Chemical Recycling Recycling

Mechanical vs Chemical Recycling

What is the difference between mechanical and chemical recycling? This is a free article

Basic Stats

  • Global annual plastic waste is 220 million tons.
  • 90 million tons is littered
  • 70 million tons is landfilled
  • 30 million tons is incinerated (energy recovery)
  • 30 million ton is recycled

Definitions

Chemical recycling will split the polymer chains (the molecular structure) and provide crude oil, naphtha or fuels.

Mechanical recycling keeps the molecular structure. It mechanically crushes the plastic and remelt it into granules that can be used to make new products.

Differences

  • Sorting

Mechanical recycling needs uncontaminated waste streams. Chemical recycling doesn’t require thorough sorting, it can recycle most plastics altogether.

  • Reclamation (washing, grinding, peletizing)

Plastics are not infinitely mechanically recyclable; between 3 and 7 times for most plastics. Chemical recycling makes plastic infinitely recyclable.

  • Reprocessing

Mechanical recycling is mostly “down cycling”; most plastic packaging are down cycled into other applications than their initial application. Chemical recycling will convert plastic waste into a new virgin-like plastic feedstock; enabling “re-cycling” and even “up-cycling”.

  • Infrastructure & production

Mechanical recycling represents more than 99, 9% of the infrastructure and business. Chemical recycling is a minuscule part; it doesn’t exist at large industrial scale; only test projects etc. It cost around € 200 million to build a chemical recycling plant.

  • Hard to recycle & flexible packaging

Chemical recycling is the solution to plastic waste that is hard (expensive) to recycle mechanically.

  • Energy Intensive

Mechanical recycling is less energy intensive than chemical recycling. Chemical recycling needs more energy and produces more CO2 emissions.

  • Toxicity

Mechanical recycling shreds plastic waste and doesn’t’ use toxic chemicals. Chemical recycling needs toxic chemicals (acids and solvents) to dissolve the plastics. The by-products and waste of the chemical recycling process will be an environmental hazard.

  • Investment

Mechanical recycling is bankrupt and not economically viable, nobody wants to invest in this sector anymore. Chemical recycling is the new El Dorado, the new promised land. Many companies are ready to make investments.

  • Profit margin

Mechanical recycling is very expensive, the end product (recycled plastic) is very expensive compared to virgin plastic. It’s claimed that chemical recycling will produce cheaper recycled plastic.

Back to reality

  • Does it work?

Mechanical recycling has proven to work operationally but not economically. Chemical recycling hasn’t proven to be working on a large industrial scale yet; and nobody knows if it will. There’s a difference between lab test and real life conditions. Many assumptions regarding chemical recycling may turn out to be wrong. For instance; plastic may turn out not to be infinitely chemically recyclable.

  • Waste Stream Contamination

Contaminated waste streams may eventually cause a serious operational problem for chemical recycling. It could become necessary to go for batch production instead of continuous production to control quality of the end product.

  • Recyclable Plastics

Mechanical recycling requires recyclable plastics. Chemical recycling claims to be able to recycle almost any plastics; it may encourage the marketing of non-mechanically recyclable plastics.

  • End Product

Chemical recycling will not produce virgin like feedstock; it will produce some kind of slime. Some say that chemical recycling is nothing more than turning plastic waste into fuel. Is it worth to convert plastic waste into fuel if we’re going to burn it afterwards? Why not incinerate the plastic waste in the first place?

  • The Problem of Recycled Content

Mechanically recycled plastic waste is not a clean product like virgin plastic. It’s not as aesthetically or visually attractive. Compare recycled pellets and virgin pellets and you will understand the problem: it’s not easy to find clients for recycled plastics. The applications are also technically limited. Chemical recycling may face the same problems.

  • Food Grade

Food packaging requires food grade plastics and not all recycled plastics fulfil those requirements. It won’t be easy to make food grade chemically recycled content.

  • Valorisation

In a circular approach we try to valorise waste. Waste valorisation has become an end on itself. We may have to distinguish between “economic” and “environmental” valorisation. Economic valorisation may just be an attempt to make profit without any environmental gain

%d bloggers like this: