Fluorinated gases

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Fluorinated gases (F-gases) are a group of gases containing fluorine. They are divided into several types, the main of those are hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulphur hexafluoride (SF6). They are used in refrigeration, air conditioning, heat pumps, fire suppression, electronics, aerospace, magnesium industry, foam and high voltage switchgear. As they are greenhouse gases with a strong global warming potential, their use is regulated. [1]

Contents

Types of F-gases

Atmospheric concentration of SF6, NF3, and several widely used HFCs and PFCs between years 1978 and 2015 (right graph). Note the logarithmic scale. Halogenated gas concentrations 1978-present.png
Atmospheric concentration of SF6, NF3, and several widely used HFCs and PFCs between years 1978 and 2015 (right graph). Note the logarithmic scale.

The most common F-gases are hydrofluorocarbons (HFCs), which contain hydrogen, fluorine, and carbon. They are used in a multitude of applications including commercial refrigeration, industrial refrigeration, air-conditioning systems, heat pump equipment, and as blowing agents for foams, fire extinguishants, aerosol propellants, and solvents. HFC-134a (1,1,1,2-Tetrafluoroethane) has grown to become the most abundant HFC in Earth's atmosphere as of year 2015. [2]

Perfluorocarbons (PFCs) are the compounds consisting of fluorine and carbon. They are widely used in the electronics, cosmetics, and pharmaceutical industries, as well as in refrigeration when combined with other gases. PFCs were commonly used as fire extinguishants in the past and are still found in older fire protection systems. They are also a by-product of the aluminium smelting process. PFC-14 (Carbon tetrafluoride - CF4) has grown to become the most abundant PFC in earth's atmosphere as of year 2015. [2]

Sulphur hexafluoride (SF6) is used primarily as an arc suppression and insulation gas. It can be found in high-voltage switchgear and is used in the production of magnesium.

Nitrogen trifluoride (NF3) is used primarily as an etchant for microelectronics fabrication.

Use history

HFCs were developed in the 1990s to substitute for substances such as chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs). As these substances were found to deplete the ozone layer, the Montreal Protocol began to lay down provisions for them to be phased-out globally after the agreement was ratified in 1987.

PFCs and SF6 were already in use prior to the Montreal Protocol.

NF3 use has grown since the 1990s along with the rapid expansion of the microelectronics fabrication industry.

Environmental impact of F-gases

Annual growths in radiative forcing contributions from atmospheric HFCs and HCFCs have recently peaked near 10%, as compared to steadier 1%-2% growth from the major carbon- and nitrogen-cycle greenhouse gases. Greenhouse gas radiative forcing growth since 1979.svg
Annual growths in radiative forcing contributions from atmospheric HFCs and HCFCs have recently peaked near 10%, as compared to steadier 1%-2% growth from the major carbon- and nitrogen-cycle greenhouse gases.

F-gases are ozone-friendly, enable energy efficiency, and are relatively safe for use by the public due to their low levels of toxicity and flammability. However, most F-gases have a high global warming potential (GWP), and some are nearly inert to removal by chemical processes. If released, HFCs stay in the atmosphere for decades and both PFCs and SF6 can stay in the atmosphere for millennia.

The total atmospheric concentration of F-gases, CFCs, and HCFCs has grown rapidly since the mid-twentieth century; a time which marks the start of their production and use at industrial scale. As a group in year 2019, these unnatural man-made gases are responsible for about one-tenth of the direct radiative forcing from all long-lived anthropogenic greenhouse gases. [3]

F-gases are used in a number of applications intended for climate change mitigation, that can generate further positive feedback for atmospheric heating. For example, refrigeration and air conditioning systems are increasingly utilized by humans within a warming environment. [4] Likewise, expansions of electrical infrastructure, as driven by the alternatives to fossil fuels, has led to rising demand for SF6. [5] If recent trends of aggressive (5% and greater CAGR) annual growth for such types of F-gas production were to continue into the future without complimentary reductions in GWP and/or atmospheric leakage, their warming influence could soon rival those of CO2 and CH4 which are trending at less than about 2% annual growth.

Regulation of F-gases

International level

Although the Montreal Protocol regulates the phasing out of HCFCs, there was no international agreement on the regulation of HFCs until late 2016 when the Kigali Amendment under the Montreal Protocol was signed, which has put compulsory phase wise phasing out of CFC gases. Efforts are ongoing to develop a global approach for the control of HFCs. Most recently, this has taken the form of a declaration of support for a global phase-down as part of the outcomes of the "Rio+20" United Nations Conference on Sustainable Development. [6]

US-level

In the United States, the regulation of F-gases falls under the authority of the Environmental Protection Agency's overall attempts to combat greenhouse gases. [7] The United States has put forward a joint proposal with Mexico and the Federated States of Micronesia for a phase-down of HFCs by 2030. The American Innovation and Manufacturing Act is federal legislation that mandates at 85% reduction in the production and consumption of HFC refrigerants by 2035, in compliance with the Kigali Amendment. [8]

EU-level regulation

In order to combat the potential global warming effects of F-gases, and as part of the EU's Kyoto protocol commitments, in 2006 the European Union passed two pieces of legislation controlling their use: the F-gas Regulation (EC) No 842/2006 and the Mobile Air Conditioning Directive Directive 2006/40/EC. The F-gas Regulation adopts an approach based on containment and recovery of F-gases as well as imposing obligations on reporting, training and labeling on those using F-gases.

