78 Chapter VI Conclusions and Recommendations VI.1 Conclusions Based on the results of the simulation and analysis of the combustion of a natural gas and ammonia mixture on the Rolls Royce B35:40V20A2 engine, focusing on combustion characteristics, engine performance, and emission characteristics, the following conclusions can be drawn from this thesis research. 1. The combustion of a natural gas and ammonia mixture demonstrates stability in combustion across all tested molar fractions while the ignition delay remains consistently within a stable range not exceeding 2.94%, combustion duration exhibits consistency with variations below 2%, MHRR reflects stability with changes not surpassing 7.94%, farther both combustion temperature and pressure maintain stability with respective changes not exceeding 3.72% and 2.15%. 2. The combustion of a natural gas and ammonia mixture results engine performance stability with variations in power output remaining below 1% across all ammonia molar fractions,, the thermal efficiency experiences a change not exceeding 1.32%, while the SFC significantly increases, reaching three times the original value due to the characteristics of ammonia which requires less combustion air and has a lower calorific value compared to methane, leading to an increased mass flow rate of ammonia. 3. The emission characteristics observed during the combustion of a natural gas and ammonia mixture indicate a significant reduction in CO and CO2 emissions achieving zero emissions at 100% ammonia concentration, conversely, NOx emissions exhibit an increasing trend reach 81.40% with 50% ammonia fraction followed by a decline that results in a 9.09% emission level (above pure natural gas) at 100% ammonia while NOx reduction procedures is essential to meet the emission standards established in Indonesia. The addition of the ammonia mole fraction showed a decrease in Total CO2 emissions equivalent by 25.04% in the 50% ammonia fraction and 90.10% in the 100% ammonia mole fraction. 79 4. The findings from the simulation study on the combustion of a natural gas and ammonia mixture suggest that an ammonia mole fraction range of 10% to 50% is recommended to achieve an optimal balance among combustion stability, engine performance, and emission characteristics in the Rolls Royce B35:40V20A2 engine. VI.2 Recommendations Based on the research presented, further development is necessary to prepare for the implementation of ammonia co-firing in PLTMG. Several recommendations are proposed to enhance similar research in the future, including: 1. Conducting simulations with variations in ignition timing to achieve optimal combustion, thereby maximizing power output while ensuring more efficient fuel consumption. 2. Carrying out an economic analysis regarding the addition of ammonia molar fraction in the combinde-combustion of natural gas and ammonia. 3. Analyzing the material resilience and performance of supporting components in the engine in response to phenomena occurring, particularly the average temperature and maximum pressure changes within the cylinder, as well as the potential for corrosion damage in the engine when using ammonia as a fuel..