426 results found
Cai Q, Brandon NP, Adjiman CS, 2010, Modelling the dynamic response of a solid oxide steam electrolyser to transient inputs during renewable hydrogen production, Frontiers of Energy and Power Engineering in China, Vol: 4, Pages: 211-222, ISSN: 1673-7504
Hydrogen is regarded as a leading candidate for alternative future fuels. Solid oxide electrolyser cells (SOEC) may provide a cost-effective and green route to hydrogen production especially when coupled to a source of renewable electrical energy. Developing an understanding of the response of the SOEC stack to transient events that may occur during its operation with intermittent electricity input is essential before the realisation of this technology. In this paper, a one-dimensional (1D) dynamic model of a planar SOEC stack has been employed to study the dynamic behaviour of such an SOEC and the prospect for stack temperature control through variation of the air flow rate. Step changes in the average current density from 1.0 to 0.75, 0.5 and 0.2 A/cm2 have been imposed on the stacks, replicating the situation in which changes in the supply of input electrical energy are experienced, or the sudden switch-off of the stack. Such simulations have been performed both for open-loop and closed-loop cases. The stack temperature and cell voltage are decreased by step changes in the average current density. Without temperature control via variation of the air flow rate, a sudden fall of the temperature and the cell potential occurs during all the step changes in average current density. The temperature excursions between the initial and final steady states are observed to be reduced by the manipulation of the air flow rate. Provided that the change in the average current density does not result in a transition from exothermic to endothermic operation of the SOEC, the use of the air flow rate to maintain a constant steady-state temperature is found to be successful.
Brandon NP, 2010, Understanding solid oxide fuel cell microstructure, ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, Vol: 239, ISSN: 0065-7727
Shearing PR, Howard LE, Jorgensen PS, et al., 2010, Characterization of the 3-dimensional microstructure of a graphite negative electrode from a Li-ion battery, ELECTROCHEMISTRY COMMUNICATIONS, Vol: 12, Pages: 374-377, ISSN: 1388-2481
Mermelstein J, Millan M, Brandon N, 2010, The impact of steam and current density on carbon formation from biomass gasification tar on Ni/YSZ, and Ni/CGO solid oxide fuel cell anodes, Journal Power Sources, Vol: 195, Pages: 1657-1666
Brandon NP, Matian M, Marquis AJ, et al., 2010, THERMAL MANAGEMENT ISSUES IN FUEL CELL TECHNOLOGY, 14th International Heat Transfer Conference, Publisher: AMER SOC MECHANICAL ENGINEERS, Pages: 591-599
Maher RC, Brightman E, Heck C, et al., 2010, Monitoring Solid Oxide Fuel Cell Processes Using In-Situ Raman Spectroscopy, 22nd International Conference on Raman Spectroscopy, Publisher: AMER INST PHYSICS, Pages: 550-550, ISSN: 0094-243X
Diomampo GP, Roach H, Chapin M, et al., 2010, Integrated dynamic reservoir modeling for multilayered tight gas sand development, Pages: 1065-1080
This paper summarizes the approach used for applying integrated reservoir modeling to the tight gas sands of the Pinedale Anticline in western Wyoming. The simulation of tight gas sands such as those at Pinedale has always been challenging because of the high degree of heterogeneity that needs to be retained to replicate reservoir performance, coupled with computing constraints. Added to this, simulating the Pinedale reservoir has its own unique challenges due to its characteristically thick gross sand interval composed of multiple, heterogeneous sand bodies produced commingled in a well. An intensive data-gathering program to investigate optimum well spacing accompanied the simulation effort. A significant part of this program was the installation of pressure monitor wells1 to detect communication with surrounding producers at the hydraulic fracture stage level. This was coupled with multiple time-lapse production logs. The two data sets together allowed better definition of stage performance at producing wells. Static models were built with fine resolution to duplicate reservoir heterogeneity. However, upscaling was necessary due to computing constraints. The upscaling procedure of Li and Beckner2 was utilized to maintain substantial geologic heterogeneity. The upscaled model was calibrated to mimic fine scale well performance prior to history matching. Several sector upscale models were history matched using a statistical approach without compromising key aspects such as reservoir connectivity and proper mass withdrawal from each geologic sub layer. Hydraulic fractures in each stage were characterized through history matching. Given the geostatistical nature, an exact match on every frac stage and every pressure gauge located away from the producer should not be expected. Rather, a more statistical definition of a history match should be adapted to a level that still gives confidence in forecasting the value of future infill wells. The history-matched parameters
Zhao Y, Shah N, Brandon N, 2010, Performance investigation of a SOFC-GT hybrid system based on thermodynamic optimization strategies, Proceedings of the 23rd International Conference on Efficiency, Cost, Optimization, Simulation, and Environmental Impact of Energy Systems, ECOS 2010, Vol: 5, Pages: 9-16
A thermodynamic optimization methodology is developed to model, analyze, and predict the system behaviour of a combined SOFC-GT cycle. The system efficiency and power output are used as a basis to optimize the whole hybrid power plant. The optimized performance characteristics are presented and discussed in detail through a parametric analysis. Simulations of the effects that various design and operating parameters have on system performance have led to some interesting results. This study can be considered as a preliminary investigation of more complex fuel cell and gas turbine hybrid systems incorporating additional practical irreversible losses.
