MVR mother liquor resource utilization and biochemical treatment process and application

Abstract

The invention belongs to the field of environmental engineering, and particularly relates to an MVR mother liquor resource utilization and biochemical treatment process and application. The process comprises the following steps: adding 0.4-1.2% (less than or equal to 1.2%) of condensate into the mother liquor, adding 15-25% and 32% of caustic soda liquid for reaction, purging at 80-90 DEG C at 0.5-1.5 L / min until DMF is less than 0.1%, recovering amine, adjusting the pH value to be neutral, feeding into a biochemical system after the standard is detected, and gradually extracting the mother liquor proportion. The device is low in cost, free of pollution, capable of recycling resources and adaptive to existing equipment. The invention solves the problems of high cost, equipment corrosion, heavy pollution and no resource recovery in the traditional incineration treatment of MVR mother liquor (generated by concentrating sucralose production wastewater).

Description

Technical Field

[0001] This invention belongs to the field of environmental engineering, specifically relating to the resource utilization and biochemical treatment process and application of MVR mother liquor. Background Technology

[0002] In the production of sucralose, the wastewater discharged from the process needs to be concentrated by MVR (mechanical vapor recompression) and a single-effect system. This process generates MVR mother liquor, and the compliant treatment of this mother liquor is a key environmental and production challenge currently facing the industry.

[0003] Currently, the mainstream treatment process for MVR mother liquor in the industry is incineration. This process decomposes pollutants in the mother liquor through high-temperature incineration, but it has significant drawbacks in practical applications. On the one hand, incineration is expensive, not only because of the initial purchase cost of the incineration equipment, but also because certain components in the MVR mother liquor generate a large amount of acidic gases during incineration. These gases severely corrode the internal structure of the incinerator, significantly shortening its lifespan and significantly increasing the frequency and cost of maintenance and repair during equipment operation. On the other hand, improper handling of the acidic gases generated during incineration may also cause secondary environmental risks, failing to meet current stringent environmental regulations.

[0004] Against this backdrop, developing new methods for treating MVR mother liquor has significant practical implications and industry value. Research has revealed that anaerobic and aerobic microorganisms in wastewater treatment can be gradually cultivated and domesticated to adapt to high-salinity, high-chloride-content environments and metabolize normally. This provides a feasible basis for the biochemical treatment of MVR mother liquor. If a new process can be developed based on this, using appropriate alkaline hydrolysis to decompose and remove toxic substances such as DMF (dimethylformamide) from the mother liquor, preventing them from harming microorganisms, and then combining this with biochemical treatment to achieve harmless treatment of the mother liquor, it can not only solve the high cost and high corrosion problems of incineration processes, but also reduce technological upgrades by leveraging existing equipment. This will help companies reduce operating costs while meeting environmental protection requirements, and promote the improvement of green production levels in the sucralose industry. Therefore, the research and development of new treatment processes is both necessary and urgent. Summary of the Invention

[0005] To address the aforementioned shortcomings, this invention provides a process for the resource utilization and biochemical treatment of MVR mother liquor, which is lower in cost, free from equipment corrosion and secondary pollution compared to incineration, and can generate economic benefits and is easily industrialized and promoted based on existing equipment.

[0006] The technical solution of this invention is as follows: On the one hand, the present invention provides a process for the resource utilization and biochemical treatment of MVR mother liquor, including the following steps: (1) Alkaline hydrolysis stage: Take the MVR mother liquor and add it to the condensate at a mass ratio of 0.4%-1.2% to prepare the solution before alkaline hydrolysis; (2) Amine recovery stage: Add 15%-25% liquid alkali by mass to the solution obtained in step (1) before alkaline hydrolysis to carry out alkaline hydrolysis reaction. Then, heat the reaction system to 80-90℃ and purge at a flow rate of 0.5-1.5L / min. Stop purging when the DMF mass content is lower than 0.1%. Dimethylamine and ammonia are recovered during the process. (3) Control of influent to the biochemical system: Adjust the pH of the solution after the alkaline reaction in step (2) to neutral. When the chloride ion content is <1000ppm, the total salt content is <12000ppm, the total nitrogen content is <800ppm and the COD is <150000ppm, the treated solution that can enter the biochemical system is obtained. (4) Biochemical stage: The treatment liquid obtained in step (3) is introduced into the biochemical system. First, the treatment liquid with a low mass ratio of MVR mother liquor is added to the biochemical system. When the biochemical system is running stably and the ammonia nitrogen and COD in the drainage meet the emission requirements, the proportion of MVR mother liquor added in the treatment liquid is gradually increased. The control is based on the principle that the drainage of the biochemical system meets the emission indicators.

