Phase equilibriums for aqueous solutions of ammonia and carbon dioxide

Abstract

A static experimental apparatus has been used to measure vapor-liquid equilibria for aqueous systems containing ammonia and carbon dioxide. Both phases were sampled and analyzed using gas-liquid chromatography. For aqueous mixtures of ammonia-potassium nitrate and ammonia-potassium sulfate, measurements were made at 100 and 150 °C to examine the effects of salts at elevated temperatures. Some data are also given for the NH3/C02/H20 system at 100 and 150 °C. These and other recent experimental data were used to update the computerized molecular-thermodynamic correlation of Edwards et al. for sour-water phase equilibria, as required for water-pollution abatement.

Vapor-liquid equilibrium data for the ammonia-water system and its description with a modified cubic equation of state

“…Gillespie et al ( 7 ) also required large negative cross-virial coefficients in order for their activity coefficient based model to correlate both pressure and vapor-phase behavior. That a single kr does not accurately describe both the pressure and vapor-phase compositions suggests that the separation of the vapor and liquid phases as expressed by eq 4 is not right.…”

“…Some authors had attributed these discrepancies to thermodynamically inconsistent data (Edwards et al (74), for example), others to shortcomings in existing models (Peng and Robinson (72) and Heidemann and Rizvi (77), for example). Gillespie et al ( 7 ) were able to resolve this disagreement. They first took an extenstve data set that included both total pressure and T-Px-y data and then fit these data with an activity coefficient To whom CaTeepondence should be addressed at the University of Toledo.…”

“…The third objective was to see if the improved accuracy of our T-P-x data and the improved equatbn of state methods could successfuily remove discrepancies in the vapor-phase compositions, as Gillespie et el. ( 7) had done with their T-P-x-y data and activity coefficient model.…”

The applicability of activities in kinetic expressions: A more fundamental approach to represent the kinetics of the system CO2–OHHaubrock1, Hogendoorn2, Versteeg3 2007Chemical Engineering Science420250View full textAdd to dashboardCite

“…Interactions between carbon dioxide and dissolved bicarbonate or carbonate have been omitted as those interactions are reported to be negligible (Edwards et al, 1978;Pawlikowski et al, 1982). Due to the low concentration of H 3 O + ions in the caustic solutions, all interaction parameters between this component and CO 2 have been set to zero.…”

Rapid on-line sampler-injector: a reliable tool for HT-HP sampling and on-line GC analysis

“…It is important to take a special care to ensure the liquid samples do not undergo any vaporisation and to avoid any condensation of the heavy fractions inside the transfer line. Pawlikowski et al [3] also used the technique of expanding the samples on-line with the same inconveniences. A valve with a sampling loop was used to send a small quantity of the sample into a gas chromatograph.…”