scholarly journals Evaluating Methane Adsorption Characteristics of Coal-Like Materials

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 751
Author(s):  
Pengxiang Zhao ◽  
Hui Liu ◽  
Chun-Hsing Ho ◽  
Shugang Li ◽  
Yanqun Liu ◽  
...  
Keyword(s):  
Silica Gel ◽  
Molecular Sieves ◽  
Molecular Sieve ◽  
Physical Simulation ◽  
Methane Adsorption ◽  
Adsorption Coefficient ◽  
Activated Alumina ◽  
Adsorption Model ◽  
Adsorption Characteristics ◽  
As Adsorption

In order to investigate the methane adsorption characteristics of coal seam materials in a “solid–gas” coupling physical simulation experiment, activated alumina, silica gel, the 3Å molecular sieve, 4Å molecular sieve and 5Å molecular sieve were selected as adsorption materials. According to the pore structure and adsorption characteristics, coal samples at the Aiweiergou #1890 working face were prepared as compared materials. The WY-98A methane adsorption coefficient measuring instrument was used to carry out this adsorption experiment under different temperatures, particle sizes and moisture contents. The results suggested that the adsorption principles of three kinds of molecular sieves under multiple factors do not fully fit a Langmuir adsorption model, and cannot be used as adsorption materials. The changing trend of the adsorption increment of activated alumina and silica gel are similar to that of coal samples, so they can be used as a coal-like materials. The methane adsorption coefficient a value changing trends of activated alumina and silica gel appear to be the same as the Aiweiergou #1890 coal samples, but the results from silica gel are closer to that of coal samples. Thus, silica gel is preferred as the adsorption material. The result provides an experimental basis for the selection of methane-adsorbing materials and carrying out “solid–gas” coupling physical simulation experiments in a physically similar testing model.

Desiccant Degradation in Desiccant Cooling Systems: An Experimental Study

1993 ◽  
Vol 115 (4) ◽  
pp. 212-219 ◽  
Author(s):  
A. A. Pesaran
Keyword(s):  
Thermal Cycling ◽  
Silica Gel ◽  
Molecular Sieves ◽  
Cooling System ◽  
Ambient Air ◽  
Activated Alumina ◽  
Humid Air ◽  
Cooling Systems ◽  
Degradation Data ◽  
Capacity Loss

We conducted experiments to quantify the effects of thermal cycling and exposure to contamination on solid desiccant materials that may be used in desiccant cooling systems. The source of contamination was cigarette smoke, which is considered one of the worst pollutants in building cooling applications. We exposed five different solid desiccants to “ambient” and “contaminated” humid air: silica gel, activated alumina, activated carbon, molecular sieves, and lithium chloride. We obtained the moisture capacity of samples as a function of exposure time. Compared to virgin desiccant samples, the capacity loss caused by thermal cycling with humid ambient air was 10 percent to 30 percent for all desiccants. The capacity loss because of combined effect of thermal cycling with “smoke-filled” humid air was between 30 percent to 70 percent. The higher losses occurred after four months of experiment time, which is equivalent to four to eight years of field operation. Using a system model and smoke degradation data on silica gel, we predicted that, for low-temperature regeneration, the loss in performance of a ventilation-cycle desiccant cooling system would be between 10 percent to 35 percent, in about eight years, with higher value under worst conditions.

Methane Adsorption Characteristics and Adsorption Model Applicability of Tectonically Deformed Coals in the Huaibei Coalfield

2018 ◽  
Vol 32 (7) ◽  
pp. 7485-7496 ◽  
Author(s):  
Guanwen Lu ◽  
Chongtao Wei ◽  
Jilin Wang ◽  
Gaoyuan Yan ◽  
Junjian Zhang ◽  
...  
Keyword(s):  
Methane Adsorption ◽  
Adsorption Model ◽  
Adsorption Characteristics ◽  
Huaibei Coalfield ◽  
Tectonically Deformed Coals

scholarly journals Enantiomerically enriched, polycrystalline molecular sieves

2017 ◽  
Vol 114 (20) ◽  
pp. 5101-5106 ◽  
Author(s):  
Stephen K. Brand ◽  
Joel E. Schmidt ◽  
Michael W. Deem ◽  
Frits Daeyaert ◽  
Yanhang Ma ◽  
...  
Keyword(s):  
Molecular Sieves ◽  
Molecular Sieve ◽  
Ring Opening ◽  
Heterogeneous Catalysts ◽  
Computational Results ◽  
Organic Structure ◽  
Transmission Electron ◽  
Ring Opening Reaction ◽  
Enantioselective Adsorption ◽  
As Adsorption

