Flow calorimeter and measurement of the enthalpy of n-pentane

Abstract

The enthalpies of n-pentane, benzene, and water have been measured by a new flow calorimeter with results that differ from literature values by an average of 1.5 B.t.u. per pound. Results are presented for n-pentane from 100°to 700°F., with pressures up to 1400 p.s.i.a.The AMERICAN PETROLEUM INSTITUTE has initiated a program to measure the enthalpies of binary hydrocarbon mixtures experimentally at temperatures from ambient to incipient cracking, with pressures from atmospheric to 1400 p.s.i.a., for pentane and heavier hydrocarbons including paraffins, olefins, naphthenes, and aromatics. This paper describes the equipment used for the API project and presents data for w-pentane. Subsequent papers will present the results for hydrocarbon mixtures.

Enthalpies of tetralin and mixtures of tetralin and n-pentane

“…is required at the saturated liquid condition for the pure components. This difference was ascertained in the earlier study (4) to be 129.4 B.t.u. per pound for n-pentane.…”

“…36, 871 (1944). (4) Faith, W.L., Keyes, D.B., Clark, R.L., "Industrial Chemicals," 2nd ed., pp. 408-10, Wiley, New York, 1957.…”

“…The thermodynamic equation of state was used to shift all the data to the basis of 75°F. and the saturated liquid state, as described in more detail previously (4). To relate the data to the -200°F.…”

An automated flow calorimeter for heat capacity and enthalpy measurements at elevated temperatures and pressures

“…In Figure 26, the three data points determined at a pump setting of 16 ml/mln (0.17 g/s) were plotted against several different sets of literature data to illustrate the effect of pressure. Minor adjustments were made to the original data of Kharin et al, (1985) and Peng and Stiel (1974) to compensate for deviations from 323,1 K, The total enthalpy data of Lenoir et al (1970) were regressed and then differentiated at 323. four points was less than 0,4_, These data also illustrate the tremendous variation in the literature with regards to data quality, even for fluids as simple as n-pentane,…”

Enthalpies of decalins and of trans-decalin and n-pentane mixtures

“…was added to the measured values. This small enthalpy change was computed as previously described (5). It was also established that the zero pressure enthalpies for various isotherms plotted linearly against weight fraction pentane.…”