Modelling of Ethylene Cracker

The major operation problem in steam cracking industry is coke formation and equipments. Ethylene producers have been actively seeking ways to reduce coke formation in order to achieve longer furnace run length. Nowadays many efforts have been made by academics and industrial personnel to understand the coking problem. Numerous techniques have been considered on how to reduce coke formation and/or coke collection on the inner surfaces of the coils in furnaces producing ethylene, propylene, etc. Such reduction would lead to several beneficial events including much reduced production costs. All ethylene furnaces until about 10 years ago had to be decoked after 30-60 days to remove the coke that collected in the coil. Such coke has several adverse effects. First yields of ethylene and other desired hydrocarbons are reduced. Second resistances to heat transfer from the hot combustion gases to the hydrocarbon gases being cracked increase. Hence, energy demands for operating the furnaces increase. Third, resistances to the gas flow in the coils increases as the thickness of the coke increases. Fourth when the furnaces are decoked, production of the desired products is stopped for significant time periods. Due to this consideration, the project was planned to increase the run length by minimizing the formation of coke.