A. Gervasini et V. Ragaini, Catalytic technology assisted with ionization/ozonization phase for the abatement of volatile organic compounds, CATAL TODAY, 60(1-2), 2000, pp. 129-138
The catalytic combustion process of air-mixtures containing volatile organi
c compounds (VOCs)! associated with an ionization/ozonization reactor (IOCC
technique, ionization-ozonization-catalytic-combustion) has been utilized
for the abatement of two very toxic industrial VOCs: acrylonitrile (ACN) an
d vinyl chloride (VCM). The pre-catalytic effects (electric discharge plus
the action of ozone), the conventional and IOCC combustion tests were studi
ed. Two different catalysts were used: oxide catalyst, copper-chromite (Cu-
Cr), and Pt metal catalyst (0.5 wt.% Pt/gamma-Al2O3).
The abatement of ACN was markedly influenced by the pre-catalytic effects.
Starting from 3 kV, an increasing abatement of ACN was observed with the vo
ltage applied to the ionization reactor at any initial ACN concentration (5
00-1500 ppm). The ACN catalytic combustion, performed by the IOCC technique
, led to 91 and 98% yield of CO2 on Cu-Cr and Pt catalysts, respectively, a
t 260 degrees C. Complete absence of hazardous intermediates, such as hydro
gen cyanide, was observed.
The Cu-Cr catalyst, at 300 degrees C, was able to abate 57 and 23% of VCM a
t 10000 and 20000h(-1), respectively. IOCC combustion led to improved conve
rsion. At 200 degrees C and 3300 h(-1), 98% and only 49% of VCM abatement o
perating according to IOCC and classical combustion was obtained, respectiv
ely. The IOCC combustion runs, performed at different initial VCM concentra
tions (585 and 1170 ppm). indicated a superior abatement when low VCM conce
ntration was fed, at a given catalyst temperature and contact time. This in
dicated a marked influence of the pre-catalytic effects on the abatement. (
C) 2000 Elsevier Science B.V. All rights reserved.