A method for treating liquid waste from the bottom of heavy alcohol reactors based on molecular chain shearing oxidation.
By combining molecular chain shearing oxidation and the synergistic effect of oxidants, the problems of poor combustion performance of incineration and high temperature and high pressure of wet oxidation in the treatment of liquid waste from the bottom of heavy alcohol reactors have been solved. This has enabled effective degradation of COD under mild conditions, improving safety and treatment efficiency.
Patent Information
- Application Number
- CN202211037498.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-08-26
- Publication Date
- 2026-03-06
- Estimated Expiration
- 2042-08-26
AI Technical Summary
Existing technologies for treating liquid waste from the bottom of heavy alcohol reactors have limitations: incineration has poor combustion performance and is prone to clogging of the furnace nozzle, while wet oxidation requires high temperature and pressure, has high equipment requirements, and poses significant safety risks.
The molecular chain shearing oxidation method is adopted to degrade the liquid waste at the bottom of the heavy alcohol reactor through the synergistic effect of molecular chain shearing and oxidant. The reaction conditions are mild, and oxidants such as oxygen-enriched air, ozone-oxygen mixture, and potassium persulfate are used to control the reaction temperature, pressure and time. Sodium carbonate is added as a buffer to reduce the chemical oxygen demand (COD value).
It achieves a significant reduction in COD value under mild conditions, avoids the problem of burner clogging in incineration, and improves safety and treatment efficiency.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of organic liquid hazardous waste treatment, and in particular to a method for treating heavy alcohol bottom liquid waste based on molecular chain shear oxidation. Background Technology
[0002] Ethylene glycol is an important chemical raw material and the world's most consumed polyol. It can be used to manufacture PET, polyester, explosives, glyoxal, etc., and can also be used as an antifreeze, plasticizer, and solvent. Currently, the main synthetic routes for ethylene glycol can be divided into the ethylene process and the oxalate ester process, with the ethylene process being the most common.
[0003] This method uses ethylene and oxygen as the main raw materials. Under specific ratios, temperature, and pressure conditions, it produces gaseous ethylene oxide. Ethylene oxide and water are further hydrated in the liquid phase to produce ethylene glycol. During the production of ethylene glycol, the process produces diethylene glycol, triethylene glycol, and polyethylene glycol polycondensation products. These byproducts are collectively referred to as heavy alcohol bottom waste. The main characteristics of heavy alcohol bottom waste are poor combustibility and poor biodegradability, which have a certain impact on the aquatic environment, thus requiring treatment.
[0004] Currently, the main methods for treating this material both domestically and internationally are incineration and wet oxidation. Incineration is the most widely used and technologically mature method. However, because heavy alcohol liquid waste contains approximately 1% to 20% water, its combustion performance is poor, requiring additional fuel for incineration. Furthermore, after incineration, ungassed impurities accumulate in the burner nozzle, easily clogging it and causing damage to the incinerator. Wet oxidation involves diluting the heavy alcohol bottom liquid with water and reacting it for 3-4 hours under the influence of a precious metal catalyst, pure oxygen, high temperature (approximately 250°C), and high pressure (7.5 MPa) to completely oxidize the heavy alcohol-containing wastewater into low-COD wastewater. While this method is more effective, it requires harsh environments such as pure oxygen, high temperature, and high pressure, placing high demands on equipment and posing significant safety risks.
[0005] Therefore, in order to treat the liquid waste from the bottom of heavy alcohol reactors, it is necessary to develop a technical method that is mild and effective under existing technological conditions. Summary of the Invention
[0006] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a method for treating heavy alcohol bottom liquid waste based on molecular chain shearing oxidation. This method achieves the degradation of heavy alcohol and a significant reduction in the COD value of the reaction system through the synergistic effect of molecular chain shearing and oxidation of the heavy alcohol bottom liquid. The method has mild reaction conditions, strong operability, and good treatment effect.
