Vapor-Liquid equilibria of the systems 1-octanol/nitrogen and 1-octanol/oxygen at pressures from 3 to 9 MPa and temperatures up to 613 K – Measured in a microcapillary with Raman spectroscopy

• Published in: Fuel (Guildford) Vol. 323; p. 124352
• Main Authors: Fechter, Michael H.H., Koschack, Jessica, Braeuer, Andreas S.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.09.2022; Elsevier BV
• Subjects: 1-Octanol; Binary systems; Calibration; Composition; Data points; Equations of state; High temperature and pressure; Liquid phases; Liquid-vapor equilibrium; Microfluidics; Nitrogen; Octanol; Oxygen; Raman; Raman spectroscopy; Spectroscopic analysis; Spectroscopy; Spectrum analysis; Taylor flow; Vapor phases; Vapors; Vapor–liquid equilibria (VLE); High temperature and pressure; Vapor–liquid equilibria (VLE); Raman; Equations of state; Microfluidics
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/j.fuel.2022.124352

[Display omitted] •Acquisition of new vapor–liquid equilibrium (VLE) data at elevated temperature and pressure conditions for the binary system 1-octanol/nitrogen and 1-octanol/oxygen, which are scarce / not available in the archival literature.•Use of an in situ Raman Spectroscopy unit.•Applying a precise calibration and spectral evaluation procedure.•Modelling using the Peng-Robinson equation of state (PR-EOS) as well as the perturbed-chain statistical associating fluid theory (PC-SAFT) Vapor-liquid equilibria (VLE) of the binary systems 1-octanol/nitrogen and 1-octanol/oxygen were investigated at engine-relevant temperatures (T=303to613K for 1-octanol/nitrogen; T=303to493K for 1-octanol/oxygen) and pressures (p=3to9MPa). In order to acquire vapor–liquid equilibrium data, the pressurized fuel (1-octanol) and gas (nitrogen or oxygen) are mixed in a T-junction, where a Taylor flow of alternating liquid-phase and vapor-phase segments is formed. This segmented flow passes into a microcapillary that is inserted in a steal heating block, in which the equilibrium compositions of both phases are measured by in situ Raman spectroscopy. The measured Raman signal ratios are correlated to mole fractions by a calibration, performed in the unsaturated vapor and liquid phase regimes. The obtained VLE data agree well with the few available literature data points. The VLE compositions calculated by the Peng-Robinson equation of state (PR-EoS) and perturbed-chain statistical associating fluid theory (PC-SAFT) were furthermore compared to the here obtained experimental data. Both models show good agreement as indicated by the absolute average deviations (AAD), that are at maximum 9.5 % for the saturated vapor phase and 4.2 % for the saturated liquid phase.