Process and device for preparing sodium alpha-olefin sulfonate through continuous sulfonation

Abstract

The invention discloses a process and a device for preparing sodium alpha-olefin sulfonate through continuous sulfonation. The process comprises the following steps: reacting alpha-olefin with SO3-containing gas in a multi-stage series falling-film sulfonator, and adjusting the feeding flow through online SO3 concentration detection and feedforward-feedback compound control; circularly curing the sulfonated intermediate for 60-120 minutes at the temperature of 40-70 DEG C; the materials are conveyed to a degassing-neutralizing integrated unit for vacuum degassing; quickly mixing the degassed material with alkali liquor through a mixer, neutralizing and hydrolyzing; bleaching and concentrating to obtain a finished product. The device comprises a multi-stage falling film sulfonator, a curing device, a degassing-neutralizing integrated unit, a tail gas condensation and absorption system and a post-treatment device. The randomness of manual operation is eliminated through automatic control, and the batch stability is improved; the integrated design shortens the high-temperature exposure time of the material and improves the color; and cyclic curing promotes conversion of sultone and reduces the content of residual sultone.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of sodium α-alkenyl sulfonate preparation, and particularly relates to a process and device for continuously preparing sodium α-alkenyl sulfonate through sulfonation. BACKGROUND

[0002] Sodium α-alkenyl sulfonate (AOS for short) is an important anionic surfactant, has good detergency, biodegradability and hard water adaptability, and is widely used in detergent, personal care product, textile auxiliary and other fields. With the continuous improvement of the quality requirements of the consumer market for products, how to stably produce high-quality sodium α-alkenyl sulfonate has become the focus of the industry.

[0003] The industrial production of sodium α-alkenyl sulfonate usually includes the processes of sulfonation, aging (maturation), neutralization, hydrolysis, bleaching and concentration. Among them, the sulfonation reaction is a key step, and gaseous SO3 is usually used for sulfonation of α-olefin to obtain a sulfonation intermediate. The intermediate contains sulfolactone, alkenyl sulfonic acid, sulfuric acid ester and other components, and the composition directly affects the performance and appearance of the final product.

[0004] In the traditional batch production process, the sulfonation reaction relies on manual sampling analysis of the SO3 concentration, and the feed amount is manually adjusted, so that the reaction conditions fluctuate. The consistency of the active content, color and other indicators of different batches of products needs to be improved, which to some extent affects the downstream formula design and product quality control.

[0005] The color of the sodium α-alkenyl sulfonate product is an important quality index, which directly affects its acceptance in high-end applications such as personal care. The sulfonation intermediate and alkenyl sulfonic acid are sensitive to temperature, and can easily decompose and oxidize under high temperature conditions to generate colored impurities. In the traditional process, the material after sulfonation needs to pass through multiple independent unit operations (aging tank, degassing tank, neutralization kettle, etc.), and the exposure time of the material in the high-temperature environment during the transportation and residence process between the equipment is relatively long, which may affect the color. Under normal circumstances, the color (APHA value) of the product before bleaching is between 120-160, and a large amount of bleaching agent needs to be used to reach the qualified standard, which increases the production cost and may introduce new impurities.

[0006] The sulfone lactone generated by the sulfonation reaction needs to be hydrolyzed under alkaline conditions to open the ring and be converted into sodium alkenyl sulfonate. If the sulfone lactone is not sufficiently hydrolyzed, it will remain in the final product, affecting the surface tension, wettability and other performance indicators of the product. In the traditional process, due to the difficulty in accurately controlling the residence time of the sulfonation intermediate in the aging and degassing stages, and the unstable composition of the material before neutralization, the alkaline hydrolysis reaction after neutralization may not be sufficient. Although the residual sulfone lactone can be reduced by prolonging the hydrolysis time, this will increase energy consumption and equipment investment, and is not conducive to color control. In addition, the traditional process uses independent unit equipment, such as independent aging tanks, degassing tanks, neutralization kettles, and hydrolysis kettles, which need to be connected by pipes, pumps, valves and other devices, resulting in a long process flow, large equipment footprint, and high investment cost. At the same time, the material transportation between independent devices requires additional energy consumption, and increases the complexity of operation and potential safety risks.

[0007] Therefore, the skilled person in the art proposes a process and device for preparing sodium α-alkenyl sulfonate by sulfonation. SUMMARY

[0008] Therefore, the skilled person in the art proposes a process and device for preparing sodium α-alkenyl sulfonate by sulfonation.

