Abstract: Process flow sequences for the reduction of equipment fouling in the fractional distillation of light end hydrocarbon components, such as those produced by pyrolysis or steam cracking, wherein conventional multiple hydrogenation unit configurations are replaced with upstream hydrogenation unit configurations. The upstream hydrogenation units of the invention are located at either side draws or in the reboiler circuit of deethanizers, in front-end demethanizer and front-end deethanizer sequences, or depropanizers, in front-end depropanizer sequences and obviate the need for most of the conventionally used hydrogenation units downstream.