotating shaft, and the first scraper is fixedly connected to the outer wall of the first connecting rod. According to the utility model, the regeneration treatment time of the citric acid waste liquid is shortened, the citric acid waste liquid can be uniformly stirred, the production efficiency and the product quality are improved, and in addition, the inner wall of the extraction tank can be cleaned.

Description

Technical Field

[0001] The utility model belongs to the technical field of citric acid production equipment, and particularly relates to a citric acid waste liquid regeneration device. Background Art

[0002] Citric acid is an important organic acid, which has functions such as mild sour taste, chelating metal ions and adjusting pH value, and is mainly applied in the fields of food, pharmaceuticals, industry and chemical engineering. In the food industry, it can be used as a sour agent, preservative and antioxidant; in the pharmaceutical industry, it can be used for drug synthesis and preparations; in the chemical industry, it can be used for surface treatment and cosmetics production, etc.

[0003] In the food industry, citric acid waste liquid will be generated during processes such as beverage production and canned food processing; in the pharmaceutical industry, waste water containing citric acid will be generated during some drug synthesis and pharmaceutical preparation processes; in the chemical industry, citric acid waste liquid will also be generated during production links such as surface treatment and cosmetics production. Since the direct discharge of citric acid waste liquid will pollute the environment and citric acid itself has a certain economic value, it is necessary to regenerate the citric acid waste liquid, and a citric acid waste liquid regeneration device is required.

[0004] The steps of using the existing citric acid waste liquid regeneration device to treat citric acid waste liquid are relatively cumbersome and the treatment time is relatively long. This not only reduces the production efficiency but also increases the production cost. In addition, the long treatment process will also lead to an increase in energy consumption, accelerated equipment wear, and affect the quality of the regenerated citric acid. Summary of the Invention

[0005] The purpose of the utility model is to provide a citric acid waste liquid regeneration device, which shortens the regeneration treatment time of citric acid waste liquid, can uniformly stir the citric acid waste liquid, improves the production efficiency and product quality, and can also clean the inner wall of the extraction tank.

[0006] To achieve the above purpose, the technical solution adopted by the utility model is: to provide a citric acid waste liquid regeneration device, which includes an extraction tank, a reduction tank is fixedly installed on one side of the extraction tank, a crystallization kettle is fixedly installed on the side of the reduction tank away from the extraction tank, a first feeding pipe is fixedly connected between the extraction tank and the reduction tank, a second feeding pipe is fixedly connected between the reduction tank and the crystallization kettle, and a driving component is installed at the bottom of the reduction tank; the extraction tank includes a first feeding port, a first rotating shaft, a first connecting rod and a first scraper, the first feeding port is fixedly connected to the top of the extraction tank, the first rotating shaft is movably installed inside the extraction tank, the outer wall of the first rotating shaft is fixedly connected to the first connecting rod, the outer wall of the first connecting rod is fixedly connected to the first scraper, and the first scraper is attached to the inner wall of the extraction tank.

[0007] Furthermore, the reduction tank includes a second feed inlet, a second rotating shaft, a second connecting rod, and a second scraper. The top of the reduction tank is fixedly connected to the second feed inlet. The second rotating shaft is movably installed inside the reduction tank. The outer wall of the second rotating shaft is fixedly connected to the second connecting rod. The outer wall of the second connecting rod is fixedly connected to the second scraper, and the second scraper is in contact with the inner wall of the reduction tank.

[0008] Furthermore, the crystallization kettle includes a third feed inlet, a third rotating shaft, a third connecting rod, and a third scraper. The top of the crystallization kettle is fixedly connected to the third feed inlet. The third rotating shaft is movably installed inside the crystallization kettle. The outer wall of the third rotating shaft is fixedly connected to the third connecting rod. The outer wall of the third connecting rod is fixedly connected to the third scraper, and the third scraper is in contact with the inner wall of the crystallization kettle.

