Comparison of two different ultrasound reactors for the treatment of cellulose fibers

Pamidi, Taraka Rama Krishna; Johansson, Örjan; Löfqvist, Torbjörn; Shankar, Vijay

doi:10.1016/j.ultsonch.2019.104841

Cited by 10 publications

(7 citation statements)

References 7 publications

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“…Disruption of Escherichia coli [25] , degradation of dichlorvos [26] , removal of pharmaceuticals from wastewater [27] , waste-activated sludge pretreatment [28] and effluent treatment [29] have also been proposed. Regarding the treatment of biomass using hydrodynamic cavitation, treatment of cellulose [30] , [31] , [32] , delignification of wheat straw [33] , pretreatment of lignocellulosic biomass [34] , pretreatment of rice bran for microbial fuel cells for electricity generation [35] , pretreatment of sugarcane bagasse [36] , biomass extraction [37] and energy harvesting with microscale hydrodynamic cavitation thermoelectric generation coupling [38] have been investigated. Pretreatments of biomass using hydrodynamic cavitation and ultrasonic cavitation were compared [34] .…”

Section: Introductionmentioning

confidence: 99%

Luminescence intensity of vortex cavitation in a Venturi tube changing with cavitation number

Soyama

2021

Ultrasonics Sonochemistry

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Section: Introductionmentioning

confidence: 99%

Luminescence intensity of vortex cavitation in a Venturi tube changing with cavitation number

Soyama

2021

Ultrasonics Sonochemistry

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“…For the Bingham model, different parameter settings were tested based on the literature [9,[28][29][30][31]. The final and best performing was the one used to compare the ODF model with the parameters a = 222, 000 Pa, b = 1.95, µ 0 = 100 Pa • s. The best performing parameter setting for the ODF model was the one where the standard deviation was computed with the slope 1.25 and D f was set to 1, i.e., setting R6 according to Table 1.…”

Section: Resultsmentioning

confidence: 99%

CFD Analysis of Turbulent Fibre Suspension Flow

Shankar

Lundberg

Pamidi

et al. 2020

Fluids

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A new model for turbulent fibre suspension flow is proposed by introducing a model for the fibre orientation distribution function (ODF). The coupling between suspended fibres and the fluid momentum is then introduced through the second and fourth order fibre orientation tensors, respectively. From the modelled ODF, a method to construct explicit expressions for the components of the orientation tensors as functions of the flow field is derived. The implementation of the method provides a fibre model that includes the anisotropic detail of the stresses introduced due to presence of the fibres, while being significantly cheaper than solving the transport of the ODF and computing the orientation tensors from numerical integration in each iteration. The model was validated and trimmed using experimental data from flow over a backwards facing step. The model was then further validated with experimental data from a turbulent fibre suspension channel flow. Simulations were also carried out using a Bingham viscoplastic fluid model for comparison. The ODF model and the Bingham model performed reasonably well for the turbulent flow areas, and the latter model showed to be slightly better given the parameter settings tested in the present study. The ODF model may have good potential, but more rigorous study is needed to fully evaluate the model.

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“… 72 The expected damage from pressure differences is an explosion rupture, differing from the dominant damage type observed ( Figures 4 , 6 and Supporting Information ). Rapid pressure changes may be the cause of fiber modification, 19 − 21 including local modifications of the open pores, i.e., pits, 73 but they are regarded of minor importance for fiber fibrillation by cavitation.…”

Section: Discussionmentioning

confidence: 99%

“…Hydrodynamic and acoustic cavitation are known and employed for the modification of cellulose fiber properties while preserving the fiber shape, that is, internal fibrillation, − and, especially acoustic cavitation, for the external fibrillation of cellulose fibers and the production of nanocellulose. ,− For that, cohesive forces between the fibrils need to be overcome by external stressing. Higher treatment intensity and exposure time increase the degree of fibrillation and benefit the development of the cellulose fibers to smaller sizes. , However, also the fibril length and cellulose crystallinity (i.e., the regions of the structured organization of the glucose polymer and its constituting glucose monomer) are decreasing, which is often regarded as quality degradation. ,, Cavitation, especially acoustic cavitation, is also employed to intensify chemical modification .…”

Section: Introductionmentioning

confidence: 99%

Cavitation Fibrillation of Cellulose Fiber

et al. 2022

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Cellulose fibrils are the structural backbone of plants and, if carefully liberated from biomass, a promising building block for a bio-based society. The mechanism of the mechanical release—fibrillation—is not yet understood, which hinders efficient production with the required reliable quality. One promising process for fine fibrillation and total fibrillation of cellulose is cavitation. In this study, we investigate the cavitation treatment of dissolving, enzymatically pretreated, and derivatized (TEMPO oxidized and carboxymethylated) cellulose fiber pulp by hydrodynamic and acoustic (i.e., sonication) cavitation. The derivatized fibers exhibited significant damage from the cavitation treatment, and sonication efficiently fibrillated the fibers into nanocellulose with an elementary fibril thickness. The breakage of cellulose fibers and fibrils depends on the number of cavitation treatment events. In assessing the damage to the fiber, we presume that microstreaming in the vicinity of imploding cavities breaks the fiber into fibrils, most likely by bending. A simple model showed the correlation between the fibrillation of the carboxymethylated cellulose (CMCe) fibers, the sonication power and time, and the relative size of the active zone below the sonication horn.

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Comparison of two different ultrasound reactors for the treatment of cellulose fibers

Cited by 10 publications

References 7 publications

Luminescence intensity of vortex cavitation in a Venturi tube changing with cavitation number

Luminescence intensity of vortex cavitation in a Venturi tube changing with cavitation number

CFD Analysis of Turbulent Fibre Suspension Flow

Cavitation Fibrillation of Cellulose Fiber

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