David Au Georgia Department Agriculture August 22, 2019

1. David Au Georgia Department Agriculture August 22, 2019 Importance of Gasoline Volatility, Sulfur and Nitrogen reduction on Automobile Performance and Emission CONTROLS

2. Why talk about gasoline volatility? • Georgia EPD submitted a request in 2018 for the relaxation of gasoline RVP (Reid Vapor Pressure) from 7.8 to 9.0 psi in metro-Atlanta counties during the summer season. • EPA has approved the Georgia request and in the process of removing the 7.8 psi RVP requirement for Georgia gasoline • Relaxation may have significant economy and logistic advantages – one class RVP gasoline in summer • How does the RVP relaxation affect the environment?

3. What is Gasoline Volatility? • Gasoline vapors: Tendency to change from liquid to gasoline vapor at a given temperature. “Gasoline as a liquid does not burn – it is the vapors that the liquid gives off that burn” – needs vapors to start! • Volatility related to combustion engine performance: ease of starting, length of warmup period, acceleration, power, and roughness • Commonly measured parameter of volatility- Reid Vapor Pressure (RVP) • Environmental and health concerns – amount of gasoline vapors or emissions

4. Outline • Environmental and emission concerns: Too much emission? • VOC(volatile organic compounds, related to RVP),NOx, (nitrogen oxides): Ozone • SO2(sulfur dioxide), NOx: Acid rain, PM (particulate matters) • EPA: Sulfur, Nitrogen, VOC’s reduction programs • EPA and GDOA regulations on volatility and emissions • Gasoline volatility on automobile performance • Vapor pressure, Vapor lock protection, Air/fuel Ratio • Evaporation characteristics (Distillation); Driveability Index (cold start, warm up, acceleration, fuel efficiency) • Georgia EPD to propose a relaxation of RVP (from 7.8 to 9.0 psi) in summer season – why? current status

5. Pollutions/Emissions • Gasoline Vapors • VOCs (Volatile organic compounds); high vapor pressure, e.g. benzene, ethylbenzene, formaldehyde • Nitrogen - Nitrogen Oxides (NOx) • Fuel-bound nitrogen- account for up to 50% of the total NOx emissions • During the combustion at high temperature (excess air) • Sulfur - Hydrogen Sulfide, Sulfur Dioxide (SO2) • Unburnt Hydrocarbons (UHC), Carbon Monoxide Ozone, Acid Rain and Particulate Matter

6. What is Ozone? • Ozone (Trioxygen) • is an inorganic molecule with the chemical formula O3, made up of three oxygen atoms rather than the usual two oxygen atoms. It is a pale blue gas with a distinctively pungent smell. • Ozone formation: due to gasoline vapors and emissions • Good vs. Bad (Ground level) Ozone • Ozone depletion: Freon, chlorofluorocarbons, bromides – pesticides (future discussion)

7. OZONE FORMATION

8. Good Vs. Bad Ozone GOOD Stratospheric ozone is “good” because it protects living things from ultraviolet radiation from the sun. it absorbs the portion of UV light – short wavelength/high energy UV (200-300 um) Shrinking due to Freon, chlorofluorocarbons, bromides BAD Ground-level ozone is “bad” because it can trigger a variety of health problems

9. What is VOCs? • A volatile organic compound (VOC) is defined by EPA as any compound of carbon, excluding carbon monoxide, carbon dioxide, carbonic acid, metallic carbides and carbonates, which participates in atmospheric photochemical reactions – gasoline vapors • Hydrocarbon VOCs are harmful and usually grouped into methane and other non-methane VOCs such as benzene, polycyclic aromatic hydrocarbons (PAHs) • Volatile Organic Compounds (VOC's) are organic chemicals that have a high vapor pressure and easily form vapors at normal temperature and pressure.

10. What are Nitrogen oxides (NOx)? • NOx is a strong oxidizing agent and plays a major role in the atmospheric reactions with VOCs that produce ozone on hot summer days. • NOx is formed when nitrogen and oxygen in the combustion at the high temperatures in a flame. • Fuels containing significant amounts of fuel-bound nitrogen, fuel NOx can account for up to 50% of the total NOx emissions. • Preventing the production and release of nitrogen oxides during combustion - Removal of nitrogen oxides after combustion.

