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Author: search.filters.author.Arpornwichanop, AmornchaiSubject: search.filters.subject.Glycerol

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    Optimization of hydrogen production from three reforming approaches of glycerol via using supercritical water with in situ CO2 separation
    (2019-01-22)
    Patcharavorachot, Yaneeporn
    ;
    Chatrattanawet, Narissara
    ;
    Arpornwichanop, Amornchai
    ;
    Assabumrungrat, Suttichai
    A pathway for hydrogen production from supercritical water reforming of glycerol integrated with in situ CO<inf>2</inf> removal was proposed and analyzed. The thermodynamic analysis carried out by the minimizing Gibbs free energy method of three glycerol reforming processes for hydrogen production was investigated in terms of equilibrium compositions and energy consumption using AspenPlus™ simulator. The effect of operating condition, i.e., temperature, pressure, steam to glycerol (S/G) ratio, calcium oxide to glycerol (CaO/G) ratio, air to glycerol (A/G) ratio, and nickel oxide to glycerol (NiO/G) ratio on the hydrogen production was investigated. The optimum operating conditions under maximum H<inf>2</inf> production were predicted at 450 °C (only steam reforming), 400 °C (for autothermal reforming and chemical looping reforming), 240 atm, S/G ratio of 40, CaO/G ratio of 2.5, A/G ratio of 1 (for autothermal reforming), and NiO/G ratio of 1 (for chemical looping reforming). Compared to three reforming processes, the steam reforming obtained the highest hydrogen purity and yield. Moreover, it was found that only autothermal reforming and chemical looping reforming were possible to operate under the thermal self-sufficient condition, which the hydrogen purity of chemical looping reforming (92.14%) was higher than that of autothermal reforming (52.98%). Under both the maximum H<inf>2</inf> production and thermal self-sufficient conditions, the amount of CO was found below 50 ppm for all reforming processes.
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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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    Catalytic reforming of glycerol in supercritical water with nickel-based catalysts
    (2014-09-12)
    Pairojpiriyakul, Thirasak
    ;
    Croiset, Eric
    ;
    Kiatkittipong, Kunlanan
    ;
    Kiatkittipong, Worapon
    ;
    Arpornwichanop, Amornchai
    The catalytic performance of nickel catalysts supported on La <inf>2</inf>O<inf>3</inf>, α-Al<inf>2</inf>O<inf>3</inf>, γ-Al <inf>2</inf>O<inf>3</inf>, ZrO<inf>2</inf>, and YSZ for supercritical water reforming of glycerol was investigated. Experiments were conducted in a tubular reactor made of Inconel-625 with the temperature range of 723-848 K under a pressure of 25 MPa. Carbon formation causing operation failure was observed for α-Al<inf>2</inf>O<inf>3</inf>, γ-Al<inf>2</inf>O<inf>3</inf> and ZrO<inf>2</inf> at temperatures higher than 748, 798 and 823 K, respectively. Ni/La<inf>2</inf>O<inf>3</inf> exhibited the highest H<inf>2</inf> yield where almost complete conversion was obtained at 798 K. Moderate space velocities (WHSV = 6.45 h<sup>-1</sup>) and glycerol feed concentration (5wt.%) favor high hydrogen selectivity and yield. Methanation is favored at a low WHSV or high glycerol feed concentration, resulting in a lower H<inf>2</inf> yield. Increasing Ni loading on the Ni/La<inf>2</inf>O<inf>3</inf> catalyst strongly promoted the reforming, water-gas shift, and methanation reactions, which contributed significantly to the product species distribution. © 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.