Modelling of Coal Devolatilization

Pulverized fuel combustor holds a great importance when compared with fluidised bed combustor due to it’s high combustion intensities and high heat transfer rates. The science behind pulverized furnace coal combustion is fairly well understood but the crucial interfaces between devolatilisation, secondary gas phase reactions and char combustion makes it difficult to construct a mathematical model. The modelling of coal combustion with some simplifying assumptions, which can be coupled with furnace module and capable of predicting the exit fuel gas concentrations from a pulverized coal furnace is developed as part of this work. Coal combustion and gasification are complex processes, where devolatilization is always the first step and plays a fundamental role. The key to understanding the phenomena occurring inside the process units thus lies in describing the primary devolatilization and its associated products. It is known that coal devolatilization is a process in which gases, tar, and char are released form coal at elevated temperatures and pressures. Devolatilization is guided by many factors out of which bond strengths of different aromatic and aliphatic molecules plays an important role in formation of tar, gas and char while the stabilization of radicals formed during devolatilization depends the upon amount of hydrogen molecules available, which in turn effects the degradation of coal