VTT TECHNICAL RESEARCH CENTRE OF FINLAND LTD Development of Reformed Ethanol Fuel Cell System for Backup and Off-Grid Applications Anode gas recirculation with an ejector 26-27 th of October, HFC Nordic 2016, Sandviken, Sweden Kaj Nikiforow VTT Technical Research Centre of Finland Ltd
Outline 1. VTT 2. PEMBeyond-project 3. Anode gas recirculation with ejector 4. Summary 2
VTT 3
VTT Technical Research Centre of Finland Ltd The leading research and technology company in the Nordic countries with over 70 years of experience A Finnish national institution with non-profit status Provides expert services for both domestic and international partners on both private and public sectors Ideology focus: New smart technologies for profitable solutions Innovation in co-operation with our customers Produce technology for business Build success and well-being to benefit of society Turnover 185 M, personnel ~2500 Finland 4
VTT Fuel Cells & H 2 The main research areas FC & H 2 Performance analysis Model-based solutions Stack solutions Hydrogen fuel quality Intelligent fuel cell systems System technology services Concepts and technology evaluation 5
PEMBeyond-project
PEMBeyond - Developing a crude bioethanol fueled power system Development of an integrated PEFC based power system for stationary backup and off-grid power generation Using crude (80-95%) bioethanol as primary fuel Cost-competitive (complete system < 2 500 /kw @ 500 units) Energy-efficient (> 30% overall system efficiency) Durable (> 20 000 h system lifetime in continuous operation) Extensive laboratory testing and limited field trial (~1000 h) Seeking ways to commercialize the concept for market entry Project volume 4.6 M total budget / 378 person-months total 3.5 years, May 2014 October 2017 Funded by European Union and Fuel Cells and Hydrogen Joint Undertaking GA n 621218 7
Reformed Ethanol Fuel Cell System (REFCS) 8
Ejector based anode gas recirculation
Anode gas recirculation - background Anode gas recirculation improves fuel cell performance by humidifying anode inlet gas increasing flow velocity (e.g. prevents water droplet formation) Mechanical pumps are traditionally employed Pressurized H 2 Pressure reducer Pump PEMFC Purge/bleed valve Ejectors improve durability cost-competitiveness energy-efficiency Pressurized H 2 Pressure reducer Ejector PEMFC Purge/bleed valve 10
Ejector studies at VTT Custom-made ejector for 5 kw PEMFC 1 Ejector modeling (CFD, thermodynamic approach) Ejector characterization (dry/humid, air/h 2 ) ~7 cm Ejector efficiency [%] map Fuel utilization per pass [%] map 1 Nikiforow & al., Int. J. Hydrogen Energy, 41 (2016), pp. 14952 14970 11
Ejector control Ejector primary flow rate must equal H 2 consumption rate depends on primary inlet pressure Many pressure control devices are expensive Primary inlet (high pressure) Secondary inlet (suction inlet) Outlet Target: cost-effective ejector control approach Stationary systems can be operated at discrete power levels (e.g. the REFCS operates only at 2 kw or at 5 kw) 12
Ejector control one approach A combination of static flow restrictions and solenoid valves allows operation at discrete points Idea: restrict the flow rate (not the pressure) 3 restrictions result in 7 combinations p = 10 barg Valve 1 Restriction 1 Valve 2 Restriction 2 Valve 3 Restriction 3 p = f (V H2) 13
Summary
Summary Crude bioethanol fueled PEM fuel cell based back-up power system is developed Ejector offers reliable anode gas recirculation with high energy-efficiency and at low cost Simple and cost effective ejector inlet pressure control method is studied 15
Acknowledgement The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) for the Fuel Cells and Hydrogen Joint Technology Initiative under grant agreement n 621218. 16
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