Experimental Determination of CO₂ Solubility in Liquid CH₄/N₂ Mixtures at Cryogenic Temperatures

Abstract

Coalbed methane (CBM) is an atypical natural gas that may contain a large amount of nitrogen in addition to methane. When liquefying such CH 4 /N 2 mixtures, knowledge of solid solubility is very important and, in particular, CO 2 solubility data are essential for determining the CO 2 purification index. Although experimental data for CO 2 solubility in pure methane are available for various conditions, such experimental data for CH 4 /N 2 mixtures are rare. In this paper, a solid−liquid equilibrium experimental apparatus using a static-analytic method is described. Data for CO 2 solubility in pure liquid methane were obtained and their accuracy was verified by comparison with published values. Solubility of CO 2 in CH 4 /N 2 mixtures with nitrogen molar fractions of 10, 30, 50, and 70% were then measured at cryogenic temperatures between −190 and −150 °C.

Experimental Study of the Influence of Nitrogen and Oxygen on the Solubility of Solid Carbon Dioxide in Liquid and Vapor Methane at Low Temperature

“…CO 2 solubility in liquid methane from literature data − (+), in methane + nitrogen from Shen et al (□), from Gao et al (◇), and from experimental values obtained in this work for the N 2 –CH 4 –CO 2 system (○, series 1; ●, series 2), and the N 2 –O 2 –CH 4 –CO 2 system (△, series 3; ▲, series 4).…”

“…The phase diagram of the ternary N 2 –CH 4 –CO 2 system involving a solid phase has been only partially determined through experimental data. An analysis of the experimental procedure and comparison with model results obtained at the same temperature, pressure, and global composition shows some incompleteness in the available data: declared SLE data, , they are actually SLVE data providing only the CO 2 composition in the liquid phase. Furthermore, no data for the quaternary mixture N 2 –O 2 –CH 4 –CO 2 are available, to the authors’ knowledge.…”

Measurement and Calculation of CO2 Frost Points in CH4 + CO2/CH4 + CO2 + N2/CH4 + CO2 + C2H6 Mixtures at Low Temperatures

“…The experimental setup is shown schematically in Figure . The setup used in the present work has been adopted for measuring solid–liquid equilibrium data , and gas–liquid equilibrium data successfully. Somewhat differently, the present work used it to collect gas–solid equilibrium data, that is, CO 2 frost data.…”

Experimental and Theoretical Study of CO2 Solubility in Liquid CH4/H2 Mixtures at Cryogenic Temperatures

“…The SLE experimental apparatus is shown schematically in Figure . The apparatus used in the present work has been adopted for measuring vapor–liquid equilibria (VLE), solid–vapor equilibria (SVE), and solid–liquid equilibria (SLE) , of hydrocarbon/H 2 /CO 2 systems successfully. This experiment is carried out after the equipment transformation and upgrading on the existing experimental apparatus, which consists of four parts: equilibrium system, control system, measurement system and experimental materials.…”