Offer GJ, Howey DA, Contestabile M, et al., 2010, Comparative analysis of battery electric, hydrogen fuel cell and hybrid vehicles in a future sustainable road transport system, Energy Policy, Vol: 38, Pages: 24-29
This paper compares battery electric vehicles (BEV) to hydrogen fuel cell electric vehicles (FCEV) and hydrogen fuel cell plug-in hybrid vehicles (FCHEV). Qualitative comparisons of technologies and infrastructural requirements, and quantitative comparisons of the lifecycle cost of the powertrain over 100,000 mile are undertaken, accounting for capital and fuel costs. A common vehicle platform is assumed. The 2030 scenario is discussed and compared to a conventional gasoline-fuelled internal combustion engine (ICE) powertrain. A comprehensive sensitivity analysis shows that in 2030 FCEVs could achieve lifecycle cost parity with conventional gasoline vehicles. However, both the BEV and FCHEV have significantly lower lifecycle costs. In the 2030 scenario, powertrain lifecycle costs of FCEVs range from $7360 to $22,580, whereas those for BEVs range from $6460 to $11,420 and FCHEVs, from $4310 to $12,540. All vehicle platforms exhibit significant cost sensitivity to powertrain capital cost. The BEV and FCHEV are relatively insensitive to electricity costs but the FCHEV and FCV are sensitive to hydrogen cost. The BEV and FCHEV are reasonably similar in lifecycle cost and one may offer an advantage over the other depending on driving patterns. A key conclusion is that the best path for future development of FCEVs is the FCHEV.
Brett DJL, Kucernak AR, Aguiar P, et al., 2010, What happens inside a fuel cell? Developing an experimental functional map of fuel cell performance, ChemPhysChem, Vol: 11, Pages: 2714-2731
Matian M, Marquis A, Brett D, et al., 2010, An experimentally validated heat transfer model for thermal management design in polymer electrolyte membrane fuel cells, Journal of Power and Energy
Panos C, Kouramas KI, Georgiadis MC, et al., 2010, Modelling and Explicit MPC of PEM Fuel Cell Systems, Computer Aided Chemical Engineering, Vol: 28, Pages: 517-522
Cordner M, Matian M, Offer GJ, et al., 2010, Designing, building, testing and racing a low-cost fuel cell range extender for a motorsport application, Journal of Power Sources
Cai Q, Adjiman CS, Brandon NP, 2010, Modelling the dynamic response of a solid oxide steam electrolyser to transient inputs during renewable hydrogen production, Frontiers of Energy and Power Engineering in China, Vol: 4, Pages: 211-222
Sadhukhan J, Zhao Y, Shah N, et al., 2010, Performance analysis of integrated biomass gasification fuel cell (BGFC) and biomass gasification combined cycle (BGCC) systems, Chemical Engineering Science, Vol: 65, Pages: 1942-1954
Biomass gasification processes are more commonly integrated to gas turbine based combined heat and power (CHP) generation systems. However, efficiency can be greatly enhanced by the use of more advanced power generation technology such as solid oxide fuel cells (SOFC). The key objective of this work is to develop systematic site-wide process integration strategies, based on detailed process simulation in Aspen Plus, in view to improve heat recovery including waste heat, energy efficiency and cleaner operation, of biomass gasification fuel cell (BGFC) systems. The BGFC system considers integration of the exhaust gas as a source of steam and unreacted fuel from the SOFC to the steam gasifier, utilising biomass volatilised gases and tars, which is separately carried out from the combustion of the remaining char of the biomass in the presence of depleted air from the SOFC. The high grade process heat is utilised into direct heating of the process streams, e.g. heating of the syngas feed to the SOFC after cooling, condensation and ultra-cleaning with the Rectisol® process, using the hot product gas from the steam gasifier and heating of air to the SOFC using exhaust gas from the char combustor. The medium to low grade process heat is extracted into excess steam and hot water generation from the BGFC site. This study presents a comprehensive comparison of energetic and emission performances between BGFC and biomass gasification combined cycle (BGCC) systems, based on a 4th generation biomass waste resource, straws. The former integrated system provides as much as twice the power, than the latter. Furthermore, the performance of the integrated BGFC system is thoroughly analysed for a range of power generations, 100–997 kW. Increasing power generation from a BGFC system decreases its power generation efficiency (69–63%), while increasing CHP generation efficiency (80–85%).
