ABSTRACT The technology of fast pyrolysis is regarded as a promising route to convert lignocellul... more ABSTRACT The technology of fast pyrolysis is regarded as a promising route to convert lignocellulose biomass into liquid oil (bio-oil) which can be upgraded to transportable fuels and intermediate chemicals. However, the bio-oil is a complex mixture of organic compounds that are obtained in a non-equilibrium state. Therefore, the physical properties of bio-oil such as density, acidity, viscosity and chemical compositions change during storage and transportation, which is one of the most challenging problems in using bio-oil for any applications including as transportation fuels. This paper summarizes phenomena that lead to unstable properties of bio-oil and reviews recent developments in techniques used to improve the bio-oil properties for making bio-oil a stable intermediate product that can be easily handled and processed.
The pyrolysis behaviors of four types of pretreated switchgrass (torrefied at 230 and 270°C, dens... more The pyrolysis behaviors of four types of pretreated switchgrass (torrefied at 230 and 270°C, densification, and torrefaction at 270°C followed by densification) were studied at three temperatures (500, 600, 700°C) using a pyroprobe attached to a gas chromatogram mass spectroscopy (Py-GC/MS). The torrefaction of switchgrass improved its oxygen to carbon ratio and energy content. Contents of anhydrous sugars and phenols in pyrolysis products of torrefied switchgrass were higher than those in pyrolysis products of raw switchgrass. As the torrefaction temperature increased from 230 to 270°C, the contents of anhydrous sugars and phenols in pyrolysis products increased whereas content of guaiacols decreased. High pyrolysis temperature (600 and 700°C as compared to 500°C) enhanced decomposition of lignin and anhydrous sugars, leading to increase in phenols, aromatics and furans. Densification enhanced depolymerization of cellulose and hemicellulose during pyrolysis.
ABSTRACT The technology of fast pyrolysis is regarded as a promising route to convert lignocellul... more ABSTRACT The technology of fast pyrolysis is regarded as a promising route to convert lignocellulose biomass into liquid oil (bio-oil) which can be upgraded to transportable fuels and intermediate chemicals. However, the bio-oil is a complex mixture of organic compounds that are obtained in a non-equilibrium state. Therefore, the physical properties of bio-oil such as density, acidity, viscosity and chemical compositions change during storage and transportation, which is one of the most challenging problems in using bio-oil for any applications including as transportation fuels. This paper summarizes phenomena that lead to unstable properties of bio-oil and reviews recent developments in techniques used to improve the bio-oil properties for making bio-oil a stable intermediate product that can be easily handled and processed.
The pyrolysis behaviors of four types of pretreated switchgrass (torrefied at 230 and 270°C, dens... more The pyrolysis behaviors of four types of pretreated switchgrass (torrefied at 230 and 270°C, densification, and torrefaction at 270°C followed by densification) were studied at three temperatures (500, 600, 700°C) using a pyroprobe attached to a gas chromatogram mass spectroscopy (Py-GC/MS). The torrefaction of switchgrass improved its oxygen to carbon ratio and energy content. Contents of anhydrous sugars and phenols in pyrolysis products of torrefied switchgrass were higher than those in pyrolysis products of raw switchgrass. As the torrefaction temperature increased from 230 to 270°C, the contents of anhydrous sugars and phenols in pyrolysis products increased whereas content of guaiacols decreased. High pyrolysis temperature (600 and 700°C as compared to 500°C) enhanced decomposition of lignin and anhydrous sugars, leading to increase in phenols, aromatics and furans. Densification enhanced depolymerization of cellulose and hemicellulose during pyrolysis.
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