High-efficiency low-scale polymerization inhibition process for extracting and separating C5 by DMF (Dimethyl Formamide) method

Abstract

The invention provides a high-efficiency low-scale polymerization inhibition process for extracting and separating C5 by a DMF (Dimethyl Formamide) method, and a used polymerization inhibitor is prepared from the following components in parts by mass: 100 parts of 4-hydroxy-TEMPO (Tetramethylpiperidinooxy), 60 to 100 parts of N, N-dimethylhydroxylamine, 70 to 90 parts of ethylene glycol di-tert-butyl ether and 70 to 100 parts of ethylene glycol diformate; a polymerization inhibitor only needs to be injected in front of DMF circulating solvent inlets of a first extraction tower and a second extraction tower respectively; the consumption of 4-hydroxyl-TEMPO in the polymerization inhibitor is low, but the byproduct yield of tar is not high, scaling is less and slow, and a filter is less and slow to block; and the maintenance period of the separation device can easily reach more than one year when the C5 raw material condition is better.

Description

technical field [0001] The invention belongs to the technical field of carbon five separation technology, and in particular relates to a high-efficiency, low-scaling and polymerization inhibition process for extracting and separating carbon five by DMF method. Background technique [0002] The C5 by-product in the pyrolysis process of ethylene production and the separation of isoprene, piperylene and dicyclopentadiene are important raw materials for rubber synthesis and organic chemical industry. The industrial separation methods containing carbon five of diolefins are mainly solvent extraction distillation methods, such as acetonitrile (ACN) method, N,N-dimethylformamide (DMF) method and N-methylpyrrolidone (MP) method , where the DMF method is more commonly used. [0003] The DMF method for extracting and separating C5 is also called GPI method, which was developed and industrialized by Zeon Corporation of Japan. The basic process and effect are as described in US3510405....

AI Technical Summary

Problems solved by technology

[0006] Our company invented CN111233612A, which is a high-efficiency polymerization inhibitor for extracting and separating carbon five by DMF method. The ratio is 100 parts of 4-hydroxy-TEMPO, 50-100 parts of ethylene glycol di-tert-butyl ether and 30 parts -60 parts; In the recent practice, this polymerization inhibitor is dissolved and diluted with DMF solvent of 3-10 times of quality, is made into polymerization inhibitor solution, then injects respectively the first extraction tower, the second extraction tower by metering pump continuous or intermittent mode The injection flow rate of DMF circulating solvent and polymerization inhibitor is about 0.020m% of the C5 feed flow rate of the first extraction tower and the second extraction tower; when the C5 raw material condition is good, the tar by-product is not large, and the scaling Slower, the filter plugging is slower; but because isopentenyne and 2-butyne are separated by being concentrated to more than 7m% at the top of the second analysis tower and the top of the second rectification tower respectively, there is a certain Potential safety hazard, also respectively in the reflux of the second desorption tower tower top, the second rectification tower tower top, respectively continuously injects this polymerization inhibitor, other polymerization inhibitors such as TBC (p-tert-butyl phthalic diphenol) reflux dissolving Diluent, so that the maintenance interval of the separation device can be extended to more than one year

In addition to the DMF solvent inlet of the first extraction tower and the second extraction tower, the injection position of the polymerization inhibitor is also the top of the second analysis tower and the top of the second rectification tower. The continuous filling position, the batching and control are more cumbersome

Images