Study of the Influence of Biodegradation on Coal Micro-Nano Pore Structure Using Low-Temperature N2 Adsorption

2021 ◽  
Vol 21 (1) ◽  
pp. 720-726
Author(s):  
Hongli Kang ◽  
Xiangrong Liu ◽  
Zaiwen Yang ◽  
Shunsheng Zhao ◽  
Zheng Yang

An experimental study of biodegradation of Shenmu coal was carried out by using Ochrobactrum cytisi, Novospingobium naphthalenivorans, Alcaligenes faecalis and Pseudomonas fluorescens. The micro-nano pore structure of coal samples before and after biodegradation was studied by low-temperature N2 adsorption. For biodegraded coal, the results showed that micropores and mesopores are primarily open pores with good connectivity, including parallel plate pores and cylinder pores with two open ends; the specific surface area of biodegraded coal decreased from 2.2174 m2/g to 1.6255˜2.0537 m2/g, and the pore size of the coal biodegraded by the four bacteria decreased following biodegradation from 250 nm to 170˜200 nm, which may be due to collapse of the coal structure due to the bacterial degradation. Coal biodegradation by the dominant bacterium P. fluorescens led to a diminished mesopore size and an increased number of smaller mesopores, with the smaller mesopores gradually taking on dominant roles.

2013 ◽  
Vol 395-396 ◽  
pp. 637-640
Author(s):  
Yi Yang ◽  
Zheng Ping Wang ◽  
Ling Meng ◽  
Lian Jun Wang

MIL-101, a metal-organic framework material, was synthesized by the high-temperature hydrothermal method. Triethylenetetramine (TETA) modification enabled the effective grafting of an amino group onto the surface of the materials and their pore structure. The crystal structure, micromorphology, specific surface area, and pore structure of the samples before and after modification were analyzed with an X-ray diffractometer, scanning electron microscope, specific surface and aperture tester, and infrared spectrometer. The carbon dioxide adsorption properties of the samples were determined by a thermal analyzer before and after TETA modification. Results show that moderate amino modification can effectively improve the microporous structure of MIL-101 and its carbon dioxide adsorption properties. After modification, the capacity of MIL-101 to adsorb carbon dioxide decreased only by 0.61 wt%, and a high adsorption capacity of 9.45 wt% was maintained after six cycles of adsorption testing at room temperature and ambient pressure.


2014 ◽  
Vol 962-965 ◽  
pp. 890-898
Author(s):  
Jin Ping Li ◽  
Da Zhen Tang ◽  
Ting Xu Yu ◽  
Gang Sun

Pore structure characteristics and the effect of lithotype and maceral on pore for three types of high-volatile bituminous coals from Binchang area were investigated by combined low-temperature nitrogen adsorption/desorption, nuclear magnetic resonance (NMR), scanning electron microscope (SEM) and maceral analysis. The low temperature N2 adsorption/desorption test results show that: micropores are more abundant than transitional pores with high BET surface area; two types of pore structures can be identified by adsorption/desorption isotherms; Pore morphology is mainly represented by well-connected, ink-bottled, cylindrical and parallel plate pores. NMR T2 distributions at full saturated condition are apparent or less obvious trimodal and three types of T2 distributions are identified; Seepage pores are better developed when compared with the middle-high rank coal. Further research found that the three coal lithotypes are featured by remarkably different pore structure characteristics and maceral contents of coal are linearly correlated to some of pore structure parameters.


Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Weiwei Liu ◽  
Kun Zhang ◽  
Qianwen Li ◽  
Zhanhai Yu ◽  
Sihong Cheng ◽  
...  

