(1) Pre-wet coal injection layer technology. Coal seam water injection is an effective preventive dust reduction measure in coal mining. As early as the 1940s, foreign countries have begun to use this method to reduce dust. So far, it has become the main coal mining in the United States, Britain, Germany, Russia, Belgium and Poland. Dust reduction measures widely used in the country. China first tested the coal body pre-injection water dust-proof technology in Benxi Caiyu Coal Mine in 1956. By 1990, 40% of the coal mining face had implemented coal body pre-injection water dust-proof technology. After years of scientific research practice, coal seam water pre-wetting coal has become the core of China's comprehensive dust prevention technology. It has developed a complete set of technology for coal seam water injection such as long borehole, short borehole and deep borehole, and developed a cement mortar sealer pump to solve the problem. The problem of difficult sealing is to improve the effect of water injection and dust reduction in coal seams. An automated controlled water injection system was developed.
With the promotion and application of fully mechanized top coal caving technology in China, the mining thickness of fully mechanized caving mining is mostly above 5m, and the maximum thickness has reached 10m. However, the permeability of general coal seam in the direction perpendicular to the roof is poor. The water injection process can not meet the needs of thick coal seam mining. During the “Ninth Five-Year Plan†period, Yankuang Group Co., Ltd. and the Chongqing Branch of the Coal Science Research Institute jointly tackled the research and development of coal seam water injection technology suitable for thick coal seam mining.
During the “Ninth Five-Year Plan†period, the Coal Research Institute and Yankuang Group Co., Ltd. developed a fully automatic water injection system consisting of flow and pressure sensors, proportional control valves, computers, pumps and hydraulic systems. The automatic control system and equipment for coal seam water injection is a typical electromechanical and hydraulic integrated equipment. In order to ensure the reliable operation of the system, each subsystem has manual and automatic control functions.
(2) Dust control technology of shearer. Since the "Eighth Five-Year Plan", the research on the efficient treatment technology of shearer, hydraulic support and coal 1:3 dust has been carried out, and the dust control of the coal mining machine and the high-pressure water spray dust reduction technology have been studied. The hydraulic support and coal injection port implement automatic control of water spray dust reduction technology, so that the dust concentration in the air of the driver of the shearer is reduced by 60%~70% and 82 respectively after using the dusty airflow control technology and the high pressure external spray dust reduction technology. %～93%, the use of hydraulic support and coal injection El automatic spray dust reduction technology reduced the total dust concentration and respirable dust concentration of the coal handling machine operation by 84.7% and 67.5% respectively, so that the lower wind flow was 7m when the bracket was moved. The total dust concentration and the respirable dust concentration decreased by 74.6% and 61.1%, respectively, which better reduced the dust concentration of the dusty airflow. The crusher sonic atomization dust reduction technology, magnetized water dust reduction technology, pre-charged spray dust reduction technology and high-pressure spray dust reduction technology were studied at the crusher. The dust reduction efficiency of total dust and respiratory dust was as high as 85%~97.7% and 87.1 respectively. % ~ 97.9%, greatly reducing the dust pollution of the air when the crusher works.
2. Dust removal technology for comprehensive excavation face
With the improvement of the level of comprehensive excavation and the development of dust-proof technology, the focus of dust control is to transfer the total dust to the control of respirable dust. Some dust control technologies and equipment have been successfully studied.
On the basis of the problem of high-concentration dust in the face of the excavation face with the wet dust collector studied during the "Seventh Five-Year Plan" period, during the "Eighth Five-Year Plan" period, the bag filter for coal mines and its special KDZ counter-rotation were developed. Axial fan. The dust collector has a treatment air volume of 230-250 m3/min, a working resistance of 2000 Pa (near the wet filter type dust collector), and a motor power of 2×26 kW. The dust removal efficiency of the total dust and the respirable dust is as high as 99% and 90%, respectively. After the wall air duct is used on the surface of the excavation with a sectional area of ​​10 m2 or more, the total dust concentration and the respirable dust concentration of the driver are reduced to 21.4 mg/m3 and 9.7 mg/m3, respectively, and the dust reduction efficiency is 93.27% and 90.53%, respectively. . At the same time, in order to solve the dust control of small section roadway excavation, a wet surface XZC rotary grid dust collector with a small air volume (90-130 m3/min) was developed, which has the dust removal efficiency of total dust and respirable dust. They reached 99% and 88.5% respectively. The successful research on the dry dust removal technology of the machine face marks a new step in the dustproof level of the machine drilling in China.
