Six innovative steps to make aviation fuel from household wastes

Two of today’s most pressing environmental issues are waste disposal and a growing, carbon-emitting aviation industry. At Avioxx, we have the solution to help solve both these challenges through a single process – taking regular household waste and transforming it into fuel.

To understand how this can be done, we explain the six steps required to make sustainable aviation fuel (SAF) from household waste.

1. Collection

   Councils and waste management companies organise the collection of household waste in the UK. Households are asked to separate waste into paper and glass, hard plastics and metals, and food plus garden waste. These flow into recycling and recovery systems which involve further separation steps. Unseparated wastes are also collected. These contain a mixture of food, plastics, paper and card, metals, and glass. Much of the plastic waste is film and black plastic packaging, and some is comprised of a mixture of materials.

   Avioxx’s primary feedstock is the unseparated (kerbside) residual household waste, the material which do not make it into recycling bins, or which fall outside the broad specifications of the recycle categories.

2. Separation

   AI systems can be trained to identify items of waste such as PET bottles, sandwich wrappers, banana skins, etc. These data can then drive a robotic picking system to place different items onto respective conveyors. Although separated wastes command a premium over mixed wastes, the labour costs involved are a major driver of innovation and automation in this area.

   The further separation of wastes, such as the different types of plastics, is needed because these different materials can follow different routes to their reuse, due to varying characteristics. For example, PET does not perform well in gasifiers and PVC emits toxic and corrosive chlorides.

3. Pre-processing

   There is a preferred processing route for each of the separated materials according to their properties and their level and type of contamination. This is a rapidly developing field and offers opportunities for scientific endeavour. In most cases, the pre-preparation of waste streams is needed. This is likely to involve shredding, grinding or crushing to achieve a standard particle size for ease of handling and high surface contact area.

4. Processing – Breakdown

   Different process routes exist for different materials of different purities. Mechanical processing such as remoulding, re-extrusion and physical reforming accounts for a high proportion of waste, but generally speaking, the chemical process route is necessary. This usually has two phases: the breaking down of the molecules and the building up of new ones.

   The Avioxx process uses oxygen to break down difficult-to-react materials by partial oxidation or gasification. The carbon-rich materials are preferentially converted to carbon monoxide and hydrogen, referred to as “syngas”. Other products generated, including chars, tars, liquors, carbon dioxide, methane and water, must be separated out before proceeding.

5. Processing – Re-building

   The breakdown products are then either used to reconstruct the original polymers or to create other products. In the Avioxx process, the syngas is polymerised over an iron or cobalt catalyst to form paraffins, some of which conform to the specification for aviation fuel. In this step, also known as the Fischer-Tropsch process, diesel and gasoline by-products are also formed.

6. Refining and distribution

   The specifications for Jet A-1 fuel and SAF are tight and further refinement and upgrading of the product is needed to produce high-quality fuel. Once refined through processes such as hydrotreatment, the pure SAF can be delivered to airlines, jet owners and other customers who want to fly green.

At Avioxx, we are driving the circular economy forward with our novel technology. To learn more about the Avioxx Process, please get in touch at info@avioxx.com