Fluidized bed plasmas reactor for catalyst Synthesis and pretreatment. Application for Pollution Abatement in stationary and mobile sources

摘要

The preparation of automotive catalysts and commercial oxidation catalysts in stationary sources use a large amount of noble metal precursors. Moreover, during their preparation high energy (gas and temperature) is necessary for treatment processes. In order to develop a higher sustainable process, the plasma-assisted catalysts synthesis could be a solution. The use of plasmas for catalysis is already well developed and plasma treatment was already used in a low pressure system to replace the thermal calcination steps of the catalysts. Fluidized bed reactors offer the possibility to lead to homogenous treatment and have the additional advantage of excellent heat transfer rates between the gas and the particles, so that it can modify the catalytic properties of the prepared materials. The aim of our work is to prepare plasma-assisted catalysts dedicated to pollution abatement in stationary or mobile sources. For stationary sources, the first prepared catalysts are palladium based catalysts, which were chosen since the main reducing agent in combine heat power is methane. In the case of mobile sources, we have worked with silver based catalysts since ethanol could be chosen as a sustainable alternative reducing agent to replace ammonia. After the preparation of the different catalysts, the low fluidized bed plasma reactor was used to modify Pd/ y-alumina and Ag/y-alumina catalysts. A comparison with "classical calcination" in air at 500°C was performed in order to show the advantages of plasma treatments. The first catalytic results show that plasma treated catalysts lead to higher pollutant abatement than classically prepared ones. Thus, concerning the plasma process, we have studied the role of the plasma treatment time as well as the nature of the gas treatment. The characterization of the catalysts is in course in order to understand the influence of plasma treatment parameters on catalytic results.