Long-chain alkylbenzene refined decolorization and impurity removal method

Abstract

The invention discloses a long-chain alkylbenzene refined decolorization and impurity removal method which comprises the following steps: (1) pumping long-chain alkylbenzene into a stirring tank, adopting low-pressure steam heat tracing, and starting a stirrer to control the stirring process; (2) adding a small amount of acid-activated carclazyte for multiple times while stirring; and (3) after stirring is completed, standing and carrying out third-stage filtration on the supernate. By controlling the stirring rotating speed, the temperature, the carclazyte addition amount and the standing time, the decoloration and impurity removal effects of the long-chain alkylbenzene are optimized. The method is simple and convenient to operate, low in equipment requirement and excellent in impurity removal performance, the prepared long-chain alkylbenzene product has low chromaticity, low bromine index and proper viscosity, and the product index is superior to that of a traditional method.

Description

Technical Field

[0001] The invention belongs to the field of chemical industry, and particularly relates to a method for finely decolorizing and removing impurities from long-chain alkylbenzene. Background Art

[0002] Long-chain alkylbenzenes are widely used in the fields of petroleum, chemical industry and light industry as raw materials for lubricants and surfactants. However, colored impurities are easily carried in the production process, which affects its purity and market value. Existing refining methods are complicated to operate, require high equipment, and take a long time to process, and the effect of decolorization and impurity removal is poor. Therefore, there is an urgent need for a decolorization and impurity removal method that is simple to operate, low in cost and effective to improve the quality of long-chain alkylbenzenes to meet market demand. Summary of the invention

[0003] In order to solve the above problems, the present invention discloses a method for refined decolorization and impurity removal of long-chain alkylbenzene, which can effectively reduce the bromine index and impurity content, shorten the standing and filtering time, and improve production efficiency while removing colored impurities.

[0004] To achieve the above object, the technical solution of the present invention is as follows: A method for fine decolorization and impurity removal of long-chain alkylbenzene comprises the following steps: S1. Pump the long-chain alkylbenzene into the stirring tank, start the agitator to stir under low-pressure steam heating conditions; S2. Add clay in small amounts several times during the mixing process; S3. After the stirring is completed, the mixture is allowed to stand, and the supernatant is filtered to obtain the decolorized and impurity-free long-chain alkylbenzene.

[0005] As an improvement of the present invention, the long-chain alkylbenzene in step S1 is C20~24 alkylbenzene.

[0006] As an improvement of the present invention, in step S1, after the liquid level of the long-chain alkylbenzene in the stirring tank reaches 50%, the agitator is started for stirring, the agitator speed is 1200-1300 r / min, the stirring time is 30-60 min, the stirring environment pressure is 0.2-0.25 MPa, and the steam temperature is 80-90°C.

[0007] As an improvement of the present invention, the standing time of step S3 is 60 to 120 minutes.

[0008] As an improvement of the present invention, the filtering in step S2 is a three-stage filtering.

[0009] As an improvement of the present invention, the step of preparing the white clay in step S2 is as follows: (1) Dry the bentonite (generally calcium-based bentonite) until the moisture content is less than 15%, remove the intercalated stones, and crush it to 147-74μm. Weathered bentonite does not need to be crushed. If the sand content is high, the sand particles need to be removed; (2) Mixing bentonite with water, adding acid to the mixed bentonite slurry for activation, and heating and stirring; (3) Add water and wash continuously. Since bentonite has fine particles and is not easy to settle, an appropriate amount of high-efficiency flocculant can be added to accelerate the settling. After the washing liquid becomes neutral, most of the water in the activated white clay slurry after washing is removed by filter pressing or vacuum suction filtration, and the product is dried until the water content is less than 8%. (4) Use a Raymond mill, vibration mill, etc. to grind the dried activated clay to 74 μm. If the dried product is a powder product, no further grinding is required.

[0010] As an improvement of the present invention, the acid in step (2) is any one of hydrochloric acid and sulfuric acid. For bentonite containing calcite, hydrochloric acid is preferably used for activation. The mass ratio of bentonite to acid is 1:0.3-0.6, and the water-to-soil ratio is 0.8-1:1.

[0011] As an improvement of the present invention, the activation temperature in step (2) is 50-100° C. and the reaction time is 2-8 hours.

