(153c) A Synopsis of the Production of Propylene Via Oxidative Dehydrogenation of Propane: How Far from Its Commercial Implementation?

Currently, propylene is the second most important olefin and its demand is growing faster than ethylene. Propylene is obtained in well-established industrial processes such as steam cracking of naphtha, and to a smaller extend, via conventional dehydrogenation of propane (PDH). The recent exploitation of methane- and ethane-rich shale gas in North America has caused a shift in the crackers feedstock to ethane instead of naphtha, resulting in the building of more ethane crackers which produce mainly ethylene and almost no propylene. As a consequence, on-purpose PDH technology is being employed increasingly to make propylene. However, PDH suffers inherent disadvantages (demands high reaction temperatures and below atmosphere pressure, expensive catalysts, catalyst regeneration, high capital cost) that make it economically viable only in cases where low-cost liquid-petroleum-gases (LPGs) are available. Despite of other on-purpose technologies (metathesis, methanol to olefins) gaining territory in the production and market of propylene, the oxidative dehydrogenation of propane (PODH) has been historically considered an attractive alternative route to produce propylene and bridge the production-and-demand gap. Nevertheless, PODH has still not emerged from the lab-scale to the industry due to the low propylene yields. In this presentation, I compile and discuss some of the most remarkable advances that have been achieved during last decades in PODH with an emphasis on the catalysts structure-activity/selectivity relationship as well as the reaction mechanism.