The Analysis of the Pulverized Coal Deposition in the Pump Cylinder in Drainage and Mining of the Coal Bed Methane (CBM)

2013 ◽  
Vol 712-715 ◽  
pp. 1359-1362 ◽  
Author(s):  
Yan Ping Sun ◽  
Ning Zhao ◽  
Wen Tao Qu
Keyword(s):  
Particle Size ◽  
Coal Particle ◽  
Pulverized Coal ◽  
Coal Bed ◽  
Coal Bed Methane ◽  
Size Change ◽  
Lower Velocity ◽  
Pressure Drag ◽  
Coal Particles ◽  
Pump Cylinder

In drainage and mining of the coal bed methane(CBM),pump valve jams caused by the settlement of pulverized coal particles directly affect the normal production of the coal bed methane(CBM).From the study of the pulverized coal particle size,this paper summarizes the law of the pulverized coal particle size change in various stages of the coal bed methane(CBM) production well drainage and ming.By analyzing the pulverized coal particle velocity distribution along the pump cylinder,the viewpoint that the pulverized coal particle has a higher axial velocity in the central part of the settlement and has a lower velocity near the wall surface is put forward to.Based on the theory,the motion track equation of the pulverized coal particle can be got by calculation.Under the condition of considering buoyancy,fluid resistance and pressure drag,instant drop speed of the pulverized coal in water is calculated.

scholarly journals Effects of temperature gradient and particle size on self-ignition temperature of low-rank coal excavated from inner Mongolia, China

2019 ◽  
Vol 6 (9) ◽  
pp. 190374 ◽  
Author(s):  
Yongjun Wang ◽  
Xiaoming Zhang ◽  
Hemeng Zhang ◽  
Kyuro Sasaki
Keyword(s):  
Activation Energy ◽  
Particle Size ◽  
Temperature Gradient ◽  
Ignition Temperature ◽  
Coal Particle ◽  
Critical Value ◽  
Low Rank ◽  
Low Rank Coal ◽  
Coal Particles ◽  
Effects Of Temperature

This study investigates the effects of temperature gradient and coal particle size on the critical self-ignition temperature T CSIT of a coal pile packed with low-rank coal using the wire-mesh basket test to estimate T CSIT based on the Frank–Kamenetskii equation. The values of T CSIT , the temperature gradient and the apparent activation energy of different coal pile volumes packed with coal particles of different sizes are measured. The supercriticality or subcriticality of the coal is assessed using a non-dimensional index I HR based on the temperature gradient at the temperature cross-point between coal and ambient temperatures for coal piles with various volumes and particle sizes. The critical value I HRC at the boundary between supercriticality and subcriticality is determined as a function of pile volume. The coal status of supercritical or subcritical can be separated by critical value of I HR as a function of pile volume. Quantitative effects of coal particle size on T CSIT of coal piles are measured for constant pile volume. It can be concluded that a pile packed with smaller coal particles is more likely to undergo spontaneous combustion, while the chemical activation energy is not sensitive to coal particle size. Finally, the effect of coal particle size on T CSIT is represented by the inclusion of an extra term in the equation giving T CSIT for a coal pile.

Coal Particles Cleanout Technology in Coal Bed Methane Wells

2012 ◽  
Vol 229-231 ◽  
pp. 2470-2473 ◽  
Author(s):  
Bing Liu ◽  
Yao Guang Qi ◽  
Chao Wang ◽  
Chun Cheng Xu ◽  
Fen Na Zhang ◽  
...  
Keyword(s):  
High Efficiency ◽  
New Technology ◽  
Gas Production ◽  
Coal Bed ◽  
Working Fluid ◽  
Coal Bed Methane ◽  
Skin Damage ◽  
Technology System ◽  
Coal Particles ◽  
Continuous Vacuum

Coal particles cleanout which is regarded as the key technology in the operation of coal bed methane (CBM) wells, play an important part in making steady production. In oil wells, Sand cleanout is operated by circulating a liquid or a multiphase fluid into the wellbore to bring sand particles to the surface. Although the sand cleanout operations have been applied successfully in most wells with high efficiency and negligible leakage, it would leak working fluid into coal bed formation, destroy the structure of coal bed and jam the formed channel of gas production. In this paper, a new continuous vacuum cleanout technology has been developed to effectively remove coal particles in CBM wells by employing a jet pump. The Concentric Tubing String (CTS) which is assembled by 3.5 inch tubing and 1.5 inch tubing is also introduced in, because there is no CCT technology in China at the moment. Detailed structure and principle of the coal particles cleanout technology system are described, while a theoretical model is formulated to optimally design the system based on the coal particles settling experimental data and jet pumping theory. It has been shown from field applications that the coal particles cleanout technology makes significant improvements in achieving high efficiency and preventing leakage in CBM wells. Moreover, the new technology reduces the skin damage and increase the production compared to non-vacuum CBM wells.