Zhao Y, Shah N, Brandon NP, 2010, The Development and Application of a Novel Optimisation Strategy for Solid Oxide Fuel Cell-Gas Turbine Hybrid Cycles, Fuel Cells, Vol: 10, Pages: 181-193
A combined power system with solid oxide fuel cell (SOFC) and gas turbine (GT) is modelled and analysed thermodynamically in this paper. A novel optimisation strategy including the design of optimal parameters is proposed and applied to the hybrid system. Different sources of irreversible losses are specified, and entropy analyses are used to indicate the multi-irreversibilities existing, and to assess the work potentials of the system. Expressions of the power output and efficiency for both the subsystems and the SOFC-GT hybrid system are derived. The optimal performance characteristics are presented and discussed in detail through a parametric analysis. The developed model is expected to provide not only a convenient tool to determine the optimal system performance and component irreversibility, but also an appropriate basis to design similar complex hybrid power plants. This new approach can be further extended to other energy conversion settings and electrochemical systems. Decision makers should therefore find the methodology contained in this paper useful in the comparison and selection of advanced heat recovery systems.
Matian M, Marquis A, Brandon NP, 2010, Application of thermal imaging to validate a heat transfer model for polymer electrolyte fuel cells, Int. Journal of Hydrogen Energy
Mermelstein J, Millan-Agorio M, Brandon NP, 2009, The impact and mitigation of carbon formation on Ni-YSZ anodes from biomass gasification tars, Pages: 111-117, ISSN: 1938-5862
The combination of Solid Oxide Fuel Cells (SOFCs) and biomass gasification has the potential to become an attractive technology for the production of clean renewable energy. However the impact of tars, formed during biomass gasification, on the performance and durability of SOFC anodes has not been well established experimentally. This paper reports on an experimental study assessment of the performance and mitigation of carbon formation on the anodes of SOFC button cells from synthetic model tars arising from the gasification of biomass material. The anode material was a 60:40 wt.% NiO/YSZ cermet, which was tested in a synthetically generated syngas containing a concentration of up to 15 g/Nm3 biomass gasification tars. It was found that carbon formation in dry conditions significantly damaged the anode of the fuel cell resulting in decreased cell performance and excessive anode polarization resistances. These effects were reduced by applying a load to the cell, and were essentially inhibited once the steam content of the input fuel was > 2%. © The Electrochemical Society.
Clague R, Offer G, Matian M, et al., 2009, Fuel cell racing: Imperial College London presents the Racing Green team, Pages: 302-311
Imperial Racing Green is a major initiative at Imperial College London to design, build and race zero emission vehicles in order to give students hands-on experience in the design, development and construction of fuel cell and battery vehicles, and win competitions like Formula Zero and Formula Student Class 1A, run by the Institute of Mechanical Engineers. The former competition is a time trial series for fuel cell go-carts, the latter is for single seat race cars and accommodates a wider range of technologies. The Imperial Racing Green entry to Formula Zero, codenamed IRG02, is a go-cart powered by a Hydrogenics 8kW PEM fuel cell coupled via a DC/DC converter in a current control loop to two banks of 165F Maxwell ultra-capacitors. Overall vehicle control is achieved with a National Instruments CompactRio, which also acts as a data logger. The Imperial Racing Green entry to Formula Student Class 1A, codenamed IRG03, has a modular 25kW electric drive, braking and suspension assembly at each corner. Racing Green will continue to compete in the Formula Zero Championship throughout 2009, and will compete in Formula Student Class 1A at Silverstone in July 2009. This project has demonstrated that new approaches to project based learning can generate enormous student interest and international media attention, while being rewarding to the academics and researchers involved too. This paper gives detailed information of the design of IRG02 and presents data recorded during the Formula Zero race of August 2008. A summary of the design of IRG03 is also given, concluding with lessons learnt and future plans.
