The last decade has seen the initiation, start-up and ongoing development for major oil and gas production projects requiring processing of extremely sour gas. Projects in the UAE and CIS states (particularly Central Asia) require processing of well fluids containing up to 10 mole % CO2 and 23 mole % H2S, with the potential for future projects to see the H2S level increase further. These projects are being designed to treat and process flows of up to 1,000 MMscfd alongside production of oil and/or condensate, as well as NGL/LPG recovery. The world scale processing of sour gas leads to the largest ever sulphur plants installed, with total plant capacities up to 10,000 TPD of elemental sulphur. Kuwait with the Jurassic gas projects is embarking on major sour gas processing and is ideally placed to benefit from the experience and strategies developed in these mega projects.
This paper summarizes a selection of the key sour gas mega project metrics and outlines some of the areas where the very high H2S and organic sulphur content of the well fluid, and the high ambient temperatures, either impacted the design of the process units or required additional design features. The technical discussion in this paper uses information gained from Fluor's experiences on several sour mega projects and covers:
Inlet gas conditioning to ensure there is no hydrocarbon condensation during the gas treating step
Removal of H2S, CO2, COS, and mercaptans from the gas phase
Condensate/oil treating options for organic sulphur removal
The design of the world's largest Sulphur Recovery and Tail Gas Treating trains