Ceria-based materials for high-temperature electrochemistry applications

This paper describes the experimental studies of multi-component solid state electrolytes based on CeO2 and their application in intermediate temperature electrochemical devices. Two important aspects are emphasized: the effect of different dopants’ ionic radius and concentration on the electrical properties of CeO2-based solid solutions in air and the influence of combined dopants on the electrolytic properties of solid electrolytes from the standpoint of the critical oxygen partial pressure pO2 at which point the values of the electronic and ionic components of conductivity are equal. Examples of usage of the developed multi-component Ce0.8(Sm0.75Sr0.2Ba0.05)0.2O2-δ electrolyte synthesized by solid state, laser evaporation and combustion methods and composites on the base of Ce0.8(Sm0.8Sr0.2)0.2O2−d electrolyte as a component of electrochemical devices such as solid oxide fuel cell, gas sensors and as a component of the mixed ionic and electronic conducting (MIEC) membranes for hydrogen and syngas gas production are cited.The present work was financially supported by Russian Foundation for Basic Research and Government of Sverdlovsk region, grant no. 13-03-96098

Comparative study of electrophoretic deposition of doped BaCeO3-based films on La2NiO4+δ and La1.7Ba0.3NiO4+δ cathode substrates

This paper presents the results of a comparative study of methods to prevent the loss of barium during the formation of thin-film proton-conducting electrolyte BaCe0.89Gd0.1Cu0.01O3-δ (BCGCuO) on La2NiO4+δ-based (LNO) cathode substrates by electrophoretic deposition (EPD). Three different methods of the BCGCuO film coating were considered: the formation of the BCGCuO electrolyte film without (1) and with a protective BaCeO3 (BCO) film (2) on the LNO electrode substrate and the formation of the BCGCuO electrolyte film on a modified La1.7Ba0.3NiO4+δ (LBNO) cathode substrate (3). After the cyclic EPD in six stages, the resulting BCGCuO film (6 μm) (1) on the LNO substrate was completely dense, but the scanning electron microscope (SEM) analysis revealed the absence of barium in the film caused by its intensive diffusion into the substrate and evaporation during the sintering. The BCO layer prevented the barium loss in the BCGCuO film (2); however, the protective film possessed a porous island structure, which resulted in the deterioration of the film's conductivity. The use of the modified LBNO cathode also effectively prevented the loss of barium in the BCGCuO film (3). A BCGCuO film whose conductivity behavior most closely resembled that of the compacts was obtained by using this method which has strong potential for practical applications in solid oxide fuel cell (SOFC) technology. © 2019 by the authors.Government Council on Grants, Russian FederationFunding: This research was funded by the Government of the Russian Federation (Agreement 02.A03.21.0006, Act 211)

The use of horizontal wells in inhomogeneous carbonate reservoirs (Cherepetsky horizon of the south-east of the Tatarstan Republic)

Due to the deterioration of the development of oil deposits in clastic reservoirs, last time actively are introduced to the development of carbonate reservoirs with heavy and viscosity oil. Such reservoirs are often characterized by a strong heterogeneity of porosity and permeability and lithological types of rocks. Effective development of oil reservoirs in carbonate reservoir rocks needs in application of new technologies of complex stimulation to reservoirs with using of horizontal wells. It is necessary to study the reaction of the reservoir for additional stimulation and targeted actions of acid solutions. It must be defined sequence of operations in acidizing of low productivity reservoir rocks. Acid solutions are cheap but ineffective. Acids impact to the heterogeneous reservoirs with using the horizontal wells more effective. In the development of deposits in carbonate reservoirs essential help is given by purposeful conducting of horizontal and multilateral wellbores

The development of electrolytes for intermediate temperature solid oxide fuel cells

This report describes a number of experimental studies on the solid state electrolytes for intermediate temperature solid oxide fuel cells (IT-SOFCs): Ce1-xLnxO2-δ (Ln = La, Nd, Sm, Eu, Gd, Dy, Ho, Er, Yb), some multicomponent systems Ce1-xLnx/2Ln x/2O2-δ (x = 0 - 0.20; Ln = Sm, La, Gd and L'n = Dy, Nd, Y), some systems with simultaneous doping by rare earth and alkali earth elements Ce0.8(Sm1-xMx)0.2O2-δ (M = Ca, Sr; x = 0.0 - 1.0) and Ce0.8(Sm1-x-yBayMx)0.2O2-δ (M = Ca, Sr; x = 0, 0.15, 0.20; y = 0.05, 0.1). Two important aspects are emphasized: the effect of different dopants' ionic radius and concentration on the electrical properties of CeO2 based solid solutions and the influence of the method of preparation on the structural properties of ceria ceramics and the electrochemical performance of single SOFCs on their base. To describe the electrolytic properties of solid electrolytes the notation of the electrolytic domain boundary (EDB) - the critical oxygen partial pressure P*O2 at which the values of the electronic and ionic components of conductivity are equal, were calculated and presented. The interpretation of these data will lead to a better understanding of, subsequent improvements to and ultimately, the commercialization of IT-SOFCs in Russia. © 2014 WIT Press.International Journal of Safety and Security Engineering;International Journal of Sustainable Development and Planning;WIT Transactions on Ecology and the Environmen

Diagenetic dolomite reservoirs in carboniferous rocks of Melekess depression and South-Tatar arch

