Study on the preparation of novel NiB/Hβ-Al2O3 micro-mesoporous suppressant and its inhibition mechanism of coal dust explosion flame

Coal dust explosion is one of the serious accidents in the coal industry. It is of great significance to study the flame suppression of coal dust explosions. In this paper, a novel active component NiB with amorphous structure for explosion suppression was synthesized by the chemical reduction method. Furthermore, the novel explosion suppressant NiB/Hβ-Al₂O₃ was prepared through the kneading method by loading novel amorphous NiB nanoparticles on Hβ-Al₂O₃ with the micro-mesoporous structure as the carrier. The morphology and structure of NiB/Hβ-Al₂O₃ were characterized by XRD, BET, SEM, and FTIR, which showed that the NiB/Hβ-Al₂O₃ has proper pore structure and NiB nanoparticles are uniformly distributed as active components for explosion suppression in suppressant. Hartmann tube was used to evaluate the inhibition of coal dust deflagration. The results showed that the flame propagation distance and velocity decreased with the increase of the explosion suppressant. When the addition of explosion suppressant was 30 wt%, the explosion of coal dust was suppressed effectively. Furthermore, combing with the analysis results of the products after coal dust deflagration, the physical and chemical inhibition mechanism of the novel NiB/Hβ-Al₂O₃ explosion suppressant on coal dust deflagration was put forward.     

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.     

跳态洗煤废水处理及回用技术的研究

比较了几种无机混凝剂对洗煤废水的处理效果,确定了采用CaCl2作为混凝剂,联合有机絮凝剂PAM处理洗煤废水。结果表明:最佳条件如下,400mL水样中10%的CaCl2溶液加入量为6mL,浓度为0.2%的PAM 6mL,分别以120r/min的搅拌速度搅拌,搅拌90s,最后将水样沉淀25min。     

空气和煤气吹脱法处理高氨氮废水的对比研究

研究了在实验室使用空气吹脱法去除高浓度氨氮废水的条件,通过正交实验得出其影响因素大小顺序为:废水pH>气液比r>废水温度tw>表面活性剂浓度c,最佳吹脱条件为pH=11.0,r=550,c=10mg/L,tw=75℃,最高氨氮去除效率达到71.4%。在某焦化厂以终冷塔后焦炉煤气为解吸介质,现场试验影响因素大小顺序为:o废水pH>废水温度tw>气液比r>煤气温度tg>表面活性剂浓度c,最佳吹脱条件为pH=11.5,tw=90℃,r=650,tg=55℃,c=20mg/L。为煤气吹脱解吸回收氨工艺的应用提出了建议。     

Assessing determinants of industrial waste reuse: The case of coal ash in the United States

Devising effective strategies to facilitate waste reuse depends on the solid understanding of reuse behaviors. However, previous studies of reuse behavior have been limited in scope, focusing mostly on household recycling behaviors or very limited types of industrial wastes. To gain a better understanding of the business reuse behaviors, this study examined the impact of various factors in technical, economic, regulatory, and behavioral categories in the case of coal ash generated in the United States. The results of fixed effect models for fly ash and bottom ash particularly showed the significance role of the behavioral factor. In both models, a proxy variable, which represents knowledge sharing among the power plants or the utility's decision-making, turned out to be statistically significant and had the largest coefficient estimates among a group of variables. This finding may imply that the characteristics of waste reuse behavior are determined more by business decision-making behaviors than by market or institutional factors. However, the role of the behavioral variable was stronger in the bottom ash models than in the fly ash models. While the reuse of bottom ash was determined primarily by the behavioral variable, fly ash reuse was determined by more diverse factors including economic and regulatory variables. This could be explained by material characteristics in relation to competing resources and the nature of reuse applications.     

塑性石膏浆防治煤炭自燃性能研究

综述了国内外喷注型浆体防煤自燃技术的现状和发展趋势,通过实验,得出塑性石膏浆的配制方案和堵漏风效果。结果表明：在井下高湿环境中,塑性石膏浆不仅具有良好的附着性、充填性和保塑性,而且用料单一、成本较低、无毒无害,满足防治煤炭自燃对喷注型材料的基本要求,有利于提高煤矿生产的安全保障程度。     

Changes in the reaction regime during low-temperature oxidation of coal in confined spaces

A study of the initial stage of the low-temperature oxidation of coal is important, not only for the prevention for fires in coal industry, but also in reducing emissions of hazardous gases. A batch reactor was introduced and a series of simulated experiments of coal oxidation was carried out in this paper. The time-dependent rates of CO emission and oxygen consumption during oxidation experiments of coal samples with different particle size ranges were obtained simultaneously from the measurements of CO and O₂ concentration in the reactor. The experimental results show that the rate of CO emission presents three stages in the duration of coal oxidation. Based on the rates of oxygen consumption, the reaction order and reaction rate were obtained from the reaction rate equation. These results indicate that the reaction regime switches during coal oxidation in confined spaces. The initial decrease of reaction rate is due to the decrease of the active sites in coal. While the decrease of reaction rate in the following period of coal oxidation is attributed to the reaction-inhibition mechanism of oxidation products. And it is mainly represented by the chemisorption sequence of coal oxidation. The oxidative activity of coal can be restored when the oxidation products are evacuated. A mechanism of low-temperature oxidation of coal in confined spaces was also suggested.     

论燃煤过程中的放射性污染

国内煤层中普遍存在的天然放射性核素，通过燃煤产生的烟气、煤灰渣等介质进入空气、土壤和水环境中。公众健康危害评价结果证明燃煤排放的放射性污染物通过吸入途径对人体的总危害危险大于二氧化硫、氨氧化物等一般污染物。鉴于我国近几年火电厂等煤炭消耗量大，并且不断增长的现状，指出对燃煤造成的放射性环境污染应予足够的重视。     

Mortality rate and population density regulation in the great tit, Parus major L.: A review

A comparative analysis of published estimates of survival rates in different populations of great tits is made separately for adult and juvenile birds. The relationship between environmental conditions and demographic parameters in the reproduction of populations is discussed. Published in Russian in Ekologiya, 2006, No. 3, pp. 199–207. The article was translated by the author.     

煤吸附氧的过程特性研究

分析了煤吸附氧的动态变化过程并将其划分为活性吸附阶段、变能级吸附阶段和趋势化吸附阶段 ;测试了不同变质程度典型煤样的吸氧过程曲线 ,得出了滞后时间和斜率常数是煤表面位置能分布及空隙结构特性的表征量。分别由吸附动力学理论及煤氧吸附过程曲线推导了煤吸氧速度方程 ,建立了煤吸氧过程特性的数学描述模型 ,得出了煤的吸附活化能与覆盖度之间存在着对数关系。特别指出吸氧速度是煤表面与氧结合性质的度量因子 ,在一定程度上量化了煤的自燃活化性能。