Preparation method of Vocs integrated rotational flow emulsion

Abstract

The invention discloses a preparation method of Vocs integrated rotational flow emulsion, which comprises the following steps: S1, mixing deionized water with a chelating agent to prepare a continuous phase solution for removing metal ions; s2, compounding an anionic surfactant and a nonionic surfactant, dissolving in a mixed solvent of ethanol and acetone, and adding a functional additive to form a surfactant solution; s3, pre-dispersing the surfactant solution and the continuous phase solution to obtain a primary oil-in-water dispersion; the preparation method has the beneficial effects that the mass transfer efficiency is improved: the specific surface area of the nanoscale liquid drops (100-200nm) is improved by more than 3 times compared with that of the traditional emulsion, and the mass transfer coefficient is improved by 50-70% and the absorption equilibrium time is shortened by 60% in combination with low interfacial tension; metal ions are removed through chelating treatment, a pH buffer system is matched, the emulsion can be stably stored for 6 months under the conditions that the pH is 5-9 and the temperature is smaller than or equal to 60 DEG C, and the centrifugal layering rate (3000r / min, 30min) is smaller than 5%.

Description

Technical Field

[0001] The present invention relates to the technical field of emulsions, and specifically to a method for preparing a Vocs integrated cyclone liquid emulsion. Background Art

[0002] VOCs, namely volatile organic compounds, are an organic pollutant commonly present in the atmosphere, mainly originating from industries such as paint chemicals, steel mills, and rubber processing. Volatile organic compounds VOCs are mainly hydrocarbons and can be divided into aromatic hydrocarbons (benzene, toluene, xylene, styrene, etc.); aliphatic hydrocarbons (gasoline, solvent oil, cyclohexane, hexane, octane, etc.); aldehydes, alcohol ethers, esters, ketones, alkenes, etc.

[0003] With the rapid development of industries such as industrial painting, printing, and chemical engineering, the air pollution problem caused by Vocs emissions is becoming increasingly severe. Currently, there are two major technical bottlenecks in the mainstream absorption method for treating Vocs: one is the low mass transfer efficiency at the phase interface between the traditional absorbent and Vocs, resulting in insufficient absorption capacity; the other is the poor stability of the emulsion system, which is prone to stratification and demulsification, affecting the recycling performance. In the existing technology, the method of improving by adding surfactants has problems such as unclear emulsion process parameters and complex regeneration treatment, and it is difficult to meet the requirements of large-scale industrial applications.

[0004] However, the traditional absorbent has the following technical defects: insufficient mass transfer efficiency: the gas-liquid interface mass transfer resistance between the conventional absorbent and Vocs is large, the droplet size distribution is uneven (usually >500nm), and the specific surface area is small, resulting in a slow absorption rate and a low saturated absorption capacity; poor emulsion stability: the emulsion system formed by a single surfactant is easily affected by factors such as pH value, temperature, and metal ions, resulting in demulsification and stratification, affecting the recycling of the absorbent; high regeneration cost: the adsorption capacity of the traditional absorbent for Vocs is limited, and high-temperature distillation or chemical treatment is required during regeneration, with high energy consumption and easy to cause secondary pollution.

[0005] After retrieval, the patent with the publication number CN108905632A proposed a Vocs absorbent and its preparation method, but it uses an ordinary stirring emulsification process with insufficient control accuracy of droplet size and does not solve the dispersion stability problem of the nano adsorbent in the emulsion. Therefore, there is an urgent need to develop a preparation method that optimizes the performance of the emulsion through precise process control. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for preparing a Vocs integrated cyclone liquid emulsion, which realizes high mass transfer efficiency, structural stability, and convenient regeneration performance of the absorbent through a method for preparing a Vocs integrated cyclone liquid emulsion with three-stage gradient cyclone emulsification, surfactant compounding, and modification with nano-functional materials, so as to solve the problems raised in the above background art.

[0007] To achieve the above object, the present invention provides the following technical solution: a method for preparing an integrated cyclone liquid emulsion of Vocs, comprising the following steps:

[0008] S1. Mix deionized water with a chelating agent to prepare a continuous phase solution for removing metal ions;

[0009] S2. Compound an anionic surfactant and a non-ionic surfactant, dissolve them in a mixed solvent of ethanol and acetone, and add a functional additive to form a surfactant solution;

[0010] S3. Pre-disperse the surfactant solution and the continuous phase solution to obtain a preliminary water-in-oil dispersion;

[0011] S4. Perform a three-stage gradient cyclone emulsification treatment on the dispersion system, control the emulsification speed to increase by 300 - 500 r / min for each stage, and the temperature to increase by 5 - 10 °C step by step, and finally form a nano-scale emulsion;

[0012] S5. Add a surface-modified nano adsorbent to the emulsion, and obtain the target emulsion through ultrasonic dispersion.

