Mn基脱硝催化剂抗水抗硫改性的模拟与实验研究

Simulation and experimental study on modification of water and sulfur resistance by Mn-based denitration catalyst

为考察ZSM-5分子筛作载体和Ce掺杂对催化剂低温脱硝活性及抗水抗硫性的影响,通过分子动力学模拟和实验研究的手段研究了载体类型、掺杂Ce对催化剂性能的影响。分子动力学模拟发现,ZSM-5分子筛作载体较γ-Al2O3明显抑制H2O在其表面的吸附,在活性组分中添加Ce既抑制H2O在其表面的吸附,又减轻SO2对催化剂的毒化作用。实验研究发现,Mn-Fe-Ce/ZSM-5催化剂性能更优,Ce的添加对提高催化剂的低温脱硝活性和抗水抗硫性能具有明显的积极作用,ZSM-5分子筛作为载体也对提高催化剂抗水性能起到重要作用。通过SEM、XRD、BET、TG-DTG等表征手段和BaCl2鼓泡实验对Mn-Fe-Ce/ZSM-5催化剂抗硫性提高的原因分析发现,添加Ce使催化剂储氧释氧能力提高,将烟气中的SO2氧化为SO3并被烟气携带,避免了SO2与催化剂活性组分的反应,则催化剂表面的活性组分不被破坏,保证了催化剂的催化反应性能。

To investigate the effect of ZSM-5 zeolite as carrier and Ce doping on the low temperature denitrification activity and water/sulfur resistance of the catalyst,the effects of carrier type and Ce doping on the performance of the catalyst were studied by molecular dynamics simulation and experimental research.Molecular dynamics simulations showed that ZSM-5 zeolite as a carrier significantly inhibited the adsorption of H2O on its surface compared withγ-Al2O3.Adding Ce to the active component not only inhibited the adsorption of H2O on its surface,but also mitigated the poisoning effect of SO2 on the catalyst.The experimental study found that Mn-Fe-Ce/ZSM-5 has better denitration activity under low temperature and water/sulfur resistance.The addition of Ce has a positive effect on improving the low temperature activity and water/sulfur resistance of the catalyst.ZSM-5 zeolite as carriers also play an important role in improving the water resistance of the catalyst.The SEM,XRD,BET,TG-DTG and other characterization methods and BaCl2 bubbling experiments were carried out to analyze the mechanisms for the improvement of sulfur resistance of Mn-Fe-Ce/ZSM-5 catalyst.It was found that the addition of Ce increased the oxygen storage and oxygen release capacity of the catalyst.Oxidation of SO2 in the flue gas to SO3 avoids the reaction of SO2 with the active component,so that the active component on the surface of the catalyst is not destroyed,and the catalytic reaction performance of the catalyst is ensured.