Post on 07-Aug-2020
Two Home Runs for Honeywell: Chemistry to Save the Ozone Layer without Global Warming
Ian Shankland
2Nov 6, 2019
My Talk Today
1. Why & where CFCs were used
2. Ozone depletion and CFC replacements
3. Global warming - replacing the CFC replacements
Chemistry That Saves The Ozone LayerAnd Reduces Global Warming Impact
3Nov 6, 2019
Top 20 Engineering Achievements*
*National Academy of Engineering
4Nov 6, 2019
The Ice Man Cometh
• 1800s: winter ice harvesting
• Ice deliveries for the home icebox
• Ice used in food transportation
• Late 1800s to early 1900s: mechanical refrigeration for breweries and ice making
• Primary refrigerant was ammonia
5Nov 6, 2019
Mechanical Refrigeration For The Home
Pre-1930 Refrigerants• Methyl chloride: toxic & flammable• Ethyl chloride: toxic & flammable• Sulfur dioxide: toxic• Butane: flammable• Ammonia: toxic & flammable
• Significant safety issues limited the wide adoption of refrigeration and air conditioning
• Many issues, including fatalities from leaking refrigerants like CH3Cl and SO2
6Nov 6, 2019
1929 Cleveland Hospital Fire
• Methyl chloride gas escaped, causing a disastrous explosion in a Cleveland hospital
• More than 120 deaths• Fatalities attributed to fire and inhalation
of CH3Cl and other noxious gases from celluloid x-ray film combustion
• This, and other incidents, lead to pressure to ban refrigerants
Strong Need For Safe Refrigerants
7Nov 6, 2019
CFCs (ChloroFluoroCarbons) Invented
• 1931: CFC-12 commercialized for refrigeration• Nonflammable• Low toxicity• Excellent thermodynamic properties• Excellent energy efficiency• Chemically stable
Thomas Midgely
Fluorocarbon Numbers4-digit code: CFC-12 0012
Add 90 01020102 = 0 double bonds, 1 C, 0 H & 2 FAll other available valence positions filled with Cl0102 = CF2Cl2
8Nov 6, 2019
Glossary
• CFC: Chlorofluorocarbon• HCFC: Hydrochlorofluorocarbon• HFC: Hydrofluorocarbon
• ODP: Ozone Depletion Potential – Potential of a substance to deplete stratospheric ozone relative to that
of the same mass of CFC-11 (ODP = 1)
• GWP: Global Warming Potential– Ratio of atmospheric warming (radiative forcing) caused by a substance
relative to the same mass of CO2 (GWP = 1) over a 100 year time horizon.
9Nov 6, 2019
CFC-12: Refrigeration, car air conditioning, aerosols, freezing food, medical equipment sterilization, polystyrene foam, chillers
CFC-11: Polyurethane foam insulation, large water chillers
CFC-113: Solvents for cleaning electronics, metals, medical devices, aerospace parts
HCFC-22: Home & building air conditioning, supermarket refrigeration
1931 – 1970s: Other CFCs & Uses Developed
10Nov 6, 2019
Stratospheric Ozone Layer• Ozone (O3) layer protects the
earth from ultraviolet radiation• Ozone levels vary naturally – day/night,
summer/winter & solar cycles• Stratospheric ozone at 1 atmosphere
pressure and 0°C would be 3 mm thick(300 Dobson units)
• 1960s: Research on atmospheric impact of supersonic aircraft • 1973: J. Lovelock detects CFCs in the atmosphere• 1974: S. Rowland & M. Molina warn of ozone depletion from CFCs• 1978: U.S. bans CFCs in most aerosols• 1985: Antarctic ozone hole discovered• 1987: Montreal Protocol on Substances that Deplete the Ozone Layer• 1995: Crutzen, Molina & Rowland awarded Nobel Prize for Chemistry
11Nov 6, 2019
Ozone Destruction
• CFC-12 (CF2Cl2) Chemically stableAtmospheric lifetime ~ 120 years
• CFC-12 reaches the stratosphere
• Ultraviolet radiation breaks the C-Cl bond
• Cl atoms catalytically destroy ozone
12Nov 6, 2019
CFC Replacements
• CFCs phased out in the 1990s (later in developing countries)
• Many industries impacted:– Air conditioning, refrigeration, electronics, medical, aerospace,
building construction, personal care products, pharmaceutical, fire extinguishing and more