Due to the specificity of the geological background, terrestrial strata are widely distributed in the major hydrocarbon-bearing basins in China. In addition, terrestrial shales are generally featured with high thickness, multiple layers, high TOC content, ideal organic matter types, and moderate thermal evolution, laying a solid material foundation for hydrocarbon generation. However, the quantitative characterization study on their pore structure remains inadequate. In this study, core samples were selected from the Middle Jurassic Lianggaoshan Formation in the southeastern Sichuan Basin of the Upper Yangtze Region for analyses on its TOC content and mineral composition. Besides, experiments including oil washing, the adsorption/desorption of CO2 and nitrogen, and high-pressure mercury pressure experiments were carried out. The pore structure of different petrographic types of terrestrial shales can be accurately and quantitatively characterized with these works. The following conclusions were drawn: for organic-rich mixed shales and organic-rich clay shales, the TOC content is the highest; the pore volume, which is primarily provided by macropores and specific surface area, which is provided by mesopores, was the largest, thus providing more space for shale oil and gas reservation. The pores take on a shape either close to a parallel plate slit or close to or of an ink bottle. For organic-matter-bearing shales, both the pore volume and specific surface area are the second-largest and are provided by the same sized pores with organic-rich mixed shales. Its pores take on a shape approximating either a parallel plate slit or an ink bottle. Organic-matter-bearing mixed shales have the lowest pore volume and specific surface area; its pore volume is primarily provided by macropores, and the specific surface area by mesopores and the shape of the pores are close to an ink bottle.


2019 ◽  
Vol 176 ◽  
pp. 312-320 ◽  
Author(s):  
Peiqiang Zhao ◽  
Xixin Wang ◽  
Jianchao Cai ◽  
Miao Luo ◽  
Jin Zhang ◽  
...  

2019 ◽  
Vol 350 ◽  
pp. 15-25 ◽  
Author(s):  
Zhenyang Wang ◽  
Yuanping Cheng ◽  
Yuxiao Qi ◽  
Ranpeng Wang ◽  
Liang Wang ◽  
...  

Clay Minerals ◽  
1977 ◽  
Vol 12 (1) ◽  
pp. 1-9 ◽  
Author(s):  
E. Paterson

AbstractLow temperature nitrogen adsorption has been used to study the external and internal structure of a number of allophanic soil clays. The results indicate that allophane, in addition to having pores in the intermediate size range (2–10 nm radius), contains micropores of < 1 nm radius. The occurrence of hitherto unreported micropores in allophanic clays has necessitated re-evaluation of the validity of specific surface area measurements.


Minerals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 377
Author(s):  
Zhelin Wang ◽  
Xuewei Jiang ◽  
Mao Pan ◽  
Yongmin Shi

Fractal dimension is a critical parameter to evaluate the heterogeneity of complex pore structure in tight sandstone gas and other low permeability reservoirs. To quantify the fractal dimension of tight sandstone at various pore size classes and evaluate their implications on mineral composition and nano pore structure parameters, we conducted an integrated approach of N2 adsorption/desorption experiment (N2-GA), X-ray diffraction (X-RD), and field emission scanning electron microscopy (FE-SEM) on Sulige tight sandstone reservoirs. By comparing the nine types of fractal dimensions calculated from N2 adsorption data, we put forward the concept of “concentrated” fractal dimensions and “scattered” fractal dimensions (DN2, DN3, DN5, DN7 and DN8) for the first time according to its concentration extent of distribute in different samples. Result shows that mineral composition has a significant influence of a different level on specific surface area (SSA), pore volume (PV), and fractal dimensions (DN), respectively, where the “scattered” fractal dimension is more sensitive to certain specific property of the reservoir, including mineral content and the specific surface area contribution rate (Sr) of type II mesopores (Mesopore-II: 10~50nm). In addition, three type of hysteresis loops were distinguished corresponding to different pore shape combination of N2-GA isotherm curve, which reveals that pore structure heterogeneity is mainly controlled by inkbottle-shaped pores and the volume contribution rate (Vr) of mesopores in this study area. These findings could contribute to a better understanding of the controlling effect of pore heterogeneity on natural gas storage and adsorption.


Equipment ◽  
2006 ◽  
Author(s):  
E. N. Pis'mennyi ◽  
V. A. Rogachev ◽  
A. M. Terekh ◽  
Georgiy Polupan ◽  
I. Carvajal-Mariscal ◽  
...  

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