A method for treating organic peroxide initiator production wastewater by separating the organic phase

Abstract

The present invention discloses a treatment method for separating the organic phase from wastewater produced by an organic peroxide initiator, and belongs to the technical field of wastewater treatment. The present invention first classifies and collects the wastewater according to the different metal cations contained therein, and treats them separately, which is divided into potassium line pretreatment and sodium line pretreatment. The pretreatment process is to first perform neutralization and adjustment, and then enter the flotation machine for oil-water separation. The separated organic phase first enters the collection tank, and then enters the high-temperature decomposition tank for controllable decomposition treatment. The treated waste gas is sequentially subjected to demisting, UV photooxidation treatment, and activated carbon treatment before being discharged in compliance with the standards. The waste liquid from the high-temperature decomposition tank is returned to the waste oil collection tank and then enters the downstream treatment section of the mixing and regulating tank. The sodium line wastewater and the potassium line wastewater after separation and oil removal by the flotation machine enter evaporation pre-desalination respectively to obtain crude potassium chloride and crude sodium sulfate products, respectively. The present invention greatly reduces the load of the downstream device and improves the safety of the waste liquid treatment process. The device is simple and easy to implement industrially.

Description

Technical Field

[0001] The invention relates to the field of chemical industry, and in particular to a method for treating an organic phase of wastewater produced by an organic peroxide initiator. Background Art

[0002] Currently, the wastewater discharged from the organic peroxide initiator synthesis industry contains a large amount of organic phase containing peroxides, with extremely high COD (COD) levels of over 80,000 mg / L. This makes it difficult for conventional water treatment processes in general industries to meet these requirements. Furthermore, the presence of large amounts of peroxides in the wastewater creates significant safety risks during the wastewater treatment process. The temperature of the oily wastewater must not exceed 20°C throughout the entire treatment process. Therefore, oil separation must be performed at the front end to reduce the peroxide content in the water before subsequent wastewater treatment processes can proceed normally. However, the high-concentration peroxide waste oil separated during the current treatment process is extremely temperature-sensitive, making it highly dangerous and prone to decomposition, combustion, and explosion accidents. This presents a major challenge and pain point for the industry. For example, in 2017, a representative domestic peroxide manufacturer experienced a decomposition and combustion accident after the organic phase containing peroxides was enriched in its wastewater pool, resulting in significant losses. Currently, the industry is unable to carry out effective harmless on-site treatment. Usually, exhaust gas purification is used after incineration. This treatment method requires the waste liquid to be transported to a hazardous waste treatment station, which is extremely costly and also involves great risks in the collection, packaging and transportation processes.

[0003] Gansu Agricultural University previously disclosed a process for treating and recycling wastewater from the initiator CH335 (Patent Publication No. CN102173522A). This application collects wastewater directly from the outfall of a production facility. After stabilization, the risk of violent thermal decomposition of organic peroxides in the wastewater is essentially eliminated. Tertiary butyl alcohol, tertiary butyl peroxide, and sulfuric acid are then separated and recovered from the wastewater. However, the stabilization process described in this application has not been widely adopted. Summary of the Invention

[0004] 1. Technical problem to be solved by the invention

[0005] In view of the problems existing in the above-mentioned prior art, the present invention provides a method for separating the organic phase of organic peroxide initiator production wastewater; the present invention is a targeted pretreatment system for high-COD, high-salt, and high-peroxide wastewater generated in the synthesis process of organic peroxide initiators. First, the wastewater raw liquid is pretreated to separate the oil, and the organic phase containing peroxide enters a high-temperature controllable decomposition system for controllable decomposition treatment. The tail gas is directly purified and discharged in compliance with the standards. The organic phase content in the liquid wastewater after controlled decomposition and the wastewater after oil separation can be reduced to below 0.1%, and the evaporation treatment system of this system achieves efficient desalination and COD reduction effects.

