Biorefinery integrates processes that produce chemicals, fuels, power and heat from biomass by thermochemical routes including gasification, pyrolysis and catalytic routes, or by biotechnical routes such as fermentation. Biomass-based fast pyrolysis and Fischer-Tropsch reactions have been extensively studied as promising processes for fuel and chemical production from renewable biomass(Figure 1). In spite of the sustainable character of these technologies, the target products are accompanied by large water fractions with organic residues considered as waste streams. The organic compounds included in those water fractions are contaminants and harmful substances for the environment. The disposal of those compounds reduces the efficiency of the processes, due to costly conditioning treatments in addition to upgradeable-product loss. In order to increase the product efficiency, the value of all streams should be maximized.
Currently, there is no efficient technology able to convert the diluted organic compounds in the water fractions of fast pyrolysis and Fischer-Tropsch processes. Catalytic aqueous-phase reforming (APR) of organic compounds is a highly potential route to obtain H2 and CH4 from these water fractions. However, intrinsic challenges of the process, such as mass transfer limitations and low concentrations of the reactants, as well as performance and stability of catalysts require significant research effort.
Text: Juha Lehtonen