Project EARTH (Environmentally Applied Research Toward Hydrofluorocarbons) is focused on identifying sustainable processes for the selective separation of hydrofluorocarbon (HFC) refrigerant mixtures. Currently, there are millions of kilograms of HFC refrigerant mixtures in use worldwide. These refrigerants have zero ozone depletion potential but many HFCs have high global warming potential (GWP). This has led to recent legislation restricting the use of some HFC refrigerants in particular applications and the eventual phase-out of HFC refrigerants. Consequently, phase-out means that industries across the world will need to dispose of their current HFC refrigerants. Rather than incinerate/vent these high GWP refrigerants to the atmosphere, a process which would both harm the environment and waste millions of kilograms of refrigerants, these refrigerant mixtures could be recycled. To accomplish this, the HFC refrigerant mixtures would first need to be separated into their constituent refrigerants which can be especially difficult because many of the HFC mixtures form azeotropes. Project EARTH members are working to address this difficult separation challenge using the following three separation techniques:
The ionic liquid (IL) portion of Project EARTH is a collaboration project for the measurement and simulation of HFC mixture properties in ILs between the University of Kansas and the University of Notre Dame. The University of Kansas is focused on the material discovery and property measurements of HFCs and ILs and the University of Notre Dame is focused on Monte Carlo simulations and process modeling/optimization of ILs and HFC/IL mixtures. ILs are of particular interest in this project because of their unique properties including no measurable vapor pressure, dissolution of many organic and inorganic compounds, variable solubility of gases and liquids, and high thermal, chemical, and electrochemical stability. These properties have allowed ILs to be used in many different applications including separation and purification processes. Our goal is to determine the most efficient ILs for the HFC separations.
Membranes provide a unique opportunity for the separation of HFC refrigerant components, as membrane technology has the potential of having smaller energy and capital requirements than traditional separation techniques. Membranes can be described as a barrier that selectively allows the passage of some species while preventing the passage of others. While semipermeable polymers are the most common membranes, different components and compositions can be incorporated to influence membrane selectivity and permeability, thus making it possible to design membranes capable of difficult HFC separations. While much research has been devoted to the separation of refrigerants from air streams, there has been little exploration of membrane technology for the separation of refrigerant mixtures. In the membrane division of Project EARTH, various types of membranes and membrane compositions will be explored for separating HFCs.
The term porous media applies to various different nano to micro-sized materials such as zeolites, activated carbons (ACs), and metal organic frameworks (MOFs). Dr. David R. Corbin (DuPont Senior Research Fellow, retired) with over forty years of zeolite experience is working in our group as a Senior Scientist assisting with Project EARTH. Zeolites are hydrous, aluminosilicate, porous crystals which are used extensively in industry for both catalysis and molecular separations. Due to their interconnected, uniform pores, zeolites can be exploited for both their molecular sieve capabilities and chemical properties. Zeolites are therefore a good candidate for performing the challenging separations which are required for HFC refrigerant mixtures.
Project EARTH Partners:
Rutgers University, University of Notre Dame, Texas A&M University, The Chemours Company, The Wonderful Company, Hiden Isochema, Iolitec