Foaming agent self-suction properties of a jet-type foam preparation device used in mine dust suppression

In this study, we introduce a jet-type foam preparation device for use in mine dust control, which can enhance the reliability and applicability of the foam production process compared with conventional foam generators. In order to elucidate the foaming agent self-suction properties of this novel foam generator, we used a self-built experimental setup to investigate the effects of the working pressure and outlet pressure on negative pressure (vacuum degree) during foaming agent suction, as well as the functional relationship between negative pressure and the foaming agent by adding parameters. We also studied the effects of the valve opening degree on the foaming agent flow rate and addition ratio. The results showed that the working pressure and outlet pressure affected the formation of negative pressure in a positive linear manner and a negative linear manner, respectively. Thus, the negative pressure increased linearly as the working pressure increased, whereas it decreased in a linear manner as the outlet pressure increased. There was also a quadratic relationship between the vacuum degree and foaming agent quantity with the piecewise characteristics of the growth process, where they increased slowly with a lower vacuum degree but increased rapidly with a higher vacuum degree. After creating a moderate negative pressure with the water jet, the foaming agent could be added automatically at a low flow rate with a low ratio via the regulating valve on the liquid suction hose. This study provides basic information that should facilitate the application of this novel foam preparation technique.     

Experimental investigation of the pressure gradient of a new spiral mesh foam generator

Foam is used as part of an effective dust suppression method in underground coal mines, but conventional foaming devices severely restrict its popularization and application due to the high cost of foam preparation, poor applicability and high pressure loss. Therefore, a new spiral mesh foam generator is designed, and its performance is investigated and evaluated experimentally. The results show that the pressure gradient of the spiral mesh foam generator increases with the increase of foam concentration in water. There is a large pressure gradient gap between the top and bottom at both ends of the foam generator. However, the gap disappears and uniform foam is generated in the middle section of the foam generator. When the pressure gradient is higher than minimum pressure gradient, the foam production quantity will increase sharply. Based on the length of spiral mesh and operating conditions determined, the new foam generator is applied to produce foam for dust suppression in the heading face of coal mines. A good foaming effect, less pressure loss and high dust suppression efficiency suggest that the new foam generator will greatly promote the large-scale application of foam technology used to suppress dust in underground coal mines.     

煤矿综掘面泡沫降尘技术研究与实施

针对煤矿综掘面粉尘治理技术中存在的不足,采用泡沫降尘新技术结合长压短抽式通风方式进行粉尘防治。以霍尔辛赫矿为例,根据井下实际情况,利用GAMB IT和FLUENT建立掘进巷道的几何模型,并对巷道掘进通风过程中粉尘分布规律进行解算,将模拟结果和现场实测数据对比,确定掘进面回风侧的高浓度粉尘分布区。对掘进面煤样进行湿润性试验,确定最佳的发泡剂添加比例。综合以上情况,泡沫降尘技术实施时采用环形前置式喷头布置,发泡剂添加比例定为10‰,并在回风侧距掘进面5 m、距底板2 m处设置风筒,将高浓度粉尘抽出并沉降。现场实测数据显示,泡沫降尘技术降尘效率明显高于喷雾降尘技术。使用泡沫降尘时,在司机侧测得全尘及呼吸性粉尘降尘效率分别达到75.4%和74.7%。     

露天矿山运输路面泡沫抑尘剂的配方优选及性能试验研究*

为有效解决露天矿山运输路面的大量扬尘,针对现有抑尘剂存在的降解性差、成本较高、保水率差、除尘效率过低等问题,在对某露天矿山的扬尘进行表征分析的基础上,采用绿色表面活性剂烷基糖苷0.1%APG作为主剂、0.6%K12作为起泡剂、0.4%PAM作为稳泡剂、0.3%LAS作为润湿剂,通过测定泡沫的表面张力、泡沫体积、粉尘接触角、粉尘浸润深度确定各试剂的最佳质量分数,初步确定6个泡沫抑尘剂配方,选择保水率、抗风蚀性、抑尘效率作为性能指标,结果表明:配方为m(0.6%K12)∶m(0.1%APG)∶m(0.4%PAM)∶m(0.3%LAS)=1.05∶1∶0.6∶0.1的保水性、抗压强度、抗风蚀性均优于其他配方,全尘与呼吸性粉尘的抑尘效率分别高达87.11%,75.26%,经pH测试,符合绿色环保的要求。     