[0006] 2. Technical solution

[0007] In order to achieve the above object, the technical solution provided by the present invention is:

[0008] The present invention provides a method for treating an organic peroxide initiator production wastewater by separating an organic phase, comprising the following steps:

[0009] (1) The workshop wastewater is discharged into the sodium line and potassium line wastewater collection tanks through the workshop trench according to the category, and then the wastewater is pumped to the neutralization tank by the raw water pump. 36% industrial hydrochloric acid is added to the potassium line neutralization tank at a flow rate of 5L / min, and the pH value is adjusted to 6-8 and then stopped. 98% industrial sulfuric acid is added to the sodium line neutralization tank at a flow rate of 5L / min, and the pH value is adjusted to 6-8 and then stopped.

[0010] (2) After the pH value is adjusted, the wastewater is pumped to the flotation machine at a wastewater feeding rate of 2 to 5 tons / hour. The oil floating on the surface of the wastewater entering the flotation machine is scraped into the waste oil collection tank by a scraper conveyor belt at a speed of 1 meter / minute. After scraping, the wastewater overflows into the primary desalination evaporation pre-storage tank, and the separated waste oil enters the waste oil treatment unit.

[0011] (3) The waste oil separated by sodium line and potassium line is mixed and discharged into the waste oil collection tank. The volume of the waste oil collection tank is 5m 3 The tank is equipped with a coil pipe to pass ethylene glycol for cooling, and the temperature in the tank is controlled between 3℃ and 15℃. The waste oil is then transported to the decomposition box through an explosion-proof gear pump for decomposition and disposal. The disposal volume each time is between 200L and 500L. Each time the waste oil content is tested in the decomposition box, when the active oxygen content is lower than 1.5%, the oil separation treatment is carried out normally. When the active oxygen content is higher than 1.5%, the waste water at the bottom of the spray tower is added for dilution and the detection index is lower than 1.5%, and then decomposition treatment is carried out. The waste oil decomposition box is sealed, and the glass window can observe the waste oil in the box. During the oil decomposition process, the box is equipped with a coil heat transfer oil to heat the waste oil. The top pipeline of the decomposition box is connected to the Venturi spray tower for demisting and spraying medium water. The waste water at the bottom of the tower is returned to the flotation machine for re-oil and water separation. The waste gas at the top of the tower is sequentially treated with UV light oxygen waste gas and activated carbon adsorption waste gas. After treatment, the waste gas meets the emission standards. During decomposition, the waste oil temperature is controlled below 60℃. Each decomposition lasts about 30 minutes. The decomposition process is observed through the window. When the waste oil in the decomposition box is heated to about 30℃, the spray tower is turned on for demisting. The initial spray water flow rate is 1-2m 3 / h, when the temperature rises to about 40℃, the peroxide enters the accelerated self-decomposition stage, and a large amount of visible smoke appears in the box. Adjust the spray water flow rate to 2-3m 3 / h, after observing that there is no visible smoke in the observation window, the spraying time is delayed for 5-6 minutes and then closed. The waste oil in the decomposition box is completely decomposed and cooled to room temperature and then flows back to the flotation machine for circulation and oil separation.

[0012] (4) After the flotation machine separates the oil, the wastewater overflows into the pre-evaporation storage tank and then enters the spiral plate heat exchanger. The steam inlet temperature of the spiral plate heat exchanger is 120℃±5℃, and the steam pressure is 0.3MPa. After heat exchange in the wastewater heat exchanger, the outlet water temperature rises to about 75℃, and then enters the evaporation tank. After evaporation, the salt crystals are precipitated at the bottom of the sedimentation tank. The crystallized salt discharge pipeline at the bottom of the tank is connected to the centrifuge for centrifugal salt removal. The centrifuged mother liquor water is returned to the evaporation tank for circulation. The steam coil in the evaporation tank is used for heating, and the wastewater temperature is controlled above 95℃. The top of the evaporation tank is connected to the steam condensation tank, and the air enters the bottom of the steam tank. The air inlet pipeline is equipped with a check valve. The coil in the tank is cooled by the circulating water at normal temperature. After the steam enters the tank, the condensed water condenses in the tank. The condensed condensed water is used as a heat exchange medium to condense the subsequent steam. An overflow port is provided in the middle of the condensation tank. Under normal continuous operation, the condensed water overflows into the mixing and regulating tank.

