Research And Development On Rotary Air Preheater For Adapting High Inlet Gas Temperaeture(500?)

For a long time,the hot end of air preheater uses common Q235 grade materials,adopting allows metal temperature is 400 ?,allowing the highest flue gas inlet temperature is 420 ?.Under the condition of the limit,air preheater can achieve the highest primary air temperature about 380 ?.In the coal pulverizing system of boiler fuel for high moisture lignite,high ash in inferior coal,lean coal,anthracite)due to low volatile,the temperature often cannot meet the need of drying fuel need or achieve pulverized coal temperature,Boiler system need to adopt to a wind mixed with auxiliary means such as high temperature flue gas to improve the primary air temperature,complicates the boiler system,improve the cost of a boiler system.And if the hot end of preheater to withstand temperature ability to improve,can reduce the system cost and simplify the system,only need to use ordinary boiler smoke wind system layout scheme can achieve a goal.The most demanding of primary air temperature is high moisture lignite,usually require a wind temperature above 400 ?,and at low boiler load stage to also want to meet this requirement.At high load,a wind to 400-450 ? temperature range,according to the heat transfer characteristics of preheater,will choose in preheater inlet smoke temperature 500 ?,can provide the highest temperature is about 450-480 ? of hot wind temperature,meet the needs of the moisture content in 40% or so of the lignite heating,basically covering the domestic high moisture lignite resource,to other high ash and difficult burning of coal,coal for higher fuel preheating temperature,at this time also need higher secondary air temperature,at the same time also need higher inlet flue gas temperature.