Abstract:
A number of studies have been carried out for the combustion of coal by different types of model
i.e. shrinking core model, shrinking reactive coal model, random pore model, etc. Some of them
are briefed as follows.
Everson et al. [9]in their paper have studied about char combustion under pressurized fluidized
bed combustion process, and overall study of char combustion model is done. They used high
ash content char particle for their study.The ash content was above 40% and calorific value was
low. They used PBFC(pressurized fluidized bed combustion)in place of PFC(pulverized fuel
combustors) because PFC has some disadvantages such as pollutant concentration is high and are
technically difficult to handle. For experimental results,Thermo Gravimetric Analyzer (TGA)was
used and experimental data was compared with model equation predictions. Experiments were
carried out at 487kPa and temperature in therange from 750°Cto 950°C. They introduced the
concept of variation in carbon concentrationfor showing the effect of high ash content. The
model which they used for combustion process was shrinking reactive core model and
experimental data agreed well with this model. Experimental results at different temperature and
pressure were compared with model and effects of various parameters such as conversion
withtime were discussed. In their investigation, they found that at higher temperature, value of
Thiele modulus was large, it was not sufficient enough to describe shrinking core model. At
temperature greater than 950°C, they found that shrinking reactive core model gives exactlythe
same results as obtained from shrinking core model.Following graphs shows the investigation of
different parameters as done by Everson et al. [9
