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As the world increasingly looks for ways to reduce its reliance on fossil fuels, advanced recycling technologies offer a potential solution. Among these is "pyrolysis plastic recycling", which uses heat to break down plastic into fuel oil and other products. This page provides an overview of pyrolysis and other advanced recycling methods, as well as solvent extraction and depolymerization.
Plastic recycling is the process of recovering scrap or waste plastic and reprocessing it into new products. Since the vast majority of plastic is not biodegradable, recycling is a vital part of reducing the amount of plastic in landfills and the ocean.
Recycling plants use many methods for recycling plastic, but the most common is called mechanical recycling. In mechanical recycling, the plastic is shredded into very small pieces and then heated until it melts. The molten plastic is then poured into molds to create new products.
Globally, only 9% of plastic waste is recycled with the majority of it ending up in a landfill, incinerated or leaking into the environment. In 2019, global plastic waste generation more than doubled from 2,000 to 353 million tonnes. It is forecasted that this figure will increase to 40% by the year 2030.
To combat this, governments around the world are taking steps to transition from a linear to a circular economy model. Plastic recycling plays a key role that enables this transition. The United States EPA launched the National Recycling Goal to reach a 50% recycling rate by 2030. The European Union Packaging Directives targets a 55% recycling rate for plastic packaging.
It is estimated that there will be more plastic waste than fish in the world's oceans by 2050. This shocking statistic emphasizes the importance of recycling plastic waste and finding innovative ways to reuse this material.
The conventional method used in the plastics industry is mechanical recycling. This process uses machines to grind, separate, dry and compound plastic pieces. Its major limitation is that it cannot optimally recycle the variety of mixed plastic waste streams used today. Mechanical recycling is also not efficient at controlling contamination from various plastics sources.
Mechanical recycling is limited to thermoplastics material that can be re-melted and remolded into new products. During the process, plastic waste is sorted, washed, shredded, heated, extruded. This matter is pelletized into recycled raw materials without modifying the structure of the plastic material. This process has a few limitations as it requires the plastic waste to be as clean and pure as possible to minimize risk of contamination.
Additionally, color may vary by batch as the original waste plastic pigmentation is retained and not removed by the process. Furthermore, waste plastic cannot be mechanically recycled indefinitely as the material properties of the plastics become degraded with each recycling cycle.
Currently, mechanical recycling is the main driving reason for the low recycling rate of plastics. However, the emerging development of Advanced Recycling technology is set to address these limitations. It aims to increase the plastic waste recycling rate and enable transition to a circular economy model.
A circular economy is an economic model that is restorative and regenerative by design. It is a closed-loop system in which waste is eliminated, as much as possible. In a circular economy, resources are kept in use for as long as possible, and waste is managed so that it has the least possible negative impact on the environment.
The goal is to "reduce, reuse, recycle" and thereby keep products and materials in the economy for as long as possible. Any new innovative recycling technologies will play a key part in paving the way towards a circular economy model.
Advanced recycling combines mechanical and chemical recycling methods in the process of breaking down materials into raw commodities for reuse. This is done through a variety of methods such as thermal decomposition, chemical dissolution, or mechanical separation. The most effective form of advanced recycling is pyrolysis plastics recycling.
Advanced Recycling uses processes such as pyrolysis to break down plastic waste at a molecular level, converting it into a diverse range of products. These include industrial waxes and fuels. Pyrolysis can also convert plastic waste back into its original building blocks. These can be used as feedstock for new chemical and plastic products.
Pyrolysis is the leading method and core technology utilized in advanced plastic recycling. It involves decomposition of plastic waste through heat typically at about 500°C in the absence of oxygen. This process conditions and vaporizes plastic waste in the pyrolysis reactor. It is then condensed to produce pyrolysis oil along with fuel gas and char (carbon black), and hydrocarbons.
In a nutshell, pyrolysis produces far less waste than traditional recycling methods while generating reusable products. Pyrolysis oil is the main product generated from this process and it is used as feedstock to produce new plastic materials and synthetic chemicals.
Accounting for about 25% of the output, the other two products generated by pyrolysis are fuel gas and char. Fuel gas is used to heat or power the pyrolysis plant or reactor and char is used in asphalt production or landfilled.
The pyrolysis process is efficient in handling and recycling polyethylene, polypropylene and polystyrene types of plastic waste. These difficult to recycle plastics are commonly used in consumer packaging like milk bottles, shrink wrap, and microwavable food containers. These disposables make up most of the plastic waste generated.
When combined with conventional mechanical recycling, advanced recycling methods like plastic pyrolysis significantly increase the types of plastic waste that can be recycled. Advanced recycling methods can also help in creating a circular economy where plastic waste can be continuously used as raw material.
The recycling industry is always looking for better and more efficient ways to recycle materials. Chemical methods of recycling post-consumer plastics into new products break down the polymers into their component molecules. These are then recombined to form new plastics. There are two primary methods of chemical recycling: solvent extraction and depolymerization.
Below are some of leading plastic recycling methods that are currently being developed:
The solvent extraction process is a process that uses solvents to break down the plastic into smaller pieces. The smaller pieces can then be recycled into new products. The solvent extraction process is used to recycle items such as plastic bottles, plastic bags, and plastic containers.
This process uses solvent to dissolve plastic waste. It filters out impurities and reconstitutes the plastic polymer properties to produce materials nearly equivalent to virgin plastic.
This process involves breaking down plastic waste material into its building blocks or monomers. These are then purified and repolymerized to produce new plastic materials with properties indistinguishable from those of the original. Additionally, this process does not degrade the plastic material properties and allows plastic to be recycled continuously.
Milton Roy products are utilized by the petrochemical and chemical industries to ensure accuracy in the delivery of various critical chemicals. These include corrosion inhibitors, emulsion breakers, oxygen scavengers and catalysts.
Our API 675 compliant pumps have been designed for steady-state accuracy of ±1%. They are offered with multiple liquid end configurations including critical service diaphragms to handle the various applications used in Advanced Recycling.
Standing by our proven products, Milton Roy’s global team of experts and channel partners are always ready to support your transition to a circular economy.