高温煤气脱硫——Ⅱ.锌铁基脱硫剂的化学形态

HIGH-TEMPERATURE DESULPHURIZATION OF COAL GAS Ⅱ. CHEMICAL CONSTITUTION OF Zn/Fe-BASED SORBENT

应用穆斯堡尔谱考察了不同的制备条件对锌铁基脱硫剂相态组成的影响。提高焙烧温度和延长焙烧时间均有利于ZnFe_2O_4的形成,但焙烧温度过高引起过度烧结从而降低了脱硫剂的活性。原脱硫剂中的ZnFe_2O_4和α-Fe_2O_3在脱硫过程中转化成零价铁、碳化铁和硫化铁,此外还形成了一定数量的高自旋Fe^(2+)含铁相。再生处理后脱硫剂的化学组成基本上可恢复至起始状态。

Mssbauer effect was used to study the chemical constitution of Zn/Fe—based sorbents prepared under different Conditions. The higher the temperature and the longer the time for calcination are the moreZnFe_2O_4 will be formed in the sorbent. As much as 72.8% by wt. of ZnFe_2O_4 was obtained after 45 min calcining at ca. 800℃. Lower reactivity was obtained for sorbents calcined above a certain temperature, because excessive calcinination resulted in sintering of the sorbent. The Mssbauer spectra of sulphurized and regenerated sorbents were also studied. It was found that Fe, θ-Fe_3C and FeS were the main Fe-phases in the sulphurized sorbent and the composition of the sorbent could be restored to that of the original oxide by regeneration.