Validation of a New Apparatus Using the Dynamic Method for Determining the Critical Properties of Binary Gas/Gas Mixtures

Abstract

In this paper, the performance and the reliability of a new apparatus to determine the critical properties of pure components and gas/gas binary mixtures (i.e., mixtures for which the two components are gaseous at ambient conditions) with a known overall composition are studied. Critical temperatures (T c ) and critical pressures (P c ) of binary mixtures composed of carbon dioxide + a light nalkane (CO 2 + n-propane, CO 2 + n-butane) or of two light nalkanes (n-propane + n-butane) are measured. For the first time, the ability of our apparatus to determineusing the dynamic modethe critical loci of gas/gas binary systems is tested. The critical points are visually determined by observing the critical opalescence and the simultaneous disappearance and reappearance of the meniscus in the middle of the view cell which withstands operations up to 673 K and 20 MPa. The experimental critical data in this work are compared with previously measured literature data and with values predicted by the PPR78 thermodynamic model.

Experimental measurements and correlation of vapor–liquid equilibrium and critical data for the CO 2 + R1234yf and CO 2 + R1234ze(E) binary mixtures

“…3 illustrates the transition of a fluid from subcritical state to the critical state on temperature increase. The synthetic-dynamic apparatus used in this work was calibrated and validated by measuring the critical points of several pure components and of many binary mixtures (Juntarachat et al, 2012a(Juntarachat et al, , 2012b(Juntarachat et al, , 2013Jaubert et al, 2014). The experimental setup can be divided into three parts: (i) sample preparation, (ii) sample loading and (iii) critical point measurement.…”

Disposal of oil sludge with the use of liquid and supercritical fluid extraction processes with propane-butane extractant

“…Propane-butane mixture has been used as an extractant (GOST, 1993), consisting of 75 wt% propane and 25 wt% butane. According to [Juntarachat et al, 2013] the abovementioned mixture of propane-butane has the following values of critical parameters: Tcr =386 K (~113 о C); Pcr = 4.31 MPa.…”

Impregnation of Crushed Stone with Bitumenous Compounds Using Propane/Butane Impregnation Process Carried out in Supercritical Fluid Conditions

“…The authors point out that these characteristics of the phase equilibrium provide the most distinctive picture regarding the parameters of boundaries of various phase states. Figures 1-4 represent the diagrams of the phase equilibrium of the propane/butane mixture [24]- [26].…”

“…Thus the characteristics of the phase equilibrium and the character of the change of the solubility in the wide range of the change of parameters and the phase state of the propane/butane mixture determine the regime conditions of the execution of the liquid extraction (I) and the super-critical fluid impregnation (II) processes: (I): Р cr ≤ Р I < Р*, Т I < Т cr ; (II): Р II = Р I , Т II ˃ Т cr . According to [26] for the above-given composition of the propane/butane mixture intended for use the critical parameters have the following values: Т cr = 386 К (~113˚C); Р cr = 4.31 MPa. As for the value of the pressure in the first crossover point, for example, for naphthalene ( Figure 6) with carbon dioxide as the solvent it has the value of about 130 bars.…”