电除尘凝聚预处理技术对提钒转炉烟气除尘超低排放的影响

针对提钒转炉烟气粉尘中10μm及以下粒级的含量高于脱碳转炉,较难达到超低排放要求的问题,本文提出对提钒转炉一次烟气进行溶液喷雾凝聚预处理,再利用干式电除尘器进行静电吸附的工艺方法,并对3种凝聚剂进行了凝聚效果试验。结果表明,KGM-g-PDMC凝聚效果最好,可以使100%除尘粒径降到120μm,对10μm粒级以上大小颗粒物除尘效率达到了70%,而且通过适当增大凝聚剂浓度、降低烟气温度,可以增加KGM-g-PDMC的凝聚效果。通过对有、无凝聚剂处理的粉尘进行扫描电镜检测,发现凝聚预处理不同于静电吸附作用,凝聚作用不单使得颗粒物粒径变大,而且可以发生链式附聚耦合效应,使得比表面积进一步增大,更加有利于后续颗粒的继续附聚耦合。该附聚耦合工艺采用的凝聚剂KGM-g-PDMC经济合理,处理后的提钒转炉烟气可以满足超低排放要求,而且投资小于开发新型电除尘器,具有推广价值。

Adsorption of Chromium （Ⅵ） from Aqueous Solution Using Zeolite/Chitosan Hybrid Composite

This study investigated the adsorption ability of ZCHC （zeolite/chitosan hybrid composite） as adsorbent for chromium （Cr（Ⅵ））, ZCHC was prepared with sol-gel method by mixing zeolite and chitosan. Adsorption experiment from aqueous solutions containing known amount of Cr（Ⅵ） using zeolite, chitosan and ZCHC was explored to evaluate the efficiency of ZCHC as adsorbent for Cr in a batch system. The amount of Cr（Ⅵ） adsorbed at different pH values, initial concentrations, adsorbent dosages, and contact times were determined by ICP-AES （inductively coupled plasma-atomic emission spectrometry） in order to determine the optimum conditions for Cr（Ⅵ） adsorption. Furthermore, the adsorption mechanism of Cr（Ⅵ） by zeolite, chitosan and ZCHC was investigated by applying Langmuir and Freundlich isotherm equations to the data obtained. In addition, the rates of adsorption were found to conform to pseudo-second order kinetics.