Effects of dust controls on respirable coal mine dust composition and particle sizes:case studies on auxiliary scrubbers and canopy air curtain

Control of dust in underground coal mines is critical for mitigating both safety and health hazards.For decades,the National Institute of Occupational Safety and Health(NIOSH)has led research to evaluate the effectiveness of various dust control technologies in coal mines.Recent studies have included the evaluation of auxiliary scrubbers to reduce respirable dust downstream of active mining and the use of canopy air curtains(CACs)to reduce respirable dust in key operator positions.While detailed dust characterization was not a focus of such studies,this is a growing area of interest.Using preserved filter samples from three previous NIOSH studies,the current work aims to explore the effect of two different scrubbers(one wet and one dry)and a roof bolter CAC on respirable dust composition and particle size distribution.For this,the preserved filter samples were analyzed by thermogravimetric analysis and/or scanning electron microscopy with energy dispersive X-ray.Results indicate that dust composition was not appreciably affected by either scrubber or the CAC.However,the wet scrubber and CAC appeared to decrease the overall particle size distribution.Such an effect of the dry scrubber was not consistently observed,but this is probably related to the particular sampling location downstream of the scrubber which allowed for significant mixing of the scrubber exhaust and other return air.Aside from the insights gained with respect to the three specific dust control case studies revisited here,this work demonstrates the value of preserved dust samples for follow-up investigation more broadly.

Application of foam technology for dust control in underground coal mine

In order to effectively control the dust in the underground coal mine,this study proposes and develops a new technology for dust control by foam,and briefly demonstrates the advantage of the foam technology for dust control,such as the good isolation performance,large contact area,high wetting ability,strong adhesion and so on.Besides,the details of the technology are introduced,including the foam agent,foam generator,and foam production process.Then the paper studies the relationship between the foaming agent concentration and liquid surface tension,and explains the principle of the foam generator.The technology is applied in heading face.The application results show that the foam has a remarkable effect on dust control in underground coal mines.

A comparative study of dust control practices in Chinese and Australian longwall coal mines

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.

A new design of foam spray nozzle used for precise dust control in underground coal mines

In order to improve the utilization rate of foam,an arc jet nozzle was designed for precise dust control.Through theoretical analysis,the different demands of foam were compared amongst arc jets,flat jets and full cone jets when the dust source was covered identically by foam.It is proved that foam consumption was least when an arc jet was used.Foam production capability of an arc jet nozzle under different conditions was investigated through experiments.The results show that with the gas liquid ratio(GLR)increasing,the spray state of an arc jet nozzle presents successively water jet,foam jet and mist.Under a reasonable working condition range of foam production and a fixed GLR,foam production quantity increases at first,and then decreases with the increase of liquid supply quantity.When the inner diameter of the nozzle is 14 mm,the best GLR is 30 and the optimum liquid supply quantity is0.375 m^3/h.The results of field experiments show that the total dust and respirable dust suppression efficiency of arc jet nozzles is 85.8%and 82.6%respectively,which are 1.39 and 1.37 times higher than the full cone nozzles and 1.20 and 1.19 times higher than the fiat nozzles.

Investigations of the effects of two typical jet crushing methods on the atomization and dust reduction performance of nozzles

Single-fuid nozzles and dual-fuid nozzles are the two typical jet crushing methods used in spray dust reduction. To distinguish the atomization mechanism of single-fuid and dual-fuid nozzles and improve dust control efciency at the coal mining faces, the atomization characteristics and dust reduction performance of the two nozzles were quantitatively compared. Results of experiments show that, as water supply pressure increased, the atomization angle of the swirl pressure nozzle reaches a maximum of 62° at 6 MPa and then decreases, but its droplet size shows an opposite trend with a minimum of 41.7 μm. The water supply pressure helps to improve the droplet size and the atomization angle of the internal mixing air–liquid nozzle, while the air supply pressure has a suppressive efect for them. When the water supply pressure is 0.2 MPa and the air supply pressure reaches 0.4 MPa, the nozzle obtains the smallest droplet size which is 10% smaller than the swirl pressure nozzle. Combined with the dust reduction experimental results, when the water consumption at the working surface is not limited, using the swirl pressure nozzle will achieve a better dust reduction efect. However, the internal mixing air–liquid nozzle can achieve better and more economical dust reduction performance in working environments where water consumption is limited.

PARTICLE ELECTROSTATIC COAGULATION AND ITS APPLICATIONS IN DUST CONTROL

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%.