[0007] Specifically, in step (1), the mass ratio of MVR mother liquor to condensate can be 0.4%, 0.8%, or 1.2%.

[0008] Specifically, in step (2), the mass ratio of liquid alkali to the solution before alkali hydrolysis can be 15%, 20%, or 25%.

[0009] Specifically, the purging temperature in step (2) can be 80°C, 85°C or 90°C.

[0010] Specifically, the purging flow rate in step (2) can be 0.5 L / min, 1.0 L / min or 1.5 L / min.

[0011] Specifically, the mass concentration of the liquid alkali in step (2) can be 32%.

[0012] Specifically, in step (4), when gradually increasing the proportion of MVR mother liquor added to the treatment solution, the proportion of MVR mother liquor added is increased to 0.8% and 1.2% in turn.

[0013] Specifically, in step (4), the standard for the discharge of wastewater from the biochemical system is that the ammonia nitrogen in the wastewater is less than 500 ppm and the COD is less than 100 ppm.

[0014] Specifically, the MVR mother liquor can be generated from sucralose production wastewater after concentration and desalination by MVR and a single-effect system.

[0015] On another front, the present invention provides the application of the aforementioned process in the treatment of sucralose production wastewater.

[0016] The beneficial effects of this invention are as follows: (1) Compared with the incineration process, the technical solution provided by the present invention does not require the high maintenance cost of the incinerator, and the dimethylamine and ammonia can be recovered in the alkaline hydrolysis stage, creating additional economic benefits, which meets the enterprise's cost reduction needs.

[0017] (2) The technical solution of the present invention has no acid gas emission, avoiding equipment corrosion and air pollution; DMF can be reduced to below 0.1%; after alkaline hydrolysis, the key indicators of the solution (chloride ions, total salt, etc.) meet the requirements of biochemical influent; and the final effluent ammonia nitrogen and COD meet the standards, achieving harmless treatment.

[0018] (3) The technical solution of the present invention relies on existing equipment and does not require modification; by adjusting the parameters in a gradient, the process is stable and controllable, providing a reliable technical solution for enterprises of different sizes and is easy to promote. Detailed Implementation

[0019] The present invention will be further clearly and completely illustrated below through embodiments. These embodiments are only some examples of the present invention and are not intended to limit the present invention, but are only for illustrating the present invention. Unless otherwise specified, the experimental methods used in the following embodiments are all conventional experiments, and the materials and reagents used in the following embodiments are commercially available unless otherwise specified.

[0020] The technical solution of this invention is as follows: The wastewater discharged from the sucralose production process is concentrated and desalinated by the MVR and single-effect systems in the wastewater treatment plant. A certain amount of mother liquor is obtained from the resulting MVR mother liquor and then subjected to the following operations.

[0021] (1) Alkali hydrolysis stage: MVR mother liquor was added to the condensate at mass ratios (0.4%, 0.8%, 1.2%) to prepare a solution before alkali hydrolysis.

[0022] (2) Amine recovery stage: Add liquid alkali (32% mass concentration) at different mass ratios (15%, 20%, 25%) to the solution before alkali hydrolysis at different mass ratios (0.4%, 0.8%, 1.2%) of MVR mother liquor to carry out alkali hydrolysis reaction. Then raise the temperature to 80-90℃ and purge. The purging flow rate is 0.5L / min, 1.0L / min, and 1.5L / min. Stop when the DMF mass content in the solution is lower than 0.1%. The DMF detection method is carried out in accordance with DB34 / T 4300-2022.

[0023] (3) After alkaline hydrolysis, sulfuric acid is added to the solution to adjust the pH value to neutral. The chloride ion content, total salt content, total nitrogen content and COD in the solution are measured according to GB / T 5750.5-2023, HJ 51-2024, HJ 199-2023 and GB11914-89. Only when the measured value is less than the upper limit of the value that can be entered into the biochemical system can it be entered into the biochemical system for biochemical treatment.

