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

摘要

Selective catalytic reduction (SCR) of NO_x 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 NO_x 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 NO_x 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 NO_x removal efficiency in magnetically assisted fluidization.