[0012] As an improvement of the present invention, the quality of the long-chain alkylbenzene product obtained in step S3 reaches the following technical indicators: Bromine index ≤90mgBr / 100g oil Viscosity ≤19.2 (40℃) mm3 / s Average molecular weight ≤387 Chroma ≤ 0.5.

[0013] The refined decolorization and impurity removal method provided by the present invention can effectively reduce the bromine index and impurity content while removing colored impurities. The experimental results show that the color of the long-chain alkylbenzene product treated by the method of the present invention can be controlled at ≤0.5, the bromine index is reduced to ≤90 mgBr / 100g oil, the viscosity reaches ≤19.2 mm³ / s (40℃), and the average molecular weight is ≤387. Compared with the traditional decolorization and impurity removal method, this method has the following advantages: (1) Efficient decolorization: By adding activated clay in small amounts multiple times, the clay is fully in contact with the impurities in the long-chain alkylbenzene, thereby enhancing the adsorption effect of the impurities.

[0014] (2) Complete removal of impurities: The three-stage filtration system in this method further removes the fine impurity particles remaining during the stirring process, significantly improving the purity of the product. The key indicators of the product such as color and bromine index are reduced by 5% through the first stage filtration, by 10% through the second stage filtration, and by 20% through the third stage filtration.

[0015] (3) Improving product performance and stability: In the present application, the white clay is produced by a wet method. The white clay prepared by the present invention has high activity and adsorption capacity, and at the same time, is free of water-soluble impurities and has a simple process. DETAILED DESCRIPTION

[0016] The present invention will be further explained below in conjunction with specific implementation modes. It should be understood that the following specific implementation modes are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0017] Embodiment 1 Dry the bentonite until the water content is less than 15% and crush it to 147-74μm. Mix the bentonite with water at a water-to-soil ratio of 0.9:1, and add hydrochloric acid at a mass ratio of 1:0.5 for acid activation. The activation temperature is 75°C and the reaction time is 6 hours. Add water and wash repeatedly until the washing liquid is neutral, filter and dry until the water content is less than 8%. Grind the dried clay to less than 74μm to obtain activated clay.

[0018] Pump C20~24 long-chain alkylbenzene into the stirring tank and control the liquid level to reach 50% of the height of the stirring tank. Start the agitator, set the speed to 1250 r / min, the stirring environment temperature to 85℃, and the pressure to 0.23 MPa. The stirring time is controlled to 45 minutes. During the stirring process, add activated white clay in small amounts in five times, adding 20% ​​of the total amount each time. After stirring, let it stand for 90 minutes, take the supernatant and filter it through three stages.

[0019] Embodiment 2 On the basis of Example 1, the agitator speed was adjusted to 1300 r / min, the stirring temperature was adjusted to 90° C., the stirring pressure was adjusted to 0.25 MPa, the stirring time was extended to 60 minutes, and the other conditions remained unchanged.

[0020] Embodiment 3 On the basis of Example 1, the temperature of acid activation of white clay was increased to 85° C., the mass ratio of bentonite to acid was 1:0.6, the activation reaction time was shortened to 4 hours, and other steps remained the same.

[0021] Embodiment 4 On the basis of Example 1, the white clay was added in small amounts in seven times, with each addition accounting for about 14.3% of the total amount, and the other conditions remained unchanged.

[0022] Comparative Example 1 The long-chain alkylbenzene refined decolorization and impurity removal process of the prior art is adopted. The difference from Example 1 is that in the traditional process, the bentonite is crushed to less than 147 μm, and is directly added to the stirring tank without acid activation treatment. The white clay is added at one time, and the total amount is consistent with the white clay amount in Example 1. The stirring speed is set to 1000 r / min, the stirring temperature is 80°C, the pressure is 0.15 MPa, and the stirring time is 30 minutes. After standing for 60 minutes, a primary filtration is performed.

