Study of Thermal Degradation of Adipic Acid as PCM under Stress Conditions: A Kinetic Analysis
Abstract
The storage of thermal energy is a key component in some domestic and industrial processes as well as in power generation systems. It ensures system reliability, power dispatchability, and economic profitability. The latent heat technology based on phase change materials (PCM) is a method of thermal energy storage (TES) that it has gained renewed attention in recent years owing to its high thermal storage capacity, operational simplicity, and transformative industrial potential. Adipic acid is a PCM with a melting temperature of 425.1 K, which makes it very interesting for mid-temperature applications. Hence, performing a thermal degradation analysis on this PCM is crucial for ensuring its long-term performance under operating conditions. For this purpose, a kinetic analysis of TGA measurements has been carried out together with isothermal tests under stress conditions in an oven. In a preliminary analysis of TGA results the activation energy was calculated by using an isoconversional method and two degradation mechanisms were observed. Isothermal tests were also analyzed so that the corresponding activation energy was obtained as well. However, the strong difference observed between the energies obtained from both cases demonstrates that both kinetic analyses must be carefully improved.