An approach for upgrading biomass and pyrolysis product quality using a combination of aqueous phase bio-oil washing and torrefaction pretreatment. (June 2017) - Chen, Dengyu
Highlights: A novel approach was performed to upgrade the quality of biomass pyrolysis products. Aqueous phase bio-oil washing pretreatment removed metals from the sample. Torrefaction reduced the oxygen but increased the metal content of cotton stalk. 3D FTIR results were consistent with the pyrolysis stages of the TG/DTG curve. Combined pretreatment reduced water and acid and increased phenol content of bio-oil. Abstract: Bio-oil undergoes phase separation because of poor stability. Practical application of aqueous phase bio-oil is challenging. In this study, a novel approach that combines aqueous phase bio-oil washing and torrefaction pretreatment was used to upgrade the biomass and pyrolysis product quality. The effects of individual and combined pretreatments on cotton stalk pyrolysis were studied using TG-FTIR and a fixed bed reactor. The results showed that the aqueous phase bio-oil washing pretreatment removed metals and resolved the two pyrolysis peaks in the DTG curve. Importantly, it increased the bio-oil yield and improved the pyrolysis product quality. For example, the water and acid content of bio-oil decreased significantly along with an increase in phenol formation, and the heating value of non-condensable gases improved, and these were more pronounced when combined with torrefaction pretreatment. Therefore, the combined pretreatment is a promising method, which would contribute to the development of polygeneration pyrolysis technology.