If the 110 facilities in the U.S. capable of fluid catalytic cracking — a conversion process used in petroleum refineries — were used to simultaneously produce biomass-derived fuel intermediates, the result could be more than 8 billion gallons of bio-derived fuels without the need to build separate biorefineries.

The technology to achieve this goal was recently demonstrated by the Energy Department’s National Renewable Energy Laboratory (NREL) in collaboration with petroleum refining technologies supplier W.R. Grace and plant designer Zeton Inc.

Pilot-scale test model. Image source: NRELA pilot-scale facility was built that can co-produce biomass-derived fuel intermediates with existing petroleum refinery infrastructure. The project combines biomass pyrolysis with fluid catalytic cracking to demonstrate the potential to co-process biomass-derived streams with petroleum at an industrially relevant pilot scale.

At the front end of this NREL-designed systemi, fast pyrolysis liquefies the biomass by rapid heating to 400°C–600°C in the absence of oxygen. That is followed by cooling the resulting vapors into a liquid bio-oil.

But the resulting liquid product is acidic, chemically unstable, and contains more oxygenated compounds than petroleum crude oils. A separate W.R. Grace-designed reactor unit catalytically reduces the oxygen content before condensation of the vapors occurs. This both stabilizes the liquid and minimizes downstream processing challenges, as the product can then be finished into a conventional fuel blend stock at an existing petroleum refinery. Co-processing verification experiments with biomass-derived vapor and petroleum demonstrated that biomass components were integrated into the liquid gasoline product.

Based in NREL's Vapor Phase Upgrading Laboratory, the pilot plant enables a range of experimental conditions for continued catalyst evaluation, to improve the quality and yield of the bio-oil intermediate. Data generated from these tests will be available to inform future refinery integration efforts. The pilot equipment will also be made available for private companies to test related materials and processes, so that they can avoid the time and expense of building their own pilot plants—which will facilitate commercial-scale co-production of biomass- and petroleum-derived products.