Sammendrag
In this work gasification of char is studied in a simulation code that includes a detailed 22 step heterogeneous
reaction mechanism for char reactivity with CO2, H2O and O2, and uses GRI-Mech 3.0 as the
chemical kinetic mechanism that describes the impact of homogeneous reactions. The code is transient
and zero dimensional in space, and is designed to be used both as a stand-alone gasification/combustion
code and as a sub-model for heterogeneous reactions of solid particles in a CFD code both when the
particle evolution is described by Lagrangian particle tracking and when an Eulerian-Eulerian methodology
is chosen.
The main results for gasification of Wyodak coal char, in an environment similar to a full scale gasification
reactor, are presented. It is shown that for many applications, it is important to account for
inter-particle radiation, i.e. it is not sufficient to consider only radiative heat exchange between the
particle and the surrounding wall, radiation between particles should be considered as well. Account is
made for CO and H2 inhibition in the model, and is shown to significantly affect char reactivity rates.
The inhibition is due to CO or H2 either blocking free carbon sites or reacting with adsorbed oxygen.
reaction mechanism for char reactivity with CO2, H2O and O2, and uses GRI-Mech 3.0 as the
chemical kinetic mechanism that describes the impact of homogeneous reactions. The code is transient
and zero dimensional in space, and is designed to be used both as a stand-alone gasification/combustion
code and as a sub-model for heterogeneous reactions of solid particles in a CFD code both when the
particle evolution is described by Lagrangian particle tracking and when an Eulerian-Eulerian methodology
is chosen.
The main results for gasification of Wyodak coal char, in an environment similar to a full scale gasification
reactor, are presented. It is shown that for many applications, it is important to account for
inter-particle radiation, i.e. it is not sufficient to consider only radiative heat exchange between the
particle and the surrounding wall, radiation between particles should be considered as well. Account is
made for CO and H2 inhibition in the model, and is shown to significantly affect char reactivity rates.
The inhibition is due to CO or H2 either blocking free carbon sites or reacting with adsorbed oxygen.