Journal of Power Sources, Vol.243, 381-391, 2013
Polymer electrolyte membrane fuel cell grade hydrogen production by methanol steam reforming: A comparative multiple reactor modeling study
Analysis of a fuel processor based on methanol steam reforming has been carried out to produce fuel cell grade H-2. Six reactor configurations namely FBR1 (fixed bed reactor), MR1 (H-2 selective membrane reactor with one reaction tube), MR2 (H-2 selective membrane reactor with two reaction tubes), FBR2 (FBR1 + preferential CO oxidation (PROX) reactor), MR3 (MR1 + PROX), and MR4 (MR2 + PROX) are evaluated by simulation to identify the suitable processing scheme. The yield of H-2 is significantly affected by H-2 selective membrane, residence time, temperature, and pressure conditions at complete methanol conversion. The enhancement in residence time in MR2 by using two identical reaction tubes provides H-2 yield of 2.96 with 91.25 mol% recovery at steam/methanol ratio of 1.5, pressure of 2 bar and 560 K temperature. The exit retentate gases from MR2 are further treated in PROX reactor of MR4 to reduce CO concentration to 4.1 ppm to ensure the safe discharge to the environment. The risk of carbon deposition on reforming catalyst is highly reduced in MR4, and MR4 reactor configuration generates 7.4 NL min(-1) of CO free H-2 from 0.12 mol min(-1) of methanol which can provide 470W PEMFC feedstock requirement. Hence, process scheme in MR4 provides a compact and innovative fuel cell grade H-2 generating unit. (C) 2013 Elsevier B.V. All rights reserved.