Fuel Cells – Innovative Systems for Power Generation Fuel Cells For Power Generation

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause211/ General aspects 2.Design and function of fuel cells 3.Hydrogen generation for fuel cells 4.Fuel cell applications Content

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause311/2005 Principle of a fuel cell compared to conventional power generation conventional power generation Chemical energy of fuel Thermal Energy Mechanical Energy Electricalenergy fuel cell Steam power station / combustion engines Direct electrochemical conversion

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause411/2005 Advantages High efficiency in small and large power units High efficiency in small and large power units High efficiency over the whole control range High efficiency over the whole control range Therefore fuel cells are suitable for distributed power supply distributed power supply in domestic applications in domestic applications

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause511/2005 Comparison of theoretical electrical efficiency between fuel cell process and combustion processes Combustion process Carnot cycle Fuel cell process

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause611/2005 Electrical efficiency of different power generation systems

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause711/2005 Electrical efficiency in the part load range

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause811/2005 General parts of a fuel cell system Fuel processing unitFuel cell unit primary fuel: natural gas desulphurization reformer water air CO - converting heat hydrogen rich gas off gas alternating current digital current inverter fuel cell

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause911/ General aspects 2.Construction and function of fuel cells 3.Hydrogen generation for fuel cells 4.Fuel cell applications Content

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause1011/2005 Maximum obtainable work of a chemical reaction H 2 + ½O 2  H 2 O  H r =  G r + T  S r  G = - n F E 0  H = - n F E 0 H Ideal efficiency of a reaction Real conditions Fuel cell discharge mode:  G + n F E < 0 Electrolysis mode:  G + n F E > 0 Fundamentals:

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause1111/2005 Dependence of cell voltage E on the currant load

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause1211/2005 Thermodynamic data for fuel cell reactions under standard conditions (1,013 bar, 298 K) FuelReactionn -  H 0 [kJ/mol] -  G 0 [kJ/mol] E 00 [V]  th [%] Hydrogen H 2 + ½O 2  H 2 O l 2286,0237,31,22983,0 CO CO + ½O 2  CO ,1257, ,9 Formic acid HCOOH + ½O 2  CO 2 + H 2 O l 2270,3285,51,480105,6 Methanol CH 3 OH + 1½O 2  CO 2 + 2H 2 O l 6726,6702, ,7 Methane CH 4 + 2O 2  CO 2 + H 2 O l 8890,8818, ,9

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause1311/2005 Thermodynamic cell voltage and ideal efficiency under different temperatures FuelReaction 298 K E 00 [V]  th [%] 600 K E 00 [V]  th [%] 1000 K E 00 [V]  th [%] Hydrogen H 2 + ½O 2  H 2 O g 1,18941,11881,0078 CO CO + ½O 2  CO 2 1,34911,18811,0169

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause1411/2005 General characteristics of fuel cells

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause1511/2005 Principleof fuel cells fuelair anode off gascathode off gas anodecathode electrolyte gas permeable catalyst collector with gas feeder

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause1611/2005 Types of fuel cells

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause1711/2005 Electrical characteristic of Hydrogen PEM-FC maximum voltage 1,23 V at 25°C, 1 bar minimum voltage 0,33 V (possible electrolysis) typical current density 0,75 A/cm² Dependence of cell performance on media pressure

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause1811/2005 Electrical characteristic of Hydrogen PEM-FC-Stack

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause1911/2005 Requests to the fuel

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause2011/2005 Construction types of fuel cells

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause2111/2005 stack with end plates and contacts cell Assembly of a PEM fuel cell stack

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause2211/2005 PEM Fuel Cell Stack, Performance: 4 kW el.

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause2311/2005 PEM fuel cell stack from insight

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause2411/ General aspects 2.Construction an function of fuel cells 3.Hydrogen generation for fuel cells 4.Fuel cell applications Content

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause2511/2005 There is no existing up to now a sustainable hydrogen supply systemThere is no existing up to now a sustainable hydrogen supply system There is an existing natural gas infrastructureThere is an existing natural gas infrastructure Natural gas can be converted into hydrogen by reforming technologiesNatural gas can be converted into hydrogen by reforming technologies Why hydrogen generation by reforming of natural gas

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause2611/2005 Natural gas Desulphurization Reforming Water Air CO - cleaning Heat Hydrogen gas

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause2711/2005 Types of reforming processes of natural gas

