Abstract
In line with ADNOC Sustainability policy, reduction of GHG emissions, AGP has initiated projects for recovery of CO2 from existing plants. The extracted CO2 is planned to be used for Enhanced Oil Recovery. The current paper highlights method used for evaluation of various location and technology options for implementation of the new CO2 recovery units, considering existing plants flow schemes along with their interfaces and associated challenges.
Key Performance Indicators (KPIs) were identified based on Inherent Safety, Economics, Technology Maturity, Product Quality, Operability / Flexibility, Constructability. Identified options were further developed and subsequently evaluated based on preliminary economic analysis and available technical information. Accordingly, weighted scores of the KPIs developed for option selection. Major criteria used for ranking were unit cost of CO2 product, adherence to required H2S and COS specifications, technology maturity and deployment in industry.For one location, the options considered included installation of new Acid Gas Removal Unit (AGRU) upstream of existing AGRU, revamp of existing Acid Gas Enrichment Unit (AGEU), new AGEU, and direct feed of Acid gas to new CO2 recovery unit to supplement falling upstream reservoir profile.For another location, the options included new CO2 recovery plant upstream of existing Sulphur Recovery Unit (SRU) or downstream of existing Tail Gas Treatment Unit (TGTU), compression of TGTU gases upstream of proposed CO2 recovery unit, installation of new unit downstream of existing incinerators, combination of CO2 recovery units of both plants, were also assessed.In addition, new CO2 Dehydration and Compression units considered to meet CO2 product specifications and B/L requirements.
Based on project requirements, physical methods of CO2 removal like membranes and molecular sieves deemed unsuitable. Further to discussions with various licensors, emphasis remained on chemical and physical solvent technologies. Based on assessment, solvent swap for AGEU (upstream of existing SRUs) with reduced lean solvent temperature at one location, solvent swap in TGTU followed by a new polishing unit at another location combined with common high pressure compression facility, was selected for engineering development.