During the "Ninth Five-Year Plan" period, in order to reduce the volume of the bag filter, the research and extensive promotion of dry dust removal technology was carried out in a targeted manner, and the research reached: MTll3—1995 “Fire-retardant antistatic property of polymer products in underground coal mines†The mine safety and high efficiency dust removal filter material with high dust collection efficiency under the condition of high filtration wind speed (3.5-4.0m/min) is filled with the antistatic and flame retardant performance requirements specified in the General Test Methods and Decision Rules. China's filter material has a large gap in the coal industry, and its technical performance has reached the advanced level of similar foreign technology; due to the increase of filter material filtration speed, under the same treatment air volume (230 ~ 250m3 / min), the bag filter The volume has been reduced by 41% on the basis of the "Eighth Five-Year Plan". The dust volume of the dust collector is 224m3/min, the working resistance is 2083Pa, and the dust removal efficiency of total dust and respirable dust is 99.3% and 95.5%, respectively. In the industrial test of coal mine underground, 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 comprehensive Dust concentration of the face. The successful research of the dust filter material and the new bag filter has played a significant role in promoting the promotion and application of dry dust removal technology in China's coal mines, and is of great significance for improving the dust control technology level of coal mines in China.
Because the wet dust removal technology has the advantages of less investment and smaller volume than the dry dust removal technology, the dry dust removal technology is improved and improved in view of the small coal mine roadway and the economic benefits are generally not good. At the same time, in cooperation with the KOMAG Mining Mechanization Center in Poland, the research on high-efficiency wet dust removal technology suitable for the technical conditions of coal mine face production in China was carried out. The technology includes high-efficiency eddy current dust control devices, high-efficiency cyclone dust collectors and their associated mobile systems. The high-efficiency eddy current dust control device is about 7 times stronger than the original wall-attached air cylinder, and the dust control effect is better; the high-efficiency cyclone dust collector has a treatment air volume of 250-350 m3/min and a working resistance of 1800 Pa. The principle of multiple dust collectors is integrated. The dust removal efficiency of total dust and respirable dust is 99% and 94%-98% respectively. The technical performance is close to the level of bag filter, and the dewatering effect is very satisfactory. Its research success has brought China's coal mining machine wet dust removal technology to a new level.
3. Dust sampler
Since the 1990s, successful AIN-95 dust particle size distribution and concentration tester and AZF-01 respiratory breath sampler have been studied.
The ALN-95 dust particle size and concentration analyzer integrates the dust particle size distribution and concentration measurement. It uses the principle of light absorption to determine the dust concentration. The Stokes law is combined with the principle of light absorption to measure the dust particle size distribution. Data storage for dust concentration and particle size distribution measurements is automated. The sampling flow rate of the analyzer is 15L/min, the particle size distribution measurement range is 1~1501~m, and the concentration measurement range is not limited. It has been promoted and used in some coal mines in China.
In order to accurately determine the concentration of respirable dust in dusty air to evaluate the degree of environmental pollution caused by respirable dust, AZF-01 respiratory respirometer was successfully developed, which is a long-period respiratory dust sampler. After 8 hours of continuous operation, the measurement range of respiratory dust concentration is 1-300mg/m. The sampling flow rate is 3-4L/min, the load resistance is greater than 1000Pa, the sampling accuracy is ±10%, and the separation efficiency is in accordance with the BMRC international standard curve (the tolerance of each control point is ±5%). The pumping system of the double membrane pump and the steady flow device has the characteristics of stable sampling flow and large load capacity, and the rotary compact structure and the horizontally arranged sampling filter head solve the problem that the high concentration and long time collecting dust are easy to fall off. problem. Its research success has filled the blank of China's portable intrinsically safe, long-period fixed-point respiratory dust sampler, and its main technical performance is at the domestic leading level.
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