Sodium alpha-olefin sulfonate production process capable of improving low-temperature stability

Abstract

The invention discloses a sodium alpha-olefin sulfonate production process capable of improving low-temperature stability, and relates to the field of chemical engineering, the production process comprises the following steps: step 1, sulfonating mixed olefin by using SO3 diluted by dry air, the molar ratio of SO3 to the mixed olefin being 1: (1.05-1.08); 2, after the sulfonation reaction is completed, the output acid ester material enters a neutralization system and then is subjected to aging, neutralization and three-stage hydrolysis to obtain the product alpha-olefin sodium sulfonate; the aging temperature is higher than the sulfonation temperature, the aging temperature is higher than the acid ester temperature, and the three-stage hydrolysis comprises first-stage hydrolysis, second-stage hydrolysis and third-stage hydrolysis; the temperature and pressure of the second-stage hydrolysis are higher than those of the first-stage hydrolysis and the second-stage hydrolysis. According to the invention, optimization of the aging temperature and three-stage hydrolysis process conditions has a synergistic effect on improvement of the low-temperature stability of the alpha-olefin sulfonate, the product quality is improved, the process efficiency is optimized, and the cost is reduced.

Description

Technical Field

[0001] The invention relates to the field of chemical industry, in particular to a production process of sodium alpha-olefin sulfonate. Background Art

[0002] Sodium α-olefin sulfonate (AOS for short) is an important anionic surfactant, mainly composed of olefin sulfonate, hydroxyalkyl sulfonate and disulfonate. Due to its excellent wetting, emulsification, solubilization, demulsification, dispersion, washing and other physical and chemical effects and corresponding practical use value, it is widely used in the textile industry, cosmetics, food, petroleum industry and other fields.

[0003] Sodium α-olefin sulfonate has good water solubility, foaming and wettability; excellent hard water resistance and good detergency; stable and compatible in acid and alkali media; low toxicity, low irritation and good biodegradability. Due to the excellent properties of sodium α-olefin sulfonate, it has a wide range of uses in both home and industry. In personal care products, it can be used in the formulation of hand soap, shampoo, toothpaste, bath gel, foam bath, etc.; in household washing, it is suitable for dishwashing detergent, heavy-duty laundry detergent, synthetic soap, liquid soap, wool, down cleaning agent; in industry, it can be used as emulsion polymerization emulsifier, petroleum recovery, concrete density improver, raw cotton (or wool) washing, textile and papermaking wetting agent, pesticide emulsifier, foam wall, fire-fighting foam agent, etc.

[0004] At present, sodium α-olefin sulfonate is a surface-active anionic mixture obtained by sulfonating, neutralizing and hydrolyzing α-olefin with sulfur trioxide, and its components are a mixture of 55-65% olefin sulfonate, 25-35% hydroxyalkyl sulfonate and 5-15% disulfonate. The market products are mainly in the form of liquid with the total mass fraction of these components being about 35%, or powdered form with about 90%. In the existing sulfonation production process of sodium α-olefin sulfonate, α-olefin is sulfonated with sulfur trioxide in a gas phase membrane sulfonation reactor. After cooling, the 35% sodium α-olefin sulfonate produced by the existing aging, neutralization and hydrolysis process will have some white substances at the bottom after being placed at low temperature. This substance is difficult to dissolve at room temperature and slowly turns into a coagulant, which brings inconvenience to downstream customers and a poor user experience. Analysis shows that this part of white substance is due to the by-product of sodium α-olefin sulfonate - sulfonic acid polymer, which slowly precipitates and agglomerates at low temperature. The polymer needs to be stirred and mixed at 40°C to dissolve evenly. Therefore, it is necessary to solve the low-temperature stability of sodium α-olefin sulfonate.

[0005] In the prior art, α-olefin pre-dissolved with a sulfonation catalyst is sulfonated in a gas phase membrane sulfonation reactor, and after cooling, α-olefin sulfonate is produced according to the existing aging, neutralization and hydrolysis process. This improvement solves the problem of insufficient reaction conversion rate by adding a catalyst during the sulfonation process, but the use of an external catalyst increases the production cost.

[0006] There is also a prior art that sulfonates a mixture of long-chain olefins and alkanes with a mixed gas of sulfur trioxide and air in a membrane sulfonator, and then separates and treats the mixture of olefin sulfonic acid, alkane mixture and sultone in the product by using an ultra-gravity reactor and molecular distillation, and neutralizes and hydrolyzes them to obtain olefin sulfonates and hydroxyalkyl sulfonates, and proposes a treatment method for the sulfonated tail gas. This improvement realizes the sulfonation reaction of the long-chain olefin and alkane mixture with gas phase sulfur trioxide in a membrane reactor, and a large amount of sulfonated tail gas is generated during the preparation process. Although a subsequent treatment method is proposed, a large amount of waste acid is added.

