Treść główna


Common uses for tire pyrolysis oil

12 minutes for read

Recovered tire pyrolysis oil (TPO) is a high-value secondary product from the pyrolysis process.

The market for it will expand by a CAGR of 2.9 between 2021 to 2031. It has enormous potential as a circular, renewable feedstock and fuel for several industries. TPO can be a viable alternative to fossil-based products and help manufacturers meet their carbon and circularity goals. 

Since TPO is a relatively new product, there’s still some discussion about which conventional feedstocks and fuels the recovered tire oil can replace. However, there are many possible tire pyrolysis oil uses for this sustainable alternative. In this article, you will learn the common application and properties of TPO.

What is recovered tire pyrolysis oil?

Recovered TPO is a product of recycling end-of-life tires (ELTs) through pyrolysis. At Contec, the results from the pyrolysis process are: 40 per cent recovered tire oil, 33 per cent recovered Carbon Black, 15 per cent recovered steel, and 12 per cent recovered gas.

Tire material is manufactured to be strong and durable, and recycling ELTs is challenging. Pyrolysis manages to upcycle the materials in ELTs through a thermochemical process. Using this method, tire crumbs, produced by shredding tires, are heated at 550°C in an oxygen-free atmosphere. The complex polymers in old tires are decomposed in a series of thermal and chemical processes to give simpler compounds in the form of oils, char (Carbon Black), and gas.

Contec is one of the few companies operating a tire pyrolysis pilot plant in Europe that produces recovered TPO in Szczecin, Poland. We’ve improved the decades-old pyrolysis process through protected innovations and novel engineering to recycle 100 per cent of the ELTs received.

The high-quality recovered tire oil produced by Contec is rich in aromatic compounds, over 50 per cent, unlike most other crude fossil fuels. Since ELTs are made of natural rubber, the oil is also bio-based.

What are the properties of tire pyrolysis oil?

TPO is a heavy, dark fluid made of a blend of many hydrocarbon families with a high sulphur, nitrogen, and oxygen content.

Recovered TPO is mainly composed of hydrocarbons, including aliphatic, aromatic, and monoterpene compounds. The aliphatic compounds are dodecane and tridecane. The light aromatic compounds are single-ring benzene, toluene, ethylbenzene, and xylene, polyaromatics are naphthalene, and monoterpenes are limonene, according to Jammel 2018.

The composition and specifications of TPO, which determine the properties of recovered TPO, can vary based on the pyrolysis process and conditions, so standardisation is necessary to find industrial applications.

Analyses of recovered TPO and comparisons have shown that its composition and properties are similar to petrol and diesel.

Where is tire pyrolysis oil used?

Recovered TPO can be a circular and eco-friendly alternative to fossil-based petroleum products if its properties and composition are similar to conventional oils.

The main potential of tire pyrolysis oil uses that have been explored are fuel for engines, heating and power generation, and feedstock for producing Carbon Black and other chemicals.

Let’s look at where TPO is used in manufacturing:

1. Tire pyrolysis oil as a New Fuel

According to Han 2023, recovered TPO has a high energy content, but its sulphur content of 1 per cent by weight is more than commercial diesel, which has less than 0.05 per cent by weight of sulphur.

TPO’s low flash point makes it less safe. Therefore, it must undergo treatment and desulphurisation before use as a fuel. After treatment, TPO (44 MJ/kg) has an energy or calorific value close to commercial diesel (45 MJ/kg). Its other properties like viscosity, density, and flashpoint also become similar to diesel after treatment.

Therefore, treated recovered TPO can be blended with diesel and used as a fossil-fuel substitute for motor vehicles, diesel burners, generators, engineering machinery, etc.

TPO is derived partially from the natural rubber used to make tires. It can be considered a biogas and renewable energy source in compliance with the 2009/28/EC European directive. The TPO produced from pyrolysis also has a competitive carbon footprint compared to other first-generation biofuels.

2. Tire pyrolysis oil for Heating

Due to the recovered TPO’s high calorific value of 41-44 MJ/kg and the similarity of its properties to diesel, it can be used as a direct substitute for diesel as a heat source, using the same machinery and pipes, in industrial settings. TPO can be used for heating purposes in industries such as boiler heating, cement, steel, glass factories, etc.

