Component Fugacities in Hydrogen-Ammonia-Propane Mixtures. I. The Fugacity of Hydrogen

Abstract

The fugacity of hydrogen in mixtures with ammonia and propane was determined directly from a physical equilibrium method using a palladium-silver semipermeable membrane, at temperatures between 71 and 121°C (160 and 250°F) and pressures up to 102 atm (1500 psi). Measurements at low hydrogen concentrations were emphasized in order to investigate the region of higher nonideality of the gas mixtures. The data obtained were used to evaluate the predictive properties of a number of equations of state. These included both the original and a modified Redlich-Kwong, Black, Martin-Hou, Benedict-Webb-Rubin, and the virial equations.

An apparatus for direct fugacity measurements on mixtures containing hydrogen

“…The error bars representthe uncertainty of a typical 44H'-x, 2 pair, and will be discussed in more detail later. The data represented by the triangles on figure 6 are the results of an earlier study [17]. Although the earlier data were taken at a slightly different temperature (345 K instead of the 353 K in the present work), the agreement is striking.…”

“…Such identification does not imply recommendation or endorsement by the National Bureau of Standards, nor does it imply that the materials or equipment identified are necessarily the best available for the purpose. '35 o -this work A -previous data of Antezana (17], taken at 345 K. 23% in the hydrogen-propane mixture at 353 K. This is expected because of the higher reduced temperature of methane. The value of OH', changes most sharply in the region of low hydrogen mole fraction, as expected [10].…”

“…It is more convenient to deal with a dimensionless quantity called the fugacity coefficient, Oj, defined by (2) where Pi is the partial pressure of component i [6]. The fugacity coefficient of this single component can be determined using the virial equation (truncated after the third virial coefficient) [17,18],…”

The vapor‐liquid equilibrium of the hydrogen—n‐butane system at elevated pressures

“…In addition, the fugacity of hydrogen was determined by measuring the temperature and ressure of the pure hydrogen on one side of its p-V-T behavior. The principle of the semipermeable membrane technique and its applications in fugacity measurements have been described in detail by Cheh (1973) and by Antezana and Cheh ( 1975).…”

“…The same apparatus (including the palladium-silver semipermeable membrane) and analytical equipment used to determine the fugacity of hydrogen in mixtures with ammonia and propane (Antezana and Cheh, 1975) were used for the present investigation. Only a number of relatively minor modifications were made.…”