It was studied secondary dolomite reservoirs in Carboniferous oil saturated carbonate rocks from the Melekess depression and South-Tatar arch. It was revealed three morphological types of non-anticlinal dolomite traps: lenticular, one-layer, multilayer. It was found that the development of lenticular dolomite traps confined to zones of oilwater contacts, one-layer to flanks of anticlinal uplifts which connected with the migration ways of oil-water fluids (tectonic faults, erosion incisions). It was suggested the mechanism of formation dolomite reservoir due to the oxidation of hydrocarbons and upward migration of carbon dioxide deep fluids

The Influence of the Substituting Element (M = Ca, Sr, Ba) in La1.7M0.3NiO4+Оґ on the Electrochemical Performance of the Composite Electrodes

The actual work focuses on the development of electrochemically active and stable electrodes for a high temperature proton-conducting electrolyte with a perspective of application in intermediate temperature electrochemical devices. The comparative study of the electrochemical performance of the La1.7M0.3NiO4+δ – based (M = Ca, Sr,Ba) composite cathodes with proton-conducting BaCe0.89Gd0.1Cu0.01O3 or oxygen-ionconducting Ce0.8Sm0.2O1.9 ceramic components in contact with the proton-conducting electrolyte BaCe0.89Gd0.1Cu0.01O3 was performed by an impedance spectroscopy in wet air during 1500 h. The composites were used as functional layers in bi-layered electrodes with current collector layers made of 98 wt.% LаNi0.6Fe0.4O3 + 2 wt.%CuO or 99.4 wt.% La0.6Sr0.4MnO3 + 0.6 wt.% CuO

Structure of oil-water contact zones of Bashkirian carbonate reservoirs

The authors have shown principle structure of oil-water contact zones in Bashkirian carbonate reservoirs of Volga-Ural region. There were established structural and mineral characteristics of oil-water contact zones and were shown main regularities of changing composition of hydrocarbons along the section. It depends from type, speed and intensity of metasomatic transformations of rocks

Peculiarities of structure and formation of oil reservoirs in carbonate rocks of Tournaisian stage of the Republic of Tatarstan

As a result of comprehensive research of limestone Tournaisian stage, the authors identified two major structural and genetic types of carbonate rocks with different petrophysical properties. The most productive limestone is packstone from Kizelovsky horizon. They have high porosity and permeability. Wackestone of Cherepetsky horizon are low-productivity reservoirs. Analysis of carbonate rocks Tournaisian stage showed that the major geological factors, that determined the anisotropy of petrophysical properties of limestone, are the conditions of sedimentation and fluid dynamics of the sedimentary basin. The results of research voids of limestones can reasonably choose the scheme of exploration oil reservoirs of the Tournaisian stage

Typical sections of Bashkirian carbonate rocks and structure of oil deposits in southeast part of the Republic of Tatarstan

Carbonate rocks of Bashkirian stage are regional oil saturation in southeast part of the Republic of Tatarstan. Bashkirian reservoir rocks are not all oil saturation that is caused by environments of carbonate sedimentation. We suggest sedimentation scheme and typical lithological sections of Bashkirian layers. Lithological typification and reconstruction of sedimentation carbonate rocks allows to prospecting oil reservoir. Reservoir type of limestone irregularly detect in Bashkirian sequences. They can form massive and multilayer oil reservoir. Often, section absent reservoir limestone, so this section non perspective for oil development

Diagenesis of the palaeo-oil-water transition zone in a Lower Pennsylvanian carbonate reservoir: Constraints from cathodoluminescence microscopy, microthermometry, and isotope geochemistry

© 2016. Oil-water transition zones in carbonate reservoirs represent important but rarely studied diagenetic environments that are now increasingly re-evaluated because of their potentially large effects on reservoir economics. Here, data from cathodoluminescence and fluorescence microscopy, isotope geochemistry, microthermometry, and X-ray tomography are combined to decipher the diagenetic history of a 5-m-long core interval comprising the oil-water transition zone in a Lower Pennsylvanian carbonate reservoir. The aim is to document the cementation dynamics prior, during, and after oil emplacement in its context of changing fluid parameters. Intergrain porosity mean values of 7% are present in the upper two sub-zones of the oil-water transitions zone but values sharply increase to a mean of 14% in the lower sub-zone grading into the water-saturated portions of the reservoir and a very similar pattern is observed for permeability values. In the top of the water-filled zone, cavernous porosity with mean values of about 24% is found. Carbonate cements formed from the earliest marine to the late burial stage. Five calcite (Ca-1 through 5) and one dolomite (Dol) phase are recognized with phase Ca-4b recording the onset of hydrocarbon migration. Carbon and oxygen cross-plots clearly delineate different paragenetic phases with Ca-4 representing the most depleted δ13C ratios with mean values of about -21‰. During the main phase of oil emplacement, arguably triggered by far-field Alpine tectonics, carbonate cementation was slowed down and eventually ceased in the presence of hydrocarbons and corrosive fluids with temperatures of 110-140 °C and a micro-hiatal surface formed in the paragenetic sequence. These observations support the "oil-inhibits-diagenesis" model. The presence an earlier corrosion surface between phase Ca-3 and 4 is best assigned to initial pulses of ascending corrosive fluids in advance of hydrocarbons. The short-lived nature of the oil migration event found here is rather uncommon when compared to other carbonate reservoirs. The study is relevant as it clearly documents the strengths of a combined petrographic and geochemical study in order to document the timing of oil migration in carbonate reservoirs and its related cementation dynamics