Integrated Material and Process Evaluation of Metal-Organic Frameworks Database for Energy-efficient SF6/N2 Separation

Abstract

<p> In this work, we proposed multi-scale screening, which employs both molecular and process-level models, to identify high-performing MOFs for energy-efficient separation of SF6 from SF<sub>6</sub> and N<sub>2</sub> mixture. Grand canonical Monte Carlo (GCMC) simulations were combined with ideal adsorption process simulation to computationally screen 14,000 metal-organic frameworks (MOFs) for adsorptive separation of SF6/N<sub>2</sub>. More than 150 high-performing MOFs were identified based on the results from GCMC simulations at the pressure and vacuum swing conditions, and subsequently evaluated using the ideal adsorption process simulation. High-performing MOFs selected for the VSA conditions are able to achieve the 90% target purity level of SF6 but none of the selected MOFs for PSA conditions could. Cascade PSA configuration was proposed and adopted to improve the purity level of the separated SF6. Cascade PSA configuration was also adopted to improve the purity. In the pump efficiency scenarios of 80, 20, and 10%, the VSA and cascade PSA cases were compared, which concluded 10% scenario prefers the PSA case whereas the VSA case is favored in the others. Top-performing MOFs identified from the multi-scale computational approach were found to be able to produce 90% purity SF<sub>6</sub> with 0.10 - 0.4 and 0.5 - 1.4 MJ per kg of SF6 for VSA and PSA, respectively.</p>

High-Throughput, Multiscale Computational Screening of Metal–Organic Frameworks for Xe/Kr Separation with Machine-Learned Parameters

“…26 For both cases, an analytical form of the equation needs to be fitted to the molecular simulation data (i.e., single component isotherm) so that the integration can be performed continuously with the coupled ODEs. The integrated approach to adsorbent material screening has been carried out for CO 2 /N 2 separation, 25 C2 separation, 38 and SF 6 / N 2 separation 35 but has not been applied to Xe/Kr separation.…”

“…Similar shortcut methods have been employed for CO 2 capture, using PSA and TSA processes, 30−34 and more recently for SF 6 separation. 35 The multiscale simulations are possible by incorporating the information obtained from the molecular simulations (e.g., adsorption isotherms) into a set of coupled algebraic ordinary differential equations. For the process simulations, the mixture gas behavior inside the column and the adsorbent materials at various pressures and gas-phase compositions is approximated by the ideal adsorbed solution theory (IAST) 36,37 or the competitive Langmuir adsorption model.…”

“…They found that the simplified model captures the most essential features of the process. Similar shortcut methods have been employed for CO 2 capture, using PSA and TSA processes, − and more recently for SF 6 separation . The multiscale simulations are possible by incorporating the information obtained from the molecular simulations (e.g., adsorption isotherms) into a set of coupled algebraic ordinary differential equations.…”

Theoretical Design of MOFs and PSA Process for Efficient Separation of CF4/NF3

“…Moreover, the advantages of flexible processing capacity, simple equipment, no byproducts, and high automation make it widely used in the field of gas separation. , In the adsorption process, the regeneration of the adsorbent can be realized by the change of temperature and pressure. Among them, the control of adsorption capacity by adjusting the temperature is called the temperature swing adsorption (TSA) process, while the pressure swing adsorption (PSA) process is a representative adsorption-based separation method where the adsorption occurs at the high pressure and desorption occurs under the low pressure . We chose PSA technology rather than the TSA process to simulate the CF 4 /NF 3 separation process in industry due to its strengths of a large range of pressure control, short time consumption, low energy demand, and low investment cost.…”

“…Nowadays, there have been over 1 000 000 MOFs and MOF-like materials, and screening the most promising material for CF 4 /NF 3 separation by experiments is less practical. Thus, high-throughput screening technology utilizing computational chemistry has become the choice for exploring MOFs with excellent adsorption separation performance that meets industrial needs. − Through high-throughput GCMC calculations, MOFs with excellent adsorption selectivity can be found quickly from the vast MOF database and the properties of MOFs can be systematically analyzed so that the method has performed a promising prospect for the gas separation application such as the separation of benzene/vinyl acetate, C 2 H 2 /CO 2 , , C 2 H 6 /CH 4 , and electronic gas Xe/Kr . MOFs have exhibited excellent adsorption performance in the field of electronic specialty gas separation.…”