CRACKING TUBE WITH SPIRAL FIN

摘要

A cracking tube (50) used in a pyrolysis reaction furnace for manufacturing ethylene and the like, wherein fins (1) having an agitating effect on fluid in the tube are formed on the inner surface of the tube diagonally relative to the axis of the tube and intermittently in a spiral direction while drawing one to multiple lines of spiral tracks, and zones (ZB) in which the fins are absent on the inner surface of the tube are provided over the entire axial area thereof ranging from one end face of the tube to the other end face thereof.