Partners in Projet IGCC Normandie�a gasification project being developed by TotalFinaElf SA, Electricit�e France, and Texaco Inc.�have selected UOP LLC, Des Plaines, Ill., to supply the acid gas removal process for the gasification plant they will build in France's Normandy region. The license moves the project, slated to come on stream late in 2003, a step forward in more than one way. It uses an innovative design approach that improves environmental performance while optimizing plant operations.
The integrated gasification combined-cycle (IGCC) plant will be constructed on a site adjacent to TotalFinaElf's Gonfreville refinery. The IGCC plant will use Texaco's gasification process to convert high-sulfur, heavy fuel oil, used lube oils, petroleum coke, and wastes from the Gonfreville refinery to synthesis gas. The synthesis gas will drive a turbine that produces 365 Mw of electric power. The plant will also produce 250 tonnes/hr of steam and 50-100 tonnes/day of hydrogen.
Under this latest contract, the partners will use UOP's Selexol process to remove hydrogen sulfide (H2S) and other acid gases from the synthesis gas before it is sent either to the hydrogen purification unit or to the expander-turbine section for power generation. About 120 tonnes/day of elemental sulfur will be recovered from the plant.
Innovative design
Because the IGCC plant will use a variety of refinery waste streams as feed, UOP is designing the Selexol unit to process synthesis gases with varying hydrogen-to-carbon-monoxide ratios and impurity levels.
"The plant's overall high sulfur extraction will enable it to consistently meet environmental requirements," said UOP. One of the reasons for this high-sulfur extraction level, said the process licenser, is that a recycle stream of hydrogenated Claus tail gas will be combined with the feed gas to the Selexol unit.
UOP says this is an innovative approach: "The Selexol unit will produce an H2S-enriched acid gas stream to allow an optimal Claus sulfur removal operation while minimizing the CO2 slip to the Claus plant, keeping the kinetic energy from these molecules for power production.
"Extensive evaluation of alternative solutions by Projet IGCC Normandie revealed that applying conventional wisdom would not produce a cost-effective solution for the sulfur block," said the firm. "The system integration of the highly efficient, proprietary Selexol process scheme resulted in a less expensive Claus plant while also eliminating traditional processing units (tail gas treatment), with their added complexity, leading to a lower investment for the sulfur block."
The nature of the Selexol solvent will bring other benefits to the project, says UOP.
