Chapter 15 Energy from organic fuels. The Need for Energy -fuel: any substance from which energy is obtained. -Examples:? -How have things changes? -Organic.

Chapter 15Energy from organic fuels

The Need for Energy- fuel: any substance from which energy is obtained.

- Examples:?- How have things changes?- Organic fuels: contain carbon compounds, examples:- Hydrocarbon: compounds composed of only hydrogen and

carbon, example: methane (a lot of them end in “ane”- Methane, Ethane, Octane…. The octane rating of gasoline is

derived from a formula based on the amount of energy contained in the gas compared to pure iso-octane.

Butane isomers: same number of atoms, different structure.

- Organic fuels often contain other chemicals (the bad part usually for us anyhow), example: sulfur or lead

- Called impurities, many contribute to pollution.

Fossil Fuels- When organisms die, not all of the energy they had stored

was released.- When buried, and you add pressure, typically the organisms

energy is not loss.- Therefore: fuels derived from the remains of organisms that

lived long ago are fossil fuels. Examples: coal, petroleum, and natural gas.

Coal- Generated by organisms that died, covered in sediment, and with added pressure and heat

formed coal.- Chemically changed, and water removed (via pressure) become solid rock (coal)- Over time, hydrogens and oxygen's are removed, concentrating the carbon

(concentration of coal is directly related to the amount of energy available).- This concentration is how we categorize different types of coal materials.

Peat- Not technically a type of coal- Lowest value of energy available- High water content, low percent of carbon- First stage of coal formation- Looks kind of like decaying wood- The youngest of these categories- Gives off a large amount of smoke (due to high water concentration)

Lignite- Second stage of coal formation- Soft, brown coal composed of about 40% carbon- Burns quickly, very little smoak- Must be mined (peat does not have to be mined)

Bituminous Coal- Soft coal, 85 % carbon- Must be mined- Even more pure, burns hotter- Used by many power plants- Most abundant coal mined in US

Anthracite - Purest coal, 95% carbon- Shiny, black, often deeper underground than any other- Burns the hottest, least amount of smoke- Most expensive to acquire as well.

Petroleum - crude oil, and a liquid fossil fuel- non-renewable- Formed from microscopic protists, plants, and animals- Millions of years to form- Trapped in pocked beneath nonporous rock (with water and natural gas)- Can be under very high pressure (hence the term “gusher” when drilled into it.- Worlds most important resource.- Used to make a variety of products after being refined

- Heat homes- Produce electricity- Grease and lubricants- Asphalt for roads- Many types of plastics

Natural Gas- Often found trapped above petroleum pools- Mostly gaseous hydrocarbons- Methane is the primary- Others include: propane, nitrogen, and helium- Used instead of coal or oil because it burns cleaner (stoves, heaters,

etc…)- Really good because it does not have to be converted to electricity,

can be burned directly- Because of this, more efficient and less expensive to use- Often NG is considered a waste product at the oil platform and is

burned off.

Other organic fuelsBiomass Fuels (is a fuel formed from the products of living organisms)Wood- Still relied on heavily in developing nations- Advantages: renewable- Disadvantages: lots of smoke that is high is carbon dioxide, tree reduction can cause more

erosion.Garbage- About 2/3 of the material in garbage can be burned.- Some cities in the US already take advantage of this (using the heat to generate steam, thus

produce electricity)Methane- “swamp gas”- Decaying garbage dumps also produce methane (both are being harvested and used same

ways as natural gas)- Cows are the number one releasing agent of methane (both ends) but this is much harder to

use.

Alcohol- bioconversion: converting organic materials into fuels- Sugarcane and corn are used to make alcohol.- Ethanol is the primary alcohol being produced right

now- Good: renewable- Bad: not as much energy available as from regular gas- Gasohol: mixture of 4 parts gasoline to one part

ethanol.