S.1 Non-Renewable Energy

Non-renewable energy refers to the energy resources that occur naturally but depleted with time as they are mined and utilized to meet the ever increase in global energy demands

Types of non-renewable energy sources are derived from gas, liquid or solid fossil fuel such as diesel, gasoline, heating oil, distillate, coal, natural gas

Nuclear energy is also classified as non-renewable energy

Fossil Fuel Source

P1.1 Acknowledgements

1. Azhar A. A., Normah M.G., Sanjayan V. , Faizal B.H.

2. Universiti Teknologi Malaysia ( www.fkm.utm.my/~asialink2006/ )

P1.2 Literature

Author: Sybil P. Parker, 1981 Title: “Encyclopedia of Energy” Publisher: McGraw-Hill Book Co.

Author: Cutler J. Cleverland, Christopher G. Morri s, 2004 Title: “Encyclopedia of Energy” Publisher: Elsevier Science Ltd.

Author: Attilio Bisio & Sharon Boots, 1996 Title: “Encyclopedia of Energy and the Environment” Publisher: John Wiley & Sons Publishing Inc.

Author: Myer P. Kutz, 2005 Title:“Energy and Power” Publisher: John Wiley & Sons Inc

Author: Schipper Lee, 2006 Title: “Energy Efficiency and Human Activity: Past Trends and Future Prospect” Publisher: Cambridge University Press

Author : Trinnaman, 2004 Title: “2004 Survey of Energy Resources” Publisher: Elsevier Science Ltd.

Author: Frank Kreith, 2007 Title: “Energy Conversion” Publisher: CRC Pr I. Llc

Some of the materials for this chapter are extracte d from the following websites: http://auto.howstuffworks.com/engine.htm

http://www.acdlabs.com/iupac/nomenclature

http://www.answers.com/topic/oil-refinery-1

http://www.americanenergyindependence.com/synthetic fuel.html

http://www.astm.org

http://en.wikipedia.org/wiki/Greenhouse_gas

http://www.sizes.com/units/cetane_number.htm

http://www.dieselnet.com/standards/

http://www.tuninglinx.com/html/octane-rating.html

http://www.taftan.com/thermodynamics/HVALUE.HTM

http://chemistry.about.com/library/glossary/bldef53 3p.htm

http://www.windows.ucar.edu/tour/link=/earth/Atmosp here/smog.html

http://www.britannica.com/eb/article-9026722/cracki ng

http://www.britannica.com/eb/article-9063032/reform ing

http://www.bydesign.com/fossilfuels/links/html/oil/ oil_find.html

http://www.britannica.com/eb/article-9110442/coal

http://www.britannica.com/eb/topic-123030/coalifica tion

http://waterquality.montana.edu/docs/photo/coalific ation.shtml

http://www.eia.doe.gov/kids/energyfacts/sources/non -renewable/coal.html

http://resourcescommittee.house.gov/subcommittees/e mr/usgsweb/photogallery

http://www.worldcoal.org/pages/content/index.asp?Pa geID=104

http://www.eia.doe.gov/oil_gas/natural_gas/info_gla nce/natural_gas.html

http://www.naturalgas.org/overview/background.asp

http://r0.unctad.org/infocomm/anglais/gas/market.ht m

http://flatplanet.wikispaces.com/Group+11+Fossil+Fu els+and+Sustainable+Energy

P1.3 Prerequisites

Some prior knowledge of chemistry and thermodynamic s (undergraduate level) are required to assist in the understanding of the content of this unit.

P1.4 LU and TU

Learning Units: 9 hours

Teaching Units: 3 hours

Explanation: Learning Units (LU) correspond to estimated number of hours for self-learning. Teaching Units (TU) correspond to estimated number of hours for te acher to present the material.

S.2 Educational Objectives

On completion of this chapter, you will be able to :

1. Understand the various types of fuels classified as non-renewable energies

2. The source of the fuels

3. The energy potential of the fuels and their cons tituents

4. Method of synthesis

5. Utilization of the types of non-renewable energy

S.3 Fossil Fuel

A fossil fuel is formed in the ground by chemical and physical changes in plant (mainly) and animal residues under high temperature and pres sure over geological time periods. The major fossil fuels are coal, petroleum, and nat ural gas. Petroleum products, such as fuel oils, are often included among the fossil fuel . Peat is thought to be an intermediate stage of most coals.

