Scott Kagesjian, Nick Watts, Quinn Kotter - Wood / Amec Foster Wheeler USA Corp
This case study presentation will review the motivation for, and scope of a refinery Sulfur Recovery Unit/Tail Gas Treating Unit (SRU/TGTU) upgrade that accomplished numerous improvements. The refiner needed to increase the capacity of the unit to handle sulfur produced from upstream treating units that were being revamped. Lower atmospheric SO2 emission limits were also imposed by the regulatory body.
Designed originally with ineffective reheating schemes, sub-dew point operation in two of the Claus reactors, and excessively complex equipment and piping layout, the SRU equipment and piping were re-configured and re-rated for operation as a traditional Claus unit. The SRU and TGTU were debottlenecked to achieve a significant capacity increase while maintaining compliance with permitted environmental emission standards. Capability for low-level oxygen enrichment was included in the upgrade scope. Considerable simplification of the overall process layout was realized, which resulted in reduced unit pressure drop, improved control of critical process variables, and important reliability and safety improvements.
The presentation will also address the challenges presented in execution and installation of the revamp, operating experience of the revamped unit as documented by a complete unit performance test, and the performance of several new technologies employed within the SRU and TGTU.