High-performance and low-cost macroporous calcium oxide based materials for thermochemical energy storage in concentrated solar power plants

High energy density, cycling stability, low cost and scalability are the main features required for thermochemical energy storage systems to achieve a feasible integration in Concentrating Solar Power plants (CSP). While no system has been found to fully satisfy all these requirements, the reversible CaO/CaCO3 carbonation reaction (CaL) is one of the most promising since CaO…

Effects of the speed ratio on the efficiency of planetary mills

The ignition time (tig) of the mechanically induced self-sustaining reaction (MSR) process involving the formation of TiB2 from Ti/2B elemental mixtures was used to study the influence of the ratio (k = -ωv/ωd) between the rotational speed of the supporting disc (ωd) and vials (ωv) on the milling efficiency of a Pulverisette 4 planetary mill. The variation of the inverse…

Electrical properties of bismuth ferrites: Bi2Fe4O9 and Bi25FeO39

Bi2Fe4O9 was prepared by solid-state reaction and the electrical properties measured by impedance spectroscopy. After annealing in O-2 at 900 degrees C, Bi2Fe4O9 is an electrically-homogeneous insulator. Its high frequency permittivity is constant (similar to 14.1) over the temperature range 300-400 degrees C and shows no evidence of incipient ferroelectricity at lower temperatures. On annealing…

Procesado y Caracterización de Composites Cerámicos con Nanomateriales Laminados Bidimensionales

La incorporación de nanomateriales bidimensionales en materiales compuestos de matriz cerámica está aumentando en un esfuerzo para superar la inherente fragilidad de las cerámicas y para conferirles nuevas funcionalidades. Aún existen cuestiones abiertas en este campo en cuanto a resistencia mecánica, tenacidad a la fractura, cinética de crecimiento de fisuras, comportamiento tribológico, papel de fases…

La0.59Li0.24TiO3 ceramics obtained by spark plasma sintering: Electric behavior analysis

This work describes the electric study of Lithium lanthanum titanate (La0.59Li0.24TiO3) ceramics performed by Complex Impedance Spectroscopy. The nanoparticle powders have been synthesized through high energy ball milling and sintered via Spark Plasma Sintering technique. The experimental impedance data have been analyzed using the equivalent circuit model, the Extended Jonscher universal law and the derivative…

Role of calcium looping conditions on the performance of natural and synthetic Ca-based materials for energy storage

In this work, the multicycle activity of natural CaO precursors (limestone and dolomite) and Ca-based composites (Ca3Al2O6/CaCO3 and ZrO2/CaCO3 mixtures) has been studied for Thermochemical Energy Storage (TCES) in Concentrated Solar Power (CSP) plants by means of the Calcium-Looping process (CaL), using two integration schemes proposed elsewhere that differ in the calcination stages. Under CSP-He…

Molten carbonate salts for advanced solar thermal energy power plants: Cover gas effect on fluid thermal stability

The eutectic mixture Li2CO3-Na2CO3-K2CO3 is investigated as a high temperature heat transfer fluid and storage medium alternative for molten salt solar thermal power plants. This salt has an operating temperature range of 400–700 °C, enabling the use of higher temperature/efficiency power cycles. However, this carbonate mixture is known to thermally decompose in air. This study evaluates the thermal stability of the salt mixture under different cover gases:…

Mechanically induced combustion synthesis of niobium carbonitride nanoparticles

Niobium carbonitride [Nb(C,N)] nanoparticles were synthesized by a combustive mechanochemical reaction in the Mg/Nb2O5/C3H6N6 system. High-energy ball milling was used to promote a mechanically induced self-sustaining reaction (MSR). Combustion occurred after a very short milling period of 5 min. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDS) and electron energy loss spectroscopy…