Imagine a world where post-consumer plastic did not have to be placed in a landfill or incinerated. Imagine if all the negative environmental impacts associated with landfilling and incineration, such as contamination from leaching, ingestion of microplastics, and increased carbon emissions, could be virtually eliminated…forever.
Additionally, wouldn’t it be a better planet if the amount of fossil fuels needed to supply the world with plastics were also reduced? This type of future is possible. In fact, we are now in the early stages of plastic manufacturing technology that will soon take us to an even better, cleaner, and healthier future for the environment.
Mechanical Recycling has Dominated
Until recently, the only way to recycle post-consumer waste plastic and reuse it to make new plastic was through the process of Mechanical Recycling. In this process, plastic waste is sorted, washed, shredded, and heated back into resin pellets, with the actual molecular structure remaining intact. Mechanical Recycling has limitations because it requires a raw material that is as clean and pure as possible.
Color may vary by batch because the original plastic pigmentation is not removed from the plastic waste. In addition, plastic cannot be mechanically recycled indefinitely, and the process does not ensure that the resulting resin will perform the same as virgin resin. Mechanically recycled material also does not guarantee that the resulting resin is free from foreign materials or other contaminants. Plastic resin produced from this method does reduce the amount of plastic waste to be incinerated or that ends up in landfills; however, it is not considered virgin.
Fossil Fuels Drive Plastic Production
In today’s world, fossil fuels, specifically petroleum and natural gas, are refined to create the primary feedstocks for plastic production. Feedstocks are the specific chemical ingredients that go into the process, and are what get converted into plastics via chemical reactions at the plastic manufacturing plant. Ethane, obtained from natural gas, or Naphtha, obtained from crude oil, are processed into ethylene. Ethylene is a small, two-carbon molecule which is the primary hydrocarbon feedstock for making polyethylene plastic.
Plastics are made of polymers, which are molecules that contain many repeating carbon units. These long chain molecules are arranged in formations that give plastics many of the qualities that make it so versatile. Flexibility, malleability, and strength are examples of the versatile qualities that result from plastic’s chemical structure.
To make these polymers, and ultimately plastic itself, the refinement process first subjects the ethane or naphtha to “cracking”, a heat-intensive process which produces the ethylene. The process continues as the ethylene is subjected to chemical reactions which grow the number of carbon atoms each molecule possesses until the correct length polymer is formed. Plastics made from fossil feedstocks are often called synthetic plastics.
There are also bioplastics made from ethanol feedstock derived from sustainable crops, such as corn or sugarcane. This bioplastic is chemically and physically identical to petroleum-based plastic. The feedstock both sources supply produce the exact same ethylene molecules, which then create the same virgin plastic. However, because the bioplastic is made from sustainable materials, we can decrease the carbon footprint by using plastics generated from sustainable sources.
A New Way to Recycle Plastics
Advanced Recycling is a game-changing process for sustainable packaging. In this process, post-consumer plastic waste is used along with several other feedstock sources to generate identical ethylene molecules. The ethylene molecules are then processed into new batches of your current specified virgin resin. Essentially, virgin resin can now be made by using molecules derived from post-consumer plastic waste.
One of the key benefits of Advanced Recycling is that it offers a solution to transform difficult-to-recycle plastic waste into molecular feedstocks that can be used to create virgin plastics. Those plastics include polyethylene, polypropylene, polystyrene, PET, and more.
Advanced Recycling creates ethylene molecules by transforming post-consumer plastic waste into a pyrolysis oil feedstock. Ethylene molecules obtained from multiple feedstocks are mixed together to create the final virgin plastic resin. The ethylene created through this process is indistinguishable from fossil or bio-based ethylene, since it has the exact same molecular composition (four hydrogen atoms bound to a pair of carbon atoms). Similarly, the polyethylene that can be produced from these molecules is also identical to virgin resin created through fossil or bio-based ethylene.
There are major differences between Advanced Recycling and Mechanical Recycling. Mechanical Recycling is a downward spiral. First, plastic degrades over time due to ultraviolet light and other environmental conditions. Secondly, as plastic is ground and melted during Mechanical Recycling, the polymer chains are partially broken down. Both of these factors reduce the plastics’ tensile strength and viscosity, making it more difficult to process. This lower grade plastic can only be recycled a limited number of times before its altered physical properties make it unusable for plastic product containers. At some point, plastic that is mechanically recycled will end up in a landfill or be incinerated.
