NUMERICAL STUDY OF PREMIXED AMMONIA-HYDROGEN-NITROGEN-AIR COMBUSTION FROM PARTIAL AMMONIA DECOMPOSITION

• Main Author: Afif Ma'ani, Fachriza
• Format: Final Project
• Language: Indonesia
• Subjects: Teknik (Rekayasa, enjinering dan kegiatan berkaitan)
• Online Access: https://digilib.itb.ac.id/gdl/view/74237
• Institution: Institut Teknologi Bandung

Most power generation uses a thermal process to generate the energy required through the combustion process of carbon-based fuel. Carbon-based fuel combustion from power generation produces large amounts of CO2 and has become a major contributor to global warming. Ammonia and hydrogen have the potential to be used as alternative fuels to reach a zero-emission target in 2050. Hydrogen combustion has several challenges because of its properties, which are highly flammable and low density to storage. In contrast, ammonia is widely available and has a high hydrogen content, but ammonia is slightly flammable. Ammonia can be used as a hydrogen carrier through a partial decomposition process. The combustion process of partial ammonia decomposition needs to be studied first, especially the NOx production due to the nitrogen in the fuel mixture. In this study, the premixed combustion simulation of partial ammonia decomposition was carried out through Computational Fluid Dynamics (CFD) with ANSYS Fluent software. The reduced GRI-Mech 3.0 chemical reaction mechanism was used to simulate the combustion process. The equivalence ratio was variated from 0.2 to 1.4 with an incremental of 0.1. The analysis result showed that the level of NOx emissions is very high from very lean combustion to lean combustion, which is above 400 mg/Nm3. The thermal and prompt NOx were significant in forming NOx emissions under very lean and lean combustion. The level of NOx emission further decreases with increasing equivalence ratio towards rich combustion, starting from an equivalence ratio of 1 with a value below 400 mg/Nm3, demonstrating a strong fuel potential with ammonia and hydrogen. The NH2 radical molecules were found to be significant in the reduction of NOx emissions at rich combustion.