On 26 September 2011, the Commission issued a report on the application, effects and adequacy of the Regulation, drawing from the results of an analytical study it commissioned from German environmental research institute, Öko-Recherche. A further study, conducted by the Armines Centre energétique et procédés and by Energy Research Innovation Engineering (ERIE) found that emissions reductions of up to 60% can be achieved by improving containment measures and accelerating the changeover from high GWP refrigerants to ones with lower GWP. [9]

On 7 November 2012, the European Commission published the proposal to revise the F-gas Regulation. In December 2013, the European Parliament and the Council of the EU agreed the text of the revised regulation, which shall be applied from 1 January 2015.

China

There are no regulations regarding SF6 currently in China, even tough some measures for reducing emissions were taken by the government. The emissions of this gas are currently on the rise in China (and in other countries defined as non-Annex-I by the United Nations Framework Convention on Climate Change) "due to their rapid expansion of power demand and fast adoption of renewable energy technologies". In China, they are now close to total greenhouse gas emissions from the Netherlands or Nigeria. [10]

See also

Related Research Articles

<span class="mw-page-title-main">Montreal Protocol</span> 1987 treaty to protect the ozone layer

The Montreal Protocol is an international treaty designed to protect the ozone layer by phasing out the production of numerous substances that are responsible for ozone depletion. It was agreed on 16 September 1987, and entered into force on 1 January 1989. Since then, it has undergone nine revisions, in 1990 (London), 1991 (Nairobi), 1992 (Copenhagen), 1993 (Bangkok), 1995 (Vienna), 1997 (Montreal), 1998 (Australia), 1999 (Beijing) and 2016 (Kigali) As a result of the international agreement, the ozone hole in Antarctica is slowly recovering. Climate projections indicate that the ozone layer will return to 1980 levels between 2040 and 2066. Due to its widespread adoption and implementation, it has been hailed as an example of successful international co-operation. Former UN Secretary-General Kofi Annan stated that "perhaps the single most successful international agreement to date has been the Montreal Protocol". In comparison, effective burden-sharing and solution proposals mitigating regional conflicts of interest have been among the success factors for the ozone depletion challenge, where global regulation based on the Kyoto Protocol has failed to do so. In this case of the ozone depletion challenge, there was global regulation already being installed before a scientific consensus was established. Also, overall public opinion was convinced of possible imminent risks.

<span class="mw-page-title-main">Chlorofluorocarbon</span> Class of organic compounds

Chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) are fully or partly halogenated hydrocarbons that contain carbon (C), hydrogen (H), chlorine (Cl), and fluorine (F), produced as volatile derivatives of methane, ethane, and propane.

<span class="mw-page-title-main">Refrigerant</span> Substance in a refrigeration cycle

A refrigerant is a working fluid used in the refrigeration cycle of air conditioning systems and heat pumps where in most cases they undergo a repeated phase transition from a liquid to a gas and back again. Refrigerants are heavily regulated due to their toxicity, flammability and the contribution of CFC and HCFC refrigerants to ozone depletion and that of HFC refrigerants to climate change.

<span class="mw-page-title-main">Hydrofluorocarbon</span> Synthetic organic compounds

Hydrofluorocarbons (HFCs) are synthetic organic compounds that contain fluorine and hydrogen atoms, and are the most common type of organofluorine compounds. Most are gases at room temperature and pressure. They are frequently used in air conditioning and as refrigerants; R-134a (1,1,1,2-tetrafluoroethane) is one of the most commonly used HFC refrigerants. In order to aid the recovery of the stratospheric ozone layer, HFCs were adopted to replace the more potent chlorofluorocarbons (CFCs), which were phased out from use by the Montreal Protocol, and hydrochlorofluorocarbons (HCFCs) which are presently being phased out. HFCs replaced older chlorofluorocarbons such as R-12 and hydrochlorofluorocarbons such as R-21. HFCs are also used in insulating foams, aerosol propellants, as solvents and for fire protection.