On the other hand, Advanced Recycling is an infinite loop. Plastic recycled this way can be processed over and over again without any reduction in physical properties. This moves us to a Circular Economy, where we can continuously use plastic waste as raw material for new plastic containers.
The Pyrolysis Process is the Key to Advanced Recycling
One of the more common and commercial technologies of Advanced Recycling is “pyrolysis” – a particularly efficient way to recycle polyethylene, polypropylene and polystyrene. The pyrolysis process is key to obtaining ethylene molecules from post-consumer plastic waste. Post-consumer plastic waste and bio-based materials are heated in a non-combustible oxygen-free pyrolysis process. This creates pyrolysis oil.
When feedstocks such as plastic waste are heated without oxygen, they do not burn. Instead, they break down into a variety of simpler hydrocarbons. Controlling the temperature and pressure affects the mix of the resulting hydrocarbons. This mixture is known as “pyrolysis oil”, a liquid substance that is a complex blend of molecules which can be further upgraded to create the ethylene needed for plastic production.
Pyrolysis is not a new technology. Because of the tremendous potential to create an absolute circular recycling model, companies have begun investing in building the infrastructure to support large scale pyrolysis production. Pyrolysis reactors are coming on-line with plans to create billions of pounds of plastic within the next 5 to 10 years. Pyrolysis oil offers us a pathway to a sustainable solution that could potentially eliminate plastic waste from the environment. But we are only in the beginning stages of this journey.
Summarizing the Processes
The graphic summarizes the plastic production processes which support polyethylene production discussed above.
- The traditional pathway to create plastic resin using the customary fossil fuel feedstocks, such as petroleum and natural gas, as the source for the ethylene needed to create plastic.
- Bio-based sustainable resources (sugarcane or corn), can be grown for use as a feedstock for plastic resin production.
- Advanced Recycling is where post-consumer plastic waste is used along with several other feedstock sources to generate identical ethylene molecules into a pyrolysis oil feedstock.
- Post-consumer plastic waste can be sorted, washed, cleaned, ground, and heated to produce a mechanically recycled resin that can be reprocessed a limited number of times.
Keeping plastic waste out of landfills and incinerators, along with eliminating the need for fossil fuels as feedstocks for plastic production, are all within reach with Advanced Recycling.
Mass Balancing For Feedstock Accounting
Currently, production of virgin polyethylene resin can use fossil fuels, bio-based materials, or pyrolysis oil feedstocks. Each batch of polyethylene can vary in the amount of ethylene molecules derived from these sources. At this time, the vast majority of polyethylene resin produced is from 100% fossil fuel feedstocks. However, there are a limited number of resins made from 100% bio-based materials on the market, but quantities are low. Since plastic will be made from multiple feedstocks, the feedstock content will be managed by an accounting technique known as Mass Balancing.
Mass Balancing has been used for years in the energy sector to account for wind, water, and fossil feedstocks for energy production. Similarly, the Mass Balancing method for polyethylene resin is a certification trail that allows companies to accurately and consistently claim how much of the resin content is bio-based or recycled-based. This system allows Drug Plastics to purchase certificates indicating a specific amount of pounds that are being supported. Customers can purchase certificates for the number of pounds they choose to support. In addition, customers can claim the use of recycled material for designated products up to the amount of certificate pounds that were purchased.
Since the resulting resin is identical to virgin resin, Mass Balancing is needed to identify how much of the content comes from each source. The eventual goal is that the majority of molecules, and the resultant plastic resins, are sustainably created through this Circular Economy.
Several organizations are leading the effort to certify the amount of recycled and bio-based materials in the Mass Balancing model. The ISCC System GmbH in Cologne, Germany, one organization that is overseeing widespread global adoption. For each batch of resin that is sold, the purchaser of the resin receives both a certificate of assurance and credits. The certificate that contains the circular or recycled content claim is called the Sustainability Declaration. The credits, derived from Mass Balancing, communicate how many pounds or metric tons of the specific batch were produced using recycled or bio-based materials. This system serves the dual purpose of assuring resin producers provide accurate information, and delivering information to consumers to validate the quantity of recycled and bio-based materials. You can learn more about the International Sustainability and Carbon Certification at www.iscc-system.org.
We Can Help
Interested in finding out more about Advanced Recycling and how Drug Plastics is working to implement Mass Balancing for our customers? We’ll show you how this new technology can positively impact the environment, lessen our reliance on fossil fuels, and reduce the amount of plastic waste that goes into landfills around the world. Contact us to speak with a knowledgeable team member or call 610-367-5000 to speak with someone immediately.