scholarly journals Experimental Study on Methane Desorption from Lumpy Coal under the Action of Hydraulic and Thermal

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Dong Zhao ◽  
Dayuan Li ◽  
Yulin Ma ◽  
Zengchao Feng ◽  
Yangsheng Zhao
Keyword(s):  
Gas Flow ◽  
Water Pressure ◽  
Water Injection ◽  
Steam Injection ◽  
Gas Desorption ◽  
Pressure Water ◽  
Methane Desorption ◽  
Cbm Production ◽  
Injection Technology ◽  
Desorption Capacity

Moisture and thermal are the key factors for influencing methane desorption during CBM exploitation. Using high-pressure water injection technology into coalbed, new fractures and pathways are formed to transport methane. A phenomenon of water-inhibiting gas flow existed. This study is focused on various water pressures impacted on gas-adsorbed coal samples, and then the desorption capacity could be revealed under different conditions. And the results are shown that methane desorption capacity was decreased with the increase in water pressure at room temperature and the downtrend would be steady until water pressure was large enough. Heating could promote gas desorption capacity effectively, with the increasing of water injection pressures, and the promotion of thermal on desorption became more obvious. These results are expected to provide a clearer understanding of theoretical efficiency of heat water or steam injection into coalbed, and they can provide some theoretical and experimental guidance on CBM production and methane control.

scholarly journals Experimental Study on Methane Desorption from Lumpy Coal under the Action of Hydraulic and Thermal

2018 ◽  
Author(s):  
Dong Zhao ◽  
Dayuan Li ◽  
Yulin Ma ◽  
Zengchao Feng ◽  
Yangsheng Zhao
Keyword(s):  
Gas Flow ◽  
Water Pressure ◽  
Water Injection ◽  
Steam Injection ◽  
Gas Desorption ◽  
Pressure Water ◽  
Methane Desorption ◽  
Cbm Production ◽  
Injection Technology ◽  
Desorption Capacity

Moisture and thermal are the key factors for influencing methane desorption during CBM exploitation. Using high pressure water injection technology into coalbed, new fractures and pathways are formed to methane transport. It is existed a phenomenon of water inhibiting gas flow. This study is focused on various water pressures impacted on gas adsorbed coal samples, then the desorption capacity could be revealed under different conditions. And the results are shown that methane desorption capacity was decreased with water pressure increased at room temperature and the downtrend would be steady until water pressure was large enough. Heating could promote gas desorption capacity effectively, with the increasing of water injection pressures, the promotion of thermal on desorption became more obvious. These results are expected to provide a clearer understanding of theoretical efficiency of heat water or steam injection into coalbed, they can provide some theoretical and experimental guidance on CBM production and methane control.

scholarly journals Experimental Study on Methane Desorption with the Coupling Effects of High Pressure Water and Thermal

2017 ◽  
Author(s):  
Dong Zhao ◽  
Dayuan Li ◽  
Yulin Ma ◽  
Zengchao Feng ◽  
Yangsheng Zhao
Keyword(s):  
High Pressure ◽  
Gas Flow ◽  
Water Pressure ◽  
Water Injection ◽  
Key Factors ◽  
Gas Desorption ◽  
Pressure Water ◽  
Methane Desorption ◽  
Injection Technology ◽  
Desorption Capacity

Moisture and thermal are the key factors for influencing methane desorption during CBM exploitation. Using high pressure water injection technology into coalbed, new fractures and pathways are formed to methane transport. It is existed a phenomenon of water inhibiting gas flow. This study is focused on various water pressures impacted on gas adsorbed coal samples, then the desorption capacity could be revealed under different conditions. And the results are shown that methane desorption capacity was decreased with water pressure increased at room temperature and the downtrend would be steady until water pressure was large enough. Heating could promote gas desorption capacity effectively, with the increasing of water injection pressures, the promotion of thermal on desorption became more obvious. There are the others effects on methane desorption capacity influenced by water injection and thermal.

scholarly journals Methane Desorption Characteristics of Coal at Different Water Injection Pressures Based on Pore Size Distribution Law

Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2345 ◽  
Author(s):  
Dong Zhao ◽  
Tao Gao ◽  
Yulin Ma ◽  
Zengchao Feng
Keyword(s):  
Pore Size ◽  
Water Pressure ◽  
Water Injection ◽  
Volume Distribution ◽  
Residual Water ◽  
Distribution Law ◽  
Flow Process ◽  
Gas Desorption ◽  
Methane Desorption ◽  
Injection Pressures

