A dioxane treatment device

Abstract

The utility model relates to a dioxane treatment device, including the reactor one that has injected basic neutralization liquid, plate heat exchanger, flash tower, condenser, three -way pipe and reactor two, the reactor one is connected plate heat exchanger and flash tower in proper order through liquid pipe department, the gas outlet of flash tower is linked with condenser through the pipeline intercommunication, the liquid outlet of flash tower is connected with the first end of three -way pipe, the second end of three -way pipe is connected with the reactor one through material circulation extraction part, the third end of three -way pipe is connected with the reactor two through material delivery part, the utility model discloses through " neutralization preheating, flash evaporation azeotrope and circulating purification " three -level processing, let AES solution dioxane content from 20 30ppm drop to 5 8ppm, make downstream product safety significantly improve.

Description

Technical Field

[0001] This utility model relates to the field of chemical product purification technology, and in particular to a dioxane treatment device. Background Technology

[0002] Fatty alcohol ether sulfates are widely used in personal care, dishwashing, and various industrial applications due to their excellent surface activity and biodegradability. However, the sulfonation process of fatty alcohol ethers produces dioxane as a byproduct, which is classified as a Group 2B carcinogen by the International Agency for Research on Cancer (IARC). Therefore, both domestic and international standards have made clear regulations on the dioxane content in fatty alcohol ether sulfates. my country's industry standard requires that the dioxane content in fatty alcohol ether sulfates shall not exceed 70 ppm.

[0003] To control the dioxane content in fatty alcohol ether sulfate products, manufacturers typically employ the following methods: adjusting reaction conditions to make the sulfonation reaction milder, reducing the amount of dioxane generated, and using a post-removal method.

[0004] Currently, the dioxane content in commercially available fatty alcohol ether sulfate products is 20-30 ppm. However, some downstream companies have raised the requirements for dioxane levels to further improve product safety, hoping to achieve levels below 10 ppm. Commercially available fatty alcohol ether sulfates produced by conventional methods can no longer meet these requirements and also suffer from low efficiency. Utility Model Content

[0005] This utility model addresses the shortcomings of existing technologies by providing a dioxane treatment device, the specific technical solution of which is as follows: A dioxane treatment device includes a reactor one injected with an alkaline neutralization solution, a plate heat exchanger, a flash tower, a condenser, a three-way pipe, and a reactor two. The reactor one is connected to the plate heat exchanger and the flash tower in sequence through a liquid passage pipe. The outlet of the flash tower is connected to the condenser through a pipe. The outlet of the flash tower is connected to the first end of the three-way pipe. The second end of the three-way pipe is connected to the reactor one through a material circulation extraction section. The third end of the three-way pipe is connected to the reactor two through a material conveying section.

[0006] Preferably, it also includes a hot water circulation unit, which includes a hot water tank filled with water, the outlet of the hot water tank being connected to the inlet of the plate heat exchanger via an inlet pipe, a hot water circulation pump being installed on the inlet pipe, and the outlet of the plate heat exchanger being connected to the hot water tank via an outlet pipe.

[0007] Preferably, the liquid passage section includes a liquid outlet pipe one and a liquid outlet pipe two. One end of the liquid outlet pipe one is connected to a reactor one, and the other end of the liquid outlet pipe one is connected to the liquid inlet end of a plate heat exchanger. One end of the liquid outlet pipe two is connected to the liquid outlet end of a plate heat exchanger, and the other end of the liquid outlet pipe two is connected to the interior of a flash tower.

[0008] Preferably, the material circulation extraction unit includes a circulation pipe, on which a liquid circulation pump is installed. One end of the circulation pipe is connected to the second end of a three-way pipe, and the other end of the circulation pipe is connected to a reactor.

[0009] Preferably, the material conveying unit includes a conveying pipe, on which a conveying pump is installed. One end of the conveying pipe is connected to the third end of a three-way pipe, and the other end of the conveying pipe is connected to a second reactor. The second reactor is connected to an adjusting tank via a pipeline.

[0010] Preferably, valves are installed at the first, second, and third ends of the three-way pipe.

[0011] Preferably, temperature sensors are installed in the reactor, the hot water tank, and the flash tower.

