Research on the optimum carbonization process of walnut shell based on dynamic analysis.

Area of Science:

• Biomass energy
• Materials science
• Chemical engineering

Background:

• Walnut shell is a sustainable feedstock with high fixed carbon and low ash content.
• Understanding its carbonization thermodynamics is crucial for efficient conversion.
• Previous studies lack comprehensive optimization of the carbonization process.

Purpose of the Study:

• To investigate the thermodynamic parameters of walnut shell carbonization.
• To elucidate the carbonization mechanism and kinetics.
• To propose an optimal carbonization process for maximizing yield and quality.

Main Methods:

• Thermodynamic analysis of walnut shell pyrolysis.
• Experimental investigation of carbonization under varying heating rates.
• Kinetic analysis of decomposition stages (hemicellulose, cellulose, lignin).
• Process simulation and optimization using experimental data.

Main Results:

• Pyrolysis characteristic index peaks at a heating rate of 10 °C min^-1.
• Carbonization reaction intensity is highest at this optimal heating rate.
• The process involves staged decomposition with increasing activation energy.
• Optimal parameters identified: 14.8 min heating, 324.7 °C final temp, 55.5 min holding, 2 mm particle size, 69.4% carbonization rate.

Conclusions:

• Walnut shell carbonization is a multi-step process influenced by heating rate.
• Optimal conditions significantly enhance the carbonization efficiency and product characteristics.
• The proposed process provides a guideline for industrial-scale walnut shell conversion.