Method for purifying HF catalyst in an isoparaffin-olefin alkylation

In an olefin and isoparaffin alkylation process employing an HF catalyst, in which effluent from a reaction zone is passed to a settling zone to separate an acid stream containing HF and acid soluble oil which stream is then purified by separating the HF and acid soluble oil by a process comprising the steps of:

• a. introducing said acid stream into the intermediate region of an upper chamber of a purification column, said column comprising said upper chamber and a lower leg in communication with said chamber;
• b. introducing the isoparaffin as a liquid into an upper region of said chamber as a reflux;
• c. introducing the first portion of vaporous isoparaffin into said lower region of a leg, said vaporous isoprafffin flowing upwardly through said leg and said upper chamber to strip HF from said acid stream
• d. intimately contacting said first portion of vaporous isoparaffin with acid soluble oil collected in said leg;
• e. introducing a second portion of said vaporous isoparaffin into an eductor positioned at the bottom of a stand pipe in said leg to provide circulation of acid soluble oil upwardly therethrough and back into said leg;
• f. removing a stream containing vaporous isoparaffin and purified HF from the top of said upper chamber;
• and
• g. recovering acid soluble oil substantially free of entrained HF from the lower portion of said leg.