title: High-pressure anaerobic digestion up to 100 bar: influence of initial pressure on production kinetics and specific methane yields.
abstract: To ensure an efficient use of biogas produced by anaerobic digestion, in some cases it would be advisable to upgrade the biogenic gases and inject them into the transnational gas grids. To investigate biogas production under high-pressure conditions up to 100 bar, new pressure batch methane reactors were developed for preliminary lab-scale experiments with a mixture of grass and maize silage hydrolysate. During this investigation, the effects of different initial pressures (1, 50 and 100 bar) on pressure increase, gas production and the specific methane yield using nitrogen as inert gas were determined. Based on the experimental findings increasing initial pressures alter neither significantly, further pressure increases nor pressure increase rates. All supplied organic acids were degraded and no measurable inhibition of the microorganisms was observed. The results show that methane reactors can be operated at operating pressures up to 100 bar without any negative effects on methane production.
authors.affiliation: a State Institute of Agricultural Engineering and Bioenergy, University of Hohenheim , Stuttgart , Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Merkle
authors.affiliation: b DVGW - Research Centre at the Engler-Bunte-Institute, Karlsruhe Institute of Technology (KIT) , Karlsruhe , Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Baer
authors.affiliation: a State Institute of Agricultural Engineering and Bioenergy, University of Hohenheim , Stuttgart , Germany.
authors.forename: Nicola Leonard
authors.initials: NL
authors.lastname: Haag
authors.affiliation: a State Institute of Agricultural Engineering and Bioenergy, University of Hohenheim , Stuttgart , Germany.
authors.forename: Simon
authors.initials: S
authors.lastname: Zielonka
authors.affiliation: b DVGW - Research Centre at the Engler-Bunte-Institute, Karlsruhe Institute of Technology (KIT) , Karlsruhe , Germany.
authors.forename: Felix
authors.initials: F
authors.lastname: Ortloff
authors.affiliation: b DVGW - Research Centre at the Engler-Bunte-Institute, Karlsruhe Institute of Technology (KIT) , Karlsruhe , Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Graf
authors.affiliation: a State Institute of Agricultural Engineering and Bioenergy, University of Hohenheim , Stuttgart , Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Lemmer
mesh_terms: D000693:Anaerobiosis; D019149:Bioreactors; D007700:Kinetics; D008697:Methane / Q000378:metabolism*; D006109:Poaceae; D011312:Pressure; D012820:Silage; D003313:Zea mays
chemical_list: D008697:Methane
keywords: Gompertz equation; High pressure; biogas; compressibility factor; two-stage anaerobic digestion