Fossil Fuels - Chemistry for Engineers

Flashcards covering the classification, formation, chemical components, carbon content coefficients, and combustion processes of fossil fuels.

What is the general definition of a fossil fuel?

Buried combustible geologic deposits of organic materials formed from decayed plants and animals by exposure to heat and pressure in the earth's crust.

What is kerogen?

A complex waxy mixture of hydrocarbon compounds that is the primary organic component of oil shale, formed from ancient marine bodies before becoming a fossil fuel.

What process transforms kerogen into a fossil fuel?

Kerogen combined with pressure and heat turns into fossil fuel (coal, oil, or gas).

How is coal formed and what is its relative abundance?

Coal is a solid fossil fuel formed over millions of years by the decay, compaction, and heating of land vegetation; it is quite abundant compared to oil and natural gas.

What is natural gas and what is its primary chemical component?

Natural gas is a gaseous fossil fuel that is versatile, abundant, and relatively clean compared to coal and oil, mainly consisting of methane ($CH_4$).

What are the additional energy components found in raw natural gas?

Ethane, propane, butane, isobutene, and pentane.

What are the non-energy components contained in raw natural gas?

Carbon dioxide, nitrogen, hydrogen sulfide, and water.

What distinguishes wet natural gas from dry natural gas?

Wet natural gas contains hydrocarbons in addition to methane, while dry natural gas has gases other than methane removed.

What is oil (crude oil) and what is its usage level relative to other fossil fuels?

Oil is a liquid fossil fuel formed from the remains of marine microorganisms deposited on the sea floor, and it is the most widely used fossil fuel.

What occurred $300\text{--}400\text{ million years ago}$ in the formation of petroleum and natural gas?

Tiny sea plants and animals died and were buried on the ocean floor, where they were covered over time by layers of silt and sand.

What occurred $50\text{--}100\text{ million years ago}$ in the formation of petroleum and natural gas?

Plant and animal remains were buried deeper under sand and silt, and enormous heat and pressure turned them into oil and gas deposits.

Based on this reservoir diagram, what is the arrangement of Gas, Oil, and Water in an underground rock formation?

Gas is located at the top, Oil in the middle, and Water at the bottom layer.

What are the carbon content coefficients for Industrial Coal and Crude Oil?

Industrial Coal has a carbon content coefficient of $25.74$ Tg Carbon/QBtu and Crude Oil has a coefficient of $20.29$ Tg Carbon/QBtu.

What does a higher carbon content coefficient indicate?

A higher value indicates higher carbon emissions.

What chemical reaction occurs during the combustion of fossil fuels?

Carbon and hydrogen react with oxygen in air to form carbon dioxide ($CO_2$) and water ($H_2O$) in an exothermic process that releases heat.

How is electricity generated from fossil fuels in power plants?

Electricity is generated by transforming mechanical energy (heat) to electrical energy in a turbine or generator.