Ponugoti, Venkata Prakash
(2016)
Modelling of Coal Devolatilization.
Masters thesis, Indian Institute of Technology Hyderabad.
Abstract
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.
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