Process method for recycling acetone from exhaust gas

Abstract

The invention relates to a process method for recycling acetone from exhaust gas. The process method comprises the steps: firstly, the to-be-treated gas containing trace acetone is absorbed by absorption water in an absorption tower, then the diluted acetone water obtained at a tower bottom is separated in a liquid-liquid phase separator, one stream of the material liquid obtained from separation and having high acetone mass fraction is subjected to pressure reduction by a pressure reducer and then goes into a distillation tower for reduced pressure distillation, and the acetone product is extracted from a tower top. The process method improves the work efficiency and stability, can greatly reduce the energy consumption of the acetone recovery process, and has significant practicability and economic benefits.

Description

technical field [0001] The invention relates to the technical field of recovering untreated gas, in particular to a process for recovering acetone from untreated gas produced from cellulose acetate tow for cigarettes. Background technique [0002] Acetone is a good organic solvent in chemical production process, especially in pharmaceutical industry and cellulose acetate industry. Since acetone has a relatively low boiling point and strong volatility, acetone vapor is mixed with air during the production of cellulose acetate tow for cigarettes to form a gas containing a small amount of acetone, which needs to be recovered and purified. Since the content of acetone in the gas to be treated is very low, about 0.0179%, it is relatively difficult to recover and purify acetone in industry. At present, water absorption method and activated carbon fixed bed adsorption method are mostly used to recover acetone in gas. The water absorption method uses the property that acetone is v...

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Problems solved by technology

However, there are many disadvantages in the process of recovering acetone by activated carbon fixed bed adsorption: (1) the operation of the activated carbon adsorption process is intermittent, and the stability is relatively poor; (2) the analysis process needs to consume a large amount of steam, and the heat utilization rate is low, making The cost is high; (3) If the analysis process is not complete, it may cause the activated carbon to catch fire, and there are certain safety hazards; (4) The material transportation and absorption processes are all operated in a gaseous state, and there is a risk of explosion

[0003] Although the recovery of acetone by the water absorption method in the original process is continuous, the process is stable, safe and reliable, the energy consumption of the recovery of acetone by the water absorption method is relatively large.

There are two main reasons why the energy consumption of acetone recovered by the water absorption method in the original process is large: one is that the dilute acetone formed after the absorption of trace acetone by water contains less acetone in the water, with a mass fraction of 3.5% to 4.2%. It directly enters the distillation tower for distillation, which causes a great load to the distillation tower; second, the recovery of acetone by the original process water absorption method is mostly operated under normal pressure, and the relative volatility between its components is small, and the separation is relatively difficult, requiring a large reflux flow rate. Separation requirements can be achieved with the same number of plates

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