• Conservation & switching to other materials, e.g. hydrocarbons decreased CFC usage
• However, the need for environmentally safer materials with attributes similar to the CFCs still existed
13Nov 6, 2019
Exemplary CFC Replacement Attributes
• Use in existing equipment• Energy efficient
Functional in the Application
• Low toxicity• Acceptable flammability
Safe in Use
• Very low or zero ODPReduced global warming impact
EnvironmentallyAcceptable
• Economically Viable
• Commercially AvailableViable
Technology
14Nov 6, 2019
CFC Substitute Environmental Criteria
• Minimal to zero ODP– Preferably no Cl or Br
• Atmospheric breakdown products thatdo not create environmental issues
• Initial choices were HCFC or preferably HFC materials– HFCs have zero ODP and reduced
GWP values compared to CFCs– HCFCs offered significant
reductions in ODP
Partially halogenated alkanes react with trace components present in the troposphere
RF-H + ·OH à RF· + H2ORF· à à à
RF-H = HFC or HCFC
ODPHFC-134a 0
HCFC-22 0.05HCFC-141b 0.11
CFC-12 1.0
EnvironmentallyAcceptable
15Nov 6, 2019
CFC Substitute Toxicological Testing
• Acute Toxicity
• Environmental Toxicity
• Genotoxicity (Mutagenicity)
• 4-Week Inhalation Test
• Sub-chronic (13-Week) Inhalation Test
• Developmental Toxicity (Teratology)
• Reproductive Toxicity
Testing Programs Require 2-6 Years To Complete… Required By Regulatory Agencies
Safe In Use
16Nov 6, 2019
Vapor Compression Refrigeration
• Thermodynamic properties• Transport properties• Refrigeration capacity• Energy efficiency• Dielectric properties
• Lubricant miscibility• Chemical stability with lubricant, metals,
polymers, trace amounts of water• Thermal stability• Acceptable flammability properties
Exemplary Complex & Multi-Dimensional Performance Requirements
Functional In The Application
17Nov 6, 2019
Non-Ozone Depleting Materials
• New molecules developed:– No chlorine = no ozone depletion– (No bromine = no ozone depletion)– Shorter atmospheric lifetimes
• Thorough testing by manufacturers – Safety (low toxicity & nonflammable)– Environmental properties– Safe & efficient manufacture– Performance testing
• Thorough testing by end users– Safety– Performance– Reliability
EXAMPLE• HFCs: Hydrofluorocarbons• HFC-134a: CF3CFH2
– ODP=0– GWP =1,430 vs 10,900 for CFC-12
• Replaces CFC-12– Very safe– Good energy efficiency– But not a “drop-in”– More complex manufacturing
18Nov 6, 2019
Non-Ozone Depleting Substances 1990-2005
• HFC-134aCF3CFH2
• HFC-125 CF3CF2H
• HFC-32 CF2H2
• HFC-143a CF3CH3
• HFC-245faCF3CH2CF2H
• HFC-365mfcCF3CH2CF2CH3
Automobile Air Conditioning Appliances
Pharmaceutical Applications
Home Air Conditioning
Supermarket RefrigerationCommercial Air
Conditioning
Aerosols Foam Insulation Appliances
19Nov 6, 2019
Stra
tosp
heric
Cl +
Br
1980 2100
2006 “The combined stratospheric abundances of the ozone-depleting gases show a downward trend from their peak values of the late 1990s, which is consistent with surface observations of these gases and a time lag for transport to the stratosphere.”Scientific Assessment Of Ozone Depletion: 2006
Developed Economy Countries:
• CFCs phased out
• HCFCs phased out
Developing Economy Countries:
• CFC phase-out complete 2010; some concern about compliance
• HCFC freeze at ’09/’10 levels in 2013and 97.5% reduction by 2030
The Montreal Protocol Is Working
Scientific Assessment Of Ozone Depletion: 2006
20Nov 6, 2019
The Polar Ozone Holes
Phys.org Feb 10, 2013 — Satellites show that the recent ozone hole over Antarctica was the smallest seen in the past decade. Long-term observations also reveal that Earth's ozone has been strengthening following international agreements to protect this vital layer of the atmosphere.
