A process for hydrogenation of a hydrocarbon stream comprising olefinic compounds, aromatic compounds or a combination thereof, comprising the steps of i) feeding the hydrocarbon stream and hydrogen into a first reaction zone of a hydrogenation process unit, ii) hydrogenating in the first reaction zone in the presence of a catalyst at least part of said aromatic compounds, olefinic compounds or combination thereof to produce a first intermediate, iii) cooling and separating said first intermediate into first intermediate liquid stream and first intermediate gas stream, iv) conducting the first intermediate gas stream to a second reaction zone of the hydrogenation process unit v) conducting said first intermediate liquid stream a) partly to the inlet of the first reaction zone as a liquid recycle stream in order to restrict the temperature rise in the first reaction zone to less than 60 °C, and partly b) either to the second reaction zone, wherein the remaining aromatic compounds, olefinic compounds or combination thereof contained in said first intermediate liquid stream are hydrogenated with the first intermediate gas stream in the presence of a catalyst to produce a saturated product, or c) to a liquid bypass line, which bypasses the second reaction zone, wherein said first intermediate liquid stream comprises a saturated product vi) separating the saturated product obtained from b) or c) into liquid product stream and a separated gas stream, vii) recovering the liquid product stream from the hydrogenation process unit, wherein said steps from i) to vii) within high-pressure section are conducted at a constant pressure selected from 2 - 8 MPa, preferably from 3 - 6 MPa, and wherein a device for implementing said process comprises a first hydrogenation reaction zone with at least one hydrogenation reactor, a second hydrogenation reaction zone with at least one hydrogenation reactor, a liquid recycle loop from a hot high-pressure separator to the inlet of the first reaction zone, means for conducting the first intermediate gas stream from said hot high-pressure separator to the second reaction zone, means for conducting at least part of the first intermediate liquid stream to the second reaction zone, a line for liquid bypassing the second reaction zone, a cold high-pressure separator and a gas recycle loop from the cold high-pressure separator to the inlet of the first reaction zone. i) feeding the hydrocarbon stream and hydrogen into a first reaction zone of a hydrogenation process unit, ii) hydrogenating in the first reaction zone in the presence of a catalyst at least part of said aromatic compounds, olefinic compounds or combination thereof to produce a first intermediate, iii) cooling and separating said first intermediate into first intermediate liquid stream and first intermediate gas stream, iv) conducting the first intermediate gas stream to a second reaction zone of the hydrogenation process unit v) conducting said first intermediate liquid stream a) partly to the inlet of the first reaction zone as a liquid recycle stream in order to restrict the temperature rise in the first reaction zone to less than 60 °C, and partly b) either to the second reaction zone, wherein the remaining aromatic compounds, olefinic compounds or combination thereof contained in said first intermediate liquid stream are hydrogenated with the first intermediate gas stream in the presence of a catalyst to produce a saturated product, or c) to a liquid bypass line, which bypasses the second reaction zone, wherein said first intermediate liquid stream comprises a saturated product a) partly to the inlet of the first reaction zone as a liquid recycle stream in order to restrict the temperature rise in the first reaction zone to less than 60 °C, and partly b) either to the second reaction zone, wherein the remaining aromatic compounds, olefinic compounds or combination thereof contained in said first intermediate liquid stream are hydrogenated with the first intermediate gas stream in the presence of a catalyst to produce a saturated product, or c) to a liquid bypass line, which bypasses the second reaction zone, wherein said first intermediate liquid stream comprises a saturated product vi) separating the saturated product obtained from b) or c) into liquid product stream and a separated gas stream, vii) recovering the liquid product stream from the hydrogenation process unit,