23 Chapter III Methodology III.1 Research Workflow The research workflow will be conducted in several stages as shown in Figure III.2. The initial stage involves an extensive literature review of relevant papers, journals, and books to gather comprehensive information on ammonia combustion, natural gas properties, and co-firing techniques in gas engines. This review will also encompass experimental data, previous research reports, and emission acceptance criteria to establish a solid foundation for the study. Figure III.1 Gas Engine at PLTMG Luwuk 40MW. Following the literature review, the next step is data collection, which includes gathering research data, limitations, and assumptions relevant to the study. These data will be used to model a Rolls-Royce B35:40V20A2 gas engine (Figure III.1) in PLTMG Luwuk 40MW Project using ANSYS Forte software, simulating its operation with 100% natural gas as fuel. The model's validity will be assessed by comparing the simulation results with actual research data for the same engine running on 100% natural gas. If the validation error is less than 10%, the model will be deemed accurate and suitable for further analysis. 24 Figure III.2 Research workflow. Upon successful model validation, the research will proceed to the simulation of combustion combinations using varying ammonia fractions (5-100%, in 5% increments) in the Rolls-Royce B35:40V20A2 engine model. The simulation results, along with research data, limitations, and assumptions, will then be analyzed to determine the combustion characteristics, engine performance, and emission levels for each ammonia fraction. The subsequent analysis will focus on evaluating the combustion characteristics, engine performance, and emissions data obtained from the simulations. This Paper, journal, book Experiment data, previous research report, emissions acceptance criteria Research data, limitation, assumptions Research data Research data, Limitation, and Assumptions Simulation result, research data, limitation, assumption, and literature review Result Analysis Start Literature Review Data Collection Limitation and Assumption Modelling Rolls-Royce B35:40V20A2 on Ansys Forte (100% natural gas) Model validation Rolls-Royce B35:40V20A2 on Ansys Forte (100% natural gas) Validation Error <10% Combustion Combination Simulation on Ansys Forte (10-100% Ammonia, step 10%) Combustion Characteristic, performance, and emissions Analysis Conclusion and Recommendations Finish Maximum Ammonia mole fraction Recommendation Analysis Combustion characteristic, performance, emission analysis result, limitations and assumptions No Yes 25 analysis will consider research data, limitations, and assumptions to provide a comprehensive understanding of the impact of different ammonia fractions on engine performance. Based on the analysis results, the maximum allowable ammonia mole fraction for the Rolls-Royce B35:40V20A2 engine will be determined. This recommendation will consider the engine's performance, emissions, and operational limitations to ensure optimal and sustainable operation. Finally, the research will conclude with a summary of the findings, including conclusions and recommendations for the practical implementation of ammonia- natural gas co-firing in gas engines. This will contribute to the ongoing efforts to reduce greenhouse gas emissions and promote the use of cleaner fuels in the power generation sector..