对天然气水合物预防管理保障安全生产的研究

为了保障陆上气田冬季天然气安全生产,防止因天然气水合物导致安全事故,采用鱼骨图法对陆上气田天然气水合物产生的原因进行系统分析。分析显示,导致天然气水合物产生的根本原因,出现在天然气产能建设和日常生产管理各环节,以及单井、输气管道和集气站各生产场所,为防止天然气水合物产生,针对原因采用5W1H法进行管理,从而达到对冬季天然气生产主要安全风险进行有效控制的目标。     

Ag_6P_2W_(18)O_(62)/TiO_2/膨胀石墨复合光催化剂的制备及甲基橙的降解

以钛酸四丁酯为钛源、膨胀石墨(EG)为载体,通过溶胶凝胶-浸渍法制备了Ag_6P_2W_(18)O_(62)/TiO_2/EG复合光催化剂。采用SEM,EDS,XRD,FTIR,UV-vis等技术对其进行表征,研究了该催化剂在紫外光及可见光下对甲基橙的降解性能。表征结果显示:Ag_6P_2W_(18)O_(62)被成功负载到TiO_2上且保持Dawson结构;经Ag_6P_2W_(18)O_(62)表面修饰后的复合光催化剂可见光吸收性能增强;EG提供的丰富孔道有利于有机污染物吸附去除。实验结果表明:在甲基橙质量浓度为20 mg/L、催化剂加入量为1.0 g/L、反应温度为25℃的条件下,n(Ag)∶n(Ti)=1∶16时的复合光催化剂(ATE-2)的紫外光、可见光催化活性最佳;紫外光下反应70 min时甲基橙去除率为96.5%,可见光下反应40 h时甲基橙去除率为83.5%;ATE-2使用5次后,反应70 min时,其甲基橙去除率仍为92.5%。     

相对端面比对旋风除尘器主要性能的影响

为了提高旋风除尘器的分离效率,利用RSM湍流模型构建三维旋风除尘器模型,研究了相对端面比对旋风除尘器主要性能的影响。数值模拟结果表明,随着相对端面比的减小,总压和切向速度随之降低,颗粒的停留时间缩短,因而提高了分离效率,为旋风除尘器的结构优化设计提供参考。     

Effects of a carbon monoxide-dominant gas mixture on the explosion and flame propagation behaviors of methane in air

This work aimed to experimentally evaluate the effects of a carbon monoxide-dominant gas mixture on the explosion characteristics of methane in air and report the results of an experimental study on explosion pressure measurement in closed vessel deflagration for a carbon monoxide-dominant gas mixture over its entire flammable range. Experiments were performed in a 20-L spherical explosion tank with a quartz glass window 110 mm in diameter using an electric spark (1 J) as the ignition source. All experiments were conducted at room temperature and at ambient pressure, with a relative humidity ranging from 52 to 73%. The peak explosion pressure (P_max), maximum pressure rise rate ((dp/dt)_max), and gas deflagration index (K_G) were observed and analyzed. The flame propagation behavior in the initial stage was recorded using a high-speed camera. The spherical outward flame front was determined on the basis of a canny method, from which the maximum flame propagation speed (S_n) was calculated. The results indicated that the existence of the mixture had a significant effect on the flame propagation of CH₄-air and increased its explosion risk. As the volume fraction of the mixed gas increases, the P_max, (dp/dt)_max, K_G and S_n of the fuel-lean CH₄-air mixture (7% CH₄-air mixture) increase nonlinearly. In contrast, addition of the mixed gas negatively affected the fuel-rich mixture (11% CH₄-air mixture), exhibiting a decreasing trend. Under stoichiometric conditions (9.5% CH₄-air mixture), the mixed gas slightly lowered P_max, (dp/dt)_max, K_G, and S_n. The P_max of CH₄-air mixtures at volume fractions of 7%, 9.5%, and 11% were 5.4, 6.9, and 6.8 bar, respectively. The S_n of CH₄-air mixtures at volume fractions of 7%, 9.5%, and 11% were 1.2 m/s, 2.0 m/s, and 1.8 m/s, respectively. The outcome of the study is comprehensive data that quantify the dependency of explosion severity parameters on the gas concentration. In the storage and transportation of flammable gases, the information is required to quantify the potential severity of an explosion, design vessels able to withstand an explosion and design explosion safety measures for installations handling this gas.     