[0009] To achieve the above-mentioned purposes, the technical solution adopted by the present application is: A process for preparing sodium α-alkenyl sulfonate by continuous sulfonation, comprising the following steps: 1) continuously contacting α-olefin with SO3-containing gas in a multi-stage series falling film sulfonator, adjusting the SO3 feed flow and dilution air flow through online SO3 concentration detection and feedforward-feedback composite control, and increasing the reaction temperature of each stage of the sulfonator in turn to obtain a sulfonation intermediate; 2) aging the obtained sulfonation intermediate at a temperature of 40-70℃ for 60-120 minutes to convert the sulfone lactone into alkenyl sulfonic acid; 3) transporting the material of step 2) to a degassing-neutralization integrated unit and performing degassing treatment at an absolute pressure of 0.02-0.06 MPa and a temperature of 50-70℃; 4) rapidly mixing the degassed material of step 3) with lye through a mixer to achieve acid-base neutralization, and continuing to react the neutralized material at a temperature of 70-95℃ and a pH of 8.5-10.5 for 1-3 hours to complete the alkaline hydrolysis of the sulfone lactone and obtain a crude sodium α-alkenyl sulfonate solution; 5) bleaching and concentrating the obtained crude solution to obtain a finished sodium α-alkenyl sulfonate product.

[0010] Furthermore, the carbon chain length of the α-olefin is C 12 -C 18 The molar ratio of α-olefin to SO3 is 1:1.05-1.15; the volume fraction of SO3 in the SO3-containing gas is 2.0%-6.0%; the falling film sulfonator consists of 2-4 stages connected in series, with a total residence time of 30-90 seconds.

[0011] Further, the falling film sulfonator described in step 1) is a three-stage series sulfonator, with the residence time of each stage sulfonator allocated in a ratio of 1:1-2:1-2, and the temperature difference between two adjacent stages of sulfonator being 5-15℃; the reaction temperature of the first stage sulfonator is 30-40℃, the reaction temperature of the second stage sulfonator is 35-50℃, and the reaction temperature of the third stage sulfonator is 40-60℃.

[0012] Furthermore, in step 1), the feedforward channel of the feedforward-feedback composite control adjusts the dilution air flow rate according to the change in SO3 generation by the SO3 generator, and the feedback channel corrects the SO3 feed flow rate according to the SO3 volume fraction deviation detected online.

[0013] Furthermore, the maturation described in step 2) is carried out using a circulating maturation method, with the ratio of circulating flow rate to feed flow rate being 10-15:1.

[0014] Furthermore, the degassing time in step 3) is 10-20 seconds; steps 3) and 4) are completed continuously in the integrated unit, and the material is conveyed from the degassing chamber to the mixer through the short pipe, with the residence time of the material in the short pipe not exceeding 30 seconds.

[0015] Further, the mixing time in step 4) is 0.5-3 seconds, the alkaline solution is an aqueous sodium hydroxide solution with a concentration of 20%-40%, and the molar ratio of the alkaline solution to the sulfonation intermediate is 1.05-1.15:1.

[0016] An apparatus for the continuous sulfonation preparation of sodium α-olefin sulfonate according to the above process, the apparatus comprising a multi-stage falling film sulfonator (1), a curing device (2), a degassing-neutralization integrated unit (3), a tail gas condensation and absorption system (4), and a post-treatment device (5) connected in sequence by pipelines; the inlet of the multi-stage falling film sulfonator is provided with an online SO3 concentration detection device (6), which is signal-connected to a controller (7), and the controller adjusts the feed flow rate through a mass flow regulating valve (8) set on the SO3 feed pipeline and a mass flow regulating valve (9) set on the dilution air pipeline; The curing device includes a curing tank and a circulating pump. Part of the material from the outlet of the circulating pump is returned to the curing tank to form a cycle, and part of the material is transported to the degassing-neutralization integrated unit. The degassing-neutralization integrated unit includes a degassing chamber (10) and a neutralization reactor (11). The degassing chamber is equipped with a vacuum pumping system (12). The outlet of the degassing chamber is connected to the inlet of the neutralization reactor through a short pipe equipped with a mixer (13). The tail gas condensation and absorption system includes a tubular condenser (14) connected to the gas phase outlet of the degassing chamber and an alkaline absorption tower (15). The post-treatment device (5) includes a bleaching device and a concentration device.

[0017] Furthermore, the multi-stage falling film sulfonator is a series of 2-4 falling film sulfonation reactors, with each reactor having an independent temperature control system and liquid distributor, and the reactors at each stage being directly connected by short pipes; the online SO3 concentration detection device is a non-dispersive infrared analyzer or an ultraviolet absorption analyzer, which is equipped with a high-temperature sampling system, and the sampling pipeline is equipped with an electric heating or steam heating device; the controller adopts a feedforward-feedback composite control algorithm.

