Simultaneous treatment of organic compounds, CO, and NOx in the incineration flue gas by three-way catalyst

The performance of a three-way catalyst (TWC) Pd/Rh/CeO2/Al2O3 which has the ability to simultaneously treat different pollutants in the incineration flue gas was studied. The catalyst support CeO2/Al2O3 was prepared by the modified oil-drop sol-gel process, and Pd/Rh was coated by the successive impregnation procedures. Catalytic experiments were carried out to study the destruction removal efficiency (DRE) of organic compounds benzene, toluene, ethylbenzene, xylene (BTEX), polycyclic aromatic hydrocarbons (PAHs), CO, and NOx at different operating conditions. The effects of heavy metals, acid gas, and water vapors on the characteristic and performance of TWC were also investigated. Experimental results showed that the DRE of BTEX, PAHs, CO, and NOx by one-stage TWC reactor was not good but was higher than 80% by two-stage TWC reactor. The best composition ratio of Pd/Rh catalyst in one-stage reactor was 1/0.15. The presence of heavy metals Pb, Cd and acid gas SOx, HCl in the flue gas poisoned the catalysts Pd and Rh in TWC. The effect of water vapor was slight and reversible. The structure characteristics of catalysts and the reactions of various pollutants with active catalyst were much related to the performance of TWC. (C) 2003 Elsevier B.V. All rights reserved.