PFI-TT: Separation of azeotropic refrigerant mixtures using pilot-scale extractive distillation with ionic liquid entrainer

University Of Kansas Center For Research Inc, Lawrence KS

Investigators

Abstract

The broader impact/commercial potential of this Partnerships for Innovation – Technology Translation (PFI-TT) project seeks to provide certified refrigerant reclaimers with a new technology for separating azeotropic refrigerant mixtures. The Heating, Ventilation, Air-Conditioning, and Refrigeration (HVAC) industry tries to recover as much refrigerant as economically practical for reuse, but reclaimers are now challenged by an array of complex, multi-component mixtures that, in many cases, are not possible to separate and ultimately must be stockpiled or destroyed. The American Innovation and Manufacturing Act of 2021 requires the phase down in production and consumption of hydrofluorocarbon refrigerants in the U.S. by 85 percent over the next 15 years with a focus on reducing high global warming potential gases. Currently, there are several billion kilograms of refrigerants in existing cooling systems that must be separated and recycled. Voice-of-customer data gathered in over 100 interviews indicates that a new technology for separation of azeotropic refrigerant mixtures is now needed and only about 5% of refrigerant is recovered. Outreach activities, especially toward the inclusion of underrepresented minorities and women will be supported through this project. Students will develop entrepreneurial and technology commercialization skills and work with a start-up company to take the innovation to the marketplace. The proposed project seeks to demonstrate the first pilot-scale process using extractive distillation and an ionic liquid entrainer for separating refrigerant R-410A. The refrigerant is composed of 50 wt% difluoromethane and 50 wt% pentafluoroethanee. The incumbent technology, fractional distillation, cannot separate this azeotropic mixture into pure components. Ionic liquids are salts that are liquid at room temperature, which can be designed to achieve high separation selectivity for refrigerant gases. R-410A is the largest volume refrigerant mixture sold in the U.S. Currently, there is approximately 100 million kilograms of R-410A used in residential and commercial air-conditioners and heat pumps. The difluoromethane has a relatively low global warming potential and can be repurposed into future refrigerant products. The pentafluoroethane has a high global warming potential and can be used as a fluorinated feedstock for producing new environmentally-friendly products. The key research objectives include: separation of R-410A into products with a purity of 99.5 wt% or higher, creation of a process simulation model that represents the experimental results, and testing the actual reclaimed R-410A from the industry to understand the effects of impurities. The results will be used to develop a financial model for estimating the costs for separating azeotropic refrigerants. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.