In contrast to traditional coal separation, dry separation does not require water and does not cause water pollution. Dense phase gas–solid fluidized beds are used for dry separation. The plugged holes in the air distributor should be tested to ensure the stability of these beds for particle separation. The pressure fluctuation is sensitive to these plugged holes. This sensitivity can be tested and diagnosed by determining the standard deviation of the pressure fluctuation. In areas with partial blockage, that is the areas with weak fluidization, a decrease in the volume fraction of the particles and in the pressure differences in the transverse of the bed results in an increase of the standard deviation of the pressure fluctuation, thereby stimulating the lateral mixing of medium-sized particles. The standard deviation and the mixing intensity decrease axially. The value of sensitivity of the plugged holes in the air distributor decreases as the height of the bed increases. The features of air distributors affect the surrounding areas. The distribution law determining the influence of plugged holes on the beds is symmetrical. As the blockage of the fluidized bed distributor region increases, the mean square error of the pressure fluctuation in the related regions increases. The intensity of the effect is proportional to the distance to the plugged holes.