Effects of various parameters on the attrition of bed material in a recirculating fluidized bed with a draft tube--颗粒学报PARTICUOLOGY

Chourasia, S., & Alappat, B. J. (2018). Effects of various parameters on the attrition of bed material in a recirculating fluidized bed with a draft tube. Particuology, 38, 61-70. https://doi.org/10.1016/j.partic.2017.05.011

Effects of various parameters on the attrition of bed material in a recirculating fluidized bed with a draft tube

Shivali Chourasia ^*, Babu J. Alappat

Department of Civil Engineering, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India

10.1016/j.partic.2017.05.011

Volume 38, June 2018, Pages 61-70

Received 29 June 2016, Revised 10 April 2017, Accepted 25 May 2017, Available online 4 September 2017, Version of Record 2 April 2018.

E-mail: shivali.chourasia@gmail.com

Highlights

• Effects of various parameters on the attrition of bed particles were studied in a RCFB.

• Attrition of sand particles was found to be significantly affected by operation time.

• Particles of size less than 300 μm were found to be elutriated with fluidizing air.

• Material loss was significant with higher superficial velocity, bed inventory and spacer height.

Abstract

We performed an experimental study to investigate the effects of various parameters on the attrition of bed material and its size distribution with increasing operation time in a recirculating fluidized bed (RCFB). The studied parameters included superficial velocity of fluidizing air, bed inventory, and spacing between the jet top and draft tube bottom (spacer height). The bed material was prepared from Indian Standard (IS) Grade I sand from sieves with a size range of 2.20–1.00 mm. Experiments were performed at ambient conditions, with the superficial air velocity ranging from 7.13–9.16 m/s, a bed inventory of 7–10 kg, spacing of 0.085 and 0.045 m between the jet top and draft tube bottom, and an operating time of 40 h. We investigated the influence of these parameters in terms of changes in the size distribution of particles, changes in the %-weight of particles of different size ranges, generation of particles with smaller diameters, the decrease of the downcomer bed height, variations in the coefficient of uniformity and coefficient of curvature, and material loss from entrainment of fines with increasing operation time. The mode of attrition was abrasion in all experiments. We found that with increasing operation time and other parameters (bed inventory, superficial air velocity, and spacer height) attrition of the bed material also increased. Generation and elutriation of fines were more pronounced at higher superficial air velocity, bed inventory, and spacer height.

Graphical abstract

Keywords

Attrition; Recirculating fluidized bed (RCFB); Fluidization; Elutriation; Fines

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