[0012] Preferably, it also includes a vacuum pump, the input end of which is connected to the condenser via a pipe.

[0013] The beneficial effects of this utility model are: 1. Through a three-stage treatment process of "neutralization preheating, flash azeotropic distillation and circulation purification", the dioxane content in the AES solution is reduced from 20-30 ppm to 5-8 ppm, which significantly improves the safety of downstream products.

[0014] 2. By utilizing the heat of neutralization reaction, hot water circulation insulation, and waste heat recovery, the cost per ton of AES processing is reduced, resulting in cost savings for annual production capacity. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0016] Attached reference numerals: 1. Reactor 1; 100. Outlet pipe 1; 200. Outlet pipe 2; 2. Plate heat exchanger; 3. Hot water tank; 31. Inlet pipe; 310. Hot water circulation pump; 32. Outlet pipe; 4. Flash evaporator; 5. Condenser; 6. Vacuum pump; 7. T-connector; 8. Circulation pipe; 81. Liquid circulation pump; 9. Delivery pipe; 91. Delivery pump; 10. Reactor 2; 11. Adjustment tank. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0018] Example A dioxane treatment device, please refer to Figure 1 This utility model relates to the field of chemical product purification technology, and in particular to a dioxane treatment device, which is suitable for the removal of dioxane, a byproduct in the production of surfactants such as fatty alcohol ether sulfate (AES). Through a synergistic process of "neutralization reaction - waste heat utilization - flash azeotropic distillation - cyclic purification", the dioxane content in the product is reduced to below 10 ppm, meeting the high safety requirements of downstream applications, while improving processing efficiency and reducing energy consumption.

[0019] This device includes a neutralization reaction unit, a waste heat utilization unit, a flash evaporation removal unit, a condensation recovery unit, a circulation purification unit, and a subsequent adjustment unit. Each unit is linked to the pump body through pipelines to form a closed-loop processing flow of "reaction-heat exchange-removal-circulation-purification". The neutralization reaction unit includes reactor 1, which can neutralize the sulfonated crude AES and simultaneously use the heat of reaction to raise the material temperature, laying the foundation for subsequent flash evaporation. Reactor 1 is made of 304 stainless steel and has a double-layer stirring paddle (anchor type + paddle type combination to ensure uniform mixing of materials). The top of the reactor has a feed port (for introducing crude AES and alkaline neutralization liquid) and a reflux port (connected to circulation pipe 8), and the bottom has a liquid outlet (connected to liquid outlet pipe 100). Temperature sensors and pH sensors are installed on the inner wall to monitor the reaction status in real time.

[0020] During operation, the sulfonated crude AES containing dioxane (temperature 40-50℃, dioxane content 20-30ppm) and an alkaline neutralization solution (such as 10% NaOH solution, the flow rate is automatically adjusted according to the acidity of AES) are introduced into reactor 1. The neutralization reaction is carried out under stirring (H2SO4+2NaOH=Na2SO4+2H2O). The reaction is exothermic, which raises the material temperature to 70-80℃. The pH is controlled at 7.0-7.5 (to avoid excessive alkalinity that could lead to AES hydrolysis). The neutralized AES solution (solid content 30-35%) is transported to plate heat exchanger 2 through outlet pipe 100.

[0021] The neutralization reaction eliminates the acidity of the crude AES (preventing corrosion of subsequent equipment), while the heat of reaction raises the material temperature to the appropriate flash evaporation temperature, increasing the waste heat utilization rate to 90% and reducing heating energy consumption by 150 kWh per ton of product.

[0022] The liquid passage section includes a liquid outlet pipe 100, one end of which is connected to the liquid outlet flange at the bottom of reactor 1 (a fluororubber gasket is installed on the sealing surface, with a temperature resistance of -20~200℃), and the other end is connected to the liquid inlet of plate heat exchanger 2; a liquid circulation pump 81 (model ISG80-160) can be selectively installed on the pipe, which is started when the liquid level in reactor 1 exceeds 2 / 3 to ensure stable material delivery (avoiding stagnation).

