Wen-Tang Hong

Experimental investigation into performance of integrated hotbox in 1-kW solid oxide fuel cell system

ABSTRACT An experimental investigation is performed to evaluate the performance of an integrated hotbox in a 1-kW solid oxide fuel cell (SOFC) system fed by natural gas. The integrated hotbox comprises all the main balance of plant components of an SOFC system, i.e. afterburner, reformer, and heat exchanger, and it not only reduces the physical size of the system but also yields improved system efficiency. The experimental results show that under optimal operating conditions, the combined H2 and CO content of the reformate gas is approximately 70%, while both anode and cathode in-gas temperatures are around approximately 750°C.

System Validation Tests for an SOFC Power System at INER

This research presents the results of system validation tests for an SOFC power system. In the study, the system was heated up without electric device, i.e., the fuel providing the required thermal energy through an integrated BOP (balance of plant). The ex-situ experiments, without an SOFC stack installed in the system, were first conducted to investigate the operability of a BOP apparatus. It was found that the BOP possessed high conversion rates for both steam reforming and water gas shift reactions. The total fuel concentration of hydrogen and carbon monoxide from the reformer was around 91.2%. The system validation tests showed that, with the natural gas as fuel, the output power from the stack reached to 1,060 W, while the fuel utilization efficiency and electrical efficiency were 67.16% and 45.0%, respectively. A steady 600-hour system operation test was carried out at an average system temperature of 694 C. Of which, a 36-cell stack was employed for the test. Meanwhile, the current, voltage and output power were 26 A, 32.3 V and 840 W, respectively, and its electrical efficiency was around 33.4%.

An Experimental Investigation into the Performance of a Novel-Integrated Afterburner-Reformer in a 1 kw Solid Oxide Fuel Cell System

In traditional Solid Oxide Fuel Cell (SOFC) systems, the anode and cathode off-gases are combusted in an afterburner and the flue gas is then used to provide the thermal energy required for hydrogen reforming. However, significant heat losses occur in the piping between the afterburner and the reformer, and thus the overall efficiency of the SOFC system is reduced. Accordingly, the present study proposes a novel-integrated afterburner-reformer, which not only improves the system efficiency, but also reduces the required afterburner operating temperature. The experimental results show that the combined H2 and CO content of the reformate gas is approximately 80%. In other words, the reforming performance of the proposed afterburner-reformer is comparable with that of a conventional electrically-heated reformer.

Experimental Investigation of 1 kW Solid Oxide Fuel Cell System with Hydrogen Fed Fuel and an Exhaust gas Burner

Compared to other fuel cell types, solid oxide fuel cell (SOFC) have a number of attractive features: fuel flexibility, components that are all solid state, no water management issues, and high quality surplus heat for combined heat and power (CHP). The aim of this paper is to investigate the optimal operation condition of porous media burner (so called after-burner) in a SOFC power system. The functions of after-burner are to increase the thermal efficiency and to decrease the harmful emissions of anode off gas for the SOFC operation. In order to find the optimal operation condition of after-burner, the experimental investigation of after-burner control logic is needed. The key manipulation parameters and the optimal after-burner operation conditions are presented in this paper. The experimental results show that the optimal after-burner operation is obtained when using an anode off-gas temperature of 650°C, a cathode off-gas temperature of 330°C, a flame barrier temperature of 700°C, an excess air ratio of 2 and a fuel utilization of U(subscript f) =0.6. Finally no extra fuel and additional cooling air are fulfilled under the long term operation of SOFC system and the simulations from burner ignition to SOFC long term operation period are also conducted.

Design and Performance Analysis of a Solid Oxide Fuel Cell/Gas Turbine (SOFC/GT) Hybrid System Used in Combined Cooling Heating and Power System

With high efficiency and very low emissions, fuel cells have been one of the choices of research in current energy development. The Solid Oxide Fuel Cell (SOFC) is a high temperature type fuel cell. It has the characteristic of very high operating temperature 1,027°C (1,300K). The SOFC has the main advantage of very high performance efficiency (over 50%), but also has very high exhaust temperature. Current studies point out that the combination of SOFC and Gas Turbine (GT) can produce efficiency more than 60%. The exhaust temperature of this hybrid power system can be as high as 227–327°C (500–600K). With this waste heat utilized, we can further improve the overall efficiency of the system. A simulation program of SOFC/GT system and the introduction of the concept of Combined Cooling, Heating, and Power System (CCHP) have been used in this study. The waste heat of SOFC/GT hybrid power generation system was used as the heat source to drive an Absorption Refrigeration System (ARS) for cooling. This waste heat enables the SOFC/GT to generate electricity in the system while providing additional cooling and heating capacity. Therefore, we have a combined CCHP system developed using three major modules which are SOFC, GT, and ARS modules. The SOFC module was verified by our test data. The GT and SOFC/GT modules were compared to a commercial code and literature data. Both the single- and double-effect ARS modules were verified with available literature results. Finally, the CCHP analysis simulation system, which combines SOFC, GT, and ARS, has been completed. With this CCHP configuration system, the fuel usability of the system by our definition could be above 100%, especially for the double effect ARS. This analysis system has demonstrated to be a useful tool for future CCHP designs with SOFC/GT systems.Copyright