Comparative studies on fouling of homogeneous anion exchange membranes by different structured organics in electrodialysis

Five negatively charged organic compounds with different structures, sodium methane sulfonate (MS), sodium benzene sulfonate (BS), sodium 6-hydroxynaphthalene-2-sulfonate (NSS), sodium dodecyl sulfate (SDS), and sodium dodecyl benzene sulfonate (SDBS), were used to examine the fouling of an anion exchange membrane (AEM) in electrodialysis (ED), to explore the effect of molecular characteristics on the fouling behavior on the AEM and changes in the surface and electrochemical properties of the AEM. Results indicated that the fouling degree of the AEM by the different organics followed the order: SDBS?>?SDS?>?NSS?>?BS?>?MS. SDBS and SDS formed a dense fouling layer on the surface of the AEM, which was the main factor in the much more severe membrane fouling, and completely restricted the transmembrane ion migration. The other three organics caused fouling of the AEM by adsorption on the surface and /or accumulation in the interlayer of the AEM, and exhibited almost no influence on the transmembrane ion migration. It was also concluded that the organics with benzene rings caused more severe fouling of the AEM due to the stronger affinity interaction and steric effect between the organics and the AEM compared with organics with aliphatic chains.     

安全仪表功能的实现与验证

以石化装置安全仪表系统为例,叙述了如何进行安全仪表系统设计,重点阐述了安全仪表设计过程中应该注意的几个问题。     

过程工业防护层分析及其应用

防护层分析是一种简化的半定量危险性评价方法,目前主要应用于过程工业的危险性分析与评价过程中。该方法通过评价防护层有效防护的概率来判断现有防护措施是否满足系统安全需要。本文介绍了防护层分析的方法、程序,并将其应用于化工过程工业实例分析中,同时对防护层分析方法今后的发展趋势进行了展望。     

石化行业安全仪表系统及其安全完整性等级确定方法

介绍了石化行业安全仪表系统及其安全完整性等级确定方法,并对方法的应用范围进行了说明。     

DO对水解酸化池与好氧MBR组合工艺运行效果的影响研究

针对溶解氧（DO）、气水比对水解酸化池与好氧MBR组合工艺处理污水效果的影响和能耗问题．从气水比对DO的影响,DO对COD与色度去除效果的影响等方面来讨论气水比,溶解氧以及污水处理效果之间的最佳运行点。试验结果表明。在P（MLSS）分别为5．81、4．25、2．19g／L的运行条件下,MBR的最佳气水比为39：1、28．1.18：1;DO变化速率随污泥浓度的下降而升高;DO的变化对COD、色度的去除效果影响并不显著。     

生物加强超滤深度处理城市中水过程膜污染与清洗效果分析

金桥电厂采用生物加强超滤工艺对城市二级排放水进行深度处理,清水用于锅炉循环冷却水补给水。在连续半年的运行期间没有产生严重膜污染情况,通过反洗、在线反洗、鼓风曝气和适当操作条件能很好的防治并预防膜污染,保证系统的稳定运行。     

电厂二氧化碳捕集分离技术研究综述

电厂二氧化碳捕集与封存是二氧化碳减排措施研究热点,也是全球二氧化碳减排的重要任务之一,可分为物理吸附/吸收、化学吸收、物理-化学吸收、膜技术及生物技术等。其中物理吸附/吸收、化学吸收为电厂二氧化碳捕集主流技术。开发具有高选择性、高效率吸收剂及捕集技术,提高能源利用效率,合理布置尾部烟气脱碳处理设施是电厂二氧化碳捕集技术面临的挑战。     

自动喷水冷却系统保护下钢化玻璃作为防火分隔物可行性试验研究

针对目前大型综合性商业建筑拟采用钢化玻璃作为防火分隔物的使用需求,通过建立实体试验模型研究在自动喷水冷却系统保护下钢化玻璃作为防火分隔物有效性,并进而提出可行的自动喷水冷却系统保护方案。研究结果表明：快速响应型洒水喷头在高温烟气作用下可及时启动并对玻璃进行冷却保护,使钢化玻璃完整性未受到破坏,且玻璃背火面温度和热辐射强...     

Mitigating the Effects of Landscape Development on Streams in Urbanizing Watersheds

This collaborative study examined urbanization and impacts on area streams while using the best available sediment and erosion control (S&EC) practices in developing watersheds in Maryland, United States. During conversion of the agricultural and forested watersheds to urban land use, land surface topography was graded and vegetation was removed creating a high potential for sediment generation and release during storm events. The currently best available S&EC facilities were used during the development process to mitigate storm runoff water quality, quantity, and timing before entering area streams. Detailed Geographic Information System (GIS) maps were created to visualize changing land use and S&EC practices, five temporal collections of LiDAR (light detection and ranging) imagery were used to map the changing landscape topography, and streamflow, physical geomorphology, and habitat data were used to assess the ability of the S&EC facilities to protect receiving streams during development. Despite the use of the best available S&EC facilities, receiving streams experienced altered flow, geomorphology, and decreased biotic community health. These impacts on small streams during watershed development affect sediment and nutrient loads to larger downstream aquatic ecosystems such as the Chesapeake Bay.     

Rapid Geomorphic and Habitat Stream Assessment Techniques Inform Restoration Differently Based on Levels of Stream Disturbance

Visual‐based rapid assessment techniques provide an efficient method for characterizing the restoration potential of streams, with many focusing on channel stability and instream habitat features. Few studies, however, have compared these techniques to see if they result in differing restoration priorities. Three rapid assessment techniques were contrasted at three wild trout streams in western New York with different amounts of channel disturbance. Two methods focused only on geomorphic stability, whereas the third addressed physical habitat condition. Habitat assessment scores were not correlated with scores for either geomorphic assessment method and they varied more between channels with different degrees of disturbance. A model based on dynamic equilibrium concepts best explains the variation among the streams and techniques because it accounts for a stream's capacity to maintain ecological integrity despite some inherent instability. Geomorphic indices can serve as effective proxies for biological indices in highly disturbed systems. Yet, this may not be the case in less disturbed systems, where geomorphic indices cannot differentiate channel adjustments that impact biota from those that do not. Dynamically stable streams can include both stable and unstable reaches locally as characterized by geomorphic methods and translating these results into restoration priorities may not be appropriate if interpretations are limited to the reach scale.