High yield methane generation from wet biomass and waste
Jeremy S. Luterbacher 1 , Morgan Fröling 2 , Frédéric Vogel 3 , François Maréchal 1 and Jefferson W. Tester 4
1 Ecole Polytechnique Fédérale de Lausanne 2 Chalmers University 3 Paul Scherrer Institute 4 Massachusetts Institute of Technology
Biomass feedstocks can efficiently be converted to Bio-Synthetic Natural Gas (bio-SNG) using catalytic supercritical water gasification.
Major advantages:
• Fuel can be used in the existing infrastructure
• Use of waste biomass (wet, containing lignocellulosic material)
• Recovery of inorganic material: use as a mineral fertilizer
• No drying or distillation steps
Process modeling and energy integration is used to simulate optimized Swiss industrial scale scenarios for manure and wood chips; life cycle assessment is used to assess the associated environmental impacts
Experimental
Resources, land use
Supply to network
Process modeling
Life cycle assessment Biomass
harvesting Catalytic supercritical gasification plant
Emissions
Energy integration + cost based choices among technology alternatives
Process modeling
Wood before and after processing (complete gasification). Gas composition: 49 vol% CH 4 , 43 vol% CO 2 and 8 vol% H 2 1 .
Photo source: NREL, Boulder, Colorado, USA Aspen plus ™
Energy integration using a burner for i n t e r n a l h e a t needs and a Rankine steam cycle for waste heat to electricity r e v a l o r i z a t i o n (13wt% of the crude product gas is burned)
Process efficiency (LHV basis) for d i f f e r e n t p r o d u c t i o n scenarios and for the different heat g e n e r a t i o n scenarios (turbine or burner)
Balance type Form Useful Energy [MW]
Manure (Large-scale) Manure (Small-scale) Wood
Turbine Burner Turbine Burner Turbine Burner
Consumption Biomass 251 251 8.37 8.37 50 50
SNG 118 155 3.94 5.18 22.8 35.6
Electricity 14.8 2.6 0.58 -0.020 4.8 1.7
Production
Total 133 158 4.52 5.16 27.6 37.3
Chemical 0.47 0.62 0.47 0.62 0.46 0.71
Efficiency
Total 0.53 0.63 0.54 0.62 0.55 0.75
Life cycle assessment LCA - About 10% Imbedded fossil energy for the supercritical water gasification processes; in comparison, the US corn grain to ethanol process has over 40% of imbedded fossil energy just in the form of natural gas 2 .
Avoiding emissions from spread manure ⇒ very beneficial for manure. Carbon footprint is of -0.6 Kg CO 2,eq. / MJ BIO-SNG .
Treating a waste and reducing the emissions associated to its use ⇒ a strong environmental performance for the manure conversion processes .
1
M. Waldner and F. Vogel: Renewable Production of methane from woody Biomass by Catalytic Hydrothermal Gasification”, Ind. Eng. Chem. Res.,44, 2005.
2
J. Johnson: “Technology assessment of Biomass Energy: A multi-objective, life cycle approach under uncertainty” Doctoral Thesis, MIT 2006
Results
Introduction Methodology
Scenarios investigated: large-scale manure (rail transport, 16 Mtons of manure/year), small-scale manure (no long- range transport, 0.54 Mtons/year), wood (truck transport, 0.14 Mtons/year)
Imbedded fossil energy for the large-scale manure (practically identical to the small-scale) and the wood conversion processes
The global warming potential is calculated for the modeled scenarios and benchmarked toward concurrent processes (anaerobic digestion of manure and conventional wood gasification)
Conclusions
Ecoivent data is used for modeling
Process modeling - Meeting internal heat requirements is done most efficiently using a burner + Rankine steam cycle.
