As environmental SO2 emission regulations become more stringent, Tail Gas Treating options become limited while solely catalyst-based TGT options are eliminated. To achieve lower OPEX, utilizinfg a biological desulfurization process as an alternative to a conventional amine-based TGT unit is becoming of increased interest in the Oil & Gas Industry during this energy transition era. At the same time, demands for increased SRU capacity and reliability favor the use of medium and high-level oxygen enrichment.

Fluor recently evaluated revamp options for an existing refinery with Air Operated 3 x 100 TPD SRUs. Fluor’s COPE II Oxygen Enrichment technology was selected to increase each train capacity to 150 TPD, essentially providing the equivalent redundancy of a spare train. The existing trains have insufficient tail gas treating to achieve an environmental emission specification below 150 mg SO2 /Nm3. Thiopaq O&G (TOG) and Thiopaq O&G Ultra (TOG Ultra), bio-desulfurization technologies developed by Paqell, can comfortably achieve an H2S treated gas specification of <25 ppmv in low pressure units.

A case study will be presented comparing the use of TOG (Ultra) in lieu of a conventional amine-based TGTU, including comparison of CAPEX and OPEX for both 55% O2 Enriched and Air Operated Claus/Thiopaq and Claus/Amine options. The case study shows that TOG (Ultra) options provide cost effective Tail Gas Treating alternatives to achieve emissions lower than the World Bank Standards for SRU facilities. Moreover, avoiding amine manufacturing provides a low carbon emission facility during this energy transition era. TOG options also de-bottleneck the SRU capacity by eliminating the tail gas recycle to the thermal reaction furnace.

Source: Paqell and Flour