Дисертації з теми "Solid oxide electrolysis cell (SOEC)"
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1
Nelson, George Joseph. "Solid Oxide Cell Constriction Resistance Effects." Thesis, Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/10563.
Повний текст джерелаАнотація:
Solid oxide cells are best known in the energy sector as novel power generation devices through solid oxide fuel cells (SOFCs), which enable the direct conversion of chemical energy to electrical energy and result in high efficiency power generation. However, solid oxide electrolysis cells (SOECs) are receiving increased attention as a hydrogen production technology through high temperature electrolysis applications. The development of higher fidelity methods for modeling transport phenomena within solid oxide cells is necessary for the advancement of these key technologies. The proposed thesis analyzes the increased transport path lengths caused by constriction resistance effects in prevalent solid oxide cell designs. Such effects are so named because they arise from reductions in active transport area.
Constriction resistance effects of SOFC geometry on continuum level mass and electronic transport through SOFC anodes are simulated. These effects are explored via analytic solutions of the Laplace equation with model verification achieved by computational methods such as finite element analysis (FEA). Parametric studies of cell geometry and fuel stream composition are performed based upon the models developed. These studies reveal a competition of losses present between mass and electronic transport losses and demonstrate the benefits of smaller SOFC unit cell geometry. Furthermore, the models developed for SOFC transport phenomena are applied toward the analysis of SOECs. The resulting parametric studies demonstrate that geometric configurations that demonstrate enhanced performance within SOFC operation also demonstrate enhanced performance within SOEC operation.
Secondarily, the electrochemical degradation of SOFCs is explored with respect to delamination cracking phenomena about and within the critical electrolyte-anode interface. For thin electrolytes, constriction resistance effects may lead to the loss of electro-active area at both anode-electrolyte and cathode-electrolyte interfaces. This effect (referred to as masking) results in regions of unutilized electrolyte cross-sectional area, which can be a critical performance hindrance. Again analytic and computational means are employed in analyzing such degradation issues.
2
Milobar, Daniel Gregory. "Analytical Study, One Dimensional Computational Simulation, and Optimization of an Electrode Supported Solid Oxide Electrolysis Cell." Thesis, The University of Arizona, 2010. http://hdl.handle.net/10150/193404.
Повний текст джерелаАнотація:
A one dimensional mass transfer analysis was performed for convective transport as well as mass transport within a porous media. This analysis was based on the analogous average heat transfer within a duct. Equations were developed to calculate the concentration of gas species at the triple phase boundary sites present at the interface of a porous electrode and a nonporous electrolyte. The mass transport analyzed on the steam side electrode of a solid oxide electrolysis cell was performed for a ternary gas mixture. In this analysis two gas species were actively diffusing in the presence of a third inert carrier gas. Multicomponent diffusion coefficients were determined for each species in the steam side electrode mixture. The mass transport analysis performed on the air side electrode utilized a binary gas mixture, namely air. At less than one percent of the total mixture of air, the combined effects of Argon and Carbon Dioxide were assumed to be negligible. This assumption allowed us to consider air a binary mixture. A comprehensive model was developed to determine cell performance under various operating condition and multiple cell geometries. The output of this model was used to optimize various physical features of the cell. Tests were performed on electrode supported solid oxide electrolysis cells at the Idaho National Laboratory. These cells were subjected to various operating temperatures and inlet steam mole fractions. Voltage vs. current density experimental data were collected and compared to computational data in order to validate the model.
3
JAVED, HASSAN. "Design, synthesis and characterization of glass-ceramic and ceramic based materials for solid oxide electrolysis cell (SOEC) applications." Doctoral thesis, Politecnico di Torino, 2019. http://hdl.handle.net/11583/2743336.
Повний текст джерела
4
Mewafy, Basma. "Etude de surface d'électrodes Ni-cermet dans des conditions d'électrolyse à vapeur à température intermédiaire." Thesis, Strasbourg, 2019. http://www.theses.fr/2019STRAF041.
Повний текст джерелаАнотація:
Les cellules d'électrolyse à oxyde solide (SOEC) sont des dispositifs électrochimiques à haute température dans lesquels l'eau se dissocie en hydrogène et en oxygène sous un potentiel appliqué. La technologie SOEC offre un potentiel énorme pour la production future massive d’hydrogène et montre une grande dynamique pour devenir compétitive sur le plan commercial par rapport à d’autres technologies d’électrolyse (par exemple, l’électrolyse à membrane polymère ou alcaline), mieux établies mais plus coûteuses et moins efficaces. Ceci est principalement dû au fait que l'augmentation de la température de fonctionnement permet de réduire considérablement la demande en énergie électrique, ce qui permet des rendements de conversion d'énergie électrique à chimique élevés. À la baisse, les dispositifs des pays de l’Europe centrale et orientale jusqu’à présent ne sont toujours pas viables commercialement, principalement en raison de la difficulté à trouver des matériaux qui répondent aux exigences de haute performance et de durabilité aux températures de fonctionnement élevées. L'objectif général de cette thèse est de traiter les deux inconvénients majeurs qui entravent la pénétration de la technologie SOEC sur le marché de l'énergie, à savoir les taux de dégradation élevés et le coût des équipements. La dégradation de la voltage au cours du vieillissement de la cellule est l’indicateur de performance qui se traduit par une augmentation du overpotential qu’il faut appliquer à une cellule d’électrolyse afin de maintenir une production constante d’hydrogèneSolid Oxide Electrolysis Cells (SOEC) are high temperature electrochemical devices where water dissociates to hydrogen and oxygen under an applied potential. SOEC technology has a huge potential for future mass production of hydrogen and shows great dynamics to become commercially competitive against other electrolysis technologies (e.g. alkaline or polymer membrane electrolysis), which are better established but more expensive and less efficient. This is mainly due to the fact that by increasing the operating temperature the demand in electrical energy is significantly reduced, allowing high electrical-to-chemical energy conversion efficiencies. On the downside, up to now SOECs devices are still not commercially viable mainly due to the difficulty to find materials that fulfill the high-performance and durability requirements at high operating temperatures. The general objective of this thesis is to deal with the two major drawbacks that hamper the penetration of SOEC technology in the energy market, namely high degradation rates and device cost. Voltage degradation during the ageing of the cell is the performance indicator which is translated in an increase on the overpotential that has to be applied to an electrolysis cell in order to maintain constant hydrogen production
5
Tang, Shijie. "Development of Multiphase Oxygen-ion Conducting Electrolytes for Low Temperature Solid Oxide Fuel Cells." Scholarly Repository, 2007. http://scholarlyrepository.miami.edu/oa_theses/112.
