Simulation of Binary CO₂/CH₄ Mixture Breakthrough Profiles in MIL‐53 (Al)

Abstract

MIL-53 (Al) aluminum terephthalate, a commercial metal-organic framework, has been studied as a potential candidate for pressure swing adsorption separation of CO2/CH4binary mixtures. Pure gas isotherms of CH4and CO2measured over 0–6 MPa and at room temperature are fitted with the Dubinin-Astakhov (D-A) model. The D-A model parameters are used in the Doong-Yang Multicomponent adsorption model to predict the binary mixture isotherms. A one-dimensional multicomponent adsorption breakthrough model is then used to perform a parametric study of the effect of adsorbent particle diameter, inlet pressures, feed flow rates, and feed compositions on the breakthrough performance. Commercial MIL-53 with a particle diameter of 20 μm renders high tortuous flow; therefore it is less effective for separation. More effective separation can be achieved if MIL-53 monoliths of diameters above 200 μm are used. Faster separation is possible by increasing the feed pressure or if the starting compositions are richer in CO2. More CH4is produced per cycle at higher feed pressures, but the shortened time at higher pressures can result in the reduction of the CH4purity.

Multiscale Modeling Study of the Adsorption of CO_2 Using Different Capture Materials

“…The highest breakthrough time is recorded for run1 at 5 bar while the lowest one is observed in run 3 at 25 bar. The same behavior was mentioned by Gomez et al while applying experiments for adsorption CO2 from CO2/CH4 mixture stream by aluminum terephthalate MOF-MIL-53 (Al) 14).…”

“…Gomez et al developed a one-dimensional (1D) adsorption breakthrough model using COMSOL Multiphysics for binary mixture CO2/CH4 to validate the experimental data for capturing CO2 by Metal Organic Framework (MOF) material, MOF-MIL-53(Al). 14) They took into account the effect of total and bed porosities. They validated the proposed model by simulating the breakthrough of CO2/H2 mixture in a column of activated carbon and compared the results with the experimental data from literature by Casas et al 15) The results showed a good agreement between developed model and experimental data.…”

“…16) Although the mass balance equation applied in the suggested mathematical model is usually applied for solutes and adsorbates with low concentrations (lower than 10 vol %), the model provided good results at pressures 5, 15 and 25 bar for wide CO2 molar composition ranges, 25%, 50% and 75%. Both total and bed porosities were considered in the models proposed by Casas et al 16) and Gomez et al 14) Mansour et al model described CO2 adsorption and desorption from a stream representing flue gas (15% CO2 and 85% N2) through a fixed bed where Mg-MOF-74 was used as sorbent. 17) The four-steps process was considered: pressurization, feed, blow down and purge.…”

Statistical mechanics of binary mixture adsorption in metal–organic frameworks in the osmotic ensemble

“…Devic et al [28] and Gomez et al [40] have also reported measurement of 1 : 1 methane/carbon dioxide adsorption in MIL(53)Cr and MIL(53)Al, respectively, which will concern us here. Other relevant simulations are those of Snurr and co-workers [41].…”

“…Using the parameters for the pure single components, binary mixture isotherms of methanedioxide were calculated using both approaches, sharp transition, model A and gradual transition, model B at various carbon dioxide mole fractions (0, 0.2, 0.5, 0.8 and 1) are presented in figures 3 and 4 for 294 and 304 K, respectively. To reproduce the essential features of the mixture isotherms of Baron and co-workers [37] and also the equimolar mixture isotherm of Gomez et al [40], we have adjusted the interaction parameter J ab to 198k indicating that CH 4 and CO 2 molecules in a pore experience an effective repulsion possibly due to competition for the same binding sites. 4.…”