Grand Canonical Monte Carlo (GCMC) simulations have been performed to study the localization and adsorption behavior of benzene and propylene, in purely siliceous MWW zeolite (ITQ-1). By analyzing the locations of ben...Grand Canonical Monte Carlo (GCMC) simulations have been performed to study the localization and adsorption behavior of benzene and propylene, in purely siliceous MWW zeolite (ITQ-1). By analyzing the locations of benzene and propylene in ITQ-1, it can be deduced that the alkylation of benzene and propylene will mainly happen in 12-MR supercages at the external surface or close to the external surface. The adsorption isotherms of benzene and propylene at 315K and 0 similar to 3.5kPa are predicted, and the results for benzene generally coincide with the trend from the experiments of a series of aromatic compounds.展开更多
Grand canonical Monte Carlo simulation(GCMCs)is utilized for studying hydrogen storage gravimetric density by pha-graphene at different metal densities,temperatures and pressures.It is demonstrated that the optimum ad...Grand canonical Monte Carlo simulation(GCMCs)is utilized for studying hydrogen storage gravimetric density by pha-graphene at different metal densities,temperatures and pressures.It is demonstrated that the optimum adsorbent location for Li atoms is the center of the seven-membered ring of pha-graphene.The binding energy of Li-decorated phagraphene is larger than the cohesive energy of Li atoms,implying that Li can be distributed on the surface of pha-graphene without forming metal clusters.We fitted the force field parameters of Li and C atoms at different positions and performed GCMCs to study the absorption capacity of H_(2).The capacity of hydrogen storage was studied by the differing density of Li decoration.The maximum hydrogen storage capacity of 4Li-decorated pha-graphene was 15.88 wt%at 77 K and100 bar.The enthalpy values of adsorption at the three densities are in the ideal range of 15 kJ·mol^(-1)-25 kJ·mol^(-1).The GCMC results at different pressures and temperatures show that with the increase in Li decorative density,the hydrogen storage gravimetric ratio of pha-graphene decreases but can reach the 2025 US Department of Energy's standard(5.5 wt%).Therefore,pha-graphene is considered to be a potential hydrogen storage material.展开更多
目前,由于化石燃料的广泛使用致使大量二氧化碳被排放进入大气,由此导致的温室效应将引发严重的生态灾难。碳捕获与封存(Carbon capture and sequestration,CCS)技术是解决这一困境的有效手段。其中碳捕获技术主要适用于燃煤电厂,包括...目前,由于化石燃料的广泛使用致使大量二氧化碳被排放进入大气,由此导致的温室效应将引发严重的生态灾难。碳捕获与封存(Carbon capture and sequestration,CCS)技术是解决这一困境的有效手段。其中碳捕获技术主要适用于燃煤电厂,包括燃烧后捕获,燃烧前捕获和富氧燃烧捕获3种策略。立足于理论研究,首先根据燃煤电厂应用多孔材料进行碳捕获的流程建立物理模型,并讨论了评估材料碳捕获性能的热力学参数。接下来讨论了理论模拟碳捕获问题的方法,包括巨正则蒙特卡罗模拟与第一性原理计算,并提出了一种兼具第一性原理计算准确性与蒙特卡罗模拟高效性优势的多尺度模拟计算方法,该方法可以准确、高效地预测材料的碳捕获性能。展开更多
This article presents a multiscale simulation approach starting at the molecular level for the adsorption process development. A grand canonical Monte Carlo method is used for the prediction of adsorption isotherms of...This article presents a multiscale simulation approach starting at the molecular level for the adsorption process development. A grand canonical Monte Carlo method is used for the prediction of adsorption isotherms of methanol on an activated carbon at the molecular level. The adsorption isotherms obtained in the linear region （or adsorption constant） are exploited as a model parameter required for the adsorption process simulation. The adsorption process model described by a set of partial differential equations （PDEs） is solved by using the conservation element and solution element method, which produces a fast and an accurate numerical solution to PDEs. The simulation results obtained from the adsorption constant estimated at the molecular level are in good agreement with the experimental results of the pulse response. The systematical multiscale simulation approach addressed in this study may be useful to accelerate the adsorption process development by reducing the number of experiments.展开更多
Among the different types of CO_(2)capture technologies for post-combustion,sorption CO_(2)capture technology with carbon-based sorbents have been extensively explored with the purpose of enhancing their sorption perf...Among the different types of CO_(2)capture technologies for post-combustion,sorption CO_(2)capture technology with carbon-based sorbents have been extensively explored with the purpose of enhancing their sorption perfor-mance by doping hetero elements due to the rapid reaction kinetics and low costs.Herein,sorption capacity and selectivity for CO_(2)and N 2 on carbon-based sorbents doped with elements such as nitrogen,sulfur,phosphorus,and boron,are evaluated and compared using the grand canonical Monte Carlo(GCMC)method,the universal force field(UFF),and transferable potentials for phase equilibria(TraPPE).The sorption capacities of N-doped porous carbons(PCs)at 50℃were 76.1%,70.7%,50.6%,and 35.7%higher than those of pure PCs,S-doped PCs,P-doped PCs,and B-doped PCs,respectively.Its sorption selectivity at 50℃was approximately 14.0,nearly twice that of pure PCs or other hetero-element-doped PCs.The N-doped PCs showed the largest sorption heat at 50℃among all the PCs,approximately 20.6 kJ·mol^(−1),which was 9.7%−25.5%higher than that of the pure PCs under post-combustion conditions.Additionally,with the product purity of 41.7 vol.%−75.9 vol.%for vacuum pressure swing sorption,and 53.4 vol.%−83.6 vol.%for temperature swing sorption,the latter is more suitable for post-combustion conditions than pressure-swing sorption.展开更多
