scholarly journals Method for designing the optimal sealing depth in methane drainage boreholes to realize efficient drainage

2021 ◽  
Author(s):  
Minghao Yi ◽  
Liang Wang ◽  
Congmeng Hao ◽  
Qingquan Liu ◽  
Zhenyang Wang
Keyword(s):  
Drainage System ◽  
Surrounding Rock ◽  
High Concentration ◽  
Failure Characteristics ◽  
Coal Mine Methane ◽  
Methane Drainage ◽  
Sealing Material ◽  
Sealing Performance ◽  
Key Factor ◽  
Quantitative Analysis Method

AbstractThe purpose of underground methane drainage technology is to prevent methane disasters and enable the efficient use of coal mine methane (CMM), and the sealing depth is a key factor that affects the performance of underground methane drainage. In this work, the layouts of in-seam and crossing boreholes are considered to analyze the stress distribution and failure characteristics of roadway surrounding rock through a numerical simulation and field stress investigation to determine a reasonable sealing depth. The results show that the depths of the plastic and elastic zones in two experimental coal mines are 16 and 20 m respectively. Borehole sealing minimizes the air leakage through the fractures around the roadway when the sealing material covers the failure and plastic zones, and the field test results for CMM drainage at different sealing depths indicate that the CMM drainage efficiency increases with increasing sealing depth but does not change once the sealing depth exceeds the plastic zone. Moreover, sealing in the high-permeability roadway surrounding rock does not have a strong influence on the borehole sealing performance. Considering these findings, a new CMM drainage system for key sealing in the low-permeability zone was developed that is effective for improving the CMM drainage efficiency and prolonging the high-concentration CMM drainage period. The proposed approach offers a valuable quantitative analysis method for selecting the optimum sealing parameters for underground methane drainage, thereby improving considerably the drainage and utilization rates of CMM.

scholarly journals Optimal design method of sealing depth in methane drainage boreholes to realize efficient drainage

2021 ◽  
Author(s):  
Minghao Yi ◽  
Liang Wang ◽  
Congmeng Hao ◽  
Qingquan Liu ◽  
Zhenyang Wang
Keyword(s):  
Plastic Zone ◽  
Design Method ◽  
Drainage System ◽  
High Concentration ◽  
Coal Mine Methane ◽  
Methane Drainage ◽  
Sealing Material ◽  
Sealing Performance ◽  
Key Factor ◽  
Quantitative Analysis Method

Abstract The purpose of underground methane drainage technology is to eliminate methane disasters and enable the efficient use of coal mine methane (CMM). The sealing depth is a key factor that affects the underground methane drainage performance. In this work, the layouts of bedding and crossing boreholes were considered to analyze the stress distribution and failure characteristics of roadway surrounding rocks through a numerical simulation and field stress investigation to determine a reasonable sealing depth. The results demonstrated that the depths of the plastic zone and elastic zone in the Xutuan and Qinan coal mines were 16 m and 20 m, respectively. Borehole sealing could minimize the air leakage through the fractures around the roadway when the sealing material covered the failure and plastic zones. In addition, the field test results of CMM drainage at different sealing depths indicated that the CMM drainage efficiency increased with an increase in the sealing depth and not change when the sealing depth exceeded the plastic zone. Moreover, sealing in the high permeability roadway surrounding rock did not strongly influence the borehole sealing performance. Considering these findings, a new CMM drainage system for a specific sealing depth and length was developed, which could effectively improve the CMM drainage efficiency and prolong the high concentration CMM drainage period. The proposed approach can be a valuable quantitative analysis method to select the optimized sealing parameters for underground methane drainage, which can considerably improve the drainage and utilization rates of CMM.

Numerical Simulation Study on Battery-Casing Sealing Considering Rubber Aging

2020 ◽  
Vol 36 (6) ◽  
pp. 955-969
Author(s):  
Yijie Huang ◽  
Fei Guo ◽  
Yuchao Ke ◽  
Fangyong Wu ◽  
Xiaohong Jia ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Porous Media ◽  
Circular Arc ◽  
Sealing Material ◽  
Sealing Performance ◽  
Porous Media Model ◽  
New Energy ◽  
Key Factor ◽  
Grid Independence ◽  
New Energy Vehicles

ABSTRACTBattery-casing sealing is the key factor for secure travel of new energy vehicles. We constructed a relatively accurate mechanical-simulation model by selecting a constitutive model, analyzing the influence of thermal elongation, verifying the grid-independence and comparing numerically by the pressure-measurement film on the basis of studying the physical performance of a certain type of sealing material that had been used in battery-casings after aging. Based on a porous-media model and combined with changes of macroscopic and microscopic contact characteristics of materials at different times after aging, the evolution rule of sealing performance with time was analyzed quantitatively by calculating the leakage. By analyzing the structure of circular arc bulge on the surface of sealing material, the radius of circular arc bulge with better sealing performance was obtained, which could reduce the leakage of sealing structure during the material’s lifecycle.

