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The poisoning mechanisms of different zinc species on a ceria-based NH3-SCR catalyst and the co-effects of zinc and gas-phase sulfur/chlorine species.
Journal of Colloid and Interface Science ( IF 9.4 ) Pub Date : 2020-01-17 , DOI: 10.1016/j.jcis.2020.01.058
Xiaoqiang Wang 1 , Yue Liu 1 , Zhongbiao Wu 2
Affiliation  

Low-medium temperature NH3-SCR technology has been applied for years in municipal solid wastes incineration (MSWI) to control the emissions of nitrogen oxides. Unlike coal-fired flue gases, the tail gas from MSWI contains high levels of heavy metals in fly ash, especially the zinc species, which may harm SCR catalysts. As such, in this paper, the deactivation mechanism of different zinc species (ZnO, ZnSO4 and ZnCl2) on the Sb-CeZr2Ox catalysts and the co-effects of zinc species and gas-phase pollutants (including SO2 and HCl) were investigated. The experimental results indicated that the deactivation rate of various poisoning zinc species was in the order of ZnCl2 > ZnSO4 > ZnO. Moreover, the interactions between zinc and antimony species would disrupt the structure of the Sb-Ce mixed oxides to decrease the redox ability, consequently suppressing the ammonia activation and NO adsorption. Furthermore, such damaging effects on catalyst structures would promote the formation of bulk-like sulfate species in the presence of SO2, resulting in a decreased mobility of surface oxygen species, which significantly decrease the sulfur resistance. However, the presence of HCl did not show an evident co-effect on the Zn poisoned sample owing to the limited coverage of the chlorine deposition.

中文翻译:

二氧化铈基NH3-SCR催化剂上不同锌物质的中毒机理以及锌和气相硫/氯物质的共同作用。

多年来,中低温NH3-SCR技术已应用于城市固体废物焚化(MSWI)中,以控制氮氧化物的排放。与燃煤烟气不同,MSWI的尾气在飞灰中含有高含量的重金属,尤其是锌,这可能会损害SCR催化剂。因此,本文研究了不同的锌物种(ZnO,ZnSO4和ZnCl2)在Sb-CeZr2Ox催化剂上的失活机理,以及锌物种和气相污染物(包括SO2和HCl)的共作用。实验结果表明,各种中毒锌的失活速率依次为ZnCl2> ZnSO4> ZnO。此外,锌与锑物种之间的相互作用会破坏Sb-Ce混合氧化物的结构,从而降低氧化还原能力,因此,抑制了氨的活化和NO的吸附。此外,对催化剂结构的这种破坏作用将促进在SO 2存在下块状硫酸盐物质的形成,导致表面氧物质的迁移率降低,这显着降低了耐硫性。但是,由于氯沉积物的覆盖范围有限,HCl的存在对Zn中毒样品没有显示出明显的共同作用。
更新日期:2020-01-17
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