Optimization of the methanol oxidation over iron-molybdate catalysts

The oxidation of methanol on industrial iron-molybdenum catalysts was investigated with a view to shed more light on the possibilities to optimize the process. Stainless steel pseudo-isothermal reactor, located in a precisely controlled thermostat was used to ensure conditions of the process as close as possible to the industrial. The catalytic activity was evaluated under steady state conditions and methanol conversion above 99.0% on the basis of the shape of the temperature profile in height of the catalyst layer, the situation of the "hot spot" and the temperature of the gas flow at exit of the catalyst layer. The outlet gas mixture was analyzed for CH2O, CH3OH, CO, dimethylether (DME), and CO2 content in the analytical section. The influence of the process parameters on the catalyst activity and selectivity was analyzed and it was concluded that oxygen concentration in the feed mixture has to be equal to or higher than the methanol concentration and water concentration in the range of 2.0-3.0% does favor the selectivity of the process. The increase of methanol concentration in the gas mixture fed in the reactor leads to a dramatic change both of the temperature profile of the catalyst layer and the distribution of the reaction products. A number of laboratory experiments were performed to clarify the influence of the most important parameters of the process (temperature, space velocity and methanol concentration) on the efficiency of the adiabatic layer. (C) 2009 Elsevier B.V. All rights reserved.