When alkylating segregated olefin feeds, the optimum acid settler configuration will depend on the olefins processed and the relative rates of each type of feed. Generally, DuPont recommends processing the propylene in the high strength Contactor reactor, butylenes in the intermediate reactor and amylenes in the low strength reactor (Figure 7). The optimum configuration for a particular unit may involve operating some reaction zones in parallel, then cascading to additional reaction zones in series. DuPont considers several acid staging configurations for every design in order to provide the optimum configuration for the particular feed.