Ann Lee-Jeffs, Green Chemistry Program Manager at ACS Green Chemistry Institute (ACS GCI) had an engaging interview with Rajiv Banavali,Chief Technology Officer, Fluorine Products at Honeywell about some of the exemplary new climate change-abating chemistries of the 21st century such as Honeywell’s Solstice® platform of refrigerants, foam blowing agents, solvents and propellants.
Lee-Jeffs: Tell me about your new Solstice® platform and how your team designed these exciting new products.
Banavali: I appreciate the opportunity to share our proud story about our new Solstice® products, which were designed to replace existing refrigerant, foam blowing agent, solvent and aerosol technology. First, let me explain why these products were needed.
Climate change is one of the biggest 21st century global challenges. In the 5th Assessment Report from the Intergovernmental Panel on Climate Change (IPCC), published in April 2014, the Report warns that unless serious action is taken, the effects of climate change are likely to get worse with growing risks of floods, food shortages, and threats to human health. As the concern over climate change continues to grow globally, a great deal of focus has been placed on the use and emission of hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs). These “greenhouse gases” have global warming potentials (GWPs) that are sometimes thousands of times higher than CO2. GWP is a measure of the amount of global warming impact per unit weight of the material, relative to the same weight of carbon dioxide (CO2). Thus, HFCs and HCFCs could account for significant total global warming impact. And it is estimated that this contribution c ould further increase if left unchecked.
Concerns over the contributions of HCFCs and HFCs to climate change have prompted many countries to adopt aggressive phasedown or phaseout strategies.
Europe has enacted “F-gas” regulations that are phasing out HFC-134a in automobile air conditioning, and the EU is in the process of finalizing additional restrictions on the use of HFCs. The U.S. has largely phased out HCFCs, and it hopes to add HFCs to the Montreal Protocol with the goal of a significant phasedown of HFCs over the next 20 years. The phase-out of ozone depleting substances under the Montreal Protocol resulted in greenhouse gas emissions reductions of 11 GtCO2-eq/year, or 5 to 6 times the reductions mandated for all greenhouse gases in the reporting period of the Kyoto Protocol (2008-2012). This was facilitated largely by substituting HFCs for CFCs. HFCs are known contributors to climate change and phasing down their use is a key to mitigating atmospheric CO2 equivalents which are the major contributors to climate change.
Honeywell saw clearly that low-GWP alternatives to HCFC and HFCs were needed to help solve this worldwide problem. As a leader in fluorine chemistry for more than 70 years we saw the need to develop replacement options that meet the world’s future needs for refrigerants, foam blowing agents, solvents and aerosols. Based on their prior work and proprietary knowledge, researchers at Honeywell created an initial list of more than 1,000 molecules that Honeywell believed could be considered as low-GWP alternatives to existing HFCs. These researchers began the task of narrowing this lengthy list by assessing various criteria including desirable and required properties such as persistence in the environment, toxicity, flammability, miscibility, stability and others. In an effort to streamline the list of candidate molecules further, Honeywell researchers also performed intensive testing on what they considered to be promising candidates. Eventually, and contrary to the thinking in the industry at the time, Honeywell researchers decided to focus their further research efforts on fluorinated olefins, particularly partially fluorinated three-carbon molecules – fluorinated propenes. Prior to Honeywell’s work, none of the fluorinated olefins had been considered worthy of investigation by the industry due to their perceived unacceptably high reactivity, instability and/or toxicity. Nevertheless, Honeywell researchers found that this class of molecules offered a potential low GWP solution as well as one that might fit into Honeywell’s existing technology base. Indeed, Honeywell was the first to develop a commercial solution involving use of any of the fluorinated olefins, for any application.
After all of this work we demonstrated that hydrofluoro-olefins are excellent candidates to replace existing HFCs, while at the same time providing safety benefits over the flammable hydrocarbon blowing agents currently in use, such as cyclopentane. In the IPCC’s AR5 report the 100-year GWP values for Honeywell’s pure HFO products are less than or equal to 1, making them equal to or less than CO2, which is the baseline, and 99.9% lower than the products they replace. These new products are marketed under the trade name Solstice®
These products have short atmospheric lifetimes because of the double-bonded structure that allows them to break down more rapidly in the atmosphere – 26 days as opposed to many years.
Lee-Jeffs: Let’s focus on HFO-1233zd(E), for a moment, which appears to be quite versatile since it can be used as a solvent, a refrigerant and a foam blowing agent.