[0007] The objective of this invention can be achieved through the following technical solution: a method for treating liquid waste from the bottom of a heavy alcohol reactor based on molecular chain shearing oxidation, the method comprising the following steps:
[0008] (1) Prepare a certain concentration of heavy alcohol dilution solution by mixing the viscous heavy alcohol bottom liquid waste, buffer, and water, stir evenly, and filter to obtain heavy alcohol reaction solution; In particular, when there are many solid impurities in the heavy alcohol bottom liquid waste, water can be used to prepare a certain concentration of dilution solution first, and then buffer can be added after filtration to obtain heavy alcohol reaction solution.
[0009] (2) Place the heavy alcohol reaction solution obtained in step (1) into the reactor, continuously add oxidant, and ensure that the content of oxidant in the heavy alcohol reaction solution is 10~200mg / L, the reaction time is 0.1~12 hours, the reaction temperature is 5~75℃, and the reaction pressure is 0.1~0.5Mpa.
[0010] Furthermore, the water content of the heavy alcohol bottom liquid waste is less than 10%, and the COD value is about 500,000~1,700,000 mg / L. Its main components are ethylene glycol and its polymers.
[0011] Furthermore, the composition of the liquid waste at the bottom of the heavy alcohol reactor includes ethylene glycol, diethylene glycol, triethylene glycol or tetraethylene glycol, as well as impurities such as chloride ions or iron filings.
[0012] Furthermore, the content of the heavy alcohol reaction solution in the heavy alcohol bottom liquid waste is 1~50wt%.
[0013] Furthermore, the buffer is sodium carbonate, and the amount added is 1 wt% of the heavy alcohol reaction solution.
[0014] Furthermore, the oxidant includes one or more of oxygen-enriched air, ozone-oxygen mixture, ozone-air mixture, potassium persulfate, sodium persulfate, and potassium permanganate.
[0015] Furthermore, the oxidant is any two of the following: oxygen-enriched air, ozone-oxygen mixture, ozone-air mixture, potassium persulfate, sodium persulfate, and potassium permanganate, mixed in a mass ratio of 1:(1.5-20).
[0016] Furthermore, the content of the oxidant in the heavy alcohol reaction solution is 50~180 mg / L, the reaction time is 1~8 hours, the reaction temperature is 15~65℃, and the reaction pressure is 0.1~0.3 MPa.
[0017] More preferably, the content of the oxidant in the heavy alcohol reaction solution is 80~155mg / L, the reaction time is 3~6 hours, the reaction temperature is 25~55℃, and the reaction pressure is 0.15~0.25Mpa.
[0018] The reduction rate of chemical oxygen demand (COD) of the system before and after the reaction is not less than 70%, preferably not less than 80%, and ideally not less than 85%.
[0019] Compared with the prior art, the present invention has the following beneficial effects:
[0020] (1) By adopting the technical solution of the present invention, the heavy alcohol liquid waste in the bottom of the ethylene glycol tower is converted into carbon dioxide, water and small molecule organic matter through molecular chain shearing oxidation technology, thereby reducing the difficulty of subsequent wastewater treatment.
[0021] (2) By adopting the technical solution of the present invention, the burner nozzle damage caused by the accumulation of impurities that cannot be gasified in the incineration method is avoided.
[0022] (3) The technical solution of the present invention has low reaction temperature and low reaction pressure, good treatment effect and high safety. Detailed Implementation
[0023] The embodiments of the present invention are described in detail below. These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operation processes. However, the scope of protection of the present invention is not limited to the following embodiments.
[0024] Example 1
[0025] A company's heavy alcohol bottom waste from the ethylene glycol production process has a COD of approximately 1,000,000 mg / L. This waste was diluted with water to a 1 wt% heavy alcohol solution. Na₂CO₃ was added to ensure a buffer content of 1 wt%. After thorough stirring and filtration, a heavy alcohol reaction solution was obtained. This solution was then placed in a reactor, with oxygen-enriched air continuously introduced to maintain an oxygen content of 80 mg / L. The reaction time was 3 hours, the pressure 0.1 MPa, and the temperature 75°C.
