Solid Oxide Fuel Based Auxiliary Power Unit for Regional Jets: Design and Mission Simulation With Different Cell Geometries

2010 ◽  
Vol 7 (2) ◽  
Author(s):  
M. Santarelli ◽  
M. Cabrera ◽  
M. Calì
Keyword(s):  
Fuel Cell ◽  
Urban Areas ◽  
Energy System ◽  
High Energy ◽  
Low Noise ◽  
Solid Oxide ◽  
High Energy Density ◽  
Oxide Fuel ◽  
Balance Of Plant ◽  
Compressor Power

Although it accounts for only 4.2% of the total global warming potential, the concern today is that aviation generated CO2 is projected to grow to approximately 5.7% by 2050. Aviation emissions are growing faster than any other sector and they risk undermining the progress achieved through emission cuts in other areas of the economy. Rapidly emerging hydrogen and fuel-cell-based technologies could be developed for future replacement of on-board electrical systems in “more-electric” or “all-electric” aircrafts. Primary advantages of deploying these technologies are low emissions and low noise (important features for commuter airplanes, which takeoff and land in urban areas). Solid oxide fuel-cell (SOFC) systems could result advantageous for some aeronautical applications due to their capability of accepting hydrocarbons and high energy-density fuels. Moreover they are suitable for operating in combined-heat-and-power configurations, recovering heat from the high-temperature exhaust gases, which could be used to supply thermal loads therefore reducing the electric power requested by the aircraft. ENFICA-FC is a project selected by the European Commission in the Aeronautics and Space priority of the Sixth Framework Programme (FP6) and led by Politecnico di Torino, in Turin, Italy. One of the objectives of the project is to carry out a feasibility study on a more-electric intercity aircraft (regional jet: 32 seats). After the characterization of the power consumption of electrical and nonelectrical loads, and the definition of a mission profile, the design of the SOFC-based energy system as well as the simulation of a complete mission is performed hypothesizing different system configurations. The simulation concerns both the stack (current and current density, cell and stack voltage, etc.) and the balance-of-plant (air compressor power, gross stack power, system efficiency, etc.). The obtained results are analyzed and discussed.

Highly Efficient Conversion of Ammonia in Electricity by Solid Oxide Fuel Cells

2006 ◽  
Vol 3 (4) ◽  
pp. 499-502 ◽  
Author(s):  
N. J. J. Dekker ◽  
G. Rietveld
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Energy Density ◽  
High Pressures ◽  
Cell Voltage ◽  
Electrical Current ◽  
High Energy ◽  
Solid Oxide ◽  
High Energy Density ◽  
Oxide Fuel

Hydrogen is the fuel for fuel cells with the highest cell voltage. A drawback for the use of hydrogen is the low energy density storage capacity, even at high pressures. Liquid fuels such as gasoline and methanol have a high energy density but lead to the emission of the greenhouse gas CO2. Ammonia could be the ideal bridge fuel, having a high energy density at relative low pressure and no (local) CO2 emission. Ammonia as a fuel for the solid oxide fuel cell (SOFC) appears to be very attractive, as shown by cell tests with electrolyte supported cells (ESC) as well as anode supported cells (ASC) with an active area of 81cm2. The cell voltage was measured as function of the electrical current, temperature, gas composition and ammonia (NH3) flow. With NH3 as fuel, electrical cell efficiencies up to 70% (LHV) can be achieved at 0.35A∕cm2 and 60% (LHV) at 0.6A∕cm2. The cell degradation during 3000 h of operation was comparable with H2 fueled measurements. Due to the high temperature and the catalytic active Ni∕YSZ anode, NH3 cracks at the anode into H2 and N2 with a conversion of >99.996%. The high NH3 conversion is partly due to the withdrawal of H2 by the electrochemical cell reaction. The remaining NH3 will be converted in the afterburner of the system. The NOx outlet concentration of the fuel cell is low, typically <0.5ppm at temperatures below 950°C and around 4ppm at 1000°C. A SOFC system fueled with ammonia is relative simple compared with a carbon containing fuel, since no humidification of the fuel is necessary. Moreover, the endothermic ammonia cracking reaction consumes part of the heat produced by the fuel cell, by which less cathode cooling air is required compared with H2 fueled systems. Therefore, the system for a NH3 fueled SOFC will have relatively low parasitic power losses and relative small heat exchangers for preheating the cathode air flow.

