Andrzej Miller

Influences of The Type and Thickness of Electrolyte on Solid Oxide Fuel Cell Hybrid System Performance

This paper sets out the results of mathematical modeling and numerical simulations with regard to the influences of the type and thickness of electrolyte on Solid Oxide Fuel Cell Hybrid System (SOFC-HS) performance. A change of electrolyte materials can result in total hybrid system efficiency increasing from around 48% HHV (53% LHV) to about 65% HHV (72% LHV) in an environment where turbine inlet temperature and gas turbine subsystem pressure ratio remain unchanged. The governing equations of SOFC-HS modeling are given. An adequate simulator of the SOFC stack was made and described. Based on this simulator, a model of the 260 kWe Siemens Westinghouse unit was built. The performance of this SOFC-HS with different electrolyte materials and thicknesses is shown, and some characteristics are given and described. The advantages and disadvantages of different electrolyte types from a hybrid system performance point of view are indicated.

Reducing CO2 Emissions From a Coal Fired Power Plant by Using a Molten Carbonate Fuel Cell

A Molten Carbonate Fuel Cell (MCFC) is shown to reduce CO2 emissions from a Coal Fired Power Plant (CFPP). The MCFC is placed in the flue gas stream of the coal fired boiler. The main advantages of this solution are: higher total electric power generated by a hybrid system, reduced CO2 emissions and higher system efficiency. The model of the MCFC is given and described. The results obtained show that use of an MCFC could reduce CO2 emissions by 56%, which gives a relative CO2 emission rate of 288 kgCO2 per MWh.Copyright

Mathematical Model of SOFC (Solid Oxide Fuel Cell) for Power Plant Simulations

Presentation of concept of SOFC model is given. The SOFC model was built in HYSYS.Plant environment based on its standard libraries. Main elements of SOFC model and chemical reactions are presented. Selected performance characteristics at the design point of stand-alone SOFC are presented. The new equation to define of SOFC voltage, which was obtained based on new assumptions and which can be used instead of the Nernst equation, is given.© 2004 ASME

The Reduction of CO2 Emission of Gas Turbine Power Plant by Using a Molten Carbonate Fuel Cell

The possibility of using a Molten Carbonate Fuel Cell (MCFC) to reduce the CO2 emission from Gas Turbine Power Plant (GTPP) is shown. The MCFC is placed after a gas turbine. The main advantages of this solution are: higher total electric power generated by hybrid system and reduced CO2 emission with remained system efficiency. A comparison of three systems: standard GTPP, GT-MCFC, and GT-MCFC with additional heat exchangers is shown. The application of MCFC could reduce CO2 emission of 73% (absolutely) and 77% relative to produced power.Copyright

Gas Turbines in Unconventional Applications

The next section describes hydrogen-fuelled gas turbine solution. Big international programme – WE-NET – is discussed. Several hydrogen-fuelled gas turbine concepts based on those programmes are proposed: Westinghouse, Toshiba, Graz, New Rankine. The section provides description of them all, including specification of possible efficiency values. The development programmes themselves are also reviewed. This part of the text describes also potential combination of a hydrogen-fuelled gas turbine and a nuclear power generation unit which might be used to cover peak load power demands in a power system.

The control strategy for a Solid Oxide Fuel Cell Hybrid System

Based on mathematical modeling and numerical simulations, the control strategy for a Solid Oxide Fuel Cell Hybrid System (SOFC-HS) is presented. Adequate maps of performances with three independent parameters are shown. The independent parameters are as follows: stack current, fuel mass flow and turbine-compressor shaft speed. Those parameters can be controlled by external load, fuel valve and turbine-compressor shaft speed, respectively. The control system is purposed to meet many constraints: e.g. stack temperature, steam-to-carbon ratio, compressor surge limitation etc. The aim is to achieve maximum efficiency of power generated within those constraints. Governing equations of SOFC-HS modeling are given. An adequate simulator for the SOFC module was produced and described. Based on this simulator, the control strategy was obtained. The performance of this SOFC-HS is shown in various working environments.

The Control Strategy for a Solid Oxide Fuel Cell Hybrid System

Based on mathematical modeling and numerical simulations, the control strategy for a Solid Oxide Fuel Cell Hybrid System (SOFC-HS) is presented. Adequate maps of performances with three independent parameters are shown. The independent parameters are as follows: stack current, fuel mass flow and turbine-compressor shaft speed. Those parameters can be controlled by external load, fuel valve and turbine-compressor shaft speed, respectively. The control system is purposed to meet many constraints: e.g. stack temperature, steam-to-carbon ratio, compressor surge limitation etc. The aim is to achieve maximum efficiency of power generated within those constraints. Governing equations of SOFC-HS modeling are given. An adequate simulator for the SOFC module was produced and described. Based on this simulator, the control strategy was obtained. The performance of this SOFC-HS is shown in various working environments.

The Application of µ-Fan Instead of the Ejector in Tubular SOFC Module

The possibility of using a μ-fan in tubular SOFC module is shown. The μ-fan is placed instead of the ejector and has the same role. Main advantages of this new solution are: lower power demanded by fuel compressor (blower), more stable working characteristic, and possibility of control of re-cycled part of anode gas during part load operation. Comparison of two SOFC Modules: with and without the ejector is also shown and commented.Copyright