University of Silesia in Katowice

Developing a new system for energy storage with the use of waste vermiculite.

keywords: energy storage, vermiculite, water, ammonium

Thermochemical energy storage (TCS) is a relatively new concept of fundamental importance for contemporary chemistry and environmental engineering as well as sustainable development.

TCS is based on reversible chemical reactions. Among many pairs, the most promising are sorption systems operating in the wide range between -50°C to 150°C. In such reactions, heat is stored or retrieved in the form of chemical or physical bonds between sorbent and sorbate. Commonly used sorbents are salt hydrates, active coals, aluminium phosphate, zeolites, and metal-organic frameworks (MOF); whereas common sorbates are water vapour, ammonium, ethanol, and methanol. Additionally, a porous matrix is used, which promotes chemisorption, and thus, improves the transport of heat and mass, and the kinetics of the reaction.

The significant problem of the TCS is the economic nature of the entire process. One of the researched matrices is vermiculite. Vermiculite has a specific surface area of from 1m²/g to 40m²/g, typically around ~15-20 m²/g, and an average density of 2,5g/cm³.

The goal of the project will be to adapt waste vermiculite, the so-called red mud, as a new system for energy storage. The red mud is a waste of aluminium production with a specific surface area of around 20 m²/g and a density of 3,6 g/cm³. The project carries out research on red mud reactions to check whether the process is reversible and to describe the kinetics of the reaction. Moreover, we modify red mud as potential thermochemical energy storage.