[0007] The market needs a sodium α-olefin sulfonate production process that can improve the poor low-temperature stability of α-olefin sulfonates while reducing costs and improving process efficiency. The present invention solves such a problem. Summary of the invention

[0008] In order to solve the shortcomings of the prior art, the purpose of the present invention is to provide a production process of sodium α-olefin sulfonate with improved low-temperature stability. By optimizing the aging temperature and the three-stage hydrolysis process conditions, the problem of poor low-temperature stability of α-olefin sulfonate is effectively improved, the product quality is improved, and the process efficiency and cost are optimized.

[0009] In order to achieve the above object, the present invention adopts the following technical solution:

[0010] A production process of sodium α-olefin sulfonate with improved low temperature stability comprises the following steps:

[0011] Step 1, sulfonating the mixed olefins using SO3 diluted with dry air, wherein the molar ratio of SO3 to the mixed olefins is 1:1.05-1.08;

[0012] Step 2: After the sulfonation reaction is completed, the acid ester material output enters the neutralization system and undergoes aging, neutralization, and three-stage hydrolysis to obtain the product sodium α-olefin sulfonate;

[0013] The aging temperature is greater than the sulfonation temperature, and the aging temperature is greater than the acid ester temperature. The three-stage hydrolysis includes: one-stage hydrolysis, two-stage hydrolysis, and three-stage hydrolysis; the temperature and pressure of the two-stage hydrolysis are greater than the temperature and pressure of the one-stage hydrolysis and the two-stage hydrolysis.

[0014] The above-mentioned production process of sodium α-olefin sulfonate with improved low-temperature stability includes step 1, molten sulfur is sent to a sulfur-burning furnace, countercurrently contacted with dry air blown from the bottom of the furnace, and burned to generate SO2, and the SO2 gas is catalytically oxidized through a conversion tower and a catalyst bed to generate SO2, and the SO3 gas is cooled and sent to a membrane sulfonator; the mixed olefin flows along the inner wall of the tube and reacts with the SO3 gas under high turbulence conditions to generate acid esters in an exothermic reaction; the molar ratio of SO3 to olefin is 1:1.05-1.08.

[0015] In the aforementioned process for producing sodium α-olefin sulfonate with improved low temperature stability, the mixed olefin is a C14-C16 mixed olefin, and the mixed olefin temperature is 30±5°C.

[0016] In the aforementioned process for producing sodium α-olefin sulfonate with improved low temperature stability, the mixed olefin is a mixture of C14 monoolefin and C16 monoolefin.

[0017] The aforementioned sodium α-olefin sulfonate production process with improved low-temperature stability has an aging temperature of 60-65° C. and an average aging residence time of 15-20 minutes.

[0018] The above-mentioned sodium α-olefin sulfonate production process with improved low-temperature stability has a hydrolysis temperature of 155-160° C., a hydrolysis pressure of 0.6-0.7 MPa, and an average residence time of 5-10 min in the first-stage hydrolysis; a second-stage hydrolysis temperature of 150-155° C., a second-stage hydrolysis pressure of 0.55-0.6 MPa, and an average residence time of 5-10 min in the second-stage hydrolysis; and a third-stage hydrolysis temperature of 155-160° C., a third-stage hydrolysis pressure of 0.55-0.65 MPa, and an average residence time of 5-10 min in the third-stage hydrolysis.

[0019] The aforementioned sodium α-olefin sulfonate production process with improved low temperature stability, wherein the acid ester material output after the sulfonation reaction in step 2 enters the neutralization system and is subjected to aging, neutralization, and three-stage hydrolysis to obtain the product sodium α-olefin sulfonate acid ester, comprises the following specific steps:

