Study of the Ways of Purifying the High-Sulphur Isopentane Fraction to Produce Isopentane Solvent

Abstract

The results of the application of a set of methods for purifying the isopentane (I), which enters the hydrogenation unit of a plant for producing
isopentane solvent, from sulfur compounds are presented. This has resulted in the extension of the hydrogenation catalyst life («run») by
reducing the mass share of total sulphur (S) content in the process of flow to the catalyst. The fraction of I with S content greater than 0,003
% (wt) was investigated. S content was determined by the optical density of the solution obtained by burning and dissolving sulphur oxide,
using a photocolorimeter of the CFC-3 model. In order to increase the length of one «run» and the service life of the catalyst as a whole, it
is also proposed to increase the alkali content from 0,1 to 0,9–1,0 % (wt) in the reaction mass in unit of the chemical purification of I from
cyclopentadiene, which makes it possible to reduce the S content, from 0,006–0,010 to 0,001–0,003 % (wt). The output of bottom liquid from
the rectification column also makes it possible to reduce the S content in the process flow, which is entered to the further purification of I. This
research provide the possibility to reduce S content in the raw I entered for the hydrogenation of acetylene hydrocarbons, and result in the
extension of the hydrogenation catalyst life.