Banavali: Yes, let me tell you about HFO-1233zd(E), also called Solstice® Liquid Blowing Agent (LBA), Solstice® Performance Fluid (PF), and Solstice® zd refrigerant. It was designed and engineered in Honeywell’s Buffalo, New York, research laboratories. HFO-1233zd(E) technology is supported by more than 600 issued or pending worldwide patents on unique compositions, uses and methods of manufacture. The molecule has been granted VOC-exempt status by the U.S. EPA and is listed under the EPA's Significant New Alternatives Policy (SNAP) and is on the TSCA inventory. In 2013, Honeywell announced that it would invest more than $200 million at its four production facilities in Louisiana and create 500 new direct and indirect jobs. These investments included a new plant to make HFO-1233zd(E), which began production in May 2014, and Honeywell is currently working on a second, world-scale, U.S. plant.
Lee-Jeffs: Can you describe how HFO technology contributes to improving foam blowing agents?
Banavali: Rigid polyurethane foam (PU Foam) insulation, also known as closed-cell spray polyurethane foam (ccSPF), has been the construction industry’s gold standard for high performance thermal insulation for the past 60 years. The main reason for this outstanding performance is the gas that is trapped in the foam’s closed cell structure which accounts for as much as 75% of the foam’s thermal insulation value [Klempner et al; Handbook of Polymeric Foams and Foam Technology, 2004 p. 44]. The same gas is used to expand the foam and is called the blowing agent. Because the blowing agent serves the dual purpose of expanding and providing the insulation value to the foam the choice of blowing agent is critical. In addition to having a combination of desirable properties, including acceptable physical, safety, and other parameters, selection of a blowing agent with low vapor phase thermal conductivity and permanence in the foam’s cells is critical to produce the highest performance foam.
One of the most common applications for PU foam is the insulation of refrigerators and freezers (appliances). In addition, because of its considerable structural strength, PU foams also serve as the main structural component of refrigerator cabinets and doors. The use of PU foam and fluorocarbon blowing agents has been one of the main reasons for the energy efficiency improvements seen in refrigerators over the last 30 years. For example, refrigerators made today typically use about half the energy as new refrigerators did in 1990.
Solstice® LBA is also used in many other foam insulation applications including insulated building panels, spray foam for walls and roofs, panels for refrigerated trucks, and refrigerated shipping containers.
Lee-Jeffs: What is different about HFO-1233zd(E)? What makes it special?
Banavali: The biggest challenge we encountered when starting our search for low-GWP alternatives was that the products would have to be stable enough not to react or break down in their intended application and at the same time be unstable enough to decompose in the atmosphere quickly, all without the creation of hazardous breakdown products. Honeywell’s researchers had solved difficult technical problems before, and we were ready for the challenge. At our request, detailed investigation was conducted by researchers around the world to determine the potential atmospheric oxidation breakdown products of HFO-1233zd(E), including the products of both chlorine atom and hydroxyl (OH) radical-initiated oxidation, as represented by the following equations:
The presence of the double bond results in rapid reaction with these radicals which is unlike any existing fluorinated product. The major products are HCl, CF3CHO and HCOCl. In the atmosphere HCOCl is anticipated to be incorporated into rain or other forms of moisture and to hydrolyze to form formic acid, a ubiquitous component of the environment. The aldehyde, CF3CHO, will undergo photolysis in the atmosphere resulting in an estimated lifetime of 2 and HF through oxidation and hydrolysis. Because these final breakdown products already occur in nature and at the anticipated levels in the environment the atmospheric oxidation products are not of concern.
Lee-Jeffs: Tell me about the safety and toxicological profile of HFO chemistry.
Banavali: We partnered with leading independent research institutes to conduct extensive tests (more than 10 toxicology studies) over a period of many years to assess HFO-1233zd(E) for potential impact on humans and the environment, and we found it to be safe for its intended uses.
This testing has been vetted and verified by the Occupational Alliance for Risk Science (OARS) Workplace Environmental Exposure Limits [WEEL] Committee, a group of well-recognized experts, which has issued a Permissible Exposure Limit (PEL) of 800 ppm versus 300 ppm for HFC-245fa. Additionally, Solstice® LBA has been approved by U.S. EPA (under the SNAP and PMN programs). It has been E.U. REACH registered for more than 1,000MT (the highest level), and has been registered in Japan, Australia, and a host of other countries.
Lee-Jeffs: Where are you with commercialization of HFO-1233zd(E), and what are your aspirations for the product?
