First-Principles Kinetic Model for 2-Methyl- Tetrahydrofuran Pyrolysis and Combustion

First-Principles Kinetic Model for 2-Methyl- Tetrahydrofuran Pyrolysis and Combustion Ruben De Bruycker a, Luc-Sy Tran a,b,*, Hans-Heinrich Carstensen a, Pierre-Alexandre Glaude b, Frédérique Battin-Leclerc b, Guy Marin a, Kevin Van Geem a a Laboratory for Chemical Technology, Ghent University Laboratory for Chemical Technology, Ghent University b LRGP, CNRS, Université de Lorraine, Nancy, France * Now at Department of Chemistry, Bielefeld University, Germany http://www.lct.ugent.be ISCRE, Minneapolis Minnesota, USA, 13/06/2016 1

Thermochemical conversion of biomass GAS BIO-OIL CHAR CO H 2 NH 3 CO CH 2 4 H 2 O HCN C 2H 4 5wt% 35wt% 13wt% 85wt% Torrefaction Slow pyrolysis Fast pyrolysis Gasfication 20wt% 30wt% 75wt% 5wt% 75wt% 35wt% 12wt% 10wt% LIGNOCELLULOSIC BIOMASS 2

Model components for biomass pyrolysis H 2 O CH 4 H 2 C 2 H 4 CO CO 2 structural moieties found Study molecules with in biomass For example: 3

Is MTHF a suitable next-generation biofuel? LHV = 29 MJ l -1 RON = 86 MON = 73 D. M. Alonso, S. G. Wettstein, J. A. Dumesic, Green Chem. 15 (2013) 584-595 4

Outline Introduction Thermochemical conversion of biomass MTHF as fuel Experimental Tubular flow reactor for pyrolysis Low-pressure premixed laminar flame (speciation) Atmospheric premixed laminar flame (laminar burning velocity) Kinetic modeling development Results Species profiles Model validation Reaction path analysis Conclusion 5

Low-pressure premixed flame P = 6.7 kpa, φ = 0.7, 1.0, 1.3 Experimental Tubular flow reactor T = 913K 1073K P = 170 kpa, φ = F MTHF =1.68 10-4 mol/s F N2 =1.68 10-3 mol/s Height above burner Products Mole fraction Temperature Atmospheric premixed flame P = 101.3 kpa φ = 0.6 1.6 T unburned = 298 398K 6

Kinetic model development 1) Primary mechanism Describes the primary reactions of MTHF and derived radicals Kinetic parameters obtained from quantum chemical calculations (CBS-QB3), rate rules and analogy with THF 1 2) Secondary mechanism Describes the consumption molecular products characteristic for MTHF pyrolysis and combustion Consumption of large aldehydes/ketones using EXGAS 2 Aromatic formation pathways by Green and coworkers 3 3) Base mechanism Describes the combustion and pyrolysis of H 2, small hydrocarbons and oxygenates Propene oxidation model by Burke et al. 4 1 L.-S. Tran, M. Verdicchio, F. Monge, R. C. Martin, R. Bounaceeur, B. Sirjean, P.-A. Glaude, M. U. Alzueta, F. Battin-Leclerc, Combust. Flame 162 (2015) 2 V. Warth, N. Stef, P. A. Glaude, F. Battin-Leclerc, G. Scacchi, G. M. Côme, Combust. Flame 114 (1998) 3 S. S. Merchant. Molecules to Engines: Combustion Chemistry of Alcohols and their Application to Advanced Engines, MIT, USA, 2015 4 S. M. Burke, W. Metcalfe, O. Herbinet, F. Battin-Leclerc, F. M. Haas, J. Santner, F. L. Dryer, H. J. Curran, Combust. Flame 161 (2014) 8

CH 4 H 2 ISCRE, Minneapolis Minnesota, USA, 13/06/2016 CO H 2 O Pyrolysis C 2 H 4 C 2 H 6 CH 3 CHO Reactant C 2 H 2 CH 2 O Products formed by radical chemistry Products formed by unimolecular chemistry 10

Reaction path analysis P = 0.17 MPa T = 1000K ISCRE, Minneapolis Minnesota, USA, 13/06/2016 Unimolecular decompositon MTHF Reactions that involve the methyl group Products formed following scission of the ring bonds 1 1 R. De Bruycker, H.-H. Carstensen, M.-F. Reyniers, G. B. Marin, J. M. Simmie, K. M. Van Geem, Combust. Flame 164 (2016) 11

Low-pressure premixed flame φ = 1.0 50 species identified and quantified Major species H 2 O, CO 2, CO, H 2 Hydrocarbons, e.g. alkenes and aromatics Oxygenated intermediates, e.g. aldehydes and ketones 12

Low-pressure premixed flame φ = 0.7 φ = 1.0 φ = 1.3 13

Reaction path analysis Reaction path analysis P = 6.7 kpa T = 1300K h = 1.8mm Recombination reactions 14

Laminar burning velocity T unburned = 398K T unburned = 358K T unburned = 298K Highly sensitive towards small chemistry e.g. H + O 2 O + OH Low sensitivity to MTHF specific reactions Effect of methyl substitution Similar to hydrocarbons 15

Conclusion MTHF is a next-generation bio-derived fuel and its cyclic core is part of the biomass molecular structure Pyrolysis experiments were obtained in a tubular flow reactor Combustion experiments were performed using premixed laminar flames Low-pressure flames allowed to obtain speciation data Atmospheric flames were used to obtain laminar burning velocities A new detailed kinetic model is in good agreement with experimental data The pyrolysis experiments highlighted the importance of the methyl group for unimolecular decomposition reactions Combustion of MTHF is dominated by radical chemistry. Various intermediates are formed by recombination reactions. 17

Acknowledgement Long Term Structural Methusalem Funding by the Flemish Government European Research Council under the European Union s Seventh Framework Programme (FP7/2007-2013) / ERC grant agreement n 290793 Research Board of Ghent University (BOF) The SBO proposals Bioleum and Arboref supported by the Institute for promotion of Innovation through Science and Technology in Flanders (IWT) Clean ICE Advanced Research Grant of the European Research Council STEVIN Supercomputer Infrastructure at Ghent University 18

Back-up 20

Atmospheric premixed flame Burning velocity, S L, is the speed of the flame front relative to the unburnt reactants S L = f(φ, P, T u ) Heat flux method T r = T αr Fuel + Oxidizer Adiabatic flame if α = 0 21

Low-pressure premixed flame 22