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    Hydrogen and power generation from supercritical water reforming of glycerol and pressurized SOFC integrated system: Use of different CO2 adsorption process
    (2018-09-13)
    Patcharavorachot, Yaneeporn
    ;
    Saebea, Dang
    ;
    Authayanun, Suthida
    ;
    Arpornwichanop, Amornchai
    The performance analysis of an integrated system of glycerol supercritical water reforming and pressurized SOFC was presented. The use of different CO<inf>2</inf> adsorption processes that include in situ and ex situ processes was compared to determine the suitable process for hydrogen and power generations. The influence of operating condition, e.g., temperature and pressure of reformer, supercritical water to glycerol (S/G) molar ratio, and calcium oxide to glycerol (CaO/G) molar ratio was examined. Then, the electrical performance of each integrated process was considered with respect to the SOFC conditions comprising temperature, pressure, and current density. The simulation results revealed that both processes have same favourable conditions for temperature and pressure operated at 800 °C and 240 atm, respectively. The suitable S/G and CaO/G molar ratios for in situ process are 10 and 2 whereas those for ex situ process are 20 and 1. Under these conditions, maximum hydrogen can be achieved as 87% and 75% for in situ and ex situ processes, respectively. When both integrated processes are operated at the optimal SOFC conditions as 900 °C, 4 atm, and current density of 10,000 A/m<sup>2</sup>, the SOFC efficiency of 71.56% and 62.12% can provide for in situ and ex situ processes, respectively.
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    Item type:Publication,
    Performance and environmental study of a biogas-fuelled solid oxide fuel cell with different reforming approaches
    (2018-03-01)
    Chatrattanawet, Narissara
    ;
    Saebea, Dang
    ;
    Authayanun, Suthida
    ;
    Arpornwichanop, Amornchai
    ;
    Patcharavorachot, Yaneeporn
    In this work, solid oxide fuel cells (SOFCs) using biogas as the fuel with two different reforming approaches, i.e., external and internal reforming, were studied to determine the optimal operation conditions for each approach. Thermodynamic analysis was performed using a flowsheet simulator. The equilibrium gas composition was calculated by minimizing the Gibbs free energy. An electrochemical model that includes three voltage losses (i.e., activation, ohmic, and concentration losses) was used to predict the performance of the SOFCs. The simulation results showed that the reformer in the external reforming SOFC should be operated at a temperature of 973 K, a pressure of 1 atm, and a steam-to-carbon molar ratio of 0.5. In performance analysis, the simulation results indicated that both approaches have the same optimal operating conditions, i.e. a temperature of 1173 K, a pressure of 3 atm, and a current density of 5000 A/m<sup>2</sup>. Under the same operating conditions, the internal reforming SOFC exhibited better electrical efficiency than that of the external reforming SOFC. Considering the CO<inf>2</inf> and CO emissions, the exhaust gas obtained from the anode side of the internal reforming SOFC contained 7.4% CO<inf>2</inf> and 37.9% CO, which are higher values than those for the external reforming SOFC (1.9% CO<inf>2</inf> and 32.5% CO).
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    Item type:Publication,
    Effect of different fuel options on performance of high-temperature PEMFC (proton exchange membrane fuel cell) systems
    (2014-04-15)
    Authayanun, Suthida
    ;
    Saebea, Dang
    ;
    Patcharavorachot, Yaneeporn
    ;
    Arpornwichanop, Amornchai
    High-temperature proton exchange membrane fuel cells (HT-PEMFCs) have received substantial attention due to their high CO (carbon monoxide) tolerance and simplified water management. The hydrogen and CO fractions affect the HT-PEMFC performance and different fuel sources for hydrogen production result in different product gas compositions. Therefore, the aim of this study is to investigate the theoretical performance of HT-PEMFCs fueled by the reformate gas derived from various fuel options (i.e., methane, methanol, ethanol, and glycerol). Effects of fuel types and CO poisoning on the HT-PEMFC performance are analyzed. Furthermore, the necessity of a water-gas shift (WGS) reactor as a CO removal unit for pretreating the reformate gas is investigated for each fuel type. The methane steam reforming shows the highest possibility of CO formation, whereas the methanol steam reforming produces the lowest quantity of CO in the reformate gas. The methane fuel processing gives the maximum fraction of hydrogen (≈0.79) when the WGS reactor is included. The most suitable fuel is the one with the lowest CO poisoning effect and the maximum fuel cell performance. It is found that the HT-PEMFC system fueled by methanol without the WGS reactor and methane with WGS reactor shows the highest system efficiency (≈50%). © 2014 Elsevier Ltd.