The mechanism of gas pressure and temperature dependent surface flashover in compressed gas involving gas adsorption

2021 ◽  
Vol 539 ◽  
pp. 148107
Author(s):  
Zhen Li ◽  
Shengtao Li ◽  
Haoming Xu ◽  
Guanghao Qu ◽  
Huan Niu ◽  
...  
Keyword(s):  
Gas Adsorption ◽  
Gas Pressure ◽  
Temperature Dependent ◽  
Surface Flashover ◽  
Compressed Gas

Understanding surface charge accumulation and surface flashover on spacers in compressed gas insulation

2018 ◽  
Vol 25 (4) ◽  
pp. 1152-1166 ◽  
Author(s):  
Chuanyang Li ◽  
Chuanjie Lin ◽  
Bo Zhang ◽  
Qi Li ◽  
Weidong Liu ◽  
...  
Keyword(s):  
Surface Charge ◽  
Charge Accumulation ◽  
Surface Flashover ◽  
Compressed Gas ◽  
Gas Insulation

scholarly journals Characteristics of gas pressure change during the freezing process of gas-containing coal

2022 ◽  
pp. 014459872110731
Author(s):  
Jun Liu ◽  
Yanzhao Wei ◽  
Wei Wang ◽  
Luwei Zhang ◽  
Jinqi Wu
Keyword(s):  
Coal Sample ◽  
Gas Adsorption ◽  
Gas Pressure ◽  
Shanxi Province ◽  
Freezing Process ◽  
Rapid Decline ◽  
Freezing Response ◽  
Response Characteristics ◽  
Soft Coal ◽  
Sample Tank

To investigate the characteristics of gas pressure changes during the freezing of gas-containing composite coal, an experimental device for determining the freezing response characteristics of gas-containing coal was independently designed. Coal samples with different firmness coefficients from the No. 3 coal seam in Yuxi Coal Mine in Jincheng, Shanxi Province, were selected to determine the different freezing response characteristics. The gas pressure evolved under different temperatures (-10 °C-15 °C-20 °C-25 °C-30 °C) and different adsorption equilibrium pressures (1.0 MPa, 1.5 MPa, 2.0 MPa). The research results reveal that, during the freezing process of the gas-containing coal sample, the gas pressure in the coal sample tank changed as a monotonously decreasing function and underwent three stages: rapid decline, decline, and slow decline. The relationship between the gas pressure of the coal sample tank and the freezing time is described by a power function. Low temperatures promoted gas adsorption. As the freezing temperature decreased, the decrease of gas pressure in the coal sample tank became faster. During the freezing process, the adsorption capacity of soft coal was larger, and the gas pressure of soft coal was lower.

Synthesis and Gas-Sensing Character of SnOx Cluster-Assembled Films

2006 ◽  
Vol 11-12 ◽  
pp. 599-602
Author(s):  
Takehiko Hihara ◽  
H. Matsukawa ◽  
Dong Liang Peng ◽  
K. Sumiyama
Keyword(s):  
Electrical Resistance ◽  
Cluster Size ◽  
Gas Sensing ◽  
Gas Pressure ◽  
Temperature Dependent ◽  
Gas Condensation ◽  
Potential Barriers ◽  
Transmission Electron ◽  
High Resolution Tem ◽  
Temperature Dependent Resistivity

Nanometric SnOx cluster-assembled films prepared by a plasma-gas-condensation cluster deposition apparatus have been examined by transmission electron microscopy (TEM) and electrical resistance. TEM observation showed that those clusters were almost spherical and size-monodispersive with a mean cluster size of 10 nm. The high-resolution TEM images indicated that the films were composed of randomly oriented nanocrystallites and that their surface roughness retained the traces of the original SnOx clusters. The electrical resistance of the SnOx cluster-assembled film decreased with decreasing partial O2 gas pressure. This result suggests that the intergranular potential barriers were responsible for the resisitvity variation. The activation energy estimated from the temperature-dependent resistivity was 0.75 eV for 330 K < T < 410 K under the partial O2 gas pressure of 0.02 MPa.

Experimental Investigation of the Influence of the Adsorption Gas on the Permeability Characteristics of the Coal Containing Gas

2012 ◽  
Vol 616-618 ◽  
pp. 190-196
Author(s):  
Deng Ke Wang ◽  
Jian Ping Wei ◽  
Le Wei ◽  
Heng Jie Qin
Keyword(s):  
Coal Sample ◽  
Gas Adsorption ◽  
Triaxial Compression ◽  
Axial Loading ◽  
Experimental System ◽  
Confining Pressure ◽  
Gas Pressure ◽  
Permeability Characteristics ◽  
Gas Seepage ◽  
Loading Case

A large number of laboratory experiments on the gas seepage characteristics by the self-developed gas-bearing coal triaxial compression experimental system and conducts the comparative analysis of the similarities and differences of the permeability among CO2, CH4 and N2. The results show that given the condition of constant gas pressure, the permeability of the coal sample decreases with the increase of the confining pressure; under the constant confining pressure, the permeability of the coal sample decreases with the increase of the gas pressure; gases of different adsorbabilities have different permeabilities. The stronger the gas adsorption is, the worse its permeability will be; in the axial loading case, the permeabilities of different gases all reduce firstly and increase afterward, showing the generally V-shaped variation law. The results are of certain theoretical values on the in-depth understanding of the migration law of the gas in coal seams.

