A new method

which can solve the corrosion problem in wet flue gas desulfuration system

has been presented

namely

a temperature reducing heat exchanger of the tubular type being allocated in front of the electrostatic precipitator（ESP）

making the flue gas temperature to be dropped clown below the dew point

enabling SO3 and water vapor in the flue gas to be condensed into mist

and to be adhered on particles of the fly ash

and then to be removed together with fly ash in the ESP. This method not only can enhance the discharged flue gas temperature

but also can solve the difficult problem of corrosion in downstream of the desulfuration tower. At the same time

the efficiency of ESP can also be enhanced

the economic and environmental benefits to be extraordinarily remarkable.