Methanol-to-olefins technology creates another “on-purpose” path to propylene

Total Petrochemicals converted methanol to ethylene and propylene at its Feluy, Belgium complex, utilizing technology from Honeywell subsidiary UOP LLC (Des Plaines, IL), in a bid to show that feedstocks other than petroleum can be used to produce key plastics feedstocks. Since its start-up last year, the demonstration unit has run consistently for more than 150 days, successfully employing UOP's Hydro methanol-to-olefins (MTO) technology. Propylene, a key building block for commodity polymer polypropylene, is most typically derived from petroleum by-product, napththa. In a release, Peter Piotrowski, senior VP and general manager of UOP Process Technology and Equipment said the new technology could provide petrochemical producers new alternatives to petroleum by enabling the use of methanol that can be derived from sources like natural gas, coal, or biomass.

The demonstration plant integrates MTO technology with the Total Petrochemicals/UOP Olefin Cracking Process (OCP). Jointly developed by Total Petrochemicals and UOP, the OCP process reportedly boosts the total yield of usable ethylene and propylene, while minimizing hydrocarbon byproducts. The OCP unit is scheduled to start up later this year after initial testing of the MTO unit is completed. Total's Feluy site has total capacity exceeding 1.2 million tonnes/yr, with three polypropylene production lines accounting for 900,000 tonnes/yr of annual capacity.

The demonstration plant was designed to assess the technical feasibility of the integrated MTO and OCP processes on a semi-commercial industrial scale with full product recovery and purification. Total and UOP believe these combined technologies can provide the highest yields available for producing light olefins from methanol.

In an April 2005 presentation at the Asian Refining Technology Conference, UOP's Mark Houdek and James Andersen laid out the prospects for MTO technology, noting that at the time, most of the propylene consumed in the production of petrochemicals was produced as a byproduct of ethylene production. Given the ethylene capacity additions that are underway or pending, the authors posited that there would be less propylene produced per ton of ethylene from conventional ethylene plants due to a shift towards lighter cracker feedstocks. The pair proposed that the pending propylene shortfall be overcome through "on-purpose" propylene production. In addition to UOP's MTO process, there are a number of routes to "on-purpose" propylene where the chemical isn't simply created as a by-product of ethylene manufacture, including propane dehydrogenation, metathesis, and olefin cracking. At the time of the paper, Houdek and Andersen estimated that approximately two-thirds of propylene production supplied from thermal steam cracking of liquid feedstocks, primarily naphtha. —[email protected]