我国瓦斯灾害防治技术及手段探究

瓦斯灾害是我国煤矿主要灾害之一,我国煤矿能否安全生产在很大程度上要取决于瓦斯灾害的治理效果。我国煤矿瓦斯灾害存在着发生因素多,治理难度大等顽症,这对于我国煤矿安全技术人员始终是工作的症结所在。本文通过分析目前煤矿瓦斯灾害治理工作现状和趋势,提出了我国煤矿在此方面面临的挑战和急需开展的研究工作。在此基础上综合分析了我国瓦斯治理技术的发展过程中常用的瓦斯灾害治理技术及手段。以期煤矿技术人员因地制宜,采取相应措施治理瓦斯灾害,保证生产安全。     

变频节电技术在炼钢厂高压电动机上的应用

中天钢铁集团有限公司第二烧结厂、第二炼铁厂的10台高压电机依靠管道的风门调节风量,致使管道阻力增大,容易使管道积灰堵塞,浪费电能。采用变频节能技术对10台高压电动机进行改造,提高电动机运行效率,节约电能,降低生产成本。     

绿色低钠盐生产技术研究

绿色低钠盐由地下卤水经自然蒸发,浓缩成饱和卤水后,再利用太阳光照自然蒸发制成,有溶解速度较快、味咸而不苦、久放不结块等特点。文章介绍了一种利用新工艺生产的绿色低钠盐的特点,详细探讨了生产绿色低钠盐的工艺条件,并对低钠盐市场进行了分析。     

APG压注工艺在中压互感器制造中的应用

介绍了环氧树脂自动压力凝胶(APG)工艺应用于中压互感器制造的基本原理,以及国内应用该工艺压注成型中压互感器的基本情况.     

改进型冷却水管坝后预留槽设计与应用

冷却水管坝后预留槽施工关系到冷却水管连接、坝面外观和后期封堵等问题。采用传统的预留槽布置方案,需要进行预埋木盒的制作、安装以及拆除后的二期混凝土回填等工作,这些工作费工费时,且容易产生质量缺陷。介绍了一种改进型预留槽施工工艺,即在冷却水管外露端头绑扎土工布代替传统的预埋木盒。分析比较表明,该方法可有效减少施工成本和缩短工期,具有很强的推广价值。     

防晃电技术及其在石化行业中的应用

由于石化行业具有工艺复杂,技术密集,高温高压和连续生产的特殊性质,针对其供电系统发生晃电时带来的不良影响,必须采取有效的防晃电技术来解决问题。为此,在重点分析晃电产生的原因、对供电回路的影响后,对5种常见防晃电技术的优、缺点进行了分析比较。最后介绍某石化企业在炼油区的几套关键装置上采用再启动控制器实现相关设备的晃电再启动的应用情况。     

Combinations of selected physical and chemical hurdles to inactivate Escherichia coli O157:H7 in apple and orange juices

This study evaluated the individual and combined efficacies of physical processing techniques such as heating, Dynashock multi-frequency ultrasound waves, ultraviolet-C (UV-C), and additives such as sodium benzoate, potassium sorbate, α- and β-Pinene for pasteurization of orange and apple juices against acid-adapted Escherichia coli O157:H7. In heated apple juice, log-linear inactivation of the test organism resulted in D values which were used to calculate for the recommended 5-log reduction process schedules (t_5D) at 45, 50, 52, 55, and 60 °C equal to 481.5, 103.6, 45.0, 22.4, and 10.54 min, respectively. E. coli O157:H7 exhibited biphasic inactivation composed of a slow inactivation lag, followed by log-linear inactivation in ultrasound-treated juice. t_5D schedules were similarly calculated at 54.7 and 77.5 min for orange and apple juice, respectively. Lethal rate analyses in the ultrasound-treated apple juice revealed that 85% of the reduction in E. coli population was due to the heat liberated by cavitation. Combined ultrasound and UV-C treatment resulted in greater inactivation rates in both juices, with greater efficacy in apple juice. Supplementation of all tested additives, whether singly or in combination, similarly resulted in significantly shorter t_5D schedules in both juices.     

Dissemination of safety messages in IEEE 802.11p/WAVE vehicular network: Analytical study and protocol enhancements

Multi-channel IEEE WAVE 1609.4 protocol has been proposed to guarantee the co-existence of safety and non-safety applications over the same Vehicular Ad hoc NETwork (VANET) scenario. While the usage of multi-channel avoids the risk of collisions between applications allocated on different frequencies, its implementation on a single-radio transceiver poses some major concerns about the effective utilization of the channel resources. In this paper, we study the performance of safety applications over multi-channel single-radio VANETs, and we present three novel contributions in this regard. First, we propose an analytical analysis and a simulation study of IEEE 1609.4. We show the harmful impact of synchronous channel switching on the message delay and delivery ratio. Second, we investigate the problem of dissemination of safety broadcast messages over multi-channel VANETs, where the network is intermittently disconnected, due to the alternation of control and service intervals. Finally, we propose a WAVE-enhanced Safety message Delivery (WSD) scheme to enable fast dissemination of safety messages over multi-channel VANETs, while guaranteeing compatibility with the existing WAVE stack. To this aim, we formulate the dissemination problem as a multi-channel scheduling problem. We further introduce cooperation among vehicles to reduce the dissemination latency. Simulation study shows the ability of the WSD scheme to enhance the performance of IEEE 1609.4 in terms of message delay and delivery ratio under different topologies and various applications.     

深圳抽水蓄能电站监控新技术应用研究与实践

通过对安防、工业电视和门禁等新技术的研究,设计了一套先进的监控系统,包括硬件平台、系统管理、应用软件,利用深圳抽水蓄能电站已形成的光纤网络通道把分布在方圆10 km范围内多个站端设备以环路的方式连接起来,把可靠成熟的新技术融合到整个平台。自首台机组成功投运,监控系统为电站正常运行保驾护航,高清摄像机、视觉识别、行为分析、边界防护等新技术的应用为工程项目增添了亮点,使电站现场管理更加智能化、规范化。     

Performance analysis of a double calcium looping‐integrated biomass‐fired power plant: Exploring a carbon reduction opportunity

Integrating biomass energy generation with carbon capture will result in “carbon neutral” to “carbon negative” technology. Countries like India and China possess significant reserves of limestone. Calcium looping (CaL) technology can prove to be a promising option for carbon capture in these countries. The present work aims at improving the performance of CaL‐integrated biomass‐fired power plant (BFPP) by exploring different looping configurations. In this study, (i) standalone BFPP, (ii) conventional CaL (single stage), and (iii) double CaL‐integrated BFPP have been systematically evaluated. A comparative performance evaluation of these three plants in terms of energy, exergy and ecological assessment, has been carried out. A detailed parametric study and unit‐wise exergy analysis of the best configuration among the three are presented to identify the scope for further improvement in efficiency and energy savings.