A fossil fuel can either be a solid, liquid, or ga seous fuel material

It consist mainly of carbon and hydrogen; the prop ortion of carbon is largest in coal and smallest in natural gas

Carbon and hydrogen (and their compounds) when bur nt in air will result in the formation of various exhaust gas products

Crude oil is separated into fractions by fractional distillation

Example of an Inland Oil Well

P3.1 Fractional Distillation

Crude oil is separated in fractions by a process called

fractional distillation

Source

See the explanation

P3.1.1 Explanation of Fractional Distillation

Figure shows a distillation process i.e. the most c ommon form of separation method used in petroleum refineries , petrochemical and chemical plants and natural gas processing plants. In many situations, the distillation is ope rated at a continuous steady state. Feedstock is always being added to the distillation column and products are always being removed. Unless the process is disturbed due to cha nges in feed, heat, ambient temperature, or condensing, the amount of feed bein g added and the amount of product being removed are normally equal. This is known as continuous, steady-state fractional distillation.

The distillation towers have liquid outlets at inte rvals up the column which allow for the withdrawal of different fractions or products having different boiling points or boiling ranges. The "lightest" products (products with the lowest boiling point) exit from the top of the columns and the "heaviest" products (those with the highest boiling point) exit from the bottom of the column.

For example, fractional distillation is used in oil refineries to separate crude oil into useful substances (or fractions) having different hydrocar bons of different boiling points. The crude oil fractions with higher boiling points:

S.4 Hydrocarbon

The classifications for hydrocarbons defined by IUPAC nomenclature of organic chemistry are as follows:

1. Saturated hydrocarbons (alkanes) are the simples t of the hydrocarbon species and are composed entirely of single bonds and are satur ated with hydrogen; they are the basis of petroleum fuels and are either found as li near or branched species of unlimited number. The general formula for saturated hydrocarbons is CnH2n + 2 (assuming non-cyclic structures).

2. Unsaturated hydrocarbons have one or more double or triple bonds between ca rbon atoms. Those with one double bond are called alkenes , with the formula C nH2n (assuming non-cyclic structures). Those containing triple bonds are called alkynes .

3. Cycloalkanes are hydrocarbons containing one or more carbon rin gs to which hydrogen atoms are attached. The general formula fo r a saturated hydrocarbon containing one ring is CnH2n

4. Aromatic hydrocarbons have at least one aromatic ring

Hydrocarbons can be gases (e.g. methane and propane ), liquids (e.g. hexane and benzene ), waxes or low melting solids (e.g. paraffin wax and naphthalene ) or polymers (e.g. polyethylene , polypropylene and polystyrene ).

Oil shale contains combustible material derived from fossiliz ed plant residues; the oil obtained by heating the shale is generally regarded as a synthetic fuel (or synfuel ) rather than a fossil fuel

Largest source of emissions of carbon dioxide (CO 2) is when burning the fossil fuel by humans. Under excessive fuel combustion unburned hy drocarbon (HCs) and

particulates will be the undesirable combustion by products that pollutes the environment

CCaaHHbb ++ ((aa++bb//44))((OO22++33..777733NN22)) ⇒⇒ aaCCOO22 ++ ((bb//22))HH22OO ++ 33..777733 ((aa++bb//44)) NN22

[Note: a and b are number of atoms for carbon and hydrogen in the hydrocarbon fuel]

Chemical reaction between a hydrocarbon fuel and air

S.5 Fuel Oil

The term distillate is usually applied to liquids boiling at temperatures higher than about 180 oC, which is above most of the gasoline range. Above the range, kerosene , diesel , industrial fuel oil, lubricating oil, paraffin wa x and asphalt are produced.

Petroleum distillates are commonly classified as li ght, medium (middle or intermediate), and heavy.