Modeling Dry Wear of Piston Rod Sealing Elements of Reciprocating Compressors Considering Gas Pressure Drop Across the Dynamic Sealing Surface

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
A. Kaufmann ◽  
T. Lindner-Silwester ◽  
T. Antretter
Keyword(s):  
Numerical Model ◽  
Pressure Drop ◽  
Analytical Solution ◽  
Gas Pressure ◽  
Differential Pressure ◽  
Compressed Gas ◽  
Packing Rings ◽  
Packing Ring ◽  
Sealing Elements ◽  
Counter Surface

The wear of dynamic sealing elements, i.e., elements that seal against a moving counter-surface, is highly complex. In dry-running reciprocating compressors, these sealing elements, commonly referred to as packing rings, have to seal the compressed gas against the environment along the reciprocating rod. Since the packing rings' seal effect arises from the differential pressure to be sealed, it is of paramount importance to take into account the gas pressure drop across the dynamic sealing surface. This paper presents a numerical model that allows us to calculate how the wear of such a packing ring evolves with time. An analytical solution is used to verify the numerical model.

Experimental Study on Gas Pressure Effects on Gas Desorption Characteristic of Coal Seam

2013 ◽  
Vol 318 ◽  
pp. 367-370 ◽  
Author(s):  
Lin Chao Dai ◽  
Da Yong Lu ◽  
Zhen Liu
Keyword(s):  
Coal Seam ◽  
Gas Adsorption ◽  
Experimental System ◽  
Gas Pressure ◽  
Pressure Effects ◽  
Gas Content ◽  
Equilibrium Pressure ◽  
Gas Desorption ◽  
Exploitation And Utilization ◽  
The Impact

To further explore the impact of gas pressure on gas desorption and flowing law, the gas desorption experimental system designed autonomously is used to carry out studies on gas desorption experiment under different gas pressures. By data fitting, the relationship between gas desorption quantity and time is obtained and also established the model for gas desorption. The results show that: the gas desorption quantity curves is "The first half rises sharply, the latter half segment is gently rising and eventually becomes stabilized", and when the gas adsorption equilibrium pressure is the greater, the gas desorption amount is greater. And the formula can describe the gas desorption law well, the correlation coefficient R2 is above 0.97. The study provides an important theory reference to coal and gas outburst prediction, coal seam gas content prediction and its exploitation and utilization.

scholarly journals Experimental study on the influence of aerated gas pressure and confining pressure on low-rank coal gas adsorption process

2021 ◽  
pp. 014459872110310
Author(s):  
Ming Yang ◽  
Gaini Jia ◽  
Jianliang Gao ◽  
Jiajia Liu ◽  
Xuebo Zhang ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Coal Sample ◽  
Adsorption Process ◽  
Gas Adsorption ◽  
Confining Pressure ◽  
Gas Pressure ◽  
Pressure Point ◽  
Adsorbed Gas ◽  
Confining Pressures ◽  
Total Adsorption

To deeply study the variation characteristics of the gas content in the process of gas adsorption for coal samples under different gas pressures and confining pressures, low-field nuclear magnetic resonance technology was used to carry out experimental research on the gas adsorption of coal. The relationship between the T2 spectrum amplitude integral and the gas quantity was analyzed. The results show the following: (1) When the samples were inflated for 11 h at each gas pressure point (0.31, 0.74, 1.11, and 1.46 MPa), after ∼5 h of adsorption, the amount of adsorbed gas exceeded 85.0% of the total adsorption capacity; additionally, as the adsorption time increased, the amount of adsorbed gas gradually tended to stabilize. When the gas pressure was >1 MPa, the amount of adsorbed gas exceeded 90.0% of the total adsorption capacity; Higher the pressure of aerated gas, greater the gas pressure gradient or concentration gradient on the surface of the coal sample and the greater the driving force for gas molecules to seep or diffuse into the coal sample. (2) When the samples were inflated for 11 h at each confining pressure point (3, 4, 5, and 7 MPa), the adsorbed gas increased by ∼85.0% of the total adsorbed gas in the first 5 h. When the pressure was <5 MPa, the amount of adsorbed gas exceeded 85.0% of the total amount of adsorption; that is, the increase in adsorbed gas was the largest at ∼5 h in the adsorption process for the columnar coal sample under different confining pressures, and the increase was ∼5.0% from 7–11 h. When the large pores in the coal sample closed, the amount of gas that seeped into the deep part of the coal sample within the same aeration time was reduced.

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