8.3 Petrochemicals: Recycling Plastics

Author: Payton Archer

ABSTRACT: Petrochemicals are in everything; from the dyes in our clothes, to the electronics we use, and the furniture we sit on. So, what exactly are they and how do they impact our recycling plastics?

MAIN:

The process to make petrochemicals, requires energy in huge amounts and involves a distillation phase, in which hydrocarbons are separated from the fossil fuels. The separated hydrocarbons are then sent to facilities called “crackers”. These facilities convert them into useful chemicals, known as “feedstock” (Donev, 2020). Chemical feedstock refers to any type of unprocessed material used in a manufacturing process as a base material to be transformed into another end product. The primary class of petrochemical feedstock includes (Donev, 2020):

  • Olefins (ethylene, propylene, and butadiene)
  • Aromatics (benzene, toluene, and xylenes)
  • Methanol

Basic petrochemicals such as these are the basis of many products, including plastic, paper, fibres, adhesives, and detergents. 99% of all plastics are created from oil and natural gas, with most being manufactured using naphtha feedstock. Naphtha is created during the distillation process. It is one of the most important of all the petrochemicals simply because it is used in the production of plastics (Donev, 2020).

Mechanical vs. Chemical Recycling

Traditional recycling was done mechanically by shredding and heating up plastics into pellets that can be used to make new things. Though this initially seemed great, it has been found that most of these plastics can only be recycled about 6 times, until they are no longer reusable (Tullo, 2021). In 2015, the US recycled only 9.1% of the 31 million tons of plastics that consumers threw out, according to the Environmental Protection Agency. The vast majority ended up in either landfills or incinerators. In contrast, two-thirds of paper, a third of metals, and a quarter of glass were recycled that year (Tullo, 2021).

Figure 1: The majority of plastics waste currently goes to landfills and incineration. Source: McKinsey & Company

A big issue is that although plastics are long-lived products that could be used for many decades, they are used typically in single-use items that are thrown out within a year. Once in a landfill, they will remain there for centuries. These plastics accumulate in landfills and in the ocean. Currently, there is a large mass of accumulating garbage in the ocean, composed mostly of plastics, known as the Great Pacific Garbage Patch. One common misconception is that large plastic pieces are floating around in this area, when in reality the majority of the waste has broken down into nurdles, which leaves the water looking cloudy and murky. This patch is estimated to be twice the area of Alberta (Donev et al, 2020).

Figure 2: A map showing the two garbage patches in the Pacific Ocean which combine to create the Great Pacific Garbage Patch. Source: Energy Education

Though, a promising solution is on the horizon. A way in which uses petrochemicals to chemically recycle these plastics. Today, petrochemical companies, researchers and scientists around the globe are exploring ways to recycle plastic into fuels, petrochemical feedstocks, or even their original building blocks (called monomers), through a process known as chemical recycling (Communications, 2019) In one type of chemical recycling, plastics, are transformed into something called naphtha, a petrochemical “feedstock” used to make monomers. Then these recycled monomers can be transformed back into polymers. (Communications, 2019). This significantly reduces the amount of plastic waste sent to landfills and the degradation process involved with mechanical recycling.

Figure 3: How plastics waste could feed into an integrated petrochemicals complex. Source: McKinsey & Company

RESOURCES:

Communications, A., 2019. Petrochemical makers are innovating to enable more plastics recycling. [online] Afpm.org. Retrieved from https://www.afpm.org/newsroom/blog/petrochemical-makers-are-innovating-enable-more-plastics-recycling [Accessed 3 March 2021].

Hundertmark, T., McNally, C., Simons, T. and Vanthournout, H., 2018. No time to waste: What plastics recycling could offer. [online] McKinsey & Company. Available at: https://www.mckinsey.com/industries/chemicals/our-insights/no-time-to-waste-what-plastics-recycling-could-offer [Accessed 24 February 2021].

J.M.K.C. Donev et al. (2020). Energy Education – Petrochemical [Online]. Retrieved from https://energyeducation.ca/encyclopedia/Petrochemical [Accessed: Feb 19, 2021].

 Tullo, A., 2021. Plastic has a problem; is chemical recycling the solution?. [online] Cen.acs.org. Available at: https://cen.acs.org/articles/97/i39/Plastic-problem-chemical-recycling-solution.html [Accessed 22 February 2021].

BIOGRAPHY

Payton is a second year New Media undergraduate student at Ryerson University. She has always valued the environment and hopes to build a future that is completely sustainable. She has worked mostly in retail and food service and has seen first-hand how big corporations disregard the importance of environmentally friendly practices in hopes to make more money. She hopes to graduate in two years and start her own environmentally sustainable business while also practicing gardening in an effort to preserve the environment.

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