[0024] (4) Biochemical stage: The alkaline hydrolysis solution is introduced into the biochemical system for treatment. First, the alkaline hydrolysis solution with an MVR mother liquor addition ratio of 0.4% by mass is added. The ammonia nitrogen and COD values ​​of the wastewater in the biochemical stage are observed to meet the discharge requirements. When the biochemical system is operating normally and stably and the wastewater indicators meet the expectations, the alkaline hydrolysis solution with an MVR mother liquor addition ratio of 0.8% by mass is added. The wastewater discharge of the biochemical system meets the indicators as the key point of inspection. Subsequently, the addition ratio of the alkaline hydrolysis solution with MVR mother liquor addition ratio is gradually increased.

[0025] The following are specific experimental examples: Example 1 A certain amount of mother liquor was obtained from the MVR mother liquor produced daily by the wastewater treatment plant and the following operations were performed.

[0026] (1) Alkali hydrolysis stage: MVR mother liquor is added to the condensate at a mass ratio of 0.4% to prepare a solution before alkali hydrolysis.

[0027] (2) Amine recovery stage: Add liquid alkali (32% mass concentration) at a mass ratio of 15% to the solution before alkaline hydrolysis to carry out alkaline hydrolysis reaction, then raise the temperature to 80°C and purge at a flow rate of 0.5 L / min. After 5 hours, the mass content of DMF in the solution is less than 0.1%, so the reaction is stopped.

[0028] (3) After alkaline hydrolysis, sulfuric acid is added to the solution to adjust the pH value to neutral. When the chloride ion content is less than 1000 ppm, the total salt content is less than 12000 ppm, the total nitrogen is less than 800 ppm, and the COD is less than 150000 ppm, it can enter the biochemical system for biochemical treatment. The chloride ion content in the solution is measured to be 620 ppm, the total salt content is 7800 ppm, the total nitrogen is 400 ppm, and the COD is 10080 ppm.

[0029] (4) Biochemical stage: The alkaline hydrolysis solution is introduced into the biochemical system for treatment. First, the alkaline hydrolysis solution with an MVR mother liquor addition ratio of 0.4% by mass is added. The ammonia nitrogen and COD values ​​of the wastewater in the biochemical stage are analyzed and tested to see if they meet the emission requirements. When the ammonia nitrogen in the wastewater of the biochemical system is less than 500 ppm and the COD is less than 100 ppm, the emission indicators meet the expectations. Then, the alkaline hydrolysis solution with an MVR mother liquor addition ratio of 0.8% by mass can be added. The key point to be examined is the compliance of the wastewater of the biochemical system with the emission indicators. The addition ratio of the alkaline hydrolysis solution with MVR mother liquor addition ratio is gradually increased in the future.

[0030] Example 2 A certain amount of mother liquor was obtained from the MVR mother liquor produced daily by the wastewater treatment plant and the following operations were performed.

[0031] (1) Alkali hydrolysis stage: MVR mother liquor is added to the condensate at a mass ratio of 0.8% to prepare a solution before alkali hydrolysis.

[0032] (2) Amine recovery stage: Add 20% liquid alkali (32% mass concentration) to the solution before alkaline hydrolysis to carry out alkaline hydrolysis reaction, then raise the temperature to 85°C and purge at a flow rate of 1.0 L / min. After 4 hours, the DMF mass content in the solution is less than 0.1%, so the reaction is stopped.

[0033] (3) After alkaline hydrolysis, sulfuric acid is added to the solution to adjust the pH value to neutral. When the chloride ion content is less than 1000 ppm, the salt content is less than 12000 ppm, the total nitrogen is less than 800 ppm, and the COD is less than 150000 ppm, it can enter the biochemical system for biochemical treatment. The chloride ion content in the solution is measured to be 780 ppm, the total salt content is 9180 ppm, the total nitrogen is 690 ppm, and the COD is 11480 ppm.

[0034] (4) Biochemical stage: The alkaline hydrolysis solution is introduced into the biochemical system for treatment. First, the alkaline hydrolysis solution with an MVR mother liquor addition ratio of 0.8% by mass is added. The ammonia nitrogen and COD values ​​of the wastewater in the biochemical stage are analyzed and tested to see if they meet the emission requirements. When the ammonia nitrogen in the wastewater of the biochemical system is less than 500 ppm and the COD is less than 100 ppm, the emission indicators meet the expectations. The alkaline hydrolysis solution with an MVR mother liquor addition ratio of 1.2% by mass can be added. The key point to be examined is the compliance of the wastewater of the biochemical system with the emission indicators. The addition ratio of the alkaline hydrolysis solution with MVR mother liquor addition ratio is gradually increased in the future.

