Studies on Hydrogen production via Bio butanol Reforming for SOFC and PEMFC Applications

Abstract

The depletion of conventional fossil-based oil resources, continuous increase in energy demand, and emission of green-house gases due to the use of conventional energy sources demands for alternative, green and renewable energy source. H2 will be the possible solution for the upcoming energy crisis, as the combustion of H2 only leads to the production of water vapor and can also be efficiently utilized in fuel cells. But due to storage and transportation problems of H2, on-board production from renewable energy sources via catalytic reforming process seems a sustainable solution. In the current study, thermodynamic analysis of various bio-butanol reforming processes (steam reforming (SR), auto-thermal reforming (ATR), and sorption enhanced steam reforming (SESR)) is carried out. The effect of reformer operating conditions, i.e., temperature, pressure, steam to carbon molar ratio, oxygen to carbon molar ratio, and CaO to carbon molar ratio, on the yield of reformat gases and coke formation are studied in detail. Based on H2 production, favorable reformer conditions are proposed. Moreover, reforming processes are also compared in terms of their H2 production capabilities. SESR process found to produce high purity hydrogen (98.95%) followed by SR (70.65%) and ATR (28.24%) processes. Reforming processes were integrated with solid oxide fuel cell (SOFC) and low-temperature proton exchange membrane fuel cell (LT-PEMFC) systems. Reformer operating conditions were fixed as decided from the thermodynamic analysis, whereas fuel cell operating conditions, i.e., fuel utilization and operating temperature, were decided based on parametric variation study. As SOFC produces useful heat and electrical power, the performance of SOFC integrated reforming processes was evaluated in terms of electrical power generation, useful heat generation, heating utility requirements, electrical efficiency, thermal efficiency, and overall system efficiency. SOFC integrated with the ATR process displayed the highest overall system ef