“…It has been reported that highly aliphatic liptinite and vitrinite macerals in the caking coal contribute significantly to the formation of metaplast (liquid-molten vitrinite), and in the plastic temperature range (350–550 °C) to the development of fluidity and swelling, hence caking. The included kaolinite, submicron minerals associated within macerals (for example, pyrite (FeS 2 ), siderite (FeCO 3 ), calcite (CaCO 3 ), and dolomite (CaMg(CO 3 ) 2 )) and organically associated inorganic elements in the coal react with each other to form artifact minerals at temperatures less than 500 °C. , The polluting gases, i.e., H 2 S, COS, and SO 2 , are released from the sulfur-bearing compounds (organic sulfur and sulfur-bearing minerals) during the pyrolysis of coal under inert atmospheres . Pyrolysis controls the char quality and the pyrolysis mechanisms depending on a number of coal properties that have been studied extensively. − The coal properties of important gasification and combustion technologies include coal rank, coal petrographic, and mineralogical composition; caking propensity, and operating parameters (particle size, temperature, heating rate, pressure, and operating atmosphere). − In addition, during pyrolysis, the plasticity of the caking coal mass is mostly seen at temperatures ranging between 400 and 500 °C. , The caking propensity of caking coal with high proportions of vitrinite- and liptinite-containing functional groups could initiate caking, which is an inevitable technical problem that occurs in fixed-bed coal gasification. − Caking coal particles can soften, swell, and coalesce (forming large cakes) in the fixed-bed gasifier during the gasification process. − This subsequently reduces gas flow and causes channeling and an unstable operating pressure leading to degraded syngas quality.…”