Experimental measurements are presented for the nucleate boiling of benzene, diphenyl, and benzene-diphenyl mixtures on a 3/8-in. od horizontal tube. The data were obtained in a pool boiling apparatus at pressures ranging from 13.5 to 488.5 psia. For the pure fluids, the nucleate boiling heat-transfer data were best correlated by the Rohsenow [12], Gilmour [8], and Levy [10] equations. Critical heat flux data reported for these fluids are correlated with those in the literature. The critical heat flux values for the pure fluids were best correlated by the Bernath relationship [1]; however, none of the literature expressions adequately predicted the large increases in critical heat flux that were obtained when small percentages of benzene were added to diphenyl. Similar increases in critical heat flux, when small amounts of volatile components are added, have been noted before, but no generalized correlations have been advanced. Some of the discrepancy may be due to inadequate knowledge of physical property data for the mixtures and failure to account for the mass transfer which occurs in bubble growth of multicomponent mixtures.

growth of multicomponent mixtures resulting in dilution of the low boiling component in the vicinity of the surface. The critical heat fluxes of pure diphenyl and benzene were best correlated by Bernath's [1] relationship; however, none of the equations predicted the large increase of the critical heat flux for the benzene-diphenyl mixtures which was observed. Acknowledgment This work was conducted under the Atomic Energy Commission Contract AT(ll-l)-Gen-8 and is reported in more detail in NAASR-6681, "Pool Boiling of Benzene, Diphenyl, and Benzene-Diphenyl Mixtures Under Pressure," by D. A. Huber and J. C. Hoehne, which was distributed according to the category "Reactor Technology." The authors are indebted to Drs. C. V. Metzler and H. Lurie who conducted comprehensive literature surveys on the effects of additives on boiling heat transfer.

The decontamination process of solids loaded with PAH in a pilot plant is modeled. This process is separated into two main stages: fast steam stripping at the entrance of the separation tube and the subsequent slow desorption of PAH from the interior of the soil particles. The stripping process also occurs in two stages: fast diffusion controlled saturation of the partial pressures followed by the heat transfer controlled evaporation. The phase diagram of PAH/water is constructed using both the microscopic model and empirical relationships for systems with wide miscibility gaps. The numerical basis for the calculations describing desorption from the soil particles is discussed. The model for multiple PAH components is based on Langmuir type isotherms which include surface diffusion terms. The obtained results are contrasted with analytical data for systems displaying linear isotherms by dispersive approximation.