Effect of Anode-Off Gas Recirculation at Solid Oxide Fuel Cell System

2008 ◽  
Author(s):  
Seugnwhan Baek ◽  
Yongmin Kim ◽  
Joongmyeon Bae
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
High Energy ◽  
Cell System ◽  
Solid Oxide ◽  
High Energy Density ◽  
Total Efficiency ◽  
Oxide Fuel ◽  
Fuel Cell System ◽  
Diesel Reformer

The aim of this work is to analyze system efficiency when anode-off gases are recirculated at a diesel driven solid oxide fuel cell system. Diesel was chosen as a fuel due to advantages of its high energy density and well-established infrastructure. Three systems were mainly investigated which have different system configurations. First system does not use recirculation of anode-off gas at the system. At second model anode-off gases are recirculated to a diesel reformer in the system. Finally anode-off gases are recirculated to the anode side of a solid oxide fuel cell stack. Three different systems are compared in terms of total efficiency, performances of diesel reformer and solid oxide fuel cell. It was found that various inlet conditions and split conditions would make differences of total efficiencies and component performances at the three different systems.

Surge Prevention Techniques for a Turbocharged Solid Oxide Fuel Cell Hybrid System

2021 ◽  
Author(s):  
L. Mantelli ◽  
M. L. Ferrari ◽  
A. Traverso
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Rotational Speed ◽  
Pressure Ratio ◽  
High Energy ◽  
Cell System ◽  
Solid Oxide ◽  
Pollutant Emissions ◽  
Inlet Temperature ◽  
Oxide Fuel

Abstract Pressurized solid oxide fuel cell (SOFC) systems are one of the most promising technologies to achieve high energy conversion efficiencies and reduce pollutant emissions. The most common solution for pressurization is the integration with a micro gas turbine, a device capable of exploiting the residual energy of the exhaust gas to compress the fuel cell air intake and, at the same time, generating additional electrical power. The focus of this study is on an alternative layout, based on an automotive turbocharger, which has been more recently considered by the research community to improve cost effectiveness at small size (&lt; 100 kW), despite reducing slightly the top achievable performance. Such turbocharged SOFC system poses two main challenges. On one side, the absence of an electrical generator does not allow the direct control of the rotational speed, which is determined by the power balance between turbine and compressor. On the other side, the presence of a large volume between compressor and turbine, due to the fuel cell stack, alters the dynamic behavior of the turbocharger during transients, increasing the risk of compressor surge. The pressure oscillations associated with such event are particularly detrimental for the system, because they could easily damage the materials of the fuel cells. The aim of this paper is to investigate different techniques to drive the operative point of the compressor far from the surge condition when needed, reducing the risks related to transients and increasing its reliability. By means of a system dynamic model, developed using the TRANSEO simulation tool by TPG, the effect of different anti-surge solutions is simulated: (i) intake air conditioning, (ii) water spray at compressor inlet, (iii) air bleed and recirculation, and (iv) installation of an ejector at the compressor intake. The pressurized fuel cell system is simulated with two different control strategies, i.e. constant fuel mass flow and constant turbine inlet temperature. Different solutions are evaluated based on surge margin behavior, both in the short and long terms, but also monitoring other relevant physical quantities of the system, such as compressor pressure ratio and turbocharger rotational speed.