[0009] Furthermore, a first water pump is fixedly installed on the first feed pipe, and a first filter is fixedly installed at the feed end of the first feed pipe. A second water pump is fixedly installed on the second feed pipe, and a second filter is fixedly installed at the feed end of the second feed pipe.

[0010] Furthermore, the bottom of the extraction tank is fixedly connected to a first discharge pipe, the bottom of the reduction tank is fixedly connected to a second discharge pipe, and the side wall of the crystallization kettle is fixedly connected to a third discharge pipe. Valves are installed inside the first discharge pipe, the second discharge pipe, and the third discharge pipe.

[0011] Furthermore, the drive assembly includes a one-way pulley groove, a double-groove pulley, a support frame, a third protective cover, a drive motor, and a drive belt. One-way pulley grooves are fixedly connected to the bottoms of the first rotating shaft and the third rotating shaft. A double-groove pulley is fixedly connected to the bottom of the second rotating shaft. The bottom of the reduction tank is fixedly connected to a support frame. A third protective cover is fixedly connected inside the support frame. A drive motor is fixedly installed inside the third protective cover. The bottom of the double-groove pulley is fixedly installed at the output end of the drive motor. A drive belt is fixedly installed between the one-way pulley groove and the double-groove pulley.

[0012] Furthermore, mounting seats are fixedly connected to the tops of the inner walls of the extraction tank, the reduction tank, and the crystallization kettle. Bearings are fixedly installed inside the three mounting seats. The tops of the first rotating shaft, the second rotating shaft, and the third rotating shaft are fixedly connected to the inner rings of the bearings.

[0013] Furthermore, a first protective cover is fixedly installed on the outer wall of the extraction tank, and a first heating wire is fixedly installed between the first protective cover and the extraction tank. A second protective cover is fixedly installed on the outer wall of the crystallization kettle, and a second heating wire is fixedly installed between the second protective cover and the crystallization kettle.

[0014] Compared with the prior art, the utility model has the following beneficial effects:

[0015] The utility model is provided with an extraction tank, a first feed inlet, a first connecting rod, a first scraper, a reduction tank, a second connecting rod, a second scraper, a crystallization kettle, a third connecting rod, a third scraper, a second heating wire, a first feed pipe and a second water pump. When in use, the citric acid waste liquid to be regenerated and the extraction liquid are added into the extraction tank through the first feed inlet. At the same time, the rotation of the first connecting rod and the first scraper is used to stir the citric acid waste liquid, so that citric acid and other soluble components are separated from the impurities in the waste liquid as much as possible. Then the mixed liquid is pumped into the first feed pipe and then discharged into the reduction tank. Next, an appropriate amount of reducing agent is added into the reduction tank, and then the stirring of the second connecting rod and the second scraper is used to ensure that the reaction proceeds evenly, so that the mixed liquid is reduced to generate citric acid. Then the second water pump is started to pump the citric acid into the crystallization kettle. Through the stirring of the third connecting rod and the third scraper and the heating of the second heating wire, the citric acid in the solution reaches the supersaturated state, so that the citric acid crystallizes out. The utility model shortens the regeneration treatment time of the citric acid waste liquid and improves the production efficiency.

[0016] The utility model is provided with a first rotating shaft, a second rotating shaft, a third rotating shaft, a one-way belt groove, a double-groove pulley, a driving motor and a driving belt. When in use, the driving motor is started, and the output end of the driving motor drives the double-groove pulley to rotate. The two one-way belt grooves are driven to rotate through the driving belt, so as to drive the first rotating shaft, the second rotating shaft and the third rotating shaft to rotate, and further drive the connecting rods in the extraction tank, the reduction tank and the crystallization kettle to rotate, so as to drive the three scrapers to rotate, scrape the impurities attached to the inner wall of the extraction tank, and ensure the cleanliness inside the utility model, so as to improve the product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the following drawings are only some embodiments of the present utility model. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0018] Figure 1 is the front view three-dimensional structure schematic diagram of the present utility model;

[0019] Figure 2 is the bottom view three-dimensional structure schematic diagram of the present utility model;

[0020] Figure 3 is the partial sectional three-dimensional structure schematic diagram of the present utility model;

[0021] Figure 4 isFigure 3 Schematic diagram of the enlarged structure at position A in [device name];

[0022] Figure 5 is Figure 3 Schematic diagram of the enlarged structure at position B in [device name].

