燃煤电站袋式除尘器的运行及维护管理

为了保证袋式除尘器的安全、稳定、经济、环保运行,确保袋式除尘器优异的除尘性能,需要加强对袋式除尘器的运行、维护管理。本文分别说明了袋式除尘器初期运行、正常运行两个阶段的除尘机理。阐述了袋式除尘器维护管理方面需要注意的问题以及必须做好的工作内容,并细化了维护管理内容及维护方案。     

控制PM2.5的除尘技术概述

国家目前已增设PM2.5浓度限值日报项目,空气质量标准也将PM2.5纳入新指标。在现有标准和技术条件下,实用高效且经济可行的控制PM2.5的技术措施主要有湿式电除尘器、凝并器和电袋混合式除尘器,本文通过实例概述了这几种控制PM2.5的除尘技术的应用效果。     

Electroreductive dechlorination of chlorophenols with Pd catalyst supported on solid electrode

Electroreductive dechlorination of chlorophenols with Pd catalyst supported on solidelectrode was studied. As solid electrodes, carbon cloth (CC), carbon felt (CF) and titanium mesh were used, and palladium was plated on solid electrodes by either electrolytic or electroless method. On each electrode with Pd, chlorophenols were qualitatively dechlorinated to phenol, while they were entirely intact on electrodes without Pd. Moreover, neither base electrode nor plating method significantly affected the activity of Pd as far as it was sufficiently loaded on the electrode. Based on the results in the experiments using one electrode repeatedly, Pd catalyst proved to possess a satisfactory duarability under the present condition. It was suggested that the reactive species responsinble for the dechlorination of chlorophenols could be formed during preliminary electrolysis. Thus, (Pd)_x-H resulting from the adsorption of electrogenerated hydrogen on metallic Pd might be assumed most probable.     

高温烟气中颗粒静电脱除特性的实验研究

研究温度90~450℃条件下静电除尘器的放电特性及除尘特性,分析温度、工作电压、烟气流速及颗粒浓度等关键参数对于颗粒静电脱除效率的影响.结果表明,当温度从90℃上升至450℃,在比收尘面积为46.5m²/(m³·s^-1),粉尘初始浓度约为750mg/Nm³的工况下,颗粒脱除效率均可达到98%以上.随着电压升高,除尘效率不断提高,但其升高趋势逐渐变缓.在相同电压下,随着温度的上升,电晕电流显著增大,强化颗粒荷电,颗粒的脱除效率提高;而在相同电流下,高温下较低的空间场强使得颗粒的驱进速度减小,导致颗粒脱除效率下降.烟气流速提高降低了颗粒的脱除效率,PM_1.0受烟气流速的影响较PM₁₀更为明显.颗粒初始浓度的上升增强了颗粒的碰撞及团聚作用,在一定程度上有利于增强颗粒的脱除效果.     

火电厂烟气中汞的分布特征和排放特点

调查南京市某一燃煤火电厂100 MW机组,在两种不同的工况下,对该锅炉废气中的汞污染物进行现场测试,选取三个监测点位,分别为静电除尘器进口、出口及湿法脱硫装置出口,分析煤质燃烧烟气中汞不同形态的监测结果,得到静电除尘器和湿法脱硫装置对汞的脱除效率,总结火电厂烟气中汞的污染物的分布特征及其排放特点。火电厂燃烧的废气中汞来源于煤质中的汞,主要以气相部分汞形态存在,90%以上的汞以气态汞形态排放到烟气中,固相部分汞含量较少。静电除尘器对总汞有着相当高的脱除效率,湿法脱硫装置对总汞的脱除率较低。     

我国西北典型大城市大气可吸入颗粒物浓度分布特征

我国西北地区冬季寒冷、春季多风沙天气,空气中的可吸入颗粒物(PM10)浓度较高,利用兰州、西宁、乌鲁木齐、银川、呼和浩特等城市2000年6月～2007年12月每日浓度最高的大气主要污染物(SO2,NO2,PM10)浓度资料,研究了5个省会城市PM10分布特征。结果表明,五个城市PM10污染都较严重,PM10为主要污染物的日数每月平均超过20天。五个城市的季节分布特征类似,冬春季浓度较高,平均值都达到了国家二级污染标准,夏秋季相对低一些。其中,兰州和乌鲁木齐冬季浓度值远高于其他城市。五个城市均属煤烟沙尘型污染,但煤烟和沙尘的影响程度有所不同。     

Psychological interventional approach for reduce resource consumption: Reducing plastic bag usage at supermarkets

A field study was conducted to investigate the reduction of plastic bag usage at supermarkets. Many behaviors leading to potential damage to the environment may be unintentional. This study applied a dual motivation model to plastic bag usage and examined the effects of an intervention aimed at promoting pro-environmental behavior. A voice prompt intervention was implemented in Japanese supermarkets. In the first (control) week, shoppers were given free plastic bags by the cashier. In the second (intervention) week, cashiers asked shoppers whether they wanted plastic bags. We collected observational and questionnaire measures of variables that predicted free plastic bag usage during the intervention. The results supported a dual motivation model of behavioral change. The voice prompt decreased the usage of plastic bags by both discouraging unintentional usage and encouraging an intentional reduction in usage. Possibilities for interventions designed both to attenuate unintentional motivation and to promote intentional motivation are considered.