This unit processes overhead gas and naphtha from the fractionators in the Hydrocracker Fractionation Unit and Delayed Coking Unit and also processes purge gas from the hydrogen purification Pressure Swing Adsorption Unit. Its purpose is the stabilization of the naphtha and the recovery of butane and heavier hydrocarbons for blending into the synthetic crude oil product. The feed gases are compressed, cooled and scrubbed successively with
naphtha and lean sponge oil which absorbs the butane and heavier hydrocarbons. The propane and lighter dry gas is amine treated to remove hydrogen sulphide. The sweet gas (1500 ppm H2S) is routed to the Upgrader fuel gas system where it is burned in the furnaces and boilers used in various process plants. The naphtha is debutanized to meet vapour pressure requirements and sent to the Naphtha/Jet Hydrotreater for further processing. A portion of the naphtha is recycled for use as lean adsorber oil.
Diagram used with permission (© SAIT Polytechnic, MacPhail School of Energy, 2009)