Banavali: As mentioned previously, Honeywell started up a world-scale manufacturing plant in Louisiana in May 2014. Honeywell and its suppliers plan to invest $900 million in the Solstice® platform in the coming years. Honeywell projects that use of its low-GWP Solstice® products designed to replace HFCs will eliminate more than 350 million metric tons in CO2 equivalents by 2025, which is equal to removing 70 million cars from the road for one year.
HFO-1233zd(E) is being adopted globally as a foam blowing agent in appliance insulation, spray foam insulation, as a high-performance solvent and as a refrigerant. Let me share some examples.
Whirlpool started manufacturing refrigerators with Solstice® LBA in late 2013 at its Amana, Iowa, factory and has transitioned its entire U.S. product line to Solstice® LBA. Several Chinese appliance manufacturers, including Haier, Midea and Hisense, are also transitioning to Solstice® LBA to meet increasing standards in China, the U.S. and Europe. Numerous other global OEMs in the U.S., Europe, Japan, China, Korea, and India are in various stages of development and are expected to transition to Solstice® LBA in the near future.
Solstice® LBA is also making significant inroads across the globe through the construction industry. Spray foam made with Solstice® LBA is a highly energy efficient solution for construction because of its higher thermal insulation value compared to other solutions and also because it provides a thermal, moisture and air barrier which eliminates the need for other materials. Lapolla, a large foam systems house based in Houston, Texas, adopted Solstice® LBA for wall spray foam in 2014, and it has been used in several high profile projects with great results.
Closed-cell foam made with Solstice® LBA can also be used as high density spray foam roofing. When compared to current HFC-245fa based systems it offers 2-4% higher insulation value(giving about 10% better yields (materials savings)), makes a stronger end product (foam), and has a greater resistance to hail. West Development Group has completed dozens of spray foam roofing projects all over the U.S., including a great example at the Cleveland Airport System where they put down over half a million square feet of roofing over two airports.
Solstice® LBA is also being used in insulated panel or board applications in Europe. Kingspan, the largest construction board manufacturer in the world, announced recently that it is able to offer more energy efficient and lower climate impact boards using Solstice® LBA.
The solvents, metal precision, and electronics cleaning industries had long depended on ozone-depleting solvents like 141b and 225. The phase-out of these solvents has caused the industry to choose alternatives with less favorable flammability or toxicity profiles. It has been shown that Solstice® Performance Fluid (PF) is an excellent solvent in those applications. It improves performance by decreasing energy usage and cleaning cycle time.
Shifting gears to refrigerants, centrifugal chillers are capable of achieving the HVAC industry’s highest levels of efficiency. Ninety-five percent of a typical chiller’s GWP is attributable to the CO2 emissions from generating electrical power. Solstice® zd refrigerant has comparable efficiency to R-123 – the current refrigerant used with a GWP of 79. Trane, a leading global provider of centrifugal chillers announced its adoption of Solstice® zd refrigerant in its Series E CenTraVac chillers
Lee-Jeffs: Do you have any concluding remarks?
Banavali: HFO-1233zd(E) is a great example of a made-in-America chemical innovation that will help the world dramatically reduce its climate impact, improve energy efficiency, improve costs, and create jobs - all in a safe way. HFO-1233zd(E) is being adopted globally in a wide variety of industries such as appliances, transport, construction, refrigerants, and precision cleaning for electronics. Leading-edge companies such as Whirlpool, Midea and Trane are transitioning to Honeywell’s unique low-GWP HFO-1233zd(E). Wide-spread use of HFO-1233zd(E)to replace HFCs in these industries in the U.S. alone will result in a reduction of more than 25M tonnes per year of CO2-equivalent; globally this number would exceed 90M tonnes (based on Honeywell’s internal analysis). This new product will not only help reduce global warming, but it will spur economic growth and job creation in the U.S.
We continue to be excited about the positive impact our Solstice® products can have, not only on the environment but also on the world.
Rajiv Banavali, Chief Technology Officer, Fluorine Products, Honeywell.
Rajiv currently leads the global technology organization for Fluorine Products within the Performance Materials and Technology (PMT) division of Honeywell. Prior to his current Fluorine Products technology executive leadership role, Rajiv led the Specialty Chemical division business unit of Honeywell. Before his tenure at Honeywell, Rajiv spent 22 years with Rohm & Haas as R&D Director.
Ann Lee-Jeffs, Green Chemistry Program Manager, ACS Green Chemistry Institute
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