Transport properties of gaseous hydrocarbons

Abstract

Measurements have been made, at temperatures between 35 and 100° C, of the viscosities and thermal conductivities of gaseous methane, ethane, ethylene, propane, propylene, cyclo -propane, n -butane, cis -2-butene, trans -2-butene, 1:3-butadiene, iso -butane, n -pentane, iso -pentane, neo -pentane, cyclo -pentane, n -hexane, neo -hexane, cyclo -hexane, benzene, n -heptane, 2:4-dimethyl-pentane, n -octane, 2:3:4-trimethyl-pentane and of carbon tetrafluoride. Viscosities were measured by observing the damping of a pendulum swinging in the vapour and by a capillary-flow viscometer. Thermal conductivities were measured by the hot-wire method. The observed values of the ratio between the transport properties are discussed in the light of the kinetic theory of gases. I t is found that highly flexible molecules show systematically lower values of the ratio, k/n , than other molecules, and it is suggested th at this is due to a special type of intermolecular collision, involving some degree of intercoiling of the two molecules. This view is relevant to the interpretation of recent work on the vibrational activation of the ethylene molecule by collision with other hydrocarbons, and on the kinetics of the thermal decomposition of gaseous hydrocarbons. Inferences can also be drawn about the ease of interchange of translational energy with vibrational and with rotational energy in collisions; these are discussed in relation to information obtained from ultrasonic dispersion measurements.

Models for viscosity, thermal conductivity, and surface tension of selected pure fluids as implemented in REFPROP v10.0

“…Lennard-Jones parameters were estimated with the method of Chung et al (Chung et al, 1988) with parameters as given in Table 1. The value of Fc in Table 2 was adjusted to provide better agreement with the data of Lambert et al (Lambert et al, 1955) and with McCoubrey and Singh (J.C. McCoubrey & Singh, 1963). Very limited liquid-phase viscosity data were available, with no data above saturation pressure.…”

“…The data of Lesche et al (Lesche, Klemp, & Nickel, 1984), Batchinski (Batschinski, 1913), and Ma et al (R. F. Ma, Shi, Duan, Han, & Liu, 2003) were used to obtain the coefficients in Table 2, and deviations from viscosity data are given in Figure 3. Based on comparisons of the gas-phase data of Lambert et al (Lambert et al, 1955) and with McCoubrey and Singh (J.C. McCoubrey & Singh, 1963), the estimated uncertainty for the gas-phase viscosity is 3 %. For the liquid phase we estimate the uncertainty is 10 % along saturation at temperatures above 120 K. At lower temperatures and at higher pressures, the uncertainty is larger.…”

“…Lennard-Jones parameters were calculated by the method of Chung et al (Chung et al, 1988); values are presented in Table 1. Liquid-phase data from Chavanne and Van Risseghem (Chavanne, 1922), Brazier and Freeman (Brazier, 1969), and Lambert et al (Lambert et al, 1955) were fit to obtain the coefficients in Table 2. Lambert et al (Lambert et al, 1955) give data in the gas phase.…”

“…Liquid-phase data from Chavanne and Van Risseghem (Chavanne, 1922), Brazier and Freeman (Brazier, 1969), and Lambert et al (Lambert et al, 1955) were fit to obtain the coefficients in Table 2. Lambert et al (Lambert et al, 1955) give data in the gas phase. Deviations with viscosity data as a function of temperature are shown in Figure 13, and as a function of pressure in Figure 14.…”

“…The estimated uncertainty in the gas phase is also 5 %. Liquid-phase thermal conductivity data of Watanabe (Watanabe, 2003) and gas-phase data of Lambert et al (Lambert et al, 1955) were fit to obtain the coefficients in Table 3. Parameters for the critical enhancement are presented in Table 4.…”