Non-uniform distribution of gas–solid flow through six parallel cyclones in a CFB system: An experimental study--颗粒学报PARTICUOLOGY

Zhou, X., Cheng, L., Wang, Q., Luo, Z., & Cen, K. (2012). Non-uniform distribution of gas–solid flow through six parallel cyclones in a CFB system: An experimental study. Particuology, 10(2), 170–175. https://doi.org/10.1016/j.partic.2011.10.006

Non-uniform distribution of gas–solid flow through six parallel cyclones in a CFB system: An experimental study

Xinglong Zhou,Leming Cheng^*, Qinhui Wang, Zhongyang Luo, Kefa Cen

State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China

10.1016/j.partic.2011.10.006

Volume 10, Issue 2, April 2012, Pages 170-175

Received 23 July 2011, Revised 15 October 2011, Accepted 21 October 2011, Available online 8 March 2012.

E-mail: lemingc@zju.edu.cn

Highlights

► Six cyclones were located on the left and right walls of the riser in a CFB cold test rig.

► Measurements showed that the middle cyclone on each side had higher particle velocity, but lower solid volume fraction and solid circulating rate than other two cyclones, due mainly to the non-uniform gas–solid flow at the riser outlets.

Abstract

In large-scale circulating fluidized bed (CFB) boilers, it is common to use multiple cyclones in parallel for the capture of solids, assuming that gas–solid flow to be the same in the cyclones. This article presents a study investigating gas–solid flow through six parallel cyclones in a CFB cold test rig. The six cyclones were located asymmetrically on the left and right walls of the riser. Solid volume fraction and particle velocity profiles at the riser outlets and in the horizontal ducts were measured using a fiber optical probe. Cyclone pressure drop and solid circulating rate were measured for each individual cyclone. Measurements showed good agreement as to the non-uniform distribution of the gas–solid flow, which occurred mainly across the three cyclones on one side: the middle cyclones on both sides had higher particle velocities. Conversely, the solid volume fractions, solid fluxes and solid circulating rates of the middle cyclones were lower than those of the other four cyclones. The apparent reason for the flow non-uniformity among the cyclones is the significant flow non-uniformity at the riser outlets. Under typical operating conditions, the solid volume fractions at the riser outlets had a deviation of up to 26% whereas the solid circulating rates at the stand pipes, 7%. These results are consistent with most other studies in the literature.

Graphical abstract

Keywords

Circulating fluidized bed; 600-MW CFB; Parallel cyclone; Solid circulating rate

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