A sequential method to analyze the kinetics of biomass pyrolysis

Area of Science:

• Chemical Engineering
• Thermodynamics
• Biomass Conversion

Background:

• Biomass pyrolysis is a crucial thermochemical process for converting organic matter into valuable products.
• Accurate kinetic modeling is essential for optimizing pyrolysis reactor design and process efficiency.
• Existing kinetic models often require complex parameter determination and may not universally apply to diverse biomass components.

Purpose of the Study:

• To develop and validate a sequential two-stage kinetic analysis method for biomass pyrolysis.
• To determine the reaction order and kinetic parameters for cellulose, hemicellulose, and lignin surrogates.
• To simulate biomass pyrolysis reaction rate profiles and assess the proposed method's applicability.

Main Methods:

• A two-stage sequential kinetic analysis was employed.
• Stage one involved determining the unreacted fraction at maximum reaction rate ((1-α)(m)).
• Stage two focused on simulating reaction rate profiles using calculated kinetic parameters, with filter paper (cellulose), xylan (hemicellulose), and alkali lignin as model compounds, assuming reaction orders of 1, 2, and 3, respectively.

Main Results:

• The kinetic parameters for most biomass pyrolysis scenarios were accurately determined.
• Reaction rate profiles were effectively simulated by assuming a first-order reaction, especially for cellulose-like materials.
• The method demonstrated good applicability to the pyrolysis of filter paper, xylan, and alkali lignin.

Conclusions:

• The proposed sequential two-stage method provides a reliable approach for biomass pyrolysis kinetic analysis.
• A first-order reaction model is often sufficient for simulating the pyrolysis kinetics of key biomass components.
• This method is broadly applicable to biomass pyrolysis and similar reactions where (1-α)(m) can be reliably obtained.