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause2811/2005 evaporator reformer CO - conversion and fine cleaning HTTTSelOx burner water air desulphur. nat. gas compressormoistening off gas return heat buffer or heating system inverter conditioning fuel cell stack 

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause2911/2005 Low temperature desulphurization with activated carbon:  is necessary for sulfur sensitive catalysts (most)  adsorbs also higher hydrocarbons ( odor substances) High temperature desulphurization with oxidic absorbents (ZnO):  using non sulfur sensitive catalysts for prereforming  convert all sulfur compounds into H 2 S.  forming ZnS (higher capacity of desulphurization) Desulphurization sulfur content, input : natural gas < 5 mg/m³ reforming gas < 3,5 ppm

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause3011/2005 Advantages of Steam Reforming  High hydrogen concentration  high utilization of the reforming gas  By separate supply of energy and raw gas  the energetic use of the off gas from the fuel cells, in the reforming process is possible.  Steam reforming offers the possibility to using the calorific value.  High technical complexity for the facilities because of the heat transfer. Disadvantages

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause3111/2005 Steam Reformer Objectives: - Catalytic splitting methane to hydrogen - With smallest expenditure of energy - With low carbon monoxide content in the product gas Main reactions: CH 4 + H 2 O  CO + 3H 2  H R = 206 kJ/mol CH 4 + 2H 2 O  CO 2 + 4H 2  H R = 165 kJ/mol Energy supply: - Over an external surface burner - Recycling of the residual reforming-gas from the fuel cell - Heat recovery from the reformat gas to the raw gas

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause3211/2005 Equilibrium Concentrations of Steam Reforming Process temperature, [°C] CH 4, CO, CO 2 - concentration H 2 - concentration

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause3311/2005 Power Consumption for Hydrogen Generation by Steam Reforming Without heat recovery temperature, [°C] Power requirement related to H 2 [kJ/m 3 ]

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause3411/2005 CO - Shift - Conversion Objectives: - Catalytic transformation of carbonmonoxid With free water from the reforming process - After the reaction: carbonmonoxid concentration < 1 % Main reaction: CO + H 2 O  CO 2 + H 2  H R = - 41 kJ/mol Use of energy: - provide for heating

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause3511/2005 Equilibrium Concentration of CO-Shift-Conversion Specifications for dry Reformat Reformat = 700°C p = 1,8 bar S/C = 3,0 H 2 - concentration CO, CO 2 - concentration temperature, [°C]

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause3611/2005 Preferential Oxidation Objectives: - catalytic transformation of carbonmonoxid with oxygen (air) - after the reaction: carbonmonoxid concentration < 10 ppm Main Reactions: CO + ½ O 2  CO 2  H R = kJ/mol H 2 + ½ O 2  H 2 O  H R = kJ/mol Energy recovery: - disposition for heating

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause3711/2005 Change of the Gas Composition durning the Steam Reforming Process and Gas Purification Preferential OxidationCO-Shift-ConverterSteam-Reformer O

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause3811/2005 Different forms of catalysts

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause3911/ General aspects 2.Construction an function of fuel cells 3.Hydrogen generation for fuel cells 4.Fuel cell applications Content

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause4011/2005 Motor vehicles with PEMFC DaimlerChrysler GM Opel Ford Fiat Toyota Volkswagen DaimlerChrysler Ballard MAN Siemens

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause4111/2005 H Power Corporation Fraunhofer Institut für Solare Energiesysteme Independent power supply of portable appliances

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause4211/2005 HowaldswerkeDeutscheWerft Poewer supply of space craft and submarines with fuel cells International Space Station ISS Space Shuttle

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause4311/2005 Heat and Electricity Consumption Heat and Electricity Consumption in a Standard Domestic Application in Germany

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause4411/2005 PlugPower Sulzer Hexis HGC (Energiepartners) Fuel Cell Systems for Domestic Applications Vaillant

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause4511/2005 Vaillant BZH Electric Power: 1 - 4,6 kW Thermal Power: 1,5 - 7 kW Electrical Efficiency: 30 % Overall Efficiency:> 80 % Working Temperature:70 / 55 °C

Fuel Cells – Innovative Systems for Power Generation Dr.-Ing. Hartmut Krause4611/2005 Sulzer Hexis HXS 1000 Premiere Elektrische Leistung:max. 650 W Thermische Leistung, ges.:15/19/25 kW (mit integriertem Brennwertgerät) Brennstoffzelle: elektr. Wirkungsgrad:20 % Gesamtwirkungsgrad:85 %