[0023] The outlet pipe is a 200mm 304 stainless steel pipe of the same specification. One end is connected to the outlet end of the plate heat exchanger 2, and the other end extends into the flash tower 4 (the insertion depth is 1 / 3 of the height of the flash tower 4 to ensure uniform material distribution). A valve (electric ball valve, model Q941F-16) is installed on the pipeline and is controlled by linkage through temperature sensor signal (closed when the material temperature is below 70℃, and opened after the temperature rises).

[0024] The waste heat utilization unit maintains a stable material temperature through hot water circulation, while recovering excess heat to ensure flash evaporation efficiency. It includes a hot water tank 3 in the hot water circulation section, which is used to store hot water (initially filled with softened water to avoid scaling). An electric heating tube and a temperature sensor are installed inside the tank, and the outside is wrapped with a polyurethane insulation layer. The top of the tank has an inlet pipe 31 interface, and the bottom has an outlet pipe 32 interface.

[0025] Among them, the hot water circulation pump 310, model ISG65-160, is installed on the inlet pipe 31; one end of the inlet pipe 31 is connected to the outlet of the hot water tank 3, and the other end is connected to the inlet of the plate heat exchanger 2; one end of the outlet pipe 32 (same specification) is connected to the outlet of the plate heat exchanger 2, and the other end flows back to the hot water tank 3, forming a closed loop circulation.

[0026] Among them, plate heat exchanger 2 is used for heat exchange between material and hot water; the material goes through the "shell side" (AES solution) and the hot water goes through the "tube side". Temperature regulation is achieved through countercurrent heat exchange. When the material temperature is below 70°C, the hot water releases heat (from 85°C to 75°C) to heat the material; when the material temperature is above 80°C, the material releases heat to heat the hot water (recovering excess heat for subsequent conditioning tank insulation).

[0027] This maintains the AES solution temperature at 70-80℃, ensuring the azeotropic efficiency of dioxane and water during flash evaporation (azeotropic point 72℃, at which point the dioxane volatilization rate increases by 3 times); at the same time, excess heat is recovered, and the temperature of hot water tank 3 is maintained at 80-85℃, which can be used to adjust the insulation of the tank (reducing electric heating energy consumption), reducing the overall energy consumption per ton of product by 20%.

[0028] The flash evaporation removal unit achieves azeotropic separation of dioxane and AES solution through vacuum flash evaporation, which is a key step in the removal of dioxane. It includes a flash evaporation tower 4, with an outlet at the top (connected to the condenser 5), a liquid outlet at the bottom (connected to the three-way pipe 7), and a liquid inlet on the middle side (connected to the liquid outlet pipe 200). Temperature sensors (to monitor the temperature inside the tower and control it at 70-80℃) and pressure sensors (to monitor the vacuum level) are installed inside the tower.

[0029] The neutralized AES solution was evenly sprayed onto the packing surface through the outlet pipe 200. Under vacuum conditions (maintained by vacuum pump 6), the dioxane in the solution formed an azeotrope with water (dioxane content approximately 8.7%), which rapidly evaporated at 70-80℃ (evaporation rate 0.5 kg / h·m). 2 The dioxane-containing vapor is generated and discharged from the top outlet of the tower; the AES solution with dioxane removed (temporarily stored dioxane content 12-15ppm) flows down along the packing and collects at the bottom outlet of the tower, and is divided through the three-way pipe 7.

[0030] Vacuum flash evaporation lowers the azeotropic temperature (avoiding high-temperature decomposition of AES), and the packing increases the gas-liquid contact area, achieving a dioxane removal rate of 60-70% in a single pass, laying the foundation for subsequent cyclic purification. Stable pressure control within the column prevents excessively low vacuum from causing the solution to boil violently (affecting separation accuracy).

[0031] Among them, vacuum pump 6, model 2BV5121, is a water ring vacuum pump 6, which is connected to the gas outlet of condenser 5 through a pipeline; after vacuum pump 6 starts, it reduces the pressure inside flash tower 4 to -0.08~-0.09MPa, providing a vacuum environment for dioxane volatilization; at the same time, the sealing water (softened water) of vacuum pump 6 can recover some heat (heating to 40-50℃) for water replenishment of hot water tank 3 (further energy saving).

