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Material and Energy Balance of Methanol Feed 1 kW SOFC Power System
Tuesday, 7 October 2014: 17:40
Sunrise, 2nd Floor, Galactic Ballroom 4 (Moon Palace Resort)
K. L. Hsueh (National United University, Industrial Technology Research Institute), F. P. Ting (Hephase Energy Co. Ltd., Industrial Technology Research Institute), Y. C. Chang, J. L. Huang (Industrial Technology Research Institute), Y. T. Cheng (Taiwan Power Company), and W. S. Chang (Industrial Technology Research Institute)
High chemical to electric energy conversion efficiency and ease capture of carbon dioxide makes solid oxide fuel cell (SOFC) very attractive for distributed power generation using natural gas, syngas, biofuel, and methanol as the fuel. A 1 kW prototype power unit was built by ITRI/Hephase using methanol as the fuel. Fig.1 is the flow chart of 1 kW SOFC power unit. The methanol is converted into hydrogen by a reformer. Electric pre-heater is used to maintain the fuel stream temperature for reformer inlet and for SOFC anode inlet. Residue hydrogen in fuel cell exhaust is combusted in an afterburner. Heat produced from the afterburner is used to heat up the inlet air stream of SOFC. Photo of this unit is depicted on Fig. 2. “HotBox” is located at up-left portion. This unit contains afterburner, electric heater, and heat exchanger. Up-right portion is the SOFC stack. Bottom portion is the electric controller/monitor. This power unit was transferred to Taiwan Power company for long-term operation and testing.
A steady state material and energy balance was carried out throughout the entire SOFC system. The polarization curve and operating point used in the model calculation is depicted on Fig. 3. This curve was calculated from equation (1). The Vr, DVact, DVohm, DVconcare equilibrium cell voltage, voltage loss due to electrochemical reaction, voltage loss due to internal resistance, voltage loss due to concentration polarization.
Major heat fluxes among each components and temperature of each streams were calculated. Major efficiency losses were also identified. Typical result is given on Fig. 4. Experimental data were collected. This model and parameters used in the calculation will be adjusted to fit the measured result.
Authors wish to thank the financial support from BOE/MOEA (Bureau of Energy, Ministry of Economic Affairs) and NSC (National Science Council). This work was carried out by researchers under the collaboration among Hephas Energy, Industrial Technology Research Institute/Green Energy and Environment Research Laboratory, National United University, Dept. Energy Engineering, and Taiwan Power Company.
