共热解法制备污泥-秸秆吸附剂及其烟道气脱汞性能研究

Preparation of adsorbent by co-pyrolysis of sewage sludge and corn stalk and its performance for mercury removal of flue gas

城市污水厂污泥的处理是世界性难题,亟需研究开发高效、环保、低成本的处理工艺.将某生活污水厂消化污泥和玉米秸秆共热解制备吸附剂,考察了制备条件如污泥-秸秆混合比例、热解终温、热解恒温时间等对吸附剂脱汞性能的影响.结果表明,吸附剂的脱汞性能随着玉米秸秆配入量的增加而增大.热解终温低于650℃时,吸附剂的脱汞性能随着温度的升高而提高;而热解终温升至700℃时,脱汞性能有所下降;热解恒温时间对吸附剂脱汞性能影响较小.污泥-秸秆吸附剂的优化制备条件为:污泥与秸秆配比50%、热解终温为650℃、热解恒温时间为20min,此时吸附剂的模拟烟气汞吸附量达到86.5μg/g.

Disposal of sewage sludge is a worldwide challenge,so the development of efficient,environmental and low-cost treatment technology is in urgent need.A kind of new adsorbent was prepared by co-pyrolysis of sewage sludge from wastewater treatment plant and corn stalk.The effects of preparation parameters including the ratio of corn stalk to sewage sludge,pyrolysis temperature and pyrolysis time on the performance for mercury removal of flue gas were investigated.The results show that the mercury adsorption capacity of the adsorbent increases with the increase of the ratio of corn stalk to sewage sludge.When the pyrolysis temperature is lower than 650 ℃,the mercury adsorption capacity increases with the pyrolysis temperature,then it tends to decrease when the temperature is over 700℃.Meanwhile,the effect of pyrolysis time is relatively slight.The optimized preparation parameters generating highest mercury removal capacity of 86.5μg/g are as follows：ratio of corn stalk to the sewage sludge（dry basis）being 50%,pyrolysis temperature being 650℃and pyrolysis thermostatic heating time being 20 min.