Factors controlling the sintering of an industrial bimetallic reforming catalyst during regeneration

Abstract

The effect of parameters such as temperature, gas flow rate, oxygen concentration and oxychlorination on the sintering of an industrial bimetallic reforming catalyst (Pt-Ir/μ.Al 2O 3) during regeneration were investigated. The time taken for carbon removal decreased with increasing gas flow rate from 0.75 to 3 l/h/cc. cat. and good metal dispersion and high BET surface area were achieved at a flow rate of 3 l/h/cc.cat. Increasing the initial combustion temperature from 370 to 450° C led to considerable sintering of the metal. However, it did not significantly change the BET surface area. Better metal dispersion and higher BET surface area were restored using oxygen concentrations in the range 0.3 to 0.6% above which value considerable sintering of both metal and support occurred. In sintered catalysts, metal redispersion could be improved to some extent by oxychlorination treatment. Dispersion of the metallic phase was found to be higher at higher chlorine levels in the catalyst.