[0013] Preferably, the anionic surfactant is sodium dodecylbenzenesulfonate, the non-ionic surfactants include sodium lauryl polyoxyethylene ether sulfate and Tween-80, and the mass ratio of the three is (6 - 12):(4 - 8):(2 - 5).

[0014] Preferably, the volume ratio of ethanol to acetone is 2:1 - 3:1, and the critical micelle concentration (CMC) of the surfactant compounding system is reduced by 30% - 50% compared with that of a single surfactant.

[0015] Preferably, the average particle size of the final droplets in the three-stage cyclone emulsification is 100 - 200 nm, and the particle size distribution index (PDI) < 0.3.

[0016] Preferably, the nano adsorbent is silane-modified SiO2 or activated carbon microparticles, with a particle size of 50 - 100 nm, and the addition amount accounts for 1% - 3% of the total mass of the emulsion.

[0017] Preferably, the functional additives include a pH buffer, an antifoaming agent, and a preservative, and the pH buffer stabilizes the pH of the emulsion at 6.5 - 7.5.

[0018] Preferably, the surface-modified nano adsorbent is modified SiO2 or activated carbon microparticles, and its particle size is 50 - 100 nm.

[0019] Preferably, the chelating agent is disodium ethylenediaminetetraacetate.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] Mass transfer efficiency improvement: The specific surface area of nanoscale droplets (100 - 200 nm) is more than 3 times that of traditional emulsions. Combining with low interfacial tension, the mass transfer coefficient is increased by 50% - 70%, and the absorption equilibrium time is shortened by 60%.

[0022] Excellent stability: Chelation treatment removes metal ions, combined with a pH buffer system, enabling the emulsion to be stably stored for 6 months at pH 5 - 9 and temperature ≤ 60°C, and the centrifugal stratification rate (3000 r / min, 30 min) < 5%.

[0023] Outstanding regeneration performance: The introduction of a nano - adsorbent increases the saturated absorption capacity by 40% - 60%. During regeneration, high - efficiency desorption of VOCs can be achieved through low - temperature vacuum distillation (40 - 50°C, vacuum degree - 0.08 MPa), and the regeneration energy consumption is reduced by more than 40%. Detailed implementation mode

[0024] The present invention provides a technical solution: A method for preparing an integrated cyclone liquid emulsion for VOCs, comprising the following steps:

[0025] S1: Prepare raw materials by mass fraction:

[0026] Continuous - phase solution: Add 0.1 - 0.5 parts of disodium ethylenediaminetetraacetate to 50 - 80 parts of deionized water, stir at 40 - 60°C for 10 - 15 min to remove metal ions, and adjust the pH to 6.5 - 7.5.

[0027] Surfactant compound system: Mix 6 - 12 parts of sodium dodecylbenzenesulfonate, 4 - 8 parts of sodium lauryl polyoxyethylene ether sulfate, and 2 - 5 parts of Tween - 80, add 10 - 20 parts of ethanol and 5 - 10 parts of acetone, and stir at 30 - 40°C until completely dissolved.

[0028] Functional additives: 2 - 4 parts of polydimethylsiloxane emulsion (defoamer), 1 - 3 parts of sodium benzoate (preservative), 1 - 2 parts of Tris - HCl buffer (pH buffer).

[0029] S2: Preliminary dispersion and mixing

[0030] Add the surfactant compound solution to the reaction kettle, stir at a speed of 200 - 300 r / min, and at the same time add the continuous - phase solution at a flow rate of 5 - 10 L / min at a constant speed to form a preliminary oil - in - water (O / W) dispersion system, stir for 30 - 40 min, and control the system temperature at 30 - 40°C.

[0031] S3: Three - stage gradient cyclone emulsification

[0032] Transfer the pre - dispersed liquid to a high - shear cyclone emulsifier for three - stage emulsification treatment:

[0033] Primary emulsification: Rotation speed 1500 - 1800 r / min, shearing for 10 - 15 min to form a coarse emulsion with an average particle size of 5 - 10 μm;

[0034] Secondary emulsification: The rotation speed is increased to 2000 - 2200 r / min, shearing for 20 - 25 min, and the particle size is refined to 2 - 5 μm, with a temperature increase of 5 - 10 °C during the process;

[0035] Tertiary emulsification: Rotation speed 2500 - 3000 r / min, shearing for 5 - 10 min, finally forming a nano - emulsion with a uniform particle size distribution, PDI < 0.3, and an average particle size of 100 - 200 nm, controlling the final temperature ≤ 50 °C.

[0036] S4: Nano - functional modification

[0037] Add 1 - 3% of surface - modified nano - adsorbent based on the total amount to the emulsion, and perform ultrasonic dispersion for 15 - 20 min under the conditions of 40 - 60 kHz and 200 - 300 W, so that the adsorbent is uniformly dispersed in the continuous phase to form an "emulsification absorption - nano - adsorption" synergistic system, obtaining the target emulsion.