scholarly journals The Security of Energy Supply from Internal Combustion Engines Using Coal Mine Methane—Forecasting of the Electrical Energy Generation

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3049
Author(s):  
Marek Borowski ◽  
Piotr Życzkowski ◽  
Klaudia Zwolińska ◽  
Rafał Łuczak ◽  
Zbigniew Kuczera
Keyword(s):  
Coal Mine ◽  
Predictive Models ◽  
Coalbed Methane ◽  
Internal Combustion Engines ◽  
Drainage System ◽  
Production Capacity ◽  
Methane Combustion ◽  
Economic Benefits ◽  
Electricity Production ◽  
Coal Mine Methane

Increasing emissions from mining areas and a high global warming potential of methane have caused gas management to become a vital challenge. At the same time, it provides the opportunity to obtain economic benefits. In addition, the use of combined heat and power (CHP) in the case of coalbed methane combustion enables much more efficient use of this fuel. The article analyses the possibility of electricity production using gas engines fueled with methane captured from the Budryk coal mine in Poland. The basic issue concerning the energy production from coalbed methane is the continuity of supply, which is to ensure the required amount and concentration of the gas mixture for combustion. Hence, the reliability of supply for electricity production is of key importance. The analysis included the basic characterization of both the daily and annual methane capture by the mine’s methane drainage system, as well as the development of predictive models to determine electricity production based on hourly capture and time parameters. To forecast electricity production, predictive models that are based on five parameters have been adopted. Models were prepared based on three time variables, i.e., month, day, hour, and two values from the gas drainage system-capture and concentration of the methane. For this purpose, artificial neural networks with different properties were tested. The developed models have a high value of correlation coefficient. but showed deviations concerning the very low values persisting for a short time. The study shows that electricity production forecasting is possible, but it requires data on many variables that directly affect the production capacity of the system.

Effects of permeability anisotropy on coal mine methane drainage performance

2021 ◽  
Vol 86 ◽  
pp. 103733
Author(s):  
Zhen Lou ◽  
Kai Wang ◽  
Jie Zang ◽  
Wei Zhao ◽  
Binbin Qin ◽  
...  
Keyword(s):  
Coal Mine ◽  
Coal Mine Methane ◽  
Methane Drainage ◽  
Permeability Anisotropy

scholarly journals Experimental Study on the Ratio of Similar Materials in Weak Surrounding Rock Based on Orthogonal Design

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Pengfei Jiao ◽  
Xiao Zhang ◽  
Xinzhi Li ◽  
Bohong Liu ◽  
Haojie Zhang
Keyword(s):  
Model Test ◽  
Orthogonal Design ◽  
Surrounding Rock ◽  
Similar Material ◽  
Geomechanical Model ◽  
Geomechanical Model Test ◽  
Geological Conditions ◽  
Key Factor ◽  
Similar Materials ◽  
Weak Surrounding Rock

In the aspect of stability analysis of tunneling engineering, geomechanical model test is an important research method. A similar material is the prerequisite for the success of geomechanical model test. In the field of major engineering applications, a variety of similar materials are prepared for different geological conditions of surrounding rock and applied in some major engineering. With the use of standard sand, fine sand, and silt clay as materials, similar materials for weak surrounding rock were developed. Based on the orthogonal design method, through the direct shear test, the range analysis and variance analysis of various factors affecting the physical and mechanical parameters of weak surrounding rock are carried out. The results show similar material can meet the requirements in weak surrounding rock. Standard sand is the key factor that influences the internal friction angle of similar materials, and silt clay is the key factor affecting the cohesion of similar materials. Similar materials can meet the elastic modulus and severe requirements of the weak surrounding rock and can be used for the weak surrounding rock engineering. The new type of similar material configuration is widely used in shallow buried tunnel entrance section and urban shallow buried excavation engineering, in addition to tunnel engineering in loess stratum, and the problems of engineering design and construction are solved through geomechanical model test.

scholarly journals Inhibitory effect of high leucine concentration on α-amylase secretion by pancreatic acinar cells: possible key factor of proteasome

2018 ◽  
Vol 38 (6) ◽  
Author(s):  
Long Guo ◽  
Baolong Liu ◽  
Chen Zheng ◽  
Hanxun Bai ◽  
Hao Ren ◽  
...  
Keyword(s):  
Amylase Activity ◽  
Acinar Cells ◽  
Inhibitory Effect ◽  
Proteasome Activity ◽  
Pancreatic Acinar Cells ◽  
Amylase Secretion ◽  
High Concentration ◽  
Amylase Release ◽  
Cholecystokinin Receptor ◽  
Key Factor