Each type of fuel has its own energy content (See t he related table and explanation ) Fuel or heating oil as classified by the American Society for Testing and Materials

(ASTM), divides fuel oils into the following six categori es, based on the type of burner for which the oil is suitable.

1. No. 1 Heating Oil – a light distillate of relatively high volatility and low viscosity

2. No. 2 Heating Oil - a medium distillate

3. No. 4 Fuel Oil - either a heavy distillate or a light residual oi l

4. No. 5 Fuel Oil (Light) - a medium residual oil, somewhat more viscous than No. 4 Fuel Oil

5. No. 5 Fuel Oil (Heavy). - a medium residual oil more viscous than No.5 Fue l Oil (Light)

6. No. 6 Fuel Oil. - a high-viscosity, heavy residual oil

ACTIVITY 1

P5.1 Gasoline

The liquid most widely used as fuel for internal co mbustion engines with spark ignition (SI) engine. (See the picture of modern gasoline engine)

It consists of a mixture of hydrocarbons usually c ontaining 5 to 12 carbon atoms per molecule and boiling almost entirely in the tempera ture range of about 32 oC to 205 oC.

Other equally important property of gasoline is vol atility.

Commercial gasolines are blends of petroleum refine ry products which provide the characteristics required for different engines unde r various conditions.

Overall a typical gasoline is predominantly a mixtu re of paraffins (alkanes), naphthenes (cycloalkanes), aromatics and olefins (alkenes).

The antiknock properties of gasoline fuels differ depending upon their sour ce of extraction.

Gasoline is also one of the sources of pollutant ga ses. Even if gasoline does not contain lead or sulphur compounds, it will produce carbon d ioxide, nitrogen oxides, and carbon monoxide in the exhaust of the engine which is runn ing on it. Furthermore, unburnt gasoline and evaporation from the tank, when in the atmosphere, react in sunlight to produce photochemical smog .

Gasoline evaporates easily, requiring that storage tanks be properly sealed. The high volatility also means that it will easily ignite in cold weather conditions, unlike diesel.

P5.1.1 Picture of Gasoline Engine

Example of a m odern gasoline engine

P5.1.2 Table of Antiknock Properties

Table refers to the anti knock magnitude of hydrocarbon of gasoline.

P5.1.2.1 What is “Knock”

Knock or “engine knock” is a sharp metallic noise Sometimes referred to as engine clatter or pinging, caused by the pre-ignition of fuel as it

is compressed in the cylinder, milliseconds before the normal spark plug firing. This condition typically occurs during acceleration , such as merging into highway traffic,

or under heavy load conditions, such as pulling a b oat or travel trailer. Under knock conditions, a vehicle will experience a reduction in power output as well as

reduced fuel economy.

P5.2 Kerosene

Kerosene has a heating value of around 43.1 MJ/kg, making it similar to that of diesel. It is widely used to power jet-engined aircraft, bu t is also commonly used as a heating fuel. It is a thin, clear liquid formed from hydrocarbons . Kerosene is obtained from the fractional distillation of petroleum between 150 ° C and

275 °C, resulting in a mixture of carbon chains con taining 12 to 15 carbon atoms. Its use as a cooking fuel is mostly restricted to s ome portable stoves where it is usually

less refined and contains impurities and even debri s. Kerosene is widely used as fuel for jet engines (e. g. Avtur, Jet-A, Jet-A1, Jet-B, JP-4, JP-5,

JP-7 or JP-8). One form of the fuel known as RP-1 is burned wit h liquid oxygen as rocket fuel.

The future of kerosene depends on the discovery of new applications as well as the development of new methods of production. New uses include increasing military demand for high grade kerosene to replace much of its dies el fuel with JP-8, which is a kerosene based jet fuel.

Jet A-1 refueller truck

P5.3 Diesel Fuel

Diesel fuels are either various distillates obtaine d in petroleum refining operations or blends of such distillates with residual oil.

It is produced in the fractional distillation of cr ude oil between 200°C and 350°C at atmospheric pressure.

