进行了铁基磁流化床SCR烟气脱硝实验研究,并对铁基床料进行了BET和XRD分析。结果表明,在0.01—0.015T磁场下,180℃时的SCR脱硝效率达90%,将高效脱硝温度范围从无磁场时的220-250℃扩展至180-250℃。其原因主要在于辅加磁场降低了SCR反应的表观活化能,改善了Fe2O3催化剂的SCR活性。磁流化床中Fe2O3催化剂SCR脱硝反应的磁场效应可归纳为:磁场强化NO在Fe2O3表面的磁化学吸附;磁场促进活性自由基NH2的生成以及自由基NH2与NO的反应;磁场流态化良好的传热、传质特性进一步促进了脱硝反应。
Selective catalytic reduction (SCR) of De-NOx from synthetic flue gas with ammonia on iron-based (Fe2O3) particle catalyst was performed with a magnetically fluidized bed (MFB). The Fe2O3 catalyst was characterized by X-ray diffraction (XRD) and Brunauer-Emmett-Teller (BET) method. Results show that the efficiency of De-NOx gets to 90% at 180℃ and the scope of temperature with high efficiency of De-NOx is extended from 220-250℃ to 180-250℃ in magnetic fields of 0.01-0.015 T with MFB. The applied magnetic fields reduce apparent activation energies of SCR reaction, and improve the SCR activity of Fe2O3 catalyst at low temperatures. Influence of magnetic fields over SCR of De-NOx on Fe2O3 particle catalyst in MFB is concluded as follows: magnetic fields strengthen the magnetoadsorption of NO onto Fe2O3 surface, especially onto γ-Fe2O3 surface; NH2 and NO free radicals effects induced by the external magnetic fields increase the rate of SCR of NO on Fe2O3 catalyst; improved gas-solid contact and heat transfer characteristics further accelerate the reaction of De-NOx in MFB.