IFE Brage (Institute for Energy Technology)
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Combination of a millimeter scale reactor and gas chromatography-mass spectrometry for mapping higher order silane formation during monosilane pyrolysis
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Corrosion of candidate materials for use in alkaline water electrolysis
Get PDFIn alkaline water electrolysis the capital expense (CAPEX) of the electrolyzer unit is high and cost reduction, wherever possible, is highly desired. Many parts are made of expensive nickel-based alloys, which in some cases may be an overly conservative option. Careful evaluation of the operating conditions may reveal that expensive alloys may be replaced by cheaper ones in parts of the system. In this paper the corrosion behavior of candidate materials, relevant for use in atmospheric and pressurized alkaline water electrolysis systems, is evaluated at typical operating conditions (i.e. 1-30 bar pressure, 60‑80 °C and 25 wt% KOH). The materials tested are one austenitic stainless steel (UNS S31603), one super duplex stainless steel (UNS S327X0) and one carbon steel (UNS K03014), with one nickel base alloy (UNS N06625) included in the matrix as a reference material. Performance is evaluated based on mass loss corrosion and localized corrosion based on surface profilometry. Corrosion scales and their protectiveness are evaluated based on analysis using SEM/EDS and XRD. Carbon steel was found to have lower corrosion rates than the other steels at all temperatures. Paper reproduced with permission from CORROSION/2019 Annual Conference and Exhibition. www.nace.orgpublishedVersio
Passivation Mechanisms of Atomic Layer-deposited AlOx Films and AlOx/SiOx Stack
Get PDFA new passivation layer of AlOx/SiOx were prepared, in which 80 nm SiOx was prepared by spin-coating perhydropolysilazane (PHPS) and annealed at 450°C. In order to compare the passivation effect of single AlOx layers and the SiOx/AlOx stack on silicon surface, the fixed charge (Qf) in the passivated layers and chemical passivation effect were obtained by corona charge method. Fourier transform infrared spectroscopy (FTIR) and Time-of-flight secondary ion mass spectrometry (TOF-SIMS) was used to investigate the Si-H, Si-O bonds and the hydrogen profile in the passivation layer, respectively. The result reveals that the single layer of AlOx provides good field effect with a large amount of negative Qf. Furthermore, SiOx capping on AlOx have more excellent chemical passivation because of amount of H saturate the dangling bonds on the silicon surface.publishedVersio
Changes in Thermal Stability of Cyclic Aged Commercial Lithium-Ion Cells
Get PDFThermal stability is one of several factors affecting the safety properties of lithium-ion cells. The thermal stability for uncycled cells is well-documented, but the effect of cyclic ageing on thermal stability is far less studied and only for 18650 sized cells. In this paper, we describe how different temperature and current loads are affecting the thermal stability during cyclic aging. Three cylindrical lithium-ion power cells with different cathode, energy content and size were cyclic aged. Decrease in thermal stability was found in all three cyclic ageing test series as a function of relatively high current and low temperature. The decrease in thermal stability could be dangerous and should be an end of life criterion.acceptedVersio
Impact of foundation modelling in offshore wind turbines: Comparison between simulations and field data
Get PDFThe design of Offshore Wind Turbines (OWTs) relies on integrated simulation tools capable of predicting the system dynamic characteristics and the coupled loads and responses. Despite allefforts to develop accurate integrated models, these often fail to reproduce the measured naturalfrequencies, partly due to the modelling of the foundation. Several foundation models and ca-libration approaches have been proposed and compared with small or large scale field tests,where only the soil and the foundation are included. However, there is a lack of more integralvalidation where the interaction between the foundation and the structure is taken into account.The paper investigates the impact of the foundation model and calibration approach on the si-mulated response of a monopile-based OWT installed in the North Sea by comparing simulationsand full-scale field data. The OWT structure and the environmental actions are implemented inthe aero-servo-hydro-elastic code 3DFloat. Two foundation models and two calibration ap-proaches are evaluated. The results indicate that, with a conceptually correct foundation modeland a realistic calibration, it is possible to match the measured natural frequency and predictaccurate fatigue loads. More accurate predicted loads will reduce uncertainties in the estimatedfatigue lifetime and therefore reduce risk in the designImpact of foundation modelling in offshore wind turbines: Comparison between simulations and field dataacceptedVersio
