Patent ID: 8501123

Claim:
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 having a vertically spaced lower end and upper end 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 and located at a level in the isostripper above the lower outlet, (iii) a fractionator tower having a vertically spaced lower end and upper end with the lower end at a higher temperature than the upper end, 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 above the lower end which is 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, a reboil circuit at the lower end of the tower to supply heat to the tower from an external source and a bottoms outlet for alkylate product and polymeric by-product ASO, the bottoms outlet being connected to the feed inlet of the isostripper.