Development of an Advanced Ceramic, Recycled from Electric Arc Furnace Steel Slags, as Energy Storage Thermocline Filler Materials

  • Kholoud Al Naimi

Student thesis: Doctoral Thesis

Abstract

The deployment of solar energy technologies in the United Arab Emirates has increased over the past five years as part of the country's tremendous efforts to diversify its energy sources and reduce the carbon footprint associated with the consumption of fossil fuels. However, since solar energy is intermittent and continuous power production cannot be granted, especially at peak hours, the need for energy storage has been addressed. Among the different solar technologies, concentrated solar power (CSP) has received interest when the ability of integrating thermal energy storage (TES) systems into the CSP plant was recognized. The TES systems can grant availability and dispatchability of electricity 24/7. For the next generation of high-temperature central receiver CSP plant, a suitable TES system that can withstand high temperatures is required. There are several TES technologies available, with the two-tank molten salts successfully applied on a commercial scale. Nevertheless, due to the limitations of molten salt that prevent using it at temperatures higher than 600 ℃, there is a need for alternative TES concepts and storage materials. Therefore, this research thesis focused on developing a systematic process of advanced ceramic material with optimal thermophysical properties and made out of 100% electric arc furnace (EAF) steel slags. This industrial waste-based (IWB) ceramic is to be used as a shaped homogenous thermal energy storage (TES) media in packed-bed thermocline systems. Sustainable and value-added products were manufactured following a patented cold uniaxial powder compaction method. In this thesis manuscript, the various steps of developing the IWB ceramic were presented. The optimal conditions for preparing dense shaped IWB ceramic in a simple geometry (cylinder) were discussed. Comprehensive characterizations of chemical, physical, thermal, and mechanical properties were conducted. The IWB ceramics prepared under optimal conditions were found to exhibit appropriate bulk density and water absorption of 3.08 g/cm3 and 1.2%, respectively. Moreover, they have revealed good specific heat capacity values of 820-1047 (J/(kg.K)) in the temperature range of (50-1000 ℃), and high mechanical strength of 39 MPa. This work confirms the feasibility of manufacturing TES ceramics out of EAF steel slags, using equipment and techniques well-known in the refractory industry.
Date of AwardMay 2021
Original languageAmerican English

Keywords

  • Concentrated solar power; High-temperature thermal energy storage; Industrial solid waste; Ceramics.

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