Industrial Two-Phase Olive Pomace Slurry-Derived Hydrochar Fuel for Energy Applications

Area of Science:

• Biomass energy conversion
• Sustainable fuels
• Waste-to-energy technologies

Background:

• Olive pomace (OP) is an abundant agro-industrial waste.
• Existing research has gaps regarding OP hydrochar's fuel application.
• Valorization of OP into a viable biofuel is crucial for sustainability.

Purpose of the Study:

• To optimize hydrothermal carbonization (HTC) for olive pomace (OP) hydrochar production.
• To evaluate the molecular structure, combustion performance, and fuel characteristics of OP hydrochar.
• To assess slagging-fouling risks and identify key factors for enhanced biofuel properties.

Main Methods:

• Hydrothermal carbonization (HTC) in a pressure reactor.
• Fourier-transform infrared (FTIR) and solid-state Nuclear Magnetic Resonance (NMR) spectroscopy.
• Thermogravimetric-Differential Scanning Calorimetry (TG-DSC) analysis.
• Pearson correlation analysis and empirical indices for slagging-fouling risks.

Main Results:

• Optimal HTC conditions for high heating value (32.20 MJ·Kg⁻¹) were 250 °C for 30 min.
• Optimal HTC conditions for energy yield (87.9%) were 202.7 °C for 2.0 min.
• Hydrochar exhibited aromatic structures, lower slagging-fouling risks, and improved fuel characteristics compared to raw OP.

Conclusions:

• Hydrochar derived from olive pomace is a promising biofuel candidate.
• HTC process parameters significantly influence hydrochar quality and yield.
• Enrichment of lignin and extractives, carbon densification, and reduced ash content are key for superior biofuel properties.