Flow Regime Transition in a Trickle Bed Reactor

Bansal, Ajay; Wanchoo, R. K.; Sharma, Sanjeev

doi:10.1080/009864490522597

Cited by 20 publications

(24 citation statements)

References 23 publications

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“…In Figure 14, the experimental points of present study are drawn using correlation proposed by [3,15,24,25]. Here worthy to notice that the present trends observed for air-aqueous 15 ppm SLS shows a good accordance with foaming TBR studies of [3,15].…”

Section: Resultssupporting

confidence: 69%

“…Experimental points for change in regime transition boundary observed for present study drawn over regime coordinates proposed by Bansal[3,15,24].…”

mentioning

confidence: 96%

“…Estimation of surface tension influences on TBR is very complex to explain but Larachi et al [13] proposed an outstanding database based on a number of literature studies. Further, the effect of viscosity and surface tension on polymeric based polyacrylamide (PAA), carboxymethyl cellulose (CMC) and polyethylene glycol (PEG) over different catalyst sizes has been appreciably described by Bansal et al [3,15,24,25]. Further, the effect of viscosity and surface tension on polymeric based polyacrylamide (PAA), carboxymethyl cellulose (CMC) and polyethylene glycol (PEG) over different catalyst sizes has been appreciably described by Bansal et al [3,15,24,25].…”

mentioning

confidence: 99%

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Trickle/pulse flow regime transition in downflow packed tower involving foaming liquids

Sodhi¹

2012

CI&CEQ

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The most of past studies in foaming trickle bed reactors aimed at the improvement of efficiency and operational parameters leads to high economic advantages. Conventionally most of the industries rely on frequently used gas continuous flow (GCF) where operational output is satisfactory but not yields efficiently as in pulsing flow (PF) and foaming pulsing flow (FPF). Hydrodynamic characteristics like regime transitions are significantly influenced by foaming nature of liquid as well as gas and liquid flow rates. This study’s aim was to demonstrate experimentally the effects of liquid flow rate, gas flow rates and liquid surface tension on regime transition. These parameters were analyzed for the air-aqueous Sodium Lauryl Sulphate and air-water systems. More than 240 experiments were done to obtain the transition boundary for trickle flow (GCF) to foaming pulsing flow (PF/FPF) by use excessive foaming 15-60 ppm surfactant compositions. The trickle to pulse flow transition appeared at lower gas and liquid flow rates with decrease in liquid surface tension. All experimental data had been collected and drawn in the form of four different transitional plots which are compared and drawn by using flow coordinates proposed by different researchers. A prominent decrease in dynamic liquid saturation was observed especially during regime transitional change. The reactor two phase pressure evident a sharp rise to verify the regime transition shift from GCF to PF/FPF. Present study reveals, the regime transition boundary significantly influenced by any change in hydrodynamic as well as physiochemical properties including surface tension

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Section: Resultssupporting

confidence: 69%

“…Experimental points for change in regime transition boundary observed for present study drawn over regime coordinates proposed by Bansal[3,15,24].…”

mentioning

confidence: 96%

mentioning

confidence: 99%

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Trickle/pulse flow regime transition in downflow packed tower involving foaming liquids

Sodhi¹

2012

CI&CEQ

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“…The shear-dependent viscosity (μ a ) was based on the wall shear rate (γ), as defined by Tiu et al 12 and Bansal et al 40 and expressed as…”

Section: Experimental Section 21 Preparation and Characterization Omentioning

confidence: 99%

Creeping Flow of Viscoelastic Fluid through a Packed Bed

Sobti

Wanchoo

2014

Ind. Eng. Chem. Res.

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Experimental results on investigation of elastic effects in creeping flow of viscoelastic fluids through a packed bed of spherical particles are presented. A simple form of the corrective Weissenberg number (We) function is proposed to extend the use of the Ergun equation, applicable to fixed bed flow of purely viscous fluids, for the prediction of friction factor in creeping flow of viscoelastic fluids. In order to quantify the effect of fluid elasticity on frictional pressure drop, aqueous solutions of polyacrylamide in the concentration range of 0.25%−0.6% (wt/vol) were used as test fluids and an extensive pressure drop-flow rate data were generated. Friction factor or pressure drop exhibited asymptotic behavior with variation in We, depicting the onset of viscoelastic effects at critical We values with a magnitude of 0.1 and the dominance of elastic effects over inertial effects up to We = 1.1. The percentage drag enhancement, as a function of fluid relaxation time, in the applicable range of We, is also reported. The proposed correlation will be useful in the field of enhanced oil recovery.