[0035] Example 3 A certain amount of mother liquor was obtained from the MVR mother liquor produced daily by the wastewater treatment plant and the following operations were performed.

[0036] (1) Alkali hydrolysis stage: MVR mother liquor is added to the condensate at a mass ratio of 1.2% to prepare a solution before alkali hydrolysis.

[0037] (2) Amine recovery stage: Add liquid alkali (32% mass concentration) at a mass ratio of 25% to the solution before alkaline hydrolysis to carry out alkaline hydrolysis reaction, then heat to 90℃ and purge at a flow rate of 1.5L / min. After 6 hours, the mass content of DMF in the solution is less than 0.1%, so the reaction is stopped.

[0038] (3) After alkaline hydrolysis, sulfuric acid was added to the solution to adjust the pH value to neutral. When the chloride ion content is less than 1000 ppm, the total salt content is less than 12000 ppm, the total nitrogen is less than 800 ppm, and the COD is less than 150000 ppm, it can enter the biochemical system for biochemical treatment. The chloride ion content in the solution was measured to be 840, the total salt content was 11020 ppm, the total nitrogen was 746 ppm, and the COD was 13750 ppm.

[0039] (4) Biochemical stage: The alkaline hydrolysis solution is introduced into the biochemical system for treatment. First, the alkaline hydrolysis solution with an MVR mother liquor addition of 0.8% by mass is added. The ammonia nitrogen and COD values ​​of the wastewater in the biochemical stage are analyzed and tested to see if they meet the emission requirements. When the ammonia nitrogen in the wastewater of the biochemical system is less than 500 ppm and the COD is less than 100 ppm, the emission indicators meet the expectations. The compliance of the wastewater of the biochemical system with the emission indicators is the key point of examination. Subsequently, the addition of alkaline hydrolysis solution with an MVR mother liquor addition of mass ratio is gradually increased.

[0040] Comparative Example 1 A certain amount of mother liquor was obtained from the MVR mother liquor produced daily by the wastewater treatment plant and the following operations were performed.

[0041] (1) Alkali hydrolysis stage: MVR mother liquor is added to the condensate at a mass ratio of 0.4% to prepare a solution before alkali hydrolysis.

[0042] (2) Amine recovery stage: Add 15% liquid alkali (32% mass concentration) to the solution before alkaline hydrolysis to carry out alkaline hydrolysis reaction, then heat to 70℃ and purge, with a purge flow rate of 0.5L / min. Stop when the mass content of DMF in the solution is less than 0.1%. After about 5 hours, the mass content of DMF in the solution is 1.1%, and the value remains unchanged as time goes on.

[0043] Comparative Example 2 A certain amount of mother liquor was obtained from the MVR mother liquor produced daily by the wastewater treatment plant and the following operations were performed.

[0044] (1) Alkali hydrolysis stage: MVR mother liquor is added to the condensate at a mass ratio of 0.4% to prepare a solution before alkali hydrolysis.

[0045] (2) Amine recovery stage: Add 15% liquid alkali (32% mass concentration) to the solution before alkaline hydrolysis to carry out alkaline hydrolysis reaction, then heat to 80℃ and purge at a flow rate of 0.4L / min. Stop when the mass content of DMF in the solution is less than 0.1%. After about 4 hours, the mass content of DMF in the solution is 0.8%, and the value remains unchanged as time goes on.

[0046] Comparative Example 3 A certain amount of mother liquor was obtained from the MVR mother liquor produced daily by the wastewater treatment plant and the following operations were performed.

[0047] (1) Alkali hydrolysis stage: MVR mother liquor is added to the condensate at a mass ratio of 1.2% to prepare a solution before alkali hydrolysis.

[0048] (2) Amine recovery stage: Add 25% liquid alkali (32% mass concentration) to the solution before alkaline hydrolysis to carry out alkaline hydrolysis reaction, then heat to 70℃ and purge at a flow rate of 0.4L / min. After about 6 hours, the mass content of DMF in the solution is 2.3%, and the value remains unchanged as time goes on.

