Operational Validation of the SPREX~R Process for Bulk H2S Removal

摘要

Rising energy costs and growing demand for natural gas have driven the development of sour gas fields around the world. Because they account for approximately forty percent of the world's natural gas reserves, economical treatment of these "sour" gases, which may contain more than 20% acid gases (H2S and/or CO2), has become a major issue for the gas operators. Responding to this new challenge, Total, Institut Francais du Pétrole (IFP) and Prosernat have developed a cryogenic process for bulk H2S removal from very sour wet gases, the SPREX~R process. This original treatment allows substantial CAPEX and OPEX savings when the separated acid gases are reinjected. In order to prove and validate the viability of this innovative concept in an industrial context, a pilot unit was built and installed at Total's Lacq sour gas plant in France. It was started up in 2005, and its successful operation for more than 15 months has demonstrated the ability of the SPREX~R process to produce sour gases economically. After describing the SPREX~R pilot unit, this paper presents the main experimental results obtained during the campaign from March 2005 to June 2006. The operational feasibility of the process and its ability to remove H2S and H2O from raw natural gas efficiently are discussed in particular. The key parameters governing SPREX~R process performance as a function of the operating conditions are also characterized and studied. The data calculated by the modelling tool are then compared to the experimental results. This shows that the model developed at IFP to predict SPREX~R process performance is excellent. The accuracy of the modelling tool, in conjunction with operational data from the pilot tests, provides assurance that the design of future SPREX~R industrial units will be fully optimized. Indeed, the configuration and operating parameters of the SPREX~R process can be adapted to treat very sour gases economically in accordance with specifications requested by the operator.