[0023] In the figure: 1. Extraction tank; 101. First feed inlet; 102. First rotating shaft; 103. First connecting rod; 104. First scraper; 105. First discharge pipe; 2. Reduction tank; 201. Second feed inlet; 202. Second rotating shaft; 203. Second connecting rod; 204. Second scraper; 205. Second discharge pipe; 3. Crystallization kettle; 301. Third feed inlet; 302. Third rotating shaft; 303. Third connecting rod; 304. Third scraper; 305. Third discharge pipe; 4. First protective cover; 401. First heating wire; 5. Second protective cover; 501. Second heating wire; 6. First feeding pipe; 601. First water pump; 602. First filter; 7. Second feeding pipe; 701. Second water pump; 702. Second filter; 8. Driving assembly; 801. One-way belt groove; 802. Double-groove pulley; 803. Support frame; 804. Third protective cover; 805. Driving motor; 806. Driving belt; 9. Mounting seat; 10. Bearing. Detailed implementation manners

[0024] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present utility model clearer and more understandable, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present utility model and are not used to limit the present utility model.

[0025] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0026] It should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present utility model.

[0027] In addition, the terms "first" and "second" are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present utility model, "a plurality of" means two or more, unless otherwise specifically defined.

[0028] Referring to Figures 1-5 , a citric acid waste liquid regeneration device provided by an embodiment of the present utility model will now be described. A citric acid waste liquid regeneration device includes an extraction tank 1. A reduction tank 2 is fixedly installed on one side of the extraction tank 1. A crystallization kettle 3 is fixedly installed on the side of the reduction tank 2 away from the extraction tank 1. A first feed pipe 6 is fixedly connected between the extraction tank 1 and the reduction tank 2. A second feed pipe 7 is fixedly connected between the reduction tank 2 and the crystallization kettle 3. A driving assembly 8 is installed at the bottom of the reduction tank 2; The extraction tank 1 includes a first feed inlet 101, a first rotating shaft 102, a first connecting rod 103 and a first scraping plate 104. The first feed inlet 101 is fixedly connected to the top of the extraction tank 1. The first rotating shaft 102 is movably installed inside the extraction tank 1. The outer wall of the first rotating shaft 102 is fixedly connected to the first connecting rod 103. The outer wall of the first connecting rod 103 is fixedly connected to the first scraping plate 104. The first scraping plate 104 is in contact with the inner wall of the extraction tank 1.

[0029] During use, after adding the citric acid waste liquid to be regenerated and the extraction liquid into the extraction tank 1 through the first feed inlet 101, start the driving assembly 8 to drive the first rotating shaft 102 to rotate, thereby driving the first connecting rod 103 and the first scraping plate 104 to rotate, stirring the citric acid waste liquid to fully mix the citric acid waste liquid and the extraction liquid, so that citric acid and other soluble components can be better separated from the impurities in the waste liquid; The first scraping plate 104 is used to scrape the impurities adhering to the inner wall of the extraction tank 1 to ensure the cleanliness inside the present utility model.

[0030] The reduction tank 2 includes a second feed inlet 201, a second rotating shaft 202, a second connecting rod 203 and a second scraping plate 204. The second feed inlet 201 is fixedly connected to the top of the reduction tank 2. The second rotating shaft 202 is movably installed inside the reduction tank 2. The outer wall of the second rotating shaft 202 is fixedly connected to the second connecting rod 203. The outer wall of the second connecting rod 203 is fixedly connected to the second scraping plate 204. The second scraping plate 204 is in contact with the inner wall of the reduction tank 2.

