Written by Trevor Lui
Edited by Angus Yip
Have you always heard how plastic bags are bad for the environment, and how you should always use a reusable bag? What if I told you that this is a lie, and that plastic bags may not be bad for the environment, but instead, can be turned into sustainable fuel.
Most plastic waste which we use (including plastic bags) end up in one of Hong Kong’s 13 landfills, however, a small percentage of plastic waste ends up in the oceans. This can cause damage to marine life, as well as extinction of some species. But with the development of research in this sector, researchers have found a way to turn plastic waste into fuel.
Pyrolysis
The process which is used to turn plastic into fuel is called pyrolysis, where plastic is heated at high temperatures, and allows for it to be separated and reused in an eco-friendly way.
(Scientists Find Way to Turn Waste Plastics into Jet Fuel-Range Hydrocarbons, 2019)
An example would be turning plastic waste into jet fuel. Plastic is made of polymeric macromolecules, an example being PVC (—(—CH2—CH(Cl)—)—), which is one of the most common types of plastics. The plastic will go through pyrolysis, which uses a catalyst, breaking down the plastic at a high temperature, and going through an upgrading process, which separates the plastic into physical activation and chemical activation. After this process, the plastic waste can be used as jet fuel.
(Vijayakumar, Sebastian, 2018)
This process is an extremely simple way to turn primary waste into fuel or other valuable chemicals,and by using this process, researchers were able to convert 90% of the plastic waste into sustainable fuel. The ideal temperature for this process would be 220°C, lower than other pyrolysis processes, but very efficient in converting plastic waste to jet fuel taking approximately one hour.
Plastic to Hydrogen
After using the process illustrated above, the combination of plastic and catalyst is left in an alkaline solution that is exposed to the sun (sunlight), breaking down the material, producing bubbles which are made of hydrogen gas.
Plastic to Diesel
Using the process above, plastic can be turned into diesel, by using the products from the above reaction, in combination with alkanes to produce diesel. By removing or adding bonds in between the different hydrocarbons, this allowed the researchers to restructure the plastic into a type of diesel which can be used to power cars or other vehicles.
Hydrothermal Processing
Researchers at Purdue University discovered another technique called hydrothermal processing, which alternatively uses water heated at high temperatures ranging from 380 to 500°C for a total of 5 hours at a high pressure. At high temperatures and pressure, the plastic is broken down by water into oil. Most plastics are created using oil, so this process helps return the plastic bags into their original state.
References
New technology converts waste plastics to jet fuel in an hour. (2021). Retrieved 19 November 2021, from https://www.sciencedaily.com/releases/2021/05/210517124937.htm
Pahl, C. (2020). Converting Plastic Waste to Fuel. Retrieved 19 November 2021, from https://www.plugandplaytechcenter.com/resources/converting-plastic-waste-fuel/
Scientists Find Way to Turn Waste Plastics into Jet Fuel-Range Hydrocarbons. (2019). Retrieved 19 November 2021, from http://www.sci-news.com/othersciences/chemistry/waste-plastics-jet-fuel-pyrolysis-07252.html
Turning plastic grocery bags into sustainable fuel. (2021). Retrieved 19 November 2021, from https://www.sciencedaily.com/releases/2021/11/211103135908.htmhttps://www.sciencedaily.com/releases/2021/11/211103135908.htm
Vijayakumar, A., & Sebastian, J. (2018). Pyrolysis process to produce fuel from different types of plastic – a review. Retrieved 19 November 2021, from https://www.researchgate.net/figure/Chemical-reaction-involved-in-pyrolysis-35_fig1_327289989
Comments