[0026] Example 2
[0027] A company's heavy alcohol bottom waste from the ethylene glycol production process has a COD of approximately 560,000 mg / L. This waste was diluted with water to a 1.5 wt% heavy alcohol solution. Na₂CO₃ was added to make the buffer content 1 wt%. After thorough stirring and filtration, a heavy alcohol reaction solution was obtained. This solution was then placed in a reactor, and an ozone-oxygen mixture was continuously introduced, maintaining the ozone concentration at 10 mg / L. The reaction time was 8 hours, the reaction pressure was 0.5 MPa, and the reaction temperature was 15°C.
[0028] Example 3
[0029] A company's ethylene glycol production process uses heavy alcohol bottom waste with a COD of approximately 720,000 mg / L. This waste is diluted with water to a 50% heavy alcohol solution. Na₂CO₃ is added as a buffer to maintain a buffer concentration of 1 wt%. After thorough stirring and filtration, a heavy alcohol reaction solution is obtained. This solution is then placed in a reactor, and potassium persulfate is continuously added, maintaining a potassium persulfate concentration of 50 mg / L. The reaction time is 1 hour, the reaction pressure is 0.15 MPa, and the reaction temperature is 5°C.
[0030] Example 4
[0031] A company's ethylene glycol production process uses heavy alcohol bottom waste with a COD of approximately 887,000 mg / L. This waste is diluted with water to a 25% heavy alcohol solution. Na₂CO₃ is added as a buffer to maintain a buffer concentration of 1 wt%. After thorough stirring and filtration, a heavy alcohol reaction solution is obtained. This solution is then placed in a reactor, and potassium permanganate is continuously added, maintaining a potassium permanganate concentration of 200 mg / L. The reaction time is 12 hours, the reaction pressure is 0.3 MPa, and the reaction temperature is 65°C.
[0032] Example 5
[0033] A company's heavy alcohol bottom waste from the ethylene glycol production process has a COD of approximately 1,100,000 mg / L. This waste was diluted with water to a 2 wt% heavy alcohol solution. Na₂CO₃ was added as a buffer to bring the buffer concentration to 1 wt%. After thorough stirring and filtration, a heavy alcohol reaction solution was obtained. This solution was then placed in a reactor, and an ozone-air mixture was continuously introduced, maintaining the ozone concentration in the liquid at 180 mg / L. The reaction time was 0.1 hours, the reaction pressure was 0.25 MPa, and the reaction temperature was 25°C.
[0034] Example 6
[0035] A company's heavy alcohol bottom waste from the ethylene glycol production process has a COD of approximately 554,000 mg / L. This waste was diluted with water to a 2 wt% heavy alcohol solution. Na₂CO₃ was added as a buffer to bring the buffer concentration to 1 wt%. After thorough stirring and filtration, a heavy alcohol reaction solution was obtained. This solution was then placed in a reactor, and an ozone-air mixture (0.1%–10% by weight) and sodium persulfate were continuously added at a mass ratio of 1:2. The concentration of the mixed oxidant in the liquid was controlled at 155 mg / L. The reaction time was 6 hours, the reaction pressure was 0.13 MPa, and the reaction temperature was 55°C.
[0036] Example 7
[0037] A company's ethylene glycol production process uses heavy alcohol bottom waste with a COD of approximately 1204000 mg / L. This waste is diluted with water to a 30 wt% heavy alcohol solution. Na₂CO₃ is added as a buffer to achieve a buffer concentration of 1 wt%. After thorough stirring and filtration, a heavy alcohol reaction solution is obtained. This solution is then placed in a reactor, where a 1:3 mass ratio of ozone-oxygen mixture and potassium persulfate is continuously added. The concentration of the mixed oxidant in the liquid is controlled at 90 mg / L. The reaction time is 0.5 hours, the reaction pressure is 0.35 MPa, and the reaction temperature is 60°C.
