The utility model discloses a modular steam generator, sealed tank body including the circulation vapour, sealed tank body's top nestification has the drum, the mouth that advances that links up sealed tank body is seted up to the one end of drum, the outlet flue that links up sealed tank body is seted up to the other end of drum, evenly arrange and absorb steam heat's waste heat flue gas heat exchange tube in the inside of drum, install the organic heat carrier heat exchange tube on sealed tank body's the inner wall, sealed tank body's side is provided with the pressure transmitter of being convenient for the organic heat carrier supply, moreover, the steam generator is simple in structure, can retrieve the heat in the vapour, the heat of retrieving utilizes again, the pollution of vapour to the environment has been reduced, and practicality is excellent, be convenient for control equipment, the elevating mast utilization ratio, novel design is achieved, is a good innovative scheme, the double -motor disassembling -and -washing -free smoke ventilator has a very good market prospect.