Development of PEMFC-APU systems for truck application Per Ekdunge 15 May 2012 World Renewable Energy Forum, WREF 2012, Denver, USA
Powercell Sweden Located in Gothenburg Sweden 15 year heritage of technology, know-how and IP s from operations within Volvo Group. Operated as independent company since 2009 Solid financial stability for continued R&D work independent of revenue levels. Small revenue starting in 2011. Company build up on schedule including initial investments in facilities and infrastructure. Total area of 2500 m² which includes production, laboratory, and offices Per Ekdunge WREF 2012 2
Fuel Cells Benifits Direct Chemical Energy Conversion High Efficiency Low / Zero Emissions Wide Range of Applications / Distributed Installation Cogeneration Reliable Quiet Fuel Flexible Function Fuel cells combine hydrogen and oxygen Electrochemically to produce electricity. The only byproducts are water and useful heat. Per Ekdunge WREF 2012 3
For transportation Fuel Cells have the highest potential to contribute to energy security, climate protection and emission reduction Why fuel cell Fuel cells offer significantly higher efficiency in transport as well stationary applications Fuel cells are a zero emission technology when operated with hydrogen Fuel cell vehicles has good dynamics. Fuel cell vehicles provide options for further electrification of the vehicle (e.g. air conditioning while standing) Fuel cell vehicles has low noise emission Which fuel? Low temperature fuel cell use hydrogen as fuel, but; There exist no hydrogen fuel infrastructure. Huge investments are need for a new fuel infrastructure. Technical breakthrough is needed in hydrogen storage, distribution and production. Per Ekdunge WREF 2012 4
Why a diesel fueled APU based on reforming and LT-PEM? Pollutions US Market 2.3 million large diesel trucks in the US. 600,000 have sleeper cabs (1). A typical intercity tractor-trailer idles an estimated 1800 h/year (2) Fuel cell APU can reduce CO 2 emission with 8.9M ton/year (3) Demand Last one owner, 5 years >9000h, ~2000 start and stop TCO competitive Freeze capable Using existing fuel infrastructure Legislation Eliminate idle operation of the diesel main engine Lower emissions of NOx and hydrocarbons Cost efficiency Decrease the fuel cost by higher efficiency Compact and reliable Power Systems Enhanced comfort Reduced noise and vibration Reduce noise pollution in cities (1) Source: US Census Bureau, 2002 Economic Census (2) Argonne National Laboratory, US Department of Energy (3) DOE Hydrogen Program Record,2009 Per Ekdunge WREF 2012 5
Technology choice for the APU based on demand ATR technology was chosen due to need to be self sustained by heat and trade-off for efficiency. The LT-PEM technology was chosen after real life testing of the daily APU truck demands regarding the high numbers of start and stop of the APU system. The reformer sub-system needs to fulfill the high demand of LT-PEM requirements of virtually zero NMHC, and below 20 ppm CO level. Some of the advantages for using Fuel cell APU compared to commercially available diesel engine APU s are: Fuel Efficiency: 50-100% better than todays solutions Emissions: Zero regulated emissions Noise: Very low noise Durability: Significant improvement expected Per Ekdunge WREF 2012 6
Results from APU development system Lab-system 200h operation (1000h reformer) 100 start and stop (500 reformer) Thermal load (kw) 8 10 12,5 15 17 Reformer System Efficiency 80 83 84 84 86 H 2 (%), Dry gas 44 44,4 44,9 45,3 45,7 CO 2 (%), Dry gas 22,3 22,4 22,4 22,5 22,5 CO (ppm), Dry gas <20 <20 <20 <20 <20 CH 4 (ppm), Dry gas 80 80 100 100 100 H 2 O (%) Total flow 33 33 33 33 33 Conclusion Core components did not fail (reformer and fuel cell stack) Stable BoP is the focus for uninterruptable operation CO level is low and stable No NMHC slip Start up is important to master and requires by-pass mode of the stack Improvement of pressure drop is needed Per Ekdunge WREF 2012 7
Demand on reformer system Demand from System Self sustained by heat Large number of start and stop Freeze capable Short start up time Self sustained with water balance Conventional diesel (US10) Demand from Fuel Cell Low CO level Clean from NMHC High humidity High H 2 content Low temperature No Sulfur Demand on Reformer CO < 20ppm at steady-state, < 50 ppm during transients, PrOX reactors needed as well as Sulfur trap Compact and low weight (start-up and gross weight perspective) Low pressure drop Per Ekdunge WREF 2012 8