[0032] The condensation and recovery unit condenses the dioxane vapor generated by flash evaporation into liquid, avoiding tail gas emission pollution and simultaneously recovering dioxane. It includes a condenser 5, a shell-and-tube condenser 5, with dioxane-containing vapor (delivered from the outlet of flash tower 4) introduced into the shell side and industrial cooling water introduced into the tube side; the condenser 5 has an inlet at the top (connected to the outlet of flash tower 4), a liquid outlet at the bottom (connected to a dioxane collection tank with a volume of 50L), and cooling water inlet and outlet on the side.

[0033] Dioxane-containing vapor (temperature 70-80℃) enters the shell side of condenser 5, where it exchanges heat with the tube side cooling water, and the temperature drops to 30-40℃. It condenses into a dioxane-water mixture (dioxane concentration of about 10-15%), which flows into the collection tank through the bottom outlet. Non-condensable gases (such as air) are extracted by vacuum pump 6.

[0034] This avoids dioxane emissions with the tail gas (reducing environmental risks); the collected dioxane mixture can be further distilled and recovered to achieve resource reuse (such as as an industrial solvent), reducing hazardous waste treatment costs per month.

[0035] The circulating purification unit increases the residence time of the AES solution in the flash tower 4 by circulating materials, reducing the dioxane content to below 10ppm. It includes a circulating pipe 8 for the material circulation extraction section, one end of which is connected to the second flange of the three-way pipe 77, and the other end is connected to the reflux port at the top of the reactor 1. A liquid circulation pump 81 (81) (model ISG65-160) and a valve (same model electric ball valve) are installed on the pipe.

[0036] When the dioxane content of the AES solution at the bottom outlet of flash tower 4 exceeds 10 ppm (by the installed online detector), the controller opens the valve at the second end of the three-way pipe 7 and starts the liquid circulation pump 81 to transport the solution back to reactor 1 (to mix with fresh neutralized liquid), and then goes through the neutralization, heat exchange, and flash evaporation process again; the number of cycles is adjusted according to the dioxane content (usually 1-2 cycles are sufficient to meet the standard). After the standard is met, the circulation valve is closed and the delivery valve is opened.

[0037] The cyclic purification process increases the dioxane removal rate to over 95%, and the dioxane content in the final AES solution is stabilized at 5-8 ppm (far below the 10 ppm standard). At the same time, there is no stagnation of AES solution during the circulation process (circulation cycle ≤ 1 hour), which avoids product oxidation and deterioration (the color remains light yellow, and the retention rate of active ingredients is ≥ 98%).

[0038] The first end of the three-way pipe 7 is connected to the liquid outlet at the bottom of the flash tower 4, the second end is connected to the circulation pipe 8, and the third end is connected to the conveying pipe 9; all three ports are equipped with electric ball valves (with position feedback), which are controlled by the controller (the third end is closed during circulation, and the second end is closed during conveying), so there is no material leakage.

[0039] The subsequent adjustment unit adjusts the parameters of the qualified AES solution to ensure that it meets the downstream usage requirements. This includes the conveying pipe 9 of the material conveying section, which is connected to the third end of the tee pipe 7 at one end and to the top inlet of the reactor 2 10 at the other end. The pipe is equipped with a conveying pump 91 (model ISG80-125) and a filter to ensure the purity of the product during the conveying process.

[0040] Reactor 2 10 is equipped with an agitator for pH fine-tuning and defoaming of the AES solution; by adding a small amount of citric acid (0.1% concentration), the pH is adjusted from 7.0-7.5 to 6.5-7.0 (to better suit the needs of washing and care products), and at the same time, a defoamer (such as polyether, added at 50ppm) is added to eliminate foam (to prevent overflow during filling); the bottom of reactor 2 10 is connected to the adjustment tank 11 through a pipe.

[0041] The conditioning tank 11 is used for final homogenization and temporary storage of the product; a high-speed shear stirrer (1500 r / min speed to ensure uniform material) is installed inside the tank, and the temperature is maintained at 40-50℃ outside using the residual heat of the hot water tank 3 (through jacket heat exchange) (to prevent AES from solidifying); the conditioned AES product (dioxane content 5-8 ppm, solid content 30-35%, pH 6.5-7.0) is conveyed to the filling line through the bottom outlet of the tank.

