| 摘要 |
PURPOSE: To avoid the high-temperature corrosion as well as the low-temperature corrosion of an air preheater by a method wherein a part of air, preheated in a first air preheater while avoiding a zone serious in the high-temperature corrosion, is supplied to a second air preheater to obtain preheated air while heating so that the temperature of an air inlet pipe wall becomes higher than an acid dew point temperature. CONSTITUTION: Air supplied by a fan 6, is supplied to a first air preheater 7 to be preheated by the combustion waste gas from an incinerator 2, then, a part of the gas is supplied to a second air preheater 10 while the balance of the gas is joined with the outlet air of the second air preheater 10 through a bypass duct 11 and a bypass control valve 12. The temperature of a pipe wall of the air outlet side of the first air preheater 7, which is contacted with gas, is controlled so as to avoid a range, serious in high-temperature gas corrosion, while the temperature of a pipe wall of the air inlet side of the second air preheater 10, which is contacted with the gas, is controlled so as to be heated to a temperature higher than the temperature of low-temperature corrosion. Control is effected by TIC while detecting the air outlet side gas part pipe wall temperature, a mixed preheating air temperature, an waste gas outlet temperature and the like to effect an operation while the flow rate of air or preheated air are regulated by the bypass control valve. |
