Development of a hybrid shrinking‐core shrinking‐particle model for entrained‐flow gasifiers

Slagging entrained‐flow gasifiers operate above the melting temperature of the ash. As slag is highly nonwetting on the surface of char (carbon) particles, it is likely that it will agglomerate into one or several slag droplets and some of these droplets can detach from the char particles. If the slag exists in the form of droplets on the char surface rather than as a solid shell around the unreacted char particle, a shrinking particle model would be more physically realistic representation in comparison to the widely used shrinking core model (SCM). In the early section of the gasifier, the temperature remains below the ash melting temperature and, therefore, the SCM is more appropriate in this region. With this motivation, a novel hybrid shrinking‐core shrinking‐particle model has been developed. The model provides spatial profile of a number of important variables that are not available from the traditional SCM. © 2015 American Institute of Chemical Engineers AIChE J, 62: 659–669, 2016