Thermal efficiencies of 60% are obtained for manure and of 75% for wood
Transport
Primary fossil energy source Imbedded fossil energy [%]
Manure Wood
Crude oil 6.5 5.0
Natural gas 1.8 1.6
Coal 2.6 2.1
Total 10.8 8.7
Global warming potential over 100 years for the large-scale manure conversion process's cradle to gate life cycle
Methane production plant Rail transport
Tractor and trailer transport
Avoided production of fertilizer
Need for replacement
fertilizer
Avoided use of manure as a
fertiliser Avoided natural
gas extraction
Atmospheric CO
2uptake
Total
-7.00E-01 -6.00E-01 -5.00E-01 -4.00E-01 -3.00E-01 -2.00E-01 -1.00E-01 0.00E+00 1.00E-01 2.00E-01
Kg CO2 eq. /MJSNG
Electricity production Gas
purification
Comparison between the different global warming potential results for the processes of interest
Large-scale manure
Anaerobic digestion
Wood
Conventional gasification
Small-scale manure
-7.00E-01 -6.00E-01 -5.00E-01 -4.00E-01 -3.00E-01 -2.00E-01 -1.00E-01 0.00E+00 1.00E-01
Kg CO2 eq/MJSNG
Concurrent processes Supercritical water gasification processes
Gas Turbine Gas Turbine Gas Turbine
François Marechal Curriculum vitae
CURRICULUM VITAE MARECHAL François M. A.
Nationality : Belgian - 28/05/1963, Waimes (B) Civil : married, 3 children
Home: Chemin des vignes, 18, CH-1350 ORBE Tél : +41 24 441 45 23
Professional: LENI-ISE-STI-EPFL, CH-1015 Lausanne Tél: +41 21 693 35 16, Fax: +41 21 693 35 02
E-mail: Francois.Marechal@epfl.ch
Ph D. in Engineering– Chemical process engineer Maitre d’enseignement et de recherche
in the field of computer aided process and energy system engineering
Studies and qualifications
2005 : Maître d’enseignement et de recherche (EPFL) 2001 : EPFL : lecturer in the mechanical engineering school
2000 : Certificate : creation of university Spin-offs companies ( Certificat de formation à la création de Spin-offs universitaires) (University of Liège).
1999 : Qualification aux fonctions de maître de conférences par la section 62 (énergétique et génie des procédés) du Conseil National des Universités Français. (Qualification as assistant professor in the field of energy and process engineering from the National Council of the French Universities) 1995 : Ph. D. in engineering avec la plus grande distinction (with outstanding mention)
Titre de la thèse : Méthode d'Analyse et de Synthèse Energétiques des Procédés Industriels.
Title of the thesis : Method for the energy analysis and synthesis of industrial processes.
1981 - 1986: Chemical engineer from university of Liège (B) avec la plus grande distinction (with outstanding mention).
Executive summary
Teaching and research in the field of computer aided process and energy conversion systems analysis and synthesis. Application of thermo-economic modelling and multi-objective optimisation methods for the analysis, the design and the optimisation of industrial processes and energy conversion systems.
Major research topics : Computer aided process and energy conversion systems engineering. Methods for analysing and designing more sustainable and integrated energy conversion systems and industrial processes.
Research goals : Develop advanced computer aided methodologies combining thermodynamics and optimisation techniques in order to help engineers to study, analyse and design more efficient and more sustainable processes by optimally integrating in a systemic way conversion technologies, the use of renewable resources and the production of more sustainable products.
Major teaching activities : Advanced energetics (process integration), exergy analysis, power plants, process optimisation and modelling, energy audits and energy conversion systems for masters in mechanical, electrical, chemical and environment master programs, advanced master studies in energy and doctoral school in energy.
Teaching goals : Promote the use of project based and computer aided teaching. Integrate industrial partners in education by projects. Introduce sustainable development issues as part of the challenges in engineer's education and responsibility.
Short summary of my scientific contributions1
After a graduation in chemical engineering from the University of Liège, I have obtained a Ph. D. from the University of Liège in the LASSC laboratory of Prof. Kalitventzeff (former president of the European working party on computer aided process engineering). This laboratory was one of the pioneering
1 The numbers refers to publications in the bibliography section.
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