SOFC Power Generation Research Articles

Improvement of SOFC System Efficiency by Incorporating Thermoelectric Power Generation Heat Exchanger

The effects of replacing a water heater at a bottom of 700 W class SOFC system with thermoelectric generation heat exchanger (TEG-HEX) was investigated by numerical simulation. A 2205 cm3 large TEG-HEX can generate additional power of 11.5 W in the case of each TE element height = 0.9 cm and heat transfer enhance rate = 3.0. This output power corresponds to improvement of SOFC power generation efficiency by 0.756 points. Increasing TE elements height are effective to increase output power of TEG-HEX, however, this leads to substantial decrease of power density estimated on TE elements volume. Decrease in the power density leads directly to higher cost, thus we should regard the power density as guiding principle of practical design. In addition, 30 % of the downstream of the TEG-HEX generate low power, thus cutting down this wasted part leads to improved power density and cost.

Research on Fuel Cell Power Generation System Model with Grid

The paper take the solid oxide fuel cell (Solid Oxide Fuel Cell, SOFC) as the object, studies the influence of the fuel cell on load characteristics of the distribution network. Structures based on Matlab simulation platform contains the SOFC typical distribution network, and a series of transient simulation was conducted, results indicate that the SOFC power generation system can be describe in its equivalent model based on the URL equivalent circuit-order differential equation of state. On this basis, the access to the distribution network SOFC power generation system regarded as power consumption of the negative dynamic load, proposed containing the SOFC can be to the equivalent the GSLM model containing the SOFC described distribution grid load characteristics.

A self-sustaining thermal transpiration gas pump and SOFC power generation system

A self-sustaining thermal transpiration-based combustor and gas pump system having no moving parts and using readily storable hydrocarbon fuel is presented. Thermal transpiration was accomplished by meeting two essential conditions: (1) gas flow in the transitional or molecular regime using glass microfiber filters as transpiration membranes and (2) a temperature gradient through the membrane using catalytic combustion downstream of the membrane. Experiments showed that transpiration pumps with larger porosity and larger overall size exhibited better performance, though membrane pore size had little effect. These results were quantitatively consistent with theoretical predictions. By exploiting the temperature and fuel/oxygen concentrations within the transpiration pump, a novel, complete portable power generation system was created using a single-chamber solid-oxide fuel cell and its performance is reported.

SOFC Power Generation from Biogas: Improved System Efficiency with Combined Dry and Steam Reforming

Solid oxide fuel cell systems (SOFC) can improve the efficiency of electrical power generation from biogas compared to small scale CHP units. The SOFC requires a reforming step converting biogas into synthesis gas (hydrogen and carbon monoxide). . Dry reforming of methane with the carbon dioxide contained in biogas is a promising approach to produce high caloric SOFC fuel gas, but carbon formation is predicted for all typical biogas compositions. To avoid carbon formation and to compensate fluctuating biogas compositions additional supply of steam is essential leading to a combined dry and steam reforming. The paper describes the system approach, upfront analysis, biogas monitoring results, process unit design and evaluation as well as the system setup to demonstrate a biogas to electricity route with a gross efficiency of 45 % using a commercial 1 kW SOFC stack.

Progress on SOFC Power Generation Module and System Developed by NTT, SPP and THG

An SOFC system generating a 5 kW-class AC output power has been developed to demonstrate high electrical efficiency over 1000 hours. The SOFC mono-generation system, consisted of a power generation module and a balance of plant. We have measured the characteristics of the SOFC system, namely, the electrical efficiency at the rated output power, the power consumption of the BOP, and the DC/AC conversion efficiency of an inverter. This paper describes the system configuration and design points that make it possible to achieve high performance. In addition, the experimental results reveal the long-term voltage stability and the electrical efficiency of the SOFC system.

IP-SOFC Performance Measurement and Prediction

Rolls-Royce Fuel Cell Systems (RRFCS) is currently developing a stationary 1MW SOFC power generation system based on Integrated-Planar SOFC technology. RRFCS is also developing state of the art numerical prediction tools that will be used to support fuel cell product design. One such tool, the Multi-Physics Code (MPC), is based in the STAR-CCM+ (CD-adapco) computational fluid dynamics software package. This paper is concerned with the validation of MPC predictions against fuel cell current-voltage (IV curve) measurements made from singe-cell tests. Validation results are presented for 31 sets of IV curves which illustrate the effect of changing gas conditions and material properties on cell performance. The calculated mean computational errors are 0.3% for open circuit potential predictions and 1.7% and 4.4% respectively for predictions of cell potential at maximum current density and cell area specific resistance.

