Used 7500 BPD Merox Unit from within a refinery, built in 1970. This Merox Unit is designed to remove Mercaptan Sulfur from the sour kerosene stream within the refinery to produce a sweet kerosene. Merox stands for MERcaptan OXidation unit. Mercaptan Sulfur are undesirable in kerosene. With this unit, raw kerosene is treated to convert it to Jet A1 Kerosene and sold as aviation fuel.
The raw kerosene first enters the Caustic Prewash Vessel, containing a diluted caustic solution used to remove naphthenic and aliphatic acids and any hydrogen sulfide that's present. The prewashed kerosene passes from the top of the prewash vessel to the sand filter, flowing down the top of the filter which coalesces any finely suspended caustic or neutralisation soaps in the kerosene. The haze-free kerosene leaves the sand filter at the lower nozzle and flows to the caustic settler, where any caustic carried over from the prewash vessel and sand filter settles to the base of the vessel. Treated kerosene flows from the caustic settler to the second sand filter through the top and flows downward, filtering any suspended caustic materials. The coalesced material settles to the bottom of the sand filter and the accumulated phase is periodically pressured to the spent caustic neutralizing pit. The treated kerosene leaves the Merox unit and into a storage tank or onto to other streams.