“…Modeling and optimization of gas-solid reactors has been studied extensively (Schaefer et al, 1974;Cumming and Thurlby, 1990;Rovaglio et al, 1994;Cross and Blot, 1999;Sadri et al, 2007) and it is difficult to review the entire subject in detail here. The author has been involved in the development of mathematical models for industrial scale gas-solid reactors, related software tools (Virtual Sinter TM , Virtual Indurator TM and DRIKS TM ) and their application for various industrial problems, for example, sintering of iron ore fines (Venkataramana et al, 1997(Venkataramana et al, , 1998(Venkataramana et al, , 1999(Venkataramana et al, , 2002Gupta and Runkana, 2000;Kapur and Runkana, 2003), induration of iron ore pellets on a traveling grate Mitra et al, 2009;Cavalcante et al, 2012;Runkana and Majumder, 2013), direct reduction of iron ore by coal in a rotary kiln (Runkana et al, 2007;, 2010c, and calcination of limestone in a vertical shaft kiln, etc. The objective here is to share this knowledge of model development incorporating important physico-chemical phenomena, simulation and optimization techniques employed and details of their demonstration for a couple of industrial cases.…”