Abstract: There were many problems such as lower process gas temperature, tube distortion or burst in heat exchanger during the operation of dry ice expanded tobacco system, the causes were that:1)serious dust buildup in the heat exchanger, which resulted in uneven heat exchange;2)tube corrosion caused by flue gas, cycled process gas and high temperature, which resulted in lower heat exchange efficiency, tube distortion or burst.20 tubes were added in the heat exchanger to increase heat exchange surface;and the 2 longitudinal flanges were replaced by detachable flanges.After improving, the required maintenance interval was achieved, heat loss was reduced, and it was also convenient to inspect and maintain the tubes.