Experimental Research of NOx Removal by NH_3 on Admixtures of Iron Ore and Iron Catalyst in a Magnetically Fluidized Bed

摘要

Selective catalytic reduction (SCR) of NOx from simulated flue gas by ammonia (NH_3) using admixtures of iron ore and iron catalyst in a magnetically fluidized bed has been experimentally studied. We conclude the following from the experimental research. First, iron ore has a good catalytic effect on NOx removal; The removal efficiency with iron ore can reach 80% at 200°C without the effects of magnetic fields. XRD spectra indicate that the main component of iron ore in the experiments is α-Fe_2O_3. However, iron ore is not sensitive to magnetic field because of its anti-ferromagnetic property. With the aid of ferro-magnetic iron, the mixture of iron and iron ore displays a wide magnetically stabilized fluidization region at external axial magnetic fields of 0.005T. Hence, while the removal efficiency of NOx almost does not change with iron ore as catalyst under magnetic fields, it can be greatly improved by the aid of magnetic field using a mixture of iron ore and iron as catalyst; in particular at 0.005T, the removal efficiency reaches up to 90% at 300°C, which is 16% more compared with that without the effects of magnetic fields. The results indicate that admixtures of iron ore and iron catalyst manifest almost perfect NOx removal efficiency in magnetically assisted fluidization.