High yield methane generation from wet biomass and waste

Jeremy S. Luterbacher1, Morgan Fröling2, Frédéric Vogel3, François Maréchal1 and Jefferson W. Tester4

1Ecole Polytechnique Fédérale de Lausanne 2Chalmers University 3Paul Scherrer Institute 4Massachusetts 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% CH4, 43 vol% CO2 and 8 vol% H2

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) WoodTurbine Burner Turbine Burner Turbine Burner

Consumption Biomass 251 251 8.37 8.37 50 50SNG 118 155 3.94 5.18 22.8 35.6

Electricity 14.8 2.6 0.58 -0.020 4.8 1.7ProductionTotal 133 158 4.52 5.16 27.6 37.3

Chemical 0.47 0.62 0.47 0.62 0.46 0.71EfficiencyTotal 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 gas2.

Avoiding emissions from spread manure ⇒ very beneficial for manure. Carbon footprint is of -0.6 Kg CO2,eq./MJ BIO-SNG.

Treating a waste and reducing the emissions associated to its use ⇒ a strong environmental performance for the manure conversion processes .

1M. Waldner and F. Vogel: Renewable Production of methane from woody Biomass by Catalytic Hydrothermal Gasification”, Ind. Eng. Chem. Res.,44, 2005.2J. 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 WoodCrude oil 6.5 5.0

Natural gas 1.8 1.6Coal 2.6 2.1Total 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 naturalgas extraction

Atmospheric CO2

uptake

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

CO

2 eq

. /M

JSN

G

ElectricityproductionGaspurification

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

CO

2 eq/

MJS

NG

Concurrent processes

Supercritical water gasification processes

Gas Turbine Gas TurbineGas Turbine

François Marechal Curriculum vitae

CURRICULUM VITAE

MARECHAL François M. A.Nationality : Belgian - 28/05/1963, Waimes (B)Civil : married, 3 childrenHome: Chemin des vignes, 18, CH-1350 ORBETél : +41 24 441 45 23Professional: LENI-ISE-STI-EPFL, CH-1015 LausanneTél: +41 21 693 35 16, Fax: +41 21 693 35 02

E-mail: Francois.Marechal@epfl.ch

Ph D. in Engineering– Chemical process engineerMaitre 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 school2000 : 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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