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“…Improvements in TBR effectiveness and utilisation based on fundamental understanding can both reduce operation costs and increase process sustainability while meeting increasingly stringent environmental regulations (Bansal et al, 2005; Maiti and Nigam, 2007). The prospect of technological improvements continues to drive researchers and developers to enhance knowledge of TBRs and improve the understanding of the physicochemical phenomena involved in TBR operation.…”

Section: Introductionmentioning

confidence: 99%

Modelling and simulation of trickle‐bed reactors using computational fluid dynamics: A state‐of‐the‐art review

2011

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Trickle-bed reactors (TBRs), which accommodate the flow of gas and liquid phases through packed beds of catalysts, host a variety of gas-liquid-solid catalytic reactions, particularly in the petroleum/petrochemical industry. The multiphase flow hydrodynamics in TBRs are complex and directly affect the overall reactor performance in terms of reactant conversion and product yield and selectivity. Non-ideal flow behaviours, such as flow maldistribution, channelling or partial catalyst wetting may significantly reduce the effectiveness of the reactor. However, conventional TBR modelling approaches cannot properly account for these non-ideal behaviours owing to the complex coupling between fluid dynamics and chemical kinetics. Recent advances in the application of computational fluid dynamics (CFD) to three-phase TBR systems have shown promise of achieving a deeper understanding of the interactions between multiphase fluid dynamics and chemical reactions. This study is intended to give a state-of-the-art overview of the progress achieved in the field of CFD simulation of TBRs over the past two decades. The fundamental modelling framework of multiphase flow in TBRs, advances in important constitutive models, and the application of CFD models are discussed in detail. Directions for future research are suggested.RÉSUMÉ Les lits fixes arrosésà co-courant descendant de gaz et de liquide sont le siège d'innombrables processus catalytiques triphasiques, en particulier dans le domaine du raffinage pétrolier et de la pétrochimie. Les caractères polyphasique et non-idéal de leur hydrodynamique ont des répercussions importantes sur la conversion chimique, la productivité et la sélectivité. Ceci se traduit par l'entremise de la maldistribution des fluides, le mouillage partiel du catalyseur ou desécoulements préférentiels qui peuventêtre déterminants en ce qui a traità l'efficacité du réacteur. La mise enéquation rigoureuse de ces non-idéalités et des couplages réaction-hydrodynamique a longtemps résisté aux approches de conceptualisation dites « conventionnelles ». Cette revue de synthèse s'attarde par conséquentà discuter les récentes avancées dans l'utilisation de la mécanique des fluides numérique comme outil «émergent et non-conventionnel » de description quantitative et fine desécoulements et des réactions catalytiques, et de leur interaction au sein de ces réacteurs. Spécifiquement, nous discuterons de la pertinence des différentes approches multi-fluides mises en oeuvre, des relations constitutives développées et de l'utilisation de la mécanique des fluides numérique pour des applications pratiques des lits fixes arrosés. Nous suggérerons en guise d'épilogue de nouvelles directions de recherche dans ce domaine.Mots clés: Lit fixe arrosé, mécanique des fluides numérique, hydrodynamique polyphasique,équations constitutives tive amination, liquid-phase oxidation, etc.). TBRs are also used for the catalytic abatement of aqueous biocidal compounds in *

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Flow Regime Transition in a Trickle Bed Reactor

Cited by 20 publications

References 23 publications

Trickle/pulse flow regime transition in downflow packed tower involving foaming liquids

Trickle/pulse flow regime transition in downflow packed tower involving foaming liquids

Creeping Flow of Viscoelastic Fluid through a Packed Bed

Modelling and simulation of trickle‐bed reactors using computational fluid dynamics: A state‐of‐the‐art review

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