[0020] After the sulfonation reaction is completed, the acid ester material output enters the neutralization system for aging at an aging temperature of 60-65°C, and the average residence time of aging is 10-20min. The neutralization mixing pump and the neutralization circulation pump are started, and the liquid alkali feed regulating valve is opened to control the flow rate. At the same time, the process water is cut into the neutralization system through the flow meter, and the flow rates of the process water and liquid alkali are adjusted to maintain the circulation of the neutralization system. The hydrolysis booster pump is started through the neutralization circulation pump and the hydrolysis booster pump and the loop system. After the pressure of the neutralization circulation system is stabilized by adjusting the frequency, the hydrolysis system is fed; the neutralization system is neutralized by the liquid alkali regulating valve to maintain the neutralization alkalinity of 1.5-2.5%; the neutralized material is transported to the hydrolysis system through the booster pump, and the appropriate hydrolysis pressure is controlled by the post-hydrolysis pneumatic valve, and then the material temperature is increased through the heat exchanger. degree, the material temperature rises to the hydrolysis temperature; then enters the hydrolyzer for three-stage hydrolysis, the hydrolysis temperature of the first stage hydrolysis is 155-160°C, the hydrolysis pressure of the first stage is 0.6-0.7MPa, and the average residence time of the first stage hydrolysis is 5-10min; the hydrolysis temperature of the second stage is 150-155°C, the hydrolysis pressure of the second stage is 0.55-0.6MPa, and the average residence time of the second stage hydrolysis is 5-10min; the hydrolysis temperature of the third stage is 155-160°C, the hydrolysis pressure of the third stage is 0.55-0.65MPa, and the average residence time of the third stage hydrolysis is 5-10min; after the three-stage hydrolysis, the product is first subjected to heat exchange and cooling in a heat exchanger, and then cooled in a cooler, and then decolorized with hydrogen peroxide and adjusted to be qualified to obtain a qualified product.

[0021] In the aforementioned sodium α-olefin sulfonate production process with improved low-temperature stability, the flow rate of process water is 990 kg / h and the flow rate of liquid caustic soda is 355 kg / h.

[0022] In the aforementioned sodium α-olefin sulfonate production process with improved low temperature stability, the neutralization pressure of the neutralization system is 0.2-0.4 MPa, the neutralization temperature is 45±5° C., and the neutralization alkalinity is 1.5-2.5%.

[0023] The present invention is beneficial in that:

[0024] 1. The present invention reduces the formation of sulfonic acid polymers as byproducts by adjusting the aging temperature and combining the three-stage hydrolysis process, thereby achieving a synergistic effect in improving the poor low-temperature stability of α-olefin sulfonates;

[0025] 2. The method of the present invention has a simple process and can be realized by simply modifying the original sulfonation equipment, and the modification cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0027] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] Example 1

[0029] like Figure 1 As shown, a method for improving the low-temperature stability of sodium α-olefin sulfonate is provided, specifically: molten sulfur is sent to a sulfur-burning furnace at a rate of 87 kg / h, countercurrently contacts with process wind blown from the bottom of the furnace, and is burned to generate SO2, and the SO2 gas is catalytically oxidized through a conversion tower and a catalyst bed to generate SO3, and the SO3 gas is cooled at a concentration of 4-7% by volume fraction and sent to a membrane sulfonator; C14 and C16 monoolefins are respectively flowed into a high-speed mixer at a proper weight ratio of 65:35 for mixing, and the obtained mixed olefins are then introduced into a falling film sulfonation reactor with gaseous SO3 for sulfonation reaction. The mixed olefin organic material flows along the inner wall of the tube and reacts with SO3 gas under high turbulence conditions to generate acid esters through exothermic reaction. After the acid esters are aged for 10-15 minutes at a reaction temperature of 62±2℃, the neutralization mixing pump and the neutralization circulation pump are started, and the liquid alkali feed regulating valve is opened to control the flow rate. At the same time, the process water is cut into the neutralization system through the flow meter at 990kg / h, and the flow rate of liquid alkali is adjusted to flow in at 355kg / h to maintain the circulation of the neutralization system. The hydrolysis booster pump is started through the neutralization circulation pump, the hydrolysis booster pump and the loop system to control the neutralization circulation After the system pressure stabilizes at 0.2-0.4Mpa, the neutralization alkalinity is maintained at 1.5-2.5% through the liquid alkali regulating valve neutralization system; the neutralized material is transported to the hydrolysis system through a booster pump, and the appropriate hydrolysis pressure is controlled by the pneumatic valve after hydrolysis, and then the material temperature is raised through the heat exchanger to the hydrolysis temperature; then it enters the hydrolyzer for three-stage hydrolysis, and the product after the hydrolysis residence time of 10-15min is first cooled by heat exchange in the heat exchanger, and then cooled by the cooler, and then decolorized with hydrogen peroxide to obtain qualified products. The difference between the new process and the conventional process is that the new process uses three-stage hydrolysis to control the hydrolysis temperature and adjust the appropriate hydrolysis pressure, and the conventional process continuously maintains constant temperature and pressure. The process and indicators are shown in Table 1-1 and Table 1-2.

