Ullah Khan, Ershad
- Department of Energy and Technology, Swedish University of Agricultural Sciences
Abstract
This study assessed the thermo-economic performance of membrane distillation (MD) for concentrating nutrients and recover process water from digestate at a thermophilic biogas plant. The input data were derived from mapping the Uppsala Vatten och Avfall biogas system, present knowledge on anaerobic digestion process management and technologies for biogas system operating conditions in Sweden. The study evaluated the potential for recovering waste heat from the digestate effluent and boiler flue gas for use in the MD system. The thermal energy requirement, size, and separation efficiency of the MD unit were based on a previous laboratory study. The study assessed the overall energy efficiency and costs estimation of a full-scale codigestion plant with thermally integrated MD. Presented results shows that the proposed model of integrated MD system has the best thermal performance. The recovered waste heat contributed total thermal energy demand of MD and additionally it could save 19% boiler energy by heating incoming slurry. The results showed that the MD product water permeate was 3.5 L/(m2 h) at 65°C digestate inlet temperature. Specific heat demand for MD was 100 kWh/m3 with internal heat recovery. Cost estimation showed that the unit cost of MD permeate water was 3.6 €/m3 at a digestate feed temperature of 65°C. The economic assessment indicated that thermal integration of a biogas plant with MD could be economically feasible. However, long-term continuous studies are needed to determine impact of fouling and membrane lifetime.
Keywords
biogas plant; digestate; membrane distillation; concentrated nutrients and water recovery; thermo-economic analysis
Published in
Title: Volume 4: Proceedings of 11th International Conference on Applied Energy, Part 3, Sweden, 2019
Publisher: International Conference on Applied Energy
Conference
International Conference on Applied Energy 2019 Aug 12-15, 2019, Västerås, Sweden
SLU Authors
Nordberg, Åke
- Department of Energy and Technology, Swedish University of Agricultural Sciences
- Department of Energy and Technology, Swedish University of Agricultural Sciences
Associated SLU-program
STandUP for Energy
UKÄ Subject classification
Water Treatment
Bioenergy
Publication identifier
- ISBN: 978-91-985634-4-3
Permanent link to this page (URI)
https://res.slu.se/id/publ/105432