Zeolite and zeolite-like molecular sieves are being used in a large number of applications such as adsorption and catalysis. Achievement of the long-standing goal of creating a chiral, polycrystalline molecular sieve with bulk enantioenrichment would enable these materials to perform enantioselective functions. Here, we report the synthesis of enantiomerically enriched samples of a molecular sieve. Enantiopure organic structure directing agents are designed with the assistance of computational methods and used to synthesize enantioenriched, polycrystalline molecular sieve samples of either enantiomer. Computational results correctly predicted which enantiomer is obtained, and enantiomeric enrichment is proven by high-resolution transmission electron microscopy. The enantioenriched and racemic samples of the molecular sieves are tested as adsorbents and heterogeneous catalysts. The enantioenriched molecular sieves show enantioselectivity for the ring opening reaction of epoxides and enantioselective adsorption of 2-butanol (the R enantiomer of the molecular sieve shows opposite and approximately equal enantioselectivity compared with the S enantiomer of the molecular sieve, whereas the racemic sample of the molecular sieve shows no enantioselectivity).

scholarly journals Simulation of methane adsorption in diverse organic pores in shale reservoirs with multi-period geological evolution

2021 ◽  
Author(s):  
Shangbin Chen ◽  
Chu Zhang ◽  
Xueyuan Li ◽  
Yingkun Zhang ◽  
Xiaoqi Wang
Keyword(s):  
Organic Matter ◽  
Pore Size ◽  
Adsorption Capacity ◽  
Thermal Evolution ◽  
Methane Adsorption ◽  
Storage Site ◽  
Pressure Sensitivity ◽  
Adsorption Characteristics ◽  
Shale Reservoirs ◽  
Organic Pores

AbstractIn shale reservoirs, the organic pores with various structures formed during the thermal evolution of organic matter are the main storage site for adsorbed methane. However, in the process of thermal evolution, the adsorption characteristics of methane in multi type and multi-scale organic matter pores have not been sufficiently studied. In this study, the molecular simulation method was used to study the adsorption characteristics of methane based on the geological conditions of Longmaxi Formation shale reservoir in Sichuan Basin, China. The results show that the characteristics of pore structure will affect the methane adsorption characteristics. The adsorption capacity of slit-pores for methane is much higher than that of cylindrical pores. The groove space inside the pore will change the density distribution of methane molecules in the pore, greatly improve the adsorption capacity of the pore, and increase the pressure sensitivity of the adsorption process. Although the variation of methane adsorption characteristics of different shapes is not consistent with pore size, all pores have the strongest methane adsorption capacity when the pore size is about 2 nm. In addition, the changes of temperature and pressure during the thermal evolution are also important factors to control the methane adsorption characteristics. The pore adsorption capacity first increases and then decreases with the increase of pressure, and increases with the increase of temperature. In the early stage of thermal evolution, pore adsorption capacity is strong and pressure sensitivity is weak; while in the late stage, it is on the contrary.

Preparation and Characterization of Ni-Containing Aluminophosphate Molecular Sieves

2011 ◽  
Vol 418-420 ◽  
pp. 617-620
Author(s):  
Ying Sun ◽  
Lan Ying Ge
Keyword(s):  
Oxidation State ◽  
Molecular Sieves ◽  
Molecular Sieve ◽  
Crystalline Form ◽  
Spectroscopic Techniques ◽  
Tetrahedral Coordination ◽  
Tetrahedral Geometry ◽  
Nickel Ions ◽  
Aluminophosphate Molecular Sieves

Aluminophosphate molecular sieve and Ni(II)-containing APO-5 materials were synthesized hydrothermally and characterized by various analytical and spectroscopic techniques. It indicates that the nickel ions with a divalent oxidation state can incorporate into the tetrahedral coordination in mesoporous aluminophosphate very well. The better crystallizing temperature is explored. A stronger crystalline form is obtained with the addition of HF. Further, microporous aluminophosphate molecular sieves and Ni(II) ions remain in a tetrahedral geometry even after calcination at 550 °C.

