System for reducing the cod in sodium sulfate in the production process of vitamin c

Abstract

This utility model discloses a system for reducing COD in sodium sulfate during vitamin C production, belonging to the field of vitamin production technology. The technical solution includes a controller and three interconnected pipelines: a primary sodium sulfate tank, a recycled sodium sulfate tank, and a mixed sodium sulfate tank. Liquid flow meters are installed on the pipelines between the primary and recycled sodium sulfate tanks, and between the primary and mixed sodium sulfate tanks. Pumps are installed on the pipelines between the primary and recycled sodium sulfate tanks, and between the primary and mixed sodium sulfate tanks. The liquid outlet of the mixed sodium sulfate tank is connected to the inlet of a centrifuge. A crystal washing pipeline is also installed on the upper part of the centrifuge, connected to an external water-containing methanol feed pipeline. The crystal washing pipeline is equipped with a crystal washing solvent pump, and a spray distribution device is installed at the end of the crystal washing pipeline near the centrifuge. This utility model solves the environmental problem of difficult sodium sulfate solid waste treatment.

Description

Technical Field

[0001] This utility model belongs to the field of vitamin production technology, specifically relating to a system for reducing COD in sodium sulfate during vitamin C production. Background Technology

[0002] The production process of vitamin C (Vc) is based on a two-step fermentation method, combined with chemical conversion and purification processes. The first fermentation uses sorbitol as a substrate and utilizes acid-producing bacteria (such as acetic acid bacteria) to convert it into sorbose. The second fermentation adopts a mixed bacterial fermentation system (co-operation of glucosinolate bacteria and Bacillus megaterium) to further convert sorbose into 2-keto-L-gulonic acid (2-KGA). After fermentation, the bacterial cells and residues are removed by plate and frame filtration and diatomaceous earth filtration to obtain a clear filtrate. Subsequently, 2-KGA was adsorbed using a strong acidic cation exchange resin and eluted with sodium hydroxide to obtain a high-concentration 2-KGA solution, providing raw materials for subsequent chemical conversion; and subsequent chemical conversion of 2-KGA into vitamin C; in the fourth step of chemical conversion, the conversion liquid generates a Vc solution and a sodium sulfate suspension through an acidification reaction. The sodium sulfate suspension is separated from the Vc solution and sodium sulfate solid by a pull-bag centrifuge (4). The Vc solution on the sodium sulfate is washed with aqueous methanol, but the sodium sulfate particles are small and have strong adhesion, making it difficult to remove. Some Vc is trapped with the sodium sulfate solid and needs to be repeatedly washed and recovered with aqueous methanol, but the washing effect is limited. The chemical oxygen demand (COD) in the mother liquor increases significantly (mainly from unseparated sodium sulfate, residual Vc and methanol), increasing the difficulty and cost of wastewater treatment. Utility Model Content

[0003] This invention provides a system for reducing COD in sodium sulfate during vitamin C production, thereby reducing the vitamin C content in sodium sulfate, increasing the yield of sodium sulfate, and solving the environmental problem of difficult solid waste disposal of sodium sulfate.

[0004] The technical solution of this utility model is as follows:

[0005] The system for reducing COD in sodium sulfate in the vitamin C production process includes a controller and a sodium sulfate liquid tank, a recycled sodium sulfate liquid tank, and a mixed sodium sulfate liquid tank connected by pipelines.

[0006] Liquid flow meters are installed in the pipelines between the genuine sodium sulfate tank and the recycled sodium sulfate tank, as well as between the genuine sodium sulfate tank and the mixed sodium sulfate tank. The liquid flow meters are electrically connected to the controller. Pumps are installed in the pipelines between the genuine sodium sulfate tank and the recycled sodium sulfate tank, as well as in the pipelines between the genuine sodium sulfate tank and the mixed sodium sulfate tank.

[0007] The liquid outlet of the mixed sodium sulfate tank is connected to the inlet of the centrifuge. A crystal washing pipeline is also installed on the upper part of the centrifuge. The crystal washing pipeline is connected to an external water-containing methanol feed pipeline. The crystal washing pipeline is equipped with a crystal washing solvent pump. A spray distribution device is installed at the end of the crystal washing pipeline near the centrifuge. The centrifuge is equipped with a solid material outlet and a liquid material outlet. The solid material outlet of the centrifuge is connected to the sodium sulfate solid outlet pipeline. The liquid material outlet of the centrifuge is connected to the washing liquid outlet pipeline and the mother liquor outlet pipeline, respectively. The washing liquid outlet pipeline is connected to the washing liquid tank, and the mother liquor outlet pipeline is connected to the mother liquor tank.