Difluoromethane, also called difluoromethylene, HFC-32Methylene Fluoride or R-32, is an organic compound of the dihalogenoalkane variety. It has the formula of CH2F2. It is a colorless gas in the ambient atmosphere and is slightly soluble in the water, with a high thermal stability. Due to the low melting and boiling point, (-136.0 °C and -51.6 °C respectively) contact with this compound may result in frostbite. In the United States, the Clean Air Act Section 111 on Volatile Organic Compounds (VOC) has listed difluoromethane as an exception (since 1997) from the definition of VOC due to its low production of tropospheric ozone. Difluoromethane is commonly used in endothermic processes such as refrigeration or air conditioning.

1,1,1,2-Tetrafluoroethane (also known as norflurane (INN), R-134a, Klea 134a, Freon 134a, Forane 134a, Genetron 134a, Green Gas, Florasol 134a, Suva 134a, HFA-134a, or HFC-134a) is a hydrofluorocarbon (HFC) and haloalkane refrigerant with thermodynamic properties similar to R-12 (dichlorodifluoromethane) but with insignificant ozone depletion potential and a lower 100-year global warming potential (1,430, compared to R-12's GWP of 10,900). It has the formula CF3CH2F and a boiling point of −26.3 °C (−15.34 °F) at atmospheric pressure. R-134a cylinders are colored light blue. A phaseout and transition to HFO-1234yf and other refrigerants, with GWPs similar to CO2, began in 2012 within the automotive market.

<span class="mw-page-title-main">Chlorodifluoromethane</span> Chemical propellant and refrigerant

Chlorodifluoromethane or difluoromonochloromethane is a hydrochlorofluorocarbon (HCFC). This colorless gas is better known as HCFC-22, or R-22, or CHClF
2. It was commonly used as a propellant and refrigerant. These applications were phased out under the Montreal Protocol in developed countries in 2020 due to the compound's ozone depletion potential (ODP) and high global warming potential (GWP), and in developing countries this process will be completed by 2030. R-22 is a versatile intermediate in industrial organofluorine chemistry, e.g. as a precursor to tetrafluoroethylene.

Fluoroform, or trifluoromethane, is the chemical compound with the formula CHF3. It is a hydrofluorocarbon as well as being apart of the haloforms, a class of compounds with the formula CHX3 with C3v symmetry. Fluoroform is used in diverse applications in organic synthesis. It is not an ozone depleter but is a greenhouse gas.

R-410A, sold under the trademarked names AZ-20, EcoFluor R410, Forane 410A, Genetron R410A, Puron, and Suva 410A, is a zeotropic but near-azeotropic mixture of difluoromethane (CH2F2, called R-32) and pentafluoroethane (CHF2CF3, called R-125) that is used as a refrigerant in air conditioning and heat pump applications. R-410A cylinders were colored rose but are no longer specially color-coded, now bearing a standard light gray color.

<span class="mw-page-title-main">Vapor-compression refrigeration</span> Refrigeration process

Vapour-compression refrigeration or vapor-compression refrigeration system (VCRS), in which the refrigerant undergoes phase changes, is one of the many refrigeration cycles and is the most widely used method for air conditioning of buildings and automobiles. It is also used in domestic and commercial refrigerators, large-scale warehouses for chilled or frozen storage of foods and meats, refrigerated trucks and railroad cars, and a host of other commercial and industrial services. Oil refineries, petrochemical and chemical processing plants, and natural gas processing plants are among the many types of industrial plants that often utilize large vapor-compression refrigeration systems. Cascade refrigeration systems may also be implemented using two compressors.

Organofluorine chemistry describes the chemistry of organofluorine compounds, organic compounds that contain a carbon–fluorine bond. Organofluorine compounds find diverse applications ranging from oil and water repellents to pharmaceuticals, refrigerants, and reagents in catalysis. In addition to these applications, some organofluorine compounds are pollutants because of their contributions to ozone depletion, global warming, bioaccumulation, and toxicity. The area of organofluorine chemistry often requires special techniques associated with the handling of fluorinating agents.

Natural refrigerants are considered substances that serve as refrigerants in refrigeration systems. They are alternatives to synthetic refrigerants such as chlorofluorocarbon (CFC), hydrochlorofluorocarbon (HCFC), and hydrofluorocarbon (HFC) based refrigerants. Unlike other refrigerants, natural refrigerants can be found in nature and are commercially available thanks to physical industrial processes like fractional distillation, chemical reactions such as Haber process and spin-off gases. The most prominent of these include various natural hydrocarbons, carbon dioxide, ammonia, and water. Natural refrigerants are preferred actually in new equipment to their synthetic counterparts for their presumption of higher degrees of sustainability. With the current technologies available, almost 75 percent of the refrigeration and air conditioning sector has the potential to be converted to natural refrigerants.

<span class="mw-page-title-main">1,1-Dichloro-1-fluoroethane</span> Chemical compound

1,1-Dichloro-1-fluoroethane is a haloalkane with the formula C
2H
3Cl
2F. It is one of the three isomers of dichlorofluoroethane. It belongs to the hydrochlorofluorocarbon (HCFC) family of man-made compounds that contribute significantly to both ozone depletion and global warming when released into the environment.

