Abstract: Through the cold dynamic field test on a 300-MW circulating fluidized bed boiler(CFBB), it is discovered that the fluidization around the left and the right manhole doors is extremely poor. When the primary air volume reaches as much as about 280 m3/h, the both sides might reach the critical fluidization state, which is very different from the designed values and affects the safe operation of the boilers with this kind of primary air inlets. Based on the adjustment on the hood holes and the pressure distribution and by virtue of the fluidization uniformity test to determine the high and the low pressure areas, the modification area is fixed. With the help of the theoretical analysis, the resistances of the hoods in the middle of the air chamber are increased by technical means without any changes in the primary air inlets. Therefore, the even air distribution is gradually realized on both sides and in the middle of the air chamber, thus solving the problems such as inadequate fluidization and coking at both sides of the air chamber and improving the boiler efficiency.

Key words: CFBB, air inlet chamber, flow field, air pressure