水泥灰三相泡沫的形成机理与稳定性试验研究

针对高硫矿石容易发生氧化自燃的危险,通常的灌浆、注砂、注惰气和喷洒阻化剂等技术还存在一些不足,提出一种以水泥灰为基料的三相泡沫来预防硫化矿石自燃的新技术。该技术是将水泥灰和水按一定的比例混合,同时加入一定比例的发泡剂和稳泡剂后,经物理机械方式发泡形成,集固、液、气三相材料的防灭火性能与一体。理论分析了水泥灰三相泡沫的形成与衰变机理,并通过正交试验,对三相泡沫的发泡倍数与半衰期进行研究,最后采用单因素实验,定量分析灰水质量比,发泡剂和稳泡剂浓度对三相泡沫稳定性能的影响,得到最佳泡沫配方。结果表明:当灰水质量比为1:5,发泡剂浓度为5g/L,稳泡剂浓度为8g/L时,制得的三相泡沫发泡倍数达到6倍,半衰期达到6h以上。     

Optimization and implementation of a foam system to suppress dust in coal mine excavation face

Foam technology is more efficient than water sprays for dust control in coal mines, but the traditional foam system is complex and poses problems related to foam production and spraying application, with high water consumption, unstable equipment and relatively low utilization efficiency of foam. This paper describes an optimized foam system which overcomes these disadvantages. The proposed foam generator has a self-suction unit that uses a turbulent-flow water jet to automatically draw in ambient air and foaming agent, thereby eliminating the need for compressed-air hoses and pipes. As well as simplifying the system, it solves the current problem of water backflow created by high-pressure compressed air. A refined foam spraying structure was developed for use in conjunction with an operating roadheader as it produces and diffuses dust. The structure consists of foam distribution supports and arc-fan nozzles. It can produce a more focused, continuous and uniform coverage at the source of the dust. The optimized system consumes less water and foaming agent, and achieves greater dust-suppression efficiency than methods in current use.     

掘进工作面可调控双锥形一体化泡沫降尘装置的实验研究

为解决掘进时粉尘浓度高、能见度低的问题,达到改善作业环境并减少对工作人员危害的目的。运用流体力学的涡流和射流原理,研发出可调控双锥形一体化泡沫降尘装置,通过多次模拟实验确定其最佳的技术原理、设计结构及操作方法。凭借系统调节部件设计气-液二相控制面板,实现对气液比的调节与监控。实验表明:通过对阀门的调节,泡沫降尘过程中可以实现气液比的调控,能够产生连续、均匀的泡沫,发泡剂最佳浓度为2.5%,泡沫回收装置能有效的回收积液。全尘、呼尘降尘效率分别达到93.4%和90.2%,起到全面立体控尘的效果。该装置能够对矿井综掘面高效降尘,成泡量与粒径准确控制,实现不同矿井不同粒度尘源的控制。     

溜井泡沫抑尘剂的研制及其抑尘性能实验研究

矿山溜井卸矿过程中产生的大量冲击性粉尘已成为矿井可呼吸性粉尘的主要来源,为了有效解决溜矿井卸矿时产生的大量冲击性粉尘,基于泡沫抑尘的机理,研究了发泡倍数和半衰期两个指标进行优选实验,通过正交法和单因素法优选出最佳的泡沫抑尘配方为十二烷基硫酸钠、月桂酸钠和聚丙乙酰胺,各成分的质量浓度分别为0.6%、0.8%与0.4%。结果表明,通过模拟溜井卸矿测得不同泡沫高度的抑尘效率在85%~95%之间,呼吸性粉尘的抑尘效率为87%左右,其时效性可达2h以上。     

纳米氢氧化铝三相泡沫制备研究*

为更好地解决煤矿采空区煤炭自燃问题,以十二烷基硫酸钠为主体进行发泡剂复配,通过泡沫性能测试实验,研制出高性能发泡剂。以纳米氢氧化铝作为固相颗粒,制备出发泡倍数高、稳定性强的纳米氢氧化铝三相泡沫,使用锥形量热仪研究其高温阻燃能力和消烟性能。实验结果表明:当纳米氢氧化铝的质量分数从0提高到1%时,泡沫体积从500 mL增长至830 mL;当质量分数从3%提高到4%时,泡沫析液半衰期由15 min提升至42 min,且能在完全析液后保留三维网状结构。在高温阻燃和消烟能力方面,纳米氢氧化铝三相泡沫的加入将点燃时间从24 s延长至87 s,持续燃烧时间从835 s缩短至325 s,热释放速率高峰值从97.2 kW/m2降低至49.8 kW/m2,烟气生成速率峰值从0.064 m2/s降低至0.012 m2/s,对CO,CO2释放速率也有一定抑制作用。     

