Dust control technology in the hottest coal mine

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Coal mine dust prevention and control technology

with the rapid development of fully mechanized mining and fully mechanized excavation technology, especially the wide application of high-yield and high-efficiency working faces and fully mechanized top coal caving working faces, the problem of coal mine dust pollution in China is becoming more and more serious. After the scientific and technological breakthrough during the eighth five year and Ninth Five Year Plan period, the dust prevention and reduction technology has made great progress, in coal seam water injection, coal miner dust prevention, hydraulic support dust prevention, coal caving mouth dust prevention and fully mechanized excavation flour dust efficient control Breakthrough progress has been made in the research, popularization and application of respirable dust testing instruments with two loops of position control and force control

1. Dust prevention technology of fully mechanized mining face

(1) coal seam pre wetting water injection technology. Coal seam water injection is an effective preventive dust reduction measure in coal mining. As early as the 1940s, this method has been used abroad to reduce dust, and has become a widely used dust reduction measure in major coal mining countries such as the United States, Britain, Germany, Russia, Belgium and Poland. From 1956, China first tested the coal pre injection dust prevention technology in Benxi caitun coal mine, to 1990, 40% of the coal faces have implemented the coal pre injection dust prevention technology. After years of scientific research and practice, the pre wetting of coal body by coal seam water injection has become the core of China's comprehensive dust prevention technology. A complete set of technologies for coal seam water injection such as long drilling, short drilling and deep drilling have been developed, and a cement mortar hole sealing pump has been developed, which solves the problem of difficult hole sealing and improves the effect of coal seam water injection and dust reduction. An automatic water injection system is developed

with the popularization and application of fully mechanized top coal caving technology in China, but because the mining thickness of fully mechanized top coal caving mining is mostly more than 5m, and the maximum thickness has reached 10m, and the permeability of general coal seams in the direction perpendicular to the roof is poor, the traditional water injection technology can not meet the needs of thick coal seam mining. During the Ninth Five Year Plan period, Yankuang Group Co., Ltd. and Chongqing Branch of General Academy of Coal Sciences jointly addressed key problems, Research and develop coal seam water injection technology suitable for thick coal seam mining

during the Ninth Five Year Plan period, the general Coal Research Institute and Yankuang Group Co., Ltd. developed a fully automatic water injection system composed of flow and pressure sensors, proportional control valves, computers, pumps, and hydraulic systems. Coal seam water injection automatic control system and equipment are typical electromechanical hydraulic integration equipment. In order to ensure that the system can work reliably, all subsystems have manual and automatic control functions

(2) dust prevention technology of shearer. Since the eighth five year plan, the research on the efficient treatment technology of 1:3 dust of shearer, hydraulic support and coal caving has been carried out. The dust laden air flow control of shearer and high-pressure water spray dust reduction technology have been studied successively, and the automatic control water spray dust reduction technology has been implemented for hydraulic support and coal caving mouth, The dust concentration in the air at the driver's place of the shearer has decreased by 60% - 70% and 82% - 93% respectively after the use of dust containing air flow control technology and high-pressure external spray dust reduction technology. The use of hydraulic support and coal caving El automatic spray dust reduction technology has reduced the total dust concentration and respiratory dust concentration at the operation place of coal caving workers by 84.7% and 67.5% respectively, The total dust concentration and respirable dust concentration at 7m of the lower air flow when the support is moved are reduced by 74.6% and 61.1% respectively, which better reduces the dust concentration of the dusty air flow. At the crusher, sound wave atomization dust reduction technology, magnetized water dust reduction technology, pre charged spray dust reduction technology and high-pressure spray dust reduction technology have been developed. The dust reduction efficiency of total dust and respiratory dust is as high as 85% - 97.7% and 87.1% - 97.9% respectively, which greatly reduces the dust pollution of the air when the crusher is working

2. Dust removal technology in fully mechanized mining face

with the improvement of fully mechanized mining level and the development of excavation dust prevention technology, the focus of dust control has shifted from the control of total dust to the control of respiratory dust, and some dust control technologies and equipment have been successfully studied

on the basis of solving the problem of high concentration dust in machine excavation face with wall attached air duct and wet dust collector studied during the Seventh Five Year Plan period, bag type dust collector for coal mine and its special KDZ counter rotating axial flow fan were developed during the Eighth Five Year Plan period. The dust collector has a processing air volume of 230 ~ 250m3/min, a working resistance of 2000Pa (close to the wet filter dust collector), and a motor power of 226kw. The dust removal efficiency for total dust and respiratory dust is as high as 99% and 90% respectively. After being used with the wall attached air duct on the machine excavation surface with a sectional area of more than 10m2, the total dust concentration and respiratory dust concentration at the driver are reduced to 21.4mg/m3 and 9.7mg/m3 respectively, The dust reduction efficiency is 93.27% and 90.53% respectively. At the same time, in order to solve the dust control of small cross-section roadway excavation, a wet XZC rotary grid dust collector with small air volume (90130m3/min) is developed. Its dust removal efficiency for total dust and respiratory dust reaches 99% and 88.5% respectively. The success of the research on the dry dust removal technology of the machine excavation face marks a new step in the dust prevention level of the machine excavation in our country