[0018] Furthermore, the integrated degassing-neutralization unit is a vertically oriented co-shell structure, with the degassing chamber located at the top and the neutralization reactor at the bottom, separated by a porous baffle or deflector. The baffle has an opening rate of 40%-55% and a pore size of 5-15 mm, forming a partially shared gas phase space. The short connecting pipe is a vertically or inclined circular pipe with an inner diameter of 80-150 mm and a length of 0.5-1.2 meters. The mixer is a tubular static mixer or a Venturi jet mixer. The neutralization reactor is equipped with a jacketed heating device and an online pH monitoring device. In the tail gas condensation and absorption system, the condensing medium is chilled brine or an ethylene glycol aqueous solution, and the condensation temperature is controlled between -5 and 5°C. The alkali absorption tower is a packed tower or a spray tower structure, with a packing layer height of 3-8 meters or a spray density of 20-50. The absorption liquid circulation tank is equipped with an online monitoring device for liquid level and concentration, with a capacity of m³ / (m²·h). The waste alkaline liquid after absorption contains sodium sulfate, which is concentrated and crystallized and then reused in the neutralization process of sodium fatty alcohol polyoxyethylene ether sulfate or sodium alkylbenzene sulfonate.

[0019] The beneficial effects of this invention are as follows: (1) Improved batch stability: The online SO3 concentration detection and feedforward-feedback composite control system is adopted to monitor and automatically adjust the SO3 feed flow rate in real time, eliminating the randomness of manual operation and ensuring a high degree of consistency of reaction conditions for each batch; the temperature gradient design of the multi-stage series sulfonators allows the reaction to proceed gradually within a controllable temperature range, avoiding local overheating or incomplete reaction.

[0020] (2) Color improvement: The integrated degassing-neutralization unit design allows the material to be directly transported from the degassing chamber to the neutralization reactor through a short pipe, which greatly shortens the exposure time of the material under high temperature conditions, effectively inhibits thermal decomposition and oxidation reaction, and reduces the generation of colored by-products; the maturation stage adopts a circulating maturation method, which achieves uniform temperature distribution through forced circulation and avoids local overheating.

[0021] (3) Residual sulfonyl lactones are reduced: the conversion of sulfonyl lactones to alkenyl sulfonic acid is promoted by cyclic ripening; rapid degassing reduces the fluctuation of material composition; the neutralization stage achieves rapid and uniform mixing of acid and base through a static mixer, creating stable reaction conditions for subsequent alkaline hydrolysis and ensuring that sulfonyl lactones are fully open-ring hydrolyzed. Attached Figure Description

[0022] Figure 1 This invention provides a schematic diagram of a continuous sulfonation process for preparing sodium α-olefin sulfonate; Figure 2 This is a schematic diagram of the apparatus for the continuous sulfonation preparation of sodium α-olefin sulfonate provided by the present invention; Figure 3 This is a schematic diagram of the integrated degassing-neutralization unit.

[0023] In the diagram: 1. Multi-stage falling film sulfonator; 2. Curing device; 3. Degassing-neutralization integrated unit; 4. Tail gas condensation and absorption system; 5. Post-treatment device; 6. Online SO3 concentration detection device; 7. Controller; 8. Mass flow regulating valve one; 9. Mass flow regulating valve two; 10. Degassing chamber; 11. Neutralization reactor; 12. Vacuum pumping system; 13. Mixer; 14. Tubular condenser; 15. Alkali absorption tower. Detailed Implementation

[0024] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0025] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0026] This invention provides a continuous sulfonation process for preparing sodium α-olefin sulfonate, which includes the following steps.

[0027] Step 1: The α-olefin is continuously reacted with SO3-containing gas in a multi-stage falling film sulfonator. The carbon chain length of the α-olefin is C. 12 -C 18 C is preferred. 14 -C 16 The molar ratio of α-olefin to SO3 is 1:1.05-1.15, with a slight excess of SO3 beneficial for improving the completeness of the sulfonation reaction. The volume fraction of SO3 in the SO3-containing gas is 2.0%-6.0%, preferably 3.0%-5.0%, and this gas is obtained by mixing high-concentration SO3 gas generated by an SO3 generator with diluted air.

[0028] The falling film sulfonator is a 2-4 stage series, preferably a 3-stage series, with a total residence time of 30-90 seconds. The multi-stage series design allows the sulfonation reaction to proceed in stages under different temperature conditions, which is beneficial for controlling the release of reaction heat and product distribution. When using a 3-stage series, the residence time of each sulfonator is distributed in a ratio of 1:1-2:1-2, and the reaction temperature of each sulfonator increases sequentially, with a temperature difference of 5-15℃ between adjacent stages. The reaction temperature of the first-stage sulfonator is 30-40℃, the second-stage sulfonator is 35-50℃, and the third-stage sulfonator is 40-60℃.

