To process "cleaner," low-sulfur fuels, refiners must balance treatment against hydrogen consumption. In this example, the refiner must consider how to manage a hydrogen recycle stream from a diesel hydrotreater at a 215,000-bpd facility. The refinery needs to install a hydrogen plant, hydrotreater and sulfur recovery plant ( Fig. 1.)
Traditionally, amine-treating units can effectively remove hydrogen sulfide (H2S) from the hydrotreater hydrogen recycle streams. A separate purge then removes light hydrocarbons. New processing methods that use a nonaqueous scrubbing solution can remove both H2S and light hydrocarbons from recycle streams without a separate purge stream. The net effect is that of having a sponge-oil system that also recovers sulfur.