Session: 11-01: Process Heat for Desalination and Industrial Decarbonization

Paper Number: 138373

138373 - Experimental Evaluation of Waste Foundry Sand-Based Composite Pcm Systems for Industrial Process Waste Heat Recovery 

Abstract: 

This study introduces a new use case for waste foundry sand (WFS), a by-product of metal casting processes. WFS, typically discarded after limited reuse in casting, poses both economic and environmental challenges due to high disposal costs and landfill taxes. This research explores the innovative use of WFS as a matrix material in composite phase change materials (CPCMs), offering a novel pathway for recycling this abundant waste product in medium-high-temperature waste heat recovery (WHR) and energy storage applications.

These composites are fabricated through a process involving the mixing of WFS, phase change materials (PCMs), and MgO, followed by milling, compression into cylindrical pucks, and sintering. This sintering process heats the material to temperatures approximately 100°C higher than the melting point of the corresponding PCM.

Two PCMs, NaNO3 and solar salt, were selected as the phase change materials for the composite phase change materials (CPCMs). these PCMs have sequential melting points—308°C for NaNO3 and 220°C for solar salt—making them ideal for a cascade system that can utilize a broad temperature range efficiently. The formulated CPCMs, comprising a mass ratio of 0.4 WFS, 0.2 MgO, and 0.4 PCM. They were in the form of cylindrical pellets (60 mm in diameter and 50 mm in height).  The CPCMS were found to be structurally and chemically stable after subjection to thermal cycling. Their energy storage density was determined to be 516 and 542 kJ/kg the NaNO3 and solar salt based CPCMs, respectively. A total of 1890 CPCMs were loaded in a packed bed storage system with a resulting capacity of 262 MJ.

The system's testing was specifically designed to simulate the capture of waste heat from casting induction furnaces, operating at around 400°C, and its potential reuse in space heating applications. The experimental setup revealed a well-controlled charging process, with distinct thermal behaviors noted across the tank's thermocouples. The charging efficiency was within the expected range, while the discharge efficiency indicated a robust performance, albeit with some potential for optimization. Overall, the system's total efficiency was approximately 68%. The system's performance during free cooling also indicated its suitability for intraday applications, as no significant losses were observed during overnight idle periods.

This study not only introduces a novel approach to thermal energy storage but also significantly contributes to industrial decarbonization efforts through sustainable advanced waste management. By effectively utilizing WFS in thermal energy systems, this research offers a cost-effective and eco-friendly sustainable WHR solutions.

Presenting Author: Argyrios Anagnostopoulos Aristotle University of Thessaloniki

Presenting Author Biography: Dr. Argyrios Anagnostopoulos is currently a Marie Curie Postdoctoral Fellow at a joint program between the Aristotle University of Thessaloniki and the University of Birmingham. He specializes in Thermal Energy Storage (TES) systems with particular emphasis on medium-high temperature latent heat storage using molten salts. He has a bottom-to-top knowledge of the field ranging from material characterization to device modelling and life cycle analysis. He is the corresponding author of 15 and co-author of 6 peer-reviewed papers in highly rated journals in the field of energy and waste valorisation. He is the co-author of an RSC Book chapter on TES material modelling. He also has a pending patent application on a novel fabrication method of composite phase change materials for thermal energy storage. He obtained his PhD in 2020 from the University of Birmingham, School of Chemical Engineering after graduating from the University of Surrey (MSc in Renewable Energy Systems Engineering, Department of Chemical & Process Engineering).

Authors:

Abdalqader Ahmad University of Birmingham
Argyrios Anagnostopoulos Aristotle University of Thessaloniki
Helena Navarro University of Birmingham
Yelaman Maksum University of Birmingham
Shivangi Sharma University of Birmingham
Yulong Ding University of Birmingham