Phase equilibria analysis of the binary N2-NH3 and H2-NH3 systems and prediction of ternary phase equilibria

Presentation, Validation and Application of the EnergyProcess Library

“…Mixture models are the most complex of all and involve several models. They are either based on SRK/PSRK models or in-house models (mixture NH3 / H2 / N2 or Moist gas) based on Henry and Raoult's laws coupled with correlations for the Vapour Liquid Equilibrium (VLE) calculation (Alesandrini et al, 1972;Reamer andSage, 1959a, 1959b;Sawant et al, 2006). The media composing the package are represented in Figure 2.…”

Simulation of the Mono-Thermal Ammonia Hydrogen Chemical Exchange Tower as a Reactive Absorption System

“…A recently developed phase equilibria model for the ternary system N 2 -H 2 -NH 3 is used in the present work. 9 For the bulk mass and energy balances over a tray, a system of three components yields a total of eight equations (namely, three mass balances, eq 8; three phase equilibria relations, eq 9; overall energy balance, eq 10; and equation for pressure drop, eq 7) against a total of 18 variables (12 molar flows, 3 temperatures, and 3 pressures of three stages involved in the balance equations) required to fully characterize a tray. A typical set of operating data consists of temperature, pressure, catalyst concentration, D/(D + H), and flows at the entry and exit points of both the exchange towers, T1 and T2.…”

“…Because ammonia exhibits self-association in the vapor phase, especially at low temperatures and high pressures, the phase equilibrium relation for ammonia must include the association phenomena and its consequent effect on the vapor phase fugacity of ammonia. A recently developed phase equilibria model for the ternary system N 2 −H 2 −NH 3 is used in the present work …”

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2 Fitted curve and experimental points for the rate constant of the chemical exchange reaction. (▪) Experimental data (ref ), (solid line) fitted curve for 36 kg KNH 2 /m 3 , (dashed line) fitted curve for 18 kg KNH 2 /m 3 , (dotted-dashed line) fitted curve for 9 kg KNH 2 / m 3 , (□) predicted point at 4.5 kg KNH 2 /m 3 .

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