Повний текст джерелаАнотація:
One of the major trends of development of solid oxide fuel cells is to reduce the operating temperature from the high temperature range (>950°C) and intermediate temperature range (750-850°C) to the low temperature range (450-650°C). Development of low temperature oxygen ion conducting electrolytes is focused on single-phase materials including Bi2O3 and CeO2-based oxides. These materials have high ion conductivity at the low temperature range, but they are unstable in reducing environments and they are also electronic conductors. In the present research, three types of multiphase materials, Ce0.887Y0.113O1.9435 (CYO)-ZrO2, CYO- yttria-stabilized zirconia (YSZ), and CuO-CYO were investigated. We found that the conductivity of multiphase electrolyte CuO-CYO with a mass ratio of 1:3 is at least 4 times greater than that of CYO and 10 times greater than that of YSZ, the most commonly used material, obtained in the present experiments at 600°C. The enhancement of conductivity in multiphase materials correlates with the level of mismatch between the two phases. Large mismatches in terms of valance and structure result in high vacancy density and hence high oxygen ion conductivity at grain boundaries. This study demonstrates that synthesis of multiphase ceramic materials is a feasible new avenue for development of oxygen ion electrolyte material for low temperature SOFCs.
6
ARAKAKI, ALEXANDER R. "Obtencao de ceramicas de ceria - samaria - gadolinia para aplicacao como eletrolito em celulas a combustivel de oxido solido (SOFC)." reponame:Repositório Institucional do IPEN, 2010. http://repositorio.ipen.br:8080/xmlui/handle/123456789/9506.
Повний текст джерелаАнотація:
Made available in DSpace on 2014-10-09T12:27:27Z (GMT). No. of bitstreams: 0Made available in DSpace on 2014-10-09T14:06:53Z (GMT). No. of bitstreams: 0
Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
7
Anghilante, Régis. "Flexibilisation and integration of solid oxide electrolysis units in power to synthetic natural gas plants." Thesis, Toulouse, INPT, 2020. http://www.theses.fr/2020INPT0094.
Повний текст джерелаАнотація:
La technologie d’électrolyse à oxydes solides (SOE) pourrait permettre d’améliorer l’efficacité des installations de conversion d’électricité en gaz naturel de synthèse (SNG) et de réduire leur coût, grâce à une integration thermique performante, à l’industrialisation de la technologie et une flexibilisation des unités pour la pénétration de l’électricité renouvelable. Une analyse énergétique détaillée de trois concepts d’installations power-to-SNG innovants est d’abord réalisée avec une intégration thermique détailllée. Les installations intégrant des unités SOE et produisant du GNC ou du GNL présentent des rendements d’au moins 78,5% sur base PCS, bien plus élevés que pour les installations intégrant des unités d’électrolyse PEM qui produisent du GNC avec un rendement de 64,4%. La réponse thermique des unités SOE soumises à des variations de charge électrique est ensuite étudiée sur la base d’un modèle dynamique 1D à l’échelle d’une cellule (SOEC). Les cellules « électrolyte support » sont thermiquement plus stables que les « électrode support » et donc plus adaptées à des charges électriques variables. Le modèle est ensuite étendu à une unité entière de production et de stockage d’H2 et couplé à différents profils électriques. L’unité affiche une consommation énergétique de 3,4-3,8 kWh·Nm-3 H2 et un rendement élevé de l’électricité vers l’H2 (93-103%) par récupération de la vapeur de méthanation. Un dimensionnement du réservoir d’H2 et de l’unité de méthanation est réalisé avec un profil électrique éolien. Les charges électriques variables réduisent l’efficacité des installations power-to-SNG, en augmentent les coûts et en complexifient l’opération. Les installations multifuels semblent être l’option la plus prometteuse pour gérer l’intermittence de la production d’électricité. Etendre la gamme d’opération des SOECs aux modes exotherme et endotherme améliorerait les rendements de l’électricité vers l’H2 en comparaison au mode marche/arrêt. Pour une charge électrique constante, les SOECs doivent préférablement être opérées au thermoneutre ou en mode exotherme. Enfin, les coûts de production du SNG sont évalués, en commençant par une estimation ascendante des coûts d’investissement d’unités SOE. Les coûts de production du SNG des concepts étudiés vont de 82 à 89 €·MWh-1 CH4 (PCS) avec des unités SOE, valeurs plus faibles que pour des unités PEM, mais qui restent deux fois supérieures au prix moyen du gaz naturel en FranceThe solid oxide electrolysis technology (SOE) could improve the conversion efficiency of power-tosynthetic natural gas (SNG) plants and reduce their costs, provided that i) a performant thermal integration is implemented ii) the technology is implemented at industrial scale, and iii) plants can absorb the intermittency of renewable power sources. First, the energy analysis of three innovative power-to-SNG plant concepts is implemented. For each concept, a full explicit thermal integration is proposed. Plants with integrated SOE units show efficiencies higher than 78.5% (based on the HHV of the SNG) for the production of CNG and LNG, significantly higher than plants with PEM units with a 64.4% efficiency for CNG production. Second, the thermal response of SOE units to electrical power loads is investigated with a 1D dynamic model at the cell level (SOEC). Electrolyte support cells present a higher thermal stability than electrode support cells and should be preferred for fluctuating power applications. The model was then extended to a full H2 production and storage unit and coupled with different electrical power profiles. The units shows an energy consumption of 3.4-3.8 kWh·Nm-3 H2 and a high power-to-H2 conversion efficiency (93-103%) because of the steam recovery from the methanation unit. A first dimensioning of the H2 storage tank and the methanation unit is proposed, assuming a windmill power profile. Fluctuating power profiles reduce the efficiency of power-to-SNG plants, increase their costs and complexify their operation. Multifuel plants seem to be the most promising option to tackle the issue of intermittent power production. Extending the operation range of SOECs to exothermic and endothermic modes would improve power-to-H2 conversion efficiencies compared to on/off operation. In case of constant power load though, SOECs should preferably be operated at the thermoneutral point or in exothermic mode. Third, SNG production costs corresponding to the aforementioned plant concepts are evaluated, starting with a bottom-up cost evaluation of SOE units. The SNG production costs are in the range of 82-89 €·MWh-1 CH4 (HHV) with SOE units, which is lower than with PEM units, but remains two times higher than the average price of conventional natural gas for all sectors in France
8
Udagawa, Jun. "Hydrogen production through steam electrolysis : model-based evaluation of an intermediate temperature solid oxide electrolysis cell." Thesis, Imperial College London, 2008. http://hdl.handle.net/10044/1/8310.
