a Energy Department (DENERG), Politecnico di Torino, Corso Duca degli Abruzzi 24 (TO) Turin 10129

1. Detection of Volatile Compounds Released from Dry Anaerobic Digestion of Organic Fraction of Municipal Solid Waste by PTR-ToF-MS. Davide Papurello*a,b, Christos Soukoulis b, Lorenzo Forlin b, Franco Biasioli b, Silvia Silvestri b, Massimo Santarelli a aEnergy Department (DENERG), Politecnico di Torino, Corso Duca degli Abruzzi 24 (TO) Turin 10129 bFEM – Fondazione Edmund Mach, Via E. Mach 1; 38010 San Michele all’Adige (Trento) Italy * Corresponding author +393402351692 – davide.papurello@polito.it Biogas from anaerobic digestion of OFMSW represents a clean alternative to fossil fuels for the energy production. CH4 and CO2 are the main components of biogas and SOFCs is the most promising technology for the energy production in terms of global efficiency and CO2tolerability. VOCs concentration levels in the biogas, mostly terpenes, sulfur and carbonyl compounds, could merge serious issues concerning the SOFCs operation. A robust and sensitive method for the VOCs real time monitoring is represented by direct injection mass spectrometry and the most promising one is the Proton Transfer Time of Flight Mass Spectrometry technique. The proton transfer from hydronium ions to volatile organic compounds is the chemical ionization method used for the real time monitoring. Materials and methods Dry anaerobic digestion of OFMSW was conducted in a pilot plant (FEM and Ambientalia srl, Italy). The Biogas produced was collected in Nalophan bags thermostatically controlled, and analyzed with a dilution ratio 1:10 N2 using a PTR-ToF-MS 8000 instrument (Ionicon, Austria). A heated PEEK line (110°C) allowed the direct connection with the sample, with an instrument configuration able to detect up to 400 m/z at E/N ratio of 155 Td. For every sample 30 average spectra have been acquired in a measurement time of 30s. For compounds with a Proton Affinity close to the water (H3O+ as ions source) e.g. H2S, a dynamic gas dilution calibration was made with a GCU system (Ionimed, Austria). Real time monitoring Fig. 1 Fig. 5 Fig. 3 Fig. 4 Fig. 6 Fig. 2 RH variability in biogas, especially for H2S, could be a serious issue for the quantification of concentration. In Figs.1,2 H2S and DMS calibration results are shown and RH dependence pointed out. Figs. 3,4,5 and 6 show respectively the time behavior of concentration for H2S, C2H6S, C4H8O and C10H16. Biological mechanisms for the bioconversion of MT and DMS in H2S, via the methanogenic mesophilic bacteria could be hypothesized. In the same way Fig.6 shows two burst peaks, the first one associated with the volatilization of alpha-pinene inherithed from the biomass, whereas the secondary one is related to microbial activity. Formation of 2-ketones, mainly 2-butanone, comes from the alcohols degradation. Fig. 7 shows the galvanostatic partial oxidation reforming of simulated biogas, used to control the temperature distribution of the cell surface and to limit the carbon deposition. SOFCs testing Fig. 7 Conclusions Real time monitoring was used also to identify the several digestion phases, some microbiological mechanisms among compounds of interest could be hypothesized as related with their time behavior. Further activities will develop on testing the filtration systems to abate the pollutants concentration in biogas before SOFCs feeding. A SOFC anode supported single cell was fed by simulated biogas mixture (CH4/CO2 + 1ppmv H2S) with dry–POx (partial oxidation) reforming for more than 200h, 1ppmv of H2S was shown as the tolerability limit for the reversible cell performance behavior.