Thermodynamic property fields for ammonia storage as hydrogen energy carrier

• Main Author: Lim, Hui Ling
• Other Authors: Anutosh Chakraborty
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2023
• Subjects: Engineering::Mechanical engineering
• Online Access: https://hdl.handle.net/10356/168341
• Institution: Nanyang Technological University

The study also highlights the limitations and challenges of using ammonia as a hydrogen carrier and suggests directions for future research. The study shows that the low adsorption capacity of ammonia limits its practical use for high-density hydrogen storage. The slow kinetics of ammonia-based hydrogen release hinders its application in fuel cells. However, the study suggests that the development of new adsorbents with tailored properties, such as high surface area, selective affinity, and fast diffusion, could overcome these challenges and enable the widespread adoption of ammonia-based hydrogen storage and release. As demand for carbon-free energy grows, hydrogen is a promising alternative to fossil fuels. However, producing, storing, and distributing hydrogen is difficult, particularly due to efficiency, cost, and safety. One way to address these challenges is to use ammonia as a hydrogen carrier but achieving high yield in ammonia-based hydrogen storage and release is tough. To better understand the adsorption of ammonia and hydrogen on different adsorbents, this study investigates their thermodynamic properties. The study looks at entropy, enthalpy, specific heat capacity and isosteric heat of adsorption. The thermodynamic formulations were derived from Sun-Chakraborty and Dubinin–Astakhov isotherms, which are commonly used to model gas-solid physisorption. The study examines a range of temperatures which are relevant to industrial applications. The temperatures examined were from 273K to 323K for ammonia and 230K to 293K for hydrogen. The pressure examined ranged from 0 to 10 MPa. It also compares the performance of several adsorbents including zeolites and metal-organic frameworks.