In light of the possibility of reignition when unsealing the closed fire zones, the occurrence of reignition was simulated by a home-made experimental device, hydrogen variety rule from combustion to unsealing was ana...In light of the possibility of reignition when unsealing the closed fire zones, the occurrence of reignition was simulated by a home-made experimental device, hydrogen variety rule from combustion to unsealing was analyzed, the three-stage generation model of hydrogen during reignition in fire zone was put forward and the probability that hydrogen was taken as an indicator gas was discussed. The results show that: when fire zone is ready to unseal, which is filled with hydrogen at a high concentration, it is more prone to reignite.展开更多
Based on mine fire fighting practices at the 1110 working face of the Brapukuria Coal Mine,Bangladesh,we introduce and discuss the Y-Inversion Ventilation System,the latest technology used both in mine fire zone manag...Based on mine fire fighting practices at the 1110 working face of the Brapukuria Coal Mine,Bangladesh,we introduce and discuss the Y-Inversion Ventilation System,the latest technology used both in mine fire zone management and the unsealing process.This ventilation system can ensure that all miners breathed fresh air,providing protection for them during fire fighting and unsealing the fire zone.On the other hand,adjusting the amount of air at the working face and forming a CO leakage path controlled the state of the fire and as well ensured that the different fire extinguishing measures could be applied successfully.These are all fundamental techniques which ensured successful fire extinguishing and unsealing of the fire zone.We also analyzed the main reasons for the spontaneous coal combustion that occurred at the 1110 working face.Successful application of advanced composite polymer colloidal perfusion techniques,polymer foam MEA perfusion and fire-prevention technology by infusing nitrogen,used in mine fire zone management and unsealing,are presented.We value the experience with these techniques very highly and are of the opinion that these techniques could be widely used in mine fire fighting practices under similar spontaneous coal combustion conditions elsewhere.展开更多
In order to avoid serious safety accidents caused by closed fire zone,based on the continuous monitoring of atmospheric pressure at different monitoring points in multiple mines,the atmospheric pressure fluctuation mo...In order to avoid serious safety accidents caused by closed fire zone,based on the continuous monitoring of atmospheric pressure at different monitoring points in multiple mines,the atmospheric pressure fluctuation model and the air leakage model were established and analyzed.The change law with time of oxygen concentration and gas concentration in the fire zone were obtained due to atmospheric disturbances under the influence of different pressure difference,volume and size of fire area,wind resistance,gas emission,sealing moments,etc.so as to evaluate the explosion risk of a closed fire zone.Research showed that the mine atmosphere fluctuates with the atmosphere of ground,and the pressure difference between the inner and outer sides of the enclosed fire zone is affected by the periodic fluctuation of atmosphere,which has about 16-h cosine fluctuation and approximate 8-h fixed value.Compared with the fire zone with poor sealing quality,good sealing fire zone has better resistance to atmospheric disturbance.The reduction of oxygen concentration in the inner side of a well-sealed fire zone mainly depends on the dilution of methane,which is more likely to accumulate and rise rapidly.And the fire zone with poor sealing quality is easy to be interfered.The inner oxygen concentration and gas concentration are easily affected by the absolute gas emission and the air leakage in the fire zone.Fire zone with small wind resistance and small volume is especially obvious.At the initial stage of the closed fire zone it's very possible to happen explosion.The time duration of explosion danger varies under different conditions,and the atmospheric disturbance may lead to repeated explosions in some cases.It's suggested to take some methods to avoid explosions according to the real-time situation,closure time,oxygen concentration and gas concentration of fire zone.展开更多
To apply the fire modelling for the fire engineer with symbolic mathematics,the key equations of a zone model were demonstrated. There were thirteen variables with nine constraints,so only four ordinary differential e...To apply the fire modelling for the fire engineer with symbolic mathematics,the key equations of a zone model were demonstrated. There were thirteen variables with nine constraints,so only four ordinary differential equations (ODEs) were required to solve. A typical fire modelling with two-room structure was studied. Accordingly,the source terms included in the ODEs were simplified and modelled,and the fourth Runge-Kutta method was used to solve the ordinary differential equations (ODEs) with symbolic mathematics. Then a zone model could be used with symbolic mathematics. It is proposed that symbolic mathematics is possible for use by fire engineer.展开更多
基金supported by the National Natural Science Foundation of China (No.50604014)the Program for New Century Excellent Talent Project(No.NCET-08-0838)the Research Fund of the State Key Laboratory of Coal Resources and Safe Mining,CUMT (No.09KF11)
文摘In light of the possibility of reignition when unsealing the closed fire zones, the occurrence of reignition was simulated by a home-made experimental device, hydrogen variety rule from combustion to unsealing was analyzed, the three-stage generation model of hydrogen during reignition in fire zone was put forward and the probability that hydrogen was taken as an indicator gas was discussed. The results show that: when fire zone is ready to unseal, which is filled with hydrogen at a high concentration, it is more prone to reignite.