[0008] The top of the mixed sodium sulfate liquid tank is equipped with a stirring device, which includes a stirring motor located on the top of the mixed sodium sulfate liquid tank and a stirring shaft rotatably connected to the stirring motor. The stirring shaft extends into the tank, and a stirring paddle is provided on the side wall of the stirring shaft.

[0009] Preferably, the spray distribution device includes a three-way diverter valve connected to the end of the washing pipeline, the three-way diverter valve connecting to three branch pipelines, the three branch pipelines respectively connecting to distributor one, distributor two, and distributor three; each of the three branch pipelines is equipped with a liquid flow meter two, the liquid flow meter two being electrically connected to a controller; distributor one is located below the centrifuge inlet, distributor one is an annular stainless steel pipe, and several conical nozzles are uniformly welded to the bottom of the annular stainless steel pipe; distributor two is located in the middle of the centrifuge drum, distributor two is a cross-shaped stainless steel support, and fan-shaped atomizing nozzles are installed at the four ends of the cross-shaped stainless steel support; distributor three is located above the solid material outlet, distributor three is equipped with atomizing nozzles;

[0010] Preferably, the distributor is equipped with an electric heating tape, and the number of the conical nozzles is 20-30, with the nozzle orifice diameter being 1.5-2mm.

[0011] Preferably, the spray angle of the fan-shaped atomizing nozzle is 110°-120°, and the nozzle is tilted downward at 15°-20°.

[0012] Preferably, the crystal washing pipeline is equipped with a filter.

[0013] Preferably, the agitator has an anchor-type structure, and the gap between the outer edge of the agitator and the tank wall is ≤5mm.

[0014] Compared with the prior art, this utility model has the following advantages:

[0015] 1. This invention significantly reduces the COD (chemical oxygen demand) in sodium sulfate solid by optimizing the liquid-phase mixing, crystal washing solvent distribution, and centrifugal separation process of sodium sulfate, while improving the recovery rate of sodium sulfate.

[0016] 2. By measuring and mixing the flow rates of the genuine sodium sulfate solution tank and the recycled sodium sulfate solution tank, the concentration and impurity content of the sodium sulfate solution can be adjusted, preventing high COD recycled solution from directly entering the centrifugal separation stage.

[0017] 3. The stirring device (anchor-type stirring paddle) of the mixed sodium sulfate liquid tank ensures the uniformity of the liquid phase and reduces the problem of incomplete separation caused by excessively high local concentration.

[0018] 4. Multi-stage atomized crystal washing for efficient removal of residual vitamin C: The spray distribution device uses a three-way diverter valve to distribute the crystal washing solvent (containing water and methanol) to three distributors, achieving multi-stage spraying at the centrifuge inlet, the middle of the drum, and above the solid outlet: Distributor 1 pre-washes the surface of sodium sulfate particles during the feeding stage, removing large particles of residual vitamin C; the distributor's Twenty-shaped support and fan-shaped atomizing nozzles enhance the crystal washing effect in the middle of the drum, covering the movement trajectory of sodium sulfate particles and reducing blind spots in crystal washing; the top atomizing nozzle of distributor 3 performs a final wash before the solid is discharged, further reducing the amount of vitamin C entrained in the sodium sulfate.

[0019] 5. The centrifuge has separate outlets for washing liquid and mother liquor, which separate the washing liquid containing high concentrations of vitamin C from the mother liquor containing low concentrations of vitamin C for separate treatment, thereby reducing the total COD in the mother liquor tank and simplifying the subsequent wastewater treatment process. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of this utility model.

[0021] Figure 2 Schematic diagram of the mixed sodium sulfate liquid tank of this utility model

[0022] Figure 3 This is a schematic diagram of the structure of the distributor of this utility model.

[0023] Figure 4 This is a schematic diagram of the structure of the second distributor of this utility model.

[0024] In the diagram: 1. Genuine sodium sulfate solution tank; 2. Recycled sodium sulfate solution tank; 3. Mixed sodium sulfate solution tank; 301. Stirring motor; 302. Stirring shaft; 303. Stirring paddle; 4. Centrifuge; 5. Crystal washing pipeline; 6. Crystal washing solvent pump; 7. Solid material outlet; 8. Liquid material outlet; 9. Sodium sulfate solid outlet pipeline; 10. Washing solution outlet pipeline; 11. Mother liquor outlet pipeline; 12. Washing solution tank; 13. Mother liquor tank; 14. Three-way diverter valve; 15. Distributor 1; 16. Distributor 2; 17. Distributor 3. Detailed Implementation

[0025] To enable those skilled in the art to better understand the technical solutions of this utility model, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this utility model.

