Fabrication of Heat Storage Pellets Consisting of a Metallic Latent Heat Storage Microcapsule and an Al₂O₃ Matrix

Abstract

Energy efficiency is fundamental in the steel industry. Latent heat storage (LHS) systems with phase change materials (PCM) are attractive technologies for the recovery and utilization of heat, especially for the development of high-temperature thermal energy storage system. This paper describes fabrication of LHS pellets for high-temperature applications using metallic microencapsulated PCM (MEPCM). The LHS pellets consist of Al-Si PCM parts and an Al 2 O 3 matrix. The pellets were fabricated by mixing MEPCM with sinterable alumina. The powder mixture was then pelletized and sintered at different pressures and atmospheric conditions, respectively. Some MEPCM in the pellets remained spherical after being sintered at 1 000°C, a high-temperature condition above the PCM melting temperature. All fabricated pellets exhibited latent heat of PCM at the melting point of the PCM, about 577°C. The maximum value of latent heat was 73.5 J g − 1. This was observed for the LHS pellet pelletized at 20 MPa and sintered under O 2 atmosphere. Therefore, this study presents a great material for high-temperature thermal energy storage systems in the steel industry. KEY WORDS: steelmaking; high temperature waste heat recovery; phase change material.

Latent heat storage composites composed of Al‐Si microencapsulated phase change material and alumina matrix

“…Al‐25 mass% Si MEPCM (apparent density: 2.89 gcm −3 , average diameter: 42.6 μm, latent heat: 192.56 Jg −1 , melting point of Al‐25 mass% Si: 576°C) was used as the raw material for the composite PCM, along with α‐Al 2 O 3 powder (manufacturer: TAIMEI CHEMICALS Co., Ltd., Model number: TM‐DA, apparent density: 3.95 gcm −3 , average diameter: 0.28 μm, purity: 99.99%) as a sintering aid. The particle size of α‐Al 2 O 3 used in the previous report was micron order, while the smaller sub‐micron order particles were chosen in this report 32 . Smaller particles are expected to sinter in a shorter time and at lower temperatures because of their larger surface area and surface free energy of the driving force for sintering 34,35 .…”

Developing Composite Phase Change Material with Al–Si Base Microencapsulated Phase Change Material and Glass Frit for High Temperature Applications

“…Sakai et al prepared composite PCM with pellet structures by sintering a mixture of Al-25 mass% Si (melting point: 577°C) MEPCM and alumina or glass frit as a sintering aid. 28,29) The composite PCM had a latent heat capacity of 122 J g −1 . 28) However, scope for improvement in the performance of composite PCMs by further optimizing the fabrication conditions still exists.…”

Oxygen Separation Performance of Ca₂AlMnO_5+<i>δ</i> as an Oxygen Storage Material for High-Temperature Pressure Swing Adsorption

“…Microencapsulatedphase-change materials (MEPCMs) that utilize the latent heat of metal are one of the most promising heat-storage materials for use in packed beds. [27][28][29] MEPCMs can maintain a constant temperature based on a latent-heat storage mechanism. In addition, as it can be used on a microscale, the heat-diffusion distance is short and the performance does not depend on the size of the packed bed.…”