[0049] Comparative Example 4 A certain amount of mother liquor was obtained from the MVR mother liquor produced daily by the wastewater treatment plant and the following operations were performed.

[0050] (1) Alkali hydrolysis stage: MVR mother liquor is added to the condensate at a mass ratio of 1.3% to prepare a solution before alkali hydrolysis.

[0051] (2) Amine recovery stage: Add liquid alkali (32% mass concentration) at a mass ratio of 25% to the solution before alkaline hydrolysis to carry out alkaline hydrolysis reaction, then heat to 90℃ and purge at a flow rate of 1.5L / min. After 6 hours, the mass content of DMF in the solution is less than 0.1%, so the reaction is stopped.

[0052] (3) After alkaline hydrolysis, sulfuric acid was added to the solution to adjust the pH value to neutral. If the chloride ion content is less than 1000 ppm, the total salt content is less than 12000 ppm, the total nitrogen is less than 800 ppm, and the COD is less than 150000 ppm, then it can enter the biochemical system for biochemical treatment. The chloride ion content in the solution was measured to be 1121, the total salt content was 1440, the total nitrogen was 878 ppm and the COD was 16430 ppm, which did not meet the criteria for entering the biochemical system.

[0053] The above detailed description is a specific illustration of one feasible embodiment of the present invention, and this embodiment is not intended to limit the patent scope of the present invention. It should be noted that all equivalent implementations or modifications made without departing from the present invention should be included within the scope of the technical solution of the present invention. Therefore, the protection scope of the present invention should be determined by the appended claims.

Claims

1. A process for the resource utilization and biochemical treatment of MVR mother liquor, characterized in that, Includes the following steps: (1) Alkaline hydrolysis stage: Take the MVR mother liquor and add it to the condensate at a mass ratio of 0.4%-1.2% to prepare the solution before alkaline hydrolysis; (2) Amine recovery stage: Add 15%-25% liquid alkali by mass to the solution obtained in step (1) before alkaline hydrolysis to carry out alkaline hydrolysis reaction. Then, heat the reaction system to 80-90℃ and purge at a flow rate of 0.5-1.5L / min. Stop purging when the DMF mass content is lower than 0.1%. Dimethylamine and ammonia are recovered during the process. (3) Control of influent to the biochemical system: Adjust the pH of the solution after the alkaline reaction in step (2) to neutral. When the chloride ion content is <1000ppm, the total salt content is <12000ppm, the total nitrogen content is <800ppm and the COD is <150000ppm, the treated solution that can enter the biochemical system is obtained. (4) Biochemical stage: The treatment liquid obtained in step (3) is introduced into the biochemical system. First, the treatment liquid with a low mass ratio of MVR mother liquor is added to the biochemical system. When the biochemical system is running stably and the ammonia nitrogen and COD in the drainage meet the emission requirements, the proportion of MVR mother liquor added in the treatment liquid is gradually increased. The control is based on the principle that the drainage of the biochemical system meets the emission indicators.

2. The process according to claim 1, characterized in that, In step (1), the mass ratio of MVR mother liquor to condensate is 0.4%, 0.8%, or 1.2%.

3. The process according to claim 1, characterized in that, In step (2), the mass ratio of liquid alkali to the solution before alkali hydrolysis is 15%, 20%, or 25%.

4. The process according to claim 1, characterized in that, In step (2), the purging temperature is 80℃, 85℃ or 90℃.

5. The process according to claim 1, characterized in that, In step (2), the purging flow rate is 0.5 L / min, 1.0 L / min or 1.5 L / min.

6. The process according to claim 1, characterized in that, In step (2), the mass concentration of the liquid alkali is 32%.

7. The process according to claim 1, characterized in that, In step (4), when gradually increasing the proportion of MVR mother liquor added to the treatment solution, the proportion of MVR mother liquor added is increased to 0.8% and 1.2% in turn.

8. The process according to claim 1, characterized in that, In step (4), the standard for the discharge of wastewater from the biochemical system is that the ammonia nitrogen in the wastewater is less than 500 ppm and the COD is less than 100 ppm.

9. The process according to any one of claims 1-8, characterized in that, The MVR mother liquor is produced by concentrating and desalinating sucralose production wastewater through MVR and a single-effect system.

10. The application of the process according to any one of claims 1-9 in the treatment of sucralose production wastewater.