[0038] Example 1

[0039] General - type emulsion

[0040] Raw material ratio: 60 parts of deionized water (containing 0.3 part of disodium ethylenediaminetetraacetate), 8 parts of sodium dodecylbenzenesulfonate, 6 parts of sodium lauryl polyoxyethylene ether sulfate, 3 parts of Tween - 80, 15 parts of ethanol, 8 parts of acetone, 3 parts of defoamer, 2 parts of preservative, 1.5 parts of buffer, and 2 parts of modified SiO2 nanoparticles;

[0041] Pre - dispersion: Stir at 250 r / min for 40 min at 30 °C;

[0042] Cyclone emulsification: Primary 1800 r / min × 15 min, secondary 2200 r / min × 20 min (heating to 40 °C), tertiary 2500 r / min × 10 min (heating to 45 °C);

[0043] Ultrasonic dispersion: Ultrasonic treatment at 50 kHz and 250 W for 20 min.

[0044] Performance parameters: Average droplet particle size 180 nm, surface tension 22 mN / m, toluene absorption capacity 125 g / L, regeneration desorption rate 92%

[0045] Example 2

[0046] Emulsifier for high - concentration waste gas treatment

[0047] Raw material adjustment: 50 parts of deionized water, 12 parts of sodium dodecylbenzenesulfonate, 8 parts of sodium lauryl polyoxyethylene ether sulfate, 5 parts of Tween-80, 20 parts of ethanol, 10 parts of acetone, and 3 parts of activated carbon nanoparticles;

[0048] Emulsification process: The rotation speeds of three-stage emulsification are 1500 r / min, 2000 r / min, and 3000 r / min respectively, the treatment time for each stage is 15 min, 25 min, and 10 min, and the final temperature is 50 °C;

[0049] Performance parameters: The absorption efficiency of p-xylene is over 95%, and the performance attenuation is <8% after 50 cycles of reuse.

[0050] Parameter comparison

[0051]

[0052] In the present invention, although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing an integrated cyclone liquid emulsion for VOCs, characterized in that, It includes the following steps: S1. Mix deionized water with a chelating agent to prepare a continuous phase solution for removing metal ions; S2. Compound an anionic surfactant and a nonionic surfactant, dissolve them in a mixed solvent of ethanol and acetone, and add a functional additive to form a surfactant solution; S3. Pre-disperse the surfactant solution and the continuous phase solution to obtain a preliminary water-in-oil dispersion; S4. Perform three-stage gradient swirl emulsification treatment on the dispersion system, control the emulsification speed to increase by 300 - 500 r / min for each stage, and the temperature to increase by 5 - 10 °C for each stage, and finally form a nano-scale emulsion; S5. Add a surface-modified nano adsorbent to the emulsion and obtain the target emulsion through ultrasonic dispersion.

2. The manufacturing method of an integrated cyclone liquid emulsion for VOCs according to claim 1, characterized in that: The anionic surfactant is sodium dodecylbenzenesulfonate, and the nonionic surfactants include sodium lauryl polyoxyethylene ether sulfate and Tween - 80, and the mass ratio of the three is (6 - 12):(4 - 8):(2 - 5).

3. The manufacturing method of an integrated cyclone liquid emulsion for VOCs according to claim 1, characterized in that: The volume ratio of ethanol to acetone is 2:1 - 3:1, and the critical micelle concentration of the surfactant compounding system is reduced by 30% - 50% compared with that of a single surfactant.

4. The manufacturing method of an integrated vortex liquid emulsion for VOCs according to claim 1, characterized in that: The average particle size of the final droplets in the three-stage swirl emulsification is 100 - 200 nm, and the particle size distribution index < 0.

3.

5. The manufacturing method of an integrated swirl liquid emulsion for VOCs according to claim 1, characterized in that: The nano adsorbent is silane-modified SiO2 or activated carbon particles, with a particle size of 50 - 100 nm, and the addition amount accounts for 1% - 3% of the total mass of the emulsion.

6. The manufacturing method of an integrated cyclone liquid emulsion for VOCs according to claim 1, characterized in that: The functional additive includes a pH buffer, an antifoaming agent, and a preservative, and the pH buffer stabilizes the pH of the emulsion at 6.5 - 7.

5.

7. The manufacturing method of an integrated cyclone liquid emulsion for VOCs according to claim 1, characterized in that: The chelating agent is disodium ethylenediaminetetraacetate.

8. The manufacturing method of an integrated vortex liquid emulsion for VOCs according to claim 1, characterized in that: The surface-modified nano adsorbent is modified SiO2 or activated carbon particles, and its particle size is 50 - 100 nm.

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