[0031] During use, after the mixed solution enters the reduction tank 2 through the first feed pipe 6, a reducing agent is added to the reduction tank 2. The second rotating shaft 202 drives the second connecting rod 203 and the second scraper 204 to rotate, stirring the mixed solution to enable the reduction reaction to proceed evenly, improving the reduction effect; the second scraper 204 is used to scrape the impurities adhering to the inner wall of the reduction tank 2 to prevent the impurities from affecting the reaction.

[0032] The crystallization kettle 3 includes a third feed inlet 301, a third rotating shaft 302, a third connecting rod 303, and a third scraper 304. The top of the crystallization kettle 3 is fixedly connected with the third feed inlet 301. The third rotating shaft 302 is movably installed inside the crystallization kettle 3. The outer wall of the third rotating shaft 302 is fixedly connected with the third connecting rod 303. The outer wall of the third connecting rod 303 is fixedly connected with the third scraper 304. The third scraper 304 is in contact with the inner wall of the crystallization kettle 3.

[0033] During use, the third rotating shaft 302 drives the third connecting rod 303 and the third scraper 304 to rotate, making the citric acid in the solution reach supersaturation, so that citric acid crystallizes out.

[0034] A first water pump 601 is fixedly installed on the first feed pipe 6, and a first filter 602 is fixedly installed at the feed end of the first feed pipe 6. A second water pump 701 is fixedly installed on the second feed pipe 7, and a second filter 702 is fixedly installed at the feed end of the second feed pipe 7.

[0035] During use, the first water pump 601 generates suction to pump the mixed solution in the extraction tank 1 into the first feed pipe 6. The mixed solution enters the reduction tank 2 after being filtered by the first filter 602; the second water pump 701 pumps the citric acid in the reduction tank 2 into the crystallization kettle 3, and the mixed solution is filtered by the second filter 702, improving the production efficiency; the filter can block solid particles to ensure the smooth progress of the subsequent treatment process.

[0036] A first discharge pipe 105 is fixedly connected to the bottom of the extraction tank 1, a second discharge pipe 205 is fixedly connected to the bottom of the reduction tank 2, and a third discharge pipe 305 is fixedly connected to the side wall of the crystallization kettle 3. Valves are installed inside the first discharge pipe 105, the second discharge pipe 205, and the third discharge pipe 305.

[0037] After the treatment is completed, the valves inside the corresponding discharge pipes are opened to discharge the waste liquid in the extraction tank 1 and the reduction tank 2, and to discharge the citric acid in the crystallization kettle 3, which is convenient for control operation and cleaning.

[0038] The driving assembly 8 includes a one-way belt groove 801, a double-groove pulley 802, a support frame 803, a third protective cover 804, a driving motor 805, and a driving belt 806. One-way belt grooves 801 are fixedly connected to the bottoms of the first rotating shaft 102 and the third rotating shaft 302. A double-groove pulley 802 is fixedly connected to the bottom of the second rotating shaft 202. A support frame 803 is fixedly connected to the bottom of the reduction tank 2. A third protective cover 804 is fixedly connected inside the support frame 803. A driving motor 805 is fixedly installed inside the third protective cover 804. The bottom of the double-groove pulley 802 is fixedly installed at the output end of the driving motor 805. A driving belt 806 is fixedly installed between the one-way belt groove 801 and the double-groove pulley 802.

[0039] During use, start the driving motor 805. The output end of the driving motor 805 drives the double-groove pulley 802 to rotate, and drives the two one-way belt grooves 801 to rotate through the driving belt 806, thereby driving the first rotating shaft 102, the second rotating shaft 202, and the third rotating shaft 302 to rotate. It can achieve that one driving source drives multiple rotating shafts to rotate simultaneously, without the need for multiple driving sources to work simultaneously, so as to avoid repeated consumption of energy, save energy, and improve production efficiency.