Diesel cars, powered with compression-ignition (CI) engine generally have a better fuel economy than equivalent gasoline engines and produc e less greenhouse gas pollution. This greater fuel economy is due to the higher ener gy per-litre content of diesel fuel and also to the intrinsic efficiency of the diesel engi ne.

Diesel often contains higher quantities of sulphur. European emission standards and preferential taxation have forced oil refineries to drastically reduce the level of sulphur in diesel fuels.

Petroleum-derived diesel is composed of about 75% s aturated hydrocarbons (primarily paraffins including n, iso, and cycloparaffins), and 25% aromatic hydrocarbon s (including naphthalenes and alkylbenzenes). [6] The average chemical formula for common diesel fuel is C 12H23, ranging from approximately C 10H20 to C15H28

An important criterion of diesel fuel is the igniti on quality as indicated by the Cetane number.

The American Society for Testing and Materials (ASTM) distinguishes three main grades of diesel fuel as i) Grade 1-D, ii) Grade 2-D, iii) Grade 4-D

Activity 2 Activity 3

P5.3.1 Grade 1-D, Grade 2-D, Grade 4-D

Grade 1-D

- For applications requiring a higher volatility fuel for rapidly fluctuating loads and speeds as in light trucks and buses

- Overlaps with kerosene and jet fuel

- One major usage is to blend with no.2-D during wint er to provide improved cold flow properties

Grade 2-D

- For applications that do not require a high volatil ity fuel

- Typical applications are high speed engines that op erate for sustained periods at high load

Grade 4-D

- A heavy distillate fuel that is viscous

- May require fuel heating for proper atomization of the fuel

P5.3.2 Activity 2

1. State and discuss the important criterion of die sel fuel and its different grades.

2. How are the physical and chemical characteristic s being characterized and why are these properties important?

P5.3.3 Activity 3

1. State the constituents of a typical hydrocarbon gasoline fuel

2. How is a gasoline fuel characterized for its abi lity to ignite and combust?

3. What is the difference in terms of properties be tween gasoline and diesel fuel?

P5.4 Energy Content of Some Fuels

Energy content of some fuels

Fuel type MJ/litre MJ/kg Research octane number (RON)

Regular Gasoline 34.8

44.4 Min 91

Premium Gasoline Min 95 Autogas (LPG) (60% Propane + 40% Butane ) 26.8 Ethanol 23.5 31.1 129 Methanol 17.9 19.9 123 Gasoh ol (10% ethanol + 90% gasoline) 33.7 - 93/94 Diesel 38.60 45.41 25 Aviation gasoline (high octane gasol ine, not Jet fuel) 33.5 46.8 - Liquefied natural gas 25.3 ~55

Table 2 illustrates some of the typical fuels, liqu id or gaseous, used today in modern engines and power generating plants. The energy con tent refers to the amount of heat liberated for the burning of one unit mass of the f uel concerned. The higher the energy content the more efficient the fuel becomes.

P5.5 American Society for Testing and Material (AST M)

One of the largest voluntary standards development organizations in the world

A trusted source for technical standards for fuel t esting services

Have an important role in the information infrastru cture that guides design, manufacturing and trade in a global economy

P5.6 Activity 1

1. Identify at least 1 application for each of type of the fuel category mentioned above.

2. Discuss as to why they are selected for a specif ic application.

S.6 Coal

Coal is a non-renewable energy source because it ta kes millions of years to be created.(See the formation of coal )

It is a complex mixture of organic chemical substa nces containing carbon, hydrogen and oxygen in chemical combination, together with small er amounts of nitrogen and sulphur.(See the picture of coal )

Coal is classified into four main types i.e. i) lignite , ii) bituminous , iii) sub-bituminous and iv) anthracite . Depending on the amounts and types of carbon it c ontains, this will determine the amount of heat energy it can produce.

When coal is burned as fuel, it gives off carbon di oxide, the main greenhouse gas linked to global warming. Burning coal also produces emissions , such as sulphur, nitrogen oxide (NOx), and mercury, that can pollute the air and wa ter.

Solid coal can be converted into gas by coal gasification and into liquid by coal liquefaction

Coalification is the name given to the development of the series of substances known as peat, lignite or brown coal, sub-bituminous coal, b ituminous coal, and anthracite.

