A process and system for treating a hydroprocessing unit effluent gas stream for recycling includes introducing the effluent gas stream into a hydrogen purification zone and recovering a hydrogen-rich gas stream and a liquid stream containing a mixture that includes C1 to C4 hydrocarbons and H.sub.2S which is then mixed with an oxidant and fed to an oxidation unit containing catalyst for conversion of the H.sub.2S to elemental sulfur vapors that is separated for recovery of the elemental sulfur, and recovering a sweetened mixture that includes C1 to C4 hydrocarbons. Alternatively, the hydroprocessing unit effluent gas stream containing H.sub.2S is cooled, contacted with a solvent to absorb the C1 to C4 hydrocarbons and H.sub.2S, with the hydrogen-rich stream being recovered for recycling to the hydroprocessing unit, and the rich liquid solvent being flashed to produce a lean solvent stream for recycling to the adsorption zone and a mixed gas stream that includes the C1 to C4 hydrocarbons and H.sub.2S that is passed to an oxidation zone and is reacted with an oxidant in the presence of a catalyst to complete the process as described above for the recovery of elemental sulfur and a mixture that includes the sweetened C1 to C4 hydrocarbons.

The invention is an integrated process for treating residual oil of a hydrocarbon feedstock. The oil is first subjected to hydrodemetallization and then gas phase oxidative desulfurization. Additional, optional steps including hydrodesulfurization, and hydrocracking, may also be incorporated in to the integrated process.

The invention is an integrated process for treating residual oil of a hydrocarbon feedstock. The oil is first subjected to hydrodemetallization and then gas phase oxidative desulfurization. Additional, optional steps including hydrodesulfurization, and hydrocracking, may also be incorporated in to the integrated process.

The invention is an integrated process for treating residual oil of a hydrocarbon feedstock. The oil is first subjected to hydrodemetallization and then gas phase oxidative desulfurization. Additional, optional steps including hydrodesulfurization, and hydrocracking, may also be incorporated in to the integrated process.

The invention is an integrated process for treating residual oil of a hydrocarbon feedstock. The oil is first subjected to hydrodemetallization and then gas phase oxidative desulfurization. Additional, optional steps including hydrodesulfurization, and hydrocracking, may also be incorporated in to the integrated process.

The invention is an integrated process for treating residual oil of a hydrocarbon feedstock. The oil is first subjected to solvent deasphalting then gas phase oxidative desulfurization. Additional, optional steps including hydrodesulfurization, and hydrocracking, may also be incorporated into the integrated process.

The invention is an integrated process for treating residual oil of a hydrocarbon feedstock. The oil is first subjected to delayed coking and then oxidative desulfurization. Additional, optional steps including hydrodesulfurization, and hydrocracking, may also be incorporated in to the integrated process.

An oxidative treatment process, e.g., oxidative desulfurization or denitrification, is provided in which the oxidant is produced in-situ using an aromatic-rich portion of the original liquid hydrocarbon feedstock. The process reduces or replaces the need for the separate introduction of liquid oxidants such as hydrogen peroxide, organic peroxide and organic hydroperoxide in an oxidative treatment process.

An oxidative treatment process, e.g., oxidative desulfurization or denitrification, is provided in which the oxidant is produced in-situ using an aromatic-rich portion of the original liquid hydrocarbon feedstock. The process reduces or replaces the need for the separate introduction of liquid oxidants such as hydrogen peroxide, organic peroxide and organic hydroperoxide in an oxidative treatment process.

The present invention discloses a process for enhancing quality of a hydrocarbon stream. More particularly, the present invention discloses a process for improvement of the combustion quality of a diesel range stream by dissolving an oxygen source in the feed stream before carrying out the oxidation, thereby enhancing the Cetane number, lubricity and reducing emission of the stream. The present invention also discloses a process for enhancing combustion quality of a hydrocarbon stream by carrying out the process in presence of an organometallic catalyst.