[0040] Mounting seats 9 are fixedly connected to the tops of the inner walls of the extraction tank 1, the reduction tank 2, and the crystallization kettle 3. Bearings 10 are fixedly installed inside the three mounting seats 9. The tops of the first rotating shaft 102, the second rotating shaft 202, and the third rotating shaft 302 are all fixedly connected to the inner rings of the bearings 10.

[0041] During use, the bearings 10 provide support for the rotating shafts, enabling them to rotate stably and smoothly, ensuring the stable operation of the rotating shafts, reducing friction, thereby reducing wear and extending the service life.

[0042] A first protective cover 4 is fixedly installed on the outer wall of the extraction tank 1. A first heating wire 401 is fixedly installed between the first protective cover 4 and the extraction tank 1. A second protective cover 5 is fixedly installed on the outer wall of the crystallization kettle 3. A second heating wire 501 is fixedly installed between the crystallization kettle 3 and the second protective cover 5.

[0043] During use, the first heating wire 401 is used to heat the waste liquid in the extraction tank 1 to promote the separation of citric acid and other soluble components; the second heating wire 501 is used to heat the solution in the crystallization kettle 3 to promote the crystallization and precipitation of citric acid. Heating can improve the reaction speed and crystallization efficiency and shorten the treatment time.

[0044] Working principle: During use, first start the driving motor 805. The output end of the driving motor 805 drives the double-groove pulley 802 to rotate, and drives the two one-way belt grooves 801 to rotate through the driving belt 806, thereby driving the first rotating shaft 102, the second rotating shaft 202, and the third rotating shaft 302 to rotate.

[0045] Then, the citric acid waste liquid to be regenerated and the extraction liquid are added into the extraction tank 1 through the first feed port 101. Then, the first electric heating wire 401 is started to heat the internal citric acid waste liquid. At the same time, the rotation of the first connecting rod 103 and the first scraper 104 is used to stir the citric acid waste liquid, so that the citric acid waste liquid and the extraction solvent are fully mixed, the mass transfer rate of substances is increased, and citric acid and other soluble components are separated from the impurities in the waste liquid as much as possible.

[0046] Next, the first water pump 601 is turned on to generate suction, and the mixed liquid is pumped into the first conveying pipe 6 and then discharged into the internal part of the reduction tank 2. When the mixed liquid enters the first conveying pipe 6, the first filter 602 blocks the solid particles in the mixed liquid. When the mixed liquid enters the reduction tank 2, an appropriate amount of reducing agent is added into the internal part of the reduction tank 2, and the stirring of the second connecting rod 203 and the second scraper 204 ensures that the reaction proceeds evenly, so that the mixed liquid undergoes reduction to generate citric acid.

[0047] Finally, the second water pump 701 is turned on to pump the citric acid into the crystallization kettle 3. Through the stirring of the third connecting rod 303 and the third scraper 304 and the heating of the second electric heating wire 501, the citric acid in the solution reaches the supersaturated state, so that the citric acid crystallizes out.

[0048] After use, the valves inside the first discharge pipe 105 and the second discharge pipe 205 are opened to discharge the waste liquid in the extraction tank 1 and the reduction tank 2. Then, the valve inside the third discharge pipe 305 is opened to discharge the citric acid.

[0049] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A citric acid waste liquid regeneration device, comprising an extraction tank (1), characterized in that: One side of the extraction tank (1) is fixedly installed with a reduction tank (2). One side of the reduction tank (2) away from the extraction tank (1) is fixedly installed with a crystallization kettle (3). A first feed pipe (6) is fixedly connected between the extraction tank (1) and the reduction tank (2). A second feed pipe (7) is fixedly connected between the reduction tank (2) and the crystallization kettle (3). A driving assembly (8) is installed at the bottom of the reduction tank (2). The extraction tank (1) includes a first feed inlet (101), a first rotating shaft (102), a first connecting rod (103), and a first scraper (104). The top of the extraction tank (1) is fixedly connected with the first feed inlet (101). The first rotating shaft (102) is movably installed inside the extraction tank (1). The outer wall of the first rotating shaft (102) is fixedly connected with the first connecting rod (103). The outer wall of the first connecting rod (103) is fixedly connected with the first scraper (104). The first scraper (104) is in contact with the inner wall of the extraction tank (1).