Methane desorption characteristics of coal under definite water pressure comprises a complex two-phase flow process. A series of mercury intrusion porosimetry (MIP) and desorption experiments at different water injection pressures are reported in this study. Three lumpy coal samples were used in desorption experiments at three different water injection pressures and at natural desorption for comparison. Samples comprising two ranks of coal were used for MIP measurements including the distribution of porosity and pore sizes. The results of this study enable the establishment of a new model that encompasses a critical theoretical pore size that is most effective for water injection into coalbeds and that can be related to water injection pressure, the length of residual water, and gas adsorption capacity. Data show that the use of different water injection pressures leads to different gas desorption capacities as well as variable time effects and degree of gas desorption. Critical pore size is therefore proposed as a new parameter that can be employed to describe high pressure water effects in the context of gas desorption and can be calculated using pore size and the volume distribution law, as well as via the moisture ratio that remains after experiments and the permanent desorption percentage.

Analysis on Gas Drainage Based on High-Pressure Water Injection

2012 ◽  
Vol 524-527 ◽  
pp. 1147-1152
Author(s):  
Chao Zheng ◽  
Tian Hong Yang ◽  
Qing Lei Yu ◽  
Peng Hai Zhang
Keyword(s):  
High Pressure ◽  
Coal Seam ◽  
Water Injection ◽  
Mine Safety ◽  
Gas Drainage ◽  
Damage Area ◽  
Major Disaster ◽  
Before And After ◽  
Pressure Water ◽  
Injection Technology

Gas outburst has been a major disaster in high gas mine. Flow law of gas in coal seam was studied, and gas drainage measures were proposed were extraordinarily useful for mine safety and rational use of gas. Finite element numerical method was applied to study changing law of gas pressure before and after the high-pressure water injection and damage deformation of coal under high-pressure water based on fluid-solid coupling and gas-solid coupling and damage theory. This research shows that: (1) a damage area was generated in coal seam under high-pressure water injection. Range of the damage area increase rapidly at the start of water injection and gradually slow down with the passage of time, eventually be more stable. (2) The permeability of rock mass of coal under high-pressure water injection. (3) High-pressure water injection had significant effect on gas drainage in a certain area. It provided a theoretical basis for selecting reasonable design programs to product gas by high-pressure water injection technology.

Identification-Free Adaptive Separate Layer Water Injection Control Based on Expert Amendment

2010 ◽  
Vol 44-47 ◽  
pp. 1470-1475
Author(s):  
Feng Shan Wang ◽  
De Li Jia ◽  
Shu Jin Zhang ◽  
Chong Jiang Liu ◽  
De Kui Xu
Keyword(s):  
Adaptive Control ◽  
Control Strategy ◽  
Water Injection ◽  
Strong Nonlinearity ◽  
Separate Layer ◽  
Injection Control ◽  
System Output ◽  
Adaptive Control Strategy ◽  
Injection Effect ◽  
Injection Technology

An identification-free adaptive control strategy based on expert amendment is proposed in this paper to solve the problem that it is difficult to establish mathematical model of water injection regulating process due to large time delay, strong nonlinearity and time variation in the flow control of separate layer water injection technology. In this control strategy, according to the past and current process information of water injection, the system output and trend can be estimated based on expert rules to amend the output of the identification-free adaptive control. The simulation result shows that this control strategy has perfect control performance and strong adaptability and it provides a feasible means for improving water injection effect.

scholarly journals Automated technique for high-pressure water-based window cleaning and accompanying parametric study

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0242413
Author(s):  
Youngjoo Lee ◽  
Daesung Kwon ◽  
Changmin Park ◽  
Myoungjae Seo ◽  
TaeWon Seo
Keyword(s):  
High Pressure ◽  
Evaluation Method ◽  
Water Pressure ◽  
Reaction Force ◽  
Field Tests ◽  
Image Data ◽  
Spray Angle ◽  
Cleaning Performance ◽  
Pressure Water ◽  
Automated Technique

The maintenance of buildings has become an important issue with the construction of many high-rise buildings in recent years. However, the cleaning of the outer walls of buildings is performed in highly hazardous environments over long periods, and many accidents occur each year. Various robots are being studied and developed to reduce these incidents and to relieve workers from hazardous tasks. Herein, we propose a method of spraying high-pressure water using a pump and nozzle, which differs from conventional methods. The cleaning performance parameters, such as water pressure, spray angle, and spray distance, were optimized using the Taguchi method. Cleaning experiments were performed on window specimens that were contaminated artificially. The cleaning performance of the proposed method was evaluated using the image-evaluation method. The optimum condition was determined based on the results of a sensitive analysis performed on the image data. In addition, the reaction force due to high pressure and impact force on the specimens were investigated. These forces were not sufficient to affect the propeller thrust or cause damage to the building’s surface. We expect to perform field tests in the near future based on the output of this research.

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