during the Ninth Five Year Plan period, in order to reduce the volume of bag filter, targeted research and extensive promotion of dry dust removal technology were carried out, and the research reached the requirements of antistatic and flame retardant properties specified in mtll3 1995 general test methods and judgment rules for flame retardant and antistatic properties of polymer products in underground coal mines, In addition, under the condition of high filtration wind speed (3.54.0m/min), mining with high dust collection efficiency is safe and efficient. In addition, China's biological resources, energy and machinery industry is facing greater market opportunities in the future. The dust filter material fills a big gap in China's filter material in the coal industry, and its technical performance has reached the advanced level of similar foreign technologies; Due to the increase of filter material filtration wind speed, under the same treatment air volume (230 ~ 250m3/min), the volume of bag filter is reduced by 41% on the basis of the eighth five year plan. The treatment air volume of the dust collector is 224m3/min, the working resistance is 2083pa, and the dust removal efficiency of total dust and respiratory dust reaches 99.3% and 95.5% respectively. During the industrial test in the coal mine, the total dust concentration and respiratory dust concentration at the driver of the roadheader decreased to 18.38mg/m3 and 8.89mg/m3 respectively, and the dust removal efficiency reached 91.1% and 92.25% respectively, effectively reducing the dust concentration in the fully mechanized face. The successful research of the dust removal filter material and the new bag type dust collector has played a significant role in promoting the popularization and application of dry dust removal technology in coal mines in China, and is of great significance in improving the dust prevention technology level of coal mining machinery in China

compared with dry dust removal technology, wet dust removal technology has the advantages of less investment and smaller volume. Therefore, in view of the characteristics of China's coal mine machine driven roadways 1. The multi-stage pressure maintaining test can be set, which is small, and the economic benefits are generally not very good, while improving the dry dust removal technology, it also cooperates with Poland's komag mining mechanization center, The research on high-efficiency wet dust removal technology suitable for the production technical conditions of coal mining machine face in China has been carried out. The technology includes high-efficiency vortex dust control device, high-efficiency cyclone dust collector and its supporting mobile system. The high-efficiency vortex dust control device is about 7 times stronger than the original wall attached air duct, and the dust control effect is better; The high-efficiency cyclone dust collector has a processing air volume of 250 ~ 350m3/min and a working resistance of 1800pa. It integrates the principles of various dust collectors, and its dust removal efficiency for total dust and respiratory dust reaches 99% and 94% - 98% respectively. Its technical performance is close to the level of bag dust collector, and its dehydration effect is very ideal. The success of its research has raised the level of wet dedusting technology of coal mining machinery in China to a new level

3. dust sampler

since the 1990s, ain-95 dust particle size distribution and concentration tester and azf-01 respirable dust sampler have been successfully studied

aln-95 dust particle size and concentration tester integrates dust particle size distribution and concentration measurement. It uses the principle of light absorption to measure dust concentration; Using Stokes' law and light absorption principle to measure the particle size distribution of dust, the data storage of dust sampling, dust concentration and particle size distribution measurement has been automated. The sampling flow of the tester is 15L/min, the particle size distribution measurement range is 1 ~ 1501~m, and the concentration measurement range is unlimited. At present, it has been popularized and used in some coal mines in China

in order to accurately measure the concentration of respirable dust in dusty air and evaluate the degree of environmental pollution caused by respirable dust, azf-01 respirable dust sampler is successfully developed. It is a long-period respirable dust sampler, which can work continuously for 8 hours, and its measurement range of respirable dust concentration is 1300 mg/m., The sampling flow is 34L/min, the load resistance is greater than 1000Pa, the sampling accuracy is 10%, and the separation efficiency is in line with the standard curve of body temperature testing instruments collected by BMRC international through CDC 1 (the allowable deviation of each control point is 5%). The air extraction system of the instrument with double membrane pump and steady flow device has the characteristics of stable sampling flow and large load capacity. Its rotary pressing structure and horizontally arranged sampling filter head solve the problem of high concentration and easy falling off of dust collected for a long time. Its successful research fills the gap of portable intrinsically safe and long-period fixed-point respirable dust sampler in China, and its main technical performance is at the domestic leading level

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