System Configuration and Performance Studies of Solid Oxide Fuel Cell -Gas Turbine Hybrid Cycle

2007 ◽  
Author(s):  
Wei Jiang ◽  
Ruxian Fang ◽  
Jamil A. Khan ◽  
Roger A. Dougal
Keyword(s):  
Fuel Cell ◽  
Power Plant ◽  
Solid Oxide Fuel Cell ◽  
Gas Turbine ◽  
Finite Volume ◽  
Hybrid System ◽  
High Energy ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Hybrid Cycle

Fuel Cell is widely regarded as a potential alternative in the electric utility due to its distinct advantages of high energy conversion efficiency, low environmental impact and flexible uses of fuel types. In this paper we demonstrate the enhancement of thermal efficiency and power density of the power plant system by incorporating a hybrid cycle of Solid Oxide Fuel Cell (SOFC) and gas turbine with appropriate configurations. In this paper, a hybrid system composed of SOFC, gas turbine, compressor and high temperature heat exchanger is developed and simulated in the Virtual Test Bed (VTB) computational environment. The one-dimensional tubular SOFC model is based on the electrochemical and thermal modeling, accounting for the voltage losses and temperature dynamics. The single cell is discretized using a finite volume method where all the governing equations are solved for each finite volume. Simulation results show that the SOFC-GT hybrid system could achieve a 70% total electrical efficiency (LHV) and an electrical power output of 853KW, around 30% of which is produced by the power turbine. Two conventional power plant systems, i.e. gas turbine recuperative cycle and pure Fuel Cell power cycle, are also simulated for the performance comparison to validate the improved performance of Fuel Cell/Gas Turbine hybrid system. Finally, the dynamic behavior of the hybrid system is presented and analyzed based on the system simulation.

Design and Balance-of-Plant of a Demonstration Plant With a Solid Oxide Fuel Cell Fed by Biogas From Waste-Water and Exhaust Carbon Recycling for Algae Growth

2013 ◽  
Author(s):  
M. Gandiglio ◽  
A. Lanzini ◽  
P. Leone ◽  
M. Santarelli
Keyword(s):  
Waste Water ◽  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Treatment Plant ◽  
Solid Oxide ◽  
Waste Water Treatment Plant ◽  
Oxide Fuel ◽  
Balance Of Plant ◽  
Outlet Stream ◽  
Demonstration Plant

The design and balance-of-plant of an integrated anaerobic digestion (AD) biogas solid oxide fuel cell (SOFC) demonstration plant is presented. A notable feature of the plant is the CO2 capture from the SOFC anode exhaust via an oxy-combustion reactor. The captured CO2 is fed to a photobioreactor installation downstream of the SOFC where C is fixed in an algae bio-fuel. The main plant sections are described in detail including the gas cleaning unit, fuel processing, SOFC ‘hot-box’, oxy-combustor, CO2/H2O condensation unit and finally algae bioreactor. The demonstration plant is fed with biogas from AD of the by-product sludge of the greatest waste-water treatment plant in Italy, serving over 2 million population equivalents in the Torino metropolitan area. In this work, the main BoP components and engineering issues concerning the design of the SOFC plant are detailed. The as-produced biogas is firstly treated to remove moisture and then filtered to remove sulfur, halogens and siloxanes. Dry clean biogas (roughly 60–65% CH4, 35–40% CO2) is sent to a steam-reformer. The reformate gas is thus used to feed a 2 kWe SOFC module (operated at ∼ 800 °C). The cathode off-gas is kept separated from the anode and is used to pre-heat inlet fresh air; the anode outlet stream is sent first to an oxy-combustor to yield an almost pure H2O-CO2 mixture that is eventually cooled down to 300–400 °C. Steam is condensed and separated in a dedicated condenser unit. The resulting pure CO2 is thus pressurized (8 bar) and available for sequestration or other uses. Due to the limited size of the demo plant, the choice was to feed it to bioreactors with algae, where the latter are grown with sunlight and CO2 indeed. A tubular photo-bioreactor has been chosen with a productivity of 20 g/day/m2 of dry algae. The outlet stream will be an algae purge that, due to its low mass flow, could be re-sent to the biogas digesters. A system analysis of a scaled-up version of the biogas fed SOFC power plant, with heat integration included, is also carried out with a calculated overall electrical efficiency exceeding 55% (LHV basis).