Повний текст джерелаАнотація:
Steam electrolysis using a solid oxide electrolysis cell at elevated temperatures might offer a solution to high electrical energy consumption associated with conventional water electrolysers through a combination of favourable thermodynamics and kinetics. Although the solid oxide electrolysis cell has not. received significant attention over the past several decades and is yet to be commercialised, there has been an increased interest towards such a technology in recent years, aimed at reducing the cost of electrolytic hydrogen. Here, a one-dimensional dynamic model of a planar cathode-supported intermediate temperature solid oxide electrolysis cell stack has' been developed to investigate the potential for hydrogen production using such an electrolyser. Steady state simulations have indicated that the electrical energy consumption of the modelled stack is significantly lower than those of water electrolysers commercially available today. However, the dependence of stack temperature on the operating point has suggested that there is a need for temperature control. Analysis of a possible temperature control strategy by variation of the air flow rate through the stack has shown that the resulting changes in the convective heat transfer between the air flow and stack can alter the stack temperature. Furthermore, simulated transient responses indicated that manipulation of such an air flow rate can reduce stack temperature excursions during dynamic operation, suggesting that the p,oposed control strategy. has a good potential to prevent issues related to the stack temperature fluctuations.
9
Ricca, Chiara. "Combined theoretical and experimental study of the ionic conduction in oxide-carbonate composite materials as electrolytes for solid oxide fuel cells (SOFC)." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066623/document.
Повний текст джерелаАнотація:
Les composites oxyde-carbonate pourraient constituer des électrolytes pour les SOFC fonctionnant entre 400-600°C car ils attendent une conductivité de 0,1 S/cm à 600°C. Une meilleure compréhension de l'origine de leurs performances est à ce jour nécessaire. Pour y parvenir, une approche combinée théorique et expérimentale a été développée. La conductivité, mesurée à travers la SIE, a été étudiée en fonction de la phase oxyde ou carbonate et de l'atmosphère de travail. Les résultats sur les composite de CeO2 ou YSZ ont montré que seule l'interface peut expliquer des observations surprenantes. De la réactivité a été observée dans le cas des composites à base de TiO2. On a donc proposé une stratégie computationnelle qui utilise des calculs DFT périodiques: la structure du bulk de chaque phase a d'abord été étudiée afin de trouver un bon protocole computationnel, qui a été ensuite utilisé pour identifier un modèle pour la surface la plus stable des deux phases. Ces modèles de surfaces ont donc été combinés pour obtenir un modèle de l'interface oxyde-carbonate, utilisable comme structure de départ pour des calculs DFT et de DM. Cette stratégie a permis d'obtenir des informations sur structure, stabilité et propriétés électroniques des composites. YSZ-LiKCO3 a été utilisé pour mieux comprendre l'effet des interfaces sur le transport de différentes espèces, tandis que le modèle de l'interface entre TiO2 et LiKCO3 a été utilisé pour étudier la réactivité entre ces deux matériaux. Finalement, ces résultats ouvrent la voie vers une plus grande compréhension des principes de fonctionnement des SOFC basées sur les électrolytes composites oxyde-carbonateOxide-carbonate composites are promising electrolytes for LT-SOFC, thanks to their high conductivity (0.1-1 S/cm at 600°C). A deeper understanding on the origins of their improved performances is still necessary. For this purpose, a combined theoretical and experimental approach was developed. We first studied systematically the conductivity of the material, measured through EIS, as a function of different oxide or carbonate phases and of the operating atmosphere. Results on YSZ- and CeO2-based materials indicate that by only taking into account the interfaces it is possible to rationalize some surprising observations, while reactivity issues have been observed for TiO2-carbonate composites. We then proposed a computational strategy based on periodic DFT calculations: we first studied the bulk structure of each phase so as to select an adequate computational protocol, which has then been used to identify a suitable model of the most stable surface for each phase. These surface models have thus been combined to obtain a model of the oxide-carbonate interface that through static DFT and MD provides a deeper insight on the interface at the atomic level. This strategy was applied to provide information on the structure, stability and electronic properties of the interface. YSZ-LiKCO3 was used as a case study to investigate the conduction mechanisms of different species. Results showed a strong influence of the interfaces on the transport properties. The TiO2-LiKCO3 model was, instead, used to investigate the reactivity of these materials. Overall, these results pave the way toward a deeper understanding of the basic operating principles of SOFC based on these materials
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Sharma, Vivek Inder. "Degradation mechanisms in La₀.₈Sr₀.₂CoO₃ as oxygen electrode bond layer in solid oxide electrolytic cells (SOECs)." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/57886.
Повний текст джерелаАнотація:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Nuclear Science and Engineering, 2009.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 100-104).
