Method for high-efficiency absorption of acetone by using imidazole ionic liquid

Abstract

The present application relates to a kind of method for high-efficiency absorption of acetone using imidazole ionic liquid.The method selects 1-butyl-3-methylimidazolium hexafluorophosphate as absorbent by COSMO-RS model, and efficiently absorbs acetone emitted into air by coating industry.Through the water content of ionic liquid, tower flow rate, acetone purged by nitrogen is preferentially dissolved in 1-butyl-3-methylimidazolium hexafluorophosphate.The absorbed ionic liquid can be recycled after simple regeneration treatment, and the absorption performance does not decrease significantly.Further, the viscosity of 1-butyl-3-methylimidazolium hexafluorophosphate can be reduced by adding appropriate amount of water to dilute it, thereby significantly improving the absorption rate and capacity of acetone.The absorption method provided by the method is simple to operate, the absorbent is renewable, and environmentally friendly, which can effectively solve the problem of waste gas treatment containing acetone in coating and other industries.

Description

Technical Field

[0001] This invention belongs to the field of gas absorption and chemical separation technology, specifically relating to a method for efficiently absorbing acetone using imidazole ionic liquids. Background Technology

[0002] Acetone is an organic solvent widely used in industries such as coatings, pharmaceuticals, and electronic cleaning. It is highly volatile and emits large quantities of acetone, which can irritate and damage the human central nervous system and respiratory system. It also easily participates in photochemical reactions to form secondary pollution, so effective treatment is urgently needed.

[0003] Currently, the main methods for treating acetone in industrial waste gas include adsorption, condensation, catalytic combustion, and absorption. Adsorption commonly uses activated carbon or molecular sieves as adsorbents, but after adsorption saturation, desorption with water vapor or replacement of the adsorbent is required. This method involves large equipment, complex post-treatment, and the potential for secondary pollution, and also incurs high operating costs. Condensation recovers acetone by lowering the temperature to achieve supersaturation, but it consumes a lot of energy and has limited effectiveness for low-concentration waste gas, often requiring combination with other technologies. Catalytic combustion oxidizes and decomposes acetone into carbon dioxide and water under the action of a catalyst. While it has high treatment efficiency, it requires high-temperature operation, resulting in high equipment investment and operating costs, and poor adaptability to intermittent emissions. All of the above methods generally suffer from high energy consumption, complex equipment, or difficulties in regeneration when treating acetone waste gas.

[0004] Absorption methods have attracted attention due to their continuous operation, simple equipment, and large processing capacity. Traditional absorbents are mainly water or organic solvents. CN111282433A reports a method for treating volatile organic compounds (VOCs) waste gas. Silicone oil absorbs VOCs in an absorption tower, becoming a rich absorbent. It then enters a desorption tower for heating and distillation to remove VOCs for recovery. The desorbed silicone oil enters a biological treatment unit to degrade residual VOCs, and is then returned to the absorption tower as a lean absorbent for recycling. However, the desorption heating process is energy-intensive, and the biological treatment unit is greatly affected by fluctuations in temperature, pH, and waste gas flow rate, resulting in unstable efficiency. CN107224988A reports a catalyst, its preparation method, and its application in VOCs absorption. The catalyst prepared by this method has good VOCs treatment effect and high degradation efficiency, but the preparation process is complex. Therefore, developing an ionic liquid absorbent with large absorption capacity, good selectivity, suitable viscosity, and easy regeneration for acetone is of significant practical importance for the efficient purification of acetone waste gas. Summary of the Invention

[0005] The purpose of this invention is to provide a method for efficiently absorbing acetone using imidazole ionic liquids. The method uses imidazole ionic liquids, which have high absorption efficiency, good hydrophobicity and good thermal stability, as absorbents to achieve efficient absorption of acetone. The ionic liquids can be recycled, thereby improving the problems of insufficient separation performance and environmental risks of existing methods for absorbing volatile organic compounds.

[0006] Technical solution

[0007] This invention addresses the difficulty in separating acetone emitted by the coatings industry by proposing a method for absorbing acetone from the N2 environment. This method is mild, environmentally friendly, and achieves an acetone absorption efficiency of up to 97%.

[0008] The present invention is achieved through the following technical solution.

[0009] A method for efficiently absorbing acetone using imidazole ionic liquids includes the following steps: (1) Drying the ionic liquid; the absorbent is mainly an imidazole ionic liquid; wherein the imidazole ionic liquid is dried in a vacuum drying oven at 333.15 K for 6 h; (2) Absorbing acetone; acetone enters from the bottom of the tower and comes into countercurrent contact with the absorbent entering from the top of the tower; (3) Changing the absorption conditions; wherein the specific conditions include: the water content of 1-butyl-3-methylimidazolium hexafluorophosphate and the inlet flow rate; (4) After the absorption is completed, the ionic liquid is released from the bottom of the tower and dried in a vacuum drying oven to achieve the regeneration of 1-butyl-3-methylimidazolium hexafluorophosphate.

[0010] As a further optimization of the method for efficiently absorbing acetone using imidazole ionic liquids of the present invention: considering the effect of temperature on absorption efficiency, the absorption temperature is determined to be room temperature.

