Power consumption and gas–liquid dispersion in turbulently agitated vessels with vertical dual-array tubular coil baffles

Wan, Xun; Takahata, Yasuyuki; Takahashi, Koji

doi:10.1515/chempap-2015-0221

Cited by 5 publications

(5 citation statements)

References 2 publications

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“…N P values of HB and 4WHd in the systems equipped with six groups of coil baffles are 2.36 and 1.36, respectively. This is in line with the results of previous work, [15] in which the standard of four planar baffles was similarly used as a reference and was considered to provide full baffling. The coil baffles could provide 95.2-94.4 % of the degree of baffling of the planar design.…”

Section: Power Measurement Under Unaerated Conditionssupporting

confidence: 89%

“…In a previous study, [15] we proved that the baffle coefficient of six groups of coil baffles (K B ¼ 0.12) is lower than that of the planar baffles (K B ¼ 0.25). However, differing from the macro-flow produced by the Rushton impeller, the macro-flows generated by HB and 4WHd are mainly radial or axial, and the tangential flow in these systems is very weak.…”

Section: Power Measurement Under Unaerated Conditionsmentioning

confidence: 70%

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Power consumption, gas holdup, and mass‐transfer coefficient of triple‐impeller configurations in a stirred vessel with vertical tubular coils

2016

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Three kinds of impeller combinations (3 × 4WHd, HB + 2 × 4WHd, 2 × HB + 4WHd) were used to investigate the effects of coil baffles on system power consumption, gas holdup, and mass transfer coefficient. The experiments were performed in a dish‐bottomed vessel with a diameter of 0.29 m. Results of the power consumption experiments show that at the same rotation speed and an increasing rate of gas flow, the power consumptions of 3 × 4WHd and 2 × HB + 4WHd with coil baffles are almost the same as that of a system with four planar baffles, but there is a clear power draw for the HB + 2 × 4WHd combination. At rotational speeds of 250–350 rpm, the largest power draws for the 2 × HB + 4WHd, HB + 2 × 4WHd, and 3 × 4WHd impeller combinations equipped with coil baffles are 27, 25, and 15 %, respectively. The gas holdup experiment shows that with installation of coil baffles in the vessel, axial and radial impeller combinations can achieve gas dispersion identical to that attained with planar baffles. At the same power input and superficial gas rate over a wide range of gas velocities, the kLa values of the coil baffles for the 3 × 4WHd and 2 × HB + 4WHd combinations are almost identical to those of a conventional system with four baffles. However, in the HB + 2 × 4WHd system, kLa values of the coil baffles are 15 % higher than for planar baffles at low gas velocities and 30 % higher at high superficial gas rates. Finally, all data from the experiments on gas holdup and kLa values may be correlated through the equations ϵ=α(Pg/V)β(Vs)γ and KL a=K1(PG/V)K2(VS)K3.

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Section: Power Measurement Under Unaerated Conditionssupporting

confidence: 89%

Section: Power Measurement Under Unaerated Conditionsmentioning

confidence: 70%

Power consumption, gas holdup, and mass‐transfer coefficient of triple‐impeller configurations in a stirred vessel with vertical tubular coils

2016

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“…• geometric parameters -vessel and impeller diameter, height of the liquid, impeller type, number of impellers etc. (Busciglio et al, 2013;Cooke and Heggs, 2005;Cudak, 2011Cudak, , 2014Niranjan, 1999, 2002;Major and Karcz, 2011;Major and Radecki, 2018;Moucha et al, 2003;Mueller and Dudukovic, 2010;Nocentini et al, 1993;Petricek et al, 2018, Pinelli et al, 2003Takriff et al, 2000;Wan et al, 2016;Vasconcelos et al, 2000;Xie et al, 2014;Yawalkar et al, 2002a),…”

Section: Introductionmentioning

confidence: 99%

“…The impeller type as well as its selection constitute the main criterion for maintaining the appropriate hydrodynamic status in the vessel in a two-phase system (Gogate et al, 2000). The Rushton turbine impeller is the most common impeller type used in the research on two-phase gas-liquid systems, as it ensures very good gas dispersion and thus good gas flow rate through the vessel (Busciglio et al, 2013;Mueller and Dudukovic, 2010;Nocentini et al,1993;Paglianti et al, 2000;Wan et al, 2016). The disadvantage of this impeller is its high energy consumption.…”

Section: Introductionmentioning

confidence: 99%

Chemical and Process Engineering

Cudak

2020

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The aim of the research presented in this paper was to determine the effect of vessel scale on gas holdup in gas-liquid systems. The agitated vessel with internal diameters of T = 0.288 m and T = 0.634 m was filled with a liquid up to the height H = T. For the purpose of measurements, two high-speed impellers were used: Rushton turbine impeller (RT) or A 315 impeller. Within the study, the following parameters were altered: superficial gas velocity, impeller speed, impeller type and concentration of aqueous sucrose solution. In addition, influence of the vessel scale on gas hold-up value was analysed. Experimental results were mathematically described. Equations ( 5)-( 7) do not have equivalents in the literature.

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“…Gas hold-up and power consumption for the gas–Newtonian liquid system produced in the agitated vessel with tubular baffles were investigated by Major-Godlewska and Karcz (2003, 2011), as well as by Wan et al (2016). Major-Godlewska and Karcz (2012) also experimentally studied process characteristics for the three phase gas–solid–Newtonian liquid system.…”

Section: Introductionmentioning

confidence: 99%

An effect of the tubular baffles configuration in an agitated vessel with a high-speed impeller on the power consumption

Major-Godlewska

Karcz

2018

Chem. Pap.

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The results of the power consumption for an agitated vessel equipped with vertical tubular baffles and high-speed impeller are presented in the paper. Aqueous solutions of CMC were agitated within transitional range of the non-Newtonian liquid flow in the agitated vessel of inner diameter equal to 0.6 m. Eight different types of the impellers were tested: Rushton or Smith turbines, turbine with straight blades, pitched blade turbines and propeller. The J tubular baffles of outer diameter B were located in the position e from the vessel wall. Different configurations of baffles, arranged around the vessel circumference singularly or blocked in the modules, were considered in the study. In total, 180 different tubular baffles–impeller systems were tested. The measurements of the torque were conducted by means of the strain gauges method. Based on the power characteristics obtained for each impeller type, the effect of the geometrical parameters of the vertical tubular baffles on the power number was determined and discussed. The results show that geometry of the tubular baffles mostly affects the power number for the system with radial flow Rushton turbine. Moreover, power numbers decrease with the increase of the clearance between baffle and vessel wall for the systems, in which the radially axial circulation of the liquid is promoted. The dependences of the power number on the geometrical parameters of the vertical tubular baffles arranged singularly around the vessel circumference were described by means of the Eqs. (5)–(16). These equations can be useful in the project computations.

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Power consumption and gas–liquid dispersion in turbulently agitated vessels with vertical dual-array tubular coil baffles

Cited by 5 publications

References 2 publications

Power consumption, gas holdup, and mass‐transfer coefficient of triple‐impeller configurations in a stirred vessel with vertical tubular coils

Power consumption, gas holdup, and mass‐transfer coefficient of triple‐impeller configurations in a stirred vessel with vertical tubular coils

Chemical and Process Engineering

An effect of the tubular baffles configuration in an agitated vessel with a high-speed impeller on the power consumption

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