22 April 2024

Our feedstock sourcing and processing strategy for the future of sustainable aviation fuel production

Our feedstock sourcing and processing strategy for the future of sustainable aviation fuel production

Sourcing the correct input material is critical for making Sustainable Aviation Fuel (SAF) economically and at scale. At Avioxx, our primary focus is on transforming household waste destined for incineration into SAF, but the Avioxx Process is also compatible with various other non-recyclable wastes.

Our team has assessed the use of five different waste inputs, referred to as feedstocks, on their chemical composition and availability: municipal solid waste, dense plastics, organic waste, wood and paper, and fabrics. Each feedstock presents unique advantages and drawbacks and different considerations for processing, informing our approach towards our sustainable fuel development programme.

1. Municipal solid waste

Household waste offers the greatest carbon reduction potential among the five waste streams analysed by diverting it from harmful incineration or landfill. It's abundant and lucrative to acquire in its raw form, but it has varying chemical composition and high levels of impurities.

Refuse Derived Fuel (RDF), a processed form of waste, boasts fewer impurities and better consistency, making it a more compatible feedstock. However, the pre-treated nature of RDF can inflate costs of procurement.

2. Dense non-recyclable plastics

Dense plastics are a rich source of hydrocarbons and a consistent feedstock. Removing plastic litter also yields secondary environmental benefits. However, existing robust recycling infrastructure favours recycling over conversion to valuable products like fuel. Additionally, plastics pose challenges in gasification systems as they melt before they gasify and clog the reactors. Overcoming this engineering hurdle is pivotal for progress, and the Avioxx research team are eager to tackle the challenge.

3. Organic food and farming waste

Organic material, including food and farming waste, is a readily available and low-cost input for fuel production. Airlines and regulators already consider this waste stream as a high value carbon reduction feedstock. However, a major drawback is that it requires significant drying before gasification due to its high moisture content. There are also several competing pathways within the circular economy of organic waste such as energy extraction through anaerobic digestion or composting.

4. Wood chips and paper

Wood chips and paper are another dependable and readily available feedstock, already recognised as an established alternative fuel source. They also offer high recyclability and potential for reuse. However, it is difficult to measure various sustainability aspects like carbon accounting and environmental impact. There is also high potential to reuse or recycle wood and paper. Furthermore, substantial amounts of this feedstock are required to produce desired volumes of fuel.

5. Waste fabrics

Waste fabrics are a massive problem as they are not easy to recycle and are available in large volumes from an industry facing immense criticism. Every year, an estimated 90 million tonnes of textile waste are exported and incinerated globally.

They are a low cost and consistent feedstock and generally easy to sort and process. Despite this, not all fabrics are suitable for gasification. Additionally, the declining volume of waste fabrics may not be enough to meet future fuel demands.

5 key feedstocks

After careful consideration of the pros and cons of each feedstock, we have set the following priorities:

  1. High priority: municipal solid waste
  2. Medium priority: wood & paper, fabrics
  3. Low priority: plastics, organics
Sourcing Household Municipal Waste

The UK has enough household waste, if diverted from the 57 incineration plants and more than 500 landfill sites, to meet 50% of the UKs aviation fuel demand.

Refuse derived fuel (RDF) is a form of valuable household waste that has been sorted to remove non-combustible material then shredded, dried, and baled for use in energy production. The benefits of RDF for Avioxx include the opportunity to innovate high quality bespoke pellets specifically for our system and revenue generating potential in the development of pelleted feedstock.

Our current aim is to innovate a system for RDF processing to maximize the performance of the most critical stage of our system: gasification.

High priority considerations for innovation include:

  • Physical dimensions of pellets: 6mm to 10mm in diameter.
  • Different pellet shapes and sizes will change combustion properties.
  • Making pellets burst on entry to the gasifier to increase the consistency of the spread of the fuel.
  • Caution with high plastics content since it melts and hardens, clogging up the screw feeder. Incorporation into pellets can resolve this.

Municipal solid waste is the core focus of the Avioxx waste-to-SAF process development programme. Abundant and cost-effective, it offers a potential revenue stream and the opportunity to develop innovative waste processing methods. The establishment of the system for MSW paves the way for future advancements with additional feedstocks including textiles, wood & paper, plastics, and organic waste.

If you would like to learn more about our feedstock processing strategy, are a waste supplier or broker, please get in touch at info@avioxx.com.