What are the main reasons? As far as I know, one of them is to prevent the vaporization of naphtha

Prevent oil from being carried in the circulating hydrogen, as well as solvent foaming, which could endanger the operation of the hydrogen circulation machine； It also helps to reduce light oil losses

Does high temperature cause the oil to enter the compressor along with the circulating hydrogen?

This portion of oil and gas will cool down in the buffer tank of the circulator and turn into a liquid; if not handled carefully, this liquid can easily be introduced into the circulator, leading to accidents

I agree with what was said above; at the same time, the temperature should not be set too low, as low temperatures increase the risk of foaming in the amine solution.

At high temperatures, some of the lighter components will be in gaseous form and mix with the recycled hydrogen that has been separated from the cold high-pressure stream, thereby leaving the cold high-pressure stream. These light hydrocarbons will revert to a liquid state when the temperature drops and the pressure increases downstream. Liquid hydrocarbons can cause foaming in the amine desulfurization tower used for recycling hydrogen; without such a desulfurization system, these liquid light hydrocarbons may end up entering the hydrogen recycling compressor. Whether it is a reciprocating or centrifugal compressor, it is very dangerous for the gas medium to contain liquid, as this can easily damage the compressor. Furthermore, even if this portion of light hydrocarbons is separated and recovered in the recycled hydrogen separation tank, there is still some loss; the small amount that remains unseparated enters the reactor along with the recycled hydrogen and reacts to form smaller hydrocarbon molecules, ultimately resulting in a decrease in the overall yield of liquid hydrocarbons