SOFC Power Generation from Biogas - Maximize the System Efficiency with Combined Dry-/Steam Reforming

not Available.

Progress on SOFC Power Generation Module and System Developed by NTT, SPP and THG

not Available.

Development of 1 kW SOFC power package for dual-fuel operation

A compact SOFC power generation system was developed by integrating a 1 kW SOFC stack and balance-of-plant. The system was designed for dual-fuel operation using both natural gas (NG) and liquefied petroleum gas (LPG). An adiabatic pre-reformer was employed in a fuel processing system to convert C 2+ hydrocarbons in the fuel into CH 4-rich gas which was further processed in a main reformer to produce H 2-rich gas for the SOFC stack. The SOFC system was operated for 350 h under thermally self-sustaining condition, and on-load fuel switching from NG to LPG was carried out during the operation. The system performance was not significantly affected by NG/LPG composition ratios and the performance was stable during continuous operation in NG or LPG.

고체산화물 연료전지 발전시스템의 최근 연구 개발 동향

본 논문에서는 고체산화물 연료전지의 스택 제조 및 시스템 연구개발의 최근 연구동향을 살펴보았다. 고체산화물 연료전지는 연료의 화학적 에너지를 전기적 에너지로 변환시킬 수 있는 친환경, 고효율의 전기화학장치이다. 고체산화물 연료전지 발전시스템은 응용분야에 따라 중대형 분산발전, 가정용 열병합 발전, 보조전원 및 휴대용 발전 시스템으로 구분할 수 있으며, 10 kW급 이상의 SOFC 발전시스템의 경우 원통형 셀로 구성된 발전시스템이 연구개발의 주를 이루고 있다. 더불어, SOFC 발전시스템 연구개발의 경우 매년 증가하는 세계 전력소비량에 대응하기 위해 발전시장에 진입 가능한 고성능, 장수명의 SOFC 소재 및 발전시스템에 R&D 노력이 집중되고 있다. This article reviews recent R&D trends in SOFC development with an emphasis on industries that can produce the SOFC stack and power generation system. SOFC is an electrochemical device that can convert the chemical energy of fuel into the electrical energy with environment friendly system and high efficiency. SOFC power generation system could be classified as the portable power generation system, auxiliary power unit(APU), residential power generation(RPG) and large size distributed power generation. In the case of more than 10kW system, the major R&D trends are focused on the tubular type SOFC system with high efficient and long term stability to meet the commercialization of SOFC power generation system.

Technical considerations of SOFCs for mixed DG/backup power applications

This paper discusses the technical considerations when SOFCs are used for mixed DG/backup power applications, where the SOFCs work as distributed generators that output power to the grid when the grid is connected, while pick up the critical load in an acceptable time scale and continue the power supply to this critical load during a grid blackout. The principle of SOFC power generation is described, with reference to a prototype of a real 110 kWe tubular SOFC combined heat and power system, which is manufactured by Siemens Westinghouse and has operated at TurboCare S.p.A (Siemens Group) Turin, Italy. The technical requirements for a mixed DG/backup power system are presented and the system structure is detailed with special consideration of the technical aspects of the power conditioning systems. Simulation results based on a Matlab/Simulink model are reported assuming a grid blackout and a step increase of the critical load.

Development of SOFC-Micro Gas Turbine Combined Cycle System

SOFC is able to attain extremely high efficiency over 70% as LHV, as gas turbine combined cycle system. Mitsubishi Heavy Industries (MHI) has been developing SOFC since 1984. Based on developed technologies, now MHI is on the step of integrating SOFC power generation system. MHI has improved the components and the control technology for the combined cycle system, that is, improvement of cell stack, verification of pressurized operation and control of SOFC module and the combustor for low- calorie fuel. In 2006, MHI managed to operate the combined cycle system with maximum combined power output of 75kW, for the first time in Japan. And now, MHI is ready to manufacture a 200kW class SOFC-MGT combined cycle system, which will be operated in 2007.