A Comparative Assessment of On-Site Application Effects of Mine Dust Prevention and Control Technology

Prolonged exposure to coal dust leads to various lung disorders, including incurable coal workers’ pneumoconiosis (CWP), and endangers miners’ health in underground mines. This article summarizes the latest research progress in dust control technology, including chemical dust suppressants, foam dust removal, ultrasonic atomization, magnetized water dust suppression, double curtains of wind and fog, biological nano-film, and emerging microbial dust suppressants in the field of dust. The actual application compares and analyzes the advantages and disadvantages of different dust removal technologies. The current three directions of mine dust prevention and control are pointed out: the prevention and control of respirable dust, hydrophobic dust, and secondary dust, and the prospects for future development trends. Given the treatment of respirable dust, it is necessary to strengthen the research on the dust generation mechanism under different working conditions and to explore the migration and settlement laws of respirable dust by constructing a numerical model of dust dynamics;for the treatment of hydrophobic dust, further research on the microphysical and chemical properties of coal dust is needed. The relationship between wettability and continuously optimizing the wetting agent;for the prevention and control of secondary dust in coal mines, emerging microbial dust suppression technologies need to be developed to explore the micro-action between microorganisms and coal dust molecules to achieve green prevention and control of dust.

半煤岩巷快速掘进工作面粉尘综合治理技术及装备研究

快速掘进工作面由于掘进速度快、产尘强度高导致粉尘污染严重,特别是岩巷以及半煤岩巷道,粉尘污染程度更高。以袁大滩煤矿半煤岩快速掘进工作面为研究对象,设计了新型的滚筒下部喷雾、大臂喷雾、滚筒底部喷雾、滚筒上部喷雾及转载喷雾,同时设计了配套机载控除尘系统。经过现场实测,采用综合降尘措施后,总粉尘和呼吸性粉尘降尘效率最高分别达到91.37%和85.49%以上,降尘效果显著。

车载式多功能公路吹扫降尘设备的研发与应用

传统的吸尘车借助负压形成真空,大气压强差把杂物反推进去,因此耗油量大,成本高,功能单一,长时间清扫路面灰尘比较多,进气管道容易堵塞。车载式公路吹扫降尘车是一种具有构造简单,清扫效果明显,适用范围广,作用面积大,动力充足,直接作用于路面杂物、积雪、浮雪的便捷式吹扫设备,实现了高效作业,节约了劳动消耗,并且燃油经济性较高,成为环兰高速公路路面日常保洁模式。

大型铸造工厂除尘系统设计与应用

钢铁制造业是消耗能源的大户,更是大气污染的重点行业。因此,控制工业粉尘对环境的污染破坏以及人身的健康危害是现阶段急需解决的问题。根据铸造工厂的车间实际情况,阐述除尘系统的最优设计方案以及智能控制的应用。

光伏组件表面积灰监控系统设计与实现

光伏组件表面积灰会影响组件的发电效率,降低光伏电站运行的经济性。为了能够监测光伏电站中组件表面的积灰状态,进而基于监测数据进行光伏电站清洗运维优化方法的研究,提出一种光伏电站组件表面积灰监控系统。该系统中,下位机采用STM32F407微处理器扩展ADS1256模数转换器采集与积灰相关的多种传感器信号,并通过无线传输模块将数据传给上位机监控软件。基于LabVIEW开发的上位机监控软件通过串口接收数据,处理并存储数据后,根据相应数据对光伏电站的清洗时间进行优化。经过实验测试,本系统能够准确地采集、传输、处理和储存数据,监测光伏电站组件表面的积灰状态并实现电站清洗时间的规划,对光伏电站清洗运维优化有重要意义。

电石储运系统的粉尘治理及回收利用创新技术

在电石储运系统中的卸车、破碎、储存及输送等工段,设备运行中会产生大量粉尘,影响环境安全、设备的使用寿命及操作人员的身体健康。通过采用区域封闭的卸车除尘系统、安全可靠的筒仓储存、封闭的破碎及输送设备、安全环保的粉尘回收系统,实现粉尘的有效治理及回收利用。

焦化企业粉尘来源与防治措施探讨

针对焦化企业因“以煤产焦”生产特性导致职工粉尘职业病危害的问题,通过分析焦炭生产过程中备煤阶段、炼焦阶段、干熄焦阶段的粉尘来源,介绍焦炭生产现场除尘治理地实践,以及防护用品发放及使用、粉尘危害防治与管理、防尘宣传和专题培训、职业健康监护与职业卫生档案管理4个方面的焦化企业粉尘防治管理实践进行探讨,通过以上方面在企业中的实践,使得焦化企业粉尘治理效果提高明显,为实现清洁生产,保护职工身体健康,为焦化企业的粉尘治理提供参考。