Results from reformer system C H n C H n Autothermal Reforming T: ~ 650 ºC Partial Oxidation (POX) m m n m 2O2 nco 2 H2 Steam Reforming nh O Energy m n 2 2 2 Energy nco H Water gas shift T: 250 350 ºC CO H2O CO2 H2 Energy Preferential Oxidation T: 100 210 ºC CO H 2 1 2 1 2 O O 2 2 CO Energy H O Energy 2 2 Desulferisation T: 300 ºC ZnO H 2S ZnS H2O Per Ekdunge WREF 2012 9
Conc. (ppm) Concentration (ppm) Results from reformer system To be able to follow load changes in the demand the CO level need to be stable so that the Fuel Cell do not suffer poisoning Below the CO level is below 50ppm during load changes Slip of NMHC from the reformer is important to avoid 250 200 150 100 50 0-50 250 200 150 100 50 0-50 Benzene Diesel 822.5 823 823.5 824 824.5 Time (min) 0 30 60 90 Time (s) Per Ekdunge WREF 2012 10
Demand on fuel cell stack Demand from user Low cost (to get competitive TCO and low spare part cost) Low weight Low volume Many start and stops Freeze capable Durability Demand from system Reformate compatibility (>45%H 2, <20ppm CO average) Low Pressure drop Good fuel utilization Stability (low stoich, hum) High operating temperature for cooling (T>75 C) The LT-PEM has been chosen as the technology due to it is the most mature and at the moment the choice for mass-production for the automotive industry Offers the most compact stacks due to formed thin sheet metal BPP Only technology that can tolerate the number of start and stop required Per Ekdunge WREF 2012 11
Design Challenges for a reformate APU fuel cells Lowering of pressure drop A low pressure drop creates a need for large aspect ratio to achieve high enough gas velocities through stack to efficiently remove liquid water (rectangular shape) Fuel utilization / pressure drop trade off Trade off between fuel utilization at partial load and pressure drop at nominal load Robustness towards manufacturing errors The depth of the channels must yield tolerance towards different GDL intrusions when under compression while still being shallow enough to facilitate high gas velocities Robust operation The flow field design should be insensitive towards liquid water in specified operating window Per Ekdunge WREF 2012 12
Stack voltage / V Total stack power / kw Pressure drop / mbar Results fuel cell performance H2 15% N2 Reformate H2 15% N2 Reformate Anode - H2 15% N2 Anode - Reformate Cathode 30 4 180 25 3,5 3 160 140 20 15 2,5 2 120 100 80 10 1,5 60 5 1 0,5 40 20 0 0 0 50 100 150 200 250 Current / A 0 0 50 100 150 200 250 Current / A Pin 200mbar, T = 85C, RH 80% stoichiometry A/C 1.25/2.0 (left) Polarisation behavior of the stack with H 2 and diesel reformate (right) Pressure drop Conclusion: 5-10% lower voltage with diesel reformate than hydrogen Pressure drop is and <100 mbar in desired operating window Per Ekdunge WREF 2012 13
Results fuel cell stability (left) anode stochiometry, diesel reformate 85 C, RH 80%, voltage normalized vs. voltage at low current stoichiometry 1.8 (right) Normalized cell voltage (RH 110%) dependency of cathode dew point. Per Ekdunge WREF 2012 14
European Project on Fuel Cell APU development Project name: Fuel Cell Based On-board Power Generation Project acronym: (FCGEN) Programme: Seventh Framework programme of the European union Grant agreement no. : (277844) Start date: 2011-11-01 End date: 2014-10-31 Project budget : 10 338 414 Planned on-vehicle demonstration of FCGEN APU on an IVECO truck. Project supported under Grant Agreement FCH-JU 277844 Per Ekdunge WREF 2012 15
Project partners Beneficiary name Country Responsibility 1. Volvo Technology AB Sweden - Coordination - FC stack and FP system testing 2. Powercell Sweden AB Sweden System integration and BoP optimization 3. Forschungszentrum Juelich GMBH Germany Fuel reformer and catalytic burner development 4. Institut Jozef Stefan Slovenia Development of the APU control system 5. Centro Ricerche Fiat SCPA Italy APU assembly on a truck and demonstration 6. Institut fuer Mikrotechnik Mainz GMBH Germany Development of CO clean up components 7. Johnson Matthey PLC. UK Catalyst development (FP) 8. Modelon AB Sweden System design and modeling Project supported under Grant Agreement FCH-JU 277844 Per Ekdunge WREF 2012 16
