Principles and applications of high temperature ion conducting ceramic in power generation - fuel cells and oxygen membranes

High temperature membranes can be used in numerous applications including ceramic filters, selective sieves, removal of impurities, oxygen and hydrogen separation, electrochemical devices such as solid oxide fuel cells and solid oxide electrolysers. The fabrication process is oriented at achieving desired properties of the final product, including proper conductivity, size and density of pores, tortuosity, mechanical stability in high operating temperatures and others. Among the mentioned applications, solid oxide fuel cells and oxygen separation membranes represent materials with mixed ionic and electronic conductivity (MIEC) which will be further discussed in the lecture. Such material are often referred as membranes designed specifically for transport of ions and electrons

Progress of the IAHE Nuclear Hydrogen Division on international hydrogen production programs

This paper presents recent activities of the IAHE Nuclear Hydrogen Division and associated research advances in Canada, China, France, Germany, Poland, and Romania on programs and major initiatives on large-scale hydrogen production and utilization. Germany and France have made significant advances in high temperature steam electrolysis (HTSE). Germany is going to demonstrate a 3-kW steam electrolyzer and 100-kW Hybrid Sulfur Cycle powered by solar energy soon. France operated several HTSE 25-cell stacks at various operating points. Recently, a HTSE packaged system has been built, containing this 25-cell stack and other Balance of Plant components. At 700 °C, this system produces 1.2 Nm3/h of H2 with a total electrical consumption of 3.9 kWh/Nm3, achieving 92% of efficiency (electrical consumption of the system vs HHV of the produced hydrogen). It demonstrates that a 150 °C heat source temperature is sufficient for the steam generation, and that a slightly exothermic operating mode of the stack is sufficient to preheat the inlet gas up to 700 °C and compensate the heat losses of the system. China has also made significant progress in developing the HTSE process at a hydrogen production rate of 105 dm3/h and the thermochemical Sulfur–Iodine (SI) cycle at the rate of 60 dm3/h, which already achieved the goal of China's HTR-PM Demonstration Nuclear Power Plant Project. The components and facilities were developed and tested in Tsinghua University. Romania is collaborating with Canada on nuclear hydrogen production with the thermochemical Cu–Cl cycle. The individual unit operations of the Cu–Cl cycle have been verified experimentally. Research on integration of a laboratory scale system to produce 3 kg of hydrogen per day is underway at the University of Ontario Institute of Technology in Oshawa, Ontario. Poland has developed advanced simulation capabilities for Solid Oxide Fuel/Electrolysis Cells for hydrogen peak energy storage as well as laboratory scale experiments focused on solid oxide and molten carbonate fuel cells. This paper presents a review of activities of members of the IAHE Nuclear Hydrogen Division in these six countries

Modelling of Physical, Chemical, and Material Properties of Solid Oxide Fuel Cells

This paper provides a review of modelling techniques applicable for system-level studies to account for physical, chemical, and material properties of solid oxide fuel cells. Functionality of 0D to 3D models is discussed and selected examples are given. Author provides information on typical length scales in evaluation of power systems with solid oxide fuel cells. In each section, proper examples of previous studies done in the field of 0D–3D modelling are recalled and discussed

Considerations regarding modeling of MW-scale IG-SOFC Hybrid Power System

RES Master´s Thesis Verkefnið er unnið í tengslum við Háskóla Íslands og Háskólann á AkureyriThe main objective of this thesis is to evaluate various modeling approaches for large systems employing high temperature fuel cell (particularly SOFC) modeling. It also includes a brief discussion of current trends and various designs. This thesis will review recently published papers investigating the hundred MWe scale SOFC hybrid Brayton-Rankine power systems. It goes into details discussing the crucial parameters influencing the cycle’s operation and performance. For better understanding, the basics of the fuel cell operation, involved processes and all phenonena are provided in Chapter 2. In the next chapter the SOFC based systems with integrated gasification reactors are widely described. Current state-of-the-art trends and their background are presented. Finaly the desired system configuration is proposed and investigated. These particular arragements correspond to the U.S. Department of Energy (DoE) baseline for systems employing high temperature fuel cells, hence certain design solutions are involved. The SOFC stack feedstock is provided by the gasification of coal, however different fuel can also be gasified (biomass for example). In the last chapter, the modeling and optimisation in the software are extensively described. Because of the fact that ASPEN Plus and Hysys are comonly used in the majority of cases when cycles involing high temperature fuel cells are analyzed, the attention will be focused on these two programs. Both of them have built-in tools allowing the modeling of heat exchangers, compressors and expanders (i.e. gas and steam turbines) by available units. ASPEN Plus is Fortran based software and the SOFC stack can be modeled as a user unit using this programming code. The modeling approach to the electrochemical and chemical processes within the SOFC stack will be delivered, since it is important for the modeling of the entire power cycle. Analysis of the whole system with the proposed tools allows the determination of the overall system thermal efficiency with high fidelity, thus the biggest effort must be made to correctly determine all input parameters and define the proper assumptions as well as simplifications. The final discussion emphasises the most crucial parameters. The proposed system represents a clean energy source, which substantialy reduces the polutants flow associated with the power generation. Desulphurisation and gases clean-up processes are also involved in the cycle, therefore it meets all environmental requirements

SOFC-based micro-CHP system as an example of efficient power generation unit

Microscale combined heat and power (CHP) unit based on solid oxide fuel cells (SOFC) for distributed generation was analyzed. Operation principle is provided, and the technology development in recent years is brie.y discussed. System baseline for numerical analysis under steady-state operation is given. Grid-connected unit, fuelled by biogas corresponds to potential market demand in Europe, therefore has been selected for analysis. Fuel processing method for particular application is described. Results of modeling performed in ASPEN Plus engineering software with certain assumptions are presented and discussed. Due to high system electrical efficiency exceeding 40%, and overall efficiency over 80%, technology is an example of highly competitive and sustainable energy generation unit