(258e) Electrochemical Hydrogenation of Bio-Oil Compounds Using a Polymer Electrolyte Membrane Reactor

Electrochemical hydrogenation (ECH) is an option for stabilizing or upgrading bio-oil that employs mild conditions (less than 80ºC and ambient pressure). In this study, acetone, furfural and phenol are chosen as model substrates because of their abundance in bio-oil. The ECH method in a Polymer Electrolyte Membrane Fuel Cell (PEMFC) reactor has been considered to be one of the feasible ways of hydrogenating chemical compounds. In this study, acetone, furfural, and phenol which are present in pyrolysis bio-oil were studied for ECH. The main products from the ECH of acetone were isopropanol with selectivity approximately 90%. Diisopropyl ether was a byproduct. 16% propanol and 1% diisopropyl was identified in the final product using a new membrane, a holed bag collection method, the reaction temperature 65ºC, and the reaction relative humidity of 90%. Propanol selectivity could be further improved by reducing the input power supply voltage.

The main challenge in ECH using a proton exchange membrane reactor is that a large fraction of current goes towards generating hydrogen gas that is not used in the hydrogenation reaction. High current efficiency (59.7%) could be achieved by using a PEMFC reactor. The mild operation condition is the greatest advantage of the proposed method, the optimized reaction condition is at 65 ºC and 1 atmosphere. Relative humidity positively effects H₂­ Utilization Efficiency and Current Efficiency, while temperature did not show linear influence during acetone ECH. The challenging part was the membrane contamination. Suitable reaction pressure, low reaction temperature, and low reaction relative humidity could prolong membrane life.