[0013] (5) The wastewater after pre-treatment after evaporation, the residual liquid wastewater after controlled decomposition and other conventional wastewater in the factory are mixed and sent into the equalization tank, and then the subsequent normal wastewater treatment operations are carried out after mixing.

[0014] 3. Beneficial effects

[0015] Compared with the existing known technologies, the technical solution provided by the present invention has the following significant effects:

[0016] (1) The present invention provides a method for separating the organic phase from wastewater produced by an organic peroxide initiator. The wastewater is classified and pretreated according to the different impurities contained in the wastewater to separate the organic phase and the aqueous phase. After separation, the low-oil content wastewater enters an evaporation treatment unit. After treatment, the COD of the effluent can be reduced from more than 100,000 mg / L to less than 6,000 mg / L, and the BOD can be reduced from less than 10,000 mg / L to less than 4,000 mg / L. The highly dangerous organic phase is collected and entered into a controllable decomposition device for controlled decomposition. After decomposition, the gas phase is subjected to a demister, UV light oxidation treatment, and activated carbon adsorption before being discharged in compliance with the discharge standards. After decomposition, the peroxide content in the liquid phase can be reduced to less than 0.1%.

[0017] (2) The present invention first collects and treats the wastewater generated during the synthesis of organic peroxide initiators according to the different metal cations contained, and divides it into potassium line pretreatment and sodium line pretreatment. The pretreatment process is to first neutralize and adjust, then enter the flotation machine for oil-water separation, the separated organic phase first enters the collection tank, and then enters the high-temperature decomposition tank for controllable decomposition treatment, the treated waste gas is demisted, UV photooxidation treated, and activated carbon treated in sequence before being discharged in compliance with the standards, the waste liquid from the high-temperature decomposition tank is returned to the waste oil collection tank and then enters the downstream treatment section of the mixing and regulating tank. The sodium line wastewater and potassium line wastewater after separation and oil removal by the flotation machine enter evaporation pre-desalting respectively to obtain crude potassium chloride and crude sodium sulfate products respectively. The waste liquid after potassium line and sodium line evaporation pretreatment and other conventional wastewater enter the mixing and regulating tank and enter the downstream wastewater treatment section, which greatly reduces the load of downstream equipment and improves the safety of the waste liquid treatment process. The device is simple and easy to implement industrially. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a treatment flow chart for separating the organic phase from organic peroxide initiator production wastewater according to the present invention. DETAILED DESCRIPTION

[0019] In order to further understand the content of the present invention, the present invention is described in detail with reference to the accompanying drawings and embodiments.

[0020] Example 1

[0021] Combine Figure 1 The present embodiment provides a method for separating the organic phase from organic peroxide initiator production wastewater, comprising the following steps:

[0022] (1) Sodium-containing wastewater and potassium-containing workshop wastewater are discharged into sodium-line and potassium-line wastewater collection pools respectively through workshop trenches according to their categories. Then, the wastewater is pumped to the neutralization pool through the raw water pump. 36% industrial hydrochloric acid is added to the sodium-line neutralization pool at a flow rate of 5 L / min, and the pH value is adjusted to 7 before the addition is stopped. 98% industrial sulfuric acid is added to the potassium-line neutralization pool at a flow rate of 5 L / min, and the pH value is adjusted to 7 before the addition is stopped.

[0023] (2) The wastewater from the pH adjustment tank is pumped to the flotation machine at a feed rate of 3 tons / hour. The oil floating on the surface of the wastewater entering the flotation machine is scraped into the waste oil collection tank by a scraper. The scraper conveyor belt speed is 1 meter / minute. After scraping, the wastewater overflows into the primary desalination and evaporation pre-storage tank, and the separated waste oil enters the waste oil treatment unit.

