Abstract: Vertical shell-and-tube, shell-and-plate and double shell U-tube are three typical types of heat transfer in the second stage of pyrolysis gasoline hydrogenation unit. This paper introduces the structural characteristics, industrial application and operation effect of these three types of heat exchangers, and compares them in terms of equipment cost, heat transfer performance under long-term operation, pressure drop changing trend, energy consumption and their cleaning and maintainability. It is concluded that double-shell U-tube type is the best structural type, which provides a reliable basis for the type selection of feed-effluent heat exchanger for the second stage pyrolysis gasoline hydrogenation unit.

Key words: pyrolysis gasoline, hydrogenation, two-stage feed-in and feed-out heat exchanger, long-time running