Steam discharge waste heat utilization system of condensing type small turbine for driving induced draft fan

A steam discharge waste heat utilization system of a condensing type small turbine for driving an induced draft fan comprises a main turbine and the condensing small turbine connected with the induced draft fan. The steam outlet of the small turbine is connected with the condenser of the small turbine. The steam outlet of the main turbine is sequentially communicated with a mainframe condenser, a condensing water pump, a condensate polishing device, a shaft-sealing condenser and a low-pressure regenerative system. The outlet of the shaft-sealing condenser and the condensate outlet pipeline of the condenser of the small turbine converge at a condensate return pipeline. The outlet of the condensate return pipeline is connected with the low-pressure regenerative system. The steam discharge and waste heat utilization system has the advantages that mainframe condensate is used as the cooling water source of the condenser of the small turbine, steam discharge waste heat of the small turbine can be fully recycled, total system cold source loss is reduced, and the system is relatively simple, small in operation and maintenance workload, and universal for water cooling units and air cooling units.