Progress in Synthesis of Micro- and Mesoporous Composite Molecular Sieve

2011 ◽  
Vol 396-398 ◽  
pp. 1151-1156
Author(s):  
Wen Yuan Wu ◽  
Chun Wei Shi ◽  
Xue Bian
Keyword(s):  
Hydrothermal Synthesis ◽  
Microwave Radiation ◽  
Vapor Phase ◽  
Molecular Sieves ◽  
Molecular Sieve ◽  
Vapor Phase Transport ◽  
Mesoporous Composite ◽  
Composite Molecular Sieve ◽  
Potential Applications ◽  
Phase Transport

Micro- and mesoporous composite molecular sieves enable to achieve grades distribution of pore sizes and appropriate collocation of acidity,which have potential applications in catalysis and adsorption of large molecules.This review focus on some of the most recent results during the last decades.The techniques applied to synthesize different micro-mesoporous composite molecular sieves includes single template, dual template, crystallization of mesoporous walls, alkaline desilication, vapor-phase transport synthesis,and microwave radiation hydrothermal synthesis.

scholarly journals CFD Simulation of CO2 and Methane Adsorption at Various Temperature for MOF-5 using Dual-site and Single-site Langmuir Model

CFD Letters ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1-10
Author(s):  
Mohd Zul Amzar Zulkifli ◽  
Azfarizal Mukhtar ◽  
Muhammad Faizulizwan Mohamad Fadli ◽  
Anis Muneerah Shaiful Bahari ◽  
Akihiko Matsumoto ◽  
...  
Keyword(s):  
Energy Demand ◽  
Carbon Capture ◽  
Cfd Simulation ◽  
Co2 Adsorption ◽  
Minimum Energy ◽  
Packed Bed ◽  
Methane Adsorption ◽  
Adsorption Model ◽  
Porous Media Model ◽  
Dual Site

The annual increase in energy demand has led to an increase in greenhouse gas emissions, in particular CO2 emissions from the power generation industry. Carbon Capture and Utilization are technologies applied to capture CO2 gases and transform the gases into a different energy source. The adsorption technology to capture CO2 gases was chosen due to the minimum energy consumption and low costs required for an industrial application for sustainability. Metal-Organic Framework (MOF) has a reasonably high CO2 adsorption capability. It has been applied as an adsorbent for capturing and storing CO2. In this study, a comparison of CFD simulation with experimental CO2 and methane adsorption values in solid adsorbent beds containing MOF-5 at various temperatures was presented. The simulation was performed using 2D and 3D models from 0℃ at STP to 130℃ for CO2 and methane gas molecules. In addition, the isothermal and kinetic adsorption model was added to the simulations. This includes Single- and Dual-Site Langmuir adsorption isotherm and Linear Driving Force. The porous media model was then activated to imitate packed bed adsorbent and measured the pressure drop from the simulation. The results showed that the CO2 adsorption values of MOF-5 decrease as the adsorbent temperature increases. There was a decline of 0.002 mmol/g of adsorbed CO2 molecules per 10-kelvin difference. The CO2 adsorption value was 0.53 mmol/g at STP and 1.15 mmol/g for CH4 at STP. Both CO2 and CH4 adsorption were used to suggest optimal CO2 adsorption for the Pressure Swing Adsorption cycle.

scholarly journals Evaluation of Sorbent Sampling and Analysis Procedures for Acetone in Workplace Air: Variations of Concentration and Relative Humidity

2019 ◽  
Vol 64 (1) ◽  
pp. 96-105
Author(s):  
Jhy-Charm Soo ◽  
Ryan F Lebouf ◽  
William P Chisholm ◽  
John Nelson ◽  
Jennifer Roberts ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Silica Gel ◽  
Molecular Sieve ◽  
Mass Loading ◽  
Carbon Molecular Sieve ◽  
Humidity Effect ◽  
Atmosphere System ◽  
Acetone Adsorption ◽  
Workplace Air ◽  
Carbonaceous Sorbents

Abstract This study experimentally evaluates the performance of different sorbent tubes for sampling acetone vapor in workplace air. A dynamic atmosphere system produced an acetone alone and a mixture with other analytes containing ~73, 483, and 1898 µg acetone mass loading at 25, 50, and 75% relative humidity (RH) at 25°C. Sorbent samples were analyzed in accordance with OSHA Method 69 (Carbosieve S-III) and NMAM 1501, modified to use Anasorb 747 sorbent. Both methods were modified to include the additional analytes. Additional extraction procedures with and without 1% dimethylformamide and anhydrous magnesium sulfate were included in the modified NMAM 1501 using Anasorb 747. Silica gel sorbent tubes analyzed according to NMAM 2027 were included. There were significant reductions in the recovery of acetone from both Anasorb 747 and Carbosieve S-III collected from air at 75% RH, relative to collection at 25 or 50% RH at very low loading compared with that of samples collected at mid to high loading. Silica gel provided a consistent recovery of acetone at all RHs and in the presence of other chemical interferences at 75% RH. The likely cause of mass dependence may arise from the humidity effect on acetone adsorption onto both beaded active carbon and carbon molecular sieve either in sampling or in analysis. The present study confirms not only previous observations but also adds to the literature showing carbonaceous sorbents are not well suited for sampling ketones at high humidity and low concentration.

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