The “rank” of a coal indicates the degree of coalification .

The coal production growth in Asia is the fastest c urrently (See the detail of coal scenario) Synfuel is also derived from coal. Besides that, it also de rived from natural gas and

biomass

P6.1 The Formation of Coal ( Source )

See the explanation for the pictures

Formation of coal and how it is mined

P6.1.1 The Explanation of the Formation of Coal

The energy in coal is due to the energy stored by p lants that lived hundreds of millions of years ago, when the earth was partly covered wit h swampy forests. For millions of years, a layer of dead plants at the bottom of the swamps was covered by layers of water and dirt, trapping the energy of the dead plants. T he heat and pressure from the top layers resulted into a combustible product call coa l.

P6.2 Picture of Coal

Figure 7: A sample of coal Source

Coal is a combustible black and sometime brownish-b lack sedimentary rock composed mostly of carbon and hydrocarbons. It is the most a bundant fossil fuel produced in countries such as the US, Australia and China.

P6.3 Example of Pollution Caused by Coal

Sulphur mixes with oxygen to form sulphur dioxide ( SO2), a chemical that can affect

trees and water when it combines with moisture to p roduce acid rain.

Emissions of nitrogen oxide help create smog, and a lso contribute to acid rain.

P6.4 Coal Gasification

Breaks down coal into its components ,usually by su bjecting it to high temperature and

pressure, using steam and measured amounts of oxyge n

This leads to the production of syngas, a mixture m ainly consisting of carbon monoxide(CO) and hydrogen(H 2)

Gasification is also possibility for future energy use, as the produced syngas can be cleaned-up relatively easily leading to cleaner bur ning than burning coal directly

P6.5 Coal Liquefaction

Coal also can be converted into liquid fuels like g asoline or diesel by several different processes

Coal would be gasified to make syngas (a balanced p urified mixture of CO and H 2 gas) and the syngas condensed to make light hydrocarbons which are further processed into gasoline and diesel

P6.6 Coalification

The formation of coal from a variety of plant mater ials via biochemical and geochemical processes is called coalification. The nature of the constituents in coal is related to the degree of coalification.

Schematic of the coalification process Source

The general sequence of coalification is from lignite to sub-bituminous to bituminous and to anthracite .

P6.7 Rank of Coal

Constituents of coal

The table illustrates the typical constituents and their respective constituents in terms of

carbon, hydrogen, oxygen, nitrogen and sulphur cont ent respectively.

See the explanation of the table

P6.7.1 Explanation of the Table

Bituminous coal generally has lower concentrations of pure carbon (from 57% to 80%) and lower heat values. Bituminous coals are often s ub-divided on the basis of their heat value, being classified as low, medium, and high vo latile bituminous and sub-bituminous.

Lignite, the poorest of the true coals in terms of heat value generally contains about 35%-45% pure carbon.

All forms of coal also contain other elements prese nt in living organisms, such as sulphur and nitrogen, that are very low in absolute numbers, but that have important environmental consequences when coals are used as f uels.

A rank assigned to a particular coal, is determined largely by the fixed (or nonvolatile) carbon content and its heating value.

Typical (“proximate”) analysis is performed to det ermine the proportions of moisture, volatile matter (at a temperature of 950 oC), fixed carbon, and mineral matter (ash) in a sample of “as-received” coal.

The “ultimate” analysis gives the proportions of f ive important elements in coal, namely, carbon, hydrogen, oxygen, nitrogen, and sulphur.

An important characteristic of certain coals is th e tendency for small pieces to soften and adhere (or aggregate) upon heating – caking.

Activity 4

P6.7.1.1 Activity 4

State the differences between lower heating value ( LHV) and higher heating value (HHV) for coal. Identify types of coal that cakes and methods to reduce caking. Fill out the missing values in the following Table:

Composition and Heating Value of coals ( Source )

P6.8 The Detail of Coal Scenario

Over 4970 million tonnes of hard coal is currently produced – a 78% increase over the past 25 years. Coal production has grown fastest in Asia, while Europe has actually seen a decline in production.

