A new procedure to measure high-pressure vapor-liquid equilibria Is proposed, In which both vapor-and liquid-phase samples are withdrawn without disturbing the equilibrium conditions. Vapor-liquid equilibrium data are reported for pressures approaching the critical pressures for the nitrogen-carbon dioxide system at 273.2, 293.2, and 298.2 K, and for the methane-Freon 22 (chlorodifluoromethane) system and the methane-Freon 12 (dlchtorodlfluoromethane) system both at 283.2, 273.2, and 298.2 K. Critical pressures and compositions at several temperatures were determined by means of a graphical method.

Thermal conductivltles of pure gases (Ar, N,, O,, CO,, CH,, C2H4) have been measured at temperatures from 25 to 50 OC and pressures up to 150 bar by using a vertical coaxial cylindrical cell on a relative basis. The apparatus was calibrated with Ar, O,, CH, , and C02 as standard gases. The uncertainty of the thermal conductivii obtained is estimated to be within 3%. Experimental results for pure gases were compared with the values of other investigators and the maximum deviation was 6 % . Predictive values determined by the Stiel-Thodos equation were in good agreement with the experimental results. IntroductionThe thermal conductivity of fluids is an essential basic property in the design of processing equipment involving heat transfer. Thodos (1966, 1965) measured the thermal conductivity of CH, and N2 gases and Michels

No abstract

Reid, R. C.; Prausnltz, J. M.; Sherwood, T. K. "The Properties of Gases and Stlel, L. I.; Thodos. G. AIChE J . 1964, 10, 26-29. Tanaka, Y.; Noguchi, M.; Kubota, H.; Makita, T. J . Chem. fng. Jpn. 1979, Touloukian, Y. S.; Liley, P. E.; Saxena, S. C. "Thermal Conductivity, Non-149-160. MISIC, D.; tho do^, G. AIChf J . 1965. 11, 650-656. MISIC, D.; Thodos, G. t ' h y~i~a 1966, 32, 885-899. Liquids", 3rd ed.; McGraw-Hill: New York, 1977; pp 629-665. 12, 171-176. metallic Liquids and Gases, Thermophysicai Properties of Matter"; IFI, Plenum Press: New York, 1970; Voi. 3. Tsederberg, N. V. "Thermal Conductivity of Gases and Liquids"; The MIT Press: Cambridge, MA 1963. Tufeu, R.; Le Neindre, 8.; Bury, P. fhysica, 1969, 4 4 , 81-85. The thermal conductivities of blnary gases (N2-02, N,-Ar, C0,-Ar, C0,-CH,) have been measured at temperatures from 25 to 35 OC and under pressures up to 90 bar. The measurements were carried out with a vertical coaxial cylindrical cell. The uncertainty of the data is estimated to be within 3 % . The experimental results were compared with the values calculated by the Wassiljewa equation, in which the Mason-Saxena equation was used as a combination factor, and with values predicted by the Stlel-Thodos equation extended to binary gas mixtures. Both methods were found to represent the experimental results within a maximum deviation of 5 % . The uniformity of flow rates among the parallel tubes of a piping manifold is governed by the variations in fluid pressure inside the entrance and discharge headers. These result from fluid friction and from loss or gain of fluid momentum at exit and entrance ports. Using hydraulic flow coefficients derived from experiments, a theory for the distribution of velocities is developed for turbulent flow In manifolds having cylindrical headers of equal diameter. The results are confirmed by experiment and are used in two design examples.

No abstract