High sulfur content in isooctane
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What is the reason for the high sulfur content in isooctane during the initial stage of alkylation unit startup? What’s the solution?
The alkylated feedstocks mainly consist of C4 and C5 olefins in liquefied petroleum gas components. These feedstocks likely contain relatively high amounts of sulfides carried over from upstream processes, where the desulfurization of liquefied petroleum gas fails to meet standards. However, since sulfuric acid is used as a catalyst in alkylation, the presence of sulfides does not affect the catalytic effect, but it does influence the total sulfur content in the resulting gasoline. Conduct sulfide analysis on upstream raw materials to determine the type of sulfur, and intensify the desulfurization process for liquefied gas.
During the initial startup of the unit, pay attention to the temperature of the caustic wash water. Take a look at this post: http://bbs.hcbbs.com/thread-1773028-1-1.html
At the beginning of operation, the reaction time is long and there are many side reactions, which are the main reasons for the high sulfur content in isooctane
This needs to be analyzed from several aspects: raw materials, reaction, and alkali washing and rinsing