[0029] The feed flow rate is adjusted through online SO3 concentration detection and a feedforward-feedback composite control. The feedforward channel adjusts the dilution air flow rate based on changes in SO3 generation from the generator, while the feedback channel corrects the SO3 feed flow rate based on the online detection of SO3 volume fraction deviations. Feedforward control can quickly respond to fluctuations in SO3 generation, while feedback control can precisely correct SO3 concentration deviations. The combination of these two methods achieves precise SO3 concentration control, eliminating the randomness of traditional manual operation.

[0030] Step 2) The sulfonated intermediate obtained in Step 1) is aged at 40-70℃ for 60-120 minutes, preferably at 50-60℃ for 80-100 minutes. The aging process gradually converts the sulfonyl lactone in the sulfonated intermediate into alkenyl sulfonic acid, which is beneficial for the subsequent alkaline hydrolysis reaction. A circulating aging method is used, with a circulating flow rate to feed flow rate ratio of 10-15:1. The circulating aging process uses a circulating pump to circulate the material back into the aging tank, achieving thorough mixing and uniform temperature distribution, avoiding localized overheating that leads to color deepening, and shortening the material residence time distribution range, thus improving batch stability.

[0031] Step 3: The material obtained in Step 2) is conveyed to the integrated degassing-neutralization unit for degassing treatment under absolute pressure of 0.02-0.06 MPa and temperature of 50-70℃ for 10-20 seconds. The degassing treatment removes dissolved SO3 from the cooked material. Vacuum degassing prevents excessive foaming during subsequent neutralization. It is fast, effective, and quick, reducing the material's exposure time at high temperatures.

[0032] Steps 3) and 4) are completed continuously within the integrated unit. The material is conveyed from the degassing chamber to the mixer via a short connecting pipe, and the residence time of the material in the short connecting pipe does not exceed 30 seconds. The integrated design allows the degassed material to quickly enter the neutralization process, avoiding the long-distance transportation and long residence time between independent equipment in traditional processes. The exposure time of the material under high temperature conditions is shortened from 45-60 minutes in traditional processes to 15-20 minutes, significantly improving the product color.

[0033] Step 4: Quickly mix the degassed material from Step 3) with the alkaline solution using a mixer to achieve acid-base neutralization. The mixing time is 0.5-3 seconds. Rapid mixing ensures that the acid-base neutralization reaction is completed in a very short time, avoiding localized pH spikes or drops. The alkaline solution is an aqueous sodium hydroxide solution with a concentration of 20%-40%, and the molar ratio of alkaline solution to the sulfonation intermediate is 1.05-1.15:1. A slight excess of alkaline solution ensures complete neutralization of the acidic components in the sulfonation intermediate and provides a suitable pH environment for subsequent alkaline hydrolysis.

[0034] The neutralized material is then reacted for 1-3 hours at 70-95℃ and pH 8.5-10.5 to complete the alkaline hydrolysis of sulfonolactones. Alkaline hydrolysis causes the residual sulfonolactones to undergo ring-opening, converting them into sodium alkenyl sulfonate, thus increasing the active ingredient content and surface activity of the product. By optimizing the temperature and pH conditions, the product color can be controlled while ensuring complete hydrolysis of sulfonolactones.

[0035] Step 5: Bleaching and concentrating the obtained crude sodium α-alkenylsulfonate solution to obtain the finished sodium α-alkenylsulfonate product. Bleaching can further improve the product's color, and concentration can increase the content of active ingredients in the product.

[0036] The present invention also provides an apparatus for the continuous sulfonation preparation of sodium α-olefin sulfonate using the above-described process, such as... Figure 2 As shown, the device includes a multi-stage falling film sulfonator 1, a curing device 2, a degassing-neutralization integrated unit 3, a tail gas condensation and absorption system 4, and a post-treatment device 5, which are connected in sequence by pipelines. The multi-stage falling film sulfonator 1 is a series of 2-4 stages of falling film sulfonation reactors. Each stage of the reactor has an independent temperature control system and a liquid distributor, and the reactors at each stage are directly connected by short pipes. The independent temperature control system can adjust the temperature of each stage of the reactor to achieve temperature gradient control. The liquid distributor evenly distributes α-olefins on the inner wall surface of the reactor to form a uniform liquid film, thereby improving mass and heat transfer efficiency.

[0037] The inlet of the multi-stage falling film sulfonator is equipped with an online SO3 concentration detection device 6, which is a non-dispersive infrared analyzer or an ultraviolet absorption analyzer. The detection device is equipped with a high-temperature sampling system, and the sampling pipeline is equipped with an electric heating or steam heating device to maintain the temperature of the sampling probe at ≥180℃ to prevent SO3 from condensing during the sampling process.

[0038] The online SO3 concentration detection device is connected to the controller 7. The controller regulates the feed flow rate through the mass flow regulating valve 8 installed on the SO3 feed pipeline and the mass flow regulating valve 9 installed on the dilution air pipeline. The controller adopts a feedforward-feedback composite control algorithm. The feedforward channel is connected to the flow sensor signal of the SO3 generator, and the feedback channel is connected to the concentration signal of the online SO3 concentration detection device, so as to achieve rapid and stable control of SO3 concentration.