[0024] (3) The waste oil separated by the sodium line and potassium line is mixed and discharged into the waste oil collection tank. The temperature in the tank is controlled to drop to 12 ° C. The waste oil is then transported to the decomposition box for decomposition and disposal through an explosion-proof gear pump. 300L is transported. The active oxygen content of the waste oil is tested in the decomposition box and is 1.2%. The thermal oil furnace is turned on for heating and heating. When the waste oil in the decomposition box is heated to about 30 ° C, the spray tower is turned on for demisting. The initial spray water flow rate is 1m 3 / h, when the temperature rises to about 40℃, a lot of visible smoke appears in the observation box, and the spray water flow rate is adjusted to 2m 3 / h, after no visible smoke is observed in the observation window, the spraying time is delayed for 5 minutes and then closed. After the waste oil in the decomposition box is completely decomposed, it is cooled to room temperature and then refluxed into the mixing and regulating tank.

[0025] (4) After oil separation in the flotation machine, the wastewater overflows into the pre-evaporation storage tank. A submersible pump pumps the wastewater through a spiral plate heat exchanger and into the evaporation tank. Steam is turned on to heat the evaporation tank. The salt slurry at the bottom of the tank is pumped into a centrifuge for dehydration. The mother liquor is then returned to the evaporation tank for circulation. The wastewater temperature in the evaporation tank is 97°C. The steam enters the steam condenser, and after 2 hours, the condensate overflows from the overflow port into the mixing and regulating tank.

[0026] (5) The wastewater after evaporation pretreatment, the residual liquid wastewater after controlled decomposition and other conventional wastewater in the factory are mixed and sent into the equalization tank.

[0027] Example 2

[0028] (1) Sodium-containing wastewater and potassium-containing workshop wastewater are discharged into sodium-line and potassium-line wastewater collection pools respectively through workshop trenches according to their categories. Then, the wastewater is pumped to the neutralization pool through the raw water pump. 36% industrial hydrochloric acid is added to the sodium-line neutralization pool at a flow rate of 5 L / min, and the pH value is adjusted to 7 before the addition is stopped. 98% industrial sulfuric acid is added to the potassium-line neutralization pool at a flow rate of 5 L / min, and the pH value is adjusted to 7 before the addition is stopped.

[0029] (2) The wastewater from the pH adjustment tank is pumped to the flotation machine at a feed rate of 3 tons / hour. The oil floating on the surface of the wastewater entering the flotation machine is scraped into the waste oil collection tank by a scraper. The scraper conveyor belt speed is 1 meter / minute. After scraping, the wastewater overflows into the primary desalination and evaporation pre-storage tank, and the separated waste oil enters the waste oil treatment unit.

[0030] (3) The waste oil separated by the sodium line and potassium line is mixed and discharged into the waste oil collection tank. The temperature in the tank is controlled to drop to 12 ° C. The waste oil is then transported to the decomposition box for decomposition and disposal through an explosion-proof gear pump. 300L is transported. The active oxygen content of the waste oil is tested in the decomposition box and 1.5% is detected. The thermal oil furnace is turned on for heating and heating. When the waste oil in the decomposition box is heated to 30.1 ° C, the spray tower is turned on for demisting. The initial spray water flow rate is 1m 3 / h, when the temperature rises to 40.4℃, a lot of visible smoke appears in the observation box, and the spray water flow rate is adjusted to 2m 3 / h, after no visible smoke is observed in the observation window, the spraying time is delayed for 5 minutes and then closed. After the waste oil in the decomposition box is completely decomposed, it is cooled to room temperature and then refluxed into the mixing and regulating tank.

[0031] (4) After oil separation in the flotation machine, the wastewater overflows into the pre-evaporation storage tank. A submersible pump pumps the wastewater through a spiral plate heat exchanger and into the evaporation tank. Steam is turned on to heat the evaporation tank. The salt slurry at the bottom of the tank is pumped into a centrifuge for dehydration. The mother liquor is then returned to the evaporation tank for circulation. The wastewater temperature in the evaporation tank is 97°C. The steam enters the steam condenser, and after 2 hours, the condensate overflows from the overflow port into the mixing and regulating tank.

