US Patent 10188988 Claus unit treatment of shutdown tail gas

The process for configuring or reconfiguring a sulfur removal plant having a plurality of Claus units that is greater than the number of downstream tail gas treating units (TGTUs) allows for the regeneration of one of the Claus units without shutting down any of the downstream TGTUs or the other Claus units. Specifically, the regeneration tail gas can be diverted to the reaction furnace of an in-service Claus unit, thereby allowing excess oxygen to be used to regenerate the Claus unit more efficiently, and without exceeding environmental SO2 emission requirements.