11. Acid rain is chemical reactions of sulfur dioxideand nitrogen oxides mixed with water, oxygen, and other chemicals to form acidic pollutants or particles (CORROSION)

12. What is Particulate Matter (PM)? • Complex reactions of chemicals of nitrogen oxides and sulfur dioxide (SO2) may produce “Acid Rain” or “Acid Particles.” Crude oil may contain up to 7.0% sulfur; Sour crude oil needs to be stabilized by having hydrogen sulfide gas removed (injecting inert gases) before being transported • Volatile particles such as sulphates, nitrates and organic carbon (HC) may also be formed in engine exhaust due to partial combustion of the fuel. • Small particles less than 10 micrometers in diameter pose the greatest problems, because they can get deep into your lungs, and some may even get into your bloodstream. • PM is defined as a mixture of solid particles and liquid droplets found in the air, such as soot, or smoke, UHC • EPA regulates inhalable particles (less than 10 microns)

13. Particulate Matter - Size Matter(< 10 microns) • PM10: inhalable particles, with diameters that are generally 10 micrometers and smaller; and • PM2.5: fine inhalable particles, with diameters that are generally 2.5 micrometers and smaller. The average human hair is about 70 micrometers in diameter – making it 30 times larger than the largest fine particle. Particles of sand and large dust, which are larger than 10 micro, are not regulated by EPA. 

14. EPA Clean Air Programs • Sulfur reduction- sulfur such as sulfate, H2S, SO2, • NOx, PM, CO reduction – tailpipes emissions, catalytic converters • Air Toxics Standards for Gasoline - limits the content of toxic chemicals. Benzene (< 0.62%) and other hydrocarbons such as 1,3-butadiene, formaldehyde, acetaldehyde, acrolein, and naphthalene • Reformulated Gasoline (RFG) - gasoline that meets more stringent specifications, reducing emissions of the pollutants that contribute to ground level ozone and PM pollution. • Renewable fuel standards – 19.9 billions gallons of biofuels to be consumed in 2019 – reduce CO and less dependent on foreign oils • Low Reid Vapor Pressure (RVP) - specially blended gasoline that evaporates less at higher temperatures than regular gasoline in the hot summer months (RVP season) • Gasoline vapor recovery programs (Stages 1 and 2) • Stage 1 (recovery of vapors from UGT to the trucks, then to terminals • Stage 2 (recovery of vapors from automobile tanks to the UGT)

15. Sulfur – PM and SO2 Reductions • When those fuels are burned, sulfur is emitted as sulfur dioxide (SO2) or sulfate particulate matter. • Tier 1 standards (1990, Clean air acts) – 83% sulfur in diesel reduction: 3000 ppm to 500 ppm • Tier 2 standards (starting 2007) – 97% sulfur reduction diesel: 500 to 15 ppm • Tier 3 standards (starting 2017) - 70 percent tighter particulate matter standard (sulfur in gasoline limited to 10 ppm – 60% reduction) From 30 to 10 ppm • Tier 4 standards - Nonroad, locomotive and marine (NRLM) diesel: 3000 ppm to 15 ppm – 99.5% reduction • Global: marine diesel (2020): 35,000 to 5000 ppm; • Global: diesel (2015): 100 ppm

16. FSU: Former Soviet Union Countries * Data from OPEC

17. Sulfur • Inorganic sulfur (can be separated by physical mean): pyrites, element sulfur, Fe2S3 • Organic sulfur (not easy to separate without chemical reaction): Thiophene, Dibenzothiophene Light Sweet Crude: total sulfur less than 5000 ppm (0.5%) • Designated by New York Mercantile Exchange • One step desulfurization process, easy to refine • May not poison the hydrocracking catalyst • Sour crude oil needs to be stabilized by having hydrogen sulfide gas(H2S) removed from it before being transported by oil tankers • Libya, Venezuela

18. Removal of Nitrogen Oxides After Combustion • Nitrogen is the most difficult and expensive to remove.Pyridinic nitrogen removal is challenging because it requires 1 double bond and one single bond to be broken. – Strong covalent bonds • Nitrogen oxides (about 50%) form during the combustion when fuels are burned at high temperatures • Idea of a catalytic converter is to try to eliminate the carbon monoxide, nitrogen oxides and unburnt hydrocarbons by reacting them with plenty of oxygen on a platinum catalyst.

