3 Exciting New Ways Chemical Recycling Converts Plastic Waste into a Circular Plastics Economy

Scientific Technology at its Best: Reducing the World’s Plastic WasteMechanical Recycling of Plastics

Mechanical Recycling of Plastics

You drain your bottled water and immediately toss it into a recycling bin. You know PET #1 plastic is easily recyclable, so you feel confident it won’t become waste. But how do you know that? What if others have thrown soiled plastics into the same bin, rendering the whole container contaminated? What if the waste recycling company responsible for your water bottle avoiding incineration, landfill or the Great Pacific Garbage Patch drops the ball somehow? These are important questions as we move closer to a world without the requisite raw materials to keep up with consumption.

Currently, most waste and disposal businesses employ mechanical recycling. Workers and sorting machines separate plastics from a mixed stream, which are ground, washed, dried, melted, granulated and compounded into pellets sold to clients who will reform them into recycled plastic goods. This conversion process complements the virgin plastic industry and helps reduce landfill space and global warming gases such as CO2 and methane (CH4).

But is there a better way?

Chemical Recycling of Plastics

The answer is a resounding “YES!” The chemical recycling of plastics by dissolution, conversion and depolymerization offers more than a complement to the use of virgin material. They replace the need for it altogether. Breaking down plastics into original monomers and polymers and then reconstituting them means a new product is made, not a recycled one, i.e., a used one. Sound intriguing??

How does chemical recycling of plastics work? First, we must understand how plastics are made. A very simplified chain to making finished plastic products looks like this: Fossil Resources > Feedstock > Monomers > Polymers > Plastics. Chemical recycling offers breaking into this chain at different levels. But each provides a glimpse at a circular plastics economy. Let’s take a look at three popular methods for the chemical recycling of plastics:

• Dissolution:
• Separation and sorting of plastic waste for further processing.?
• Solvents and heat are introduced, dissolving the plastic waste into the original polymers (substances made from similar molecules bonded together) and additives that formed it.
• The additives are separated from the polymers and removed, with the polymers extracted and kept.
• New additives are added to the recovered polymers, producing new recycled plastic.
• Depolymerization:
• Separation and sorting of plastic waste for further processing.?
• Combinations of chemicals, solvents and heat break down the plastic waste further than dissolution does into monomers (molecules that can be bonded to form a polymer).
• Contaminants are isolated and removed and the monomers kept.
• The monomers are fed back to the plastic chain as a secondary raw material, where they will form polymers.
• The recycled plastics formed from depolymerization are similar in quality to those from fossil resources.
• Conversion:
• Separation and sorting of plastic waste for further processing.?
• Chemicals and heat are applied in a reactor, breaking down the plastic waste into an oil (pyrolysis — oxygen absent) or gas (gasification — oxygen present).
• Contaminants are removed and the clean oil or gas is kept.
• This oil or gas, called feedstock, replicates the quality of fossil or virgin resources and is fed back into the plastics chain at the beginning, thus bringing us full circle.

Is Chemical Recycling of Plastics the Future?

This is a supercharged topic in the manufacturing industry. Everyone agrees we have a plastics problem, and the need for better plastic recycling is a hot-button issue. The truth is that chemical recycling is costlier than mechanical recycling. And the need to retool and learn new practices means new workers and higher labor costs — at least at the start.

But the benefits are genuinely exciting. Some plastics, such as polystyrene, which can’t be recycled using traditional mechanical means, can be with chemical ones. That provides a cleaner multistream of plastic waste and less need for human sorters.?

And while fewer raw materials need to be farmed for fossil resources, chemical recycling does have its detractors. Some claim that if fuels are made (naphtha, crude oils or fuels) and burned, the CO2 increase is too much of a detriment. However, this doesn’t consider the many non-fuel products that have virtually no drop-off in quality — without necessitating the tapping of new fossil resources. Others decry that chemical recycling of plastics requires a clean stream of similar types to be of any benefit, but the mechanical type requires the same clean supply.??

Ultimately, each has drawbacks. Each has benefits. Look at the food packaging industry; regulations require new materials to be used instead of the mixed granulate produced by mechanical means. Chemical recycling solves this and can produce vast quantities of food-grade packaging that passes US and EU inspection.

A Growing Problem Demands an Answer

Humans produce waste in the US, the EU or the Far East. And plastic consumption keeps growing as previously third-world countries are developing into significant world players in industry and manufacturing. That means greater energy use, disposable incomes and waste. Where do the raw materials come from to meet this demand when the earth runs dry? Recycling efforts simply aren’t keeping up.

A seamless integration of chemical recycling alongside improved mechanical recycling would be ideal. But that means the investment of money, time, training and more. And greed is a real problem nobody wants to discuss. Many business owners’ unwillingness to change stems from an age-old problem: wealth accumulation. And where there’s wealth, there’s often a desire to gain more, not spend on a future they’ll not be around for. It’s a compelling argument.

Just ask John D. Rockefeller, an American business magnate and philanthropist. He was born in 1839 and died in 1937, and in between, he owned ninety percent of this country's oil and gas industry. During the height of his enormous wealth, he was asked this question: “How much money is enough money?” He answered,

“Just a little bit more.” — John D. Rockefeller

Wrapping Up

Where does that leave us? Stuck in the middle, to be sure. Chemical recycling offers an opportunity many are seizing to reverse humans' negative impact on this planet. The ability to obtain the materials needed for our plastic consumption without tearing up the earth for fossil resources provides a glimpse at what we can do when we set our minds and wallets upon it.?

Or are we better off polishing our mechanical recycling efforts and refining them until reaching peak efficiency? The answer may lie in the middle, but chemical recycling of plastics needs to go forward for many reasons, not the least of which is the shortage of raw fossil resources. History will tell those in the future what we choose to do today.