Characteristics of Pd-Rh/CeO2/Al2O3 TWC for NOx and PAHs removal in flue gas of MSWI

Pd-Rh/CeO2/Al2O3 three-way catalysts by sol-gel method were investigated by catalytic performance test for simultaneous removals NOx and PAHs. The experiments were carried out in a laboratory scale incineration system equipped with a catalyst reactor. The catalysts were characterized with BET, SEM, and XRD. The sol-gel way prepared carrier CeO2/Al2O3, characterization results showed that, CeO2/Al2O3 the specific surface area is 207m²/g, average pore size is 88.76 Å, pores volume is 0.67 cm³/g. In addition to surface roughness, the surface also appeared in many small crystal particles, suggesting that these small crystals may be Pd crystals. Experimental results showed that the removal efficiency of NOx, and PAHs in Pd-Rh/CeO2/Al2O3 TWC was generally greater than 80%. The bimetallic catalyst with a Pd/Rh ratio of 1/0.10 was found to have a best activity for highest removal efficiency.

I. Introduction

Incineration is the effective and prevailing method for waste disposal in China. The treatment of MSW has become an important environmental issue of global concern. With ever more stringent emission regulations being enforced by the environmental governing bodies with regards the emissions from municipal solid waste incinerator (MSWI), flue gas aftertreatment is now a necessary component in the emissions reduction strategy. NO_x is also a major pollutant in the flue gas of various incineration processes. Polycyclic aromatic hydrocarbons (PAHs) are a major hazardous organic pollutant in the flue gas of municipal solid waste incinerators (MSWI). Removal of PAHs and NO_x from the flue gas of MSW incineration processes has become a challenging task.