Abdessamad Faik

New Thermal Energy Storage Materials From Industrial Wastes: Compatibility of Steel Slag With the Most Common Heat Transfer Fluids

Slag is one of the main waste materials of the iron and steel manufacturing. Every year about 20 × 106 tons of slag are generated in the U.S. and 43.5 × 106 tons in Europe. The valorization of this by-product as heat storage material in thermal energy storage (TES) systems has numerous advantages which include the possibility to extend the working temperature range up to 1000 °C, the reduction of the system cost, and at the same time, the decrease of the quantity of waste in the iron and steel industry. In this paper, two different electric arc furnace (EAF) slags from two companies located in the Basque Country (Spain) are studied. Their thermal stability and compatibility in direct contact with the most common heat transfer fluids (HTFs) used in the concentrated solar power (CSP) plants are analyzed. The experiments have been designed in order to cover a wide range of temperature up to the maximum operation temperature of 1000 °C corresponding to the future generation of CSP plants. In particular, three different fluids have been studied: synthetic oil (Syltherm 800®) at 400 °C, molten salt (Solar Salt) at 500 °C, and air at 1000 °C. In addition, a complete characterization of the studied slags and fluids used in the experiments is presented showing the behavior of these materials after 500 hr laboratory-tests.

New Thermal Energy Storage Materials From Industrial Wastes: Compatibility of Steel Slags With the Most Common Heat Transfer Fluids

Slag is one of the main waste materials of the iron and steel manufacturing. Every year about 20 million tons of slag are generated in the United States and 43.5 million tons in Europe. The revalorization of this by-product as heat storage material in thermal energy storage systems would have numerous advantages which include: the possibility to extend the working temperature range up to 1000 °C, the reduction of the system cost and, at the same time, the decrease of the quantity of waste in the iron and steel industry.In this paper, two different electric arc furnace slags from two companies located in the Basque Country (Spain) are studied. Their thermal stability and compatibility in direct contact with the most common heat transfer fluids used in the concentrated solar power plants are analyzed. The experiments have been designed in order to cover a wide temperature range up to the maximum operation temperature of the future generation of concentrated solar power plants (1000 °C). In particular, three different fluids have been studied: synthetic oil (Syltherm 800®) at 400 °C, molten salt (Solar Salt) at 500 °C and air at 1000 °C. In addition, a complete characterization of the studied slags and fluids used in the experiments is presented showing the behavior of these materials after 500 hour laboratory-tests.Copyright

Parametric analysis of a packed bed thermal energy storage system

Even if the packed bed thermal energy storage concept has been introduced as a promising technology in the concentrated solar power field in the last years, its full deployment in commercial plants presents a clear improvement potential. In order to overcome the under-development of this storage technology, this work attempts to show the great capabilities of packed bed heat storage units after a successful design and operational parametric optimization procedure. The obtained results show that a correct design of this type of facilities together with a successful operation method, allow to increase significantly the storage capacity reaching an overall efficiency higher than 80 %. The design guideline obtained as a result of this work could open new objectives and applications for the packed bed storage technology as it represents a cost-effective and highly performing storage alternative.Even if the packed bed thermal energy storage concept has been introduced as a promising technology in the concentrated solar power field in the last years, its full deployment in commercial plants presents a clear improvement potential. In order to overcome the under-development of this storage technology, this work attempts to show the great capabilities of packed bed heat storage units after a successful design and operational parametric optimization procedure. The obtained results show that a correct design of this type of facilities together with a successful operation method, allow to increase significantly the storage capacity reaching an overall efficiency higher than 80 %. The design guideline obtained as a result of this work could open new objectives and applications for the packed bed storage technology as it represents a cost-effective and highly performing storage alternative.

Experimental investigation of solid by-product as sensible heat storage material: Characterization and corrosion study

The experimental investigation of water cooled electrical arc furnace (EAF) slag used as filler material in the storage tank for sensible heat storage application was demonstrated in this study. The physicochemical and thermal properties of the tested slags were characterized by using X-ray diffraction, scanning electron microcopy, Fourier transform infrared spectroscopy, Raman spectroscopy and laser flash analysis, respectively. In addition, the chemical compatibility between slags and molten nitrate salt (60 wt. % NaNO3 and 40 wt. % KNO3) was investigated at 565 °C for 500 hrs. The obtained results were clearly demonstrated that the slags showed a good corrosion resistance in direct contact with molten salt at elevated temperature. The present study was clearly indicated that a low-cost filler material used in the storage tank can significantly reduce the overall required quantities of the relatively higher cost molten salt and consequently reduce the overall cost of the electricity production.

Parametric and Thermal Management Optimization of a Steel Slag Based Packed Bed Heat Storage

In this work steel slag, one of the main by-products of the steelmaking industry, is proposed as a competitive and effective heat storage material. The implemented storage design suggested for this material is a solid packed bed arrangement based in the temperature stratification (thermocline) phenomena. In particular, two different solutions based on different storage tank geometries, cylindrical and conical, have been modeled by using computational fluid dynamic (CFD) methods. In addition, both geometries have been simulated under two different operation modes as a function of the used heat transfer fluid: solar salt and air. This selection permitted to investigate the operation of the proposed storage for current CSP technologies which make use of molten salt as storage/heat transfer fluid and also the analysis of the system when the operation parameters are potentially associated to new generation CSP plants at higher temperatures, above 600 °C. The comparison between the simulated systems has allowed to determine the influence of the driving parameters on the proposed storage solution, such as the operation temperature range, nature of the heat transfer fluid or geometrical implications. The thermal management of the storage unit has also been shown during a transient operation up to a reproducible behavior.Overall, the selected parameters for the presented modeling analysis have revealed the high potential of steel slag as heat storage material and the suitability and flexibility of the implemented packed bed solution.Copyright

Post-Industrial Ceramics Compatibility With Heat Transfer Fluids for Low-Cost Thermal Energy Storage Applications in CSP

This paper investigates the possibility of using a post-industrial ceramic commercially called Cofalit as a promising, sustainable, and inexpensive (

Corrosion effects between molten salts and thermal storage material for concentrated solar power plants

10/ton) thermal energy storage material. This ceramic presents relevant properties to store thermal energy by means of sensible heat in the temperature range of concentrated solar power (CSP) plants from ambient temperature up to 1100 °C. In the present study, the compatibility of this ceramic was studied with two conventional heat transfer fluids: nitrate molten salts for medium-temperature applications (200 to 500 °C) and air for high-temperature applications (500 to 900 °C). The use of this ceramic in direct contact with the heat transfer fluid should significantly reduce the cost of thermal energy storage systems in CSP applications and help to achieve the U.S. Department of Energy’s SunShot Initiative cost targets.Copyright