Mixing quality in low consistency fibre suspensions downstream of an in-line mechanical mixer measured by electrical resistance tomography

Yenjaichon, Wisarn; Grace, John R.; Lim, C. Jim; Kerekes, R. J.; Bennington, C. P. J.

doi:10.3183/npprj-2014-29-03-p392-400

“…Once the step change in conductivity reached to the steady-state conductivity value, the mixing index calculation was performed to study the conductivity distribution in 316 pixels of each tomography planes. The mixing index was calculated using the following equation (Alberini et al, 2014;Diggle, 2003;Reardon and O'Sullivan, 2004;Yenjaichon et al, 2012;Yenjaichon et al, 2014):…”

Section: Mixing Index Measurementsmentioning

confidence: 99%

“…Quantitatively, the distributive mixing quality was determined using the coefficient of variation (CoV) of the conductivity values in each ERT image, which is also known as the mixing index. The mixing index can be calculated using the below expression (Alberini et al, 2014;Diggle, 2003;Reardon and O'Sullivan, 2004;Yenjaichon et al, 2012;Yenjaichon et al, 2014):…”

Section: According Tomentioning

confidence: 99%

Using electrical resistance tomography (ERT) and computational fluid dynamics (CFD) to study the mixing of yield-pseudoplastic fluids in the SMX static mixer

Jegatheeswaran¹

2021

Preprint

0

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In this study, both electrical resistance tomography (ERT) and computational fluid dynamics (CFD) were employed to study the performance of the SMX static mixer in the mixing of a secondary fluid in a yield-pseudo plastic primary fluid. Using ERT, the effects of the primary fluid rheology, the primary fluid flow rate, and the secondary fluid type (Newtonian and non-Newtonian) were investigated. A CFD model was then developed for the fluid mixing in the SMX static mixer and was validated using the experimental pressure drop and the ERT mixing index measurements. Using the validated CFD flow model, the effects of the primary/secondary flow ratio and the secondary fluid viscosity on the mixing performance of the SMX static mixer were analyzed. The results from this study revealed that the SMX static mixer was effective for the mixing of highly viscous fluids especially at a lower primary/secondary flow ratio.

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“…Once the step change in conductivity reached to the steady-state conductivity value, the mixing index calculation was performed to study the conductivity distribution in 316 pixels of each tomography planes. The mixing index was calculated using the following equation (Alberini et al, 2014;Diggle, 2003;Reardon and O'Sullivan, 2004;Yenjaichon et al, 2012;Yenjaichon et al, 2014):…”

Section: Mixing Index Measurementsmentioning

confidence: 99%

“…Quantitatively, the distributive mixing quality was determined using the coefficient of variation (CoV) of the conductivity values in each ERT image, which is also known as the mixing index. The mixing index can be calculated using the below expression (Alberini et al, 2014;Diggle, 2003;Reardon and O'Sullivan, 2004;Yenjaichon et al, 2012;Yenjaichon et al, 2014):…”

Section: According Tomentioning

confidence: 99%

Using electrical resistance tomography (ERT) and computational fluid dynamics (CFD) to study the mixing of yield-pseudoplastic fluids in the SMX static mixer

Jegatheeswaran¹

2021

Preprint

0

View full text Add to dashboard Cite

In this study, both electrical resistance tomography (ERT) and computational fluid dynamics (CFD) were employed to study the performance of the SMX static mixer in the mixing of a secondary fluid in a yield-pseudo plastic primary fluid. Using ERT, the effects of the primary fluid rheology, the primary fluid flow rate, and the secondary fluid type (Newtonian and non-Newtonian) were investigated. A CFD model was then developed for the fluid mixing in the SMX static mixer and was validated using the experimental pressure drop and the ERT mixing index measurements. Using the validated CFD flow model, the effects of the primary/secondary flow ratio and the secondary fluid viscosity on the mixing performance of the SMX static mixer were analyzed. The results from this study revealed that the SMX static mixer was effective for the mixing of highly viscous fluids especially at a lower primary/secondary flow ratio.

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“…Since the mixing vessel is a closed system, ERT is implemented as a tool to investigate the mixing phenomena. ERT has also been utilised to study the mixing behaviour of gas-liquid-solid systems, fibre suspensions, pulp mixing, polymer particles mixing and many more [19][20][21][22][23][24][25]. But less has been written about the use of ERT to study the gas-liquid mixing phenomena [26].…”

Section: Introductionmentioning

confidence: 99%

Study of gas–liquid mixing in stirred vessel using electrical resistance tomography

Sher

¹

,

Sajid

²

,

Tokay

³

et al. 2016

Asia-Pacific J Chem Eng

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Hamad (2016) Study of gas-liquid mixing in stirred vessel using electrical resistance tomography. Asia-Pacific Journal of Chemical Engineering . ISSN 1932ISSN -2143 Access from the University of Nottingham repository: http://eprints.nottingham.ac.uk/35359/1/Manuscript%20ERT.pdf Copyright and reuse:The Nottingham ePrints service makes this work by researchers of the University of Nottingham available open access under the following conditions. This article is made available under the University of Nottingham End User licence and may be reused according to the conditions of the licence. For more details see: http://eprints.nottingham.ac.uk/end_user_agreement.pdf A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription. AbstractThis study presents a full operation and optimisation of a mixing unit; an innovative approach is developed to address the behaviour of gas-liquid mixing by using Electrical Resistance Tomography (ERT). The validity of the method is investigated by developing the tomographic images using different numbers of baffles in a mixing unit. This technique provided clear visual evidence of better mixing that took place inside the gasliquid system and the effect of a different number of baffles on mixing characteristics. For optimum gas flow rate (m 3 /s) and power input (kW), the oxygen absorption rate in water was measured. Dynamic gassingout method was applied for five different gas flow rates and four different power inputs to find out mass transfer coefficient (KLa). The rest of the experiments with one up to four baffles were carried out at these optimum values of power input (2.0 kW) and gas flow rate (8.5×10 -4 m 3 /s). The experimental results and tomography visualisations showed that the gasliquid mixing with standard baffling provided near the optimal process performance and good mechanical stability, as higher mass transfer rates were obtained using a greater number of baffles. 2 mixing was remarkably reduced in the case of four baffles as compared to without any baffle. The process economics study showed that the increased cost of baffles installation accounts for less cost of energy input for agitation. The process economics have also revealed that the optimum numbers of baffles are four in the present mixing unit and the use of an optimum number of baffles reduced the energy input cost by 54%.

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Mixing quality in low consistency fibre suspensions downstream of an in-line mechanical mixer measured by electrical resistance tomography

Cited by 5 publications

References 0 publications

Using electrical resistance tomography (ERT) and computational fluid dynamics (CFD) to study the mixing of yield-pseudoplastic fluids in the SMX static mixer

Using electrical resistance tomography (ERT) and computational fluid dynamics (CFD) to study the mixing of yield-pseudoplastic fluids in the SMX static mixer

Using electrical resistance tomography (ERT) and computational fluid dynamics (CFD) to study the mixing of yield-pseudoplastic fluids in the SMX static mixer

Study of gas–liquid mixing in stirred vessel using electrical resistance tomography

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