BTG was developed to meet the challenges posed by the reality of global markets. From the start, it was conceived to be a low-cost, highly efficient process that combines proven commercial reactions with new, environmentally benign catalysts and chemistry. Recognizing the importance of speed, efficiency, and simplicity, BTG applies a series of moderate-temperature, catalyzed reactions to convert lignocellulosic biomass into gasoline-range alcohols.
Converting biomass to fuels begins by breaking down the large, polymeric structures of hemicellulose and cellulose into smaller molecules that are more easily processed. Many attempts to deconstruct biomass using moderate-temperature chemistry, however, have been thwarted by a simple chemical fact: the products of depolymerization are more reactive than the starting biomass. Consequently, these techniques are usually non-selective and continue past the desired product (sugar) to undesirable compounds like organic acids and insoluble furan-based polymers.
BTG overcomes this limitation by chemically stabilizing the biomass deconstruction products to prevent them from reacting further. The stabilized products are not susceptible to further dehydration and are preserved in high yield. This unique approach greatly enhances selectivity in an energy-efficient way.
The stabilized products then undergo a final processing step that converts them into BioGasoline. This step reduces the oxygen content of the biofuel in order to increase the energy density and gasoline-compatibility of the product fuel by selectively adding hydrogen. This final processing step uses a breakthrough catalyst developed by Exelus that achieves the conversion rapidly and at high selectivity, without generating low-value light alkanes like methane or ethane. The product is a high-octane blend of gasoline-compatible alcohols that out-performs conventional fuel ethanol.
The BTG process scheme consists of three steps: liquid-phase decomposition of a biomass slurry with lignin rejection, stabilization in a fixed bed reactor, and deoxygenation in another fixed bed reactor. The finished Biogasoline is then separated from the water, which can be recycled.