钙基水合改性飞灰吸附剂脱除模拟烟气中SO_2的实验研究

The Study on the Adsorption Performance of SO_2 with Activated Fly Ash from the Simulated Flue Gas

对燃煤电厂废弃物飞灰进行水合改性制备飞灰吸附剂,并将其用于模拟烟气中进行SO_2的脱除。实验结果表明,飞灰经水合改性后,其脱硫能力得到极大提高。在水合过程中,水合时间、飞灰、CaO和CaSO_4所占比例对改性飞灰吸附剂的脱硫效率都有一定影响。其中影响最大的因素是水合时间,水合时间越长,其脱硫效果越好。CaO和CaSO_4的加入,可以有效改善飞灰吸附剂的表面结构,从而提高吸附剂脱硫能力;BET和FTIR结果表明,水合时间越长,其孔隙结构越好,脱硫能力也越强;SO_2的主要活性吸附位为C—O—C和—OH。该改性飞灰吸附剂脱除SO_2既包括物理吸附又包括化学吸附。在最佳制备条件下制得的水合改性飞灰吸附剂的最大硫容为1430.1μg/g。

Fly ash is the solid waste from the coal-fired power plant,and it was used to prepare activated fly ash sorbent by hydration reaction. Then the sorbent was used to adsorpt SO_2 from the simulated flue gas. The results show that the adsorption capacity of fly ash sorbent is extremely improved after hydration reaction. The ration of fly ash,CaO and CaSO_4,and hydration time all have influence on the adsorption efficiency. The most influence factor is the hydration time,and the longer hydration time leads to the better adsorption ability. The addition of CaO and CaSO_4 can improve the surface characteristics of fly ash,and it is helpful for adsorpting SO_2. The results of BET and FTIR show that the longer hydration time brings about the better pore structure,and it improves the SO_2 removal capacity. The groups of C—O—C and—OH are main adsorption sites of SO_2. Physical adsorption and chemical adsorption both exist in the adsorption process. The activated fly ash sorbent which was prepared under the optimum preparation conditions has the highest sulfur capacity of 1 430. 1 μg/g.