Challenges in Kinetic Parameter Determination for Wheat Straw Pyrolysis

• Published in: Energies (Basel) Vol. 15; no. 19; p. 7240
• Main Authors: Fonseca, Frederico G., Anca-Couce, Andrés, Funke, Axel, Dahmen, Nicolaus
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.10.2022
• Subjects: Beech; Biodegradation; Biological products; Biomass; Biomass energy; Cellulose; Curve fitting; DDTG; Decomposition; Errors; Hardwoods; Hemicellulose; Inflection points; isoconversional; Kinetics; Lignin; Lignocellulose; Methods; Particle size; Potassium; Pyrolysis; Raw materials; reaction network; Straw; Thermogravimetric analysis; Wheat; Wheat straw; Germany
• ISSN: 1996-1073; 1996-1073
• DOI: 10.3390/en15197240

Wheat straw is a renewable agricultural by-product that is currently underutilized in the production of bioenergy and bioproducts due to its high ash content, as well as high transport costs due to its low volumetric energy density. The thermogravimetric analysis of this material produces derivative curves with a single broad peak, making it difficult to identify the three conventional pseudo-components (cellulose, hemicellulose, and lignin), which is resolved using the second derivative to determine inflection points. Model-fitting methods and isoconversional methods were applied to determine the degradation kinetics of wheat straw at two different particle sizes, as well as that of a reference feedstock (beech wood), and the obtained values were used to divide the degradation curves to be compared to the experimental data. Seven different pyrolysis reaction networks from the literature were given a similar treatment to determine which provides the best estimation of the actual pyrolysis process for the case of the feedstocks under study. The impact of the potassium content in the feedstock was considered by comparing the original pathway with a modification dependent on the experimental potassium content and an estimated optimum value.