文摘Grand Canonical Monte Carlo (GCMC) simulations have been performed to study the localization and adsorption behavior of benzene and propylene, in purely siliceous MWW zeolite (ITQ-1). By analyzing the locations of benzene and propylene in ITQ-1, it can be deduced that the alkylation of benzene and propylene will mainly happen in 12-MR supercages at the external surface or close to the external surface. The adsorption isotherms of benzene and propylene at 315K and 0 similar to 3.5kPa are predicted, and the results for benzene generally coincide with the trend from the experiments of a series of aromatic compounds.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11904175,11804169,and 11804165)the Graduate Innovation Project of Jiangsu Province,China(Grant No.KYCX210700)。
文摘Grand canonical Monte Carlo simulation(GCMCs)is utilized for studying hydrogen storage gravimetric density by pha-graphene at different metal densities,temperatures and pressures.It is demonstrated that the optimum adsorbent location for Li atoms is the center of the seven-membered ring of pha-graphene.The binding energy of Li-decorated phagraphene is larger than the cohesive energy of Li atoms,implying that Li can be distributed on the surface of pha-graphene without forming metal clusters.We fitted the force field parameters of Li and C atoms at different positions and performed GCMCs to study the absorption capacity of H_(2).The capacity of hydrogen storage was studied by the differing density of Li decoration.The maximum hydrogen storage capacity of 4Li-decorated pha-graphene was 15.88 wt%at 77 K and100 bar.The enthalpy values of adsorption at the three densities are in the ideal range of 15 kJ·mol^(-1)-25 kJ·mol^(-1).The GCMC results at different pressures and temperatures show that with the increase in Li decorative density,the hydrogen storage gravimetric ratio of pha-graphene decreases but can reach the 2025 US Department of Energy's standard(5.5 wt%).Therefore,pha-graphene is considered to be a potential hydrogen storage material.
文摘目前,由于化石燃料的广泛使用致使大量二氧化碳被排放进入大气,由此导致的温室效应将引发严重的生态灾难。碳捕获与封存(Carbon capture and sequestration,CCS)技术是解决这一困境的有效手段。其中碳捕获技术主要适用于燃煤电厂,包括燃烧后捕获,燃烧前捕获和富氧燃烧捕获3种策略。立足于理论研究,首先根据燃煤电厂应用多孔材料进行碳捕获的流程建立物理模型,并讨论了评估材料碳捕获性能的热力学参数。接下来讨论了理论模拟碳捕获问题的方法,包括巨正则蒙特卡罗模拟与第一性原理计算,并提出了一种兼具第一性原理计算准确性与蒙特卡罗模拟高效性优势的多尺度模拟计算方法,该方法可以准确、高效地预测材料的碳捕获性能。
基金the Basic Research Program of the Korea Science & Engineering Foundation (KoSEF, No. R01-2006-000-10786-0).
文摘This article presents a multiscale simulation approach starting at the molecular level for the adsorption process development. A grand canonical Monte Carlo method is used for the prediction of adsorption isotherms of methanol on an activated carbon at the molecular level. The adsorption isotherms obtained in the linear region （or adsorption constant） are exploited as a model parameter required for the adsorption process simulation. The adsorption process model described by a set of partial differential equations （PDEs） is solved by using the conservation element and solution element method, which produces a fast and an accurate numerical solution to PDEs. The simulation results obtained from the adsorption constant estimated at the molecular level are in good agreement with the experimental results of the pulse response. The systematical multiscale simulation approach addressed in this study may be useful to accelerate the adsorption process development by reducing the number of experiments.
基金the National Natural Science Foundation of China for Distinguished Young Scholars(Grant No.:51825602)。
文摘Among the different types of CO_(2)capture technologies for post-combustion,sorption CO_(2)capture technology with carbon-based sorbents have been extensively explored with the purpose of enhancing their sorption perfor-mance by doping hetero elements due to the rapid reaction kinetics and low costs.Herein,sorption capacity and selectivity for CO_(2)and N 2 on carbon-based sorbents doped with elements such as nitrogen,sulfur,phosphorus,and boron,are evaluated and compared using the grand canonical Monte Carlo(GCMC)method,the universal force field(UFF),and transferable potentials for phase equilibria(TraPPE).The sorption capacities of N-doped porous carbons(PCs)at 50℃were 76.1%,70.7%,50.6%,and 35.7%higher than those of pure PCs,S-doped PCs,P-doped PCs,and B-doped PCs,respectively.Its sorption selectivity at 50℃was approximately 14.0,nearly twice that of pure PCs or other hetero-element-doped PCs.The N-doped PCs showed the largest sorption heat at 50℃among all the PCs,approximately 20.6 kJ·mol^(−1),which was 9.7%−25.5%higher than that of the pure PCs under post-combustion conditions.Additionally,with the product purity of 41.7 vol.%−75.9 vol.%for vacuum pressure swing sorption,and 53.4 vol.%−83.6 vol.%for temperature swing sorption,the latter is more suitable for post-combustion conditions than pressure-swing sorption.
