Research On Denitriifcation Performance Of Titanium-based Manganese Series Low-temperature SCR Catalysts

As one of the most effective technologies of controlling the NitrogenO_xides （NO_x） emissions currently， selective catalytic reduction denitrationtechnology uses ammonia as reducing agent. The regular SCR technology needs highreaction temperature. Besides，a dust removal processing is needed before thereaction to avoid the interference effect on the catalyst. Therefore，this articlepresents my research of low-temperature catalyst.Different components of MnO_x/TiO₂、MnO_x-CeO₂/TiO₂、Mn-Cu-Ce/TiO₂、Mn-Cu-La/TiO₂、MnO_x-La₂O₃/TiO₂-ZrO₂catalysts have been prepared by usingimpregnation method. The effects of variables （including catalyst’s active ingredients,the content of additives and supports） on the denitration performance of catalyst havebeen studied during the catalytic activity testing. And the results show that catalystwith the ratio of20%MnO_x/TiO₂、8%MnO_x^-12%CeO₂/TiO₂and that with the ratio of7%Mn-4%Cu-9%La/TiO₂have the best denitration activity. When MnO_xand La₂O₃loading content are10%and space velocity is10000h^-1，denitrification rate can bekept in the range of90%at150-200℃over MnO_x-La₂O₃/TiO₂-ZrO₂catalyst.Influence of SO₂and H₂O on denitrification performance of catalyst have beenstudied. The results show that the activity of MnO_x/TiO₂have been greatly affect bySO₂and H₂O，it indicates that the catalysts have less ability of resistance to SO₂andH₂O poisoning. With the add of additives of CeO₂in MnO_x/TiO₂catalyst，theperformance of resistance to SO₂and H₂O is improved and the denitrificationefficiency with the existence of SO₂and H₂O is obvious higher than MnO_x/TiO₂catalyst. Mn-Cu-La/TiO₂catalyst is susceptible to poisoning when only SO₂exists influe gas; but it has excellent ability of resistance to H₂O；apparently，when SO₂andH₂O co-existe in the flue gas，catalyst will have much better performance ofpoisoning resistance when only SO₂exists in the flue gas. While MnO_x-La₂O₃/TiO₂-ZrO₂catalysts have good resistance to SO₂and H₂O performance. The effect over Mn-Cu-La/TiO₂and MnO_x-La₂O3/TiO₂-ZrO₂catalysts byreaction temperature，NO initial concentration，space velocity，O₂concentration,NH₃/NO ration have been studied. With the decrease of space velocity, and theincrease of NH₃/NO ration， O₂concentration， NO initial concentration，denitrification rate shows an increasing trend.Dynamic analysis of Mn-Cu-La/TiO₂have been carried out. On the premise ofremoving influence of internal and external diffusion，then according to arrheniusformula to calculate the activation energy of the reaction and the index factor，reaction order of NO and reaction order of O₂have been attained by computing，thusthe reaction rate equation of Mn-Cu-La/TiO₂catalyst can be attained.