[0011] As a further optimization of the method for efficiently absorbing acetone using imidazole ionic liquids of the present invention: considering the influence of the water content of the ionic liquid on the absorption efficiency, the water content of 1-butyl-3-methylimidazolium hexafluorophosphate is determined to be 90%.

[0012] As a further optimization of the method for efficient absorption of acetone using imidazole ionic liquids of the present invention: considering the influence of the inlet flow rate of the ionic liquid on the absorption efficiency, the inlet flow rate of 1-butyl-3-methylimidazolium hexafluorophosphate was determined to be 1000 mL / h.

[0013] As a further optimization of the method for efficiently absorbing acetone using imidazole ionic liquids of the present invention: considering the ionic liquid regeneration temperature as 333.15 K and the number of regeneration cycles as 5.

[0014] Beneficial effects

[0015] This invention uses imidazole ionic liquids as absorbents to achieve the absorption of acetone in an N2 environment. This method preferentially enriches acetone in imidazole ionic liquids, achieving an absorption efficiency of over 97%. By selecting N2 as the carrier gas, it simulates the scenario of acetone being emitted into the air, offering advantages such as high absorption efficiency, good separation performance, mild operating conditions, and a simple process flow. Attached Figure Description

[0016] Figure 1 This is a process flow diagram of an invention that utilizes imidazole ionic liquids for the efficient absorption of acetone. Detailed Implementation Example 1

[0017] A method for efficiently absorbing acetone using imidazole ionic liquids includes the following steps: 1-Butyl-3-methylimidazolium hexafluorophosphate was dried in a vacuum drying oven at 333.15 K for 6 h. The 1-Butyl-3-methylimidazolium hexafluorophosphate was then sprayed into the absorption tower from the top, coming into countercurrent contact with acetone gas entering from the bottom. The inlet flow rate of 1-Butyl-3-methylimidazolium hexafluorophosphate was adjusted to 200 mL / h, and absorption was carried out under ambient temperature and pressure. Subsequently, the absorbed ionic liquid was discharged from the bottom of the tower and placed in a vacuum drying oven for regeneration at 333.15 K. Online monitoring of the absorbed gas using gas chromatography showed that the absorption efficiency of acetone reached 44.39%, demonstrating high efficiency in acetone absorption. Example 2

[0018] A method for efficiently absorbing acetone using imidazole ionic liquids includes the following steps: The drying method for the imidazole ionic liquid used was the same as in Example 1. The water content of the ionic liquid during absorption was the same as in Example 1, and the feed rate of 1-butyl-3-methylimidazolium hexafluorophosphate was adjusted to 1000 mL / h. Absorption was performed using the imidazole ionic liquid under ambient temperature and pressure conditions. Subsequently, the absorbed ionic liquid was discharged from the bottom of the column and placed in a vacuum drying oven for regeneration at 333.15 K. Online monitoring of the absorbed gas using gas chromatography showed that the absorption efficiency of acetone reached 97.41%, indicating that the system has a high absorption efficiency for acetone at an ionic liquid feed rate of 1000 mL / h. Example 3

[0019] A method for efficiently absorbing acetone using imidazole ionic liquids includes the following steps: The drying method for the imidazole ionic liquid used was the same as in Example 1. The flow rate of the ionic liquid entering the column during absorption was the same as in Example 1, and the water content of 1-butyl-3-methylimidazolium hexafluorophosphate was adjusted to 90%. Absorption was performed using the imidazole ionic liquid under ambient temperature and pressure conditions. Subsequently, the absorbed ionic liquid was discharged from the bottom of the column and placed in a vacuum drying oven for regeneration at 333.15 K. Online monitoring of the absorbed gas using gas chromatography showed that the absorption efficiency of acetone reached 99.51%, indicating that the system has a high absorption efficiency for acetone under the condition of 90% water content in the ionic liquid.

Claims

1. A method for high efficient absorption of acetone using imidazolium ionic liquid, characterized in that, Including the following steps: (1) Drying the ionic liquid, wherein the absorbent is an imidazole ionic liquid, and drying it in a vacuum drying oven at 333.15 K for 6 h; (2) The ionic liquid and acetone are in countercurrent contact. 1-Butyl-3-methylimidazolium hexafluorophosphate enters from the top of the absorption tower, and acetone enters from the bottom of the tower. (3) Adjust the absorption conditions, which include: the water content of the ionic liquid; the flow rate of the ionic liquid into the tower; (4) Collect the absorbed ionic liquid and perform 5 cycles of regeneration experiment.

2. The method of efficiently absorbing acetone according to claim 1, characterized by, The absorbent is an imidazole ionic liquid, which is vacuum dried in a vacuum drying oven at 333.15 K for 6 h before use.

3. The method for efficiently absorbing acetone according to claim 1, characterized in that, The absorption conditions are normal temperature and pressure.

4. The method for efficiently absorbing acetone according to claim 1, characterized in that, The water content of the ionic liquid is 0-90%, preferably 90%.

5. The method for efficiently absorbing acetone according to claim 1, characterized in that, The flow rates of the ionic liquid entering the column are 200 mL / h, 500 mL / h, 800 mL / h, and 1000 mL / h, with 1000 mL / h being the preferred rate.

6. The method for efficiently absorbing acetone according to claim 1, characterized in that, The absorbed ionic liquid is recovered from the bottom of the column, and the cycle is repeated 5 times.

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