High temperature steam electrolysis is an efficient process and a promising technology to convert electricity and steam or a mixture of steam and CO₂, into H₂ or syn-gas (H₂2 + CO) respectively. It is carried out in Solid Oxide Electrolytic Cells (SOECs). At the high temperature of operation, above 8000[degree] C, loss in the rate of hydrogen (or syn gas) production by SOECs has been observed. This loss of performance has been a scientific and technological challenge. The goal of this thesis is to identify the mechanisms for the loss in the electrochemical performance of SOECs due to the oxygen electrode and bond layer degradation. Our specific research objectives were focused on two main mechanisms: 1) Cr transport into the oxygen electrode and bond layer, and 2) Long-range segregation of cations in the bond layer. For SOECs provided by Ceramatec Inc. for this analysis, La₀.₈Sr₀.₂CoO₃ (LSC) was the bond layer and A₀.₈Sr₀.₂MnO₃ (ASM*) was the oxygen electrode, both comprised of perovskite structure. The approach in thesis integrated complementary spectroscopy and microscopy techniques in a novel manner to carry out the 'post-mortem' analysis of SOECs from a high level to a high resolution. Raman spectroscopy was employed to identify secondary phases on the top surface of LSC near the interconnect interphase. Surface chemistry and microstructure of the air electrode and the bond layer was studied using scanning Auger Electron Spectroscopy (AES) with nano-probe capability.
(cont.) High-resolution analysis of the cation distribution in the bulk of the LSC bond layer was achieved by employing Energy Dispersive X-ray Analysis (EDX) coupled with Scanning Transmission Electron Microscopy (STEM). Electrochemical treatment and characterization was performed to isolate the mechanism(s) governing the long-range segregation of cations, leading to the dissociation of the LSC bond layer. Less-conducting, secondary phases of Cr₂O₃, LaCrO₃, La₂CrO₆ and Co₃0₄ were identified on the top surface of LSC bond layer. The bond layer exhibited: 1) presence of Cr, with average Cr-fraction of approximately 0.07 at the surface of its grains, and 2) surface composition variation locally, with La/Co ranging widely from 0.67 to 16.37 compared to the stoichiometric La/Co value of 0.8. Sr and Co cations migrated from the bond layer structure to the LSC/interconnect interface, over a distance of 10-20 microns. Furthermore, STEM/EDX results showed the presence of phase separated regions at the nano-scale rich in Cr and La but lacking Co, and vice-versa. This indicates the dissociation of bond layer bulk structure at nano-scale. Cr fraction in LSC bulk varied from 10 to 33%, which is higher than the average Cr-content at the surface of LSC grains. The maximum Sr fraction observed in LSC bulk was 4.16%, confirming the migration of Sr to LSC/interconnect interface.
(cont.) We hypothesize that the long-range transport of Sr, Co, and Cr cations can be caused by two primary mechanisms: 1) Driven by Cr-related thermodynamics, where the Crcontaning species (i.e. at the vicinity of the interconnect) could thermodynamically favor the presence of select cations (i.e. Sr and Co) at the region interfacing the interconnect. 2) Driven by the electronic or oxygen ion current. To test these hypotheses and to isolate the governing mechanism, we simulated controlled electrochemical conditions on reference cells having ASM electrodes coated with LSC, on both sides of SSZ electrolyte, without any Cr-containing layers on the LSC bond layer. The reference cells degraded even in the absence of Cr. AES results showed that the microstructure and surface composition of the reference cells stayed stable and uniform upon the electrochemical treatment, in spite of the degradation. Thus, this thesis concludes that the Cr-related thermodynamics could be the dominant mechanism driving the uneven dissociation and segregation of cations in LSC as observed in the stack cells. As a mechanism for Cr-deposition in the LSC bond layer, we suggest that a thermodynamically-favored reaction between the La-enriched phase (at the surface of the LSC grains) and the volatile Cr-species (Cr0₃ and CrO₂(OH)) is responsible for the formation of poorly-conducting secondary phases. This interaction is likely to be limited by the presence of the segregated La-O-species which can serve as a nucleation agent for this reaction.
by Vivek Inder Sharma.
S.M.
11
Vandana, Singh. "Development of High Performance Electrodes for High Temperature Solid Oxide Electrolysis Cells." 京都大学 (Kyoto University), 2016. http://hdl.handle.net/2433/215556.
Повний текст джерела
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Gambino, Marianna. "Structural study, computational analysis and structure-property correlations in anion conducting electrolytes for Solid Oxide Fuel Cells." Doctoral thesis, Università di Catania, 2017. http://hdl.handle.net/10761/3882.
Повний текст джерелаАнотація:
A combined experimental and theoretical approach has been used in order to investigate the local structural features that have an influence on ionic conductivity of IT-SOFC (Intermediate Temperature Solid Oxide Fuel Cell) electrolytes, in order to link the properties of these materials with their atomic and electronic structure.
Doped delta-Bi2O3 and LaGaO3 electrolytes for AC-SOFC applications have been studied as model compounds for oxygen-ion diffusion in fluorite-like and perovskite-like materials, due to their incredibly high anion conductivity. A combined X-Ray Absorption Spectroscopy (XAS) and Density Functional Theory (DFT) study has been carried out with the aim to unveil the role of the dopants on the short range structure of these materials, to probe the preferential association of vacancies with both dopant and regular site cations, and to highlight the preferential oxygen-ion diffusion paths. This could help to define criteria for the design of new materials with improved properties.
The influence of the electrode-electrolyte interface on the overall fuel cell ionic conductivity has been also addressed. To this aim, a novel protocol to evaluate electrode-electrolyte compatibility through Scanning X-Ray Microscopy (SXM) has been developed and cation interdiffusion has been successfully probed at the interface between some electrolyte-cathode couples.
13
Omojola, Kayode. "High temperature co-electrolysis of carbon dioxide and steam in a solid oxide cell for synthesis gas production." Thesis, University of Sheffield, 2015. http://etheses.whiterose.ac.uk/8497/.
