Influence of coal particles on methane/air mixture ignition in a heated environment

The temperature at which coal dust glows is normally much lower than the auto-ignition temperature (AIT) of methane/air mixtures, and thus a better understanding is needed regarding methane/air ignition in a heated environment in the presence of coal particles. A horizontal tube apparatus was used to test the effect of brown coal and two kinds of bituminous and anthracite on methane/air combustibility. For the four coal samples tested, the presence of coal particles significantly reduced the minimum temperature for ignition of methane/air mixtures in a heated environment. No. 1 bituminous coal with 12 mm diameter decreased the ignition temperature value from 595 to 500 °C. It is thought that pre-ignition of low-AIT volatiles emitted from the heated coal particles ignited the methane/air mixtures. Volatiles, sulfur content, and large porosity of piled coal particles all enhanced ignition of methane/air mixtures in a hot environment, while water content and small particle size reduced ignition. For anthracite, no ignition occurred when temperatures of the heated environment were lower than the AIT of methane (595 °C), except for the 12-mm-diameter sample. Anthracite did not readily ignite methane/air mixtures and the ignition mechanism was somewhat similar to that of a burning cigarette.     

Quantitative risk analysis of urban natural gas pipeline networks using geographical information systems

This paper presents a novel quantitative risk analysis process for urban natural gas pipeline networks using geographical information systems (GIS). The process incorporates an assessment of failure rates of integrated pipeline networks, a quantitative analysis model of accident consequences, and assessments of individual and societal risks. Firstly, the failure rates of the pipeline network are calculated using empirical formulas influenced by parameters such as external interference, corrosion, construction defects, and ground movements. Secondly, the impacts of accidents due to gas leakage, diffusion, fires, and explosions are analyzed by calculating the area influenced by poisoning, burns, and deaths. Lastly, based on the previous analyses, individual risks and social risks are calculated. The application of GIS technology helps strengthen the quantitative risk analysis (QRA) model and allows construction of a QRA system for urban gas pipeline networks that can aid pipeline management staff in demarcating high risk areas requiring more frequent inspections.     

RETRACTED:

Jianfeng Li  Sandra M.Y. Lee  Wenmao Liu 《Process Safety and Environmental Protection》2013,91(3):213-220

Emergy analysis of cassava vinasse treatment

Vinasse has great pollution to the environment. A number of technologies have been explored for reducing the pollution of vinasse. Sustainability has become an important factor when discussing wastewater treatment techniques. Emergy analysis was used to evaluate the treatment of cassava vinasse in this paper. Cr (emergy consumption ratio) as a new emergy index was proposed to measure the impact of waste treatment to the society. Centrifugal solid–liquid separation, UASB (up-flow anaerobic sludge bed), and SBR (sequencing batch reactor activated sludge process) are used in the treatment process. The emergy indices for cassava vinasse treatment system were as follows: EYR (emergy yield ratio) was 6.20, ELR (environmental loading ratio) was 5.81, ESI (emergy sustainability index) was 1.07, and Cr was 4.60E+12 sej/m³. The emergy of coal electricity accounts for 46% of all purchased inputs. It is necessary to improve the treatment technology to reduce the electricity used.     

人体装甲测试用模拟破片的应用与发展

模拟破片是人体装甲防弹性能测试评价的主要试验弹体.本文对人体装甲和模拟破片进行了阐释,分析了模拟破片的应用背景,对国内外现状进行了对比分析,对标准模拟破片的确定以及爆炸破片的发展进行了探讨,提出了开展新型模拟破片及其测试技术研究的重要意义.     

地铁车站及隧道全尺寸火灾实验研究(3)—车站隧道火灾

为了研究烟气在地铁车站隧道内的蔓延特征,及在车站隧道通风排烟系统、区间隧道通风排烟系统及车站公共区通风排烟系统联合排烟情况下烟气控制效果,在一地铁车站隧道内开展了全尺寸火灾实验.实验研究了车站隧道顶部横向排烟作用下的烟气扩散规律,及烟气的温度变化,分析了屏蔽门开关状态下烟气与空气的卷吸混合特性,及区间风机的气流组织对通风排烟的影响.实验结果对于地铁车站隧道火灾防排烟设计提供了数据支持.     

电磁辐射职业危害及防护对策

科技飞速发展的今天,射频及微波技术已经广泛应用于国民经济的各个领域,这使得越来越多的从业人员在工作场所受到电磁辐射污染的影响。本文总结归纳了我国电磁辐射职业危害状况,分析了现代企业电磁辐射防护的新特点,并提出企业电磁辐射防护对策。     

生产安全事故风险分级与分级监察研究

针对我国安全生产形势严峻现状，为进一步提高安全生产监察效率和质量，强化行政执法力度，提出了在我国建立生产安全事故风险分级与分级监察系统，其方法是首先确定行业相对风险度，再计算企业职业伤害风险系数，据此对企业风险进行分级，根据监察力量和监察计划对不同风险级别的企业进行分级监察，为实行集约型安全生产监察工作提供参考。     

人误因素树构建技术研究

运用人误因素辨识多视图法进行因素辨识,建立了详细的因素辨识表;把人的行为分为5个阶段,即系统状态监测阶段,目标分析阶段,方案确定阶段和行为执行阶段.分别分析各个阶段可能的人误原因及模式;以组织视图为例,根据因素辨识和人误原因及模式分析结果,阐述人误因素树的构建过程,最终得到了1个完整的人误因素树.     

排水管网设计中管材的选择

排水管网使用的各类排水管材种类繁多,性能差异较大.根据排水管材的材质、性能分析,对常用几种排水管材进行了技术经济比较.以实际工程为例,概述了不同施工条件和不同地质条件下排水管材的设计选择方法.