固化剂对矿用充填泡沫固化行为的影响

为提高泡沫的充填堵漏风效果,选取有机强酸A,有机磺酸B,无机强酸C等3种固化剂,通过测定泡沫的发泡时间、发泡温度、承压强度和氧指数等参数,分析不同组合固化剂对矿用充填泡沫固化行为的影响。结果表明:乳化时间、起泡时间和表干时间随固化剂用量的增加而明显缩短;泡沫的发泡倍数和发泡温度随固化剂用量的增加而增加;单独使用有机强酸A或有机磺酸B时,泡沫都存在不同程度的收缩,当添加较高量的无机强酸C时,泡沫的尺寸稳定性变好。当复合固化剂有机强酸A用量∶有机磺酸B用量∶无机强酸C用量=1.2∶1∶1时,泡沫的固化效果最优。     

Experimental study on advantages of foam–sol in coal dust control

In China, more than 2.65 million coal mine workers are exposed to coal dust. Every year, new pneumoconiosis cases amount to 25,000, among which 6000 cases die of this disease. The figure is twice the death toll in production safety accidents. Occupational diseases seriously endanger life and health of coal mine workers, and restrict the healthy growth of the coal industry.The paper presented a study of foam–sol-based coal dust control. This was an experimental study of characteristics of foam–sol-based coal dust control, which features dust capture, suppression, and isolation. Comparative wettability experiments were carried out to determine contact angles of water, aqueous foam, and foam–sol solution. A new foam–sol generating system with a conical diffuser outlet was proposed.The experiment results clearly showed that the foam–sol features dust capture, suppression, and isolation. The wettability of the aqueous foam solution was better than the foam–sol solution, but the foam–sol technology had the better ability to capture the airborne dust, suppress the static dust and enclose the dust source, due to the excellent surface viscosity, strong cohesiveness and less volatile property. The paper concluded that the foam–sol could greatly improve the dust control efficiency and did not have main deficiencies that the aqueous foam technology had.     

防治煤矿火灾的凝胶泡沫材料制备及其性能研究*

为解决纯水玻璃（WG）凝胶泡沫强度低、泡沫稳定性差易破碎,凝胶固水性差等问题。将保水剂和成膜剂引入WG凝胶泡沫中,对水玻璃凝胶泡沫进行优化设计,最终制备出保水性高、泡沫稳定性高、成膜性好的WG凝胶泡沫。研究结果表明:WG凝胶泡沫材料的最佳复配体系是发泡剂为十二烷基醇醚硫酸酯钠（AES）和十二烷基硫酸钠(SDS)按1∶2比例复配,浓度为0.8%,胶凝剂WG浓度为8%,交联剂NaHCO3浓度为2%,聚丙烯酰胺浓度为0.4%,成膜剂A浓度为1%,保水剂B浓度为0.3%;改性后WG凝胶泡沫具有更加紧密的网状结构,稳定性好,并且具有较好的成膜性,常温下半衰期达40 d;阻化实验表明,100 ℃此凝胶泡沫阻化率高达78.35%,能有效减缓煤的氧化放热速率抑制自燃;煤堆燃烧实验表明,改性后WG凝胶泡沫能有效抑制煤的燃烧,防止煤复燃。     

综掘工作面除尘技术研究与应用

主要分析了通风除尘、除尘器除尘、喷雾除尘、煤层注水除尘、控尘技术、泡沫除尘的技术特点。新型泡沫抑尘技术在邢台煤矿的现场应用证明了泡沫抑尘技术具有除尘效率高、能改善作业环境等特点,尤其对呼吸性粉尘能有效抑制,具有较好的推广应用前景。     

压缩空气蛋白泡沫抑制液体火的有效性研究

压缩空气泡沫灭火技术是一项新型灭火技术,为验证压缩空气泡沫系统与蛋白泡沫灭火剂结合使用时是否可以成为含PFOS泡沫灭火剂的替代技术,开展了压缩空气蛋白泡沫抑制液体火有效性试验.在对压缩空气蛋白泡沫的泡沫性能进行分析的基础上,进一步采用标准油盘火试验模型对压缩空气蛋白泡沫的灭火性能进行评估,并与吸气式泡沫产生系统进行了对比.试验结果表明压缩空气蛋白泡沫具有优异的泡沫性能,同时具备抑制非水溶性液体火的有效性,可以作为含PFOS泡沫灭火剂的替代技术.     

