Particle suspension in (air-agitated) pachuca tanks

Abstract

Particle suspension is an important parameter in the design of an energy-efficient Pachuca tank. Unfortunately, very little attention has been focused on the suspension behavior of air-agitated Pachucas. In the present investigation, therefore, extensive experiments have been carried out in three laboratory-scale Pachuca tanks to examine the effect of design and operating parameters, as well as scale-up, on particle suspension. A mathematical model that combines the Bernoulli's equation and the theory of transport of particles in the horizontal flow of a liquid has been developed to predict the critical gas velocity for particle suspension in Pachuca tanks. Some important results, crucial to the design and scale-up of Pachuca tanks, have emerged. Full-center-column (FCC) Pachuca tanks with a draft tube-to-tank diameter ratio (D d /D t ) on the order of 0.1 are found to be energetically more efficient in suspending particles than free-air-lift (FAL) and stub-column (SC) Pachuca tanks. It is also observed that taller tanks require lower air flow rates for particle suspension than shallower tanks. Finally, it is explained why industrial Pachuca tanks operate at lower air velocities than laboratory-scale tanks.

The use of neural network to estimate mass transfer coefficient from the bottom of agitated vessel

“…Moreover, conical bottom vessels have the advantage of absence of stagnation point associated with sharp corners [11] and assure complete drainage of the solution and suspended matters. Of these tanks is the Pachucca tank that is widely used in hydrometallurgical processes [12,13].…”

Particle suspension in air-agitated pachuca tanks: Investigation of hysteresis and a novel split air injection technique

“…Details about the classification, resuspend the settled solids; its power rating, therefore, design, and operation of Pachuca tanks are available in the should conform with the critical air velocity required to literature. [1,2] As these tanks are operated with slurries congenerate suspension. However, hysteresis in particle suspentaining 50 to 60 wt pct solids, the principal objective in sion has not been adequately characterized.…”

“…[1,2] studies on hysteresis have been limited to bubble columns With the help of extensive experiments and mathematical only, which substantially differ from Pachuca tanks both in modeling. Roy et al [1] have clarified the effect of the design terms of dimensions and mode of operation. [1] and operating parameters of Pachuca tanks on the minimum…”

“…Roy et al [1] have clarified the effect of the design terms of dimensions and mode of operation. [1] and operating parameters of Pachuca tanks on the minimum…”

“…Partiin Pachuca tanks. In most investigations on bubble columns, cle suspension has been characterized with respect to both as well as in that of Hallett et al [3] on Pachuca tanks, particle maintaining [1] and generating [3,4] suspensions. Moreover, suspension has been characterized in terms of complete offboth definitions of critical air velocity have practical relebottom suspension.…”