Identification of volatile organic compounds in the gaseous fraction from soybean residue pyrolysis

IMWINKELRIED, GABRIEL; CARLA. S. FERMANELLI; CLARA SAUX; MARIANO A TERUEL; CYNTHIA RIVELA, MARIA BELEN BLANCOAND MARIANO A. TERUEL

Rennes

Simposio; 26th International Symposium on Gas Kinetics and Related Phenomena ? GK2022; 2022

RSC Gas Kinetic group

The depletion of non renewable raw materials has motivated biomass valorization for ene rgyproduction. Some agro industrial wastes, including soybean hulls, are processed through athermochemical transformation process at high temperatures and in an inert atmosphere pyrolysisleading to the formation of bi ochar, bioliquid and a gas fractio n as products 1 . The identification of volatile organic compounds (VOCs) in the gas fraction is essential to predict air quality impacts by thestudy of their gas phase reactions with atmospheric oxidants In this work, the experiments were performed by triplicate in a temperature range of 400 600 °Cfor 10 min with N 2 flow of 60 m L min into a fixed bed glass tubular reactor located inside an oven.The gases were captured in a collapsible Tedlar chamber of 5 liters capacity in order to capture andpreconcent rate the gas sample through the solid phase microextraction (SPME) technique to finally be desorbed in a mass chromatograph coupled to mass spectrometry (GC MS). Figure 1 depicts the predominance of aromatic hydrocarbons (such as toluene, ethylbenzene, phe nol), oxygenated compounds (such as 2 methylpropanal, 2 methylbutanal, 3 methylbutanal), alkanes (heptane and octane), alkenes (such as 1 hexene, 1 octene, 2 octene) and furans (2 methylfuran and 2,5 dimethylfuran) as the main chemical compounds for the ra nge of reaction temperatures.The highest relative chromatographic area (RCA) is represented by aromatic hydrocarbons with methylbenzeneas the major compound with 22% RCA at 500 °C. Figure 2illustrates the performance of the three pyrolysis reaction pr oducts, where the maximum production of bioliquid(44%) and syngas (34%) is achieved at 600 °C. In contrast,the production of biochar is maximized at 400 °C (62%)over the other two fractions . This performance has been previously demonstrated for the pyro lysis of this biomass. 2Finally, soybean residuespyrolysis causes a great diversity of VOC's, where methylbenzene is themost prevalent compound for all temperatures, an aromatic hydrocarbon of high relevance due to human health and environmental hazards . On the other hand, the increase in pyrolysis temperature is proportional t o the produc tion of the bioliquid and gas fractions.[1]Garcia Perez, M., Chaala, A., Pakdel, H. Biomass Bioenergy. 31 222 242 ([2] Tor o Trochez, J. L., Carrillo Pedraza, E. S., Bustos Martínez, D., García Mateos, F. J.,Ruiz Rosas, R. R., Rodríguez Mirasol, J., Cordero, T. B ioresource Technology Reports . 6 183 189 2019