危化品泄漏围堵材料理化性能及燃烧行为研究

针对易燃液体泄漏围堵问题,开发了1种可快速发泡的酚醛泡沫材料,对其表观密度、耐水性、耐酸性、耐碱性、氧指数、燃烧行为及产烟成分进行系统研究。研究结果表明:发泡材料在中性和酸性液体环境中表现出良好的耐受性;在碱性环境中稳定性降低,由于共轭效应,导致分子中的H+遇碱性环境发生中和反应;发泡材料的氧指数和锥形量热测试参数（热释放速率、总热释放量及总生烟量等）表明该材料具有良好的耐火性;发泡原料中的含硫交联剂是其燃烧产烟生成较高浓度SO2的主要原因。     

综掘工作面气水联动除尘装置影响因素及应用效果分析

为掌握气水联动除尘装置影响因素及现场除尘效果,以便更好应用于现场实际。基于煤矿综掘工作面长压短抽通风控除尘系统,利用数值仿真和正交实验设计分析方法,系统研究除尘装置叶片参数、进风量和进风口位置等因素对除尘效果的影响规律。研究结果表明：叶片安装角为40°,扭转角为4°时,除尘器入口处负压值和进风量最大,而吸风口距工作面5 m、吸风量≥300 m³/min时的除尘效果较好。控除尘系统采用气水联动除尘装置后,各测点全尘除尘效率提高了40.8%～55.4%,呼吸性粉尘除尘效率提高了31.4%～41.3%,应用效果良好。     

液氮泡沫发生器内流动特性研究

低温液氮与泡沫混合液直接接触产生氮气泡沫是一种新型的掺混形式,利用液氮高汽化比的特点,搭建液氮泡沫可视化实验装置,进行氮气-水两相流及液氮泡沫流动特性的研究。结果表明,液氮相变产生大量氮气,其与泡沫液混合产生泡沫,温度有所回升,最终趋于泡沫混合液温度;管路沿程压降较小;液氮射流破碎及流动过程可分为6个区域:低温液氮区、向上循环翻滚区、滞留区、泡沫与泡沫混合液混合区、致密泡沫区、泡沫混合液区。流体向下游流动过程中持续发泡;为防止管路结冰,需合理控制泡沫混合液与液氮流量。     

综采机组隔尘风帘的设计与应用效果研究

受民用建筑大门空气幕的启发 ,将“洁净空调技术”中的“洁净棚理论”,创新并应用于综采工作面的防尘工程 ,设计了能阻止采煤机在截煤过程中产生的呼吸性粉尘向司机处扩散的隔尘装置——风帘。此革新装置的原理和作用是以形成透明的“空气幕墙”将采煤司机工作区与采煤机截煤区分隔 ,阻止呼吸性粉尘向司机处扩散。在邢台矿务局葛泉煤矿 132 6综采工作面进行的现场试验表明 :该装置对呼吸性粉尘有较好的隔尘效果 ,平均隔尘效率为 72 %以上。     

水成膜泡沫对变压器油池火的窒息特性研究

水成膜泡沫在油类表面的窒息作用是扑灭油类火灾的重要机理之一,针对自行开发的快速型泡沫灭火剂开展了其对油池火的窒息灭火特性研究。首先通过老化试验测试了泡沫液的热稳定性,然后对比了不同成分泡沫液在25#变压器油表面的铺展特性,之后研究了不同发泡倍率和成分的泡沫液对油池火的窒息灭火效果及影响规律。研究发现,铺展性能不佳的泡沫液会逐渐丧失窒息能力,而铺展性能优异的泡沫液能持续发挥窒息作用。提升泡沫液热稳定性有利于在油面形成稳定的液膜,隔绝氧气并降低可燃分子挥发速率。此外,发泡倍率较低的泡沫液的流动性更强,在相同液体流量条件下低倍数泡沫的窒息灭火效果更优。自研的快速型泡沫灭火剂在热稳定性和铺展性能两方面均具备优良的性能,因此其窒息灭火效率和抗复燃能力优于现有的大部分同类泡沫灭火剂。     

复配超细粉体三相泡沫的制备与稳定性研究

为改善泡沫灭火剂的高温稳定性和抗复燃性能,将石墨粉、膨润土和空心玻璃微珠按一定比例复配加入泡沫灭火剂中制备防灭火三相泡沫,利用自主设计的实验台架,研究其发泡、稳泡及油面热稳定性等主要性能,分析复配超细粉体对泡沫灭火剂稳定性的影响机理。实验证明,复配粉体的加入可使泡沫灭火剂在高温下的稳定时间延长10倍以上,粉体颗粒会在泡沫表面形成一层致密壳层,增强泡沫的隔热阻燃性能,石墨粉的存在使壳层更加致密且增强了泡沫的流动性,但会对泡沫的发泡性能产生较大的影响,当空心玻璃微珠和石墨粉的添加质量比为5∶2时,整体效果较好。