Global coal production is expected to reach 7000 mi llion tonne in 2030 – with China

accounting (56% of global consumption) for around h alf the increase over this period.

Steam coal production is projected to have reached around 5200 million tonnes; coking coal 620 million tonnes; and brown coal 1200 millio n tonnes.

Coal is used to generate electricity in the United States, India, Australia, South Africa

and China. Besides electric utility companies, ind ustries and businesses with their own power plants use coal to generate electricity. Powe r plants burn coal to make steam. The steam turns turbines which generate electricity.

P6.9 Synfuel

Synfuel is derived from coal, natural gas, or bioma ss. It is also referred as fuels derived from solid mat ters such as oil shale, tar sand , plastics,

and fermentation of biomass residues. It can also refer to gaseous fuels which are produc ed in using the same technique. It is synthesized using several techniques such as Coal-To-Liquids (CTL), Gas-To-

Liquids (GTL) or Biomass to-liquid (BTL), depending on the initial feedsto ck. Synthetic crude may also be created by upgrading bitumen (a t ar like substance found in tar sands), or synthesizing liquid hydrocarbons from oi l shale and synthesis gas: a mixture of carbon monoxide and hydrogen.

(See the scenario of synfuel )

P6.9.1 Scenario of Synfuel

Among the companies that are involved in the commer cialization of synfuel worldwide are i) Sasol (South Africa), ii) Mossgas (South Africa), iii) Shell Bintulu (Malaysia) and iv) New Zealand Synfuel (New Zealand). Current world production stands at approximately 300,000 barrels per day.

Synthetic fuels require a relatively high price of crude oil in order to be competitive with petroleum-based fuels without subsidies. However, t hey offer the potential to supplement or replace petroleum-based fuels if oil prices continue to rise.

Several factors make synfuel a preferred choice in the future:

i. The base material (coal) is available in large quan tities to meet current demand ii. Coal can be use to produce gasoline, diesel or ker osene directly without the need for

additional steps such as reforming or cracking iii. It can be use with existing engines with little mod ifications iv. There is no need to construct a new network to cate r for its distribution

The crystal-clear fuel burns so cleanly in internal combustion engines that there is virtually no sulphur dioxide produced, and no aroma tics. In addition to which the formation of soot is reduced by 35 %. And toxic car bon monoxide emissions are also down by 93 %.

S.7 Natural Gas

Natural gas consists mainly of a mixture of simple paraffin hydrocarbons, of which methane (CH 4) is by far the major constituent (generally 70 to 90 volume percent). (See the table for composition of natural gas)

The gas is found entrapped in the earth's crust at varying depths beneath impervious strata, such as limestone, and may or may not be in association with oil. The gas is drawn from wells, similar to oil wells, and is usually tr ansported by pipelines, sometimes a thousand kilometres or more.

It is used primarily for heat, in industrial, comm ercial and residential settings. In many homes it is used for heating and cooking and drying of cloths. It is also used to produce electricity, in many cases using gas-fired turbines that are similar to jet engines. (See the example use of natural gas, and the scenario of natural gas )

Gas has the great advantage of producing no smoke or ash on burning, although it is usually much more expensive than coal as a fuel.

Crude natural gas, as it is obtained from a gas well, may be categorized as “dry” or “wet” gas.

Dry gas consists mainly of methane and ethane; onl y very small amounts of higher paraffin hydrocarbons.

Wet gas contains substantial amounts of the higher hydrocarbons that can be condensed to form what are called natural gas liquids.

Compressed natural gas, or CNG, is natural gas und er pressure which remains clear, odorless, and non-corrosive. Although vehicles can use natural gas as either a liquid or a gas, most vehicles use the gaseous form compressed to pressures above 200 bar.

