CFD simulation of mixing in anaerobic digesters

Terashima, Mitsuharu; Goel, Rajeev; Komatsu, Kazuya; Yasui, Hidenari; Takahashi, Hiroshi; Li, Y.Y.; Noike, Tatsuya

doi:10.1016/j.biortech.2008.07.069

Cited by 145 publications

(71 citation statements)

References 22 publications

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“…14 is associated with the effective volume and flow pattern; hence on the one hand, it is related to the working performance of the anaerobic reactor, and on the other hand, it is influenced by hydraulic characteristics (Terashima et al 2009). Persson et al (1999) categorized the hydraulic efficiency into three groups: good (k p [ 0.75), satisfactory (0.75 B k p C 0.50) and poor (k p \ 0.50).…”

Section: Hydraulic Efficiencymentioning

confidence: 99%

Hydrodynamic behaviour and its effects on the treatment performance of panelled anaerobic baffle-cum filter reactor

Renuka

Mohan

Raj

2015

Int. J. Environ. Sci. Technol.

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The aim of this paper was to present the influence of hydraulic behaviour in the treatment of sewage (domestic wastewater) using panelled anaerobic baffle-cum filter reactor (PABFR). The PABFR has five compartments of equal size in which the first three compartments operate as anaerobic baffled reactor (ABR) followed by anaerobic filters (AF). The combined reactor has a great potential for its application due to its panelled structure and arrangement of baffles inside each compartment. Hydrodynamic behaviour of the reactor was determined by means of a pulse tracer test and by calculating the residence time distribution curves at different flow rates. At high flow rates [with hydraulic retention time (HRT) \4 h], the mixing pattern in ABR showed a completely mixed type with a maximum dead space of 14 % and as the flow decreased (HRT of 8 and 12 h), the ABR's mixing behaviour was intermediate between plug flow and completely mixed. In the case of AF, as the flow increased, the dispersion was intermediate between completely mixed and plug flow, and as the flow rate decreased, the reactor became completely plug flow with the dead space ranging between 2.2 and 7.4 %. On the whole, PABFR treatment performance in terms of chemical oxygen demand removal was 90, 89 and 64 % for 12-, 8-and 4-h HRT, respectively, which clearly shows the correlation between mixing and reactor process performance.Thus, the outcome of this research in general highlights the importance of hydrodynamic behaviour for a better operation of the reactor.

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Section: Hydraulic Efficiencymentioning

confidence: 99%

Hydrodynamic behaviour and its effects on the treatment performance of panelled anaerobic baffle-cum filter reactor

Renuka

Mohan

Raj

2015

Int. J. Environ. Sci. Technol.

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“…The actual setting and operations of the stirring machine are determined by the physical and chemical attributes of the materials fed into the tank, and the shape and size of the stirring space are also something to be considered. To satisfy requirements (consistent temperature, physical and various stirring machines is possible as well [8]. Hydraulic resistance has a significant impact on energy consumption, which becomes substantial in case of big tanks.…”

Section: Introductionmentioning

confidence: 99%

Conditions of using propeller stirring in biogas reactors

Bártfai¹,

Oldal²,

Tóth³

et al. 2015

HAE

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Preparing and further cutting of bovine dung which also contains straw, and of corn silage happens in special cutters, from which it is fed into the pre-fermentation tank. The primary mixing of liquid manure, and sewage water, including other fluids happens in a heated pre-container. The foodstuffs which are their expiration dates, and various other waste (household waste, greasy materials from washing, depleted frying oil, fats from grease-traps, etc.) are accepted in the pounder. This is where the cutting and separation of wrappings of boxed products happens as well, after which the thin parts are fed into an autoclave, and kept at 70oC for at least four hours to sterilise them.The profit-oriented biogas plants consider the static, calculable production of electric and heat energy a fundamental goal, which requires the gas production to be continuous and free of hindrances [1]. In case of these factories, the gas yield for time unit may be lowered by various operation factors, but mainly malfunctions (errors, the foam within fermentation tanks from time to time, etc.). Incorrectly mixing or homogenising the materials arriving in the fermentation tanks also counts as a hindering operation factor. Our work details the basic questions of how the stirring inside fermentation tanks happens physically.

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“…Terashima et al (2009) evaluated the field of velocities and concentrations for an organic substrate with non-Newtonian properties in an anaerobic digester with an internal circulation tube. Mendoza et al (2011) obtained numerical results of the distribution of velocity fields in a cylindrical anaerobic digester with jet mixing.…”

Section: Introductionmentioning

confidence: 99%

Study of the Process of Hydraulic Mixing in Anaerobic Digester of Biogas Plant

Karaeva

Khalitova

Kovalev³

et al. 2015

Chemical and Process Engineering

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Two systems of hydraulic mixing in a vertical cylindrical anaerobic digester: standard and modernised are discussed in the paper. Numerical investigations that were carried out are focused on a study of hydrodynamic processes in an aerobic digester using two various systems of hydraulic mixing as well as on analysis of the efficiency of methane fermentation process accomplished under different geometric parameters of an anaerobic digester and systems of hydraulic mixing.

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CFD simulation of mixing in anaerobic digesters

Cited by 145 publications

References 22 publications

Hydrodynamic behaviour and its effects on the treatment performance of panelled anaerobic baffle-cum filter reactor

Hydrodynamic behaviour and its effects on the treatment performance of panelled anaerobic baffle-cum filter reactor

Conditions of using propeller stirring in biogas reactors

Study of the Process of Hydraulic Mixing in Anaerobic Digester of Biogas Plant

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