NOVELTY - Alkylation process involves regenerating used catalyst comprising an ionic liquid catalyst and chloride from an alkylation reactor (300) in a hydrogenation reactor (100), separating at least a portion of the obtained regenerated catalyst effluent (10) into a gas fraction comprising hydrogen gas (20), and light hydrocarbon fraction comprising hydrogen chloride (30), recycling at least a portion of the gas fraction to the hydrogenation reactor, and recovering and recycling at least the amount of the light hydrocarbon fraction to the alkylation reactor.    USE - Alkylation process used for producing alkylated product e.g. alkylated aromatic and alklyated isoparaffin. Uses include but are not limited to gasoline blending component, intermediate distillate, base oil and petrochemical component.    ADVANTAGE - The alkylation process is carried out economically and efficiently. The hydrogen chloride recovery in ionic liquid alkylation plant using hydro-regeneration of the ionic liquid catalyst is improved.    DETAILED DESCRIPTION - Alkylation process involves regenerating used catalyst comprising an ionic liquid catalyst and chloride from an alkylation reactor in a hydrogenation reactor to produce regenerated catalyst effluent, separating at least a portion of the regenerated catalyst effluent into a gas fraction comprising a hydrogen gas, and light hydrocarbon fraction comprising a hydrogen chloride, recycling at least a portion of the gas fraction to the hydrogenation reactor, recovering at least an amount of the light hydrocarbon fraction and recycling the at least the amount of the light hydrocarbon fraction to the alkylation reactor. An INDEPENDENT CLAIM is included for alkylation process unit, which consists of hydrogenation reactor, fractionation unit (200) which is connected to the hydrogenation reactor and which separates at least portion of the regenerated catalyst effluent into gas fraction and light hydrocarbon fraction, primary connection component provided between the fractionation unit and hydrogenation reactor for transmitting at least a portion of the gas fraction to the hydrogenation reactor, and secondary connection component provided between the fractionation unit and alkylation reactor to transmit at least an amount of the light hydrocarbon fraction to the alkylation reactor.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of the alkylation process unit.    Regenerated catalyst effluent (10)    Gas fraction comprising hydrogen gas (20)    Light hydrocarbon fraction comprising hydrogen chloride (30)    Off-gas (50)    Ionic liquid catalyst stream (60)    Hydrogenation reactor (100)    Fractionation unit (200)    Alkylation reactor (300)    Separator (400)