Study On Sulfur Resistance Of Copper-based Denitration Catalyst For Catalytic Cracking Regeneration Flue Gas

In the petrochemical industry,the fluid catalytic cracking(FCC)device is one of the important sources of nitrogen oxides(NO_x)in the air.With the increasing attention of the country to environmental protection issues,the requirements for the emission of NO_x pollutants are becoming more and more stringent.The widely used FCC flue gas denitration catalysts have the disadvantages of narrow active temperature window and easy poisoning.It is imperative to study FCC flue gas denitration catalysts with wider active temperature window and good resistance to sulfur poisoning.The aim of this article is to prepare a denitration catalyst with good antioxidant and sulfur poisoning performance.In this paper,a series of supported copper-based denitration catalysts were prepared by supersaturation impregnation method,and the activity of catalysts was evaluated by simulating FCC regeneration flue gas in a fixed bed reactor.The structure of the catalysts were characterized by XRD,H₂-TPR and BET methods.1.A series of CuO/Al₂O₃ catalysts were prepared.The effects of CuO loading,calcination temperature,different additives(Ce,Cr,Fe,Co,Ni,Mn)on catalytic denitration activity were tested,and the resistance to sulfur and oxygen of the particular catalyst was further explored.The results showed that(1)The suitable loading amount of CuO was 15%,the suitable calcination temperature of the catalyst precursors was 700?,and the most suitable addtive was Cr with its suitable addition ratio was50%,in the meantime,the catalyst CCr-50 had the best denitration activity and its NO conversion rate reached 99%at 330?.(2)CCr-50catalyst showed a certain sulfur poisoning resistance.its NO conversion still kept above 90%in the range of 370?700?with SO₂ concentration of 0.03%.(3)CCr-50 catalyst had good anti-oxidation and anti-sulfur poisoning ability,its NO conversion rate still kept above 80%in the range of 340?700?under the atmosphere of SO₂(0.01%)and O₂(0.04%).2.CeO₂ and ZrO₂ were used to modify the CuO/Al₂O₃ catalyst carrier,and then the additive Cr was added to investigate the effect of Cr₂O₃ addition ratio on the catalystic denitration activity.The anti-oxygen and anti-sulfur poisoning performance of the particular catalysts was explored.The research showed that(1)The suitable composite carrier was CeO₂-Al₂O₃and the catalyst had the best denitration activity with the sutible CeO₂ addition ratio was 50%,it gaving NO conversion rate reached 99%at 343?.(2)The denitration activity of the CuO-Cr₂O₃/CeO₂-Al₂O₃ catalyst Rat-10 was the best with the addition ratio of Cr₂O₃ of 10%,and its NO conversion rate reached 99%at 273?.(3)The Rat-10 catalyst had good anti-sulfur performance,and when the concentration of SO₂ is 0.05%,its NO conversion rate reached 99%in the range of 650?700?.(4)Rat-10 catalyst had better anti-oxidation and anti-sulfur performance in the atmosphere of 0.01%SO₂ and 0.04%O₂,when the reaction temperature was stayed at 300?350?or 700?,its NO conversion still kept above 95%.3.A series of CuO/ZrO₂ catalysts were prepared.The effects of CuO loading,calcination temperature,addition ratio of additive Ce and carrier modification(Ti,Si,Zn,La,Al)on catalytic denitration activity were investigated.The antioxidant and sulfur poisoning performance was further explored for the particular catalyst The results showed that(1)The suitable CuO loading amount was 5%,the suitable calcination temperature of catalyst precursors was 700?and the most suitable CeO₂ addition ratio was 50%.(2)The ZTi-10 catalyst had the best denitration activity with the most suitable composite carrier of Ti O₂-ZrO₂ and possessing 10%Ti O₂ doping ratio,its NO conversion rate reached 99%at 310?.(3)The catalyst ZTi-10 had poor sulfur resistance and sulfur resistance,and its anti-oxidation and anti-sulfur poisoning perfoamence were worse.In the atmosphere of 0.01%SO₂ and0.04%O₂,the highest NO conversion rate of the ZTi-10 catalyst was only 43%.