A New Safety Enrichment Method for Low Concentration Coal Bed Methane-Proportion Pressure Swing Adsorption

Li, Yong Ling; Liu, Ying Shu; Yang, Xiong

doi:10.4028/www.scientific.net/amr.233-235.2276

Cited by 5 publications

(5 citation statements)

References 6 publications

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“…Thus, a new method was developed, which is safer for enrichment of LCCMM with the application of a mixture of active carbon and CMS as adsorbents and is referred to as Proportion Pressure Swing Adsorption (PPSA) [26]. Using PPSA, CH 4 and O 2 in LCCMM can be adsorbed simultaneously, with CH 4 mostly adsorbed by AC and O 2 mostly adsorbed by CMS.…”

Section: Methodsmentioning

confidence: 99%

Impact of Bed Length on Low-Concentration Coal Mine Methane Enrichment by Proportion Pressure Swing Adsorption

Liu

2013

International Journal of Coal Preparation and Utilization

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The enrichment and utilization of low-concentration coal bed methane (LCCMM) will provide a fuel source, will ensure safety from flammable gas release and will prevent significant greenhouse gas emissions. One of the special challenges in dealing with LCCMM originates from the presence of O 2 , which is difficult to process economically and explodes easily. In this work, we studied oxygen-bearing LCCMM with a CH 4 concentration of 20% and developed a safe and effective enrichment method for LCCMM: Proportion Pressure Swing Adsorption (PPSA), which used a mixture of active carbon (AC) and carbon molecular sieves (CMS) as adsorbents. With this method, CH 4 and O 2 in LCCMM can be adsorbed simultaneously because CH 4 is mostly adsorbed by active carbon and O 2 is mostly adsorbed by the CMS. Therefore, the concentration of CH 4 and O 2 is well controlled and does not exceed the explosive limit during the adsorption and desorption processes. The impact of bed length on LCCMM by PPSA was investigated. We have demonstrated the safety and feasibility of PPSA for obtaining 30% CH 4 from LCCMM, with 20% CH 4 in air as a feed stock. Our results showed that the O 2 concentration can be controlled well and does not exceed the explosive limit in both adsorption and desorption, and the CH 4 concentration in the desorption gas can be increased to more than 30% by adjusting the bed length and mass ratio of the AC and CMS.

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Section: Methodsmentioning

confidence: 99%

Impact of Bed Length on Low-Concentration Coal Mine Methane Enrichment by Proportion Pressure Swing Adsorption

Liu

2013

International Journal of Coal Preparation and Utilization

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“…Prior to metal exchange, bound and unbound solvent molecules were cleaned from structures and metal exchange and geometry optimization were performed with Materials Studio 2020. 42 Original metal (Zn) of the structures was modified using the “modify element” tool implemented in the Materials Studio, and energy of the structure was minimized with an ultrafine convergence tolerance of 10 –5 kcal/mol. A smart algorithm was employed for geometry optimization with a maximum iteration of 1000 steps.…”

Section: Computational Methodsmentioning

confidence: 99%

“…To examine the impact of metal type on the CO 2 /H 2 and CO 2 /CH 4 separation performances of SAHYIK, HIFTOG02, EFESEP, and EFESOZ, we studied eight different metals, Cd, Cu, Co, Cr, Mn, Ni, Ti, and V, which are commonly employed in both computational and experimental metal exchange studies on MOFs, ,, and obtained 32 unique M-MOFs. Prior to metal exchange, bound and unbound solvent molecules were cleaned from structures and metal exchange and geometry optimization were performed with Materials Studio 2020 . Original metal (Zn) of the structures was modified using the “modify element” tool implemented in the Materials Studio, and energy of the structure was minimized with an ultrafine convergence tolerance of 10 –5 kcal/mol.…”

Section: Computational Methodsmentioning

confidence: 99%

Metal Exchange Boosts the CO₂ Selectivity of Metal Organic Frameworks Having Zn-Oxide Nodes