19. Catalytic Convertor Gasoline engine • Two-way (Oxidation) • Oxidation of carbon monoxide to carbon dioxide: 2 CO + O2 → 2 CO2 • Oxidation of hydrocarbons (unburnt and partially burned fuel) to carbon dioxide and water • Three Way (Oxidation and Reduction) • Reduction of nitrogen oxides to nitrogen (N2) • 2 CO + 2 NO → 2 CO2 + N2 • hydrocarbon + NO → CO2 + H2O + N2 • 2 H2 + 2 NO → 2 H2O + N2 • Effective when the engine is operated within a narrow band of air-fuel ratios near the stoichiometric point (14.6 to 14.8), such that the exhaust gas composition oscillates between rich (excess fuel) and lean (excess oxygen).

20. Diesel Engine/Diesel Exhaust Fluid (DEF)/ Particulate Filter PM and NOx emissions can be reduced 99% compared to 1996 levels

21. Selective Catalytic Reduction (SCR) – REMOVE NOX. This works by combining the exhaust gases with ammonia (urea or DEF, diesel emissions fluid) and passing this mixture over a catalyst. Forming nitrogen Diesel Particulate Filter (DPF) - This works by using a mechanical filter to trap soot particles after they have been partially oxidized by a catalyst. At certain intervals during operation, the trapped particles are incinerated. Exhaust Gas Recirculation (EGR) - This works by recirculating a small amount of cooled exhaust gas back into the combustion chamber. This reduces the combustion temperature and effectively reduces the production of Nox (low temp, lower the amount of Nox)

22. Low RVP gasoline and EPA vapor recovery systems Low vapor pressure (7.8 psi) in Atlanta Fuel Volatility area during the RVP season • Cherokee, Clayton, Cobb, Coweta, DeKalb, Douglas, Fayette, Forsyth, Fulton, Gwinnett, Henry, Paulding, and Rockdale Vapor recovery systems • Stage 1: vapor recovery from underground (UGT) tank to terminal • Stage 2: vapor recovery from automobile to UGT (discontinued in Georgia)

23. EPA Stage 1 Vapor Recovery System Expect to capture 5 million tons annually of toxic air pollutants Depending on the facility sale volume, 20 Georgia counties are required to implement this system by Georgia EPD

24. EPA Stage 2 Vapor Recovery System No Longer required in Georgia EPA no longer required stage II vapor recovery systems to meet federal the ozone standard

25. Georgia Gasoline Classification Based on Volatility • Designated by Federal EPA • Atlanta Fuel Volatility Area (13 metro-Atlanta counties): AA-2, AA-3 (What does AA-2 mean?) • Summer: A-2, A-3 • Winter: D-4 (high vapor pressure) • Spring and Fall: C-3

26. Permissible Volatility classes may be sold during the month Determined by EPA based on the Doner Report AA-2 Aug., Sept. 1-15 (13 metro Atlanta Counties) AA-3 June, July (13 metro Atlanta Counties) A-2 Aug., Sept. 1-15, A-3 June, July C-3 March, April, May, Sept. 16-30, Oct., Nov. D-4 Jan., Feb., Mar., Nov., Dec.

27. What is Vapor Pressure? • Vapor Pressure is the pressure where the first bubble of vapor is formed at a given temperature and at normal pressure. Volatile liquid fuel - a fuel that is liquid at atmospheric pressure and has an RVP higher than 2.0 psi • Reid vapor pressure (RVP) is a common measure of the volatility of gasoline. It is defined as the absolute vapor pressure exerted by a liquid and any dissolved gases/moisture at 100°F at normal atmospheric pressure • Gasoline vapors contain up to 60% butane and 20% pentane. Most of the gasoline RVP is provided by propane, butane, and pentane. Butane is blended in various amounts to adjust RVP - butane 52 psi RVP • #2 Diesel RVP = 0 psi; #1 diesel RVP = 0.03 psi

28. Environmental vs. Performance Lower emissions do not necessary provide a better engine performance Is it enough vapors to start or run the car?

29. Engine Performance • Gasoline as a liquid does not burn – it is the vapors that the liquid gives off that burn. • During the cold, winter months, fuel will be more volatile. This helps good "cold" start and warm-up performance. During the hot summer months, the fuel tends to be less volatile. This will help to minimize the incidence of vapor lock and hot driveability problems. • Fuel properties must be balanced to give satisfactory engine performance over an extremely wide range of operating conditions • According ASTM and EPA, there are four parametersused to control volatility limits, vapor pressure, distillation (boiling point range), vapor liquid ratio, and driveability index.