21Nov 6, 2019
2019 Antarctic Ozone Hole
• “Ozone hole season”: Sep-Nov• Ozone hole is unprecedentedly
small area for this time of year
22Nov 6, 2019
The Greenhouse Effect
Solar RadiationAbsorbed By The Earth’s SurfaceSome Radiation Is Reflected
1
22
1
Greenhouse Gases (GHGs)• CO2
• Methane & Nitrous Oxide• Halocarbons – Including HFCs
Greenhouse Effect è Global Warming è Climate Change
Earth’s Surface Warms & Re-emitsGreenhouse Gases Trap Radiation
Radiative Forcing = (EnergyIn – EnergyOut)/m2s
23Nov 6, 2019
Global Warming Potential Values
GWP100
HFC-152a CH3CHF2 140
HFC-32 CH2F2 650
HFC-245fa CF3CH2CHF2 950
HFC-365mfc CF3CH2CF2CH3 900
HFC-134a CF3CH2F 1,440
HFC-125 CF3CHF2 2,800
HFC-143a CF3CH3 3,800
Major HFC Products
24Nov 6, 2019
Climate Change Regulations
Growing GHG Emissions• Main Culprit Is CO2
• HFCs Are “Visible” Due To High GWP
EU F-Gas Directive• Mobile Air Conditioning Directive
– 2011: GWP<150 New Platforms– 2017: GWP<150 All New Vehicles
• GWP < 150 for certain aerosol applications July 2008 & July 2009
Kyoto Protocol• 5.2% Average GHG Reduction• Creates Emissions Trading Markets`
1
2
3
4
5
6
01990 2010 2030 2050
CarbonDioxide
CFCs HCFCsMethane
Nitrous Oxide
HFCs
Rad
iativ
e Fo
rcin
g, W
m-2
Business As Usual ModelBusiness As Usual Scenario UNEP / EPA Scenario for HFCsIPCC (IS92a) Scenario for other gases
25Nov 6, 2019
Representative Property Data For Select Low GWP Materials
Structure Atmos Life GWP VOC
Status*
1234yf 10.5days <1 Non-VOC
1234ze (E) 16.4days <1 Non-VOC
1233zd (E) 20days 1 Non-VOC
*Volatile Organic Compound (VOC) status
Materials Must Meet Many Other Complex Requirements Before Acceptance
26Nov 6, 2019
Life Cycle Analysis (LCA) : Automobile Air Conditioning
0
500
1,000
1,500
2,000
2,500
3,000
3,500
134a1234yf CO
2134a1234yf CO
2
Phoenix
Tokyo
LCA
, kg
CO
2e
Source: T. Ikegami, K. Inui, K. Aoki(JAMA), 2008 SAE Alternative Refrigerant System Symposium, Phoenix June 10-12.
• Three refrigerants:– 134a– 1234yf– CO2 (R-744)
• Compact car – different climates• Cradle to grave analysis:
– Normal & abnormal leak rates– Service practice– End of life practice– Fuel consumption (& exhaust
emissions) for A/C operation• LCA: kg CO2 equivalent
– Direct contribution: refrigerant emission– Indirect contribution: CO2 exhaust
emission from fuel burned to run the A/C
27Nov 6, 2019
From The Website https://www.fluorineproducts-honeywell.com/climate-ticker/#
28Nov 6, 2019
Summary• Ozone layer has not fully healed yet, but it will recover due to HFC and
other non-ozone depleting technology development
• Greenhouse gas regulation is impacting HFC-user industries
• Multiple technology options are available to replace HFCs
• Technology choice should:
– Minimize total global warming impact, over the product life cycle
– Provide safety in use
– Be functional in the application
– Be economically viable
30Nov 6, 2019
Thank You