In pyrolysis, material is heated without oxygen, typically to 400–600 °C. Nothing burns: long polymer chains crack into shorter hydrocarbons, and their vapours are cooled until they condense. The result is pyrolysis oil, the main product of plastics pyrolysis and one of three outputs alongside gas and carbon.
How much oil, and from what
With plastics, oil makes up 63% of the input mass on average, with gas at 34% and carbon at 3%. Tyres give a broader mix: 36% oil, 23% gas, 34% carbon and 7% steel. These are average mass balances for the industrial line; actual figures depend on what goes in.
So tyres yield less oil but more carbon, which returns as recovered carbon black for rubber and pigments, while the steel cord goes to steelworks.
Polyolefins and polystyrene yield the most oil, meaning PE, PP and PS from films, packaging and cups. PET and PVC contain oxygen and chlorine, which lower oil quality, so they are processed only in small shares or separated out beforehand.
The industrial line runs on a CHP (combined heat and power) unit fuelled by its own pyrolysis gas. It does not need to burn any oil to keep going, so all of the oil is available for sale.
A heating value close to diesel
Pyrolysis oil has a lower heating value of about 39 MJ/kg, compared with about 43 MJ/kg for diesel. In energy terms, it sits close to conventional liquid fuels.
It is not diesel, though. Pyrolysis oil is a mixture of hydrocarbons of different chain lengths, and its composition mirrors that of the input. Its uses are therefore industrial: in petrochemicals and energy production, where its properties can be managed.
Feedstock for new plastics
From a circular economy point of view, the most logical destination for the oil is the industry that made the plastic in the first place. Petrochemical plants crack it into monomers, which are then used to make new plastics. This is known as chemical or feedstock recycling: the plastic does not come back as shredded flakes, but via the molecules it is made from. This way, mixed and contaminated plastics that mechanical recycling cannot accept also find their way back into the loop.
Petrochemical buyers do need consistent quality, though. Each sets its own specification for the oil, and the more stable the input, the easier that specification is to meet. Our article on chemical recycling of plastics looks at this route in more detail.
According to the technology manufacturer, pyrolysis oil has up to a 40% lower carbon footprint than the same feedstock made from crude oil. For buyers working to cut emissions across their supply chain, that can be a significant point.
Fuel for boilers and CHP units
The second route is energy. The oil can fuel industrial boilers or CHP units that turn it into electricity and heat. It suits sites that already burn another liquid fuel oil.
This route is technically simpler, but the material is burned and does not return to the loop. Which route to choose depends on the oil's quality and on the buyers within reach.
Light and heavy fractions
The compact module can split the oil into light and heavy fuel oil. Each fraction can then be offered to a buyer whose equipment suits it, which widens the pool of potential customers.
REACH: a product, not waste
To be sold as a product, the oil must be registered under REACH, the EU regulation on chemicals. A registered product goes to market like any other commodity. Without registration, it would still have to be handled as waste, which sharply narrows the range of buyers.
The same applies to the carbon. Registration is part of project preparation, just like the permits covered in our article on permits for a pyrolysis plant.
Offtake at a contracted price
You can sell the oil yourself if you have buyers. Or you can use our offtake service: we buy the oil, gas and carbon from you at a price fixed in the contract, with collection included. You do not have to look for customers, and a price known in advance makes planning easier.
The price depends mainly on the quality and quantity of the oil, and so on what goes into the reactor. That is why we discuss it on the basis of your sample analysis in the feasibility study.
Our yield calculator shows how much oil your waste could produce.