Heat and water transfer in a rotating drum containing solid substrate particles

Schutyser, M.A.I.; Weber, F.J.; Briels, Willem J.; Rinzema, A.; Boom, R.M.

doi:10.1002/bit.10601

Cited by 21 publications

(9 citation statements)

References 19 publications

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“…Gas volume within solid substrate particles inside bioreactors represents the void fraction. The void space depends on the solid substrate particle characteristics and also moisture content [131,132]. Moisture content should be optimum; not too high or too low.…”

Section: Bioreactor Type Features/problemsmentioning

confidence: 99%

Design Aspects of Solid State Fermentation as Applied to Microbial Bioprocessing

Webb¹

2017

JABB

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Solid state fermentation (SSF) refers to the microbial fermentation, which takes place in the absence or near absence of free water, thus being close to the natural environment to which the selected micro organisms, especially fungi, are naturally adapted. SSF has been used in the world for a long time. This technology is commonly known in the East, for traditional manufacture of fermented foods, and in the west, for mould-ripened cheese. It can be defined as a system, in which the growth of selected microorganism(s) occurs on solid materials with low moisture contents and has been identified as a potentially important methodology and technique in biotechnology. Nowadays, SSF is an economically viable, practically acceptable technology for large-scale bioconversion and biodegradation processes. Development of sustainable SSF and bioprocess technology is an emerging, multidisciplinary field with possible application to the production of enzymes, chemicals, bioethanol and pharmaceuticals. SSF offers many advantages over conventional submerged fermentation (SMF) such as, simple and inexpensive substrates, elimination of the need for solubilisation of nutrient from within solid substrates, elimination of the need for rigorous control of many parameters during fermentation, product yields are mostly higher, lower energy requirements, produce less waste water, no foam generation and relatively easy recovery of end products. SSF provides flexibility in terms of the raw materials to be used and their capability to produce various value-added products. Keywords:

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Section: Bioreactor Type Features/problemsmentioning

confidence: 99%

Design Aspects of Solid State Fermentation as Applied to Microbial Bioprocessing

Webb¹

2017

JABB

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“…During SSF in a helicalblade mixer, micro-mixing is needed to entirely remove spatial gradients in, for example, temperature. If the mixing period applied is too short, regions with higher temperatures may persist, which may negatively affect the fermentation (Schutyser et al, 2003).…”

Section: Predicted Entropy Of Mixingmentioning

confidence: 99%

Numerical simulation and PEPT measurements of a 3D conical helical‐blade mixer: A high potential solids mixer for solid‐state fermentation

Schutyser

Briels

Rinzema

et al. 2003

Biotech & Bioengineering

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Helical-blade solids mixers have a large potential as bioreactors for solid-state fermentation (SSF). Fundamental knowledge of the flow and mixing behavior is required for robust operation of these mixers. In this study predictions of a discrete particle model were compared to experiments with colored wheat grain particles and positron emission particle tracking (PEPT) measurements. In the discrete particle model individual movements of particles were calculated from interaction forces. It was concluded that the predicted overall flow behavior matched well with the PEPT measurements. Differences between the model predictions and the experiments with wheat grains were found to be due to the assumption that substrate particles were spherical, which was in the model. Model simulations and experiments with spherical green peas confirmed this. The mixing in the helical-blade mixer could be attributed to (1) the transport of particles up and down in the interior of the mixer, and (2) dispersion or micro-mixing of particles in the top region of the mixer. It appeared that the mixing rate scaled linearly with the rotation rate of the blade, although the average particle velocity did not scale proportionally. It may be that the flow behavior changes as a function of the rotation rate (e.g., changing thickness of the top region); further study is required to confirm this. To increase the mixing performance of the mixer, a larger blade or a change in the shape of the mixer (larger top surface/volume ratio) is recommended.

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“…The two-phase model presented in this article consists of two parallel models; the discrete particle and the continuum model of the gas phase. During earlier work the continuum model was not required, because we did not consider the gas flow and related phenomena, such as heat and moisture exchange between the solid and the gas phase (Schutyser et al, 2003b). However, because the main mechanism for heat removal during SSF is evaporative cooling, we implemented an additional model for the gas flow through the substrate bed.…”

Section: Theorymentioning

confidence: 99%

“…The temperature of the solid substrate particle changes among others due to the conductive heat transfer through the contact points between the particle and its neighbors or the drum wall (Schutyser et al, 2003b). The change in heat, dQ i cond dt ;in particle i due to conduction depends on the number of contacts with its neighbors (n c ) and contact with the wall of the drum:…”

Section: Balances For the Solid Phasementioning

confidence: 99%

Combined discrete particle and continuum model predicting solid‐state fermentation in a drum fermentor

Schutyser

Briels

Boom

et al. 2004

Biotech & Bioengineering

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The development of mathematical models facilitates industrial (large-scale) application of solid-state fermentation (SSF). In this study, a two-phase model of a drum fermentor is developed that consists of a discrete particle model (solid phase) and a continuum model (gas phase). The continuum model describes the distribution of air in the bed injected via an aeration pipe. The discrete particle model describes the solid phase. In previous work, mixing during SSF was predicted with the discrete particle model, although mixing simulations were not carried out in the current work. Heat and mass transfer between the two phases and biomass growth were implemented in the two-phase model. Validation experiments were conducted in a 28-dm3 drum fermentor. In this fermentor, sufficient aeration was provided to control the temperatures near the optimum value for growth during the first 45-50 hours. Several simulations were also conducted for different fermentor scales. Forced aeration via a single pipe in the drum fermentors did not provide homogeneous cooling in the substrate bed. Due to large temperature gradients, biomass yield decreased severely with increasing size of the fermentor. Improvement of air distribution would be required to avoid the need for frequent mixing events, during which growth is hampered. From these results, it was concluded that the two-phase model developed is a powerful tool to investigate design and scale-up of aerated (mixed) SSF fermentors.

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Heat and water transfer in a rotating drum containing solid substrate particles

Cited by 21 publications

References 19 publications

Design Aspects of Solid State Fermentation as Applied to Microbial Bioprocessing

Design Aspects of Solid State Fermentation as Applied to Microbial Bioprocessing

Numerical simulation and PEPT measurements of a 3D conical helical‐blade mixer: A high potential solids mixer for solid‐state fermentation

Combined discrete particle and continuum model predicting solid‐state fermentation in a drum fermentor

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