新型改性粉煤灰对燃煤烟气中二氧化硫的吸附性能研究

Study on Adsorption Performance of New Modified Fly Ash for Sulfur Dioxide in Coal-fired Flue Gas

粉煤灰经过改性以后能够大大提升其吸附能力,以Na_(2)SiO_(3)·9H_(2)O作为化学激发剂,采用化学改性法制备了一种新型改性粉煤灰吸附剂GX-FA,并考察了二氧化硫体积分数、含湿量、烟气流速以及实验温度对GX-FA吸附模拟燃煤烟气中二氧化硫的影响。实验结果表明:在相同的实验条件下,随着二氧化硫体积分数的不断增大,脱硫率逐渐降低,穿透时间则逐渐缩短;而随着新型改性粉煤灰GX-FA吸附剂含湿量、烟气流速的逐渐增大以及实验温度的逐渐升高,脱硫率均呈现出“先增大后减小”的趋势,而穿透时间均呈现出“先延长后缩短”的趋势。当模拟燃煤烟气中二氧化硫的体积分数为0.3%时,最佳吸附条件为:吸附剂含湿量为25%,烟气流速为350 L·h^(-1),实验温度为100℃。研究结果说明,新型改性粉煤灰GX-FA吸附剂对燃煤烟气中二氧化硫的吸附能力较强,在最佳吸附条件下可以长时间的保持较高的脱硫效率。

After modification,the adsorption capacity of fly ash can be greatly improved.Using Na_(2)SiO_(3)·9H_(2)O as a chemical activator,a new modified fly ash adsorbent GX-FA was prepared by chemical modification method.The effects of sulfur dioxide volume fraction,moisture content,flue gas flow rate and experimental temperature on the adsorption of sulfur dioxide in simulated coal-fired flue gas by GX-FA were investigated.The experimental results showed that under the same experimental conditions,with the increasing of volume fraction of sulfur dioxide,the desulfurization rate gradually decreased,and the penetration time gradually shortened;With the gradual increase of moisture content of the new modified fly ash adsorbent GX-FA,as well as the increase of flue gas flow rate and experimental temperature,the desulfurization rate showed a trend of"increasing first and then decreasing",while the penetration time showed a trend of"extending first and then shortening".When the volume fraction of sulfur dioxide in simulated coal-fired flue gas was 0.3%,the best adsorption conditions were as follows:the moisture content of adsorbent 25%,the flue gas flow rate 350 L·h^(-1),and the experimental temperature 100℃.The results show that the new modified fly ash GX-FA adsorbent has strong adsorption capacity for sulfur dioxide in coal-fired flue gas,and can maintain high desulfurization efficiency for a long time under the optimal adsorption conditions.