Повний текст джерелаАнотація:
The utilisation of CO2 as a feedstock in the production of valuable products such as synthetic fuel is a promising pathway for mitigating its atmospheric concentration. A review of the high temperature co-electrolysis of CO2 and H2O in a solid oxide cell for syngas production has identified that further understanding of the co-electrolysis reaction mechanism is one of three key areas of development. In this work, a co-electrolysis test facility was designed, developed and commissioned. Additionally, the performance of a NextCellTM electrolyte supported cell was investigated for CO2 electrolysis and CO2/H2O co-electrolysis with an aim to gain a better understanding of the reaction mechanism. During CO2 electrolysis, an increase in cell area specific resistance was observed with increasing CO2 concentration. In addition, AC impedance spectra measurements showed a significant increase in polarisation resistance at the fuel electrode with increasing CO2/CO ratio. Short term durability studies carried out at -0.5 A/cm2, 850oC and fuel electrode compositions of 50% CO2, 25% CO and 25% N2 showed a sharp increase in cell voltage corresponding to a passivation rate of 120 mV/h in the first 5 hours of operation. This increase in cell voltage was caused by the adsorption of impurities to the Ni surface prompting partial blockage of the active Ni sites. During CO2/H2O co-electrolysis, the exhaust gas compositions measured at open circuit voltage were ±2 mol % of the thermodynamic equilibrium compositions. AC impedance spectra measurements showed a slight increase in polarisation resistance at the fuel electrode with increasing CO2/H2O concentration. Direct current measurements showed a 21% increase in cell performance during CO2/H2O co-electrolysis compared to CO2 electrolysis. Furthermore, co-electrolysis durability studies carried out at -0.5 A/cm2 showed a significantly lower degradation rate of 1.3 mV/h over 44 hours of operation compared to CO2 electrolysis.
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Deka, Dhruba Jyoti. "Development of Cathode Catalysts for the Production of Synthesis Gas and Ammonia in Solid Oxide Electrolysis Cells." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1588693027481087.
Повний текст джерела
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Qadri, Syed N. "Development of a double-layered perovskite as alternative anode material for high temperature steam electrolysis." Thesis, University of St Andrews, 2014. http://hdl.handle.net/10023/5826.
Повний текст джерелаАнотація:
The research presented is based on alternative anode materials for high temperature steam electrolysis. The key to commercially viable renewable energy economy is based on energy storage of intermittent sources. Hydrogen is the preferred form of energy storage for solid oxide electrolysis cells. However, conventional anode material lanthanum strontium manganite (LSM), suffers from poor ionic conductivity, thus prohibiting much of the bulk electrode from providing an enhanced electrochemical performance. This study explores the use of a double-layered perovskite system with mixed electronic and ionic conductivity for use as anode material. Specifically, the SmBa₁₋ₓSrₓCo₂O[sub](5+δ) system (SBSCO) is analyzed for characteristics that may enhance the performance and feasibility of SBSCO as an alternative anode material to LSM. Previous in-house work showed SmBa₀.₅Sr₀.₅Co₂O[sub](5+δ) had the lowest area specific resistance of any double- layered material reported. Here the system is further explored by studying the full range of compositions. From X-ray diffraction analysis, increased Sr substitution leads to a tetragonal phase change in SBSCO. High temperature x-ray diffraction of compositions showed thermal stability of structure. Magnetization measurements are reported for selected compositions. The stability of SBSCO was examined in CO₂ containing atmospheres. Despite containing alkaline earth metals, the system offers limited CO₂ tolerance. A set of thermodynamic parameters is presented based on CO₂ partial pressure and temperature. Model indicates SBSCO is a stable electrode material for both electrolysis and fuel cell modes. Compositions were tested for steam electrolysis performance with the use of YSZ electrolyte, and Ni-YSZ and La₀.₄Sr₀.₄Ni₀.₀₆Ti₀.₉₄O₂.₉₄ cathodes. SmBa₀.₃Sr₀.₇Co₂O[sub](5+δ) had the highest performance for compositions (0≤x≤1) based on I-V curves and impedance measurements. Stability tests were conducted in potentiostatic mode and no delamination was observed for SBSCO in microstructural analysis after testing. From these studies, SBSCO is demonstrated to be a suitable for application in electrolysis and an alternative for LSM as anode material.
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Sar, Jaroslaw. "Interfaces et durabilité d'électrodes avancées pour l'énergie : IT-SOFC et SOEC Coral Microstructure of Graded CGO/LSCF Oxygen Electrode by Electrostatic Spray Deposition for Energy (IT-SOFC, SOEC) Electrochemical properties of graded and homogeneous Ce0.9Gd0.1O2-δ-La0.6Sr0.4Co0.2Fe0.8O3-δ composite electrodes for intermediate-temperature solid oxide fuel cells Three dimensional analysis of Ce0.9Gd0.1O1.95–La0.6Sr0.4Co0.2Fe0.8O3−δ oxygen electrode for solid oxide cells Mechanical behavior of Ce0.9Gd0.1O1.95-La0.6Sr0.4Co0.2Fe0.8O3−δ oxygen electrode with a coral microstructure for solid oxide fuel cell and solid oxide electrolyzer cell Durability test on coral Ce0.9Gd0.1O2-δ-La0.6Sr0.4Co0.2Fe0.8O3-δ with La0.6Sr0.4Co0.2Fe0.8O3-δ current collector working in SOFC and SOEC modes". Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENI106.
Повний текст джерелаАнотація:
Interfaces et durabilité des électrodes de pointe pour l'énergie (PAC et EHT)L'objectif de cette thèse concerne l'élaboration, par atomisation électrostatique, d'une électrode à oxygène à architecture innovante, basée sur un composite Ce0.9Gd0.1O1.95 (CGO) - La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) possédant un gradient de composition ou une composition homogène. Cette électrode a été déposée sur un substrat de zircone yttriée (YSZ = 8 % mol. Y2O3-ZrO2) sur laquelle, a été intercalée au préalable une couche barrière mince et dense de CGO. Cette électrode possède une microstructure innovante, à porosité élevée permettant d'obtenir une grande surface active qui devrait conduire à l'amélioration des performances électrochimiques. Le comportement électrique de l'électrode a été étudié par spectroscopie d'impédance en fonction de la température et sous air. Une description microstructurale détaillée a été effectuée à l'aide d'un modèle de reconstruction 3D obtenu par -MEB équipé d'une sonde ionique focalisée et par nanotomographie X. Ces propriétés microstructurales ont été reliées aux propriétés électriques. Les propriétés mécaniques et tribologiques de cette électrode composite ont été déterminées par des tests du scotch et ultra-microindentation. Finalement, des tests de durabilité ont été effectués sur une électrode de grande taille possédant une surface active de 45 cm2 jusqu'à 800 h à environ 770°C, dans une cellule complète de configurations PAC et fonctionnant respectivement sous H2 et un mélange H2/H2OInterfaces and durability of advanced electrodes for energy (IT-SOFC and SOEC)The objective of this PhD thesis is to fabricate advanced oxygen electrode based on Ce0.9Gd0.1O1.95 (CGO) and La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) with graded and homogeneous composition onto yttria-stabilized zirconia (YSZ = 8 mol. % Y2O3-doped ZrO2) electrolyte using electrostatic spray deposition. A thin and dense layer of CGO was inserted between LSCF and YSZ to serve as a barrier diffusion layer. The novel microstructure with high porosity and large surface area is expected to improve the electrochemical performances. The electrical behavior of the electrode was investigated by impedance spectroscopy versus temperature in air. A detailed microstructural description was performed by 3D reconstructed model from FIB-SEM and X-ray nanotomography and related to electrical properties. The mechanical analysis was performed by scratch and ultramicroindentation tests. Finally, durability tests were performed on the electrode with 45 cm2 oxygen active area, up to 800 h at around 770°C, in full cell SOFC and SOEC configurations operating respectively in H2 and H2/ H2O mixture
17
Petipas, Floriane. "Conception et conduite de systèmes d’électrolyse à haute température alimentés par des énergies renouvelables." Thesis, Paris, ENMP, 2013. http://www.theses.fr/2013ENMP0015/document.
