Fossil Fuels Chapter 19. .

Fossil Fuels

Chapter 19

http://www.anwr.org/gallery/pages/03-ANWRtoUSmap.htm

1. Natural Gas• What it is:

– Mixture of methane (50-90%), heavier hydrocarbons (ethane, propane, butane) and small amounts of H2S (highly toxic)

• Properties:– Highly flammable; transportation difficult. Done in pipelines– Cleanest burning fossil fuel

• Methane is dried, cleansed of H2S, pumped in low pressure lines nationally.

• Heavier gases are removed as liquefied petroleum gas (LPG) for use in rural areas.

Natural Gas Distribution

Hydraulic Fracturing

• How: – Pumping water & chemicals under high

pressure underground to force natural gas/petroleum to surface

• Problems: – Possible groundwater contamination

– CH4 released

– Release of Fracking Chemicals

http://en.wikipedia.org/wiki/File:HydroFrac.png

How Long Will Natural Gas Last?

• At current consumption rate, factoring in undiscovered reserves, approximately 125 years.

• Including unconventional sources, 200-325 years

2. Coal• What is it:

– Solid fuel formed from plant matter during Carboniferous period, 360-285 million years ago.

• C content increases, water content decreases over time

• Ranked according to energy content

TypeEnergy Content (megajoules/kg)

Location in US

1. Anthracite 30-34 PA

2. Bituminous 23-34 Appalachia, Midwest, West

3. Subbituminous 16-23 West

4. Lignite 13-16 Gulf Coast, No. Great Plains

• Half is acquired through Strip-Mining (Surface Mining)• Acid Mine Drainage:

• rainfall reacts with exposed rock, reacts with sulfides, produces sulfuric acid.

• Processed to remove much sulfur before burning

• Uses of Coal:– converted into synthetic oil or gas. – Mostly used by power plants to create electricity (60%

of electricity produced). – Transported by train and coal slurry pipelines (uses

more water).

Open Pit Mining: digging at the surface to extract ore

http://en.wikipedia.org/wiki/Strip_mining#Strip_mining

Coal Surface Mining in Wyoming

Pollution & Coal• Burning releases mercury into env.• Takes a great deal of water; expensive, heavy

environmental impact • Production of NOx and SOx• Particulate Ash

• Treatment--Scrubbing – calcium carbonate-rich materials are injected into the gases

produced from burning coal, producing hydrated calcium sulfite as sludge.

– Disposal issues.

How Long Will Coal Last?

• At current consumption, 225 years. If usage rises 2%/yr, 65 years.

• Believed to be unidentified reserves projected to last 900 years.

3. OIL!• Petroleum (crude oil):

– thick liquid consisting of hundreds of combustible hydrocarbons.

• Impurities

– sulfur, oxygen, nitrogen & other impurities.

• Formation – decomposition of organic matter (mostly plant) – extreme pressures & temperatures – millions of years

• Usually dispersed throughout pores in rocks.

Oil Recover: 3 Stage Process• Primary:

– Drilling a well, then remove oil that flows into the well.

• Secondary: – Pumping water under high pressure into a nearby well,

forcing oil out, pump up to surface,– remove water from oil and reuse the water for recovery.

• Tertiary: – Use of superheated steam, CO2 or detergent to dissolve oil,

then removed from that. – Large amounts of energy needed (~1/3 barrel for every barrel

produced)

• Production clip

Fractional Distillation

• Separating the components that make up crude oil.

• Uses boiling points of the various fractions

64% in the Middle East;

26% in Saudi Arabia alone

Oil Facts

• US uses 30% of crude oil extracted; 68% for transportation

• $130.00 per barrel on 6/6/08• $48.92 per barrel 4/22/09• $91.58 per barrel 4/25/13 • 1 barrel petroleum = 42 gallons

Just How Much Is There?• Resource:

– A concentration of material that is economically feasible to extract, now or in the future.

• Reserve: – Portion of the resource

that can be extracted now, economically & legally.

Reserves…

• Production of reserves expected to peak between 2010 and 2030. Peaked in US in 1975.

• Undiscovered supplies may extend it 20-40 years.

Other Sources of Oil

• Oil Shale: fine-grained sedimentary rock containing kerogen. – Distilled to form shale oil. – Potentially recoverable from CO, UT, WY. – Generally very low grade, takes much energy.

• Tar sand: mixture of clay, sand, water & bitumen (thick, high sulfur oil). – Most lie below earth’s surface; those close can be mined. – Largest deposits in Canada, UT, Venezuela, Colombia, Russia.

Hubbert’s Prediction for Peak Oil Production

http://en.wikipedia.org/wiki/File:Hubbert_peak_oil_plot.svg