30. Gasoline Volatility: 1) Distillation (boiling point range), 2) Vapor pressure, 3) Vapor/Liquid ratio and 4) Vapor protection class If the end-point temperature exceeds the ASTM maximum requirement (437◦F), it is usually because of the presence of a distillate fuel such as No. 2 diesel. ASTM D5188 1 psi waiver with 9 to 10% ethanol

31. Distillation ParametersASTM D86 Method (Atmospheric) • The 10 percent evaporated temperature is directly affected by the seasonal blending of the gasoline. This temp. must be low enough to provide easy cold starting, but high enough to minimize the vapor lock and hot weather Driveability problems. • The 50 percent evaporated temp. must be low enough to provide good warm-up and cool weather Driveability without being so low as to cause to hot Driveability and vapor locking problems. This greatly affects fuel economy on short trips. • The 90 percent and end-point evaporation temperatures must be low enough to minimize crankcase and combustion chamber deposits, as well as spark plug fouling T70 can be an indicator for the amount of aromatics (SMOKE)

32. Vapor Lock • Unexpected cold days in the ‘hot summer month' fuel containing low RVP • Sluggish, roughness, warm up and accelerate problems (Not enough vapors) • Unexpected hot days in the 'cold winter month' fuel containing high RVP • Vapor lock (Too much vapors)

33. Gasoline Vapor Lock • Six Vapor Lock Protection Classes (insure proper start-up and warm-up) • Based on Temp of vapor liquid ratio @ 20 to 1 • Measure by ASTM D5188 method • Numeric (1-6 classes), based on geographically and seasonal. Class 6 is the most volatile • Controlled by blending butane

34. Volatility Waiver (9-10 Vt% of Ethanol) Georgia Regulations 20-10-0.1 allow: • T50 minimum distillation temperature of 150◦F for all volatility classes (reduced from 177F) • Vapor pressure 1 psi higher • V/L=20 minimum temperature of 120◦F for volatility classes AA-2 and A-2, 113◦F for classes AA-3, A-3, and C-3, and 107◦F for class D-4

35. Relax RVP for Summer Gasoline- Why? • One type of summer gasoline through the RVP season in entire Georgia • RVP of 9.0 psi for the entire RVP season • Significant economy and logistic advantages • According to federal EPA, Georgia is currently in attainment for all PM, SO2, NO2, CO, and Pb (Lead). Relaxation of RVP requirement will have little to no impact on emissions of these pollutants. PM and NOx emissions had been reduced 99% compared to 1996 levels.

36. Relax RVP for Summer Gasoline- Why? • EPA Tier 2 standards were promulgated in 2000, which required vehicle manufacturers to reduce the overall tailpipe emissions of CO, HCHO, NOx, VOCs, and (PM) by 88% to 95%;-- 97% sulfur reduction in diesel fuels • EPA Tier 3 standards were started in 2017 and the standards for light duty vehicles require reductions of about 80% in tailpipe emissions of non-methane organic gases and nitrogen oxides and of about 70% in tailpipe emissions of particulates. 60% sulfur reduction in gasoline • EPA Tiers 4 standard began in 2012 and the standards require 97% sulfur reduction in nonroad, locomotive and marine (NRLM) diesel fuels. PM and NOx emissions had been reduced 99% compared to 1996 levels. • Stage 1 and Stage 2 vapor recovery systems • Performance of catalytic converters. • Pb (lead) fuel has been banned for passenger vehicles since in 1974

37. Reasons to Relax RVP for Summer Gasoline The amount of NOX reductions obtained from the school bus and locomotive retrofits are more than what is needed to compensate for the small amount of NOX and VOC increases due to relaxation of the federal RVP requirement. • The maximum of NOx and VOC emissions increases 40.2 tons per year associated with relaxation of the 7.8 psi RVP requirements. The annual NOx emissions decreases due to the locomotive and school bus conversion is 46.0 tons per year. The downward trend in emissions reflected in the NOX and VOC attainment inventories shows that there would be sufficient safety margins.

38. Timeline of RVP relaxation in Georgia 13 counties • 9.0 RVP gasoline for the entire state of Georgia in summer season; Requested by Georgia EPD on August 15, 2018 (Completed) • Published by Federal EPA in Federal Register on Feb 12, 2019, and April 22, 2019 (Completed) • First commenting to EPA must be received on or before March 14, 2019 – accepting and approving the GEPD data and Georgia state (SIP) request (Completed) • Second commenting – Removing the 7.8 psi Federal requirements – before June 13, 2019 (3 comments) • Rule making (In-progress)