[0038] Example 8
[0039] A company's ethylene glycol production process uses heavy alcohol bottom waste with a COD of approximately 721,000 mg / L. This waste is diluted with water to a 4 wt% heavy alcohol solution. Na₂CO₃ is added as a buffer to bring the buffer concentration to 1 wt%. After thorough stirring and filtration, a heavy alcohol reaction solution is obtained. This solution is then placed in a reactor, and potassium persulfate and oxygen-enriched air are continuously added at a mass ratio of 1:20. The concentration of the mixed oxidant in the liquid is controlled at 20 mg / L. The reaction time is 4 hours, the reaction pressure is 0.4 MPa, and the reaction temperature is 10°C.
[0040] Example 9
[0041] A company's ethylene glycol production process uses heavy alcohol bottom waste with a COD of approximately 863,000 mg / L. This waste is diluted with water to a 10 wt% heavy alcohol solution. Na₂CO₃ is added as a buffer to bring the buffer concentration to 1 wt%. After thorough stirring and filtration, a heavy alcohol reaction solution is obtained. This solution is then placed in a reactor, and oxygen-enriched air (1:8 mass ratio of potassium permanganate and 30-40% oxygen by weight) is continuously added. The concentration of the mixed oxidant in the liquid is controlled at 140 mg / L. The reaction time is 10 hours, the reaction pressure is 0.1 MPa, and the reaction temperature is 35°C.
[0042] Example 10
[0043] A company's ethylene glycol production process uses heavy alcohol bottom waste liquid with a COD of approximately 101,000 mg / L. This waste liquid is diluted with water to a heavy alcohol concentration of 20 wt%. Na₂CO₃ is added as a buffer to bring the buffer concentration in the solution to 1 wt%. After thorough stirring, the solution is filtered to obtain a heavy alcohol reaction solution. This solution is then placed in a reactor, and potassium permanganate and potassium persulfate are continuously added in a 1:1 mass ratio. The concentration of the mixed oxidant in the liquid is controlled at 100 mg / L. The reaction time is 2 hours, the reaction pressure is 0.2 MPa, and the reaction temperature is 20°C.
[0044] Example 11
[0045] A company's ethylene glycol production process uses heavy alcohol bottom waste with a COD of approximately 700,000 mg / L. This waste is diluted with water to a 40 wt% heavy alcohol solution. Na₂CO₃ is added as a buffer to maintain a buffer concentration of 1 wt%. After thorough stirring and filtration, a heavy alcohol reaction solution is obtained. This solution is then placed in a reactor, where a 1:5 mass ratio of ozone-oxygen mixture and sodium persulfate is continuously added. The concentration of the mixed oxidant in the liquid is controlled at 35 mg / L. The reaction time is 4 hours, the reaction pressure is 0.2 MPa, and the reaction temperature is 35°C.
[0046] Example 12
[0047] A company's ethylene glycol production process uses heavy alcohol bottom waste with a COD of approximately 1,450,000 mg / L. This waste is diluted with water to a 3 wt% heavy alcohol solution. Na₂CO₃ is added as a buffer to bring the buffer concentration to 1 wt%. After thorough stirring and filtration, a heavy alcohol reaction solution is obtained. This solution is then placed in a reactor, and potassium permanganate is continuously added, maintaining a potassium permanganate concentration of 76 mg / L. The reaction time is 1.5 hours, the reaction pressure is 0.11 MPa, and the reaction temperature is 15°C.
[0048] Example 13
[0049] A company's ethylene glycol production process uses heavy alcohol bottom waste with a COD of approximately 649,000 mg / L. This waste is diluted with water to an 8 wt% heavy alcohol solution. Na₂CO₃ is added as a buffer to bring the buffer concentration to 1 wt%. After thorough stirring and filtration, a heavy alcohol reaction solution is obtained. This solution is then placed in a reactor, with oxygen-enriched air continuously introduced to maintain an oxygen content of 85 mg / L. The reaction time is 5 hours, the pressure is 0.5 MPa, and the temperature is 8°C.
