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研究了硫化NiW/Al2O3催化剂上的NO分解反应、H2还原NO反应以及H2同时还原NO和SO2反应.在活性评价及XRD和XPS表征的基础上提出了H2同时催化还原SO2和NO的反应机理.结果表明,NO在硫化催化剂上可以完全分解,但由于催化剂晶格硫遭到严重氧化,因此还伴随着SO2的生成.该氧化作用导致了催化剂中晶格硫的大量流失和催化剂的失活;在NO反应体系中引入等摩尔的H2后,晶格硫的流失速度减缓,流失程度得到一定抑制.这是因为H2能与晶格硫竞争消耗NO解离出的Oad,此外,被氧化的晶格硫一部分还可进一步被还原,返回到催化剂晶格;在SO2和NO同时还原体系中,550℃时,SO2和NO的转化率都可达到100%,单质硫产率超过90%.稳定性测试表明,10 h后催化剂仍能保持高活性,没有发生失活.这主要是因为反应气中的SO2能够被H2还原为元素硫物种,从而可以对晶格硫进行源源不断的补充.
The NO decomposition reaction, H2 reduction NO reaction and H2 reduction NO and SO2 reaction on NiW / Al2O3 catalyst were studied. The reaction mechanism of simultaneous H2 reduction of SO2 and NO was proposed based on the activity evaluation and XRD and XPS characterization. The results show that NO can be completely decomposed on the sulfided catalyst, but due to the severe oxidation of the lattice sulfur of the catalyst, SO2 is also accompanied by the formation of SO2, which results in the massive loss of the lattice sulfur and the deactivation of the catalyst. The introduction of equimolar amounts of H2 in the NO reaction system slowed down the rate of loss of the lattice sulfur and inhibited the degree of loss because the H2 competed with the lattice sulfur to dissipate Oad, which liberated NO. In addition, the oxidized crystal Part of the metgesulfur can be further reduced and returned to the catalyst lattice. In the simultaneous reduction of SO2 and NO, the conversion of SO2 and NO can reach 100% and the elemental sulfur yield over 550% at 550 ℃. The results showed that the catalyst remained high after 10 h without deactivation, which was mainly because the SO2 in the reaction gas could be reduced to elemental sulfur species by H2, so that the sulfur could be continuously replenished.