Studies in biogas technology. Part III. Thermal analysis of biogas plants

Prasad, CR and Sathyanarayan, SRC (1979) Studies in biogas technology. Part III. Thermal analysis of biogas plants. In: Sadhana - Academy Proceedings in Engineering Sciences, 2 (3). pp. 377-386.

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Abstract

A thermal model for a conventional biogas plant has been developed in order to understand the heat transfer from the slurry and the gas holder to the surrounding earth and air respectively. The computations have been performed for two conditions : (i) when the slurry is at an ambient temperature of 20°C, and (ii) when it is at 35°C, the optimum temperature for anaerobic fermentation. Under both these conditions, the gas holder is the major “culprit” with regard to heat losses from the biogas plant. The calculations provide an estimate for the heat which has to be supplied by external means to compensate for the net heat losses which occur if the slurry is to be maintained at 35°C. Even if this external supply of heat is realised through (the calorific value of) biogas, there is a net increase in the biogas output, and therefore a net benefit, by operating the plant at 35°C. At this elevated temperature, the cooling effect of adding the influent at ambient temperature is not insignificant. In conclusion, the results of the thermal analysis are used to define a strategy for operating biogas plants at optimum temperatures, or at higher temperatures than the ambient.

Item Type:	Journal Article
Publication:	Sadhana - Academy Proceedings in Engineering Sciences
Publisher:	Springer
Additional Information:	Copyright of this article belongs to Springer.
Keywords:	Thermal analysis - biogas plant - heating requirement - heat transfer - elevated temperature operation - heat loss from gas - slurry
Department/Centre:	Division of Mechanical Sciences > Mechanical Engineering
Date Deposited:	27 Dec 2010 12:25
Last Modified:	27 Dec 2010 12:25
URI:	http://eprints.iisc.ac.in/id/eprint/33922

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