Since 2011, The Society of Chemical Engineers, Japan (SCEJ) has selected an energy-consuming ethylene plant, aiming at elucidating the mechanism and preventing measures against coking dirt of thermal decomposition above 800 ^oC, which inhibits continuous operation, and polymerization dirt in medium temperature distillation systems. The activities were carried out by forming an industry-academia collaboration consortium of multiple companies and multiple universities and national research institutions. We would like to report the results and lead to new industry-academia collaboration technology innovation.