FORMALDEHYDE PRODUCTION FROM METHANOL USING A POROUS VYCOR GLASS MEMBRANE REACTOR

The feasibility of using a membrane reactor to shift the equilibrium of formaldehyde production from methanol is investigated. Formaldehyde production from methanol over a silver catalyst is an endothermic, reversible, and conversion-limited dehydrogenation reaction. In the membrane reactor, the equilibrium is further shifted by removing the hydrogen through the membrane. This enables the membrane reactor to be operated economically at a lower temperature. The permeabilities are measured using a porous Vycor glass membrane. The reaction kinetics are investigated over the temperature range of 300-400-degrees-C at atmospheric pressure in a fixed-bed differential reactor over 99.998% silver needle catalyst. The membrane reactor performance is experimentally analyzed at atmospheric pressure to study the effect of changing operating variables such as temperature, space velocity, air/methanol feed ratio, and membrane surface area. A theoretical model is derived and a computer simulation is carried out based on the Runge-Kutta method to verify the above experimental data. Using an isothermal cocurrent model, a parametric study is conducted to provide basic information regarding scale-up and optimum operating conditions. The experimental study and parametric analysis of the present study point to the necessity of developing an improved permselective inorganic membrane material. Such a new membrane will make the membrane reactor method an attractive alternative in many industrial applications.