2. The citric acid waste liquid regeneration device according to claim 1, characterized in that: The reduction tank (2) includes a second feed inlet (201), a second rotating shaft (202), a second connecting rod (203), and a second scraper (204). The top of the reduction tank (2) is fixedly connected with the second feed inlet (201). The second rotating shaft (202) is movably installed inside the reduction tank (2). The outer wall of the second rotating shaft (202) is fixedly connected with the second connecting rod (203). The outer wall of the second connecting rod (203) is fixedly connected with the second scraper (204). The second scraper (204) is in contact with the inner wall of the reduction tank (2).

3. The citric acid waste liquid regeneration device according to claim 2, wherein: The crystallization kettle (3) includes a third feed inlet (301), a third rotating shaft (302), a third connecting rod (303), and a third scraper (304). The top of the crystallization kettle (3) is fixedly connected with the third feed inlet (301). The third rotating shaft (302) is movably installed inside the crystallization kettle (3). The outer wall of the third rotating shaft (302) is fixedly connected with the third connecting rod (303). The outer wall of the third connecting rod (303) is fixedly connected with the third scraper (304). The third scraper (304) is in contact with the inner wall of the crystallization kettle (3).

4. The citric acid waste liquid regeneration device according to claim 1, wherein: A first water pump (601) is fixedly installed on the first feed pipe (6). A first filter (602) is fixedly installed at the feed end of the first feed pipe (6). A second water pump (701) is fixedly installed on the second feed pipe (7). A second filter (702) is fixedly installed at the feed end of the second feed pipe (7).

5. The citric acid waste liquid regeneration device according to claim 1, wherein: The bottom of the extraction tank (1) is fixedly connected with a first discharge pipe (105). The bottom of the reduction tank (2) is fixedly connected with a second discharge pipe (205). The side wall of the crystallization kettle (3) is fixedly connected with a third discharge pipe (305). Valves are installed inside the first discharge pipe (105), the second discharge pipe (205), and the third discharge pipe (305).

6. The citric acid waste liquid regeneration device according to claim 2, characterized in that: The driving assembly (8) includes a one-way belt groove (801), a double-groove pulley (802), a support frame (803), a third protective cover (804), a driving motor (805) and a driving belt (806). One-way belt grooves (801) are fixedly connected to the bottoms of the first rotating shaft (102) and the third rotating shaft (302). A double-groove pulley (802) is fixedly connected to the bottom of the second rotating shaft (202). A support frame (803) is fixedly connected to the bottom of the reduction tank (2). A third protective cover (804) is fixedly connected inside the support frame (803). A driving motor (805) is fixedly installed inside the third protective cover (804). The bottom of the double-groove pulley (802) is fixedly installed at the output end of the driving motor (805). A driving belt (806) is fixedly installed between the one-way belt groove (801) and the double-groove pulley (802).

7. The citric acid waste liquid regeneration device according to claim 1, characterized in that: Mounting seats (9) are fixedly connected to the tops of the inner walls of the extraction tank (1), the reduction tank (2) and the crystallization kettle (3). Bearings (10) are fixedly installed inside the three mounting seats (9). The tops of the first rotating shaft (102), the second rotating shaft (202) and the third rotating shaft (302) are fixedly connected to the inner rings of the bearings (10).

8. The citric acid waste liquid regeneration device according to claim 1, wherein: A first protective cover (4) is fixedly installed on the outer wall of the extraction tank (1). A first electric heating wire (401) is fixedly installed between the first protective cover (4) and the extraction tank (1). A second protective cover (5) is fixedly installed on the outer wall of the crystallization kettle (3). A second electric heating wire (501) is fixedly installed between the crystallization kettle (3) and the second protective cover (5).

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