P7.1 Table for Composition of Natural Gas

Typical Composition of Natural Gas Source

Table 5 shows the typical composition of natural ga s. Its major constituent is Methane. It varies in percentage, depending upon where natural gas is explored on the surface of the earth. The other constituents are ethane (C2H6), propane (C3H8), butanes (C4H10), carbon dioxide, oxygen, nitrogen and some higher paraffins .

traceA,He,Ne,XeRage gases

0-5%H2SHydrogen sulphide

0-5%N2Nitrogen

0-0.2%O2Oxygen

0-8%CO2Carbon Dioxide

C4H10Butane

0-20%C3H8Propane

C2H6Ethane

70-90%CH4Methane

traceA,He,Ne,XeRage gases

0-5%H2SHydrogen sulphide

0-5%N2Nitrogen

0-0.2%O2Oxygen

0-8%CO2Carbon Dioxide

C4H10Butane

0-20%C3H8Propane

C2H6Ethane

70-90%CH4Methane

P7.2 Example Use of Natural Gas

A CHP Plant ( Source )

The above figure shows a typical combined heat and power plant (CHP). This

200/240 MWe CHP plant serves a paper mill in the UK . Plant comprises two gas turbines, each with a heat recovery steam generator (HRSG) and exhaust stack, and one condensing/pass-out steam turbine. The gas and steam turbines drive 100 MVA generators. The photo shows one of the man y examples of natural gas used in CHP plant for power generation.

P7.3 Scenario of Natural Gas

Distribution of proved natural gas reserves (%) in 2004 Source

World's resources of natural gas, although finite, are enormous, while estimates of its

size continue to grow as a result of innovations i n exploration and extraction techniques. Natural gas resources are widely and p lentifully distributed around the globe. It is estimated that a significant amount o f natural gas remains to be discovered.

In 2000 total world reserves were 150.19 trillion cubic metres. Global reserves more than doubled in the last twenty years.

World's ratio of proven natural gas reserves to pr oduction at current levels is between 60 and 70 years. This represents the time that rema ining reserves would last if the present levels of production were maintained.

S.8 Nuclear Energy

Energy is released as a result of interactions invo lving atomic nuclei, that is, reactions in which there is a rearrangement of the constituents (i.e., protons and neutrons) of atomic nuclei; it is also called atomic energy.

The amount of energy releases is related to the de crease in mass by the Einstein equation for the equivalence of mass and energy; this equati on is

E = mc 2

[Where E is the energy released, m is the decrease i n mass, and c is the speed of light. If m is expres sed in kg and c in m/sec, the energy E is obtained in Joules (J)]

The nuclear reactions that are likely to prove use ful as energy source fall into two general categories: fusion and fission .

The only useful fission reactions are those in whi ch free neutrons cause fission of nuclei of certain isotopes of uranium and plutonium with odd mass numbers: uranium-233, uranium-235 and uranium-239

Only uranium-235 occurs in nature; the other two a re made artificially.

An important aspect of fission as an energy source is that it can be a self-sustaining process.

Although nuclear energy can be released in either fusion or fission reactions, the only nuclear power reactors in existence are based on fi ssion. In a nuclear reactor, the conditions are such that fission energy is released at a controlled rate. The fission energy is converted into heat in the reactor, and this is utilized to raise steam, directly or indirectly. The steam then drives a turbine-generator to produc e electricity in the conventional manner. (See the sample of diagram of nuclear power plant)

P8.1 Fusion

• the combination (or fusion) of two light nuclei lea ds to the formation of a heavier nucleus.

• A possible reaction for a future fusion reactor is the following in which deuterium and

The deuterium-tritium(DT) fusion reaction is considered the most promising for producing fusion power

The fusion re action Source

P8.2 Fission

Figure 14 : Uranium 235 fission

• a heavy nucleus is split into two nuclei of interme diate mass accompanied by a number of neutrons.

• the splitting of large nuclei such as Uranium or Pl utonium into smaller pieces with the release of considerable energy (equivalent to a mas s lose by Einstein's formula).

For example:

P8.3 Nuclear Power Plant

Example of a pressurized water nuclear reactor

Source

See the explanation of the diagram Activity 6

P8.3.1 Explanation for the Diagram of Nuclear Power Plant

The figure illustrates a typical pressurised water nuclear reactor. A nuclear plant works in much the same way that a dam or fossil-fuel plan t does, in that large turbine blades are used to operate a generator to produce electric ity. At a hydroelectric dam, the force of the falling water spins the turbine blades, whil e at a coal-fired or nuclear plant, the force of steam spins the blades. A nuclear plant, h owever, uses uranium instead of coal as a fuel to make steam.