大断面综掘巷道机载除尘系统研究

山西省A煤矿通过在3307运输巷引进先进的MB670-Ⅰ型掘锚一体机+液压锚杆钻车实现了大断面巷道快速掘进,但是巷道掘进期间迎头高浓度粉尘成为制约巷道快速掘进的不利因素之一。结合3307运输巷现场条件、掘进设备生产工艺等对现有粉尘治理措施存在的问题进行了分析,并提出通过增设机载除尘系统实现粉尘高效治理。具体在MB670-Ⅰ型掘锚一体机上增设KCS-450D-Ⅰ型除尘器,在供风风筒靠近出风口增设附壁风筒,通过除尘器与附壁风筒相互配合将掘进迎头高浓度粉尘控制在迎头位置,减少粉尘外溢量,利用KCS-450D-Ⅰ型除尘器处理能力强、效率高等优势对迎头高浓度粉尘气流进行集中处理,降低巷道粉尘质量浓度。工程应用后,巷道掘进迎头呼吸性粉尘、全尘质量浓度最大分别为29.52、89.73 mg/m^(3),粉尘治理效果显著。

半煤岩综掘巷道综合防尘系统研究

山西省A煤矿3603工作面运输巷为半煤岩巷道。受截割断面大、速度快及截割煤岩含水率低等多因素影响,掘进迎头粉尘质量浓度较高,在一定程度制约了巷道快速掘进。为此,在分析运输巷掘进条件及产尘源的基础上,提出综合使用截割滚筒喷雾系统、机载控尘及除尘系统、风流净化装置进行粉尘治理,并对各降尘系统及装置布置情况进行详细分析。工程应用后,3603工作面运输巷综掘机司机位置全尘、呼吸性粉尘质量浓度分别降至55.99、31.32 mg/m^(3)以下,掘进迎头粉尘质量浓度高、环境恶劣问题得以显著改善,综合防尘系统应用效果显著。

快掘工作面粉尘治理技术研究与应用

为有效治理工作面粉尘,保证煤矿井下的安全高效生产,以孙家岔龙华煤矿20202回风巷快掘工作面为例,通过分析工作面的产尘特点及粉尘运移分布规律,再针对主要尘源点开展粉尘治理技术研究。结果表明,20202回风巷快掘工作面主要尘源为掘锚机滚筒连续高强度截割和垮落冲击产尘。快掘工作面粉尘随风流进入涡流区,使得高浓度粉尘主要集中于涡流区域内,粉尘浓度超过1000 mg/m^(3),但粉尘在后方扩散范围较小。进而提出了“抑尘、控尘、除尘”有机综合治理粉尘技术体系,研发了长度1.5 m、重量不超过5 kg、能够四周径向出风、前端轴向出风、轴径向调风简便的快接控风除尘装置,机载式负压除尘系统及配套工艺,形成配套的防尘工艺技术及装备。上述综合治理技术在工作面应用后,掘锚机平台工人操作地点降尘效率达88.1%;掘锚机后4~5 m处降尘效率达81.21%,有效实现了工作面的粉尘综合治理。

炼钢废气超低排改造实践

废气超低排改造是当前炼钢厂环保领域的重要课题,其实践应用对于提升环境质量、促进可持续发展具有深远意义。围绕废气超低排改造实践展开研究,通过深入探索改造技术、实施过程及效果评估等方面,结合具体案例,分析改造实践的成效与挑战,以期为废气超低排改造提供实践指导。

散料转运系统微雾抑尘技术的研究与开发

微雾抑尘技术被广泛应用于粉尘治理,但缺乏对其抑尘机理和设计方法的研究,导致微雾抑尘系统设计粗放、使用效果不佳。为了提升微雾抑尘系统的抑尘效率,分析了微雾抑尘技术的运行机理,提出了系统设计的核心要素及设计思想,并采用先进的计算机仿真技术CFD辅助系统设计,以提高微雾抑尘系统设计的准确性。

焦化厂皮带运输系统粉尘治理措施

为提高焦化厂皮带运输系统运输的稳定性,应做好粉尘治理工作。对焦化厂皮带运输系统粉尘的扩散过程与运动规律进行分析,并针对燃煤冲击、诱导风粉尘、设备故障等粉尘诱因进行探讨,提出相应的粉尘治理措施,期望可以有效控制粉尘的扩散,保障皮带运输系统的安全稳定性。

除尘风机变频控制在电铲正压净化系统中的应用

WK-35作业环境恶劣,传统的除尘装置经常堵塞或通风量不足,扬尘侵入机棚内,引起电器柜内元件发热,严重影响其寿命,导致电铲经常需要停机保养,大大降低了除尘系统的工作效率。针对该情况,设计了新的电铲机棚通风装置,通过增加通风量,满足机棚通风、除尘、降温等需求,并要求风机具有温控调节功能。针对该通风装置的电气需求设计了一种除尘风机变频控制方式,改造后WK-35电铲的通风、降温性能均能满足整套电铲正压净化系统的要求。