BT-12 Critical Heat Flux for Intube Boiling of Saturated Hydrocarbons: Review of Status and Proposed New Approach

J. W. Palen

In spite of the importance of critical heat flux in design of process vaporizers, this area of heat transfer has been neglected. There exist many empirical and semi-empirical methods for critical heat flux when boiling water in tubes, as spawned by nuclear safety research, but fired heaters are still designed by ""Kern Age"" rules of thumb.

This report reviews the status of critical heat flux correlations for boiling in vertical tubes, and recommends the Katto-Ohno method as most applicable for hydrocarbons. A new method was then developed which gives results similar to those of the Katto-Ohno method, but is much simpler and easier to adapt to new data. Data do not exist for hydrocarbons under realistic process conditions, and will be necessary for further progress in this area. Recommendations are given.