[0039] The specific implementation of the feedforward-feedback composite control algorithm is as follows: The feedforward control loop involves the controller acquiring the flow sensor signal from the SO3 generator in real time. When a change in SO3 generation is detected, the controller calculates the adjustment amount of the dilution air flow according to a preset proportional relationship and controls the dilution air flow regulating valve to adjust accordingly, so that the SO3 concentration in the mixed gas entering the sulfonator is maintained near the set value. The feedforward adjustment amount can be calculated according to the material balance relationship. The feedback control loop involves the controller comparing the online detected SO3 concentration with the set value to obtain the concentration deviation. The controller then uses a PID control algorithm (proportional-integral-derivative control) or a PI control algorithm (proportional-integral control) to calculate the correction amount of the SO3 feed flow and controls the SO3 feed flow regulating valve to fine-tune it, thereby eliminating the deviation of the feedforward control. The feedforward and feedback signals are fused through internal calculations in the controller and used together for the flow regulating valve, achieving a combination of fast response and precise control.

[0040] The curing unit 2 includes a curing tank and a circulating pump. Part of the material from the circulating pump outlet flows back to the curing tank to form a cycle, while the remaining material is transported to the degassing-neutralization integrated unit. The curing tank is equipped with a temperature control device and a liquid level detection device. The circulating pump is typically a screw pump, which has good conveying performance for high-viscosity materials. The ratio of the circulating flow rate to the feed flow rate is 10-15:1, and the circulating flow rate is controlled by adjusting the pump speed or a regulating valve on the circulating pipeline. The integrated degassing-neutralization unit 3 includes a degassing chamber 10 and a neutralization reactor 11. The degassing chamber is equipped with a vacuum extraction system 12, and the outlet of the degassing chamber is connected to the inlet of the neutralization reactor via a short connecting pipe equipped with a mixer 13. In a preferred embodiment, the integrated degassing-neutralization unit has a vertical common shell structure, with the degassing chamber located at the upper part and the neutralization reactor located at the lower part. A porous baffle or deflector is provided between the two, with an opening ratio of 40%-55% and a pore diameter of 5-15 mm, forming a partially shared gas phase space. This vertical arrangement utilizes gravity to allow the material to flow naturally downwards, reducing conveying equipment and energy consumption. The porous baffle serves both as support and separation, while also allowing the gas phase to flow to a certain extent, which is beneficial for pressure balance and gas discharge.

[0041] The vacuum pumping system includes a vacuum pump and a buffer tank. The vacuum pump maintains the absolute pressure in the degassing chamber at 0.02-0.06 MPa. The short connecting pipe is a vertically or inclined circular pipe with an inner diameter of 80-150 mm and a length of 0.5-1.2 meters. The design should ensure that the material residence time does not exceed 30 seconds. In a preferred embodiment, the inner wall of the short connecting pipe is provided with guide ribs or lined with polytetrafluoroethylene (PTFE). The guide ribs can promote the stability of material flow, and the PTFE lining has excellent corrosion resistance and low adhesion.

[0042] The mixer is either a tubular static mixer or a Venturi jet mixer. The tubular static mixer uses internal mixing elements to induce segmentation, shearing, and rotation of the material, achieving rapid and uniform mixing with a mixing time controllable between 0.5 and 3 seconds. The neutralization reactor is equipped with a jacketed heating device and an online pH monitoring device. The jacketed heating device can introduce steam or hot water to maintain the neutralized material at a hydrolysis reaction temperature of 70-95℃. The online pH monitoring device monitors the pH value of the material in real time, ensuring that the pH is maintained within the range of 8.5-10.5. The tail gas condensation and absorption system 4 includes a tubular condenser 14 connected to the gas phase outlet of the degassing chamber and an alkaline absorption tower 15. The gas discharged during the degassing process contains a small amount of SO3. Vapor, water vapor, and other pollutants need to be condensed and absorbed before being released. Tubular condensers are made of stainless steel or graphite, and the condensing medium is chilled brine or ethylene glycol solution. The condensation temperature is controlled between -5 and 5°C. Low-temperature condensation can effectively condense water vapor and some SO3.

[0043] The alkali absorption tower is a packed tower or spray tower structure, with a packing layer height of 3-8 meters or a spray density of 20-50 m³ / (m²·h). Gas enters the packed tower from the bottom, and alkali solution is sprayed from the top, creating a counter-current gas-liquid contact to achieve SO3 absorption. The absorption process is as follows: The absorption liquid circulation tank is equipped with online monitoring devices for liquid level and concentration. Liquid level monitoring controls the replenishment of the absorption liquid, and concentration monitoring determines the absorption capacity and replacement cycle of the absorption liquid.

