Abstract: In a circulating fluidized bed cold model experiment device, the differential pressure fluctuation features and its influence on pressure fluctuation inside the riser when the particles flow through valve were measured and analyzed, by adjusting the superficial gas velocity in the riser and valve of feed returning pipe. The experimental results show that with the decrease of the superficial gas velocity in the riser or the increase of the valve opening, the particles appear in the form of "stock discharge" and "continuous discharge" successively. The "stock discharge" causes larger standard deviation of the pressure difference pulsation of the valve and tends to a single dominant frequency, around 0.35 Hz. While the "continuous discharge" has a smaller standard deviation of the particles differential pressure fluctuation relatively and appears a double frequency, corresponding to 0.35 Hz and 2.5 Hz, and the late frequency has a higher energy. Differential pressure pulsation when the partials flow through the valve directly affects the pressure pulsation behavior inside the riser especially in the lower part of the riser, and their frequency distribution of the pulse is consistent.

Key words: circulating fluidized bed, feed back, particles flowing through valve, differential pressure fluctuation, riser