Process for producing conjugated diene

The present invention relates to a process for producing a conjugated diene, the process comprising a reaction step in which a starting-material gas comprising a C4 or higher monoolefin is oxidized and dehydrogenated with a molecular-oxygen-containing gas in the presence of a catalyst to obtain a conjugated-diene-containing reaction product gas and a cooling step in which the reaction product gas is cooled. In the cooling step, a coolant is supplied to a cooling tower to bring the coolant into contact with the reaction product gas, and the coolant discharged from the cooling tower is then cooled by a heat exchanger to cause precipitable substances dissolved in the coolant to precipitate within the heat exchanger, the precipitates being recovered. The coolant from which the precipitates were recovered is circulated to the cooling tower. 本发明涉及种共轭二烯的制造方法，该方法包括：在催化剂存在下，利用含分子态氧的气体使含有碳原子数4以上的单烯烃的原料气体进行氧化脱氢反应，得到含有共轭二烯的反应生成气体的反应工序；以及，对所述反应生成气体进行冷却的冷却工序，其中，在所述冷却工序中，将冷却剂供给至冷却塔并使其与反应生成气体接触，然后通过热交换器对从所述冷却塔排出的冷却剂进行冷却，使溶存于