Effect of Rushton impeller speed on biogas production in anaerobic digestion of continuous stirred bioreactor
The formation of biogas in an anaerobic digester is a complex fermentation process of organic compounds involving microorganisms. The biogas production can be enhanced by using a mixer, which depends on its rotational speed. This study investigated the effect of mixer rotational speed on biogas p...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Penerbit Akademia Baru
2018
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| Subjects: | |
| Online Access: | http://irep.iium.edu.my/71228/ http://irep.iium.edu.my/71228/ http://irep.iium.edu.my/71228/1/71128_Effect%20of%20Rushton%20Impeller%20Speed.pdf |
| Summary: | The formation of biogas in an anaerobic digester is a complex fermentation process of
organic compounds involving microorganisms. The biogas production can be enhanced
by using a mixer, which depends on its rotational speed. This study investigated the
effect of mixer rotational speed on biogas production in an anaerobic continuous
stirred bioreactor with a computational approach. The purpose of this study is to find
the optimum speed of the mixer that produces the highest biogas production. The
finite volume method is used to simulate the synthropic digestion process experienced
by volatile fatty acids in a three-phase form. The mixer used is from the Rushton
impeller type, which rotates with speed variations of 50, 70, 100, 150, 200, and 300
rpm. The process takes place at temperature of 37o C in a bioreactor with a diameter
of 125 mm and high of 165 mm, with a substrate volume of 2000 ml. Chemical
reactions and thermohydraulic formulations were carried out using the species
transport, multiphase Eulerian model, and k- RNG turbulence model. It was found that
the mixer speed had a significant effect on the rate of biogas production, which at a
speed of 200 rpm gives the highest production rate of methane and carbon dioxide but
the lowest hydrogen. It is concluded that there is an optimum rotational speed in the
stirring process, which gives maximum biogas production. |
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