(562d) Cartridge-Based Ceramic Microreactor Networks for Process Intensification in Fuels Reforming: Demonstration and Modeling of Complex 2-D Thermal Integration

Increasing concern with atmospheric pollution and difficulties associated with nuclear power have caused a surge of interest in using fuels cells as a means of electrical power generation for utility power and also for electrical vehicles^[1]. With the difficulty of storing hydrogen, efficient microreformers are developed to convert hydrocarbon fuels into hydrogen on-site for utilization by proton-exchange membrane (PEM) or solid-oxide fuel cells (SOFC's) in portable electronics devices and automotive applications. Methanol has been identified as an attractive fuel to produce hydrogen because of its high hydrogen-to-carbon ratio and lower inter-carbon bonds which therefore can be reformed efficiently at moderate temperatures ^[2]. Thermally integrated microchannel reactors have been intensively studied as a power technology for realizing all-in-one portable reformers capable of autothermal hydrogen generation via combinations of two or more chemical processes in a compact unit ^[4].

Our research group has previously demonstrated a new cost-effective approach for realizing heat integrated ceramic microchannel networks capable of coupling several unique chemical processes in complex two-dimensional radial distribution patterns over a broad range of scale without loss in design flexibility ^[3]. This technique presents the following advantages; (i) ease of catalyst packing, (ii) higher conversion and yield with less amount of catalyst, (iii) increase in Overall hydrogen yield and thermal efficiency, (iv) location of hotspot at the center of the reactor axial length and (v) external insulation to the microchannel reactor resulted in a limited amount of radial heat losses to ambient.

This work presents the design of a ceramic microchannel network, interfaced with brass distributors in order to evaluate the thermal integration issues of a new class of versatile, scalable, integrated ceramic microchannel network. Detail thermal and reaction experiments are performed varying the flowrates of the reaction streams and varying the configuration of catalyst packing in order to find the optimum operating parameters to achieve substantial gain in overall hydrogen yield using this compact, cost-effective, and cartridge based reformer. Experimental results are compared with detailed 3-D COMSOL simulations to demonstrate the ability to flexibly design unique and/or non-intuitive thermal integration schemes.

¹J.C.Amphlett,K.A.M.Creber,J.M.Davis,R.F.Mann,B.A.Peppley and D.M.Stokes,  “Hydrogen Production by Steam Reforming of Methanol for Polymer Electrolyte Fuel Cells”,Int.J.Hydrogen Energy., 1994, 19, pg 131-137.

²Jeong-Se-Suh, Ming-tsang Lee, R.Greif, C.P.GrigoropoulosHan,”A study of steam methanol reforming in a microreactor”, J. Power Sources. 2007, 173, pg 458-466.

³Angela Moreno, Benjamin A.Wilhite, “Autothermal hydrogen generation from methanol in a ceramic microchannel network”, J. Power Sources., 2010, 195,pg 1964-1970.

⁴A.Moreno,S.Damodharan and B.A.Wilhite, “Influence of Two-Dimensional Distribution schemes upon Reactor Performance in a Ceramic Microchannel Network for Autothermal Methanol Reforming”, Ind. Eng. Chem. Res.,2010,49(21),pg 10956-10964.