Design and development of a thermochemical energy storage system based on the redox couple Mn2O3/Mn3O4 for concentrated solar power plants

177 p.The future energy grid based on renewable energy sources will require strong support from energy storage systems since renewable energy cannot be managed. Concentrated solar power is one of the leading technologies to produce electrical energy from the sunlight and thermal energy storage systems helps this technology to keep producing electricity in a cloudy day or after sunset. In order to increase the penetration of this technologies, decreasing the cost of concentrated solar power plants becomes of paramount importance to compete with fossil fuel-based energy sources. Advanced thermal energy storage technologies can play an important role in this challenge. Current commercial thermal energy storage systems store the energy using sensible heat with an energy storage density that can be multiplied by 10 if a thermochemical energy storage technology is properly developed. Thermochemical energy storage uses endothermic/exothermic reversible chemical reactions to store and release heat and in addition to their high energy density, they would allow increasing the operation temperatures of the plant and consequently, its efficiency, improving significantly the competitiveness of the technology. Nevertheless, they are still at an early stage of development, requiring mainly to avoid material degradation during cycling, proper design of high temperature components and design an optimal integration into the operation of the plant. Among high temperature thermochemical candidate materials, metal oxides can use air both as heat transfer fluid and reactant, avoiding the use of intermediate heat exchangers or the complexity derived of using other gases such as steam or CO2 required for other type of thermochemical materials. These advantages facilitate their integration into the concentrated solar power plants and therefore, they are one of the most studied thermochemical materials. Within this challenge, we have studied a new approach, for the first time to the best of our knowledge, based on Mn2O3/Mn3O4 thermochemical material. This material has been selected since it is nontoxic and rather available. The objective is mainly focused on improving the thermochemical material behavior during repetitive charge and discharge cycles, as it has been identified as the main drawback of the technology at material scale. The novelty consisted in finding a doping agent that properly mixed with the active material, creates a protective layer around the particles that prevent them from agglomeration and at the same time, contributes to improve the chemical reaction kinetics. Furthermore, a granulation technique has been developed to produce granules of several mm, with enough chemical and mechanical stability, which have been tested and validated in a packed bed configuration within a lab-scale thermochemical reactor

Frictional Heating of Fault Surfaces Due to Seismic Slip: Experimental Studies on the Hematite to Magnetite Transition and Federal and Private Landownership\u27s Effect on Oil and Gas Drilling and Production in the Southwestern Wyoming Checkerboard

This report is a two-part presentation of research within in the fields of rock mechanics and natural resource economics. The first chapter addresses the use of iron oxide oxidation state and thus mineral transitions as a method for determining the frictional temperature rise achieved during an earthquake. Experimental literature on the hematite to magnetite transition is reviewed. Magnetite from transformed or reacted hematite forms between 300-1240 °C. Design and experimental results for a rotary shear apparatus in which hematite is deformed are reported. The measured coefficient of friction for synthetic hematite gouge is 0.38 ±0.03. The second chapter is an investigation of oil and gas production outcomes between federal and private land using a randomized treatment of land ownership. The data comprises oil and gas well drilling and production records located in the railroad land checkerboard, southwestern Wyoming. Spatial and graphical analysis of production and drilling records reveal that federal mineral leases are developed systemically later than private land

Oxygen transport membranes in a biomass/coal combined strategy for reducing CO2 emissions: Permeation study of selected membranes under different CO2-rich atmospheres

[EN] This contribution introduces how the integration of biomass as fuel in power plants would balance CO2 emissions and the related role of oxygen transport membranes (OTM) on it. CO2 capture techniques could be introduced to minimize CO2 emissions at the cost of a substantial energy penalty in the overall process. Among the different approaches, the use of pure O2 and/or N2-free oxidation gases for combustion and/or for gasification leads to promising energy efficiencies. Ceramic OTM membranes could be successfully integrated in such thermal processes, which enable to increase the net plant efficiency when CO2 capture is implemented. Further, this work reviews how selected ceramic materials and membrane architectures behave under CO2 containing atmospheres at high temperatures above 700 °C. These conditions have been selected for checking the viability of these membrane compositions and configurations to fit in an oxy-co-gasification process, involving coal and biomass. The tested asymmetric membranes present competitive oxygen fluxes in the range 0.6 1.2 ml min−1 cm−2 when using CO2 as (inlet) sweep gas at 850 °C (optimal membrane operation conditions in oxy-fuel power plant) and stable oxygen production up to 100 h of continuous operation in similar conditions. Specifically, La0.6Sr0.4Co0.2Fe0.8O3−ä and NiFe2O4 Ce0.8Tb0.2O2−ä composite materials showed the best results for oxygen permeation and time stability under CO2-rich atmospheres.Financial support by the Spanish Government (ENE2011-24761 and SEV-2012-0267 grants), by the EU through FP7 GREEN-CC Project (GA 608524), and by the Helmholtz Association of German Research Centers through the Helmholtz Portfolio MEM-BRAIN is gratefully acknowledged.García Fayos, J.; Vert Belenguer, VB.; Balaguer Ramírez, M.; Solis Díaz, C.; Gaudillere, CC.; Serra Alfaro, JM. (2015). Oxygen transport membranes in a biomass/coal combined strategy for reducing CO2 emissions: Permeation study of selected membranes under different CO2-rich atmospheres. Catalysis Today. 257(2):221-228. https://doi.org/10.1016/j.cattod.2015.04.019S221228257