闪速炉排烟用电收尘器的大修和改造

对贵溪冶炼厂炼铜闪速炉排烟系统用电收尘器的大修和改造进行了详细的论述,并总结出了一套适合本厂电收尘器大修的经验。     

超长回采工作面微震特征的影响因素研究*

为探讨超长工作面微震特征影响因素,采用微震监测技术研究42108工作面微震事件的空间分布特征及冲刷构造、推进速度、矿压对煤岩体微震事件特征的影响机制。研究结果表明:微震事件集中发生于工作面辅运巷侧,微震事件的空间分布受临近采空区、上覆煤层煤柱影响较大;微震事件能量和空间分布特征与推进速度相关性较差,当推进速度超过5.5 m/d后,微震事件频次、总能量与推进速度呈正相关;过冲刷构造时工作面推进速度降低,微震能量、频次的稳定性较差,易造成大能量积聚,使工作面危险性增大;微震事件集中发生位置与矿压值较大区域相吻合。     

地面风场风速测量标准装置需求与设计

针对地面风场中风速测量仪器计量测试的需求,提出了风速测量标准装置的组成及性能指标设计要求,详细分析了风速测量标准装置各个重要部件的设计关键技术,结果表明该设计科学合理。     

An estimation of vehicle kilometer traveled and on-road emissions using the traffic volume and travel speed on road links in Incheon City

The objective of this study is to estimate the vehicle kilometer traveled (VKT) and on-road emissions using the traffic volume in urban. We estimated two VKT; one is based on registered vehicles and the other is based on traffic volumes. VKT for registered vehicles was 2.11 times greater than that of the applied traffic volumes because each VKT estimation method is different. Therefore, we had to define the inner VKT is moved VKT inner in urban to compare two values. Also, we focused on freight modes because these are discharged much air pollutant emissions. From analysis results, we found middle and large trucks registered in other regions traveled to target city in order to carry freight, target city has included many industrial and logistics areas. Freight is transferred through the harbors, large logistics centers, or via locations before being moved to the final destination. During this process, most freight is moved by middle and large trucks, and trailers rather than small trucks for freight import and export. Therefore, these trucks from other areas are inflow more than registered vehicles. Most emissions from diesel trucks had been overestimated in comparison to VKT from applied traffic volumes in target city. From these findings, VKT is essential based on traffic volume and travel speed on road links in order to estimate accurately the emissions of diesel trucks in target city. Our findings support the estimation of the effect of on-road emissions on urban air quality in Korea.     

Effect of scale on flame speeds of methane-air

Explosions are the main types of accidents causing casualties in underground coal mines. Research on the mechanisms of gas explosions is needed as a basis for the development of techniques and strategies for explosion prevention, suppression, and mitigation. The prevention of loss in explosion accidents and inquiries into their causes require understanding of the explosion process of methane in air. Because of the high cost and safety issues in full scale experiments, the experiments with small scale ducts have become a key alternative approach. Whether the experimental results at small scales agree with those at full scales needs to be investigated to validate the significance of the experimental results at small scale. Numerical simulation was used to obtain the explosion characteristics of a methane-air mixture in a gallery or duct. If the grid size is too fine in the numerical simulation for a methane-air explosion it is difficult to calculate using the present computer resource. If the grid size is too coarse, the considerable error may result. The effect of grid size on results of calculation depends on the scenario being investigated. The effect of grid sizes on simulation accuracy was analyzed in this work. The overpressure and temperature distributions and the flame propagation for the deflagration of methane-air mixtures in a gallery or duct were obtained by the AutoReaGas code at three different scales. The geometry of investigated objects and the grids in the calculation domain were similar in the three cases. The calculated overpressures vary with the scale. The calculated temperatures do not vary with the scale for the three cases.     

驾驶员感知特性对隧道群交通安全的影响

针对高速公路隧道群对驾驶员感知特性的影响,以驾驶员的感知特性与高速公路隧道群行车安全的关系为研究对象,采用速度估计测试仪和深度知觉测试仪,在"铜汤高速-安徽段"沿线对高速公路隧道群行车途中的160名驾驶员进行实地测试,所得数据进行t检验和方差分析,用灰色建模软件V2.1进行关联度分析。结果表明:驾驶员的速度估计特性与高速公路隧道群驾驶员的年龄、驾龄以及连续行车时间具有较强的相关性,其中连续驾车时间的影响最大。年龄对驾驶员深度知觉准确性无显著影响;驾龄、连续行车时间对驾驶员的深视力准确性有显著影响。