Chloromethane gas dehydration process in butyl rubber production process

Abstract

The invention discloses a chloromethane gas dehydration process in a butyl rubber production process, and belongs to the technical field of separation and purification. The method comprises the stepsof feeding an industrial material containing a certain amount of water into an absorption tower through a pipeline, wherein the operation conditions of the absorption tower are preferably as follows:the temperature is 25 DEG C, the absolute pressure is 4atm, and the number of theoretical plates is 6. The water content in the industrial material is 0.1%-2% (mass fraction, similarly hereinafter), the ionic liquid rich in water at the bottom of the tower firstly enters a first flash tank to remove most chloromethane contained in the ionic liquid, then enters a second flash tank to remove water contained in the ionic liquid, the ionic liquid extracted from the bottom of the second flash tank is recycled, and finally, the water content in the gas discharged from the tower reaches ppm level.

Description

technical field [0001] The invention relates to a methyl chloride gas dehydration process in the production process of butyl rubber. A single ionic liquid is selected as the absorbent. The cations of the ionic liquid can be imidazoles, pyridines, quaternary ammonium salts, etc., and the anions can be bistrifluoromethanesulfonimide, tetrafluoroborate, hexafluorophosphate, acetate, sulfuric acid diethyl ester etc. It belongs to the technical field of separation and purification. Background technique [0002] Industrially, methyl chloride is an indispensable solvent in the production of butyl rubber, and the water content in methyl chloride directly affects the quality of the final product. The dehydration process of methyl chloride in butyl rubber equipment usually adopts the method of adsorption of activated alumina to remove the water in wet methyl chloride, which can basically meet the production requirements, but the desiccant has a short service life, frequent regenerat...

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Problems solved by technology

[0003] In addition, there are many other dehydration methods reported in the literature, such as physical dehydration method: NaA molecular sieve is used to remove water in monochloromethane: the advantage is that the adsorbent can be regenerated and reused; the disadvantage is that regeneration generally uses high-temperature inert gas to heat the adsorbent to vaporize water Brought out, the residual material gas in the adsorbent is difficult to recycle, the pollution is large, and the regeneration energy consumption is high; the dehydration of triethylene glycol: the advantage is that triethylene glycol has high hygroscopicity, low vapor pressure, small regeneration loss, and the regeneration process does not need to introduce inertness Gas, less environmental pollution; disadvantages: triethylene glycol still has a certain saturated vapor pressure, which will cause certain losses; long-term operation is prone to oxidation reactions, generating acidic organic acids, which corrode equipment; triethylene glycol is easy to foam and needs to be added Defoamer, which increases the cost; the desorption tower is used in the regeneration process, and the mass transfer and diffusion efficiency of water from triethylene glycol is low. To achieve a better regeneration effect, the regeneration temperature is high (generally at 180 ° C), and the energy consumption is high.

In addition, the solubility of triethylene glycol to some gases is large, which increases the investment in regeneration process equipment, the regeneration process is complicated, and the operation is high.

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