HF alkylation process with internal acid regeneration

An HF alkylation unit used for the production of gasoline boiling range alkylate product by olefin/iso-paraffin alkylation, comprising:

• (i) an alkylation reactor with an associated acid settler having an upper outlet for alkylate and a lower outlet for HF alkylation acid and an associated HF alkylation acid circuit for supplying HF alkylation acid to the reactor,
• (ii) an isostripper for separating isoparaffin from alkylate product by fractionation to produce an isoparaffin overhead stream at an overhead outlet and an alkylate product stream as a bottoms fraction at a lower outlet, the isostripper having a feed inlet connected to the upper outlet of the settler,
• (iii) a fractionator tower having an inlet connected to the lower outlet of the settler to receive a slipstream portion of the HF alkylation acid circulating in the unit, an inlet connected to the lower outlet of the isostripper to receive a slipstream portion of the alkylate bottoms stream from the isostripper, an overhead outlet for fractionated HF alkylation acid and trace water and a bottoms outlet for alkylate product and polymeric by-product ASO, the bottoms outlet being connected to the inlet of the isostripper.