Effect of fly ash on catalytic removal of gaseous dioxins over V2O5-WO3 catalyst of a sinter plant.
A PCDD/F(polychlorinated dibenzo-p-dioxin and dibenzofuran)-containing gas stream generating system was developed to investigate the efficiency and effectiveness of V2O5-WO3 catalyst for PCDD/F destruction. Catalytic decomposition of PCDD/Fs (simulated gas streams) was evaluated with lab-scale pelletized and plate-type catalyst based on V2O5-WO3/TiO2 at controlled temperature, space velocity, and inlet PCDD/F concentration. Due to the lower porosity of the pelletized catalyst PCDD/F destruction efficiencies reach 72.9-83.2% for different levels of inlet PCDD/F concentrations (1.08-3.04 ng-TEQ/Nm3) of the gas stream (space velocity: 5000 h(-1)). As the surface area is increased from 287 m2/m3 (plate-type A) to 550 m2/m3 (plate-type B), the PCDD/F destruction achieved with plate-type catalyst increases from 76.0% to 85.3% at 320 degrees C (space velocity: 5000 h(-1)). In addition, the results of pilot-scale experiment (real flue gases of a sinter plant) indicate that relatively lower PCDD/F destruction efficiencies (62.1-65.7%) were achieved with the plate-type B catalyst as the solid-phase PCDD/F and fly ash passed through the reactor (space velocity: 5000 h(-1)). Overall, the lab-scale and pilot-scale experiments indicate that PCDD/F destructions achieved with pelletized and plate-type catalysts strongly depend on the operating temperature of the catalyst. The results also indicate that the presence of fly ash the lowers PCDD/F destruction due to significant PCDD/F formation via de novo synthesis at 320 degrees C.
Graduate Institute of Environmental Engineering National Central University, Chungli 320, Taiwan.
Shu Hao
SH
Chang
Kai Hsien
KH
Chi
Chi Wei
CW
Young
Bao Zhen
BZ
Hong
Moo Been
MB
Chang
D000393:Air Pollutants / Q000737:chemistry; D002244:Carbon / Q000737:chemistry*; D002384:Catalysis; D060729:Coal Ash; D004147:Dioxins / Q000737:chemistry*; D007220:Industrial Waste; D010087:Oxides / Q000737:chemistry*; D052638:Particulate Matter / Q000737:chemistry*; D014414:Tungsten / Q000737:chemistry*; D017968:Vanadium Compounds / Q000737:chemistry*
D000393:Air Pollutants; D060729:Coal Ash; D004147:Dioxins; D007220:Industrial Waste; D010087:Oxides; D052638:Particulate Matter; D017968:Vanadium Compounds; D002244:Carbon; C511604:tungsten oxide; C066075:vanadium pentoxide; D014414:Tungsten