CO2 Capture From Sulfur Recovery Units’ Effluents

Dolphin Energy Limited (DEL) is considering reducing the native Greenhouse Gases (GHG) emissions from its Ras Laffan plant in the state of Qatar. One important source of native Carbon Dioxide (CO2) is the gaseous effluents from the two Sulfur Recovery Units (SRU’s). Dolphin studied the possible options for recovering up to 50 MMSCFD CO2 from the subject SRU’s effluents upstream the thermal incinerator section in the SRU using the existing infrastructures in its Ras Laffan plant. The recovered CO2 would be exported at medium pressure (MP, 7 bara) and/or high pressure (HP, 190 bara) to other users. The study investigated the possible options to recover and compress the CO2 product. Capital costs, utilities requirements, operating costs, carbon intensity savings, layout and electrical power supply were all studied. The study investigated the following technologies, which are based on amine solvents: • HP scheme with some feed gas compression to improve the performance of the solvent and reduce equipment size • LP scheme with low pressure efficient technology that does not need much feed compression • Revision of existing treatment scheme in the Sulfur Recovery Unit to perform Acid Gas Enrichment, Tail Gas Treatment and CO2 capture with minimum modifications The study considered that either (i) each SRU train will get its own CO2 recovery unit and compressors, or (ii) the SRUs’ effluents from both SRU trains will be combined before treatment. The paper will present main outcomes of this study and highlight specific requirements with regard to CO2 properties in terms of phase behavior, design criteria and Health, Safety and Environment.