高温烟气中吸附剂捕集K的模型及其反应动力学研究

Modeling and reaction kinetics study on K capture by adsorbents in high temperature flue gas

针对生物质燃烧时采用吸附剂控制烟气中含K气体成分行为的性能描述,采用一维柱塞流反应器模型探究高岭土和煤灰捕集KOH(K2CO3)、KCl和K2SO4的性能及影响因素。通过模型计算与文献实验值比较检验模型合理性和确定动力学参数,并比较高岭土和煤灰捕集不同含K成分的性能差异。结果表明,采用表观动力学模型和单一的动力学参数可预测广泛反应条件下高岭土和煤灰捕集K的量,所确定的动力学参数是合理的;在给定的K浓度和烟气温度范围内,单位质量高岭土和煤灰捕集K的规律相似,均随烟气温度的升高而增大,随K浓度的增大而增大,且高岭土捕集能力受K浓度影响更明显;高岭土和煤灰捕集K的能力均为KOH强于KCl,强于K2SO4,且高岭土捕集能力明显强于煤灰。

Aiming at the performance description of using adsorbent to control the behavior of K-containing gas in flue gas during biomass combustion, the performance and influencing factors of kaolin and coal fly ash trapping KOH (K2CO3), KCl and K2SO4 were investigated by one-dimensional plug flow reactor model. After comparing the model calculations with the experimental measurements in the literature to verify the rationality of the model and to determine the kinetic parameters, the differences in the performance of kaolin and coal fly ash adsorbing various Kcontaining gases were compared. The results showed that employing the global kinetic model and a single set of kinetic parameters was capable of predicting the amount of K captured by kaolin and coal fly ash under a wide range of reaction conditions and the kinetic parameters determined were reasonable. Within the given ranges of K concentration and flue gas temperature, the patterns of K capture by kaolin and coal fly ash were similar, both increasing with the increase of flue gas temperature and K concentration, but the effect of K concentration on kaolin adsorption was more obvious. The capabilities of K adsorption by both kaolin and coal fly ash were: KOH > KCl > K2SO4, but the adsorption capability of kaolin was much stronger than coal fly ash.