EFRI DChem: Next-generation Low Global Warming Refrigerants

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This EFRI DCHEM Distributed Chemical Manufacturing Project, named EARTH (Environmentally Applied Research Towards Hydrofluorocarbons), will use high-fidelity experiments, advanced computer simulations, and rigorous analytical methods in a coordinated framework to discover, synthesize, and test a new type of fluid called an ionic liquid that can be used to separate, recycle, and convert high global warming potential (GWP) refrigerant mixtures into safe products. The research will be conducted by a team of researchers located at the University of Kansas, the University of Notre Dame, Texas A&M University, and Rutgers University in collaboration Brookhaven National Lab, Oak Ridge National Lab and the National Institute of Standards and Technology and two industry partners (Chemours and Iolitec). The technical, economic, and environmental impacts of the project are considerable, given the large inventory of high GWP refrigerants that must be removed from the market. The market for recycling refrigerants is valued at more than a billion dollars and preventing the release of high-GWP refrigerants into the Earth’s atmosphere is equivalent to eliminating 175 million metric tons of CO2 (or annual emissions from 50 million cars). The project has the potential to economically benefit the refrigerants business and provide a distributed chemical manufacturing process for over 100 EPA certified recyclers in the U.S. A multi-faceted strategy will be employed to maximize dissemination and knowledge sharing with the broader scientific community. The four lead institutions are committed to providing a safe and inclusive environment and will recruit five PhD students, one post-doctoral researcher, and eight undergraduates. These researchers will be provided with cross-disciplinary training in science and engineering, attend STEM workshops and safety meetings, and intern in partnering universities, companies, and national labs.This project will provide the fundamental knowledge and innovation required to recycle and repurpose high-GWP refrigerants. The project is built upon the tunable solvation properties of ionic liquids (ILs) to realize the separation of azeotropic HFC mixtures that are not possible with other materials. The two primary goals are (1) designing chemical separations with high selectivity and capacity for complex systems and (2) understanding temporal changes that occur in chemical separation systems. Six fundamental aims will integrate property measurements and equation of state modeling (Aim 1), molecular simulations and design (Aim 2), advanced materials development (Aim 3), spectroscopy, scattering, and molecular interactions (Aim 4), process modeling and optimization (Aim 5), and design and implementation of lab-scale separation systems (Aim 6). Using proven experimental methods, the team will measure the thermophysical properties and vapor-liquid-equilibria required for designing an extractive distillation, absorption, or membrane process. High-throughput molecular dynamics and Monte Carlo simulations will be used to calculate the solubility (phase equilibrium), selectivity, and transport properties of a large number of refrigerant-IL systems using molecular force fields validated by experiment. New ILs with fluorinated ions will be synthesized to explore the “chemical” space connecting refrigerants and ILs. The team will utilize a number of techniques to determine refrigerant-IL interactions including: pulse-gradient-spin-echo (PG-SE) NMR experiments for measuring self-diffusion, nuclear Overhauser effect (NOE) experiments for studying intermolecular interactions, synchrotron X-ray scattering experiments for providing liquid structure factor S(Q), inverse Fourier sine transform for radial pair distribution function g(r), and quasi-elastic neutron scattering (QENS) for dynamical specific length scales as examples. The efficacy of the novel ILs designed in this work will be demonstrated via design optimization and a set of simulations and experiments for extractive distillation, absorption, and membrane separation processes.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.