A method for reducing VOC content in tail gas produced by methane chloride device

Abstract

The invention provides a method for reducing the VOC content of tail gas produced by a methane chloride device. The method comprises the following steps: the tail gas generated by the methane chloridedevice is introduced from the medium-lower part of a spray absorption tower, and an absorbent is sprayed from the top of the spray absorption tower to absorb VOCs in the tail gas, except hydrogen chloride; the obtained unabsorbed tail gas enters a tail gas buffer tank from the top of the spray absorption tower; the obtained absorbent-rich solution undergoes heat exchange, and then enters a desorption tower through the top to desorb the VOCs in the absorbent-rich solution; the desorbed VOCs overflow from the top of the desorption tower, and enter an organic buffer tank for recycling; and an adsorbent-leach solution obtained after the desorption is discharged from the bottom of the desorption tower by using a pressure difference, is condensed, and enters the spray absorption tower through the top for cycle use. The method effectively realizes the reduction of the VOC content of the tail gas produced by the methane chloride device, and also realizes the recycling of materials in the tailgas in order to ensure the maximum benefit of running of the device.

Description

technical field [0001] The invention relates to a tail gas treatment method, in particular to a method for reducing the VOC content in the tail gas produced by a methane chloride device, and belongs to the technical field of environmental chemical industry. Background technique [0002] In recent years, the situation of air pollution in my country has become increasingly severe, and the emission of volatile organic compounds (VOC) has seriously affected the quality of ambient air. The World Health Organization defines VOC as: a compound with a boiling point of 50-250 ° C, a saturated vapor pressure exceeding 133.32 Pa at room temperature, and a class of organic compounds that exist in the air in the form of vapor at room temperature. [0003] At present, a large amount of tail gas will be produced in the production process of methane chloride, and the main components include hydrogen chloride, methyl chloride, methylene chloride, chloroform, carbon tetrachloride and other or...

AI Technical Summary

Problems solved by technology

Chinese patent document CN 203816452U discloses a system for processing the by-product tail gas of methyl chloride production, including a feed heat exchanger and a purification tower, and a cooling device is arranged at the top of the purification tower; After cooling, it enters the purification tower for condensation, hydrogen chloride gas is extracted from the top of the purification tower, and the chlorine-containing components other than hydrogen chloride are condensed and then discharged with the still liquid; this utility model uses condensation to separate the reaction tail gas mixture, and hydrogen chloride gas can be obtained directly, but The patent does not mention a device for further treating the by-product tail gas of methyl chloride, and it is only used for the tail gas of chlorine-containing components and hydrogen chloride, and there is also the problem of insufficient condensation that makes chlorine-containing components mixed into hydrogen chloride; Chinese patent Document CN201551948U discloses a methane chloride generation tail gas absorption device, comprising a falling film absorption tank, the falling film absorption tank is connected with the methane chloride generation tower through the first pipeline, and the absorption liquid pipe and the first outlet pipe are installed on the falling film absorption tank. The liquid pipe, the falling film absorption tank communicates with the tail gas absorption tower through the second pipeline, the upper part of the tail gas absorption tower is equipped with a spray pipe, the spray pipe is connected with the water source through the water pipe, and the second liquid outlet pipe is installed at the lower part of the tail gas absorption tower; the utility model Two-stage absorption is adopted, although it can fully absorb the chloride in the tail gas, but the utility model has two types of absorption liquid, and the amount is large, and the recovery and reuse are cumbersome, and the patent mentions the use of 22% hydrochloric acid and water to absorb by-products Tail gas can realize the absorption of hydrogen chloride and most of the chlorine-containing organic compounds, and the absorption liquid obtained by absorption contains hydrochloric acid and chlorine-containing organic compounds, resulting in difficult separation and low utilization rate of the absorption liquid, and does not involve the reuse of the absorption liquid

[0005] The biological purification method requires a continuous and stable air flow, and the operation stability is poor, while the exhaust gas generated by the device is intermittent and uncontrollable; in addition, the stability of the biological purification system will be affected during the shutdown of the device, and the biological purification system is running. It also requires huge operating and management costs

The catalytic oxidation method can realize the effective utilization of methyl chloride in the tail gas, but the tail gas contains other impurity gases, which will cause certain damage to the catalyst, reduce the life of the catalyst, and increase the operating cost of the whole set of equipment

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