A process for producing a mixed feed stream for a steam reforming plant containing at least one reforming stage, comprising a first feed stream containing methane and a second feed stream comprising higher hydrocarbons, olefins and diolefins, wherein the first and/or the second feed stream also contains sulfur compounds, and wherein the process comprises the following steps: (a) providing the first feed stream and the second feed stream, (b) heating the first feed stream in a first heating device, (c) combining and mixing at least a part of the first feed stream with the second feed stream, introducing this mixture into a first hydrogenation zone, at least partly converting the diolefins in the first hydrogenation zone under diolefin hydrogenation conditions, discharging a diolefin hydrogenation product stream from the first hydrogenation zone, (d) introducing the diolefin hydrogenation product stream into a second hydrogenation zone, at least partly converting the olefins in the second hydrogenation zone under olefin hydrogenation conditions, discharging an olefin hydrogenation product stream from the second hydrogenation zone, (e) introducing the olefin hydrogenation product stream into a third hydrogenation zone, at least partly converting the sulfur compounds in the third hydrogenation zone under conditions of the hydrodesulfurization to desulfurized hydrocarbons and hydrogen sulfide, discharging an HDS product stream from the third hydrogenation zone, (f) introducing the HDS product stream into at least one adsorption zone, filled with an adsorbent selective for hydrogen sulfide, at least partly separating the hydrogen sulfide by adsorption on the adsorbent, discharging an adsorber product stream depleted of hydrogen sulfide from the adsorption zone, (g) introducing the adsorber product stream as mixed feed stream into at least one reforming stage, characterized in that - after heating in the first heating device, the first feed stream is split up into a first hydrogenation partial stream and a second hydrogenation partial stream, - the first hydrogenation partial stream is introduced into a cooling device, - a cooled first hydrogenation partial stream is discharged from the cooling device, - the cooled first hydrogenation partial stream is combined and mixed with the second feed stream, - the mixture thus obtained is introduced into the first hydrogenation zone. (a) providing the first feed stream and the second feed stream, (b) heating the first feed stream in a first heating device, (c) combining and mixing at least a part of the first feed stream with the second feed stream, introducing this mixture into a first hydrogenation zone, at least partly converting the diolefins in the first hydrogenation zone under diolefin hydrogenation conditions, discharging a diolefin hydrogenation product stream from the first hydrogenation zone, (d) introducing the diolefin hydrogenation product stream into a second hydrogenation zone, at least partly converting the olefins in the second hydrogenation zone under olefin hydrogenation conditions, discharging an olefin hydrogenation product stream from the second hydrogenation zone, (e) introducing the olefin hydrogenation product stream into a third hydrogenation zone, at least partly converting the sulfur compounds in the third hydrogenation zone under conditions of the hydrodesulfurization to desulfurized hydrocarbons and hydrogen sulfide, discharging an HDS product stream from the third hydrogenation zone, (f) introducing the HDS product stream into at least one adsorption zone, filled with an adsorbent selective for hydrogen sulfide, at least partly separating the hydrogen sulfide by adsorption on the adsorbent, discharging an adsorber product stream depleted of hydrogen sulfide from the adsorption zone, (g) introducing the adsorber product stream as mixed feed stream into at least one reforming stage, characterized in that - after heating in the first heating device, the first feed stream is split up into a first hydrogenation partial stream and a second hydrogenation partial stream, - the first hydrogenation partial stream is introduced into a cooling device, - a cooled first hydrogenation partial stream is discharged from the cooling device, - the cooled first hydrogenation partial stream is combined and mixed with the second feed stream, - the mixture thus obtained is introduced into the first hydrogenation zone. - after heating in the first heating device, the first feed stream is split up into a first hydrogenation partial stream and a second hydrogenation partial stream, - the first hydrogenation partial stream is introduced into a cooling device, - a cooled first hydrogenation partial stream is discharged from the cooling device, - the cooled first hydrogenation partial stream is combined and mixed with the second feed stream, - the mixture thus obtained is introduced into the first hydrogenation zone.