The Molding Process for Synthesizing Formed Coke with Low Rank Pulverized Coal

2012 ◽  
Vol 512-515 ◽  
pp. 2043-2046 ◽  
Author(s):  
Qiu Li Zhang ◽  
Xuan Cheng ◽  
Xin Zhe Lan ◽  
Xi Cheng Zhao
Keyword(s):  
Particle Size ◽  
Moisture Content ◽  
Coal Particle ◽  
Pulverized Coal ◽  
Low Rank ◽  
Optimal Conditions ◽  
Molding Process ◽  
Fine Coal

The paper investigates the molding process of producing formed coke with low rank pulverized coal. When the bentonite as binder, the technological conditions mainly including bentonite content, forming pressure, forming moisture and particle size factors which effect on the strength of formed cokes were systematically discussed and obtained the optimal conditions. Under the conditions of amount of bentonite 5%, forming pressure 40kN, moisture content 14%, and fine coal particle size<5mm the formed coke with strength of 600N/ball was prepared and it satisfied the standard of gasification behavior of formed coke.

scholarly journals Numerical simulation study on the influence of pulverized coal particle size on boiler combustion characteristics

2020 ◽  
Vol 218 ◽  
pp. 01009
Author(s):  
Zhihai Cheng ◽  
Yang Li ◽  
Zhonghan Zhang
Keyword(s):  
Numerical Simulation ◽  
Particle Size ◽  
Combustion Zone ◽  
Coal Particle ◽  
Average Particle Size ◽  
Pulverized Coal ◽  
Average Particle ◽  
Temperature Level ◽  
Nox Formation ◽  
Average Temperature

The influence of pulverized coal particle size on combustion and NOx formation of 660MW tangential combustion ultra-supercritical boiler in a power plant was studied by using commercial software FLUENT. The average particle size of pulverized coal was set at 61μm, 71μm and 80μm, respectively. The results show that with the decrease of pulverized coal particle size, the overall temperature level of the boiler increases, the average temperature of the main combustion zone increases, the temperature of the upper part of the main combustion zone decreases, and the combustion of pulverized coal is more incomplete. However, the probability of particles sticking to the wall and the probability of coking and slagging of the boiler increases. The amount of NOx produced in the main combustion zone decreases, while the amount of NOx produced in the upper part of the main combustion zone increases, while the overall amount of NOx produced increases slightly.

scholarly journals Investigation of thermochemical process of coal particle packed bed reactions for the development of UCG

2020 ◽  
Author(s):  
Tata Sutardi ◽  
Linwei Wang ◽  
Nader Karimi ◽  
Manosh C Paul
Keyword(s):  
Particle Size ◽  
Coal Particle ◽  
Coal Gasification ◽  
Packed Bed ◽  
Packed Bed Reactor ◽  
Underground Coal Gasification ◽  
Heater Temperature ◽  
Gasification Process ◽  
Coal Particles ◽  
Thermochemical Processes

Abstract In this study, a packed bed reactor is developed to investigate the gasification process of coal particles. The effects of coal particle size and heater temperature of reactor are examined to identify the thermochemical processes through the packed bed. Three different coal samples with varying size, named as A, B, and C, are used, and the experimental results show that the packed bed with smaller coal size has higher temperature, reaching 624oC, 582oC, and 569oC for coal A, B, and C respectively. In the case of CO formation, the smaller particle size has greater products in the unit of mole fraction over the area of generation. However, the variation in the porosity of the packed bed due to different coal particle sizes affects the reactions through the oxygen access. Consequently, the CO formation is least from the coal packed bed formed by the smallest particle size A. A second test with the temperature variations shows that the higher heater temperature promotes the chemical reactions, resulting in the increased gas products. The findings indicate the important role of coal seam porosity in UCG (underground coal gasification) application, as well as temperature to promote the syngas productions.

Effects of pulverized coal particle size on flame structure in a methane-assisted swirl burner

Fuel ◽  
2019 ◽  
Vol 242 ◽  
pp. 68-76 ◽  
Author(s):  
Xinzhuo Li ◽  
Minsung Choi ◽  
Kibeom Kim ◽  
Yeseul Park ◽  
Yonmo Sung ◽  
...  
Keyword(s):  
Particle Size ◽  
Coal Particle ◽  
Flame Structure ◽  
Pulverized Coal ◽  
Swirl Burner

Structure Optimization and Strength Analysis of CBM Special Anti-Clogging Drainage Pump

2012 ◽  
Vol 479-481 ◽  
pp. 2017-2021
Author(s):  
Wen Tao Qu ◽  
Yi Xiao Guo ◽  
Tao Ren ◽  
Yan Ping Sun
Keyword(s):  
Solid Particles ◽  
Working Environment ◽  
Coal Bed ◽  
Coal Bed Methane ◽  
Strength Analysis ◽  
Element Analysis ◽  
Fine Coal ◽  
Coal Particles ◽  
Valve Housing ◽  
Production Areas

There are abundant coal bed methane resources in China, and recovery technology is considered a very important part in the development of coal bed methane. At present, coal bed methane production areas are still adopting the tubing liner pump, but because of the special working environment, in the pumping process, the fine breeze (sand) and other solid particles entering into the pump barrel is likely to cause the pump stuck, pipe string buried by sand and other issues. In view of the above problems, based on the ordinary tubing liner pump, through the increase of the anti-litter bypass style traveling valve housing and fixed valve housing, outside liner jacket, sand reservoir and liquid in tee joint measures we developed a new type of CBM special anti-clogging drainage pump and adopted finite element analysis software ANSYS to complete key parts of strength calculation. The use of this pump will effectively reduces the blocking of fine coal particles (sand) and other solid particles, decreases the pump's checking operation and workload of sand bailing, consequently improves efficiency, reduces overall operating costs.

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