[0044] The absorbed waste alkaline solution contains sodium sulfate, which, after concentration and crystallization, is reused in the neutralization process of sodium fatty alcohol polyoxyethylene ether sulfate or sodium alkylbenzene sulfonate. This resource utilization method reduces wastewater discharge, realizes the recycling of sulfur resources, and meets the requirements of clean production and circular economy. The post-processing unit 5 includes a bleaching device and a concentration device, used for bleaching and concentrating the crude sodium α-olefin sulfonate solution.

[0045] The working process of the device of the present invention is as follows: α-olefin and SO3-containing gas enter the multi-stage falling film sulfonator 1, the online SO3 concentration detection device 6 detects the SO3 concentration in real time, and the controller 7 adjusts the feed flow rate according to the detection result to achieve precise control of SO3 concentration; the material passes through each stage of sulfonator to complete the sulfonation reaction and then enters the curing device 2 for cyclic curing; the cured material enters the degassing-neutralization integrated unit 3, where vacuum degassing is performed in the degassing chamber 10, and the degassed material is rapidly mixed with alkaline solution through the short pipe and mixer 13 and then enters the neutralization reactor 11 to complete the alkaline hydrolysis reaction; the tail gas generated by degassing enters the tail gas condensation and absorption system 4 for treatment and then is discharged; the neutralized and hydrolyzed material enters the post-treatment device 5 for bleaching and concentration to obtain sodium α-olefin sulfonate product.

[0046] The detection methods for each indicator in the embodiment are as follows: (1) Active ingredient content: determined according to GB / T 5173-2018 Determination of anionic active ingredients in surfactants and detergents; (2) Color: The APHA value was determined according to the color determination method in GB / T 13173-2021 Test Methods for Surfactants and Detergents; (3) Residual sulfonyl lactone content: determined by gas chromatography; (4) Batch stability: After 10 consecutive batches of production, the coefficient of variation (CV) of active ingredient content and the standard deviation of color APHA value were calculated. Example 1

[0047] A continuous sulfonation process for preparing sodium α-olefin sulfonate includes the following steps: 1) Place C 14 α-olefins react continuously with SO3-containing gas (SO3 volume fraction 4.0%) in a three-stage series of falling film sulfonators. The α-olefin flow rate is 500 kg / h, and the molar ratio of α-olefin to SO3 is 1:1.10. The feed flow rates of SO3 and dilution air are adjusted using an online SO3 concentration detection device (non-dispersive infrared analyzer, sampling temperature 200℃) and a feedforward-feedback composite control system, keeping SO3 concentration fluctuations within ±0.2%. The residence times in the three sulfonators are allocated in a 1:1.5:1.5 ratio, with reaction temperatures of 35℃, 45℃, and 55℃ for each stage, and a total residence time of 60 seconds, yielding a sulfonated intermediate.

[0048] 2) The sulfonated intermediate was cyclically aged at 55°C for 90 minutes, with a circulation flow rate to feed flow rate ratio of 13:1, to convert sulfonyl lactone into alkenyl sulfonic acid.

[0049] 3) The matured material is transported to the degassing chamber of the degassing-neutralization integrated unit and degassed for 15 seconds under an absolute pressure of 0.04 MPa and a temperature of 60°C.

[0050] 4) The degassed material is rapidly mixed with 30% sodium hydroxide aqueous solution through a tubular static mixer via a short pipe (residence time 15 seconds) (mixing time 1.5 seconds). The molar ratio of alkali solution to sulfonation intermediate is 1.10:1. The neutralized material continues to react for 2 hours at 85℃ and pH 9.5 to complete the alkaline hydrolysis of sulfonyl lactone and obtain crude sodium α-alkenyl sulfonate.

[0051] 5) The crude liquid was bleached with hydrogen peroxide (0.20%), and then concentrated in a thin-film evaporator to an active content of 38% to obtain sodium α-olefin sulfonate. Example 2

[0052] Sodium α-alkenylsulfonate was prepared according to the method in Example 1, with the difference being: 1) Using C 12 The α-olefin has an SO3 volume fraction of 2.0% and a molar ratio of α-olefin to SO3 of 1:1.05. The residence time in the three-stage sulfonator is allocated in a 1:1:1 ratio, and the reaction temperatures of each stage of the sulfonator are 30℃, 35℃, and 40℃, respectively, with a total residence time of 30 seconds.

[0053] 2) The curing temperature is 40℃, the curing time is 60 minutes, and the ratio of circulation flow rate to feed flow rate is 10:1.

[0054] 3) Absolute pressure 0.06MPa, temperature 50℃, degassing time 10 seconds; material residence time in short pipe 20 seconds.

