Successful Troubleshooting to Improve RFCC LPG Amine Absorber Performance

Abstract LPG Amine absorbers are being used for removal of H2S from RFCC LPG stream prior to process in downstream LPG MEROX unit. The underperformance of the LPG amine absorber has adverse impact on downstream unit operation and meeting product specification. Since commissioning of RFCC Unit, LPG product was observed to be consistently off spec with respect to H2S content (>100 ppm against the design of 10 ppm). This high H2S slippage was severely impacting the Refinery operation as below, High caustic consumption in downstream LPG Treating unit & impacting Spent Caustic Treatment unitOff spec LPG product with respect to Disulphide content from LPG Treating UnitRFCC LPG product was not meeting the intermediate LPG sphere storage criteria of H2S content <50 ppm. In order to troubleshoot and identify the possible reasons for high H2S slippage from LPG Amine Absorber, a team was formed comprising of representatives from various dicipilne and agencies. Systematic way of troubleshooting was adopted with several brainstorming sessions between all the stakeholders. Following actions points evolved out of brainstorming session, Review column operating conditions for any deviation from design operating conditionDesign review of the column internals Based on in-house simulation and design review of LPG amine absorber, it was observed that existing column internals were inadequate to avoid mal-distribution and the same was deliberated in details with Licensor. Licensor concurred with the findings and packing vendor was engaged for further review. Column internals (Packing, Disperser plate and Distributor) has been redesigned and replaced with new internals. After replacement of column internal LPG product H2S content was observed to be within product specification.