AARHUS UNIVERSITY. Aarhus University Renewable Energy

Transcription

1 Aarhus University Renewable Energy 1

2 15 global challenges

3 The challenge Carbon fossils (Oil, gas, coal) Renewable Energy (electricity) Energy Materials Feed Increasing value +CO 2 Surplus CO 2 accumulation Food Biomass Linear carbon flux To reduce the linear flux of carbon 3

4 ENG/Physics New efficient PV technology AARHUS Towards a solution ENG Projects: - Chemical methanisation (Haldor Topsøe) - Biological methanisation (IF Electrogas) Renewable Energy (Electricity) To compensate for loss of entropy in carbon cycle Energy storage Energy Materials ENG Projects: 10 biogas projects Hydro Thermal Conversion (Biovalue) Feed Agriculture Biomass Food Recycle Waste +CO 2 ENG Projects: Biovalue SPIR Green Protein New Substrate circular carbon flux Technology and knowledge to create the circular flux of carbon 4

5 Så hvorfor methanisering A fossil free energy and materials system (several political agendas) Plentiful renewable electricity in the future (sun and wind double globally in installed capacity every 22 months, price half 3-4 years) Huge demand for energy conversion and energy storage in the future grid Huge demand for reduction of CO 2 for materials (polymers) and transport fuel (aviation) Shortage of fertile arable land (reserved for food and feed production) Future bioenergy mainly/only from waste (slurry, straw, sludge, food waste) 5

6 Forslåede teknologier Biomethanisering direkte på katodeoverflader Biomethanisering med H 2 som energikilde Katalytisk methanisering (Sabatier proces) H 2 som energikilde Kulstofkilde typisk CO 2 (eller CO) 6

7 Waste Anaerobic digestion H 2 producers Each m 3 of reactor volume produce > 5m 3 H 2 pr day! Acetate oxidation H 2 consumers Energy

8 Et AU forslag: Microbial conversion of CO 2 to CH 4 inside main reactor Electron donor: H 2 O (?) Energy source: Electricity in the form of H 2 or e- Carbon source: CO 2 from fermentation of organic waste Disse ideer forsøges realiseret I DSF / Innofond projekt Electrogas (AU, SDU, Uni Queensland, Stanford, USC, Xergi, Landia) 8

9 Grundlæggende 2 ideer i Electrogas 1. Addition of H 2 to a AD reactor (separate electrolysis step) 2. Microbial Electrosynthesis on a cathode surface Why 2? Heavily advertised in the literature, scientifically interesting, could be interesting for semi bulk, not fuel, chemicals (Amino acids?) 9

10 H 2 tilsætning til hovedreaktor Requires H 2 production (which will be temporary for cost reasons?) Mass transfer challenge vastly underestimated in advertised solutions How low can we go in off gas CO 2? (microbiology limitations?) Medium TRL 10

11 Mikrobiel elektrosyntese Lav TRL.. 11

12 HYCON to the m scale (because mass transfer is not scaleable.) 12

13 Thermodynamics, diffusion law and microbial metabolism constraints dictate: Free hydrogen concentration in the reactor is very low (0,007-0,07 μm) H 2 average lifetime < 30mS Practically no H 2 is lost from the reactor Distance between producers and consumers less than a few μm Syntrophic aggregate 13

14 HYCON observations from adding H 2 : H 2 producers carry on unaffected in lab scale short term additions, although thermodynamics predicts otherwise in a homogeneous mixed system H 2 consumers rapidly consume added H 2 and seems only limited by the availability of CO 2 How? Hycon product: New H 2 microsensor for sulfidic environments (Revsbech) Depth (µm) Ascending H 2 bubble H2 (µm) aggregate Source: Hycon 2014

15 Microbial electrosynthesis Very low TRL (Technology Readiness Level) Interesting mechanism (unexploited potential?) Describe mechanisms Evaluate potential 15

16 BoE calculation Summers (2013): autotroph iron oxidizer: 0.075pmol cell -1 h -1 MES rate or 5 A m -2 Soussan (2013): Geobacter 30A m -2 on stainless steel cathode (efficiency not recorded) Ganique (2015): Mixed culture 6.3 A m -2 (approx 30% coulumbic efficiency) Assumption SoA MES: 5 A m -2 (3.12 *10 19 e - m 2 s -1 ) e- flux reactor: (50 ml H 2 m -3 s -1 ) = mol e- m -2 s -1 = 2.9 * e - m 3 s -1 So something like 100 m 2 m -3 of cathode surface (and then consider anode + charge transfer..) 16

17 Strategic vision: < 100% CH 4 + > 0 % CO 2 50% CH % CO 2 H 2 17

18 Some HYCON achievements Significant advances in our understanding of energy flux within anaerobic microbiology. Development of 1. generation prototype for full scale low cost technology for H 2 addition Significant contribution towards a fossil free, sustainable and reliable energy system And..visit our posters. 18

19 HYCON group Anders Feilberg Alastair ward Daniel Mulat Viktor Milkevych Anders Peter Adamsen Lars DM Ottosen Niels Vinther Voigt Michael Kofoed Jeppe Lund Freya Mosbæk Anders Peter Jensen Niels Peter Revsbech Emilio Garcia Lobles Michael Nielsen

20 Consumption evolvement 20