6.3 Fuel Types and Uses

What are subsistence fuels?

biomass fuel sources that are easily accessible (can be found and gathered by hand)

Subsistence fuels are usually used in what?

developing countries for heating fuel

Types of subsistence fuels

• Wood (and charcoal) / two most common fuel source in developing nations, is free/cheap

• Peat / is partially decomposed organic matter (often ferns or other plant) found in wet acidic ecosystems like bogs/moors and can be dried and used as biomass fuel

Wood and charcoal can cause what environmental problem?

deforestation and habitat loss

Coal formation comes from pressure…

of overlaying rock + sediment layered over centuries, transforming peat into coal through heat and pressure.

Peat is what forms..

coal

Order of energy density and quality for coal

lignite - bituminous - anthracite

lowest highest

The longer coal is pressurized by overlaying rock…

the more energy dense it becomes and the more value it will have as a fuel source.

Anthracite is the most..

valuable of coal due to more energy being released as fuel and having a higher carbon content than other types

More dense coal =

hotter/longer fire = more steam = more electricity to power turbine when coal is burned

Natural gas is formed from…

decaying remains of plants and animals (mostly marine) that are buried under layers of rock, converted by pressure into petroleum and natural gas over millions of years

Mostly methane is found on..

trapped petroleum deposits

Methane forms when…

oil is trapped in a porous sedimentary rock underneath a harder impermeable rock that lets gas escape

Natural gas is considered the..

cleanest fossil fuel

Natural gas produces

• ½ the carbon dioxide as coal when burned to generate electricity *less sulfur nitrogen oxide

• Produces no PM (ash/soot) *doesn’t worsen asthma or bronchitis

• Produces less SO and NO than coal or oil *NO MERCURY

Crude oil is also..

petroleum

Crude oil is decaying..

organic matter trapped under rock layers compressed into oil over time- FOSSIL FUELS

Crude oil is extracted by..

drilling a well through the overlaying rock layers to reach the underground deposit before pumping liquid oil out under pressure

Crude oil can also be recovered by

tar sands

Tar sands are a combo of

clay, sand, water, and bitumen

What is bitumen

it is a thick, sticky, semi solid form of petroleum (not liquid)

Extracting and using oil from sands is extremely..

energy and water intensive, often leading to environmental concerns.

Tar sands process

1) Lots of water heated (requiring energy) to create a steam that’s piped down into tar sand to melt the bitumen into liquid that can flow up pipe

2) Lots of water used for separation for the oil of all impurities (sand/clay) at refinery the entire process results in significant greenhouse gas emissions and land disruption

Crude oil (petroleum) is converted into lots of different products through this

fractional distillation

Process of fractional distillation

1) Crude oil is burned in a furnace and vapor presses into a column where different hydrocarbons separate based on boiling points, allowing for the collection of various fuels and petrochemical products

2) Hydrocarbons with lower boiling points gather at the top of the column while those with higher boiling points gather at the bottom

Different hydrocarbons used for different products

• Petroleum gas

• Gasoline (fuel for cars)

• Naphtha (used to make plastic)

• Jet fuel

• Diesel fuel

• Motor oil

• Bitumen (asphalt for roads)