scholarly journals Increasing Permeability of Coal Seam and Improving Gas Drainage Using a Liquid Carbon Dioxide Phase Transition Explosive Technology

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Wenrui He ◽  
Fulian He ◽  
Kun Zhang ◽  
Yongqiang Zhao ◽  
Hengzhong Zhu
Keyword(s):  
Phase Transition ◽  
Carbon Dioxide ◽  
Numerical Simulation ◽  
Blast Hole ◽  
Liquid Carbon ◽  
Gas Drainage ◽  
Liquid Carbon Dioxide ◽  
Drainage Hole ◽  
Drainage Effect ◽  
Coal Damage

The low permeability of coal seams makes gas drainage difficult in lots of coal mines. This study presents a low-temperature, safe, and efficient liquid carbon dioxide phase transition explosive technology (LCDPTET) to increase the permeability of coal, thereby improving the efficiency of gas drainage and eliminating the dangers of coal and gas outburst. Meanwhile, an integrated approach for experimental determination, numerical simulation, and field testing was applied to study the damage ranges of coal and to determine a reasonable spacing between the gas drainage hole and blast hole. A numerical simulation model of liquid carbon dioxide phase transition explosion (LCDPTE) was built, and the damage index M was introduced to analyze the degree and range of coal damage after explosion at different spacings between the blast hole and the gas drainage hole. Furthermore, another aim was the assessment of the permeability changes and comparison of the gas drainage effects of different borehole spacings. The results showed that as the borehole spacing became smaller, the degree of coal damage around the gas drainage hole increased, and the gas drainage effect improved. However, to avoid the collapse of the gas drainage hole, the gas drainage holes should not be located in the crushing zone caused by LCDPTE. Based on the numerical analysis conducted to guide the borehole arrangement of the field test, the latter was carried out to study the increasing ranges of permeability of coal and the drainage effect after explosion. The results indicated that LCDPTET could greatly improve the permeability of the coal seam and gas drainage efficiency. In addition, this new technology could not only improve the safety and efficiency of mine production but could also turn carbon dioxide into an effective energy source worthy of popularization and application.

scholarly journals Mechanism Analysis of Liquid Carbon Dioxide Phase Transition for Fracturing Rock Masses

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2909 ◽  
Author(s):  
Feng Gao ◽  
Leihu Tang ◽  
Keping Zhou ◽  
Yanan Zhang ◽  
Bo Ke
Keyword(s):  
Phase Transition ◽  
Carbon Dioxide ◽  
High Pressure ◽  
Initial Stress ◽  
Initial Pressure ◽  
Initial Crack ◽  
Stress Waves ◽  
Mechanism Analysis ◽  
Liquid Carbon ◽  
Liquid Carbon Dioxide

The technique of breaking rocks using carbon dioxide phase transition technology is being widely applied in current research. This article combines theoretical and practical methods to analyze the mechanism by which high-pressure gas breaks rock at different stages. Using the observation that liquid carbon dioxide forms a high-pressure jet from release holes at the moment of release, a formula for calculating the initial pressure on the wall in the direction of release was obtained, and the pattern of initial crack formation on the borehole wall under different initial stress conditions was examined. An experiment using carbon dioxide phase transition technology to fracture rock without an initial stress field was conducted. The mechanism of generation and expansion of subsequent cracks under stress waves and high-pressure gas was analyzed, and the formula for calculating crack propagation radius under stress waves was obtained. The results suggested that under the quasi-static action of high-pressure gas, cracks begin to develop when the stress intensity factor KI at the crack tip is equal to or greater than the fracture toughness KIC of the rock.

Effect of liquid carbon dioxide phase change fracturing technology on gas drainage

2017 ◽  
Vol 10 (14) ◽  
Author(s):  
Hai-dong Chen ◽  
Zhao-feng Wang ◽  
Ling-ling Qi ◽  
Feng-hua An
Keyword(s):  
Carbon Dioxide ◽  
Phase Change ◽  
Liquid Carbon ◽  
Gas Drainage ◽  
Liquid Carbon Dioxide

scholarly journals Positive Phase Pressure Function and Pressure Attenuation Characteristic of a Liquid Carbon Dioxide Blasting System

Energies ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 4134
Author(s):  
Bo Ke ◽  
Keping Zhou ◽  
Gaofeng Ren ◽  
Ji Shi ◽  
Yanan Zhang
Keyword(s):  
Phase Transition ◽  
Carbon Dioxide ◽  
High Pressure ◽  
Impact Pressure ◽  
Positive Phase ◽  
Liquid Carbon ◽  
Edge Zone ◽  
Liquid Carbon Dioxide ◽  
The Impact ◽  
Phase Pressure

