Impact of Anaerobic Pyrolysis Temperature on the Formation of Volatile Hydrocarbons in Wheat Straw

TL;DR

This study examines how different pyrolysis temperatures affect the types of hydrocarbons produced from wheat straw, showing that lower temperatures yield more bio-oils while higher temperatures increase PAHs.

Contribution

The study identifies specific temperature thresholds influencing the formation of phenolic compounds and PAHs during wheat straw pyrolysis.

Findings

Phenolic compounds peak at 650 °C during wheat straw pyrolysis.

PAHs are absent below 550 °C but increase sharply above 850 °C.

Low-temperature pyrolysis favors oxygen-rich bio-oils, while higher temperatures promote aromatic condensation.

Abstract

The anaerobic thermal decomposition of plant biomass produces raw materials such as wood charcoal, wood oil, or biogas, which can be used to replace conventional fossil fuels. This enables the development of environmentally friendly alternatives to traditional fuels without the need to develop new technologies, such as engines. The aim of the study was to verify the substances produced during the anaerobic thermal decomposition process of wheat straw. Measurement was carried out by pyrolysis at eight selected temperatures between 350 °C and 1050 °C, with an increase of 100 °C. The analysis was performed on a pyrolyzer coupled to a gas chromatograph (PY/GC-MS). An ANOVA test was used to detect the significance of the results. Based on the ANOVA analysis, the distribution of compound classes in the three temperature regimes was statistically significant. Phenolic compounds reached their highest relative abundance (or relative content) at 650 °C, while PAHs (polycyclic aromatic hydrocarbons) were absent below 550 °C and increased sharply above 850 °C. The results illustrate the thermal decomposition pathway of straw biomass: low-temperature pyrolysis favors the formation of oxygen-rich bio-oils, while higher temperatures increase aromatic condensation and PAH production.

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