[0050] Example 14
[0051] A company's ethylene glycol production process uses heavy alcohol bottom waste with a COD of approximately 860,000 mg / L. This waste is diluted with water to a 20 wt% heavy alcohol solution. Na₂CO₃ is added as a buffer to achieve a buffer concentration of 1 wt%. After thorough stirring and filtration, a heavy alcohol reaction solution is obtained. This solution is then placed in a reactor, and potassium permanganate and sodium persulfate are continuously added at a mass ratio of 1:10. The concentration of the mixed oxidant in the liquid is controlled at 195 mg / L. The reaction time is 11 hours, the reaction pressure is 0.1 MPa, and the reaction temperature is 40°C.
[0052] Example 15
[0053] A company's ethylene glycol production process uses heavy alcohol bottom waste with a COD of approximately 1,660,000 mg / L. This waste is diluted with water to a 4.5 wt% heavy alcohol solution. Na₂CO₃ is added as a buffer to bring the buffer concentration to 1 wt%. After thorough stirring and filtration, a heavy alcohol reaction solution is obtained. This solution is then placed in a reactor, and oxygen-enriched air (30-40% by weight) and potassium permanganate are continuously added at a mass ratio of 1:12. The concentration of the mixed oxidant in the liquid is controlled at 105 mg / L. The reaction time is 4 hours, the reaction pressure is 0.15 MPa, and the reaction temperature is 37°C.
[0054] Example 16
[0055] A company's ethylene glycol production process uses heavy alcohol bottom waste with a COD of approximately 1,410,000 mg / L. This waste is diluted with water to a 6 wt% heavy alcohol solution. Na₂CO₃ is added as a buffer to bring the buffer concentration to 1 wt%. After thorough stirring and filtration, a heavy alcohol reaction solution is obtained. This solution is then placed in a reactor, and an ozone-air mixture (1:5 mass ratio) and potassium persulfate (0.1%–10% by weight) are continuously added. The concentration of the mixed oxidant in the liquid is controlled at 63 mg / L. The reaction time is 3 hours, the reaction pressure is 0.1 MPa, and the reaction temperature is 30°C.
[0056] Example 17
[0057] A company's ethylene glycol production process uses heavy alcohol bottom waste with a COD of approximately 1,690,000 mg / L. This waste is diluted with water to a heavy alcohol concentration of 18 wt%. Na₂CO₃ is added as a buffer to bring the buffer concentration to 1 wt%. After thorough stirring and filtration, a heavy alcohol reaction solution is obtained. This solution is then placed in a reactor, and potassium persulfate and potassium permanganate are continuously added in a 1:7 mass ratio. The concentration of the mixed oxidant in the liquid is controlled at 46 mg / L. The reaction time is 7 hours, the reaction pressure is 0.45 MPa, and the reaction temperature is 70°C.
[0058] Comparative Example 1
[0059] A company's heavy alcohol bottom waste from the ethylene glycol production process has a COD of approximately 1,660,000 mg / L. This waste was diluted with water to a heavy alcohol concentration of 4.5 wt%, stirred thoroughly, and then filtered to obtain a heavy alcohol reaction solution. The reaction solution was then placed in a reactor, and oxygen-enriched air and potassium permanganate were continuously added at a mass ratio of 1:12. The concentration of the mixed oxidant in the liquid was controlled at 105 mg / L. The reaction time was 4 hours, the reaction pressure was 0.15 MPa, and the reaction temperature was 37°C.
