Swirling Element of Radiant Tube (SERT)

Cracking furnace is an important facility for production of basic petrochemical blocks such as ethylene and propylene. Feedstock through the tube in the furnace is heated and converted into desired products. In the industrial operation, heat resistance will build up in the tube due to the flow boundary layer and the formation of coke on the inside wall of the tube, thus resulting in over-temperature and shortened run length. The tube with twisted-tape technology developed by SINOPEC can intensify the heat exchange by reducing the heat resistance in the flow boundary layer and reduce coke deposition inside the tube.
The innovative tube is a precision cast tube integrated with inside twisted-tape, which is inserted into the reaction tube of the radiation section of cracking furnace. Passing through the twisted-tape, the flow in the reaction tube is forced to change from a plug flow to a swirl flow, which greatly increases the flow rate along the tube perimeter and forms a strong scouring force towards the tube wall. Thus, the thickness of the boundary layer decreases, the heat exchange coefficient increases and the temperature at the tube wall decreases, consequently leading to the decrease of coke formation at the wall and further improving the heat exchange coefficient, and resulting in the intensified heat exchange and a longer run length.