[0023] In different embodiments and comparative examples, the main quality index data of long-chain alkylbenzene obtained by testing are as follows: Experiment number Chroma Bromine index (mgBr / 100g oil) Viscosity (40℃, mm³ / s) Average molecular weight Embodiment 1 0.45 85 18.9 385 Embodiment 2 0.42 82 18.7 384 Embodiment 3 0.44 83 18.8 386 Embodiment 4 0.46 84 18.9 385 Comparative Example 1.2 110 20.5 395 It can be seen from the above table that the chromaticity of the long-chain alkylbenzene products of Examples 1 to 4 of the present invention all reached ≤0.5, the bromine index ≤90 mgBr / 100g oil, and the viscosity and molecular weight all met the high quality standards, which were significantly better than the products obtained by the traditional process in the comparative example. In terms of chromaticity, bromine index, viscosity and average molecular weight, each index of the embodiment is better than the comparative example, indicating that the present invention has significant advantages in decolorization and impurity removal effect, reduction of bromine index and improvement of product performance.

[0024] In addition, the bleaching clay preparation process of the present application adopts a wet process, and the bleaching clay preparation process also includes a dry process and a semi-wet process. The previous operation of the dry process is the same as the wet process, but the deacidification is volatilized by roasting, and there is no washing operation. Dry production saves water and avoids the discharge of acidic wastewater, but the water-soluble impurities in the product, such as salts such as Al, K, Na, Ca, Mg, and Fe, are not removed, affecting the product quality; The semi-wet method of producing activated clay is to use a 5% sulfuric acid aqueous solution to activate bentonite for 4 hours at 200-250°C and 1.5-2.0MPa (15-20 atmospheres) in an autoclave. Due to the low acid concentration used, the washing product consumes less water, but the high temperature and high pressure operation is difficult, which limits the promotion and application of this method.

[0025] It should be noted that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention, and these improvements and modifications all fall within the scope of protection of the claims of the present invention.

Claims

1. A method for fine decolorization and impurity removal of long-chain alkylbenzene, characterized in that: The following steps are involved: S1. Pumping long-chain alkylbenzene into a stirring tank, starting the agitator to stir under low-pressure steam heating conditions; S2. Add clay in small amounts several times during the mixing process; S3. After the stirring is completed, the mixture is allowed to stand, and the supernatant is filtered to obtain the decolorized and impurity-free long-chain alkylbenzene.

2. A method for refined decolorization and impurity removal of long-chain alkylbenzene according to claim 1, characterized in that: In the step S1, the long-chain alkylbenzene is C20-24 alkylbenzene.

3. A method for refined decolorization and impurity removal of long-chain alkylbenzene according to claim 2, characterized in that: In the step S1, after the liquid level of the long-chain alkylbenzene in the stirring tank reaches 50%, the agitator is started for stirring, the agitator speed is 1200-1300 r / min, the stirring time is 30-60 min, the stirring environment pressure is 0.2-0.25 MPa, and the steam temperature is 80-90° C.

4. A method for refined decolorization and impurity removal of long-chain alkylbenzene according to claim 2, characterized in that: The standing time of step S3 is 60 to 120 minutes.

5. A method for refined decolorization and impurity removal of long-chain alkylbenzene according to claim 2, characterized in that: The filtering in step S2 is three-stage filtering.

6. A method for refined decolorization and impurity removal of long-chain alkylbenzene according to claim 1, characterized in that: The steps of preparing the bleaching clay in step S2 are as follows: (1) Dry the bentonite until the moisture content is less than 15%, remove the intercalated stones, and crush it to 147-74 μm; (2) Mixing bentonite with water, adding acid to the mixed bentonite slurry for activation, and heating and stirring; (3) Add water and wash continuously until the washing liquid becomes neutral, then filter and dry until the moisture content of the product is less than 8%; (4) Grind the dried activated clay to 74 μm.

7. A method for refined decolorization and impurity removal of long-chain alkylbenzene according to claim 6, characterized in that: In the step (2), the acid is any one of hydrochloric acid, sulfuric acid and organic acid, the mass ratio of bentonite to acid is 1:0.3-0.6, and the water-to-soil ratio is 0.8-1:

1.

8. A method for refined decolorization and impurity removal of long-chain alkylbenzene according to claim 6, characterized in that: In step (2), the activation temperature is 50-100° C. and the reaction time is 2-8 hours.

9. A method for refined decolorization and impurity removal of long-chain alkylbenzene according to any one of claims 1 to 8, characterized in that: The quality of the long-chain alkylbenzene product obtained in step S3 meets the following technical indicators: Bromine index ≤90mgBr / 100g oil Viscosity ≤19.2 (40℃) mm3 / s Average molecular weight ≤387 Chroma ≤ 0.5.