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

Abstract

Methane-rich industrial byproducts, such as coke oven gas (COG) and synthetic ammonia exhaust tail gas, are often regarded as promising sources of unconventional natural gas. The design spec for liquefaction of these kinds of unconventional natural gas is quite different from that of conventional natural gas due to the presence of some special substances, such as hydrogen. In this work, CO2 solubility in liquid CH4/H2 mixtures is measured utilizing a static solid–liquid equilibrium (SLE) experimental apparatus. The experiments are carried out at cryogenic temperatures between 90 and 150 K in the pressure range of about 1.7–5.4 MPa. The results are compared with calculations based on the GERG-2008 and Peng–Robinson (PR) equations of state. It is found that, compared with the solubility of CO2 in pure methane, the existence of hydrogen makes CO2 solubility increase significantly between −160 and −145 °C and decrease significantly at temperatures above −140 °C. The results provide the basis for the CO2 purification system of the coke oven gas and synthetic natural gas liquefaction plant.

Measurement and Theoretical Calculation of CO2 Solubility Data in Liquid CH4 + C2H6 Mixtures at Cryogenic Temperatures

“… a Expanded uncertainties: U T = 0.28 K; U x, r (CH 4 ) = 0.0407, U x, r (CO 2 ) = 0.0407 b x : The calculation result obtained according to the correlation formula fitted by this experimental data. ( x = −1.68105 + 0.03484 T – 2.42185 × 10 –4 T 2 + 5.66534 × 10 –7 T 3 ); x 1 : Experimental data from Davis et al; x 2 : Experimental data from Shen et al; x 3 : Experimental data from Xu et al; Δ 1 = ( x – x 1 )/ x 1 ; Δ 2 = ( x – x 2 )/ x 2 ; Δ 3 = ( x – x 3 )/ x 3 ; MRD = |( x – x 1 )/ x 1 |/ n or MRD = |( x – x 2 )/ x 2 |/ n or MRD = |( x – x 3 )/ x 3 |/ n. …”

“…The experimental data of CO 2 solubility in pure methane liquid are available in several literature studies, and the reliability of the experimental method and this experimental setup has been verified in our previous publication. 13 The testing temperature range in this study has been covered by previous research although does not coincide with the previous testing temperature. Therefore, we can also make a comparison between this study and the literature data.…”

“…The author found that the root-mean standard deviation of this model is 1.0−2.9 K, which is much lower than that of the Kohn and Luks Solids Solubility Program (KLSSP) model (8.0−20.7 K). Xu et al 13 found that the calculation results of CO 2 solubility based on the GERG-2008 EoS are more accurate than that based on PR EoS for natural gas containing hydrogen.…”

The Prospects of Clay Minerals from the Baltic States for Industrial-Scale Carbon Capture: A Review

“…Among these, the cryogenic distillation is amidst the most common conventional approaches. In turn, most unconventional methods involve various cryogenic fluids, heat exchangers, and cryogenic packed beds to fix CO 2 [41,[59][60][61].…”