The
study of toluene conversion, in a gas such as the one obtained
during the pyrolysis of biomass, was conducted at atmospheric pressure
in homogeneous and in coupled plasma-catalytic systems. The effects
of discharge power, initial concentration of toluene, and the presence
of the bed of NiO/Al2O3 - G-0117 (industrial
catalyst for methane water shift) on the conversion of C7H8, the composition of the outlet gas, and its calorific
value have been investigated. The gas flow rate was 1000 Nl/h and
the initial gas composition was CO (0.13), CO2 (0.12),
H2 (0.25), and N2 (0.5). The initial toluene
concentration was in the range of 2000–4000 ppm. The obtained
results show that the conversion of toluene increases with discharge
power and the highest one was obtained in the coupled plasma-catalytic
system. It was higher than that in the homogeneous system of gliding
discharge plasma. The composition of gas changed within the range
of a few percent. In the outlet gas acetylene, ethylene and ethane
were observed. Trace amounts of toluene were reduced to benzene and
formed C3 and C4 hydrocarbons. In an extended process, the reduction
of NiO to metallic nickel, methanation reaction of carbon oxides,
and an increase of the conversion of toluene were observed. The conversion
of toluene in the extended process was 92%. The catalytic activity
of G-0117 in a coupled system increased during the study conducted
for about 40 min. The use of G-0117 catalyst led to an increase in
the calorific value of the outlet gas. In every examined system, it
was above the minimal level demanded by engines and turbines. After
the process, carbon deposits were present.