scholarly journals Ammonia-based Solid Oxide Fuel Cell for zero emission maritime power: a case study

2022 ◽  
Vol 334 ◽  
pp. 06007
Author(s):  
Simona Di Micco ◽  
Mariagiovanna Minutillo ◽  
Luca Mastropasqua ◽  
Viviana Cigolotti ◽  
Jack Brouwer
Keyword(s):  
Fuel Cell ◽  
Diesel Engine ◽  
Solid Oxide Fuel Cell ◽  
High Energy ◽  
Propulsion System ◽  
Solid Oxide ◽  
Pollutant Emissions ◽  
Optimal Size ◽  
Oxide Fuel ◽  
Heavy Fuel Oil

Implementing environmentally friendly fuels and high efficiency propulsion technologies to replace the Internal Combustion Engine (ICE) fueled by fossil fuels such as Heavy Fuel Oil (HFO) and Marine Gas Oil (MGO) on board ships represents an attractive solution for maritime power. In this context, fuel cells can play a crucial role, thanks to their high energy efficiency and ultra-low to zero criteria pollutant emissions and environmental impact. This paper performs the technical feasibility analysis for replacing the conventional diesel engine powertrain on board a commercial vessel with an innovative system consisting of ammonia-fuel-based Solid Oxide Fuel Cell (SOFC) technology. Taking into account the size of the diesel engines installed on board and the typical cruise performed by the commercial vessel, the ammonia consumption, as well as the optimal size of the innovative propulsion system have been assessed. In particular, the SOFC powertrain is sized at the same maximum power output as the main reference diesel engine. The mass and energy balances of the ammonia-based SOFC system have been performed in Aspen PlusTM environment. The gravimetric (kWh kg−1) and volumetric (kWh m−3) energy density features of the ammonia storage technology as well as the weight and volume of the proposed propulsion system are evaluated for verifying the compliance with the ship’s weight and space requirements. Results highlight that the proposed propulsion system involves an increase in weight both in the engine room and in the fuel room compared to the diesel engine and fuel. In particular, a cargo reduction of about 2.88% is necessary to fit the ammonia-based SOFC system compared to the space available in the reference diesel-fueled ship.

Understanding Transport and Reaction Processes in the Solid Oxide Fuel Cell Anode at Sub-50 nm Resolution

2008 ◽  
Author(s):  
John R. Izzo ◽  
Abhijit S. Joshi ◽  
Kyle N. Grew ◽  
Wilson K. S. Chiu
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
High Energy ◽  
Solid Oxide ◽  
Great Promise ◽  
Oxide Fuel ◽  
Pore Scale ◽  
Continue Development ◽  
Reaction Processes ◽  
Fuel Cell Anode

The Solid Oxide Fuel Cell (SOFC) holds great promise for a variety of portable power based applications because of the fuel flexibility and gravimetric power densities that it can maintain. These advantages are a product of the SOFC’s ability to directly use a wide variety of hydrocarbon based fuels that maintain high energy densities and are relatively easy to store. Models can be developed to describe the operation of SOFCs, where the pore structure is described with idealized structures or quantified with parameters. However, there are discrepancies in fundamental descriptions within these models resulting from a lack of a fundamental understanding of the physics of the associated pore scale processes. To continue development efforts, an improved understanding of the role of the anode microstructure at the pore scale and below is required. This paper will review our effort to develop such an understanding through anode structure reconstruction and characterization using non-destructive high resolution x-ray computed tomography (XCT).

Solid Oxide Fuel Cell - A Key Technology for a Highly Efficient Energy System

MTZ worldwide ◽  
2021 ◽  
Vol 82 (5-6) ◽  
pp. 58-63
Author(s):  
Martin Hauth ◽  
Dirk Becker ◽  
Jürgen Rechberger
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Energy System ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Key Technology ◽  
Efficient Energy ◽  
Highly Efficient
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