Повний текст джерелаАнотація:
Le « Power-to-Gas » pourrait devenir une solution attractive pour le stockage des énergies renouvelables, pourvu que des électrolyseurs soient capables de fonctionner efficacement dans des conditions intermittentes à un coût abordable. Ce travail a pour objectif d'évaluer la faisabilité technique du fonctionnement intermittent de systèmes d'électrolyse à oxyde solide (SOEC) autour de 1073 K. Des conditions réalistes défavorables sont considérées, consistant en un système autonome sans source externe de chaleur et intégrant une compression d'hydrogène à 3 MPa. La problématique se compose de deux aspects : i) la gamme de fonctionnement du système, limitée à 60-100% en raison de gradients thermiques, est étendue via des stratégies de contrôle efficaces, ii) des procédures sont définies pour minimiser l'impact de l'intermittence sur la durée de vie. Premièrement, une stratégie de contrôle modulaire est proposée, consistant en l'utilisation de plusieurs unités indépendantes qui fonctionnent dans une gamme de puissance tolérable, ou sont arrêtées. La gamme de fonctionnement du système est ainsi étendue à 15-100% dans le cas de quatre unités. Une stratégie de contrôle complémentaire, consistant en un chauffage électrique interne, permet d'étendre la gamme de fonctionnement en réduisant les gradients thermiques, mais elle est susceptible de diminuer la durée de vie. Elle n'est donc appliquée qu'à une unité afin de suivre la courbe de charge et d'étendre la gamme de fonctionnement du système à 3-100%. Deuxièmement, 1800 cycles électriques on-off sont appliqués à une SOEC sans impact sur la dégradation, ce qui montre que des arrêts/démarrages répétés ne diminuent pas la durée de vie. De plus, des procédures de démarrage, standby et arrêt sont définies. Enfin, deux études de systèmes Eolien-SOEC et Solaire-SOEC fonctionnant pendant un an montrent que, avec les stratégies de contrôle implémentées, le système SOEC stocke la puissance appliquée avec un rendement de 91% sur PCS en moyenne, alors que les unités fonctionnent dans des conditions tolérables mis à part une unité qui suit la courbe de charge et est susceptible d'avoir une durée de vie diminuéePower-to-Gas could become an attractive solution for renewable electricity storage, provided that affordable electrolysers are able to operate efficiently under intermittent conditions. This work aims to assess the technical feasibility of operating intermittently a Solid Oxide Electrolysis Cell (SOEC) system around 1073 K. Realistic unfavourable conditions are considered, consisting in a standalone system operated with no external heat source and integrating hydrogen compression to 3 MPa. Two challenges are tackled in this work: i) the system power load range, limited to 60-100% due to thermal gradients, is extended via efficient control strategies, ii) procedures are defined to minimise the impact of the intermittency on the lifetime. First, a modular control strategy is proposed, consisting in the use of several SOEC units which are either operated in a tolerable power load range, or switched off. The system power load range is hence extended to 15-100% in the case of four units. A complementary control strategy, consisting in internal electrical heating, enables to extend the load range by reducing thermal gradients, but it may decrease the lifetime. Thus, it is applied to only one unit for it to follow the load curve and extend the system power load range to 3-100%. Secondly, 1800 on-off electric cycles are applied to an SOEC with no degradation increase, which shows that repeated start/stops do not decrease the lifetime. Start-up, standby and shut-down procedures are also defined. Finally, two case studies of Wind-SOEC and Solar-SOEC systems operated over one year show that, with the implemented control strategies, the SOEC system stores the applied power with an average efficiency of 91% vs. HHV, while units operate under tolerable conditions apart from one unit which follows the load curve and may have a decreased lifetime
18
Hsieh, Yu-Pin, and 謝煜彬. "Development of Electrolyte Materials for Solid Oxide Electrolysis Cell." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/27g8dj.
Повний текст джерелаАнотація:
碩士國立中央大學
機械工程學系
105
In this study, we investigate the electrolyte materials for high temperature solid oxide electrolysis cells. The electrolyte is prepared by using yttriumstabilized zirconia (YSZ) as the basis, doped with titanium dioxide (TiO2) and samarium doped cerium oxide (SDC). The microstructure and mechanical properties of the electrolyte are investigated for different pre-sintering temperature, the uniaxial pressure and pressurized duration for producing pellets, and sintering temperature. The cathode and anode are prepared by screen printing. The cathode material is nickel-yttria stabilized zirconia (Ni-YSZ), and the anode material is lanthanum strontium manganese (LSM) perovskite material. The cell performance is measured in power generation mode by supplying hydrogen to Ni–YSZ electrode and oxygen to LSM electrode. The performance in electrolysis mode is measured by supplying carbon dioxide to Ni-YSZ electrode. Results show that YSZ doped TiO2 and SDC can reduce the sintering temperature. Electrolytes with large grains, averaged at 50.4 μm, can be obtained using a pre-sintering temperature of 1250 ºC, a pressure of 294 MPa for 5 minutes for producing pellets, and a sintering temperature of 1550 ºC. In addition, the thermal expansion coefficient at 1000 ºC is 8.25 10-6 /K, the Vickers hardness value is 1183.5 HV. The current density of the cell is 631 mA/cm2 at 1.5V and 1000 ºC in the electrolysis mode.
