In order to obtain appropriate spray pressure and enhance the spraying and dust removal efficiency, various factors including the dust characteristics, nozzle spraying angle, effective spraying range, water consumptio...In order to obtain appropriate spray pressure and enhance the spraying and dust removal efficiency, various factors including the dust characteristics, nozzle spraying angle, effective spraying range, water consumption and droplet size are taken into account. The dust characteristics from different mines and atomization parameters of different pressure nozzles were measured. It was found that the internal pressure of coal cutters and roadheaders should be kept at 2 MPa, which could ensure large droplet size, large spraying angle and low water consumption and hence realizing a large-area covering and capture for large particle dusts. However, the external spray pressure should be kept at 4 MPa for smaller droplet size and longer effective spraying range, leading to effective dust removal in the operator zone. The spray pressure of support moving, drawing opening, and stage loader on a fully mechanized caving face and stage loader on a fully mechanized driving face should be kept at 8 MPa, under which the nozzles have long effective spraying range, high water flow and small droplet size for the rapid capture of instantaneous, high-concentration and small size dust groups. From the applications on the caving and driving faces in the coal mines, it is indicated that the optimization of spray pressure in different spraying positions could effectively enhance dust removal efficiency. Selecting appropriate nozzles according to the dust characteristics at different positions is also favorable for dust removal efficiency. With the selected nozzles under optimal pressures, the removal rates of both total dust and respirable dust could reach over70%, showing a significant de-dusting effect.展开更多
Fine particulates instead of others create particulate pollution and they are easier to escape from almost all conventional collectors of low- or medium-efficiency. It is of practical significance to take full advanta...Fine particulates instead of others create particulate pollution and they are easier to escape from almost all conventional collectors of low- or medium-efficiency. It is of practical significance to take full advantages of particle coagulation by electrostatic forces to upgrade the collertors' performance. This paper investigates the main mechanisms of coagulation, all possible electrostatic forces existing in the collectors and their effects on the particle coagulation. To make particle kinetic coagulation electrostatically enhanced be a step of the conventional collectors. operations,certain conditions should be created through some medifications of the collectors. Based on that ,the authors suggest that a precharger electro-cyclone technique be applied to improve the performance of common cyclones still widely used in many places. And a preliminary semi-industrial test has been carried out at Jiawang Power Station, Xuzhou, Jiangsu Province, and the results show that the modified cyclone increases its efficiency from about 80% to 92~94%.展开更多
Mine dust is one of the main hazards in underground longwall mines worldwide.In order to solve the mine dust problem,a significant number of studies have been carried out regarding longwall mine dust control,both in C...Mine dust is one of the main hazards in underground longwall mines worldwide.In order to solve the mine dust problem,a significant number of studies have been carried out regarding longwall mine dust control,both in China and Australia.This paper presents a comparative study of dust control practices in Chinese and Australian longwall mines,with particular references to statutory limits,dust monitoring methods and dust management practices,followed by a brief discussion on the research status of longwall mine dust control in both countries.The study shows that water infusion,face ventilation controls,water sprays,and deep and wet cutting in longwall shearer operations are commonly practiced in almost all underground longwall mines and that both Chinese and Australian longwall mine dust control practices have their own advantages and disadvantages.It is concluded that there is a need for further development and innovative design of more effective dust mitigation products or systems despite the development of various dust control technologies.Based on the examinations and discussions,the authors have made some recommendations for further research and development in dust control in longwall mines.It is hoped that this comparative study will provide beneficial guidance for scholars and engineers who are engaging in longwall mine dust control research and practice.展开更多
基金support from the National Natural Science Foundation of China (Nos.U1261205, 51474139 and 51204103)the Science and Technology Development Plan of Shandong Province (No.2013GSF12004)the Excellent Young Scientific Talents Project of Shandong University of Science and Technology (No.2014JQJH106)
文摘In order to obtain appropriate spray pressure and enhance the spraying and dust removal efficiency, various factors including the dust characteristics, nozzle spraying angle, effective spraying range, water consumption and droplet size are taken into account. The dust characteristics from different mines and atomization parameters of different pressure nozzles were measured. It was found that the internal pressure of coal cutters and roadheaders should be kept at 2 MPa, which could ensure large droplet size, large spraying angle and low water consumption and hence realizing a large-area covering and capture for large particle dusts. However, the external spray pressure should be kept at 4 MPa for smaller droplet size and longer effective spraying range, leading to effective dust removal in the operator zone. The spray pressure of support moving, drawing opening, and stage loader on a fully mechanized caving face and stage loader on a fully mechanized driving face should be kept at 8 MPa, under which the nozzles have long effective spraying range, high water flow and small droplet size for the rapid capture of instantaneous, high-concentration and small size dust groups. From the applications on the caving and driving faces in the coal mines, it is indicated that the optimization of spray pressure in different spraying positions could effectively enhance dust removal efficiency. Selecting appropriate nozzles according to the dust characteristics at different positions is also favorable for dust removal efficiency. With the selected nozzles under optimal pressures, the removal rates of both total dust and respirable dust could reach over70%, showing a significant de-dusting effect.
文摘Fine particulates instead of others create particulate pollution and they are easier to escape from almost all conventional collectors of low- or medium-efficiency. It is of practical significance to take full advantages of particle coagulation by electrostatic forces to upgrade the collertors' performance. This paper investigates the main mechanisms of coagulation, all possible electrostatic forces existing in the collectors and their effects on the particle coagulation. To make particle kinetic coagulation electrostatically enhanced be a step of the conventional collectors. operations,certain conditions should be created through some medifications of the collectors. Based on that ,the authors suggest that a precharger electro-cyclone technique be applied to improve the performance of common cyclones still widely used in many places. And a preliminary semi-industrial test has been carried out at Jiawang Power Station, Xuzhou, Jiangsu Province, and the results show that the modified cyclone increases its efficiency from about 80% to 92~94%.
基金supported by the Program for New Century Excellent Talents in University of China(No.NCET-10-0770)the financial support provided by the China Scholarship Council(Nos.201306425002&201406425048)the University of Wollongong to pursue study at the University of Wollongong as undergraduate visiting students
文摘Mine dust is one of the main hazards in underground longwall mines worldwide.In order to solve the mine dust problem,a significant number of studies have been carried out regarding longwall mine dust control,both in China and Australia.This paper presents a comparative study of dust control practices in Chinese and Australian longwall mines,with particular references to statutory limits,dust monitoring methods and dust management practices,followed by a brief discussion on the research status of longwall mine dust control in both countries.The study shows that water infusion,face ventilation controls,water sprays,and deep and wet cutting in longwall shearer operations are commonly practiced in almost all underground longwall mines and that both Chinese and Australian longwall mine dust control practices have their own advantages and disadvantages.It is concluded that there is a need for further development and innovative design of more effective dust mitigation products or systems despite the development of various dust control technologies.Based on the examinations and discussions,the authors have made some recommendations for further research and development in dust control in longwall mines.It is hoped that this comparative study will provide beneficial guidance for scholars and engineers who are engaging in longwall mine dust control research and practice.