3. Tire pyrolysis oil for Power Generation

Again, TPO’s high gross calorific value makes it an ideal option as a renewable biogas fuel for generating power and cutting carbon emissions. It can replace coal or natural gas, which are expensive.

TPO has the same energy/calorific value as fossil fuel oils, 25-50 per cent more than coal, and 100-200 per cent more than wood.

Most countries around the world import fossil fuels for power generation and heating. All countries use vehicles and discard ELTs, but recycling is poor in many countries. These nations could use ELTs as feedstock to produce economical TPO and cut back on fossil fuel importation.

4. Tire pyrolysis oil for Carbon Black Production

Currently, 90 to 95 per cent of virgin Carbon Black (vCB) is produced using fossil fuel-based feedstocks, rich in aromatic compounds. TPO can be a sustainable and circular feedstock that reduces reliance on fossil fuels for manufacturing vCB of medium to low-reinforcing vCBs.

The presence of high sulphur content is also not a problem and doesn’t influence the yield or the product characteristics. Producing vCB is also scalable, and using TPO as feedstock for some grades can contribute to a circular economy.

5. Tire pyrolysis oil for High-Value Chemical Production

After distillation, TPO yields three fractions, including naphtha, from which it’s possible to extract high-value components like benzene, limonene, toluene, xylene, and phenolic compounds.

According to Han 2023, these compounds are individually valuable for producing industrial commodities:

  • Limonene is used to manufacture aromatic agents and solvents.
  • Benzene is needed to make dyes, drugs, pesticides, and surfactants.
  • Xylene derivatives are used in the fibre industry and for producing polyester fibres.

What are the advantages of using recovered tire pyrolysis oil?

TPO has substantial economic and environmental benefits, largely because tire pyrolysis oil uses can be a substitute instead of virgin fossil fuels in many industries.

Some of the main benefits are:

1. TPO production is more economical than fossil fuels

As fossil fuels become scarce, extraction requires more resources and costs. In contrast, TPO is produced using abundant and economical tire waste as feedstock. Manufacturers in the European Union must pay for their waste management, and any landfilled material can be expensive.

Shredding waste tires and using them as feedstock to produce TPO lowers manufacturers’ costs and provides them with valuable, circular raw materials.

2. TPO from ELTs is more economical than fossil fuels

South Asian countries are opting to use recovered TPO, as natural gas is more expensive, and they’re seeking to reduce dependence on coal for power generation. Similarly, African countries cannot meet the demand for fuel for industries through conventional fuels and find using recovered TPO is more economically viable than increasing the import of fossil fuels.

3. TPO is more attractive than other biofuels

Interest in recovered TPO is increasing to keep up with the boost in demand for renewable energy sources. Recovered TPO can be used in existing fossil fuel facilities, making it an easy substitute. Moreover, it has more energy than ethanol and is more stable and easily transported than biodiesel.

4. TPO reduces land use changes and emissions from mining 

Replacing virgin raw materials with circular secondary tire oil will reduce the associated pollution and environmental costs of exploration, mining, and processing. Less mining also protects pristine biodiversity-rich forests from being cut down to mine more fossil fuels.

5. TPO can be produced in decentralised and small operations

When tire recycling facilities aredistributed throughout a country, they can prevent long-distance transportation of fossil-based raw materials. The shorter transport distance will also reduce the carbon footprint and pollution associated with transporting ‘new’ fossil fuels. Local production of TPO can reduce dependence on imports of fossil fuels, providing assured and uninterrupted feedstocks and fuel supplies to industries.

6. TPO reduces carbon footprint 

TPO has a lower carbon footprint than fossil fuels. Choosing TPO as the raw material for manufacturing will lower the carbon footprint of processes and products and can improve air quality through reduced pollution.

Increasing TPO applications with Contec

As industries become more circular, the opportunities that recovered TPO offers the tire, vCB, chemical, and manufacturing sectors are great. Equally, if not of greater interest, is the possibility of using TPO to generate power and run vehicles, two of the most polluting sectors with significant carbon footprints. Contec seeks to increase tire oil applications by providing a reliable source of high-quality tire oil for these industries. Find out more about Contec’s sustainable TPO.

If you liked reading this article, we recommend the following content:

Interested in working together?

Get in Touch