Multicomponent vapor-liquid equilibria measurements for the development of an extractive distillation process for the processing of gas issuing from a carbon dioxide/EOR project

Abstract

This paper presents V-L-E data for a multicomponent C02-rich gas added to n-pentane at a series of fixed temperatures to produce an equilibrium mixture of various fixed total pressures to form a quasi-binary system containing compounds such as C02, C2H6, C3K8, H2S, n-C4H10, and n-C5H12. The experimental results provide data useable to adjust parameters and test for "proof of correlations". It suggests when the relative volatility ratios of the key components become unfavorable for LPG recovery and when the overhead vaporization tosses become excessive and the fate of small concentrations of H2S, feasible column pressures, and overhead column temperatures. It shows the importance of verifying the V-L-E behavior at near-specification concentrations when breaking an azeotrope or near-azeotropic pinch, employing the principles of extractive distillation.

Multicomponent vapor-liquid equilibria measurements for the development of an extractive distillation process for the processing of gas issuing from a CO2 enhanced oil recovery project

“…The less crucial vapor-liquid equilibria behavior representative of the bottom half of the column was not obtained in this study as it is represented by the higher temperature methane-free mixtures investigated in the previous studies (Hong and Kobayashi, 1986a).…”

“…The K values of H2S, an intermediate component, are scarcely affected by the presence of methane, at the pressures studied in this investigation. Even the n-pentane losses may be expected to be less, at the same pressure and temperature, than for the methane-free mixtures (Hong and Kobayashi, 1986a).…”

“…The effect of 14.20 mol % methane in the feed gas is clearly demonstrated in Figures 1 and 2. The presence of the methane delays criticality and hence raises the K values of the most volatile component, C02, relative to the K value of the methane-free system (Hong and Kobayashi, 1986a) and lowers the K values of the less volatile components at elevated pressures. The K values of H2S, an intermediate component, are scarcely affected by the presence of methane, at the pressures studied in this investigation.…”