LESSON 7_ FOSSIL FUELS Flashcards
- Is a chemical and biological form of energy.
- Refers to the remains of living things from previous geologic eras.
- An era is a unit of geologic time that lasted for hundreds of millions of years.
- Developed from the remains of ancient living things, mostly plants.
Fossil
3 main categories of fossil fuels:
- Coal
- Oil
- Natural gas
The different fossil fuels formed depending on the action of four factors:
- Organic Matter Source
- Heat
- Pressure
- Time
Origin of fossil fuels
Carboniferous period of the Paleozoic Era
- Means coal-bearing
- Occurred 359 million to 299 million years ago, which means that it lasted for about 60 million years.
- Was characterized by swamps where large tress, giant ferns, and many other plants thrived. Swamps are low-lying areas, saturated with water, either permanently or frequently
Carboniferous
- Refers to ancient life
- Occurred 541 million to 252 million years ago, lasting for about 289 million years.
Paleozic
- A black combustible rock made up of elemental carbon, hydrogen, oxygen, nitrogen, and varying amounts of sulfur.
- Formed from the remains of plants that once grew in swampsand adjacent forests millions of years ago.
- These organisms were then buried under oxygen-poor or anoxic conditions.
- Formed due to heat and pressure
Coal
4 Stages of Coal formation
- Peat (Decay of vegetative material)
- Lignite (Compressed peat)
- Bitumen (Compressed Lignite)
- Anthracite (Considered by some to be a metamorphic rock)
4 stages of Coal formation
(Decay of vegetative material)
- Is considered the precursor form of coal, contains less than 60% carbon and composed wholly of volatile matter.
- Left to itself, it burns like wood, gives less heat, emits more smoke and leaves a lot of ash.
Peat
4 stages of Coal formation
(Compressed peat)
- Also known as brown coal and is composed of 65-70% carbon and **53-63% volatile matter.*
- Undergoes Spontaneous combustion
Lignite
4 stages of Coal formation
(Compressed Lignite)
- A sedimentary rock composed of 70-86% carbon and 31-46% volatile matter.
- Calorific value is very high due to high proportion of carbon and low moisture.
Blutiminous coal
4 stages of Coal formation
(Considered by some to be a metamorphic rock)
- Deemed the highest form of coal due to its carbon content ranging from 86-98% with 3-8% volatile matter.
- Ignites slowly and burns with a nice short blue flame.
- Produce more energy among the different
types of coal.
Anthracite
- Comes from the Latin words petra which means “rock”, and oleum which means “oil”.
- It is a naturally occurring liquid composed of complex hydrocarbons, and is found in geologic formations underneath Earth’s surface.
- A fossil fuel derived from large quantities of microscopic aquatic organisms such as algae and planktons.
- The remains of these organisms remain settled to the sea or lake bottoms millions of years ago and were buried beneath fine sediments anoxic conditions.
- With increasing pressure and temperature due to continuous burial, the organic matter in these organisms transform into a waxy material known as kerogen and eventually into hydrocarbons through the process of catagenesis.
- Formed at around 50-150 degrees celsius
Petroleum
- The insoluble organic portion of sedimentary rocks.
- It is a waxy mixture of different organic materials (like algae and pollen) and is insoluble in organic solvents because of the high molecular weight of the compounds present.
Kerogen
- A hydrocarbon mostly made up of methane (CH4).
- Lighter than air and is highly flammable.
- Petroleum and natural gas migrate upwards and are sometimes stored within porous reservoir rocks, such as sandstone, until they become trapped by impermeable layer of rock to prevent further migration. This scenario gives rise to petroleum and natural gas deposits that are being extracted at present.
Natural gas
