Gas ejector design calculation
Journal of Power Sources 277 (2015) 251e260Ībbreviations A AC D DC m n O/C p RR SOFC T uĪrea alternating current diameter direct current mass flow rate molar flow rate oxygen-to-carbon ratio pressure recirculation ratio solid oxide fuel cell temperature velocityĪchieved an efficiency of 41%. demonstrated a 300 W SOFC system with anode off-gas recirculation running on a propane-driven ejector. This system has a power output of 7.1 kW and uses a high-temperature blower for recirculation. presented an SOFC system with an electrical efficiency of 43%. Their SOFC module operates at a DC efficiency of 64%. Versa Power Systems and FuelCell Energy have built an SOFC system with a high-temperature blower that handles gas temperatures of up to 700 C. With this AVL's SOFC system reaches an electrical efficiency of around 50%. The blower rotates at 120,000 rpm and has an efficiency of 50%. AVL developed and manufactured a high-temperature prototype blower that operates at a maximum gas temperature of 600 C. The most frequently chosen concepts for driving anode off-gas recirculation systems are the use of blowers and ejectors. Their results show that electrical efficiency is up to 16% lower in systems with no anode off-gas recirculation. compared different concepts with and without anode off-gas recirculation. The recirculation of anode off-gas is one method of achieving a large efficiency jump as it improves system fuel utilization. To increase the initial efficiencies, improvements have been made on the cell and system levels, increasing efficiencies up to 60%. SOFCs are hightemperature fuel cell technologies and have been under development for a number of years. As our natural resources are limited, highly efficient energy systems, such as solid oxide fuel cell (SOFC) systems, are needed. Introduction Global energy consumption is growing day by day. Keywords: Fuel cells SOFC Anode recycling Steam ejector Fuel ejector Part loadġ. Here, the minimal part load was determined by the condensation temperature of the condenser used in the system. The simulation results for this system showed an improved part-load capability of 37.8% as well as a slightly improved electrical efficiency. The second system was based on a steam-driven ejector. The part-load threshold of this system was determined by carbon formation and was 77.8% assuming a fuel utilization of 70% and suitable ejector geometry. In the first system, recirculation was enabled by a fueldriven ejector. This paper investigates the use of ejectors for recirculating anode off-gas in an SOFC system, focusing on the part-load capability of two different systems. A steam driven concept increases the electrical efficiency.Īrticle history: Received Received in revised form 27 November 2014 Accepted 3 December 2014 Available online 5 December 2014
The condensation temperature limits the part load of a steam driven ejector system.
Carbon formation limits the part load of a fuel driven ejector system. A steam and fuel driven ejector are used for recirculation. H i g h l i g h t s We model an SOFC system with anode off-gas recirculation. Journal of Power Sources journal homepage: Comparison of a fuel-driven and steam-driven ejector in solid oxide fuel cell systems with anode off-gas recirculation: Part-load behavior Maximilian Engelbracht*, Roland Peters, Ludger Blum, Detlef Stolten Forschungszentrum Jülich GmbH, Institute of Energy and Climate Research (IEK-3), Electrochemical Process Engineering, Wilhelm-Johnen-Straße, 52425 Jülich, Germany Journal of Power Sources 277 (2015) 251e260Ĭontents lists available at ScienceDirect