Hydrocarbon conversion processes using mixed phase feed-streams - where heating to reaction temp. is effected in indirect heat exchanger

摘要

Hydrocarbon conversion processes are claimed in which a mixed-phase feed stream is heated to reaction temp. and partially vaporised by passage through an indirect heat exchange zone prior to passing to the reaction zone. The reaction effluent is separated into vapour and liquid phases and the liquid phase is heated by passage through a direct-fired heating zone to a temp. =15-20 degrees F above the temp. of the reaction zone inlet. Thereafter, the heated liquid phase is cooled by passing it through the indirect heat exchanger used in heating the original feed stream. Pref. at least part of the vapour-phase effluent is recycled to the reaction zone as part of the feedstream. The technique is claimed for use in the isomerisation of 7-9C aromatics or 4-7C n-paraffins, in hydroprocessing and in the hydrogenation of olefins, but is also disclosed to be applicable to non-catalytic conversion processes, such as the thermohydrodealkylation of toluene or visbreaking, and other processes, such as the dehydrogenation of 8-18C n-paraffins, etc. The problems associated with the maldistribution of mixed-phase feed stream in fired heaters are reduced.