Shearing PR, Gelb J, Brandon NP, 2009, Characterization of SOFC electrode microstructure using nano-scale X-ray Computed Tomography and Focused Ion Beam techniques: A comparative study, Pages: 51-57, ISSN: 1938-5862
In solid oxide fuel cells (SOFC) the redox reactions are supported by composite porous materials and, therefore, the electrochemical activity of an electrode is a direct function of its microstructure. Ni-YSZ (Yttria Stabilized Zirconia) is a common choice for the anode material in SOFC. Recently advances in tomographic techniques have enabled researchers to probe electrode microstructures providing unprecedented access to a wealth of microstructural information regarding the distribution of ionic, electronic and pore phases in three dimensions. In this paper nano-scale X-ray Computed Tomography (nCT) and Focused Ion Beam (FIB) techniques have been used to characterize microstructures from the same Ni-YSZ anode sample, 3D reconstruction from both techniques are presented and a quantitative and qualitative comparison is provided. An advanced technique for sample preparation for nCT is also presented. ©The Electrochemical Society.
Hawkes AD, Brett DL, Brandon NP, 2009, Fuel Cell Micro-CHP Techno-Economics: Part 2 – Model Application to Consider the Economic and Environmental Impact of Stack Degradation, International Journal of Hydrogen Energy, Vol: In Press
Hawkes AD, Brett DL, Brandon NP, 2009, Fuel Cell Micro-CHP Techno-Economics: Part 1 - Model Concept and Formulation, International Journal of Hydrogen Energy, Vol: In Press
Mermelstein J, Brandon N, Millan M, 2009, Impact of Steam on the Interaction between Biomass Gasification Tars and Nickel-Based Solid Oxide Fuel Cell Anode Materials, ENERGY & FUELS, Vol: 23, Pages: 5042-5048, ISSN: 0887-0624
Shearing PR, Golbert J, Chater RJ, et al., 2009, 3D reconstruction of SOFC anodes using a focused ion beam lift-out technique, CHEMICAL ENGINEERING SCIENCE, Vol: 64, Pages: 3928-3933, ISSN: 0009-2509
Bidault F, Brett DJL, Middleton PH, et al., 2009, A new application for nickel foam in alkaline fuel cells, 4th Dubrovnik Conference on Sustainable Development of Energy, Water and Environment Systems, Publisher: PERGAMON-ELSEVIER SCIENCE LTD, Pages: 6799-6808, ISSN: 0360-3199
Lorente E, Cai Q, Pena JA, et al., 2009, Conceptual design and modelling of the Steam-Iron process and fuel cell integrated system, INT J HYDROGEN ENERG, Vol: 34, Pages: 5554-5562, ISSN: 0360-3199
The Steam-Iron process, based on the redox reaction of iron oxides (Fe3O4 + 4H(2) <-> 3Fe+4H(2)O), is an interesting alternative to other methods of storing and generating pure hydrogen. In order to evaluate the ability of the Steam-Iron process to supply hydrogen to a solid oxide fuel cell (SOFC), a mathematical model for the oxidation process in a fixed bed reactor has been developed and is used to estimate the behaviour of the reactor under various operating conditions (e.g. amount of iron, steam flow rate, temperature). As a result of the simulations, information is provided for the preliminary design of the reactor and the selection of optimal reaction conditions. Furthermore, we have shown that the Steam-Iron reactor can be successfully integrated with an SOFC, and two system options have been explored to determine the overall system efficiency. (C) 2009 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.
Offer GJ, Brandon NP, 2009, The effect of current density and temperature on the degradation of nickel cermet electrodes by carbon monoxide in solid oxide fuel cells, CHEMICAL ENGINEERING SCIENCE, Vol: 64, Pages: 2291-2300, ISSN: 0009-2509
Kim P, Brett DJL, Brandon NP, 2009, The effect of water content on the electrochemical impedance response and microstructure of Ni-CGO anodes for solid oxide fuel cells, JOURNAL OF POWER SOURCES, Vol: 189, Pages: 1060-1065, ISSN: 0378-7753
Offer GJ, Mermelstein J, Brightman E, et al., 2009, Thermodynamics and Kinetics of the Interaction of Carbon and Sulfur with Solid Oxide fuel Cell Anodes, JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Vol: 92, Pages: 763-780, ISSN: 0002-7820
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