The effect of teflon on the condensation of benzene on a horizontal copper tube

The condensation of benzene vapor at atmospheric pressure was used to determine the effect of a thin coating of Teflon on the vapor-side heat transfer characteristics of a horizontal copper tube.

The condenser consisted of a three-foot length of 3.5 inch diameter iron pipe containing 0.4999 inch outside diameter copper tubing with 0.028 inch thick walls.

Experiments with the uncoated tube resulted in vapor-side coefficients about half as large as the Nusselt values. Teflon-coated tube coefficients were slightly higher than the uncoated tube results, but were still less than half of the Nusselt values.

From the results and equipment of other investigators, air in the condenser was considered the most probable cause of the low observed vapor-side coefficients, Equipment and procedure modifications were recommended to assure removal of air from the system. A different type of Teflon was recommended to remove temperature and organic vapor limitations.