(2) The circulating rate of the water wall of the once-through boiler with supercritical pressure is equal to 1., and the heat storage capacity of the water wall is relatively weak, which is prone to heat transfer deterioration, especially the second type of heat transfer deterioration. Therefore, it is necessary to reduce the design value of avoiding heat load qR in the burner area as much as possible.
(3) The supercritical once-through boiler can also adopt the spiral coil water wall, which can eliminate the thermal deviation of the water wall along the horizontal direction of the furnace. This characteristic of spiral coil water wall can bring great convenience to the arrangement of burner. For example, the heat load of the "hot corner" of the once-through burner will be higher than that of the "cold corner", and this difference will be eliminated in the water wall of the spiral coil. However, the circulation ratio of the water wall of the spiral coil is also equal to 1., so the vertical distance between the primary air nozzles of the once-through burner and the horizontal and vertical distance between the swirl burners must be large enough, otherwise the heat transfer deterioration of the water wall will also occur.