[0032] (5) The wastewater after evaporation pretreatment, the residual liquid wastewater after controlled decomposition and other conventional wastewater in the factory are mixed and sent into the equalization tank.

[0033] Example 3

[0034] (1) Sodium-containing wastewater and potassium-containing workshop wastewater are discharged into sodium-line and potassium-line wastewater collection pools respectively through workshop trenches according to their categories. Then, the wastewater is pumped to the neutralization pool through the raw water pump. 36% industrial hydrochloric acid is added to the sodium-line neutralization pool at a flow rate of 5 L / min, and the pH value is adjusted to 7 before the addition is stopped. 98% industrial sulfuric acid is added to the potassium-line neutralization pool at a flow rate of 5 L / min, and the pH value is adjusted to 7 before the addition is stopped.

[0035] (2) The wastewater from the pH adjustment tank is pumped to the flotation machine at a feed rate of 3 tons / hour. The oil floating on the surface of the wastewater entering the flotation machine is scraped into the waste oil collection tank by a scraper. The scraper conveyor belt speed is 1 meter / minute. After scraping, the wastewater overflows into the primary desalination and evaporation pre-storage tank, and the separated waste oil enters the waste oil treatment unit.

[0036] (3) The waste oil separated by the sodium line and potassium line is mixed and discharged into the waste oil collection tank. The temperature in the tank is controlled to drop to 12 ° C. The waste oil is then transported to the decomposition box for decomposition and disposal through an explosion-proof gear pump. 300L is transported. The active oxygen content of the waste oil is tested in the decomposition box and is 1.4%. The thermal oil furnace is turned on for heating and heating. When the waste oil in the decomposition box is heated to about 30.7 ° C, the spray tower is turned on for demisting. The initial spray water flow rate is 1m 3 / h, when the temperature rises to about 40.8℃, a lot of visible smoke appears in the observation box, and the spray water flow rate is adjusted to 2m 3 / h, after no visible smoke is observed in the observation window, the spraying time is delayed for 5 minutes and then closed. After the waste oil in the decomposition box is completely decomposed, it is cooled to room temperature and then refluxed into the mixing and regulating tank.

[0037] (4) After oil separation in the flotation machine, the wastewater overflows into the pre-evaporation storage tank. A submersible pump pumps the wastewater through a spiral plate heat exchanger and into the evaporation tank. Steam is turned on to heat the evaporation tank. The salt slurry at the bottom of the tank is pumped into a centrifuge for dehydration. The mother liquor is then returned to the evaporation tank for circulation. The wastewater temperature in the evaporation tank is 97°C. The steam enters the steam condenser, and after 2 hours, the condensate overflows from the overflow port into the mixing and regulating tank.

[0038] (5) The wastewater after evaporation pretreatment, the residual liquid wastewater after controlled decomposition and other conventional wastewater in the factory are mixed and sent into the equalization tank.

[0039] Comparative Example 1

[0040] Sodium-containing wastewater and potassium-containing workshop wastewater are directly discharged into the mixing and regulating tank for normal wastewater treatment operations.

[0041] Table 1: Comparison of water output data after evaporation

[0042]

[0043] The drainage of the embodiment meets the GB18918-2002 first-level water discharge standard

[0044] Table 2: Comparison of data before and after controlled decomposition of waste oil

[0045]

[0046] The exhaust gas discharged from the embodiment complies with the emission standard of GB16297-1996

[0047] The above is a schematic description of the present invention and its embodiments, which is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. Therefore, if a person skilled in the art is inspired by this and, without departing from the purpose of the present invention, designs a structure and embodiment similar to this technical solution without inventiveness, they shall fall within the scope of protection of the present invention.