2021

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A large number of metal organic frameworks (MOFs) synthesized to date have nodes with a Zn metal, and a detailed understanding of their gas separation efficiency upon metal exchange is needed to pave the way for designing the next generation of MOFs. In this work, we implemented a protocol to identify MOFs with Zn nodes out of 10,221 MOFs and classified them into two main groups. Depending on the pore properties and adsorption selectivities, two MOFs from IRMOFs and two MOFs from ZnO-MOFs were selected. The metal atom (Zn) of the selected four MOFs was exchanged with eight different metals (Cd, Co, Cr, Cu, Mn, Ni, Ti, and V), and 32 different metal-exchanged MOFs (M-MOFs) were obtained. By performing grand canonical Monte Carlo simulations, we investigated the influence of the metal type on the CO 2 /H 2 and CO 2 /CH 4 separation performances of these 32 M-MOFs. Physical properties of the MOFs such as the pore size and surface area, and chemical properties such as the partial charges of the atoms in the framework were investigated to understand the effect of metal exchange on the gas adsorption and separation performances of materials. Exchange of Zn with V and Cr led to a remarkable increase in the CO 2 uptakes of selected MOFs and these increases were reflected on the adsorption selectivity, working capacity, and the adsorbent performance score of MOFs. The exchange of Zn with V increased the selectivity of one of the MOFs from 119 to 355 and the adsorbent performance score from 70 to 444 mol/kg, while for another MOF, exchange of Zn with Cr increased the selectivity from 161 to 921 and the adsorbent performance score from 162 to 1233 mol/kg under the condition of vacuum swing adsorption. The molecular level insights we provided to explain the improvement in the gas separation performances of M-MOFs will serve as a guide to design materials with exceptional CO 2 separation performances.

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“…So the traditional approach of using a single adsorbent in the PSA process does not ensure safety in enrichment of LCCMM. Thus, a new method, referred to as Proportion Pressure Swing Adsorption (PPSA) [12] , was developed that combines the benefits from both AC and CMS adsorbents. It uses a mixture of active carbon and CMS as adsorbents so that methane and oxygen in LCCMM can be adsorbed simultaneously.…”

Section: Proportion Pressure Swing Adsorptionmentioning

confidence: 99%

Impact of Process Parameters on Oxygen-Bearing Low Concentration Coal Mine Methane Enrichment by Proportion Pressure Swing Adsorption

Liu

Yang

et al. 2012

AMR

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Conventional PSA methods with a single adsorbent can result in an explosive CH4 concentration of 5 to 15%, making low concentration coal mine methane (LCCMM) or risky in terms of safety at a concentration of 30%. Proportion Pressure Swing Adsorption (PPSA) is a new and safer enrichment method suggested for LCCMM enrichment that uses a mixture of active carbon (AC) and carbon molecular sieves (CMS) as adsorbents. The effect of adsorption Pressure, adsorption time and bed length on the PPSA process were investigated to verify the feasibility of this method. The experiment results show that the methane concentration in desorption gas and the oxygen concentration in exhaust gas increased and decreased, respectively, with an increase in adsorption pressure or bed length. And the methane concentration in desorption gas is increased with the adsorption time expanding, but the recovery of methane is reduced. So the methane concentration in desorption gas can be increased to more than 30% and the oxygen concentration in exhaust gas be decrease to less than 12% by increasing the adsorption pressure or lengthening the bed.

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A New Safety Enrichment Method for Low Concentration Coal Bed Methane-Proportion Pressure Swing Adsorption

Cited by 5 publications

References 6 publications

Impact of Bed Length on Low-Concentration Coal Mine Methane Enrichment by Proportion Pressure Swing Adsorption

Impact of Bed Length on Low-Concentration Coal Mine Methane Enrichment by Proportion Pressure Swing Adsorption

Metal Exchange Boosts the CO₂ Selectivity of Metal Organic Frameworks Having Zn-Oxide Nodes

Impact of Process Parameters on Oxygen-Bearing Low Concentration Coal Mine Methane Enrichment by Proportion Pressure Swing Adsorption

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A New Safety Enrichment Method for Low Concentration Coal Bed Methane-Proportion Pressure Swing Adsorption

Cited by 5 publications

References 6 publications

Impact of Bed Length on Low-Concentration Coal Mine Methane Enrichment by Proportion Pressure Swing Adsorption

Impact of Bed Length on Low-Concentration Coal Mine Methane Enrichment by Proportion Pressure Swing Adsorption

Metal Exchange Boosts the CO2 Selectivity of Metal Organic Frameworks Having Zn-Oxide Nodes

Impact of Process Parameters on Oxygen-Bearing Low Concentration Coal Mine Methane Enrichment by Proportion Pressure Swing Adsorption

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Metal Exchange Boosts the CO₂ Selectivity of Metal Organic Frameworks Having Zn-Oxide Nodes