19
Wu, Chih-Hsuan, and 吳至璿. "Electrochemical performance of Gd-doped ceria interlayer on the solid oxide fuel cell and solid oxide electrolysis cell." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/97721891665094352738.
Повний текст джерелаАнотація:
碩士元智大學
機械工程學系
105
A procedure is mainly study the intermediate temperature solid oxide fuel cell (IT-SOFC), and further develop it into Utilized Regenerative solid oxide fuel cell (URSOFC), which has the capability of SOFC and SOEC bidirectional mode. In this study, an anode supported button cell was prepared by TLC method. The anode material was porous nickel oxide (NiO-YSZ) and lanthanum strontium cobalt ferrite (LSCF) was used as the cathode material. The lanthanum strontium cobalt ferrite is a mixed ionic electronic conductor with respect to the lanthanum strontium manganese (LSM) with higher electrical conductivity and good ionic conductivity. But at high temperatures with the electrolyte YSZ produce non-conductive phase such as: La2Zr2O7、SrZrO3. In order to avoid this phenomenon, we devoted to study of GDC interlayer sintering process, and GDC interlayer sintered between 1200-1300 degrees. And test at 700-850 degrees to know the chemical performance. We used SEM to know the cell microstructure changed after SOFC mode and SOEC mode. Finally, we found that the GDC interlayer sintered at 1300 degrees had a maximum power density of 288.578 (mW/cm2) at operation temperature 850 °C. And one of the biggest increases in performance is the GDC interlayer sintered at 1250 degrees with a maximum current density 648.464 (mA / cm2) at 2.0 V at 850 °C. Compared to traditional SOFC, electrolysis performance will get 386% performance improvement.
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Dlamini, Mangaliso Menzi, and 梅傑. "MODELLING AND EXPERIMENT ANALYSIS FOR REVERSIBLE SOLID OXIDE ELECTROLYSIS CELL POROSITY EFFECT." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/5528s9.
Повний текст джерелаАнотація:
碩士元智大學
機械工程學系
106
This study is focused on modeling and experimental analysis of Solid Oxide Cells (SOCs), which is operated in reversible modes (Fuel cell mode and Electrolysis cell mode). In order to develop low operating temperature boundary condition to accommodate more excellent materials to be used in this innovation, strategies have been instituted. With the electrolysis mode, hydrogen is the main products from the splitting of water components while electricity is the main product under the fuel cell mode. A button cell in steady state condition is used for both modeling and experiment analysis. Porosity and operation temperature (600, 700, 750 and 800 °C) is regarded as the control measure for the analysis as this technology is electrochemical. The anode sintering temperatures (anode: 1300, 1400 and 1500 °C) and heating rate is varied with the cathode sintering temperature (cathode 1200°C) held constant to control the porosity of the cell components (electrodes and electrolyte) for the gas diffusion and ionic/electronic transfer. Experimental results also included the property measurements for porosity to study the cell performance. A summary of the critical values for optimum cell performance under these control measures is derived after this study. COMSOL Multiphysics is used to simulate the experimental procedures and further compare the results. Butler–Volmer equation is implemented to predict the cell current density distribution and Modified Stefan-Maxwell diffusion model incorporating Knudsen diffusion equation for multicomponent diffusion. The modeling part discusses the optimal cell porosity on effective diffusions and conductivity for SOEC mode of hydrogen production and also reversible SOEC mode for renewable energy storage and electricity production. Keywords: Solid Oxide Cells, Electrolysis, Fuel Cell, Reversible Mode, Porosity, Sintering, Temperature, Diffusion, Conductivity.
21
Lin, Sheng-Jun, and 林聖鈞. "Analysis of Wind Power and Solar Power with Solid Oxide Electrolysis Cell hybrid System." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/42265509118114989480.
Повний текст джерелаАнотація:
碩士國立中央大學
能源工程研究所
105
This study demonstrates a hybrid energy system combine with the renewable energy and hydrogen storage systems. The system is powered by wind turbines and solar cell, and a proton conducting solid oxide electrolysis cell (p-SOEC) is used for hydrogen production from excess energy. Five components install in this hybrid system: wind turbines, solar cells, p-SOEC, PEM fuel cells, and hydrogen storage tanks. The system analysis is based on the real conditions from four offshore islands of Taiwan, including of Penghu-Makung, Kinmen, Matsu, and Green Island. Effects of the system from each component are discussed and concluded. This study is analyzed by using MATLAB and Excel. The results show that enlarge the wind power percentage of Penghu-Makung would increase system energy supply. However, when the wind power percentage excess 50 %, incremental of the system energy supply becomes smaller. Solar power is stable in Kinmen and increasing the solar power penetration of Kinmen would enhance the system energy supply. In Matsu, wind power is stronger and more stable. Enlarge the wind power penetration of Matsu would increase the system energy supply. The natural condition of Green Island is similar to Penghu-Makung, but residential electricity of Green Island is smaller than Penghu-Makung. According to the natural conditions and residential electricity demand, it can be found that the hybrid system has advantages at the region with obviously periodical changes on climates. Green Island is suitable for preliminary system evaluation.
22
Costa, Bernardo Filipe Serôdio. "Ni-Sr(V,Ti,Ni)O3 electrodes for reversible solid electrolyte cells." Master's thesis, 2019. http://hdl.handle.net/10773/28144.
Повний текст джерелаАнотація:
The main objective of this work was to assess the possibility of the enhancement of the electrocatalytic activity of Sr(Ti,V)O3-δ fuel electrode components for high-temperature solid electrolyte cells by introducing Ni into the B-sublattice of the perovskite structure with in-situ nanostructuring under operation conditions by exsolution. The work was motivated by the drawbacks of commonly used cermet Ni-YSZ cermet anodes such as long-term microstructural degradation and intolerance to redox changes, sulfur poisoning and carbon deposition. Strontium titanate-vanadates were considered as suitable ceramic components stable under fuel electrode operation conditions and with prospects for sulfur and carbon deposition tolerance, while nano-dispersed Ni was expected to enhance the electrocatalytic activity while avoiding the disadvantages of Ni-YSZ cermets.
