Azadeh Mirvakili

Sulphur compounds and mercaptans in gas condensate cause corrosion problems, poison catalysts in catalytic processes, and have adverse environmental impact through SOx emission upon combustion. Therefore, it is essential to remove sulphur and mercaptan from gas condensate to standard levels. In this study, the oxidative desulphurization (ODS) process in the presence of a cobalt phthalocyanine sulfonamide-based catalyst was investigated. The homogeneous catalyst containing 23 wt.% active material was used and optimum operating conditions of temperature, volume ratio of caustic to gas condensate, caustic concentration, and solvent amount were determined to decrease sulphur content to less than 500 ppm and mercaptan to less than 200 ppm. The catalyst consumption in all experiments was kept constant at a minimum level (0.01 g/400 mL gas condensate). Results showed that this catalyst improved the reaction rate in the lower emperature and lower caustic to feed ratio and lower caustic concentration. The maximum sulphur removal was obtained at 5
C and 4 vol.% of caustic to gas condensate ratio at 16.7 wt.% of caustic concentration. Moreover, this catalyst improved sulphur removal from the gas condensate to about 5% compared to caustic sweeting without catalyst. Sulphur compounds had higher solubility in acetone rather than methanol, and sulphur removal by acetone was 96% while it was 91% for methanol. Finally, the economical and acceptable solvent for sulfoxides removal was methanol with 5% volume fraction