[0060] Comparative Example 2
[0061] A company's heavy alcohol bottom waste from the ethylene glycol production process has a COD of approximately 560,000 mg / L. This waste was diluted with water to a 1.5 wt% heavy alcohol solution. Na₂CO₃ was added as a buffer to bring the buffer concentration to 1 wt%. After thorough stirring and filtration, a heavy alcohol reaction solution was obtained. This solution was then placed in a reactor, and an ozone-oxygen mixture was continuously introduced, maintaining the ozone concentration at 10 mg / L. The reaction time was 8 hours, the pressure 0.5 MPa, and the temperature 100°C.
[0062] Table 1 COD reduction rate in Examples 1-17
[0063]
[0064] Table 2 Comparison of COD removal rates between the comparative examples and the examples
[0065]
[0066] As can be seen from Table 1 above, the reduction rate of chemical oxygen demand (COD) value of the system before and after the reaction of the present invention is not less than 70%, and can reach up to 88%.
[0067] As can be seen from Table 2 above, comparing Example 15 and Comparative Example 1, under the same conditions, the COD reduction rate without a buffer is far less than that with a buffer. Comparing Example 2 and Comparative Example 2, under the same conditions, when the reaction temperature is higher than the protection range, the COD reduction rate is far less than that at the reaction temperature within the protection range.
Claims
1. A method for treating heavy alcohols still bottoms liquid waste based on the molecular chain scission oxidation process, characterized in that, The method comprises the following steps: (1) a heavy alcohol diluent is prepared by mixing viscous heavy alcohol still bottom liquid waste, a buffer and water, the content of the heavy alcohol still bottom liquid waste in the heavy alcohol reaction liquid is 1-50wt%, uniform stirring is performed, and a heavy alcohol reaction liquid is obtained after filtration; the water content of the heavy alcohol still bottom liquid waste is less than 10%, the COD value is 500000-1700000mg / L, and the main components of the heavy alcohol still bottom liquid waste are ethylene glycol and polymers thereof; the components of the heavy alcohol still bottom liquid waste include ethylene glycol, diethylene glycol, triethylene glycol or tetraethylene glycol, and chloride ions or iron scraps; the buffer is sodium carbonate, and the addition amount of the buffer is 1wt% of the heavy alcohol reaction liquid; (2) the heavy alcohol reaction liquid obtained in step (1) is placed in a reactor, an oxidizing agent is continuously added, the content of the oxidizing agent in the heavy alcohol reaction liquid is 10-200mg / L, the reaction time is 0.1-12 hours, the reaction temperature is 5-75℃, and the reaction pressure is 0.1-0.5MPa.
2. The method for treating heavy alcohol still bottom liquid waste based on molecular chain shearing oxidation method according to claim 1, characterized in that, The oxidizing agent includes one or more of the following: oxygen-rich air, ozone-oxygen mixed gas, ozone-air mixed gas, potassium persulfate, sodium persulfate and potassium permanganate.
3. The method of claim 2, wherein the method is characterized by, The oxidizing agent is a mixture of any two of the following: oxygen-rich air, ozone-oxygen mixed gas, ozone-air mixed gas, potassium persulfate, sodium persulfate and potassium permanganate, and the mass ratio is 1:(1.5-20).
4. The method for treating heavy alcohol still bottom liquid waste based on molecular chain shearing oxidation method according to claim 1, characterized in that, The content of the oxidizing agent in the heavy alcohol reaction liquid is 50-180mg / L, the reaction time is 1-8 hours, the reaction temperature is 15-65℃, and the reaction pressure is 0.1-0.3MPa.
5. The method for treating heavy alcohol still bottom liquid waste based on molecular chain shearing oxidation method according to claim 1 or 4, characterized in that, The content of the oxidizing agent in the heavy alcohol reaction liquid is 80-155mg / L, the reaction time is 3-6 hours, the reaction temperature is 25-55℃, and the reaction pressure is 0.15-0.25MPa.
6. The method of claim 1, wherein the method is characterized by, The reduction rate of the chemical oxygen demand (COD value) of the system before and after the reaction is not less than 70%.