Key words: sulfur, supercritical propane/butane mixture, phase equilibrium, solubility, thermodynamic model, Рeng-Robinson equation
The results of an experimental study of the phase equilibrium of the sulfur-propane/butane system carried out in the temperature range 403-443 K and pressure range 5.3-24.5 MРa using a high-pressure optical cell are presented. The V type of phase behavior is established. The solubility of sulfur in a supercritical propane-butane mixture under the above mentioned thermodynamic conditions is estimated based on the characteristics of the vapor branch of the phase equilibrium of the sulfur-propane/butane system and described using the Рeng-Robinson equation of state in combination with the rule of combining Mukhopadhyay and Rao. It has been established that the propane-butane mixture in the SCF state, along with good extraction properties, allows for the desulfurization of commercial hydrocarbons. Reducing the pressure from 25 to 7 MРa makes it possible to reduce the sulfur content at the 413 K isotherm by two times, at the 443 K isotherm by 10 times.
doi: 10.34984/SCFTP.2022.17.4.004