There’s an ever growing population of plastics that are finding their way to landfills, while the growing threat of running out of fossil fuels always seems to be just around the corner. Researchers have been studying what can be done to curb the amount of plastics being thrown away, and a different set of scientists have been studying ways to convert plastics into other useful materials. They have finally determined a potential solution for both scenarios: converting plastic waste into fuel.
The process to converting plastic waste into a useable fuel involves an advanced pyrolysis technology, which can be used to break down recyclable plastics into fuel oil and carbon black. Plastics that are based on polypropylene, polyethylene, polystyrene, ABS, pure white plastics, or plastic cables are the better choices to convert to fuel, but each will affect the transition rate that it takes to convert to fuel and carbon black.
The overall process involves a catalytic degradation of waste plastics into a fuel range of hydrocarbons such as basic fuel, diesel, kerosene, or others. The process uses a catalytic cracking process to break down the waste plastics at a very high temperature, and the resulting gases are condensed to recover the liquid fuels. The detailed plastic to fuel conversion process looks like this:
- Waste plastics are put into the pyrolysis reactor
- The reactor is then heated by burning a fuel material such as coal, or wood, or natural gas, oil. The pyrolysis reactor will be slowly heated, and when the temperature reaches around 250 degrees, the oil gas will be generated.
- The oil gas will go into a cooling system to become liquid oil. The gas can’t be liquefied under normal atmospheric pressure, requires a pressurized cooling system to create the end oil gas. Some of the resulting oil gas can be directly used in the reactor combustion system to replace the fuel material heating the reactor. This saves from burning more coal, wood, natural gas, or oil and makes the process self-heating in essence after the original heat is created.
- When the oil production is complete, the temperature of pyrolysis reactor will have dropped significantly to allow the carbon black to be removed from the reactor. That will be done at approximately 100 degrees Fahrenheit.
- The hot smoke created from transitioning plastics to oil gas and carbon black can be released to the atmosphere after being processed by an attached de-dusting system.
The pyrolysis process is safe, energy-saving, and environment friendly, and does create end products that can be used in different ways:
- Oil gas from plastic waste can be used as fuel oil in industries using boilers. The gas can be used to heat the boilers, or be used in generators to generate electricity.
- Carbon black can be used for construction bricks with clay or used as a fuel in a similar manner to oil gas.
- A portion of the oil gas can be used directly in the pyrolysis reactor as fuel, which will save energy for the whole process.
This pyrolysis method can benefit everyone. The current plastics that are being discarded to degrade in landfills have a potential second life as fuel to generate energy in manufacturing facilities. That can reduce the need for future fuel, and reduce the amount of waste plastics thrown away. In a recent article it was written that the U.S. could support up to 600 plastics-to-fuel facilities and generate nearly 39,000 jobs, resulting in nearly $9 billion in economic output from plastics-to-fuel operations. That is a goal that needs to be driven through each segment of the economy, and brought to the attention of the local governments that have the opportunity to start the process of converting waste plastics into fuel.
Matthias Poischbeg was born and raised in Hamburg, Germany. Matt moved to Everett, Wash., after finishing his bachelor’s degree in business in 1995 to work for Sea-Dog Corporation, a manufacturer, and distributor of marine and rigging hardware established in 1923.
In 1999, Matt took over the reins at Sea-Lect Plastics Corporation, a sister company of Sea-Dog and a manufacturer of plastic injection molded products with an in-house tool & die shop. Matthias Poischbeg is also a contributor to Grit Daily.