Lecture 17 | Fossil Fuels

Peak Oil, Fossil Fuel Formation, Biomass, Location of Coal/Natural Gas/Oil Formations, Extractions, Clathrates, Coal Burning & Pollution

Biomass

mass of some living organism

A tree can go from a 1g seed to over 100 kg as a massive tree. Where does this biomass come from?

co2, water, photosynthesis, thin air

Describe how primary producers make biomass:

e- from water and c from co2 to make glucose

How do carbohydrates like glucose store energy?

chemical bonds, more bonds = more potential energy

How can we tap into the energy stored in primary producers?

break bonds: eat plant material & use e, burn biomass and release heat

How can you increase the energy you get from eating or burning biomass?

break more bonds

What are two paths that biomass can follow after an organism dies?

decomposed and e goes to decomposer, gets buried and e locked away

What happens when biomass gets buried under sediment?

gets compressed, can turn into fossil fuels

Compression

packs a lot of chemical bonds into a smaller volume

When you compress biomass, the ____ changes, but _____ stays the same

volume, mass

What volume of leaves could 1 piece of coal contain?

a full room

How does compression make biomass more useful?

portable, energy-dense materials

How old is the biomass that formed the fossil fuels we use today?

350-500 million years

Where does most of the biomass in fossil fuels come from? Why?

plants, low trophic level, more primary producers than apex predators

What does the amount of compression that biomass experiences depend on?

how deep its buried, deeper = more compression

In order from most shallow to deepest, list the formation of fossil fuels that occurs on land:

plba: peat, lignite, bituminous coal, anthracite

Peat

few 100 feet down, soft, squishy, barely compressed

Lignite

brown coal, hard, not dense, few 1000 feet down

Bituminous Coal

nearly 1 mile down, very hard, dense, burns well

Anthracite

several miles down, very rare, extremely energy rich, under mountains

Which type of coal yields the most energy when burned (per size)? Why?

anthracite, more compression fits more bonds per size

Peat Formation Conditions

low temp, low pressure

Coal/Anthracite Formation Conditions

low temp, high pressure

Natural Gas Formation Conditions

high temp, low pressure

Oil Formation Conditions

high temp, high pressure

In the formation of fossil fuels, what does low temperature mean?

formed on land

In the formation of fossil fuels, what does high temperature mean? Why?

formed under ocean, closer to mantle & warmer

In the formation of fossil fuels, what does high pressure mean?

buried deeper, could be under mountain or far under ocean

Because oil and gas are compressed, they are also ____ ______

under pressure

How do compressed oil and gas relieve the pressure they’re under? Provide an example:

find ways to get to the surface, coal oil point

What are two ways oil and natural gas can get trapped in rock formations?

anticlines, transform faults

Anticline

upside down bowl, soft pore rock stuck beneath curved/hard cap rock

Transform Fault

two plates sliding past, cap rock slid over porous rock that traps oil & gas

What places do petroleum geologists look for to determine where to drill for oil & gas?

aged rocked, soft pore rock with cap rock on top

What are the two extraction methods to retrieve oil & gas?

primary production, enhanced production/recovery

Primary Production

sink a well, pump oil whatever you can, 20% recovery

Enhanced Production/Recovery

inject co2 or n2 to force oil towards pumping well, 60% recovery, costs more

Where are most of the oil formations, and who used the most oil?

middle east, NA & europe, developed

Natural Gas provides _____ energy than oil

less

What does higher compression lead to for natural gas?

longer c chains, more energy

Natural gas still emits CO2 when burned. Why is it considered cleaner than coal?

no nox, sox, or mercury

Hydraulic Fracturing (Fracking)

high pressure water & chemicals injected to burst fractures wider, makes pumping natural gas easier

What is a danger associated with fracking?

fracture cap rock, gas & chemicals leak into aquifers & drinking water

Methane Clathrates/Hydrates

gel-like deposits of methane gas trapped in water molecule cages

How and where do methane clathrates form?

hexagon lattice of water, methane fits in cage, specific temp & pressures in ocean

What is the issue with using methane clathrates?

unstable, release heat, chain reaction of destabilizing, methane bubble

Coal is the _____ and _____ fossil fuel used

most common, dirtiest

What three impurities does coal release, and what is their effects (4 things)?

sox & nox acid rain, mercury in aquatic food chain, particulate matter smog & breathing, co2 emissions climate change

Where are coal deposits commonly found?

north america, asia, europe

What is the most common coal types found in the US? Where is anthracite only found?

lignite & bituminous, anthracite in pennsylvania mountains

What are 3 technologies to treat coal pollution?

high efficiency filters, catalytic converters, flue gas desulfurization

High Efficiency Filter/Bag House Purpose

remove particulate matter

Catalytic Converter Reduction Purpose

turn nox into n2 and o2 gas

Flue Gas Desulfurization Purpose

combine sox, mercury, & limestone to make gypsum