Development of SOFC Residential Cogeneration System at Osaka Gas and Kyocera

At 2004, Osaka Gas Co., Ltd. and Kyocera Corporation launched joint development of SOFC residential cogeneration system, aiming for the commercialization. To demonstrate the technical achievement, we installed SOFC residential cogeneration system in a house and carried out operation. At rated power, ac 1kW, net ac efficiency and hot water heat recovery efficiency were 49% (LHV) and 34%(LHV), respectively. The mean net ac efficiency of each day, that is total efficiency of 24 hours, ranged 42-48 % (LHV), when the mean net ac power of SOFC were 480-680W. We demonstrated that this system is good for decreasing CO2 emission. At the end of 2006, we developed new SOFC power generation unit. It was reduced its size nearly half in the volume, in order to fit Japanese house in the city.

Solid Oxide Fuel Cell Development at Forschungszentrum Juelich

AbstractSolid oxide fuel cell (SOFC) development work at Forschungszentrum Juelich (FZJ) is extensive, ranging from fundamental materials' design through to near‐commercial prototype CHP systems. Considerable advances have been demonstrated in the past years concerning the improvement of device performance by identifying performance degradation mechanisms and reducing or eliminating those problems, and in designing, developing and manufacturing core SOFC components. At the time of this writing, the first, fully integrated SOFC combined heat and power generation prototype system is awaiting completion. FZJ is involved in significant national and international programs and coordinates major international projects.

Application of power electronics with the US DOE distributed generation programme

Power electronics play an important role in achieving affordable, highly fuel-efficient fuel cell power generation plants and will enable the US Department of Energy's Office of Fossil Energy Fuel Cells programme to achieve higher national goals: environmental, economic and energy security. The initial focus on power electronics has been to understand the interactions between the SOFC stack, the power conditioning subsystem and the application load requirements and dynamic behaviour. Advances in lower-cost and high-efficiency power electronic converters and inverters are a major factor in achieving attractive simple cycle fuel to electricity conversion efficiencies of 50% to 60% for DG fuel cell power plants. Functionality and performance requirements for power conditioning subsystems will vary between the numerous possible applications for SOFC power generation technology, providing a highly interesting and challenging future in power systems product engineering and development.

OS5-5 円筒形SOFC高効率コンバインドサイクルシステムの開発(OS5 水素・燃料電池,分散と集中の共存)

SOFC Power Generation System is able to attain extremely high efficiency over 70%, as Gas Turbine Combined Cycle System. Mitsubishi Heavy Industries (MHI) has been developing SOFC, since 1984 for material and production technology of Tubular Type Cell Stack, SOFC module, and system integration. In 2004, MHI has been commissioned to a new national project "Development of SOFC-Gas Turbine Combined Cycle System with Tubular Type Cell" by New Energy and Industrial Technology Development Organization (NEDO). The aim of this project is development and demonstration operation of 200kW class SOFC-Gas Turbine Combined Cycle System, with Tubular Type SOFC and Micro Gas Turbine. The target of performance is 200kW class electricity power output and 50%-LHV of power generation efficiency. This 200kW class SOFC-Micro Gas Turbine Combined Cycle System will be manufactured and operated in 2007.

OS5-01 低温型と高温型を直列配置した平板型SOFC発電のサイクル解析(OS5 水素・燃料電池)

In this study, two-stage SOFC cycle by series connection of low- and high-temperature SOFCs (Lanthanum gallate and YSZ electrolyte, respectively) and a gas turbine has been studied. This cycle can extend the operating temperature range of SOFC and may increase a total power generation efficiency. This report has estimated system efficiency by cycle analysis of two-stage SOFC power generation with gas turbine. Fuel and air recirculation and external reforming have been adopted in this calculation. Physical properties and activation overpotential of low-temperature SOFC were based on recent published data and they are relatively superior to those of high-temperature SOFC. The analysis result shows the SOFC power generation efficiency of 50.3% and total power generation efficiency of 56.1% under a standard condition (low-temperature FC average temperature: 1023K, current density: 0.3A/cm^3, cell pressure: 1.0MPa, total fuel utilization ratio at PCs: 85%). The total power generating efficiency increases with increases of low-temperature SOFC average temperature and fuel and air utilization ratios, respectively. It also shows a positive cell pressure dependence, but peaks out around 1.0MPa.