[0042] Parameter adjustments ensure that AES products meet the usage standards of downstream enterprises (such as the requirements of pH and foam for personal care products), homogenization improves product stability (no stratification after 6 months of storage), and the temporary storage function ensures continuous operation of the production line (avoiding filling interruptions).

[0043] Workflow 1. Feeding and neutralization: AES crude product (25ppm dioxane) and NaOH solution are fed into reactor 1 in proportion, stirred and neutralized to pH 7.2, and the temperature is raised to 75℃. The solution is then transported to plate heat exchanger 2 through outlet pipe 100.

[0044] 2. Heat exchange and flash evaporation: Plate heat exchanger 2 uses hot water circulation to maintain the material temperature at 75°C, and sends it into flash tower 4 through outlet pipe 200; in flash tower 4, under a vacuum of -0.085MPa, dioxane and water azeotropically evaporate, and the steam is condensed and recovered by condenser 5 (the concentration of dioxane in the collection tank is 12%).

[0045] 3. Circulation and transport: The bottom solution (13ppm dioxane) of flash tower 4 enters circulation pipe 8 through three-way pipe 7 and is returned to reactor 1 for further treatment (7ppm after one circulation); after reaching the standard, switch three-way pipe 7 to transport pipe 9, and after fine adjustment of pH (6.8) and defoaming in reactor 2 10, it is sent to adjustment tank for homogenization and then filled.

[0046] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A dioxane treatment apparatus characterized by comprising: The reactor includes a first reactor (1) containing an alkaline neutralizing liquid, a plate heat exchanger (2), a flash tower (4), a condenser (5), a three-way pipe (7), and a second reactor (10). The first reactor (1) is connected to the plate heat exchanger (2) and the flash tower (4) in sequence through a liquid passage. The outlet of the flash tower (4) is connected to the condenser (5) through a pipe. The outlet of the flash tower (4) is connected to the first end of the three-way pipe (7). The second end of the three-way pipe (7) is connected to the first reactor (1) through a material circulation extraction section. The third end of the three-way pipe (7) is connected to the second reactor (10) through a material conveying section.

2. A dioxane treatment apparatus according to claim 1, wherein: It also includes a hot water circulation section, which includes a hot water tank (3) filled with water. The outlet of the hot water tank (3) is connected to the inlet of the plate heat exchanger (2) through an inlet pipe (31). A hot water circulation pump (310) is installed on the inlet pipe (31). The outlet of the plate heat exchanger (2) is connected to the hot water tank (3) through an outlet pipe (32).

3. A dioxane treatment apparatus according to claim 1, wherein: The liquid passage section includes a liquid outlet pipe one (100) and a liquid outlet pipe two (200). One end of the liquid outlet pipe one (100) is connected to the reactor one (1), and the other end of the liquid outlet pipe one (100) is connected to the liquid inlet of the plate heat exchanger (2). One end of the liquid outlet pipe two (200) is connected to the liquid outlet of the plate heat exchanger (2), and the other end of the liquid outlet pipe two (200) is connected to the inside of the flash tower (4).

4. A dioxane treatment apparatus according to claim 1, wherein: The material circulation extraction unit includes a circulation pipe (8), on which a liquid circulation pump (81) is installed. One end of the circulation pipe (8) is connected to the second end of a three-way pipe (7), and the other end of the circulation pipe (8) is connected to a reactor (1).

5. A dioxane treatment apparatus according to claim 1, wherein: The material conveying unit includes a conveying pipe (9), on which a conveying pump (91) is installed. One end of the conveying pipe (9) is connected to the third end of a three-way pipe (7), and the other end of the conveying pipe (9) is connected to reactor two (10). Reactor two (10) is connected to an adjusting tank (11) via a pipe.

6. A dioxane treatment apparatus according to claim 1, wherein: Valves are installed at the first, second and third ends of the three-way pipe (7).

7. A dioxane treatment apparatus according to claim 1, wherein: Temperature sensors are installed in reactor one (1), hot water tank (3) and flash tower (4), and a pH sensor is also installed in reactor one (1).

8. A dioxane treatment apparatus according to claim 1, wherein: It also includes a vacuum pump (6), the input end of which is connected to the condenser (5) via a pipe.

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