Perpustakaan Digital ITB

Sustainable power generation holds promising potential to combat global warming, air pollution and energy shortages. An example used by power plants to achieve this purpose is co-firing. By using co-firing, the operator can use different fuels within the desired composition, allowing the process to be tailored to demand while optimizing energy supply and demand. Co-firing process in this study is by evaluating a computational fluid dynamic model of the furnace’s combustion running on a mixture of sawdust and coal. The result of this study is to better understand combustion in co-firing by comparing which configuration of the burner in a hexahedral or square configuration is better for achieving a higher temperature and other parameters affecting the co-firing. This study utilized various fuel compositions in the simulation of a co-firing and a single type of fuel firing, which are 100% coal, 100% wood, 85% coal plus 15% sawdust, and 95% coal plus 5% sawdust composition with the identical mass flow and other conditions at the inlet. Most of the fuel composition used in this simulation is from pure curiosity, but the composition of 5% sawdust and 95% coal is from the real-life power plant test conditions. The simulation has two computational domain configurations; the first domain comprises an infinite array of burners, and the second domain corresponds to a real boiler geometry with an adiabatic wall as the boundary condition of the wall. Besides boundary conditions, other parameters are the k-epsilon model for turbulence modelling, the P1 radiation model, transport functions with the volumetric model, eddy dissipation, and inlet diffusion for fuel/chemical reactions. From the simulation results, the trend of the hexahedral burner configuration has higher turbulence kinetic energy, as shown in the boiler combustion model, which is 47.67 J/kg, around 60% higher than the inline configuration of 29.72 J/kg in the boiler combustion chamber. The higher turbulence kinetic energy means that fuel mixing in a hexahedral configuration is better than in an inline configuration, which leads to less burnout than in an inline configuration. Although the trend of using hexahedral configuration has minor burnout, the heat generated and the maximum temperature are also smaller than in the inline configuration. From the simulation result, essential parameters such as turbulent kinetic energy, burnout, and mass source are shown for the user to decide which configuration will they use in the actual case.