Low-temperature heat utilization system of reaction gas waste heat from fluidized bed for preparing butadiene by oxidative dehydrogenation of butene

The utility model relates to a low-temperature heat utilization system of reaction gas waste heat from a fluidized bed for preparing butadiene by oxidative dehydrogenation of butane. The system comprises two hot water heat exchangers, a settlement tank, an oil isolation tank, a sewage delivery pump and a sewage cooler, wherein the settlement tank is connected with the oil isolation tank by a pipeline; a sewage outlet of the oil isolation tank is communicated with the sewage cooler by a pipeline and the sewage delivery pump; a softened water outlet of each hot water heat exchanger is connected with a rear heat exchanger; the rear heat exchangers are respectively provided with a reaction gas inlet, a reaction gas outlet, a softened water inlet and a softened water outlet; the softened water outlet is connected with a hot water circulating tank by a pipeline; the hot water circulating tank is also provided with a softened water supply hole and a hot water outlet; the hot water outlet is connected with a low-temperature heat utilization system pipeline by a hot water circulating pump; and the other end of the low-temperature heat utilization system is connected with an inlet of the hot water heat exchanger, so that a closed loop circulation pipeline can be formed. The system has the advantages that the waste heat can be fully utilized, and the condensation load of a quench tower is reduced, so that the energy is saved, and the production cost is lowered; and all the working procedures are guaranteed not to be scaled or blocked, so that the environmental pollution is reduced.