Volumenbezogene Stoffübergangskoeffizienten beim Strahldüsen‐Schlaufenreaktor

Warnecke, Hans‐Joachim; Geisendörfer, M.; HußMann, P.; Hempel, D. C.; Langemann, Horst

doi:10.1002/cite.330591011

Cited by 8 publications

(5 citation statements)

References 8 publications

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“…At power inputs of N /VR:s 8 kW m-3 kLa values of about 0.1 to 0.4 S-I are achieved and at those of 35 kW m-3-less economicalvalues of about 1.2 S-I. Figure 6 shows a satisfying agreement of the k,« values evaluated by the hydrazine method with those by the stationary physical method [7] in the same JLR.…”

Section: Resultssupporting

confidence: 54%

“…Its flow sheet is shown in Figure I the feed rate of hydrazine into the JLR equals the difference of the convective streams and the consumption rate (2) As the difference of the convective streams corresponds to the consumption rate in the circulation pipe (3) the feed rate of hydrazine is given by the sum of the consumption rates (4) The corresponding stationary oxygen mass balance shows that the oxygen transfer rate equals the sum of its consumption rates, too (5) Hence, as (6) the absorption rate of oxygen at steady state is given by the feed rate of hydrazine. Then under the admissible assumptions that there is 1. no enhancement 2. no accumulation of hydrazine 3. no gas-side resistance to mass transfer kLa results from nHy which has to be adjusted, the liquid volume V L and the liquid side oxygen concentration gradient !…”

Section: Introductionmentioning

confidence: 99%

“…(1) THEORY At recycle factors greater than 0.9 the continuously driven JLR can be treated as CSTR concerning the liquid phase as well as the gas phase [5]. Its flow sheet is shown in Figure I the feed rate of hydrazine into the JLR equals the difference of the convective streams and the consumption rate (2) As the difference of the convective streams corresponds to the consumption rate in the circulation pipe (3) the feed rate of hydrazine is given by the sum of the consumption rates (4) The corresponding stationary oxygen mass balance shows that the oxygen transfer rate equals the sum of its consumption rates, too (5) Hence, as (6) the absorption rate of oxygen at steady state is given by the feed rate of hydrazine.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Volumetric Mass Transfer Coefficents of Gas Liquid Jet Loop Reactors by Oxidation of Hydrazine

Warnecke

Hubmann

1989

Chemical Engineering Communications

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Oxidation of hydrazine in the presence of a homogeneous catalyst (CuTeSP) has been proved as a suitable reaction for the determination of volumetric mass transfer coefficients kLa of stirred tank reactors. This method is applied to a gas liquid jet loop reactor (JLR).At power inputs of N/VRs8kW/m3 kt.a values of about 0.1 and 0.4s-1 were achieved. The evaluated values agree well with those determined by a stationary physical method.

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Section: Resultssupporting

confidence: 54%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Volumetric Mass Transfer Coefficents of Gas Liquid Jet Loop Reactors by Oxidation of Hydrazine

Warnecke

Hubmann

1989

Chemical Engineering Communications

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“…The JZR is a representative industrial gas-liquid contact apparatus. A wide range of applications has been reported in chemical processes as well as in wastewater treatment [20,21]. The JZR provides a complex hydrodynamic structure with a downward adjusted two-phase nozzle (Fig.…”

Section: Reference Measurement Setups: Jet-zone Loopmentioning

confidence: 99%

Experimental Assessment of an Innovative Device to Mimic Bubble Swarm Turbulence

et al. 2017

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The local mass transfer of a bubble under swarm turbulence influence is the key to the performance of gas-liquid contactors. For measurements, optical accessibility is reduced due to an increased void fraction. The performance of a flexible grid of rigid particles to mimic the hydrodynamic conditions of bubble-induced swarm turbulence is assessed using spectral energy density distribution and an approach to connect the turbulent intensity to the according length scale of the flow. Despite the significant physical property differences to real bubbly flow the flexible grid is found to realistically mimic the swarm turbulence of a cocurrent bubble column. Hence, a single bubble approaching the proposed flexible grid experiences hydrodynamic conditions comparable to real bubble-induced turbulence.

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“…J et loop reactors are widely used in chemical and biological processes, in particular, in multi phase systems because of their high mass transfer performance (Warnecke et al, 1987) and their good macromixing behaviour (Harnby et al, 1992). One reason for the high mass transfer is the amount of energy, which is dissipated in these reactors.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the local specific energy dissipation rates in a jet‐zone loop reactor for halogenation of ketones

2010

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Within the framework of process intensification there is a growing demand for novel reactor technologies. For the improvement of halogenation of ketones a jet-zone loop reactor (JZR) is used, which leads to an enormous increase in yield and selectivity compared to stirred vessels (Kutschera et al., 2008). This JZR is a special jet loop reactor with high specific mass transfer performance and good macromixing behaviour. It is obvious that there is direct relation between the reaction and the hydrodynamics in the reactor. Despite several aspects of hydrodynamics in jet loop reactors have been investigated, the essential flow characteristics behind a two-component jet are not sufficiently understood. In these investigations, the flow field in the jet zone of the JZR was analysed by 2D particle image velocimetry (PIV) and the kinetic energy dissipation rate ε was determined from the spatial gradients of the fluctuating velocity.Dans le cadre de l'intensification des processus, on enregistre une demande grandissante pour de nouvelles technologies de réacteur. En vue de l'amélioration de l'halogénation des cétones, un réacteurà jet età boucle de circulation jet-zone (JZR) est utilisé, lequel produit une augmentatioń enorme du rendement et de la sélectivité en comparaison des réservoirs agités (Kutschera et al., 2008). Ce réacteur JZR est un réacteur spécialà jet età boucle de circulation avec haut rendement de transfert de masse spécifique et un bon comportement de macro-mélange. Il estévident qu'il existe une relation directe entre la réaction et leséléments hydrodynamiques présents dans le réacteur. En dépit du fait que plusieurs aspects de l'hydrodynamique des réacteursà jet età boucle de circulation ontétéétudiés, les caractéristiques essentielles de l'écoulement derrière un jet a deux composantes ne sont pas suffisamment bien comprises. Dans cesétudes, le champ d'écoulement dans la zone du jet du réacteur JZR aété analysé par vélocimétrie de dynamique des fluides en 2 dimensions (PIV) et le taux de dissipation de l'énergie cinétique ε aété déterminéà partir des gradients spatiaux de vélocité fluctuante.

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Volumenbezogene Stoffübergangskoeffizienten beim Strahldüsen‐Schlaufenreaktor

Cited by 8 publications

References 8 publications

Volumetric Mass Transfer Coefficents of Gas Liquid Jet Loop Reactors by Oxidation of Hydrazine

Volumetric Mass Transfer Coefficents of Gas Liquid Jet Loop Reactors by Oxidation of Hydrazine

Experimental Assessment of an Innovative Device to Mimic Bubble Swarm Turbulence

Investigation of the local specific energy dissipation rates in a jet‐zone loop reactor for halogenation of ketones

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