PTQ Q4 2026 Issue

presence of H₂S and a range of organic sulphur-containing compounds including COS and mercaptans. A biorefinery implemented a conversion from DEA to one of Dow’s proprietary formulated solvent systems with the objective of resolving persistent non‑compliance with the green LPG copper strip corrosion test. Following the intro- duction of the solvent formulation, the unit consistently met the required copper corrosion specification. The improve- ment is reflected in the performance trend reported in Figure 5 . The refinery has no downstream caustic treating units, and the solvent change avoided the need to install additional treatment facilities. Case 5: Opportunity crudes A refinery located in Eastern Europe upgraded its LPG treating unit from MEA to a Ucarsol solution while the unit was still running. The change was needed because a new crude slate caused much higher mercaptan lev- els in the LPG, making it hard to meet product quality specifications. After the switch, the unit immediately reached the target of less than 200 ppm total mercaptans in the sweet LPG, achieving 80-92% removal when treating feeds containing 700-1,300 ppm. Conclusions The ongoing transformation of the refining industry, driven by stricter sustainability targets, digitalisation, effi- ciency requirements, cost reduction, and the shift towards

renewable and non-fossil feedstocks, demands a new approach to amine unit design and operation. Refinery treating systems are becoming more complex due to tighter sulphur regulations, LPG integration, discounted opportu- nity crudes, and renewable feedstock processing. A circuit-specific solvent strategy, embracing advanced formulations when needed, provides refineries with the flexibility required to handle higher CO₂ loads, minimise solvent losses, improve energy efficiency, ensure consist- ent removal of H₂S, mercaptans, and other evolving con- taminants and reduce negative impact on downstream units. Refineries can significantly improve unit performance by selecting solvents based on circuit requirements rather than applying a single universal solvent. Formulated sol- vents provide practical solutions to issues such as solvent losses, mercaptan removal limitations, and CO₂ absorption challenges, delivering improved reliability with no major capital investment.

UCARSOL Formulated Solvents is a mark of DOW.

Lorenzo Spagnuolo is a senior technical service and development sci- entist at Dow, focused on gas treating technologies for refining and natural gas applications. He is an oil and gas industry expert with 32 years of experience in gas plant process design, optimisation, opera- tions, and corrosion mitigation, starting his career in an Italian refin- ery, holding various positions. Spagnuolo holds a Master’s in chemical engineering from Sapienza Università di Roma, Italy.

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PTQ Q4 2026