The Intergovernmental Panel on Climate Change (IPCC) with the United Nations Framework Convention on Climate Change (UNFCCC) use tens of acronyms and initialisms in documents relating to climate change policy.

<span class="mw-page-title-main">1-Chloro-1,1-difluoroethane</span> Chemical compound

1-Chloro-1,1-difluoroethane (HCFC-142b) is a haloalkane with the chemical formula CH3CClF2. It belongs to the hydrochlorofluorocarbon (HCFC) family of man-made compounds that contribute significantly to both ozone depletion and global warming when released into the environment. It is primarily used as a refrigerant where it is also known as R-142b and by trade names including Freon-142b.

<span class="mw-page-title-main">Hydrofluoroolefin</span> Class of chemical compounds

Hydrofluoroolefins (HFOs) are unsaturated organic compounds composed of hydrogen, fluorine and carbon. These organofluorine compounds are of interest as refrigerants. Unlike traditional hydrofluorocarbons (HFCs) and chlorofluorocarbons (CFCs), which are saturated, HFOs are olefins, otherwise known as alkenes.

<i>trans</i>-1,3,3,3-Tetrafluoropropene Chemical compound

trans-1,3,3,3-Tetrafluoropropene (HFO-1234ze(E), R-1234ze(E)) is a hydrofluoroolefin. It was developed as a "fourth generation" refrigerant to replace fluids such as R-134a, as a blowing agent for foam and aerosol applications, and in air horns and gas dusters. The use of R-134a is being phased out because of its high global warming potential (GWP). HFO-1234ze(E) itself has zero ozone-depletion potential (ODP=0), a very low global warming potential (GWP < 1 ), even lower than CO2, and it is classified by ANSI/ASHRAE as class A2L refrigerant (lower flammability and lower toxicity).

Life Cycle Climate Performance (LCCP) is an evolving method to evaluate the carbon footprint and global warming impact of heating, ventilation, air conditioning (AC), refrigeration systems, and potentially other applications such as thermal insulating foam. It is calculated as the sum of direct, indirect, and embodied greenhouse gas (GHG) emissions generated over the lifetime of the system “from cradle to grave,” i.e. from manufacture to disposal. Direct emissions include all climate forcing effects from the release of refrigerants into the atmosphere, including annual leakage and losses during service and disposal of the unit. Indirect emissions include the climate forcing effects of GHG emissions from the electricity powering the equipment. The embodied emissions include the climate forcing effects of the manufacturing processes, transport, and installation for the refrigerant, materials, and equipment, and for recycle or other disposal of the product at end of its useful life.

<span class="mw-page-title-main">Kigali Amendment</span> International agreement to reduce the use of hydrofluorocarbons

The Kigali Amendment to the Montreal Protocol is an international agreement to gradually reduce the consumption and production of hydrofluorocarbons (HFCs). It is a legally binding agreement designed to create rights and obligations in international law.

References

  1. ↑ "What are fluorinated gases?". Netregs. The Scottish Environment Protection Agency, Northern Ireland Environment Agency, Northern Ireland's Department of Agriculture, Environment and Rural Affairs. Retrieved 2 April 2024.
  2. 1 2 "Climate change indicators - Atmospheric concentration of greenhouse gases - Figure 4". United States Environmental Protection Agency. 27 June 2016. Retrieved 2020-09-26.
  3. 1 2 Butler J. and Montzka S. (2020). "The NOAA Annual Greenhouse Gas Index (AGGI)". NOAA Global Monitoring Laboratory/Earth System Research Laboratories.
  4. ↑ "Refrigerant Market Size Worth $30.37 Billion By 2025 / CAGR: 5.3%". Grand View Research. 2018-01-31.
  5. ↑ Mark Williams (2020-09-13). "Sulfur Hexafluoride Market is Thriving Worldwide 2020-2027". The Daily Chronicle.
  6. ↑ "The future we want - Outcome document of the United Nations Conference on Sustainable Development" (PDF). United Nations. 2012-06-22. p. 39.
  7. ↑ "Greenhouse gas emissions". Epa.gov. 17 November 2015. Retrieved 2020-09-26.
  8. ↑ "PHASING DOWN HFCS: THE AIM ACT - U.S. Senate Committee on Environment and Public Works". www.epw.senate.gov. Retrieved 2023-05-01.
  9. ↑ "Archived copy" (PDF). Archived from the original (PDF) on 2013-07-20. Retrieved 2013-01-14.{{cite web}}: CS1 maint: archived copy as title (link)
  10. ↑ An, Minde (5 March 2024). "Sustained growth of sulfur hexafluoride emissions in China inferred from atmospheric observations". Nature Communications. 15. Retrieved 2 April 2024.
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