PINNED FURNACE TUBES

摘要

Furnace tubes for cracking hydrocarbons having a longitudinal array of pins having i) a maximum height from 2 to 4.8 cm; ii) a contact surface with the tube, having an area from 0.1%-10% of the tube external cross section area iii) a uniform cross section along the length of the pin.(i.e. they are typically not tapered) ;and iv) a length to diameter ratio from 4:1 to 2:1 have an improved heat transfer over bare fins and reduced stress relative to a fined tube.