Torrefaction is a relatively new biomass pretreatment technology where the feedstock is heated (typically < 50 °C/min) in an inert environment up to a temperature of about 200-300 °C for a relatively long reactor residence time (from 30 min to 120 min, depending on the specific feedstock). The resulting torrefied material has low moisture content, high calorific values, increased resistance to moisture, and improved grinding properties [1]. Even though, torrefaction was originally developed as a treatment to improve the properties of biomass intended as a feedstock for thermochemical conversion pathways (i.e. combustion, pyrolysis and gasification) recently, it has also attracted some interest as a potential pretreatment of lignocellulosic biomass intended as feedstock for biorefinery (mainly for fermentable sugar production by enzymatic hydrolysis) [2-4]. A first attempt by Chiaramonti et al. [2] demonstrated that olive pruning debris torrefied under mild conditions (180-220°C) results into materials which can be enzymatically hydrolyzed and fermented into ethanol with yields close to those of the raw biomass. Again, Sheikh et al. [4] highlighted that, as long as the torrefaction conditions are not too severe (160-260 °C for 20-60 min), the saccharification yield of torrefied rice straw is much higher than that of untreated rice straw, thus resulting in a greater sugar release and an improved enzymatic digestibility. In order to confirm and strengthen the promising outcomes of these early studies, the potential to combine biomass torrefaction with biochemical conversion technologies (such as enzymatic hydrolysis and fermentation) has been further explored in the present work. In particular, two different agro-industrial residues, namely coffee silvers skin and brewery's spent grain, have been subjected to torrefaction under mild conditions of temperature (160-220 °C) and time (10-60 min), in both packed and fluidized bed reactors and then used as substrate for enzymatic hydrolysis tests. References [1] Nhuchhen, D.R., Basu, P., Acharya, B. A Comprehensive Review on Biomass Torrefaction. IJRER 2014 (2014) 1-56. [2] Chiaramonti, D., Rizzo A.M., Prussi, M., Tedeschi, S., Zimbardi, F., Braccio, G., Viola, E., Taddei Pardelli, P., 2nd generation lignocellulosic bioethanol: is torrefaction a pos-sible approach to biomass pretreatment?. Biomass Conv. Bioref. 1 (2011) 9-15. [3] Normark, M., Pommer, L., Grasvik, J., Hedenstrom, M., Gorzsas, A., Winestrand, S., Jonsson, L.J. Biochemical conversion of torrefied Norway spruce after pretreatment with acid or ionic liquid. Bioenerg. Res. 9 (2016), 355-368. [4] Sheikh, M.M., Kim, C.H., Park, H.J., Kim, S.H., Kim, G.C., Lee, J.Y., Sim, S.W., Kim, J.W. Effect of torrefaction for the pretreatment of rice straw for ethanol production. J. Sci. Food Agric. 93 (2013) 3198-204.
TORREFACTION AS A VERSATILE PRETREATMENT FOR MULTIPURPOSE BIO-FEEDSTOCK TRANSFORMATIONS
Paola Brachi;Maria Elena Russo;Giovanna Ruoppolo
2019
Abstract
Torrefaction is a relatively new biomass pretreatment technology where the feedstock is heated (typically < 50 °C/min) in an inert environment up to a temperature of about 200-300 °C for a relatively long reactor residence time (from 30 min to 120 min, depending on the specific feedstock). The resulting torrefied material has low moisture content, high calorific values, increased resistance to moisture, and improved grinding properties [1]. Even though, torrefaction was originally developed as a treatment to improve the properties of biomass intended as a feedstock for thermochemical conversion pathways (i.e. combustion, pyrolysis and gasification) recently, it has also attracted some interest as a potential pretreatment of lignocellulosic biomass intended as feedstock for biorefinery (mainly for fermentable sugar production by enzymatic hydrolysis) [2-4]. A first attempt by Chiaramonti et al. [2] demonstrated that olive pruning debris torrefied under mild conditions (180-220°C) results into materials which can be enzymatically hydrolyzed and fermented into ethanol with yields close to those of the raw biomass. Again, Sheikh et al. [4] highlighted that, as long as the torrefaction conditions are not too severe (160-260 °C for 20-60 min), the saccharification yield of torrefied rice straw is much higher than that of untreated rice straw, thus resulting in a greater sugar release and an improved enzymatic digestibility. In order to confirm and strengthen the promising outcomes of these early studies, the potential to combine biomass torrefaction with biochemical conversion technologies (such as enzymatic hydrolysis and fermentation) has been further explored in the present work. In particular, two different agro-industrial residues, namely coffee silvers skin and brewery's spent grain, have been subjected to torrefaction under mild conditions of temperature (160-220 °C) and time (10-60 min), in both packed and fluidized bed reactors and then used as substrate for enzymatic hydrolysis tests. References [1] Nhuchhen, D.R., Basu, P., Acharya, B. A Comprehensive Review on Biomass Torrefaction. IJRER 2014 (2014) 1-56. [2] Chiaramonti, D., Rizzo A.M., Prussi, M., Tedeschi, S., Zimbardi, F., Braccio, G., Viola, E., Taddei Pardelli, P., 2nd generation lignocellulosic bioethanol: is torrefaction a pos-sible approach to biomass pretreatment?. Biomass Conv. Bioref. 1 (2011) 9-15. [3] Normark, M., Pommer, L., Grasvik, J., Hedenstrom, M., Gorzsas, A., Winestrand, S., Jonsson, L.J. Biochemical conversion of torrefied Norway spruce after pretreatment with acid or ionic liquid. Bioenerg. Res. 9 (2016), 355-368. [4] Sheikh, M.M., Kim, C.H., Park, H.J., Kim, S.H., Kim, G.C., Lee, J.Y., Sim, S.W., Kim, J.W. Effect of torrefaction for the pretreatment of rice straw for ethanol production. J. Sci. Food Agric. 93 (2013) 3198-204.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