High-energy mechanochemical route in combination with thermal treatments under controlled reducing atmosphere were employed for the preparation of selected materials with a nominal composition Sr1-xTi1-y-zVyNizO3 (x = 0-0.04, y = 0.2-0.4, z = 0.02-0.12). Detailed analysis of the phase formation in this system revealed that comparatively high thermal treatment temperature (1200°C), required to eliminate the undesired insulating Sr3(VO4)2 intermediate phase in the course of synthesis of Sr(Ti,V)O3 perovskites, results in a segregation of Ni in the form of poorly dispersed submicron metallic particles.
Prepared Sr1-x(Ti,V)O3-δ-Ni ceramic materials exhibited a moderate thermal expansion coefficients compatible with that of YSZ solid electrolyte. The electrical conductivity was found to increase with increasing vanadium content in the perovskite phase, while the nominal A-site deficiency had an opposite effect. The electrochemical impedance spectroscopy studies revealed a rather poor activity of Sr1-x(Ti,V)O3-δ-Ni porous electrodes for hydrogen oxidation reaction. This was ascribed to insufficient intrinsic electrocatalytic activity of Sr1-x(Ti,V)O3 perovskites, low expected ionic conduction in these phases, and segregation of Ni particles in the course of synthesis. It was demonstrated that the electrochemical performance of these electrodes can be substantially improved by the infiltrations of gadolinia-doped ceria as oxygen-ion conducting component and small extra amounts of well-dispersed Ni as an electrocatalystO principal objetivo deste trabalho foi avaliar a possibilidade de melhoria da atividade eletrocatalítica de elétrodos de combustível Sr(Ti,V)O3-δ utilizados em eletrólitos de alta temperatura, introduzindo Ni na subrede B da estrutura do tipo perovskite, com nanoestruturação in-situ em condições de operação por via de exsolução. Este trabalho teve como motivação as desvantagens associadas ao uso típico de ânodos cermet Ni-YSZ, como degradação da microestrutura a longo termo e intolerância a mudanças redox, contaminação de enxofre e deposição de carbono. Foi considerado o uso de titanato-vanadato de estrôncio como componentes cerâmicos adequados dentro das condições de operação de elétrodos de combustível e com vista a tolerar a deposição de carbono e enxofre, enquanto se perspectivava que Ni nano-dispersado pudesse aumentar a atividade eletrocatalítica, evitando as desvantagens associadas ao cermet Ni-YSZ. Tratamentos mecanoquímicos de alta energia, em combinação com tratamentos térmicos sob atmosferas redutoras foram aplicados na preparação dos materiais selecionados de composição nominal Sr1-xTi1-y-zVyNizO3 (x = 0-0.04, y = 0.2-0.4, z = 0.02-0.12). Análise detalhada à formação de fases no sistema revelou que é necessário um tratamento térmico de relativamente alta temperatura (1200 °C) de modo a eliminar a fase intermédia Sr3(VO4)2, indesejada no curso da síntese de perovskites do tipo Sr(Ti,V)O3, que resulta na segregação do Ni na forma de partículas metálicas abaixo do mícron, deficientemente dispersas. Os cerâmicos Sr1-x(Ti,V)O3-δ-Ni preparados exibiram um coeficiente de expansão térmica moderado, comparativamente ao do eletrólito utilizado YSZ. A condutividade elétrica provou-se aumentar em função da quantidade de vanádio na perovskite, enquanto que deficiência nominal no elemento A provocaria o efeito oposto. Estudos na espectroscopia de impedância eletroquímica revelaram fraca atividade dos elétrodos porosos Sr1-x(Ti,V)O3-δ-Ni em oxidação de hidrogénio. Isto foi atribuído a uma atividade eletrocatalítica intrinsecamente insuficiente, fraca condução iónica destas fases e segregação das partículas de Ni no decorrer da síntese. Ficou demonstrado que a performance eletroquímica destes elétrodos pode ser substancialmente melhorada com a infiltração de soluções contendo Céria dopada com Gadolínia, usada como condutor iónico de oxigénio, assim como soluções da mesma contendo Ni bem disperso de modo a atuar como catalizador
Mestrado em Engenharia de Materiais
23
CHEN, CHIH-WEI, and 陳志瑋. "Design and Performance Evaluation of Tri-Generation Systems for Hydrogen, Heat and Power Production using Solid Oxide Fuel-assisted Electrolysis Cell." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/pm2jwb.
Повний текст джерелаАнотація:
碩士國立臺北科技大學
化學工程與生物科技系化學工程碩士班
107
As a promising technology in the field of hydrogen energy, solid oxide cell (SOC) has high energy conversion efficiency due to its high temperature operating condition. This study proposes a new high-performance tri-generation system based on fuel-assisted solid oxide electrolysis cell (SOFEC) coupled to solid oxide fuel cell (SOFC). In this configuration, SOFC can provide power, heat that the SOFEC required for the electrolysis and steam reforming reaction. In addition to the fuel that can be fed back to the SOFC, the SOFEC can not only operates without electrical energy but can also generate electricity like a SOFC. For the more flexible energy production strategies, it would enable the extension of combined heat and power (CHP) system to combined hydrogen, heat and power (CHHP) system. This research will design several major operational variables for the integrated system, including the operating temperature, number of cells, fuel and electrolysis utilization. The overall performance will be evaluated through system simulation, and the optimal system architecture, operating conditions will be developed. Simulation results indicate that electrical and thermal efficiency of the conventional CHP system are 59.05% and 16.80% at highest fuel utilization. Under the maximum power demand consideration, the CHHP system shows an electrical efficiency of 46.78%, simultaneously, it has a hydrogen production efficiency of 11.58% and a thermal efficiency of 18.69%. One the contrary, under the maximum hydrogen production demand, the CHHP system can obtain a hydrogen production efficiency of up to 57.90%, simultaneously, it has an electrical efficiency of 21.32% and a thermal efficiency of 0.70%.