Heat and energy requirements in thermophilic anaerobic sludge digestion

G.D. Zupančič and M. Roš

Renewable Energy, 2003, vol. 28, issue 14, 2255-2267

Abstract: The heating requirements of the thermophilic anaerobic digestion process were studied. Biogas production was studied in laboratory experiments at retention times from 1 to 10 days. The data gathered in the experiments was then used to perform a heat and energy analysis. The source of heat was a conventional CHP unit system. The results showed that thermophilic digestion is much faster than mesophilic digestion and therefore produces more biogas in a shorter time or at smaller digester volumes. The major part of the heating requirements consisted of sludge heating. The heat losses of the digester were only 2–8% of the sludge heating requirements. The heating requirements in thermophilic digestion are about twice those of mesophilic digestion. Therefore a CHP unit system cannot cover all of the needs for successful operation of thermophilic digestion. Heat regeneration was introduced as a solution. Heat is regenerated from the sludge outflow at a temperature of 50–55 °C and transferred to the cold inflow sludge at a temperature of 11 °C. Enough heat is regenerated in a conventional counter flow heat exchanger to bring the thermophilic process to the same level as the mesophilic one. Considering the smaller digester volumes and the relatively small investment in the regenerative equipment, the construction of thermophilic digestion systems may be a very good alternative to conventional mesophilic sludge digestion systems.

Keywords: Anaerobic sludge digestion; Biogas production; Heat requirements; Heat regeneration; Sludge heating; Thermophilic sludge digestion (search for similar items in EconPapers)
Date: 2003
References: View complete reference list from CitEc
Citations: View citations in EconPapers (23)

Downloads: (external link)
http://www.sciencedirect.com/science/article/pii/S0960148103001344
Full text for ScienceDirect subscribers only

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:eee:renene:v:28:y:2003:i:14:p:2255-2267

DOI: 10.1016/S0960-1481(03)00134-4

Access Statistics for this article

Renewable Energy is currently edited by Soteris A. Kalogirou and Paul Christodoulides

More articles in Renewable Energy from Elsevier
Bibliographic data for series maintained by Catherine Liu ().