Processing and Conversion
The strategic goal of Conversion Research and Development (R&D) is to develop technologies for converting feedstocks into commercially viable liquid transportation fuels, as well as bioproducts and biopower. The diversity of the biomass resource requires the development of multiple conversion technologies that can efficiently deal with the broad range of feedstock materials, as well as their physical and chemical characteristics. The Office splits its Conversion R&D efforts into two areas: Biochemical Conversion R&D and Thermochemical Conversion R&D. Within each area, there are many possible variations, but the main differences in processing have to do with the temperatures used to deconstruct the biomass, the biomass derived intermediates produced from deconstruction, and the catalytic means used to upgrade those intermediates to finished fuels and products.
While Conversion R&D needs are addressed through two separate technology areas—Biochemical and Thermochemical—the Office envisions that the combined use of technologies from both areas (hybrid processing) will also offer a tremendous opportunity for optimizing the conversion of biomass into a variety of different fuels, chemicals, and energy products.
Biochemical Conversion – In a traditional biochemical conversion process, biomass is chemically pretreated and fed to enzymes that liberate the biomass derived sugars. In turn, the resulting sugar-rich stream (hydrolyzate) is fed to organisms that ferment the sugars to fuel precursor molecules.
The biochemical conversion platform also has a large stake in some low-temperature, non-enzymatic, and non-biological processing routes. Such technology pathways use catalytic and mechanical systems to both produce sugars (and/or other intermediates from biomass) and upgrade those sugars and intermediates to create finished fuel blendstocks.
Thermochemical Conversion – In most thermochemical conversion processes, biomass is rapidly heated to temperatures between 400–900°C in the absence of oxygen—and sometimes in the presence of catalyst—to produce either a gaseous or liquid (oil-like) intermediate. These intermediates are then catalytically upgraded to fuel blend quality oxygenates and hydrocarbons.