[0026] Example 1

[0027] like Figure 1-4 As shown, this embodiment provides a system for reducing COD in sodium sulfate during vitamin C production, including a controller and a standard sodium sulfate tank 1, a recycled sodium sulfate tank 2, and a mixed sodium sulfate tank 3 connected by pipelines.

[0028] Liquid flow meter 1 is installed in the pipeline between the genuine sodium sulfate tank 1 and the recycled sodium sulfate tank 2, as well as in the pipeline between the genuine sodium sulfate tank 1 and the mixed sodium sulfate tank 3. Liquid flow meter 1 is electrically connected to the controller. Pumps are installed in the pipeline between the genuine sodium sulfate tank 1 and the recycled sodium sulfate tank 2, as well as in the pipeline between the genuine sodium sulfate tank 1 and the mixed sodium sulfate tank 3.

[0029] The liquid outlet of the mixed sodium sulfate tank 3 is connected to the inlet of the centrifuge 4. A crystal washing pipeline 5 is also installed on the upper part of the centrifuge 4. The crystal washing pipeline 5 is connected to an external water-methanol feed pipeline. The crystal washing pipeline 5 is equipped with a crystal washing solvent pump 6 and a filter. A spray distribution device is installed at one end of the crystal washing pipeline 5 near the centrifuge 4. The spray distribution device includes a three-way diverter valve 14 connected to the end of the crystal washing pipeline 5. The three-way diverter valve 14 connects to three branch pipelines, which are respectively connected to distributor one 15, distributor two 16, and distributor three 17. Each of the three branch pipelines is equipped with a liquid flow meter two, which is electrically connected to a controller. Distributor one 15 is located below the inlet of the centrifuge 4. Distributor one 15 is an annular stainless steel pipe with an electric heating tape. Twenty conical nozzles with a 2mm orifice diameter are evenly welded to the bottom of the annular stainless steel pipe. Distributor two 16 is located in the middle of the centrifuge drum and is a cross-shaped stainless steel support. A cross-shaped stainless steel bracket has fan-shaped atomizing nozzles installed at its four ends; the spray angle of the fan-shaped atomizing nozzles is 120°, and the nozzles are tilted downwards at 20°; distributor 3 17 is set above the solid material outlet, and distributor 3 17 is equipped with atomizing nozzles; centrifuge 4 is equipped with a solid material outlet 7 and a liquid material outlet 8. The solid material outlet 7 of centrifuge 4 is connected to a sodium sulfate solid outlet pipe 9, and the liquid material outlet 8 of centrifuge 4 is connected to a washing liquid outlet pipe 10 and a mother liquor outlet pipe 11, respectively. The washing liquid outlet pipe 10 is connected to a washing liquid tank 12, and the mother liquor outlet pipe 11 is connected to a mother liquor tank 13; a stirring device is set on the top of the mixed sodium sulfate liquid tank 3. The stirring device includes a stirring motor 301 set on the top of the mixed sodium sulfate liquid tank 3 and a stirring shaft 302 rotatably connected to the stirring motor 301. The stirring shaft 302 extends into the tank, and a stirring paddle 303 is set on the side wall of the stirring shaft 302; the stirring paddle 303 has an anchor structure, and the gap between the outer edge of the stirring paddle 303 and the tank wall is ≤5mm.

[0030] Working process: Authentic sodium sulfate solution is pumped from Authentic Sodium Sulfate Solution Tank 1 into Mixed Sodium Sulfate Solution Tank 3 through pipeline; Recycled Sodium Sulfate Solution containing high COD impurities is pumped from Recycled Sodium Sulfate Solution Tank 2 into Mixed Sodium Sulfate Solution Tank 3 according to a preset ratio. The flow rates of the two lines are monitored by liquid flow meters corresponding to the pipelines and fed back to the controller to achieve precise proportioning; The stirring motor 301 of Mixed Sodium Sulfate Solution Tank 3 drives the stirring shaft 302 to rotate, and the anchor-type stirring paddle 303 uniformly mixes the liquid phase to avoid stratification or sedimentation. The mixed sodium sulfate solution enters the inlet of centrifuge 4 from the mixed sodium sulfate tank 3; the washing solvent, water-containing methanol, is transported through the washing pipeline 5 and distributed to three distributors via the three-way diverter valve 14: distributor one 15 sprays below the inlet to pre-wash the surface of sodium sulfate particles; distributor two 16 atomizes the middle of the drum to enhance the washing effect; distributor three 17 performs the final wash above the solid outlet to ensure that vitamin C residue is minimized; during the washing process, the electric heating tape maintains the temperature of the washing solvent, and the liquid flow meter two dynamically adjusts the flow rate of each branch pipeline. Centrifuge 4 rotates at high speed, and sodium sulfate solids are thrown to the inner wall of the drum and discharged through the solid material outlet 7 to the sodium sulfate solid outlet pipeline 9; the washing liquid (containing high concentration of vitamin C) enters the washing liquid tank 12 from the washing liquid outlet pipeline 10, where vitamin C can be recovered; the mother liquor (containing low concentration of vitamin C) enters the mother liquor tank 13 from the mother liquor outlet pipeline 11, significantly reducing COD and facilitating subsequent processing; the filter intercepts solid impurities in the washing pipeline 5 to prevent nozzle clogging.