As environmental requirements become more stringent, the liquid carbon dioxide blasting system is one of the non-explosive blasting technologies that, with low tensile stress energy, will replace the chemical explosive blasting technology, and the impact pressure characteristic of high-pressure fluid is a crucial factor in the process of rock breaking. To further investigate the impact and pressure attenuation characteristics of high-pressure fluid during the phase transition of liquid carbon dioxide blasting system, the pressure curves of high-pressure fluid in liquid carbon dioxide blasting systems at different distances were measured in the laboratory. Based on the mechanism analysis of phase transition kinetics, the initial jet velocity of the four experiments was calculated, and the rationality of results was verified by the Bernoulli equation. The general expression of the positive phase pressure–time function was proposed, and the idealized impact pressure curve can be divided into five stages. The impact pressure field of the liquid carbon dioxide blasting system can be divided into three areas at different distances: the explosive jet impact zone, the jet edge zone and the shock wave action zone, and the pressure–contrast distance fitting equation of the liquid carbon dioxide blasting system were obtained.

scholarly journals Numerical Simulation for Optimum Seeding Operation Using Liquid Carbon Dioxide

2005 ◽  
Vol 60 (5) ◽  
pp. 901-904 ◽  
Author(s):  
Misato NAGATA ◽  
Kenji WAKIMIZU ◽  
Koji NISHIYAMA ◽  
Norihiko FUKUTA ◽  
Taichi MAKI
Keyword(s):  
Carbon Dioxide ◽  
Numerical Simulation ◽  
Liquid Carbon ◽  
Liquid Carbon Dioxide

scholarly journals Research on Initiation of Carbon Dioxide Fracturing Pipe Using the Liquid Carbon Dioxide Phase-Transition Blasting Technology

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 521
Author(s):  
Jieqin Xia ◽  
Bin Dou ◽  
Hong Tian ◽  
Jun Zheng ◽  
Guodong Cui ◽  
...  
Keyword(s):  
Phase Transition ◽  
Carbon Dioxide ◽  
Empirical Model ◽  
Strain Curve ◽  
Constant Stress ◽  
Liquid Carbon ◽  
Liquid Carbon Dioxide ◽  
Strength Failure ◽  
Shear Plate ◽  
Key Variables

Liquid carbon dioxide (L-CO2) phase-transition blasting technology (LCPTB) has caused wide concern in many fields, but there is a lack of research on the initiation of the carbon dioxide fracturing pipe. Studies regarding the carbon dioxide fracturing pipe initiation are critical for controlling and optimizing the LCPTB. Therefore, in this article, a series of exploratory experiments of carbon dioxide blasting were carried out to investigate the qualitative and quantitative relationships between the carbon dioxide fracturing pipe initiation and the three key variables (the filling mass of liquid carbon dioxide (L-CO2) (X1), the amount of chemical heating material (X2) and the thickness of the constant-stress shear plate (X3)). The failure mechanisms of three variables on the phase-transition blasting process of a carbon dioxide fracturing pipe was analyzed qualitatively based on experiment temperature, strain curve and failure form of constant-stress shear plate. An empirical model between the carbon dioxide fracturing pipe initiation (Y) and the three key variables (X1, X2, X3) was obtained after processing experiment result data quantitatively. Based on the phase-transition and blasting process of carbon dioxide, two methods, the Viral–Han–Long (VHL) equation of gas state (EOS) and the strength-failure method were used to calculate the blasting pressure and determine the failure mode of the fracturing pipe. The proposed blasting empirical model can be used to optimize the structural design of carbon dioxide fracturing pipes, guide on-site carbon dioxide blasting operations and further achieve the best blasting effect of LCPTB, so this work can enable LCPTB to be better applied to practical projects.

Permeability enhancement and porosity change of coal by liquid carbon dioxide phase change fracturing

2021 ◽  
Vol 287 ◽  
pp. 106106
Author(s):  
Xianfeng Liu ◽  
Baisheng Nie ◽  
Kunyong Guo ◽  
Chengpeng Zhang ◽  
Zepeng Wang ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Phase Change ◽  
Liquid Carbon ◽  
Liquid Carbon Dioxide ◽  
Porosity Change ◽  
Permeability Enhancement
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