[0055] 4) The mixing time is 2 seconds, the alkali concentration is 20%, the molar ratio of alkali to sulfonation intermediate is 1.05:1, and the neutralized material is reacted at 70℃ and pH 8.5 for 3 hours.

[0056] 5) Bleaching agent (hydrogen peroxide) dosage: 0.28%. Example 3

[0057] Sodium α-alkenylsulfonate was prepared according to the method in Example 1, with the difference being: 1) Using C 18 The α-olefin has a SO3 volume fraction of 6.0% and a molar ratio of α-olefin to SO3 of 1:1.15. The residence time in the three-stage sulfonator is allocated in a 1:2:2 ratio, and the reaction temperatures of each stage of the sulfonator are 40℃, 50℃, and 60℃, respectively, with a total residence time of 90 seconds.

[0058] 2) The curing temperature is 70℃, the curing time is 120 minutes, and the ratio of circulating flow rate to feed flow rate is 15:1.

[0059] 3) Absolute pressure 0.02MPa, temperature 70℃, degassing time 20 seconds; material residence time in short pipe 25 seconds.

[0060] 4) The mixing time is 0.5 seconds, the alkali concentration is 40%, the molar ratio of alkali to sulfonation intermediate is 1.15:1, and the neutralized material is reacted at 95℃ and pH 10.5 for 1 hour.

[0061] 5) Bleaching agent (hydrogen peroxide) dosage: 0.25%.

[0062] Comparative Example 1 The specific steps for preparing sodium α-olefin sulfonate using a traditional batch process are as follows: (1) Sulfonation reaction: carried out in a single-stage falling film sulfonator, with manual sampling and analysis of SO3 concentration (sampling once every 30 minutes), and manual adjustment of the SO3 feed valve. C 14 The molar ratio of α-olefin to SO3 was 1:1.10, the volume fraction of SO3 was approximately 4% (fluctuation ±0.8%), the reaction temperature was 45℃, and the residence time was 60 seconds.

[0063] (2) Curing: The sulfonated intermediate is cured in a separate curing tank at 50°C for 90 minutes without circulating stirring.

[0064] (3) Degassing: The matured material is transported to an independent degassing tank (transport time is about 5 minutes) and degassed for 15 minutes under vacuum of 0.05 MPa and temperature of 60°C.

[0065] (4) Neutralization and hydrolysis: The degassed material is pumped into a separate neutralization vessel (transfer time is about 3 minutes), mixed with a 32% sodium hydroxide aqueous solution for neutralization (mixing time is about 10 minutes), and then hydrolyzed at 85°C and pH 9.5 for 2 hours. The material is exposed to high temperature for about 50 minutes from the end of sulfonation to the completion of neutralization.

[0066] (5) Post-treatment: Bleaching with hydrogen peroxide (0.35%) followed by concentration.

[0067] Comparative Example 2 Sodium α-alkenylsulfonate was prepared according to the method in Example 3, with the difference being: (1) Instead of using online SO3 concentration detection and feedforward-feedback composite control, manual periodic sampling and analysis are used for adjustment, with SO3 concentration fluctuations of ±0.6%.

[0068] (2) Instead of using an integrated degassing-neutralization unit, separate degassing tanks and neutralization kettles are used, and the material is exposed to high temperature for about 40 minutes.

[0069] (3) Instead of using a cycle of ripening, let it sit to ripen.

[0070] Table 1. Comparison of product performance between various embodiments and comparative examples

[0071] Note: CV is the coefficient of variation; standard deviations are based on data from 10 consecutive batches.

[0072] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A continuous sulfonation process for preparing sodium α-alkenyl sulfonate, comprising the following steps: 1) α-olefins are continuously reacted with SO3-containing gas in a multi-stage series falling film sulfonator. The SO3 feed flow rate and dilution air flow rate are adjusted by online SO3 concentration detection and feedforward-feedback composite control. The reaction temperature of each stage of the sulfonator increases sequentially to obtain the sulfonated intermediate. 2) The obtained sulfonated intermediate is aged at 40-70℃ for 60-120 minutes to convert sulfonyl lactone into alkenyl sulfonic acid; 3) The material from step 2) is conveyed to the degassing-neutralization integrated unit and degassed under absolute pressure of 0.02-0.06MPa and temperature of 50-70℃. 4) The degassed material from step 3) is rapidly mixed with alkaline solution through a mixer to achieve acid-base neutralization. The neutralized material is then reacted for 1-3 hours at a temperature of 70-95℃ and a pH of 8.5-10.5 to complete the alkaline hydrolysis of sulfonyl lactone and obtain crude sodium α-alkenyl sulfonate. 5) The obtained crude liquid is bleached and concentrated to obtain sodium α-olefin sulfonate product.

