Reducing agitation energy-consumption by improving rheological properties of corn stover substrate in anaerobic digestion

Tian, Libin; Shen, Fei; Yuan, Hairong; Zou, Dexun; Liu, Yan-Ping; Zhu, Baoning; Li, Xiujin

doi:10.1016/j.biortech.2014.03.023

Cited by 42 publications

(16 citation statements)

References 22 publications

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“…Thus, it was found that higher contents of long particle size increased the yield stress and viscosity values, and mechanical device application had a positive impact on rheological properties. A similar trend was reported with tests made with agricultural wastes as a substrate by different authors [14,38,44].…”

Section: Rheological Propertiessupporting

confidence: 88%

“…The yield stress values were three times higher for Site I than Site II at similar TS. According to Tian et al [38], the required energy for appropriate mixing of the digester may be reduced by 9.2% with a particle size reduction from 20 to 80 mesh (with corn stover as a substrate). In addition, the mixing energy is (in first approximation) directly proportional to the apparent viscosity of the digester content [51].…”

Section: Rheological Propertiesmentioning

confidence: 99%

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Methods for the Evaluation of Industrial Mechanical Pretreatments before Anaerobic Digesters

Fernandez¹,

Ramirez²,

Franco³

et al. 2020

Molecules

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Different methods were tested to evaluate the performance of a pretreatment before anaerobic digestion. Besides conventional biochemical parameters, such as the biochemical methane potential (BMP), the methane production rate, or the extent of solubilization of organic compounds, methods for physical characterization were also developed in the present work. Criteria, such as the particle size distribution, the water retention capacity, and the rheological properties, were thus measured. These methods were tested on samples taken in two full-scale digesters operating with cattle manure as a substrate and using hammer mills. The comparison of samples taken before and after the pretreatment unit showed no significant improvement in the methane potential. However, the methane production rate increased by 15% and 26% for the two hammer mills, respectively. A relevant improvement of the rheological properties was also observed. This feature is likely correlated with the average reduction in particle size during the pretreatment operation, but these results needs confirmation in a wider range of systems.

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Section: Rheological Propertiessupporting

confidence: 88%

Section: Rheological Propertiesmentioning

confidence: 99%

Methods for the Evaluation of Industrial Mechanical Pretreatments before Anaerobic Digesters

Fernandez¹,

Ramirez²,

Franco³

et al. 2020

Molecules

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show abstract

“…Particularly for substrates with large effects on anaerobic sludge rheology, the use of pre-treatment methods before AD should be considered, since these have been observed to decrease the rheological characteristics of CSTBR sludge (e.g. Tian et al 2014;Goel et al 2004;Perez-Elvira et al 2010). In particular the beneficial effects of pre-treatment methods on power demand for pumping and stirring should be considered just as important as the increased biogas production.…”

Section: Discussionmentioning

confidence: 99%

Anaerobic Digester Fluid Rheology and Process Efficiency : Interactions of Substrate Composition, Trace Element Availability, and Microbial Activity

Šafarič

2019

Linköping Studies in Arts and Sciences

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As the anthropogenic greenhouse gas emissions continue imposing stress on our environment, it is becoming increasingly important to identify and implement new renewable technologies. Biogas production through anaerobic digestion has a great potential, since it links waste treatment with extraction of renewable energy, enabling circular bio-economies that are vital for a sustainable future.For biogas to have an important role as a renewable energy carrier in society, the scale of its production will need to be increased substantially. New substrates need to be introduced along with raising organic loading rates of the reactors to increase the rate of biogas production. This contributes to challenges in maintaining process stability, thus increasing the risk for process disturbances, including problems that were not commonly encountered before. These difficulties may be particularly pronounced when a broad range of new, largely untested substrates are introduced, leading to an increased heterogeneity of organic material entering the reactors. In the case of currently the most common reactor type; the continuous stirred-tank biogas reactor (CSTBR); such problems may include shifts in rheology (i.e. fluid behaviour) of the anaerobic digester sludge. This may lead to increased energy consumption and decreased digester mixing efficiencies, which in turn may lead to inefficient biogas processes, ultimately decreasing the economic and environmental viability of biogas production. Much is still unknown regarding how rheology shifts happen in biogas reactors, particularly when it comes to what role the substrate plays in rheological dynamics, as compared to the microbial community during varying levels of biogas process stability.This thesis elucidates the interactions between substrate type, microbial community and its metabolic activity, and anaerobic sludge rheology. A number of sludge samples from mesophilic and thermophilic CSTBRs digesting a broad range of substrates was analysed for their rheology. The specific effects of individual substrate types on CSTBR sludge rheology and the resulting implications for stirring power requirements and mixing efficiency were investigated. In order to also asses to which extent the microbial metabolism affects rheology at different levels of process disturbance, an experiment with a trace-element-induced inhibition of specific metabolic pathways under mesophilic reactor conditions was performed. This was used to identify the sequence of different interactions that occur in the reactor after the process begins to fail, and to evaluate how these interactions link to changes in digester sludge rheology. Finally, a case study of a disturbed thermophilic anaerobic digestion process was performed, including the monitoring of the response of rheology in relation to process stability, which was modified by changing trace element concentrations. The use of artificial substrate without polymeric compounds in both cases allowed for an evaluation of effects of the microbial community and its ...

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“…This led to relatively small reduction from 25 to 21% insoluble solids, which was insufficient in itself to account for the total observed fall in viscosity [31]. Other workers have investigated the influences of biomass particle size on biomass suspension rheology and subsequent enzyme digestion but have not considered the role of enzyme digestion directly on size and length reduction [32,33].…”

Section: Standard Msw Biofibermentioning

confidence: 99%

Enzyme digestion of biofiber from mechanical heat treated municipal solid waste: Accessing kinetic and rheological design data using a pilot-scale high-solids mixer

Ibbett

Tucker

McKechnie

et al. 2020

Biomass and Bioenergy

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Reducing agitation energy-consumption by improving rheological properties of corn stover substrate in anaerobic digestion

Cited by 42 publications

References 22 publications

Methods for the Evaluation of Industrial Mechanical Pretreatments before Anaerobic Digesters

Methods for the Evaluation of Industrial Mechanical Pretreatments before Anaerobic Digesters

Anaerobic Digester Fluid Rheology and Process Efficiency : Interactions of Substrate Composition, Trace Element Availability, and Microbial Activity

Enzyme digestion of biofiber from mechanical heat treated municipal solid waste: Accessing kinetic and rheological design data using a pilot-scale high-solids mixer

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