Sulfatide formation in alkylation units
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How is sulfatide formation in alkylation units produced, and how can it be prevented?
In alkylation units, the formation of sulfates is primarily a problem related to side reactions; it is necessary to control the amount of impurities in the raw materials, such as butadiene, methanol, ethanol, ethylene, propylene, etc. Special attention must be paid to propylene； Next is the control of the reaction phase; some companies go to any length to increase the yield by raising the reaction temperature and the space velocity, which leads to acid migration and subsequently the formation of sulfates. I hope this can help you! If you want to know how to determine it, contact me!
The lipids involved in the alkylation reaction are alkyl sulfates formed from the olefins in the raw materials and sulfuric acid; most of these lipids are reaction intermediates. This esterification process is generally reversible, with the exception of dipropyl sulfate, which is produced from propylene and sulfuric acid, has stable properties, and is less prone to reverse reactions. Therefore, it is necessary to limit the amount of propylene in the raw materials. This is my own understanding; please correct me if I’m wrong.
Components below C3 are removed in the light-end stripping tower.
Impurities in the raw materials are the main cause of the formation of sulfates; this is primarily due to proper control of the operations in the washing towers, dehydrogenation towers, and hydrogenation units. Another reason is reactor overload
One more thing: the ratio of alkenes to olefins must be properly adjusted. Otherwise, sulfates will also be formed