Formation of liquid and solid products from liquid phase pyrolysis

Area of Science:

• Biomass conversion
• Thermochemical processing
• Lignocellulosic chemistry

Background:

• Improving the carbon-to-oxygen (C:O) ratio in biomass is crucial for efficient biofuel production.
• Lignocellulosic biomass presents challenges due to its complex structure, particularly the lignin component.
• Existing pyrolysis methods often degrade lignin, limiting C:O ratio improvement.

Purpose of the Study:

• To enhance the C:O ratio in biomass through liquid phase pyrolysis.
• To preserve the lignin macrostructure during the liquefaction of lignocellulosic feed.
• To prepare biomass for subsequent upgrading processes such as hydrogenation and deoxygenation.

Main Methods:

• Liquid phase pyrolysis was conducted using a non-aqueous liquid phase heat carrier.
• The process was performed in a semi-batch reactor under isothermal conditions at 350°C.
• Rapid quenching was employed to halt reactions and study solid intermediate formation, enabling observation of liquid and solid product generation.

Main Results:

• Infrared spectroscopy and elemental analysis were used to analyze biomass transformation into biochar.
• A stable lignin structure was confirmed throughout the entire process.
• The lignin framework in wood remained largely intact, while carbohydrates were significantly pyrolyzed at 350°C.

Conclusions:

• Liquid phase pyrolysis at 350°C effectively preserves the lignin macrostructure in lignocellulosic biomass.
• This method facilitates the liquefaction of biomass and improves its C:O ratio.
• The preserved lignin structure is advantageous for subsequent upgrading steps, leading to more efficient biofuel production.