Claims

1. A method for separating the organic phase from organic peroxide initiator production wastewater, characterized in that: The steps are: Step 1: The workshop wastewater is discharged into the sodium line wastewater collection pool and the potassium line wastewater collection pool through the workshop ditch according to the category, and then the wastewater is pumped to the potassium line neutralization pool and the sodium line neutralization pool respectively through the raw water pumping pump. Industrial hydrochloric acid is added to the potassium line neutralization pool, and industrial sulfuric acid is added to the sodium line neutralization pool; Step 2: The wastewater enters the potassium line flotation machine and the sodium line flotation machine respectively. The floating oil on the surface of the wastewater is scraped into the waste oil collection tank by the scraper. The scraped wastewater overflows into the pre-evaporation storage tank; Step 3: The waste oil discharged into the waste oil collection tank is transported to the decomposition box for decomposition and disposal. The decomposition box is equipped with a coil, and the heat transfer oil in the coil is used to heat the waste oil. The top pipeline of the decomposition box is connected to the Venturi spray tower. The Venturi spray tower sprays medium water for demisting. The waste water at the bottom of the tower is returned to the flotation machine for re-oil and water separation. The waste gas at the top of the tower is sequentially subjected to UV light oxygen waste gas treatment and activated carbon adsorption waste gas treatment. After treatment, the waste gas meets the discharge standards; the waste oil collection tank is equipped with a coil for cooling through ethylene glycol, and the temperature in the tank is controlled between 3°C and 15°C; during each decomposition and disposal process, the waste oil content is sampled and tested. When the active oxygen content is lower than 1.5%, the decomposition treatment is carried out normally. When the active oxygen content is higher than 1.5%, the waste water at the bottom of the spray tower is added for dilution and detection. If the index is lower than 1.5%, decomposition treatment is carried out; when the waste oil in the decomposition box is heated to 30°C, the spray tower is turned on for demisting, and the initial spray water flow rate is 1-2m 3 / h, when the temperature rises to 40℃, it enters the accelerated stage of peroxide self-decomposition, and the spray water flow rate is adjusted to 2-3m 3 / h, delay spraying for 5-6 minutes after no visible smoke, then shut down; Step 4: The wastewater overflowing into the pre-evaporation storage tank enters the spiral plate heat exchanger and then enters the evaporation tank. After evaporation, salt crystals are precipitated and settled at the bottom of the tank. The crystallized salt enters the centrifuge through the discharge pipeline for centrifugal salt removal, and the centrifuged mother liquor water is returned to the evaporation tank for circulation; the steam coil in the evaporation tank is heated, and the wastewater temperature is controlled above 95°C; the top of the evaporation tank is connected to the steam condenser, and air enters the bottom of the steam tank. A check valve is installed on the air inlet pipeline. The coil in the tank is usually cooled by air-cooled circulating water. After the steam enters the tank, the condensed water condenses in the tank. An overflow port is provided in the middle of the steam condenser. Under normal continuous operation, the condensed water overflows into the mixing and regulating tank; Step 5: The wastewater after evaporation pretreatment, the residual liquid wastewater after controlled decomposition and other conventional wastewater in the factory area enter the mixing and regulating tank, and after mixing, the subsequent normal wastewater treatment operation is carried out.

2. The method for treating organic peroxide initiator production wastewater by separating the organic phase according to claim 1, wherein: Step 1: Add 36% industrial hydrochloric acid by mass to the potassium line neutralization tank at a flow rate of 5 L / min, and stop adding when the pH value is adjusted to 6-8; add 98% industrial sulfuric acid by mass to the sodium line neutralization tank at a flow rate of 5 L / min, and stop adding when the pH value is adjusted to 6-8.

3. The method for treating organic peroxide initiator production wastewater by separating the organic phase according to claim 2, wherein: In step 4, the steam inlet temperature of the spiral plate heat exchanger is 120°C ± 5°C, the steam pressure is 0.3 MPa, and the outlet water temperature rises to 75°C after the wastewater heat exchange.

Images