Project Objectives To develop and demonstrate a proof-of-concept complete fuel cell based 3 kw (net el.) auxiliary power unit in a real application, on-board a truck. The project will further develop the key components and subsystem technologies that have been advanced by the project partners in previous collaborations and move them closer towards commercially viable solutions. Issues 3-5 kw Diesel APU Durability (hours) 20000* Cost (Euro/kW) 1000 Efficiency 30% Weight (kg) Volume (L) 125 300 The targets for FCGEN also include significant reductions in fuel consumption: 80% reduction compared to conventional idling (>4 litres/hour) 40% reduction compared to diesel based APU * This is the design guideline which the project partner will use for the development of the materials, components and the system Project supported under Grant Agreement FCH-JU 277844 Per Ekdunge WREF 2012 17
Balance of Plant Components (BoP) FP: to produce high quality H2 rich reformate from the on-board fuel. system parts: (i) fuel reformer to convert diesel to syngas (ii) sulfur trap for sulfur removal from the reformate (iii) Microchannel heat exchanger coated with catalytic material for CO clean up (iv) Catalytic burner to oxidize anode off gas hydrogen and generate steam Fuel Processor (FP) Fuel Cell Stack (FCS) Control System (CS) Power Conditioning BoP: includes components for (i) air, water, fuel supply (ii) T and P sensors and actuators (iii) heating, cooling, humidification and water separations Project supported under Grant Agreement FCH-JU 277844 Per Ekdunge WREF 2012 18
Balance of Plant Components (BoP) FCS: To produce electricity from hydrogen oxidation in air. PEM-FC stack from PowerCell is used in the FCGEN project. Stack development is not included in this project Fuel Processor (FP) Fuel Cell Stack (FCS) Control System (CS) CS: on-line control of the APU and its subsystems, taking into account all technical constraints for the individual units Power Conditioning Power conditioning: to convert the variable DC voltage produced by a FCS into usable DC power as appropriate to meet the operating requirements of the intended application. Project supported under Grant Agreement FCH-JU 277844 Per Ekdunge WREF 2012 19
Necessary component developments addressed by the FCGEN project Fuel cell APU system components Stack components Challenge addressed Durability, tolerance to impurities Fuel processing Gas purification Balance of Plants Control system and power electronics Catalyst Materials Components Catalyst Materials Components Air compressor Blower Humidification Heat exchanger DC/DC converter ECU Weight and volume reduction, Cost, manufacturing, Start-up time Weight and volume reduction, Cost, manufacturing, Start-up time Efficiency, performance, cost, size and weight, optimum system packaging, noise level Efficiency, performance, cost, size and weight Project supported under Grant Agreement FCH-JU 277844 Per Ekdunge WREF 2012 20
Progress so far System design freeze. On-going work between project partners and external component suppliers for BoP component optimization. On-going work for detailed project plan, risk management, dissemination and exploitation plans. Catalyst material development at JM. On-going work to evaluate the compatibility of some of the materials in the system with hydrogen. Vehicle interface and specifications are defined. Project supported under Grant Agreement FCH-JU 277844 Per Ekdunge WREF 2012 21
Summary Fuel cell APU has a big potential to reduce fuel consumption and emission from heavy duty trucks PowerCell Sweden AB is a company doing fuel cell stacks, diesel reformer and complete electric generators. Due to the demand from the market the choice of technology is ATR for reformer and LT-PEM for the fuel cell stack The reformer can provide a gas quality good enough for the fuel cell stack The fuel cell stack can handle the demand from the system Further development is needed before the complete product is ready and commercial, meanwhile PowerCell offers the S1 fuel cell stack product to the market. The European project FCGEN will advance the fuel cell APU technology, based on a strong multinational cooperation Per Ekdunge WREF 2012 22
Thank you for your attention Per Ekdunge WREF 2012 Property of PowerCell Sweden AB 23