Transcript File
Fuels Roger Bortignon 1 Oil Industry Oil Refineries: transform crude oil into mainly gasoline The world consumes 80,000,000 barrels of crude oil each ammonia, antiseptics, bubble gum, crayons, denture adhesive, eyeglass frames, fertilizer, floor polish guitar strings, heart valves, ice chests, insect repellant, life preservers, liquid detergent mascara, paint, pingpong paddles, plastic beverage containers, roller-skate wheels, sneakers synthetic fibers, telephones, volleyballs… 2 What is crude oil? Crude oil is comprised of… 1) Carbon - 84% 2) Hydrogen - 14% 3) Sulfur - 1 to 3% 4) Nitrogen - less than 1% 5) Oxygen - less than 1% 6) Metals - less than 1% 7) Salts - less than 1% a mixture of crude oil, water and sand about 2 minutes after it has come out of the North Sea… 3 Alberta Oil Sands 4 Offshore Oil and Gas Potential in British Columbia 5 Fractional Distillation • Crude oil is heated to ≈ 600°C 6 Fractional Distillation • heated vapors rise into different chambers via “bubble caps” • liquid & molecules can either bubble thru or condense • temperatures greatest at bottom of tower 7 crude oil enters here… 8 At the top of the column… • light molecules • low boiling points • gases & very runny liquids • very volatile • highly flammable • light colour At the bottom of the column... • heavy molecules • high boiling points • thick, viscous liquids • low volatility • not very flammable • dark colour 9 10 Cracking Cracking: breaks large HC molecules into smaller ones. • Types of cracking processes… 1) thermal cracking uses high heat to break up molecules 2) catalytic cracking uses a platinum catalyst to combine naphtha into gasoline blending components 3) hydrocracking adds hydrogen under high pressure – produces a liquid hydrocarbon 11 Polymerization Polymerization is the opposite of cracking. • this process combines smaller fractions into larger ones • natural gas & waste gas is condensed into high octane liquids used in blending gasoline 12 13 Gasoline volatility: how easily the gasoline turns to a vapor • winter blend: fuel vaporizes at a lower temperature • summer blend: fuel vaporizes at a higher temperature reduces “vapor lock” implications? 14 Compression Pressure • higher compression ratio = more torque & BHP • higher compression ratio = easier for fuel to self ignite 15 Abnormal Combustion Preignition 16 Octane rating: Octane reflects a fuel’s ability to combat “knock” how much the fuel can be compressed before it spontaneously ignites • high octane fuels = harder to ignite / burn slower • low octane fuels = burn faster • 2 types of octane numbers Motor Octane Number (MON) high load test Research Octane Number (RON) low load test octane number at the pump is (R+M)÷2 17 Octane Boosters • TEL: tetra-ethyl lead: used 1920’s – 1960’s • TML: tetra-methyl lead lead absorbs heat = slower combustion early 1970’s lead phased out Unleaded fuels may include… • MMT: methylcyclopentadienyl manganese tricarbonylis banned in Canada since 2004 • aromatic HCs such as xylene & tolulene • propane & butane ethanol: drinkable alcohol – up to 10% added methanol: can be produced from petroleum products or… non-petroleum feedstocks; coal, can damage fuel system parts MTBE: methyl ether ETBE: ethyl ether = oxygenated fuels 18 Octane • 87 octane fuel is… 87% iso-octane & 13% heptane 19 Diesel Fuel • less volatile than gasoline • higher flash point (safer) The flash point is the lowest temperature at which the vapors above a flammable liquid will ignite on the application of an ignition source burns slower • contains more heat energy than gasoline • winter fuel: #1 - light diesel, flows easily, less power • summer fuel: #2 - the most commonly used • “low sulphur diesel” contains <500 parts per million sulphur • since 1998, all on-road diesel fuel in Canada must be LSD • June, 2006 : ultra-low sulphur 15ppm • additives prevent paraffin wax formation at low temperatures • rated by cetane number 20 Diesel Fuel’s Cetane Number • Cetane: colorless liquid HC with very good ignition qualities • cetane ratings range from 40 to 50 • higher cetane number = ignites faster • high speed diesels require higher # - Why? • the percentage of cetane determines the CN • opposite of octane rating higher octane # resists self-ignition higher cetane # promotes self-ignition 21 • comparison of gasoline’s octane rating & diesel’s cetane rating 22 Liquefied Petroleum Gas (LPG): • made mainly of propane & blended with other components • 2% of vehicle fossil fuel usage in Canada • a vapor unless cooled or pressurized (> -42°C = vapor) • LPG is stored in liquid form under pressure (≈200psi) in a steel tank • LPG vapor is heavier than air implications? • no appreciable loss in HP (compared to gasoline) • burns clean – few deposits oil, spark plugs, combustion chambers stay clean/carbon-free • can be a dual-fuel system • few noxious fumes – great for warehouses • 82,000 BTUs compared to 120,000 BTUs for gasoline • must hold a provincial license to work on the high pressure side • high octane rating (104 or higher) implications? • requires > spark plug voltage to fire (has higher ignition temperature) 23 LPG Operation / Components 24 LPG Converter 25 LPG Converter 26 Compressed Natural Gas CNG… • made up mainly of methane (≈ 95%) • .25% of vehicle fossil fuel usage in Canada • the tank stores natural gas vapor at 3,000 PSI • low tank capacity = short driving range • limited number of refueling stations • can be dual-fuel system • 22,000 BTUs • can be used on diesel engines (diesel fuel = 15% to 35%, remainder is CNG) • octane rating 120 implications? • must be licensed to work on the high pressure side implications? 27 CNG Fuel Injection System 28