Advanced oxidation of toluene using Ni-olivine catalysts: Part 2. Toluene oxidation kinetics and mechanism of Ni-olivine catalysts synthesized via electroless deposition and thermal impregnation.
The production of synthesis gas (syngas) involves the gasification of biomass under oxygen-limited conditions, which also produces tars. Tars pose significant problems for mechanical devices by depositing on piping, resulting in clogging and engine fouling. While recent research has shown that thermally impregnated Ni-olivine has been effective in reforming tars into H2 and CO, this technique possessed limited economic feasibility due to high input energy requirements. Thus, stable, active, and inexpensive catalysts are required for effective and efficient conditioning of syngas. This research compared the activity of Ni-olivine catalysts synthesized via electroless plating (ELP) (35°C) and thermal impregnation (TI) (1400°C) for oxiding toluene in a flow-through reactor. The objectives were to (1) determine the kinetics of toluene oxidation, (2) propose a reaction mechanism for toluene oxidation, and (3) investigate the effect of syngas on toluene oxidation. Conversion of toluene using Ni-olivine catalysts increased with increasing ozone concentration and temperature, as well as decreasing toluene molar flow rate, and facilitated the complete oxidation of toluene. The information obtained from this research is expected to provide opportunities for efficient cleanup of tars from biomass gasification facilities at lower temperatures.