Abstract: A process for sweetening high mercaptan content gasoline or other liquid hydrocarbons is disclosed which utilizes aqueous caustic solution. A recycle stream is used to increase the conversion potential by reducing the relative mercaptan concentration of the untreated gasoline. Part of the treated gasoline effluent is recycled to the untreated feed. The treated gasoline has a low mercaptan concentration while the untreated gasoline is high in mercaptans. As the two streams combine, the feed to the unit becomes less concentrated in mercaptan compounds. In effect, the mercaptan concentration of the untreated gasoline has been diluted by the treated gasoline. Nitrogen inhibits the solubility of oxygen into gasoline. Nitrogen present in the recycle stream would create a system high in nitrogen and low in oxygen. By increasing the level of nitrogen, oxygen is limited in its ability to complete the sweetening reaction.

Abstract: A process for saturating aromatics in a lube range hydrocarbon is disclosed. The process can be used to raise the viscosity index of the lube range products. The process is carried out over a noble metal catalyst under mild process conditions. The catalyst is resistant to sulfur and nitrogen compounds.

Abstract: A hydrocarbon stream is washed with caustic solution to reactively remove hydrogen sulfide and produce a spent caustic solution containing sulfide reaction products. The spent caustic solution is stripped with concentrated carbon dioxide to reactively remove the sulfides and produce an overhead hydrogen sulfide stream and a bicarbonate-containing bottoms stream. The hydrogen sulfide stream can be converted to elemental sulfur in a Claus unit or to sulfuric acid in a sulfuric acid plant. The bicarbonate solution can be washed with liquid hydrocarbon to remove mercaptans and phenols in further preparation for disposal.

Abstract: The present invention is an automatic filter cleaning system which includes a solvent dewaxing filter which removes wax from a wax mix slurry and provides a filtrate. Status control apparatus is connected to the filter for affecting the operational status of the filter. Drain apparatus responsive to a control signal controls draining of the filter. Cleaning apparatus is also connected to the filter. A control network connected to the status apparatus, the draining apparatus and the cleaning apparatus controls those apparatus in a manner so as to allow selective changing of the status of the filter from an operational state to a down state to automatically drain the filter and clean the filter while the filter is in the down state.