[0030] Table 1-1. Raw material parameters

[0031] Raw material name Traffic parameter values Sulfur: kg / h 87 C14 monoolefin: kg / h 344 C16 monoolefin: kg / h 185 Process water: kg / h 990 Liquid caustic soda: kg / h 355 Hydrogen peroxide:kg / h 15

[0032] Table 1-2. Differences in process and indicators

[0033]

[0034]

[0035] Note: The new process adopts a staged hydrolysis process, and no white substance is precipitated from the product at low temperature, and the improvement effect is better.

[0036] Example 2

[0037] SO3 diluted with dry air will flow into the sulfonation system at 630-650kg / h, and C14-16 mixed olefins will be evenly distributed in the tubes of the sulfonator through the distributor at 1520-1550kg / h, and will be sulfonated with the SO3 mixed gas entering the sulfonator; after the sulfonation reaction is completed, the acid ester material output enters the neutralization system for aging, neutralization, and three-stage hydrolysis to obtain the product α-olefin sodium sulfonate; as shown in Table 2, the new process adopts a combination of aging and three-stage hydrolysis to control temperature and pressure, and the conventional process continuously maintains constant temperature and pressure. The process and indicators are shown in Table 2-1 and Table 2-2.

[0038] The difference between the new process and the conventional process is: See Tables 2-1 and 2-2 for comparative processes and indicators.

[0039] Table 2-1. Raw material parameters

[0040] Raw material name Traffic parameter values Sulfur trioxide: kg / h 630-650 C14-16 mixed olefins: kg / h 1520-1550 Process water: kg / h 3200-3500 Liquid caustic soda: kg / h 765-790 Hydrogen peroxide:kg / h 32

[0041] Table 2-2 Control point parameters

[0042]

[0043]

[0044] Note: The new process combines aging and three-stage hydrolysis. No gel appears at the bottom of the product, and the product appearance is uniform and transparent.

[0045] Example 3

[0046] Liquid sulfur enters the sulfur burning furnace at 280-300kg / h and is ignited by the preheated hot air to generate SO2 gas. The SO2 gas is converted into SO3 mixed gas through the conversion tower, and then cooled to 40-50℃ before entering the sulfonation system. C14-16 mixed olefins are evenly distributed in the tubes of the sulfonator through the distributor at 1520-1550kg / h, and sulfonated with the SO3 mixed gas entering the sulfonator at a controlled temperature of 48-53℃; the aging temperature is controlled at 40-42℃ for 1 aging. After 8-20 minutes, the output acid ester material enters the neutralization system. After aging for 10-15 minutes at a reaction temperature of 62±2℃, the neutralization system is started, the neutralization temperature is controlled at 47-48℃, the hydrolysis booster pump is started to control the neutralization pressure at 0.2-0.3Mpa, and the product sodium α-olefin sulfonate is obtained by decolorization and adjustment. As shown in Table 3, the process adopts a two-stage hydrolysis combined with temperature control, and the conventional process continuously maintains constant temperature and pressure. The process and indicators are shown in Table 3-1 and Table 3-2.

[0047] Raw material name Traffic parameter values Sulfur: kg / h 280-300 C14-16 mixed olefins: kg / h 1700-1750 Process water: kg / h 3300-3600 Liquid caustic soda: kg / h 795-815 Hydrogen peroxide:kg / h 38

[0048]

[0049]

[0050] From the above experiments, it can be seen that the adjustment of the aging temperature and the three-stage hydrolysis process of the present invention achieve a synergistic effect in improving the poor low-temperature stability of α-olefin sulfonates.

[0051] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the above embodiments do not limit the present invention in any form, and any technical solution obtained by equivalent replacement or equivalent transformation falls within the protection scope of the present invention.

Claims

1. A process for producing sodium α-olefin sulfonate with improved low temperature stability, characterized in that: The steps include: Step 1, sulfonating the mixed olefins using SO3 diluted with dry air, wherein the molar ratio of SO3 to the mixed olefins is 1:1.05-1.08; Step 2: After the sulfonation reaction is completed, the acid ester material output enters the neutralization system and undergoes aging, neutralization, and three-stage hydrolysis to obtain the product sodium α-olefin sulfonate; The aging temperature is greater than the sulfonation temperature, the aging temperature is greater than the acid ester temperature, the three-stage hydrolysis includes: one-stage hydrolysis, two-stage hydrolysis, and three-stage hydrolysis; the temperature and pressure of the two-stage hydrolysis are greater than the temperature and pressure of the one-stage hydrolysis and the two-stage hydrolysis.

