Drexel Joins EPA Effort to Prevent Greenhouse Gas Emissions from Refrigerant Chemicals

Drexel researchers will join an EPA effort to develop technology that can destroy greenhouse chemicals, called hydrofluorocarbons, used in cooling units.

Researchers from Drexel University have been tapped to join an Environmental Protection Agency initiative to eliminate greenhouse gas chemicals called hydrofluorocarbons (HFCs), commonly used in refrigerants and insulating foams. As part of a federal initiative to address the potent, climate-damaging gasses, Drexel will receive $3.8 million over five years to develop a plasma arc device that can destroy HFCs.

While HFCs represent just 2% of all greenhouse gas emissions, each kilogram of HFCs causes 3,000 times more global warming than a kilogram of carbon dioxide— which accounts for 76% of greenhouse gas emissions. The 2020 American Innovation and Manufacturing Act placed the chemicals squarely in the EPA’s crosshairs, designating them for 85% reduction by 2036 through mandated phasedowns, transitioning to new technology, and supporting research to minimize release, reclaim and destroy HFCs.

Drexel’s is one of five projects, recently tabbed for funding in a $15 million EPA effort to reclaim and destroy the chemicals.

“HFCs are extremely potent global warming chemicals,” said Christopher Sales, PhD, an associate professor in Drexel’s College of Engineering who is a leader of the project. “Creating a technological approach to effectively destroy HFCs is critical in reducing their emissions into the environment.”

The current process for handling spent refrigerant chemicals involves a licensed technician carefully collecting them and taking them to a reclamation facility where, if they are not contaminated with other chemicals, they can be recycled for reuse or, if they are contaminated, they must be safely destroyed using an EPA-approved technology.

The goal of the EPA’s new program is to take HFCs out of circulation by replacing them with environmentally friendly alternatives in newer cooling technologies. A global phasedown of HFCs is expected to avoid up to 0.5°C of global warming by 2100, according to the Agency.

The challenge of the task lies in destroying HFCs without allowing them to escape into the atmosphere in the process. HFCs enable refrigeration by circulating as a liquid, absorbing heat and evaporating — producing a vapor that is pumped into the refrigerator’s cooling coils. Because of this low evaporation point, destroying HFCs while they are still in a liquid form is rather challenging.

This is why Drexel’s approach, which uses non-thermal — or so-called “cold” — plasma could be effective. Cold plasma directs a beam of highly reactive species (plasma), such as electrons, ions and radicals, that can break down complex molecules, like HFC, without the need for high-temperature incineration. The technology is currently being used to sterilize medical equipment and decontaminate produce, but the team believes it could easily be adapted to target HFC-contaminated oil that is drained from the compressor of a cooling system.

“Non-thermal plasma’s selective nature means that it can be used to destroy hydrofluorocarbons while reducing the formation of unwanted byproducts,” said Jinjie He, PhD, an assistant research professor in Drexel’s C. & J. Nyheim Plasma Institute, who is part of the team leading the project. “This will ensure a cleaner and more controlled process. Additionally, its versatility and scalability make NTP an ideal technology for both lab-scale and industrial-scale applications, contributing to sustainable and efficient HFC reclamation and destruction.”

Drexel has been a pioneer in developing non-thermal plasma for environmental applications for decades. At the University’s Nyheim Plasma Institute, researchers have created and tested the technology for water treatment, and removal of chemical contamination and fouling agents from filtration systems. Most recently, Sales and his collaborators at the Institute have been testing cold plasma for removing PFAS, also known as “forever chemicals” from water.

The team plans to create a portable gliding arc integrated liquid incineration system — a device that uses plasma to carefully incinerate the HFC-laden oil from the refrigerant reclamation process.

While non-thermal plasma technology is inherently less energy intensive than thermal plasma, an additional benefit of Drexel’s approach is that the plasmatron would be able to use the excess oil as fuel. Approximately 97% of the lubricant oil drained from cooling systems does not contain HFCs, so it could safely be used to power the system — making the process more energy efficient.

“The use of an integrated liquid incineration system is the most logical form of incineration to be used for this HFC-laden oil, particularly because it typically requires additional fuel to elevate the temperature within the reactor,” said Alexander Fridman, PhD, John A. Nyheim chair professor in the College of Engineering and director of the Nyheim Plasma Institute, who is also leading the project. “Given that this waste stream contains 97% oil, it would serve as an ideal supplementary fuel for the reactor.”

Over the next five years, the team, which includes researchers from across the University, will build and test a prototype of the portable plasmatron device. They will also measure the environmental impact of the process, including its energy cost and emissions.

“One of the critical aspects of this effort is assessing the degradation of HFCs to ensure that no harmful byproducts are being released into the atmosphere in the process of destroying them,” said Ezra Wood, PhD, an associate professor in Drexel’s College of Arts and Sciences, who will lead this monitoring. “We will be carefully testing our process to ensure compliance with air emissions standards for byproducts.”

The team will also work with community outreach experts from Drexel’s Environmental Collaboratory, to educate communities near refrigeration facilities and potential sites for reclamation and destruction of HFCs, so they are aware of how the problem is being addressed and of the safety measures being taken to protect communities from the environmental effects of these greenhouse gasses.

“From an environmental justice standpoint, many of the facilities that still contain HFC refrigerants are located near communities that have historically been disenfranchised from advocating for environmental safety measures,” said Mira Olson, PhD, an associate professor in the College of Engineering who will be leading community outreach as part of the Environmental Collaboratory. “In order for the EPA’s effort to be successful, educational outreach and advocacy alongside these communities are critical steps in the process.”

In addition to Sales, Fridman, He, Wood and Olson, Alexander Rabinovich, PhD, a research professor and associate director of the Nyheim Plasma Institute, will be participating in this project.

For more information on the American Innovation Manufacturing Act and its implementing regulations, visit https://www.epa.gov/climate-hfcs-reduction.