The Influence of Temperature on Rheological Parameters and Energy Efficiency of Digestate in a Fermenter of an Agricultural Biogas Plant

Maciej Filip Gruszczyński, Tomasz Kałuża (), Wojciech Czekała, Paweł Zawadzki, Jakub Mazurkiewicz, Radosław Matz, Maciej Pawlak, Paweł Jarzembowski, Farokh Sahraei Nezhad and Jacek Dach
Additional contact information
Maciej Filip Gruszczyński: Institute of Environmental Engineering, Wrocław University of Environmental and Life Sciences, 50-363 Wrocław, Poland
Tomasz Kałuża: Department of Hydraulic and Sanitary Engineering, Poznań University of Life Sciences, 60-637 Poznań, Poland
Wojciech Czekała: Department of Biosystems Engineering, Poznań University of Life Sciences, 60-637 Poznań, Poland
Paweł Zawadzki: Department of Hydraulic and Sanitary Engineering, Poznań University of Life Sciences, 60-637 Poznań, Poland
Jakub Mazurkiewicz: Department of Biosystems Engineering, Poznań University of Life Sciences, 60-637 Poznań, Poland
Radosław Matz: Department of Hydraulic and Sanitary Engineering, Poznań University of Life Sciences, 60-637 Poznań, Poland
Maciej Pawlak: Department of Hydraulic and Sanitary Engineering, Poznań University of Life Sciences, 60-637 Poznań, Poland
Paweł Jarzembowski: Institute of Environmental Biology, Wrocław University of Environmental and Life Sciences, 50-375 Wrocław, Poland
Farokh Sahraei Nezhad: Department of Energy Technology, Royal Institute of Technology (KTH), 114 28 Stockholm, Sweden
Jacek Dach: Department of Biosystems Engineering, Poznań University of Life Sciences, 60-637 Poznań, Poland

Energies, 2024, vol. 17, issue 23, 1-23

Abstract: This investigation specifically aims to enhance the understanding of digestate flow and mixing behavior across typical temperatures in bioreactors in agricultural biogas plants, facilitating energy-efficient mixing. Experimental tests confirmed that digestate exhibits non-Newtonian characteristics, allowing its flow behavior to be captured by rheological models. This study validated that digestate rheology significantly varies with temperature, which influences flow resistance, mixing efficiency and overall energy requirements. Two rheological models—the Bingham and Ostwald models—were applied to characterize digestate behavior, with the Ostwald model emerging as the most effective for Computational Fluid Dynamic (CFD) simulations, given its balance between predictive accuracy and computational efficiency. Specifically, results suggest that, while three-parameter models, like the Herschel–Bulkley model, offer high precision, their computational intensity is less suitable for large-scale modeling where efficiency is paramount. The small increase in the accuracy of the shearing process description does not compensate for the significant increase in CFD calculation time. Higher temperatures were found to reduce flow resistance, which in turn enables increased flow rates and more extensive mixing zones. This enhanced mass transfer and mixing potential at elevated temperatures are especially pronounced in peripheral areas of the bioreactor, farthest from the agitators. By contributing a model for rheological behavior under realistic bioreactor conditions, this study supports the optimization of energy use in biogas production. These findings emphasize that temperature adjustments within bioreactors could serve as a reliable control strategy to maintain optimal production conditions while minimizing operational costs.

Keywords: digested pulp; agricultural biogas plant; influence of temperature; rheological parameters; flow behavior; digested pulp mixing (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2024
References: View references in EconPapers View complete reference list from CitEc
Citations:

Downloads: (external link)
https://www.mdpi.com/1996-1073/17/23/6111/pdf (application/pdf)
https://www.mdpi.com/1996-1073/17/23/6111/ (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:gam:jeners:v:17:y:2024:i:23:p:6111-:d:1536705

Access Statistics for this article

Energies is currently edited by Ms. Agatha Cao

More articles in Energies from MDPI
Bibliographic data for series maintained by MDPI Indexing Manager ().