The study of alcohol induced hydrogen permeation in a catalytic membrane reactor

We have studied dehydrogenation and subsequent permeation of hydrogen from some small alcohols and hydrocarbons over a 20 μm thin Pd membrane at temperatures between 523 and 623 K. It is only for the smaller alcohols that significant amounts of hydrogen permeate the membrane. An addition of oxygen in the alcohol supply is needed to prevent a slow quenching of the permeation. The ratio of oxygen to alcohol is critical. For the right balance between methanol and oxygen permeation is very effective, and comparable to permeation caused by pure hydrogen. Studies of CH3OD and C2H5OD further show that the permeation is dependent on the hydrogen origin, i.e. the methyl and hydroxyl hydrogen have different reaction pathways and permeation probabilities.