Vapor-Liquid Equilibria of Binary Systems Consisting of Nitrogen and n-Tridecane, n-Pentadecane, n-Hexadecane, and n-Heptadecane at Pressures of 1.5-9 MPa and Temperatures of 303-633 K Determined with a Raman Spectroscopy-Coupled Microfluidic Device

Vapor-liquid equilibria (VLE) of binary systemsconsistingof nitrogen and an n-alkane (n-tridecane, n-pentadecane, n-hexadecane, or n-heptadecane) were measured at a temperature range of T = 303-633 K and pressure range of p = 1.5-9 MPa. A microcapillary setup was employed, which wascoupled with an in situ Raman spectroscopy unit. Calibration was performedinside the unsaturated vapor and liquid phase regime in order to linkthe Raman signal ratios of the saturated vapor and liquid phase spectrato mole fractions. Regarding the Raman evaluation of the saturatedvapor phase spectra, a signal contribution from a liquid film canbe successfully corrected by an indirect hard modeling (IHM) approach.The obtained experimental data of the binary system n-hexadecane/nitrogen were validated with the available literaturedata, where good agreement was found. By comparing the saturated compositionsbetween the different binary systems, only small differences couldbe observed for the saturated liquid phase, while the compositionsof the saturated vapor phase clearly deviated from each other. Moreover,the experimental results of all binary systems were compared withthe calculated data obtained from different models: the predictivePeng-Robinson equation of state (PPR78) and the perturbed-chain statisticalassociating fluid theory (PC-SAFT). The data can be well describedby the models, with the absolute average deviation (AAD) that is generallyhigher for the saturated vapor phase compared with the saturated liquidphase.

Automated summary

Vapor-liquid equilibria (VLE) of binary systems consisting of nitrogen and n-alkanes have been measured using a microcapillary setup coupled with in situ Raman spectroscopy. The experimental data were compared with literature data and calculated data obtained from different models, including the predictive Peng-Robinson equation of state (PPR78) and the perturbed-chain statistical associating fluid theory (PC-SAFT). The models were able to describe the data well, with slightly higher deviations observed in the saturated vapor phase compared to the saturated liquid phase.