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

Abstract

In published literature, only very limited data for CO2 frost point in natural gas mixture can be found. Measurements and calculations for CH4 + CO2/CH4 + CO2 + N2/CH4 + CO2 + C2H6 mixtures over a wide range of temperature, pressure, and compositions were performed in this work. The measurements were conducted through a simple equilibrium cell by static analytic method utilizing sampling technique. The calculations were carried out by fugacity balance model based on Peng–Robinson (PR) equation of state (EoS) with van der Waals mixing rule. The calculated results agree well with the experimental results, demonstrating the reliability of PR EoS based model. By comparing data obtained from gas mixtures with different nitrogen contents and ethane contents, it is found that both nitrogen and ethane have little effect on CO2 frost point. However, the maximum pressure for CO2 frosting in CH4 + CO2 + N2 ternary mixture increases with nitrogen content; oppositely, it decreases with ethane content in CH4 + CO2 + C2H6 ternary mixture.

Application of artificial neural networks (ANN) for vapor‐liquid‐solid equilibrium prediction for CH4‐CO2 binary mixture

“…The developed ANN model was further tested using other available data with different isotherms in P‐xy vapor‐solid equilibria. Data from Xiong and Lin and Agrawal and Laverman were used. The comparison of experimental and predicted values is given in Fig.…”

“…. The experimental data of Xiong and Lin consist of five isotherms (−80, −85, −95, −105, −120°C) and the Agarwal and Laverman data consist of three isotherms (−90, −100, −120°C). The statistical analysis presented in Table was also conducted.…”

“…Xiong et al . attempted to determine the CO 2 frost‐point using both experimental and thermodynamic prediction (PR EOS).…”

Simultaneous Multiphase Flash and Stability Analysis Calculations Including Solid CO2 for CO2–CH4, CO2–CH4–N2, and CO2–CH4–N2–O2 Mixtures

“…The work by Xiong et al provides CO 2 SVE data over a wide range of composition, temperature, and pressure in the region of practical application for the natural gas industry. The method to collect phase equilibrium data was the static analytic method with sampling technique, thus providing the composition of the vapor phase at equilibrium.…”

“…As previously pointed out, since nitrogen may be present in the gaseous streams to be treated for removing CO 2 by low-temperature/cryogenic technologies, it is important to collect phase equilibrium data in the presence of solid CO 2 also for this ternary mixture. Agrawal and Laverman, Le and Trebble, and Xiong et al performed frost point measurements for this ternary system, whereas SLVE was investigated by Riva and Stringari Table summarizes the data available in the literature.…”