Experimental and Modeling Investigation of Liquid-Induced Agglomeration in a Gas–Solid Fluidized Bed with Liquid Spray

Abstract

Particle agglomeration induced by liquid bridge force widely exists in industrial fluidization processes involving liquid spray. To understand the agglomeration mechanism, a cold-mode fluidized bed loaded with wax-coated graphite particles is constructed and heated by an electromagnetic induction method. In the experiments, the wet agglomerate mass is obtained online through the pressure drop measurement and the heat conservation relationship. Besides, an energy balance model is proposed based on the kinetic energy of rebounding of wet particles and the dissipation energy of liquid bridge to further study the evolution of liquid-induced agglomerates via a Monte Carlo method. The simulation and experimental results agree well and indicate that the agglomerate mass decreases with the particle exothermic rate and superficial gas velocity and increases with the liquid injection rate. This work provides an effective method for online characterization of wet agglomerates and is beneficial for the stable operation of industrial fluidized-bed reactors.

Polypropylene Composites Reinforced by Nonmetallic from Waste Printed Circuit Boards Using Spout-Fluid Bed Coating with PP Particles Enhance Fluidization

“…Under this condition, the growth mode of particles changed from agglomeration to layer growth. The modified particle size was reduced with the inhibition of agglomeration, which was conducive to the uniform coating of modified particles on the surface [ 31 ]. Therefore, the mechanical strength of the composites also increased.…”

Review of Research Related to Fluid Cokers

“…Agglomerate breakup, which reduces the coke yield and operating issues, is promoted when agglomerates flow through highly turbulent regions. Models have been developed to predict agglomerate breakup, which occurs when the shear force from a gas bubble flowing near an agglomerate is greater than the liquid bridge force that keeps the wet agglomerate together. , Gas mixing affects the removal of vapors from the bed and vapor-phase cracking. Solid mixing affects vaporization kinetics because hot solids must be brought to liquid-rich regions to provide heat for product vaporization; good solid mixing is required to mitigate the cooling effect of liquid vaporization. − If wet solids reach the stripping zone at the bottom of the reactor, valuable hydrocarbons may be lost to the cold coke return line (Figure ) and fouling of the stripper sheds (Figure ) is accelerated, which may lead to the premature shutdown of the coker. − …”

“…Models have been developed to predict agglomerate breakup, which occurs when the shear force from a gas bubble flowing near an agglomerate is greater than the liquid bridge force that keeps the wet agglomerate together. 50,51 Gas mixing affects the removal of vapors from the bed and vapor-phase cracking. Solid mixing affects vaporization kinetics because hot solids must be brought to liquid-rich regions to provide heat for product vaporization; good solid mixing is required to mitigate the cooling effect of liquid vaporization.…”

Effect of Liquid Addition on Gas‐Solid Fluidization

“…He et al [19] investigated the mineralogical characterization of various-sized bauxite samples using a dry-based fluidized-bed separator and obtained reasonable operating conditions for notably improved efficiency. Sun et al [20] designed a fluidized bed coupled with electromagnetic induction heating and studied the mass fraction of wet agglomerates. They showed that the agglomerate mass decreases with the particle exothermic rate and superficial gas velocity and increases with the liquid injection rate.…”

“…Sun et al. 20 designed a fluidized bed coupled with electromagnetic induction heating and studied the mass fraction of wet agglomerates. They showed that the agglomerate mass decreases with the particle exothermic rate and superficial gas velocity and increases with the liquid injection rate.…”