On the phase behaviour of the CO2 + N2O4 system at low temperatures

Abstract

• VLE data for CO 2 + NO 2 /N 2 O 4 at 253 to 303 K using a static-synthetic apparatus. • Experimental data compared to the Peng–Robinson (PR) with classic mixing rules. • Melting points of N 2 O 4 in CO 2 were measured. • Models used to predict the phase diagram of the binary system. Carbon dioxide capture transportation and storage is one of the technologies that can be employed to reduce CO 2 emissions from power plants. Unfortunately, in the post combustion capture process, CO 2 is not pure and contains impurities like SO 2 , NO x , N 2 , O 2 and Ar for example. In this paper, Vapour-Liquid-Equilibrium (VLE) of a binary system composed of CO 2 and N 2 O 4 /NO 2 have been investigated. The equipment used is based on the “static-synthetic” method with a variable cell to determine the bubble pressure or saturated pressure of the system. The setup was used to obtain bubble point data at four isotherms (253.43, 273.43, 293.43, 303.43) K and pressures up to 7.3 MPa. The accuracies of the measured temperature and pressure were estimated to be 0.03 K and 0.12 kPa, respectively. The Peng–Robinson equation of state (PR78 EoS) is used to represent the isothermal P, x data.