Study of material agglomeration during nozzle injection of multiviscosity liquid into a fluidized bed reactor by the electric conductance method--颗粒学报PARTICUOLOGY

Yang, N., Zhou, Y., & Qi, T. (2018). Study of material agglomeration during nozzle injection of multiviscosity liquid into a fluidized bed reactor by the electric conductance method. Particuology, 38, 174-184. https://doi.org/10.1016/j.partic.2017.04.014

Study of material agglomeration during nozzle injection of multiviscosity liquid into a fluidized bed reactor by the electric conductance method

Ning Yang ^a *, Yunlong Zhou ^a, Tianyu Qi ^b

a College of Energy Resource and Power Engineering, Northeast Dianli University, Jilin 132012, China
b Institute of Unclear and New Energy Technology, Tsinghua University, Beijing 100084, China

10.1016/j.partic.2017.04.014

Volume 38, June 2018, Pages 174-184

Received 8 October 2016, Revised 29 March 2017, Accepted 12 April 2017, Available online 12 October 2017, Version of Record 2 April 2018.

E-mail: yangning@nedu.edu.cn

Highlights

• Bed material agglomeration during injecting multi-viscosity liquid jets was studied.

• Water-sand system at room temperature was used to simulate the hot bitumen-coke system.

• Different agglomeration stages were identified in a fluidized bed based on conductance method.

Abstract

Fluidized bed agglomeration is an important and challenging problem for thermal cracking in fluid cokers. A low coker temperature can be problematic because the bitumen is injected into the fluidized bed with a different viscosity, resulting in formation of agglomerates of varying sizes, which slows the cracking reactions. In the present study, the bed material agglomeration process during nozzle injection of multiviscosity liquid was investigated in a fluidized bed operated at different mass ratios of the atomization gas to the liquid jets (GLR = 1%–3.5%) and gas velocities (3.9U_mf and 5.9U_mf) based on a conductance method using a water–sand system to simulate the hot bitumen–coke system at room temperature. During the tests of liquid-jet dispersion throughout the bed, different agglomeration stages are observed at both gas velocities. The critical amount of tert-butanol in the liquid jets that could lead to severe agglomeration of the bed materials (poor fluidization) at GLR = 1% is about 10 wt% at the low fluidizing gas velocity (3.9U_mf) and 18 wt% at the high gas velocity (5.9U_mf). This study provides a new approach for on-line monitoring of bed agglomeration during liquid injection to guarantee perfect contact between the atomized liquid and the bed particles.

Graphical abstract

Keywords

Material agglomeration; Nozzle; Multiviscosity; Fluidized bed reactor; Electric conductance

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