2. A process for producing sodium α-olefin sulfonate with improved low temperature stability according to claim 1, characterized in that: Step 1: The molten sulfur is sent to a sulfur burning furnace, countercurrently contacted with dry air blown from the bottom of the furnace, and burned to generate SO2. The SO2 gas is catalytically oxidized through a conversion tower and a catalyst bed to generate SO2. The SO3 gas is cooled and sent to a membrane sulfonator; the mixed olefins flow along the inner wall of the tube and react with the SO3 gas under high turbulence conditions to generate acid esters in an exothermic reaction; the molar ratio of SO3 to olefins is 1:1.05-1.

08.

3. A process for producing sodium α-olefin sulfonate with improved low temperature stability according to claim 1 or 2, characterized in that: The mixed olefins are C14-C18 mixed olefins, and the mixed olefin temperature is 20±5°C.

4. A process for producing sodium α-olefin sulfonate with improved low temperature stability according to claim 1 or 2, characterized in that: The mixed olefin is a mixture of C14 monoolefin and C16 monoolefin.

5. The process for producing sodium α-olefin sulfonate with improved low temperature stability according to claim 1, characterized in that: The aging temperature is 60-65° C., and the average aging residence time is 15-20 minutes.

6. The process for producing sodium α-olefin sulfonate with improved low temperature stability according to claim 1, characterized in that: The hydrolysis temperature of the first-stage hydrolysis is 155-160°C, the hydrolysis pressure of the first-stage hydrolysis is 0.6-0.7MPa, and the average residence time of the first-stage hydrolysis is 5-10min; the hydrolysis temperature of the second-stage hydrolysis is 150-155°C, the hydrolysis pressure of the second-stage hydrolysis is 0.55-0.6MPa, and the average residence time of the second-stage hydrolysis is 5-10min; the hydrolysis temperature of the third-stage hydrolysis is 155-160°C, the hydrolysis pressure of the third-stage hydrolysis is 0.55-0.65MPa, and the average residence time of the third-stage hydrolysis is 5-10min.

7. The process for producing sodium α-olefin sulfonate with improved low temperature stability according to claim 1, characterized in that: The specific steps of the acid ester material output after the sulfonation reaction in step 2 enters the neutralization system and undergoes aging, neutralization, and three-stage hydrolysis to obtain the product α-olefin sodium sulfonate include: After the sulfonation reaction is completed, the acid ester material output enters the neutralization system for aging at an aging temperature of 60-65°C, and the average residence time of aging is 15-20min. The neutralization mixing pump and the neutralization circulation pump are started, and the liquid alkali feed regulating valve is opened to control the flow rate. At the same time, the process water is cut into the neutralization system through the flow meter, and the flow rates of the process water and liquid alkali are adjusted to maintain the circulation of the neutralization system. The hydrolysis booster pump is started through the neutralization circulation pump and the hydrolysis booster pump and the loop system. After the pressure of the neutralization circulation system is stabilized by adjusting the frequency, the hydrolysis system is fed; the neutralization system is neutralized by the liquid alkali regulating valve to maintain the neutralization alkalinity at 2.1-2.3%; the neutralized material is transported to the hydrolysis system through the booster pump, and the appropriate hydrolysis pressure is controlled by the post-hydrolysis pneumatic valve, and then the material temperature is increased through the heat exchanger. degree, the material temperature rises to the hydrolysis temperature; then enters the hydrolyzer for three-stage hydrolysis, the hydrolysis temperature of the first stage hydrolysis is 155-160°C, the hydrolysis pressure of the first stage is 0.6-0.7MPa, and the average residence time of the first stage hydrolysis is 5-10min; the hydrolysis temperature of the second stage is 150-155°C, the hydrolysis pressure of the second stage is 0.55-0.6MPa, and the average residence time of the second stage hydrolysis is 5-10min; the hydrolysis temperature of the third stage is 155-160°C, the hydrolysis pressure of the third stage is 0.55-0.65MPa, and the average residence time of the third stage hydrolysis is 5-10min; after the three-stage hydrolysis, the product is first subjected to heat exchange and cooling in a heat exchanger, and then cooled in a cooler, and then decolorized with hydrogen peroxide and adjusted to be qualified to obtain a qualified product.

8. A process for producing sodium α-olefin sulfonate with improved low temperature stability according to claim 7, characterized in that: The flow rate of the process water is 990 kg / h, and the flow rate of the liquid caustic soda is 355 kg / h.

9. The process for producing sodium α-olefin sulfonate with improved low temperature stability according to claim 7, characterized in that: The neutralization pressure of the neutralization system is 0.2-0.3Mpa, the neutralization temperature is 45±5°C, and the neutralization alkalinity is 1.5-2.5%.

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