The present study aimed to investigate whether leucine affects the pancreatic exocrine by controlling the antisecretory factor (AF) and cholecystokinin receptor (CCKR) expression as well as the proteasome activity in pancreatic acinar cells of dairy calves. The pancreatic acinar cells were isolated from newborn Holstein bull calves and cultured using the Dulbecco’s modified Eagle’s medium/nutrient mixture F12 Ham’s liquid (DMEM/F12). There were six treatments of leucine dosage including 0 (control), 0.23, 0.45, 1.35, 4.05, and 12.15 mM, respectively. After culture for 3 h, the samples were collected for subsequent analysis. As the leucine concentration increased from 0 to 1.35 mM, the α-amylase activity in media decreased significantly (P<0.05), while further increase in leucine concentration did not show any decrease in α-amylase activity. Addition of leucine inhibited (P<0.05) the expression of AF and CCKR, and decreased the activity of proteasome (P<0.05) by 76%, 63%, 24%, 7%, and 9%, respectively. Correlation analysis results showed α-amylase secretion was negatively correlated with leucine concentration (P<0.01), and positively correlated with proteasome activity (P<0.01) and the expression of CCK1R (P<0.01) and AF (P<0.05). The biggest regression coefficient was showed between α-amylase activity and proteasome (0.7699, P<0.001). After inhibition of proteasome by MG-132, low dosage leucine decreased (P<0.05) the activity of proteasome and α-amylase, as well as the expression of CCK1R. In conclusion, we demonstrated that the high-concentration leucine induced decrease in α-amylase release was mainly by decreasing proteasome activity.

scholarly journals Safe water for all: A nature-based approach for cyanotoxin elimination from potable water

2020 ◽  
Vol 2 (7A) ◽  
Author(s):  
Sylvia Soldatou ◽  
Anjali Jaykumar ◽  
Abeysiri H.A.S.N ◽  
Pathmalal M. Manage ◽  
Ondřej Mašek ◽  
...  
Keyword(s):  
Sri Lanka ◽  
Kidney Disease ◽  
Crop Residues ◽  
Clean Energy ◽  
Cyanobacterial Blooms ◽  
Sri Lankan ◽  
High Concentration ◽  
Safe Water ◽  
Key Factor ◽  
Coconut Shells

Cyanobacterial blooms are a serious threat to public health and water quality due to the production of cyanotoxins as a result of nutrient pollution from industry, agriculture, domestic waste as well as global warming. The microcystins (MCs) are the most abundant cyanotoxins consisting of >200 analogues causing both acute and chronic toxicity, sometimes resulting in death. In Asian countries, such as Sri Lanka, reports of kidney disease are constantly increasing. Although no direct link between metal and pesticide contamination in water and kidney disease has been found, high concentration of cyanobacteria cells in drinking water wells implies that the nephrotoxic effects of cyanotoxins might play a key factor in the reports of Chronic Kidney Disease of unknown aetiology (CKDu) in Sri Lanka. Therefore, we propose a nature-based approach for water treatment which will study the hypotheses that cyanotoxins can cause CKDu. Sri Lankan bacterial isolates (Alcaligens sp., Roseateles sp., Bacillus sp., and Micrococcus sp.) known to degrade microcystins, were used to form biofilm on biochar from Sri Lankan crop residues, such as coconut shells. The immobilisation of the microbes was assessed via a high-throughput colourimetric assay, followed by monitoring the biodegradation rate of microcystins when added to the immobilised cultures. Biodegradation products were analysed and identified through molecular networking and quantified via LC-MS/MS. Ultimately, this project will provide safe water in line with UN Sustainable Development Goal 6.1 as well contributing in sustainable goals 7 (Affordable and Clean Energy), 11 (Sustainable Cities and Communities) and 12 (Responsible Production and Consumption).

scholarly journals Deformation Rules for Surrounding Rock in Directional Weakening of End Roofs of Thin Bedrocks and Ultrathick Seams

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Fei Liu ◽  
Zhanguo Ma ◽  
Yongsheng Han ◽  
Zhimin Huang
Keyword(s):  
Abutment Pressure ◽  
Main Roof ◽  
Stability Control ◽  
Surrounding Rock ◽  
Western China ◽  
Resource Exploitation ◽  
Failure Characteristics ◽  
Key Strata ◽  
Working Face ◽  
Geological Conditions

With the deployment of China’s energy strategy in the western regions, complex geological mining conditions such as thin bedrock and ultrathick seams in western China have caused a series of problems such as serious deformation of the surrounding rock at the ends of the working face and the increase in the lead abutment pressure of the roadways; the research on end roof deformation in the resource exploitation in western China has become one of the great demands of the industry. Based on the failure characteristics of rock mass, relying on the actual mining geological conditions of a coal mine in Inner Mongolia, the failure characteristics of the overlying rock strata under the influence of mining were simulated and analyzed using similar material simulation experiment, which intuitively reproduced the failure and deformation processes of the immediate roof, main roof, and key strata and revealed the mechanical mechanism of the directional weakening of the end roof. It is of great significance for the stability control of the surrounding rock at the end of the fully mechanized caving face in the thin bedrocks and ultrathick seams, reducing the abutment pressure of gate roadway and controlling the spontaneous combustion of residual coal in the goaf.

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