Catalytic distillation selective hydrogenation process for cracking petroleum hydrocarbon vapor for producing C3 fraction composition

The invented petroleum hydrocarbon steam cracking C3-fraction catalytic distillation selective hydrogenation process is to take material containing C3 and higher components and hydrogen to proceed hydrogenation in catalytic distillation tower, the selective hydrogenation catalyst used in catalytic distillation tower is directly spread on the catalyst bed lager, the free space exists inside the catalyst particle or/and between the particles, and the free space in the catalyst bed layer occupies 35-80% of the catalyst bed layer volume. The catalyst possesses dual functions of catalysis and fractionation, and it is high in reaction efficiency, no special internal is needed in reaction section, high in utilization rate of equipment, easy loading and unloading of catalyst, and long in service period.