(578g) Over 90% Ultra Pure H2 Yield at Liter Per Minute Level Flows by Ethanol Fuel Processing Demonstrated by Completing Wgs Reaction in a Compact and Robust Micro-Channel Catalytic Membrane Reactor

Considerable attention has been given in recent years to the development of integrated liquid hydrocarbon fuel processors due to their importance in on-demand H2 generation and distributed power generation systems. Using ethanol as the liquid fuel is an attractive option that is reported extensively in the literature. Large scale deployment of ethanol fuel processors has been hindered by low yield of H2 and/or recovery from reformate, inability to separate H2 to the requisite purity for long hours of operation, coking of catalyst, thermal integration issues among others. P&E developed an integrated ethanol fuel processor with a fuel utilization (H2 yield) greater than 90% for a continuous high purity H2 flow of more than 0.5 SLPM with impurities at the ppb level. Multiple reformer configurations have been tested including a micro-channel design for which thermal integration studies are carried out. Catalytic steam reforming of ethanol is carried out in Rh/CeO2 at more than 600 oC. A P&E compact and robust Pd alloy micro-channel membrane separator is used to separate H2 with yield up to 95% and purity levels of the order of ppb levels. The performance of fuel processing system including balance of plant components has been analyzed for a range of operating parameters such as temperature, pressure and space velocities. The feed into the integrated vaporizer-reformer consists of a dynamically variable ethanol-water mixture. The effluent gases are passed through a condenser and the condensables are separated in a knock out pot. The pressure in the reformer and the retentate side of the membrane separator are maintained by a back pressure regulator. The pure H2 flow from membrane separator varies from 0.5 - 1.6 SLPM for space velocities of the order of 1000-5000 hr-1. The H2 yield of the fuel processor significantly exceeds that which would have been obtained with an equilibrium composition reformate. This indicates that the in-situ removal of H2 in the presence of the Pd based membrane shifts the WGS equilibrium towards the right and to near completion. This ensures higher H2 yield as well as lower CO in the reformate stream. A feed of 1 ml/min of liquid ethanol fuel gives an ultra pure H2 flow of 1.2 SLPM with a H2 yield of 60%. A feed of 0.24ml/min ethanol gives more than 0.500 SLPM of pure H2 with a yield of more than 92% H2. Further studies on thermal integration and optimization using novel reformer configurations are in progress and will be discussed.