基金supported by the Key Laboratory Opening Fund of Coalmine Gas & Fire Protection of Henan Province (No.HKLGF200702)
文摘Based on mine fire fighting practices at the 1110 working face of the Brapukuria Coal Mine,Bangladesh,we introduce and discuss the Y-Inversion Ventilation System,the latest technology used both in mine fire zone management and the unsealing process.This ventilation system can ensure that all miners breathed fresh air,providing protection for them during fire fighting and unsealing the fire zone.On the other hand,adjusting the amount of air at the working face and forming a CO leakage path controlled the state of the fire and as well ensured that the different fire extinguishing measures could be applied successfully.These are all fundamental techniques which ensured successful fire extinguishing and unsealing of the fire zone.We also analyzed the main reasons for the spontaneous coal combustion that occurred at the 1110 working face.Successful application of advanced composite polymer colloidal perfusion techniques,polymer foam MEA perfusion and fire-prevention technology by infusing nitrogen,used in mine fire zone management and unsealing,are presented.We value the experience with these techniques very highly and are of the opinion that these techniques could be widely used in mine fire fighting practices under similar spontaneous coal combustion conditions elsewhere.
基金the National Natural Science Foundation of China(No.51804054)Natural Science Foundation of Chongqing(CN)(No.cstc2019jcyj-msxmX0324)+2 种基金project of science and technology research program of Chongqing Education Commission of China(No.KJQN201801517)Research Fund of Chongqing University of Science&Technology(No.ck2017zkyb001)Open Cooperative Innovation Fund of Xi'an Institute of Modern Chemistry(No.204-J-2019-0387).Thanks.
文摘In order to avoid serious safety accidents caused by closed fire zone,based on the continuous monitoring of atmospheric pressure at different monitoring points in multiple mines,the atmospheric pressure fluctuation model and the air leakage model were established and analyzed.The change law with time of oxygen concentration and gas concentration in the fire zone were obtained due to atmospheric disturbances under the influence of different pressure difference,volume and size of fire area,wind resistance,gas emission,sealing moments,etc.so as to evaluate the explosion risk of a closed fire zone.Research showed that the mine atmosphere fluctuates with the atmosphere of ground,and the pressure difference between the inner and outer sides of the enclosed fire zone is affected by the periodic fluctuation of atmosphere,which has about 16-h cosine fluctuation and approximate 8-h fixed value.Compared with the fire zone with poor sealing quality,good sealing fire zone has better resistance to atmospheric disturbance.The reduction of oxygen concentration in the inner side of a well-sealed fire zone mainly depends on the dilution of methane,which is more likely to accumulate and rise rapidly.And the fire zone with poor sealing quality is easy to be interfered.The inner oxygen concentration and gas concentration are easily affected by the absolute gas emission and the air leakage in the fire zone.Fire zone with small wind resistance and small volume is especially obvious.At the initial stage of the closed fire zone it's very possible to happen explosion.The time duration of explosion danger varies under different conditions,and the atmospheric disturbance may lead to repeated explosions in some cases.It's suggested to take some methods to avoid explosions according to the real-time situation,closure time,oxygen concentration and gas concentration of fire zone.
基金Project(PolyU B-Q01e) supported by the Research Project "Onsetting of Internal Fire Whirls in Buildings and Associated Safet Provision"
文摘To apply the fire modelling for the fire engineer with symbolic mathematics,the key equations of a zone model were demonstrated. There were thirteen variables with nine constraints,so only four ordinary differential equations (ODEs) were required to solve. A typical fire modelling with two-room structure was studied. Accordingly,the source terms included in the ODEs were simplified and modelled,and the fourth Runge-Kutta method was used to solve the ordinary differential equations (ODEs) with symbolic mathematics. Then a zone model could be used with symbolic mathematics. It is proposed that symbolic mathematics is possible for use by fire engineer.
