Dynamics of fines deposition in an alternating semifluidized bed

Abstract

in Wiley InterScience (www.interscience.wiley.com).A semifluidized bed was proposed to allay bed plugging during the filtration of fines-hydrocarbon suspensions. Mitigation of plugging was allowed by alternating semifluidization during capture with unconstrained fluidization for removal of deposits. Solids holdup conditions were established to prevent deposition in the fluidization section. The cyclic parameters were varied to allow efficient removal of deposits during washing. Analysis with a filtration model accounting for solids detachment in the fixed bed section revealed that the fluidization section favored growth of aggregate size entering the fixed bed. Analysis of the split ratios between fixed and fluidized bed heights revealed that the shallowest fluidization sections delayed deposition in the fixed bed. In cyclic operation, reversibility of the semifluidized bed was best recovered via gas injection during the washing stages. However, the filtration times in successive cycles shortened with increasing washing times but lengthened with increasing the washing superficial suspension velocity.Dotted lines/empty symbols shows simulations by depth filtration model Eqs. 7-14. Figure 8. Effect of split ratio on overall capture efficiency and global filter coefficient vs. specific deposit (R 5 1; H F 5 0.25 m), (R 5 2; H F 5 0.34 m), (R 5 3; H F 5 0.34 m), (R 5 '; H F 5 0.42 m), U Lsf 5 0.042 m/s.

Hydrodynamics of regular particles in a liquid–solid semi-fluidized bed

“…14 shows the comparison of the values of (h − h s )/(h − h pa ) predicted from Eqs. (14)- (17) with the experimental ones. Almost all values are within 15% of the experimental ones in case of these equations.…”

“…Subsequently a good number of research articles relating to various applications of the semi-fluidized bed system have been reported in literature [3][4][5][6][7][8][9][10][11][12][13][14]. Additionally, fairly a good number of patents claimed since the year 1958, relating to the best possible applications of the semi-fluidized bed in many industrial processes are listed in SciFinder Scholar database like the recent one by Liu et al [15].…”

The Impact of Process Parameters on the Deposition of Fines Present in Bitumen-Derived Gas Oil on Hydrotreating Catalyst

“…Several studies reported that the pressure drop in a hydrotreater increased with the concentration of the fine particles. 34…”

“…Also, higher pressure that is statistically shown to decelerate the bed deposition in the case of feed with high fines concentration might be compensating the pressure drop in the reactor due to catalyst pore plugging. Several studies reported that the pressure drop in a hydrotreater increased with the concentration of the fine particles …”

Phase Holdups in Three-Phase Semifluidized Beds and the Generalized Bubble Wake Model

“…Some of the early semifluidized bed applications concerned biological systems in which the fluidized layer, exhibiting the highest backmixing, carries the main load of biological reaction, whereas the top packed bed acts as a polishing section. Recently, Dehkissia et al studied the filtration behavior in an alternating bed, switching between semifluidization and fluidization for oil sand application.…”