Einfluss der Rührwerksposition auf den Mischprozess in Biogasanlagen anhand eines Paddelrührwerks

Annas, Sven; Elfering, Michael; Volbert, Nico; Jantzen, Hans-Arno; Scholz, Jürgen; Janoske, Uwe

doi:10.1002/cite.201800116

Cited by 4 publications

(2 citation statements)

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“…In this work, by varying the fluid viscosity and the impeller speed, a wide set of fluid flow conditions ranging from the laminar to the turbulent regime have been investigated. The fluid viscosity was varied adopting aqueous solutions of carboxy-methylcellulose (CMC) polymer of different concentrations, which exhibit a pseudo-plastic behavior, as the fluids typically treated in biogas production digesters . Considering the impeller speed adopted in the industrial operations, which was equal to 12.5 rpm, the constant power consumption scale-down criterion based on the power number in the turbulent regime resulted in the impeller speed, N , of 133 rpm in the lab scale.…”

Section: Methodsmentioning

confidence: 99%

Power Consumption and Fluid Mixing in a Scale-Down Geometry of a Stirred Digester for Biogas Production

et al. 2023

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A unconventional stirred tank of geometry typically adopted for the production of biogas is experimentally investigated with pseudo-plastic model fluids. The apparent viscosities of the fluids, based on the Metzner–Otto method, are in the range of 39–264 mPa·s, resulting in a range of rotational Reynolds number equal to 17–648. The power consumption of the three top-entering agitators is measured by a strain gauge technique, and the power number curve is obtained in the full range of flow regimes, going from laminar to fully turbulent conditions. The flow field measured by particle image velocimetry allows us to observe the fluid circulation patterns and their variations in different operative conditions. The measurements reveal relatively low axial and radial velocities, especially toward the bottom of the tank, that may hinder solid feedstock suspension and subsequent biogas production. Significant changes in the flow patterns are observed with small variations in the impeller speed and the mixture viscosity. The homogenization dynamics of a tracer obtained by planar laser-induced fluorescence leads us to estimate the dimensionless mixing time, a trend similar to that observed for conventional stirred vessel geometries. The detailed fluid dynamics information collected by a combination of different techniques can contribute to optimize the energy requirement and to avoid failure of the biogas production due to poor fluid mixing.

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Section: Methodsmentioning

confidence: 99%

Power Consumption and Fluid Mixing in a Scale-Down Geometry of a Stirred Digester for Biogas Production

et al. 2023

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“…A continuous or intermittent operation is possible. Consequently, many combinations of configurations are possible and each selection results from conditions of optimization of the four main above listed objectives .…”

Section: Introductionmentioning

confidence: 99%

Numeric Simulation‐Based Analysis of the Mixing Process in Anaerobic Digesters of Biogas Plants

2020

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Stirring systems with two rotational three-bladed propellers were analyzed using computational fluid dynamics. The propellers are located at three heights and seven angles in a tank with 9 m radius. The fluid was characterized by non-Newtonian rheology and simulated by applying the k-e turbulence model and the standard k-w model. Reynolds numbers were estimated. High fluid speeds were obtained with the propellers located at a height of 2 m and oriented at 90°with respect to the tank radius. In the top regions of the tank, the fluid velocity was generally less intense and less affected by the angle setting. The configurations identified as good mixing systems showed power consumptions broadly distributed around 30 kW.

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Design, Implementation, and Evaluation of a Real Time Localization System for the Optimization of Agitation Processes

Heller

Horsthemke

Glösekötter

2023

Analysis, Estimations, and Applications of Embedded Systems

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Einfluss der Rührwerksposition auf den Mischprozess in Biogasanlagen anhand eines Paddelrührwerks

Cited by 4 publications

References 38 publications

Power Consumption and Fluid Mixing in a Scale-Down Geometry of a Stirred Digester for Biogas Production

Power Consumption and Fluid Mixing in a Scale-Down Geometry of a Stirred Digester for Biogas Production

Numeric Simulation‐Based Analysis of the Mixing Process in Anaerobic Digesters of Biogas Plants

Design, Implementation, and Evaluation of a Real Time Localization System for the Optimization of Agitation Processes

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