BT-32 Vaporization of Light Hydrocarbons from Nonvolatile Components

L. Huang
2005; rev 10/2005

Accurate prediction of boiling heat transfer coefficients for vaporizing light hydrocarbons from a nonvolatile component remains challenging. HTRI recently conducted extensive experimental research with n-pentane/1-tetradecene and n-pentane/polybutene mixtures as test fluids. The data cover wide ranges of liquid Reynolds numbers, Prandtl numbers, weight fraction vapor, heat fluxes, and concentrations of n-pentane. In addition to expanding our data bank, we can now provide better guidelines and methods for rating or designing heat exchangers using such mixtures.

Our recent studies show that the dominant boiling mechanism for such mixtures is convective boiling. The n-pentane/polybutene data also indicate that mass transfer resistance for convective boiling is a strong function of liquid viscosity. We developed a new mass transfer coefficient correlation for the convective boiling mixture correction factor using the bulk vapor-to-liquid viscosity ratio, making concentration and liquid diffusivity information optional entries. We also discovered that a Prandtl number correction to the two-phase convection factor was necessary for fluids with large Prandtl numbers.