Title: Measurement and modelling of the solubility of dodecylcyclohexane in supercritical carbon dioxide

Authors: Xin Yang; Shuo Xiang; Peng Su; Yan He; Ping Liu; Ligong Chen

Addresses: Department of Oil, Army Logistics University of PLA, Chongqing 401311, China ' Department of Oil, Army Logistics University of PLA, Chongqing 401311, China ' Department of Oil, Army Logistics University of PLA, Chongqing 401311, China ' Department of Oil, Army Logistics University of PLA, Chongqing 401311, China ' Department of Oil, Army Logistics University of PLA, Chongqing 401311, China ' Engineering Research Centre for Waste Oil Recovery Technology and Equipment, Ministry of Education, Chongqing Technology and Business University, Chongqing 400067, China

Abstract: In developing the application of using supercritical carbon dioxide (sc-CO₂) to extract fresh base oil from waste lubricant oil, the equilibrium solubility data is very valuable. In this study, the equilibrium solubilities for one of the single lubricant oil component, dodecylcyclohexane, were determined in the temperature T = 313.2 K, 328.2 K, 343.2 K, 358.2 K, 373 K and at pressures up to 17.76 MPa. Phase equilibrium solubility measurements were made in a high-pressure visual cell with variable volume, based on the static-analytic method. Oil solubility is strongly dependent on the density of carbon dioxide (CO₂), which increased with pressure at constant temperature while decreased with temperature at same pressure. The solubility data were correlated using three density-based models: Mendez-Santiago and Teja (MST) equation, del Valle and Aguilera equation, Adachi and Lu equation, the results showed that all of these models can represent the experimental data well. Since the Adachi and Lu model provided the best regression analysis (R²) and the lowest average absolute relative deviation (AARD) than the other two models in the examined experimental range, indicating the nonlinear equation of Adachi and Lu model best agreement with the experimental data.

Keywords: supercritical carbon dioxide; waste oil; dodecylcyclohexane; equilibrium solubility; density-based model.

DOI: 10.1504/IJGW.2020.107866

International Journal of Global Warming, 2020 Vol.21 No.1, pp.35 - 49

Received: 19 Jul 2019
Accepted: 26 Oct 2019
Published online: 26 Jun 2020 *

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