Compared with the free bed, the gas?solid fluidized bed with rotating sieve tray type baffles has good performance in breaking the bubbles under different superficial gas velocities (Ug=0.04~1.14 m/s). The ideal operating conditions were then determined by some parameters, e.g. the flow phenomena, the standard deviation of differential pressure fluctuation and the standard deviation of pressure fluctuation. The results showed that, when the superficial gas velocity increased, the particles below the internals tended to move forward to the areas above the internals. It caused the bed height to decrease below the internals. Moreover, three flow types appeared below the internals under different superficial gas velocities. It directly determined if the internals worked in breaking bubbles. When Ug<0.44 m/s, the bed height kept high value below the internals. The bubbling fluidized bed appeared. It contained two sections: the bottom section with dense phase and the upper section with the alternant appearance of the dense phase and the large bubbles. At that time, the internals suppressed the growth of bubbles and can even break the bubbles. Compared with the free bed, the fludized bed with internals had lower standard deviation of differential pressure fluctuation and the standard deviation of pressure fluctuation. When 0.44≤Ug<0.66 m/s, the bed height became small below the internals. The turbulent fluidized-bed occurred. It included two sections: the bottom section with dense phase and the upper section with dilute phase. At that time, the internals had no direct influence on the bubbles. However, the dense phase at bottom reduced the pressure fluctuation intensity below the internals and a little above the internals. When Ug≥0.66 m/s, the turbulent fluidized-bed comprised one single section with dilute phase. The section with dense phase disappeared. The gas phase became the continuous phase below the internals. At that time, the internals had little influence on the bubbles, the bed pressure and the differential pressure fluctuation intensity.
Yao SHI Dewu WANG Bin ZHAO Shaofeng ZHANG Kaiguang LIANG Shuhui MA
. Pressure fluctuations in a gas-solid fluidized bed with rotating sieve tray type baffles[J]. The Chinese Journal of Process Engineering, 2019
, 19(1)
: 91
-101
.
DOI: 10.12034/j.issn.1009-606X.218151
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