2. The process according to claim 1, characterized in that: The carbon chain length of the α-olefin is C. 12 -C 18 The molar ratio of α-olefin to SO3 is 1:1.05-1.15; the volume fraction of SO3 in the SO3-containing gas is 2.0%-6.0%; the falling film sulfonator consists of 2-4 stages connected in series, with a total residence time of 30-90 seconds.

3. The process according to claim 2, characterized in that: The falling film sulfonator described in step 1) is a three-stage series sulfonator. The residence time of each stage of the sulfonator is distributed in a ratio of 1:1-2:1-2. The temperature difference between two adjacent stages of the sulfonator is 5-15℃. The reaction temperature of the first stage sulfonator is 30-40℃, the reaction temperature of the second stage sulfonator is 35-50℃, and the reaction temperature of the third stage sulfonator is 40-60℃.

4. The process according to claim 1, characterized in that: In step 1), the feedforward channel of the feedforward-feedback composite control adjusts the dilution air flow rate according to the change in SO3 generation from the SO3 generator, and the feedback channel corrects the SO3 feed flow rate based on the deviation of SO3 volume fraction detected online.

5. The process according to claim 1, characterized in that: The maturation described in step 2) is carried out using a circulating maturation method, with the ratio of circulating flow rate to feed flow rate being 10-15:

1.

6. The process according to claim 1, characterized in that: The degassing time in step 3) is 10-20 seconds; steps 3) and 4) are completed continuously in the integrated unit, and the material is conveyed from the degassing chamber to the mixer through the short pipe, and the residence time of the material in the short pipe does not exceed 30 seconds.

7. The process according to claim 1, characterized in that: The mixing time in step 4) is 0.5-3 seconds, the alkali solution is an aqueous solution of sodium hydroxide with a concentration of 20%-40%, and the molar ratio of alkali solution to sulfonation intermediate is 1.05-1.15:

1.

8. An apparatus for the continuous sulfonation preparation of sodium α-alkenylsulfonate, characterized in that, The device includes a multi-stage falling film sulfonator (1), a curing device (2), a degassing-neutralization integrated unit (3), a tail gas condensation and absorption system (4), and a post-treatment device (5) connected in sequence by pipelines. The inlet of the multi-stage falling film sulfonator is equipped with an online SO3 concentration detection device (6), which is signal-connected to a controller (7). The controller regulates the feed flow rate through a mass flow regulating valve (8) installed on the SO3 feed pipeline and a mass flow regulating valve (9) installed on the dilution air pipeline. The curing device includes a curing tank and a circulating water system. The circulating pump returns part of the material from the outlet to the maturation tank to form a cycle, and the other part is transported to the degassing-neutralization integrated unit. The degassing-neutralization integrated unit includes a degassing chamber (10) and a neutralization reactor (11). The degassing chamber is equipped with a vacuum pumping system (12). The outlet of the degassing chamber is connected to the inlet of the neutralization reactor through a short pipe equipped with a mixer (13). The tail gas condensation and absorption system includes a tubular condenser (14) connected to the gas phase outlet of the degassing chamber and an alkaline absorption tower (15). The post-treatment device (5) includes a bleaching device and a concentration device.

9. The apparatus according to claim 8, characterized in that: The multi-stage falling film sulfonator is a series of 2-4 falling film sulfonation reactors, with each reactor having an independent temperature control system and liquid distributor, and the reactors at each stage are directly connected by short pipes; the online SO3 concentration detection device is a non-dispersive infrared analyzer or an ultraviolet absorption analyzer, which is equipped with a high-temperature sampling system, and the sampling pipeline is equipped with an electric heating or steam heating device; the controller adopts a feedforward-feedback composite control algorithm.

10. The apparatus according to claim 8, characterized in that: The integrated degassing-neutralization unit has a vertical co-shell structure, with the degassing chamber located at the top and the neutralization reactor at the bottom, separated by a porous baffle or deflector. The baffle has an opening rate of 40%-55% and a pore size of 5-15 mm, creating a partially shared gas phase space. The short connecting pipe is a vertically or inclined circular pipe with an inner diameter of 80-150 mm and a length of 0.5-1.2 meters. The mixer is a tubular static mixer or a Venturi jet mixer. The neutralization reactor is equipped with a jacketed heating device and an online pH monitoring device. In the tail gas condensation and absorption system, the condensing medium is chilled brine or ethylene glycol aqueous solution, and the condensation temperature is controlled between -5 and 5°C. The alkali absorption tower is a packed tower or spray tower structure, with a packing layer height of 3-8 meters or a spray density of 20-50. The absorption liquid circulation tank is equipped with an online monitoring device for liquid level and concentration, with a capacity of m³ / (m²·h). The waste alkaline liquid after absorption contains sodium sulfate, which is concentrated and crystallized and then reused in the neutralization process of sodium fatty alcohol polyoxyethylene ether sulfate or sodium alkylbenzene sulfonate.

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