Analysis of biomass pyrolysis products by advanced mass spectrometry
Résumé
Biomass pyrolysis generates volatile products which can be analysed (i) on-line by direct mass spectrometry or (ii) off-line after their condensation ("bio-oil"). In this talk we will present the main advances on these two topics conducted by CNRS Nancy in collaboration with USTC (Hefei, China) [1] and the mass spectrometry laboratory of Lorraine University (Metz, France) [2]. Primary pyrolysis volatiles were analysed on-line for the first time by synchrotron light photo-ionisation in Hefei (China). The synchrotron light offers an accurate, tunable and soft VUV source for ionising the labile oxygenated tar. A unique device has been developed by Pr F. Qi's group which combines a furnace for biomass pyrolysis, a sampling train for volatiles (through skimmers), an ionisation region where the synchrotron VUV light is focused, and a Q-TOF-MS (a triple quadrupole and a time -of-flight). Thanks to this set-up, a potential new intermediate from cellulose pyrolysis has been detected. The evolution of chemical "markers" from lignin, cellulose and hemicelluloses is studied as functions of biomass composition and time of conversion. Concerning off-line analysis of bio-oil, high resolution mass spectrometry (Fourier Transform Ion Cyclotron Resonance FT ICR) also called "petroleomic" method has been combined with GC*GC/MS-FID quantitative analysis to assess bio-oil composition. Laser desorption ionisation and electro spray ionisation were compared for petroleomic. The effect of catalytic treatment on lignin bio-oil composition is studied for a broad range of species: from C2 to C14 by GC analysis and from C8 to C37 by petroleomic. [1] Dufour, A., Weng, J.J., Jia, L.Y., Tang, X.F., (...) Qi, F. RSC Advances 3(14), 4786-4792, 2013. [2] Olcese R., Carré V., Aubriet F., Dufour A., Energy Fuels 27 (4), 2135-2145, 2013.