Vacuum pyrolysis of waste tires with basic additives

Area of Science:

• Chemical Engineering
• Materials Science

Background:

• Waste tires pose environmental challenges.
• Pyrolysis offers a method for waste tire valorization.

Purpose of the Study:

• To investigate the impact of temperature and basic additives (Na2CO3, NaOH) on waste tire pyrolysis.
• To optimize pyrolysis conditions for maximizing pyrolysis oil yield and dl-limonene content.

Main Methods:

• Waste tire granules were pyrolyzed under vacuum conditions (3.5-10 kPa).
• The effects of varying temperatures (450-600°C) and the addition of Na2CO3 and NaOH were studied.
• Pyrolysis oil composition, particularly dl-limonene content, was analyzed.

Main Results:

• Pyrolysis oil yield peaked between 450-600°C, with or without additives.
• NaOH addition significantly enhanced pyrolysis oil yield, reaching 50 wt% at 480°C with 3 wt% NaOH.
• Maximal dl-limonene content in pyrolysis oil was 12.39 wt% with basic additives.
• Na2CO3 addition did not improve pyrolysis outcomes.
• Pyrolysis gas composition was primarily H2, CO, CH4, CO2, C2H4, and C2H6.
• Pyrolytic char exhibited a surface area similar to carbon black but with high ash content (>11.5 wt%).

Conclusions:

• Sodium hydroxide is an effective catalyst for enhancing waste tire pyrolysis oil yield and dl-limonene production.
• Temperature plays a crucial role in optimizing pyrolysis oil yield, with an optimal range identified.
• The study highlights the potential of NaOH-assisted pyrolysis for producing valuable chemicals from waste tires.