[0031] Although the present invention has been described in detail with reference to the accompanying drawings and preferred embodiments, it is not limited thereto. Various equivalent modifications or substitutions can be made to the embodiments of the present invention by those skilled in the art without departing from the spirit and essence of the present invention, and all such modifications or substitutions should be within the scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A system for reducing COD in sodium sulfate during vitamin C production, characterized in that, Includes a controller and a genuine sodium sulfate solution tank (1), a recycled sodium sulfate solution tank (2), and a mixed sodium sulfate solution tank (3) connected by pipelines; Liquid flow meter 1 is installed in the pipeline between the genuine sodium sulfate tank (1) and the recycled sodium sulfate tank (2) and between the genuine sodium sulfate tank (1) and the mixed sodium sulfate tank (3). Liquid flow meter 1 is electrically connected to the controller. Pumps are installed in the pipeline between the genuine sodium sulfate tank (1) and the recycled sodium sulfate tank (2) and between the genuine sodium sulfate tank (1) and the mixed sodium sulfate tank (3). The liquid outlet of the mixed sodium sulfate tank (3) is connected to the inlet of the centrifuge (4). The centrifuge (4) is also equipped with a crystal washing pipeline (5). The crystal washing pipeline (5) is connected to the external water-carrying methanol feed pipeline. The crystal washing pipeline (5) is equipped with a crystal washing solvent pump (6). The end of the crystal washing pipeline (5) near the centrifuge (4) is equipped with a spray distribution device. The centrifuge (4) is equipped with a solid material outlet (7) and a liquid material outlet (8). The solid material outlet (7) of the centrifuge (4) is connected to the sodium sulfate solid outlet pipeline (9). The liquid material outlet (8) of the centrifuge (4) is connected to the washing liquid outlet pipeline (10) and the mother liquor outlet pipeline (11) respectively. The washing liquid outlet pipeline (10) is connected to the washing liquid tank (12). The mother liquor outlet pipeline (11) is connected to the mother liquor tank (13). A stirring device is provided on the top of the mixed sodium sulfate liquid tank (3). The stirring device includes a stirring motor (301) located on the top of the mixed sodium sulfate liquid tank (3) and a stirring shaft (302) rotatably connected to the stirring motor (301). The stirring shaft (302) extends into the tank, and a stirring paddle (303) is provided on the side wall of the stirring shaft (302).

2. The system for reducing COD in sodium sulfate during the vitamin C production process as described in claim 1, characterized in that, The spray distribution device includes a three-way diverter valve (14) connected to the end of the washing pipeline (5). The three-way diverter valve (14) is connected to three branch pipelines, which are respectively connected to distributor one (15), distributor two (16) and distributor three (17). Each of the three branch pipelines is equipped with a liquid flow meter two, which is electrically connected to the controller. Distributor one (15) is located below the feed inlet of the centrifuge (4). Distributor one (15) is an annular stainless steel pipe, and several conical nozzles are uniformly welded to the bottom of the annular stainless steel pipe. Distributor two (16) is located in the middle of the drum of the centrifuge (4). Distributor two (16) is a cross-shaped stainless steel bracket, and fan-shaped atomizing nozzles are installed at the four ends of the cross-shaped stainless steel bracket. Distributor three (17) is located above the solid material outlet, and atomizing nozzles are installed in distributor three (17).

3. The system for reducing COD in sodium sulfate during vitamin C production as described in claim 2, characterized in that, The distributor (15) is equipped with an electric heating tape, and the number of the conical nozzles is 20-30, with the orifice diameter of the conical nozzles being 1.5-2mm.

4. The system for reducing COD in sodium sulfate during the vitamin C production process as described in claim 2, characterized in that, The spray angle of the fan-shaped atomizing nozzle is 110°-120°, and the nozzle is tilted downwards at 15°-20°.

5. The system for reducing COD in sodium sulfate during the vitamin C production process as described in claim 1, characterized in that, The crystal washing pipeline (5) is equipped with a filter.

6. The system for reducing COD in sodium sulfate during the vitamin C production process as described in claim 1, characterized in that, The agitator (303) has an anchor structure, and the gap between the outer edge of the agitator (303) and the tank wall is ≤5mm.

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