Characteristics reproducibility of (Fe, Co)(Cr, Al)2O4 pigments obtained by solution combustion synthesis

Synthesis reproducibility of mixed spinels Fe1−ΨCoΨCr2−2ΨAl2ΨO4 (0≤Ψ≤1), obtained by Solution Combustion Synthesis using urea as fuel, has been studied. Pigments with spinel structure Fd-3m have been obtained for all the compositional range analysed. Characteristics such as crystallinity, cell parameter, crystal size and specific surface area show a noticeable dependence with Ψ, but some of them present a low reproducibility, indicating a pronounced dependency with process conditions in each batch. Colouring power of synthesized pigments is highly significant, so they can be directly integrated in ceramic glasses without introducing a second thermal treatment. However, the generated colour also suffers from a limited reproducibilityThe authors thank Universitat Jaume I for their support in the development of this research (Project Nr. P11B2015-04)

Ammonia combustion in furnaces: A review

Ammonia is a formidable chemical that has been investigated over 150 years for its use in the chemical processing field. The potential of the molecule to be used in farming applications has enabled a demographic explosion whilst its implementation in refrigeration technologies ensure continuous operation of cooling systems at high efficiencies. Other areas have also benefited from ammonia, whilst the use of the molecule in fuelling applications was scarce until the 2010s. A combination of factors that include climate change and energy dependency have reignited the interest of using ammonia as an energy vector that can potentially support applications that range from small devices to large power applications, thus supporting the transition to a net zero economy. Therefore, ammonia appears as a tangible option towards the reduction of emissions that can support a truly carbon-free energy transition in the coming years. As the recognition of the molecule increases, research areas based on combustion processes have also expanded towards the utilization of ammonia. The research around the topic has considerably augmented not only in the academic community, but also across governmental institutions and industrial consortia willing to demonstrate the potential of such a chemical. Therefore, this review approaches the latest findings and state-of-the-art research on the use of ammonia as a combustion fuel for furnaces. Different to other reviews, the present work attempts to gather the latest fundamental research, the most critical technologies evaluating ammonia for system operation, and novel approaches that suggest various breakthrough concepts that will ensure the reliable, cleaner consumption of the molecule as furnace fuel. Further, the present manuscript includes the latest research from all corners of the world, in an attempt to summarise the extensive work that dozens of groups are currently conducting. Finally, future trends and requirements are also addressed, providing guidance to those interested in doing research and development in ammonia-fuelling systems

Direct Iron Ore Reduction for Asia

THE increasing shortage of high grade basic materials for, and the high investment cost of, the conventional blast furnace are responsible for the trend in iron ore reducti on technology towards direct processes. In Western Europe the low or short shaft furnace has attracted a considerable amount of development effort while very little research work was devoted there to the fluidised bed technique.On the other hand, the American situation is characterised by a multitude of fluidised bed processes to the virtual exclusion of shaft furnace techniques. Apart front these main trends of development, numerous other processes and promising ideas are tested in pilot or laboratory plants and some have attained almost the stage of commercial utilisation. The technical situation is thus characterised by a great variety and uncertainty. Long range planning is thereby rendered exceedingly complex especially under the pressure of econcmic conditions which enforce, as is the case in Asia, the strictest economy of investment and operation and should be based on a realistic assessment, as is att-emped here, of processes which are well proved in comm-ercial application for a considerable time. Along with these principal processes which are apprai- sed technically and economically and which should command first consideration by planning authorities, significant associated processes are mentioned in acco-rdance with their technical features.Active development projects conclude the listing