The National Energy Technology Laboratory (NETL), a U.S. Department of Energy laboratory with facilities in Oregon, West Virginia, and Pennsylvania, is testing a new way to deal with the rising tide of plastic waste.
Their study focuses on combining plastics with coal and biomass in a process called steam gasification.
This approach can create hydrogen-rich syngas, a versatile fuel and chemical building block that may help solve energy and environmental problems.
The work is led by Ping Wang and her NETL team, who believe this method could provide a more efficient and affordable pathway to recover energy from discarded plastics.
Why are plastics so difficult to reuse
Plastics such as low-density polyethylene (LDPE) and high-density polyethylene (HDPE) make up most of today’s discarded plastic waste.
LDPE is commonly used in bags, containers, and packaging, while HDPE is found in bottles, pipes, and food containers. Their widespread use in single-use products means they accumulate rapidly, with limited recycling options.
“Plastic waste management is increasingly becoming a global concern and must be urgently addressed,” Wang said.
“According to one estimate, 6.3 billion tons of plastic waste were generated in the last six decades, out of which, 60% accumulated in the landfills and natural environment. The inadequate management of waste plastic in landfills causes serious environmental problems, such as groundwater contamination and sanitary-related issues.”
Plastics pose major challenges in gasification because of their low melting points, which cause particles to stick together, clogging reactors. They also require energy-intensive shredding and grinding to achieve uniform particle sizes.
On top of that, plastics produce large amounts of tar when heated, reducing process efficiency.
Using coal waste to improve gasification
The NETL team believes co-gasifying plastics with coal refuse can solve many problems. Coal waste contains alkali and alkaline earth metals that act as natural catalysts.
These minerals can promote char gasification and reduce tar formation, making the process smoother and more efficient. Researchers say they can fine-tune the process by blending plastics with coal and biomass to produce better-quality syngas.
“Co-gasification of plastics with other feedstocks, such as coal and biomass, also offers a flexible approach that allows feedstock proportions to be adjusted to achieve desired product distribution,” the researcher explained.
“For example, adjusting the blend ratio and temperature can optimize syngas yield and efficiency.”
This flexibility means the technology could be adapted for different waste streams, allowing operators to optimize fuel production based on available resources.
The researchers also point out that coal-related wastes are an attractive option because they can reduce disposal costs while offsetting environmental impacts from mining residues.
Hydrogen and syngas for a cleaner energy future
Turning plastic waste into hydrogen-rich syngas could transform how society views discarded materials. Instead of being a long-term pollutant, plastics could serve as a valuable source of energy and chemicals.
“Our findings demonstrate the flexibility of cogasification, allowing precise tuning of syngas characteristics for specific downstream applications,” Wang added.
Recovering energy from plastics also prevents the loss of valuable natural resources. Since most plastics are made from oil and gas, recycling them into hydrogen and syngas helps recover their embedded energy content.
This could reduce dependence on fossil fuels while addressing the growing plastic pollution crisis.
The findings were detailed in the journal Fuel.