A comparative analysis of product distributions and characteristics from pyrolysis of broiler manure, naturally dried broiler manure, and layer hen manure

With the continuous increase in poultry manure production, the proper management of this waste has become a significant environmental and resource management challenge. This work studied the product distributions and characteristics from pyrolysis of broiler manure (BM), naturally dried broiler manure (NM) and layer hen manure (LM) in a horizontal tube furnace in the temperature range of 300–500°C. Gas chromatography (GC), gas chromatography-mass spectrometry (GC-MS), a specific surface area analyzer and scanning electron microscopy (SEM) were performed to analysis pyrolysis products. Results indicated that BM exhibited higher pyrolysis bio-oil yield than LM or NM after pyrolysis. All pyrolysis bio-oils contained high levels of acids, among which n-Hexadecanoic acid was the most abundant component and served as a high-quality precursor compound for biodiesel production. All the three manures produced low gas yield at 500°C, yet combustible gases (referring to H₂, CO, CH₄) constituted over 30 % of the generated gas stream. At 450°C pyrolysis, LM produced biochar with a yield (66 %) and the biggest specific surface area (12.403 m²/g). Principal component analysis (PCA) further revealed that feedstock properties were the dominant factors influencing product distributions. This work highlights the potential of low-temperature pyrolysis for sustainable manure management and energy recovery, while providing insights for the directional conversion of different manures into value-added products based on their inherent properties.