Alkylation is a combining process that creates alkylate, a premium, high-octane blending stock. A large acid settler tank within the unit allows for separation of the acid/hydrocarbon emulsion created in the reactor. Sight glasses have traditionally measured settler level, but these are susceptible to plugging and require diligent flushing at regular intervals.
Interface level control of the settler is required. Product/acid cross-contamination causes overall efficiency problems and can result in hazardous conditions. Inaccurate settler level indication is a frequent cause of physical acid carryover in the reactor effluent. Release of acid can cause extreme hazards to both process and personnel.