scholarly journals Influence of Nanopore Structure Deformation on Gas Migration in Coal

ACS Omega ◽  
2021 ◽  
Author(s):  
Xiaofeng Ji ◽  
Dangyu Song ◽  
Wenfang Shi ◽  
Yanfei Li

2020 ◽  
Vol 10 (14) ◽  
pp. 4997
Author(s):  
Linlin Wang ◽  
Zhengjiang Long

The coal structure deformation attributed to actions of tectonic stresses can change characteristics of nanopore structure of coals, affecting their CO2 adsorption. Three tectonically deformed coals and one undeformed coal were chosen as the research objects. The isotherm adsorption experiments of four coal specimens were carried out at the temperature of 35 °C and the pressure of 0 to 7 MPa. Nanopore structures were characterized using the liquid nitrogen adsorption method. The results show that there exist maximum values of excess and absolute adsorption capacity, which increase with increasing coal deformation degree. As the degree of coal deformation increases, the pore volume and specific surface area present an obvious increasing trend in the case of micropores, exhibiting an increase at first (cataclastic coal and ganulitic coal) and then stabilization (crumple coal), in the case of mesopores, and showing a gradual decrease in the case of macropores. The mesopores are the key factor of CO2 adsorption of tectonically deformed coals, followed by the micropores and the limited effect of macropores at the strong coal deformation stage.



1990 ◽  
Vol 26 (10) ◽  
pp. 2425-2434 ◽  
Author(s):  
Roger Thunvik


Author(s):  
Yu.Ya. Bolshakov ◽  
◽  
E.Yu. Neyolova ◽  
Keyword(s):  


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Alexander H. Frank ◽  
Robert van Geldern ◽  
Anssi Myrttinen ◽  
Martin Zimmer ◽  
Johannes A. C. Barth ◽  
...  

AbstractThe relevance of CO2 emissions from geological sources to the atmospheric carbon budget is becoming increasingly recognized. Although geogenic gas migration along faults and in volcanic zones is generally well studied, short-term dynamics of diffusive geogenic CO2 emissions are mostly unknown. While geogenic CO2 is considered a challenging threat for underground mining operations, mines provide an extraordinary opportunity to observe geogenic degassing and dynamics close to its source. Stable carbon isotope monitoring of CO2 allows partitioning geogenic from anthropogenic contributions. High temporal-resolution enables the recognition of temporal and interdependent dynamics, easily missed by discrete sampling. Here, data is presented from an active underground salt mine in central Germany, collected on-site utilizing a field-deployed laser isotope spectrometer. Throughout the 34-day measurement period, total CO2 concentrations varied between 805 ppmV (5th percentile) and 1370 ppmV (95th percentile). With a 400-ppm atmospheric background concentration, an isotope mixing model allows the separation of geogenic (16–27%) from highly dynamic anthropogenic combustion-related contributions (21–54%). The geogenic fraction is inversely correlated to established CO2 concentrations that were driven by anthropogenic CO2 emissions within the mine. The described approach is applicable to other environments, including different types of underground mines, natural caves, and soils.



Nano Letters ◽  
2021 ◽  
Author(s):  
Shuguang Wang ◽  
Peng Zhou ◽  
Lei Zhou ◽  
Fan Lv ◽  
Yingjun Sun ◽  
...  


2021 ◽  
Vol 130 (2) ◽  
Author(s):  
Jyothsna Palle ◽  
Satyavani Nittala ◽  
Kiranmai Samudrala


2021 ◽  
Vol 13 (12) ◽  
pp. 2263
Author(s):  
Dongfeng Jia ◽  
Weiping Zhang ◽  
Yuhao Wang ◽  
Yanping Liu

As fundamental load-bearing parts, the cylindrical steel structures of transmission towers relate to the stability of the main structures in terms of topological relation and performance. Therefore, the periodic monitoring of a cylindrical steel structure is necessary to maintain the safety and stability of existing structures in energy transmission. Most studies on deformation analysis are still focused on the process of identifying discrepancies in the state of a structure by observing it at different times, yet relative deformation analysis based on the data acquired in single time has not been investigated effectively. In this study, the piecewise cylinder fitting method is presented to fit the point clouds collected at a single time to compute the relative inclination of a cylindrical steel structure. The standard deviation is adopted as a measure to evaluate the degree of structure deformation. Meanwhile, the inclination rate of each section is compared with the conventional method on the basis of the piecewise cylinder fitting parameters. The validity and accuracy of the algorithm are verified by real transmission tower point cloud data. Experimental results show that the piecewise cylinder fitting algorithm proposed in this research can meet the accuracy requirements of cylindrical steel structure deformation analysis and has high application value in the field of structure deformation monitoring.





1989 ◽  
Author(s):  
P. Drecq
Keyword(s):  


2018 ◽  
Vol 224 ◽  
pp. 02061
Author(s):  
Irina Troyanovskaya ◽  
Anton Kalugin

According to the safety requirements, all protective devices of tractor units are subject to obligatory certification. One of the main means of protecting the operator during overturning is ROPS system. In accordance with GOST (National State Standard), a performance check of ROPS protective structures is carried out on basis of full-scale tests. The purpose of the presented study is to develop the experimental procedure and to obtain the performance check result of ROPS protective device of the tractor unit’s cabin using B10 bulldozer manufactured by the Chelyabinsk Tractor Plant as an example. The tests were carried out at the Ural Test Center NATI. For this purpose, a special bedplate was used, allowing to test the protective cabins of tractors with the total mass of up to 110 tons. The hydraulic system of the bedplate allowed to carry out the process of lateral loading of ROPS step by step, where each step corresponded to the 10 mm structure deformation. The applied load and structure deformation were recorded at each step. The energy accumulated by the structure was calculated as the area under the stress-strain curve. The energy U = 40867 J, which was required according to GOST, was accumulated during lateral deformation Δ = 270 mm. The force constituted Fy = 243 kN. After removing the lateral load, the structure was subjected to the vertical static and longitudinal loading. During the whole experiment of ROPS protective device, repairs, deformation corrections and adjustments were not allowed. The test results of ROPS structure of B10 bulldozer cabin showed compliance with the GOST safety requirements. During ROPS deformation, penetration of the protective structure elements into the driver’s limited zone was not observed.



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