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Effect of operating conditions and reactor configuration on efficiency of full-scale biogas plants. Irini Angelidaki, Kanokwan Boe and Lars Ellegaard. Presentation content. Biogas in Denmark: A typical Centralized Biogas Plant Main Results of the investigation Conclusions.
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Effect of operating conditions and reactor configuration on efficiency of full-scale biogas plants Irini Angelidaki, Kanokwan Boe and Lars Ellegaard
Presentation content • Biogas in Denmark: A typical Centralized Biogas Plant • Main Results of the investigation • Conclusions
Typical centralized biogas plant Ribe biogas plant
Full-scale investigation • Process stability • Process efficiency • Microbiology
Potential methods to improve recovery efficiency from manure • Increase stabilily of the digestion process • Pre-treatment of incoming substrate (to increase degradability) • Increase retention time of the manure reactor(s) • Arrange post-digestion systems (to increase degradation efficiency)
55oC 25oC 20oC 15oC 55oC 55oC 25oC 20oC 15oC Residual methane production
>15% 10-15% < 10% Restgastab i forhold til total produktion
INCREASING TEMPERATURE Samples previously incubated at 10-15C for a long period have been moved to process temperature (37-54C):
INNOVATIVE SOLUTIONS • SITUATION: • The majority of the biogas plants have Reactors with good efficiency; • Many plants are loosing a lot and the gap between the theoretical and the practical potential is still wide; MAIN OBSTACLE: hydrolysis is the real rate limiting step for the further methanogenesis increase HRT to provide a better substrate hydrolysis SOLUTIONS: TRADITIONAL SOLUTIONS Increase the HRT in main reactor INNOVATIVE SOLUTIONS New process configurataion: Utilization of the After-Storage.
Conclusions • Significant amounts of CH4 are lost (5-30%) • Plants with HRT< 15 days are lossing more CH4 from the main reactor • Post-digestion is highly influenced by the temperature • Post-digestion at low temperature are increasing the total methane potential of the material • Manure-plants are dominated by Methanosarcina, while sludge plants by Methanosaeta.
Acknowledgements • The study was funded by the Danish Energy Agency,“Development of Renewable Energy” • The operational staff of the Biogas Plants participating in the investigation is greatly acknowledged • Researchers: • Kanokwan Boe • Lars Ellegaard • Dimitar Karakshlev • Damien Batstone • Irini Angelidaki • Students: • Simone Labo • Lucía Fernández García • Eva Arler • He Zhen • Chao Pan • Troels Hilstrøm • Søren H. Laursen • Technicians: • Hector Garcia • Majbrit Staun Jensen