COMPARISON OF STRUCTURAL MODELS FOR HIGH-ASH CHAR GASIFICATION

Structural models for the gasification of high-ash char are developed from different approaches to the depiction of the char pore structure. The description of the pore structure of a high-ash char particle is based on the structural characteristics of high-ash containing coal re ject char. A finite overlapping grain model (FOG), modified random por e model (MRP) and a model based on the percolation theory on Bethe lat tice (PBL) are formulated. These models take into account the effect o f ash content by considering it as an inactive inclusion. Comparisons of these models are present based on the parametric simulation results . It has been shown that both the MRP and PBL models can predict simil ar behavior of high-ash char gasification. The effect of ash content o n the surface area and reaction rate evolution is shown to be signific ant. The percolation model has an advantage in that it can describe th e closed pore evolution and predict particle fragmentation.