Advanced Chemical Recycling & Pyrolysis
What is advanced chemical recycling?
Advanced chemical recycling refers to technologies that break down plastic waste into its basic chemical building blocks. Unlike traditional recycling (which melts and remolds plastics), chemical recycling transforms plastics into gases, oils, or raw materials that can be reused to make new plastics or fuels.
What is pyrolysis?
Pyrolysis is a type of advanced chemical recycling that heats plastic waste in the absence of oxygen. This process breaks down long plastic molecules into shorter ones, resulting in products like synthetic oil, gas, and carbon char.
How does the pyrolysis process work?
- Plastic Sorting: Plastics, usually those that are hard to recycle (like films or mixed plastics), are sorted and cleaned.
- Shredding: The plastic is chopped into small pieces.
- Heating: These pieces are placed in a reactor and heated to 350–600°C without oxygen.
- Breakdown: Heat breaks down plastic into vapors.
- Condensation: The vapors are cooled to form liquid oil, waxes, and gases.
- Collection: These products can be refined into fuels or raw materials for new plastic.
- Additives in the plastic end up in the char
What kind of plastics can be processed with pyrolysis?
Pyrolysis can handle plastics that are difficult to recycle mechanically, such as:
- Plastic films and bags (e.g., LDPE, HDPE, PP and OPP)
- Multi-layer packaging
- Mixed plastic waste
- Contaminated or colored plastics
Pyrolysis is not used to process plastics like PVC or PET as they affect product quality.
What are the end products of pyrolysis?
- Pyrolysis oil: Can be refined into fuels or chemical feedstocks.
- Gas: Often used to power the pyrolysis system itself or can be refined to circular LPG.
- Char: A solid byproduct that can be used in construction or manufacturing.
Is pyrolysis environmentally friendly?
Pyrolysis can help reduce plastic waste ending up in incineration, in landfills and oceans, and it can recover valuable resources from waste. However, its environmental impact depends on:
- The source of the energy used (fossil vs renewable)
- Choice of technology
- Site configuration and emissions control during the process
- How the end products are used
Well-managed systems with modern emissions controls can minimize pollution. Recycling altogether complements efforts to reduce and reuse plastic.
Does pyrolysis compete with mechanical recycling?
Not directly. Pyrolysis is generally used for plastics that are degraded or mechanical recycling can’t handle or for which there is no sufficient demand. Ideally, recyclable plastics should still go through mechanical processes, which are more energy-efficient especially if LPG is not valorised.
Is pyrolysis widely used today?
It’s still an emerging technology. Dozens of pilot and commercial plants are operating globally, but challenges like high costs, regulatory approval, and consistent feedstock supply limit rapid expansion.
What are the challenges or concerns?
- Emissions: If not properly managed, pyrolysis can release harmful pollutants.
- Economic viability: High startup and operational costs can be a barrier.
What role can pyrolysis play in solving the plastic waste problem?
Pyrolysis isn’t a silver bullet, but it can be part of a broader solution:
- It offers a way to recover value from non-recyclable plastics.
- It can reduce incineration, landfill use and environmental pollution.
- It enables production of food grade recycled plastics.
- Combined with reduction, reuse, and mechanical recycling, it helps create a more circular economy for plastics.