The uranium is formed into ceramic pellets and plac ed in metal tubes called fuel rods. Fuel rods are placed in the reactor vessel to make up the core—the part of the plant that produces heat.

When a uranium atom splits in the process called nu clear fission, it gives off energy in the form of heat. To regulate the heat-producing pr ocess, control rods and borated water are used. The borated water speeds up or slows down the fission process, and the control rods shut down the reaction when they’re in serted between the fuel rods.

The water is heated to about 304 oC. It’s kept under high pressure to prevent it from boiling as it travels to tubes inside four steam ge nerators.

A secondary source of water passes around the outsi de of the tubes in the steam generators. The heat from the water inside the tube s is transferred to the secondary source of water, which boils and turns to steam. Th e steam formed in the generators is piped into the main turbine, where the force of the steam turns the turbine blades. The turbine is connected to an electric generator by a rotating shaft. As the turbine blades begin to spin, a magnet inside the generator also t urns, and that produces electricity.

Continue

P8.3.1.1 Continue of the Explanation

Once the steam has been used to drive the main turb ine, the low-energy steam is converted back to water by circulating around tubes (which carry cool water from an adjacent lake) in a large boxlike structure called a condenser. The condensed steam, now water, is pumped to the steam generators to rep eat the cycle. The water in the condenser tubes picks up heat from the steam passin g around the outside of the tubes. This heated water may be passed through a cooling t ower before being returned to the lake or reused in the plant. The three water system s are separated from each other to ensure that radioactive water does not mix with non radioactive.

In the boiling water reactor, steam is produced in the reactor core instead of in the steam generators. The turbine and generator work to make electricity just as they do in a pressurized-water nuclear plant or in a coal-fired plant.

P8.3.2 Activity 6

New, safer and more economical nuclear reactors cou ld not only satisfy many of our future energy needs but could also combat global warming a s well. Describe several of these new generation nuclear reactors and how efficient and e nvironmental-friendly can they be. How can they address challenging economic issues concer ning their capital costs and financing? Suggest some of the ways in which nuclea r waste disposal and reuse

S.9 Summary

All forms of non-renewable energy have been describ ed. They are basically hydrocarbon-based fuels, which are derivatives of l iquid crude oil, coal and gas extracted from the crust of the earth. Nonrenewable energy sources come out of the ground as liquids, gases and solids. Currently crude oil (petroleum) is the only naturally liquid commercial fuel. Natural gas inclu sive of propane and methane are normally gases, and coal is a solid. Coal, petroleu m, natural gas are classified as fossil fuels because they formed from the buried re mains of plants and animals that lived millions of years ago. Uranium ore, whi ch is solid, is mined and converted to a fuel to provide heat source for powe r plants. Uranium is not a fossil fuel. These energy sources are considered non-ren ewable because they cannot be replenished in a short period of time.

S.10 Self Assessment

1. Which of the following energy conversions produc es the least amount of pollution? a) Fossil Fuels b) Fuel Cells c) Coal d) Biomass 2. Which country or countries consumes the largest amount of energy per capita in 2007? a) Japan b) United States c) Russia d) Germany e) Continent of Africa 3. Which of the three fossil fuels below is the cle anest fuel and simplest in terms of composition? a) Natural gas b) B) Coal c) C) Oil 4. Petroleum is found a) in living things b) in planets other than earth c) in sedimentary rock formation underground d) Landfills

5. Petroleum is used a) only sparingly because it is only available in r emote areas b) very often for vehicles and power plants c) in plastic products as a key ingredient 6. Which of the following two countries consumes th e most coal in 2007? a) United States & Russia b) Germany & India c) Australia & China d) China & United States e) Los Angeles & the rest of Southern California 7. How is coal formed? a) when a proton is charged by an electron b) b) when rocks are compacted into a high-density substance c) by the culmination of plant life over million of years d) by mixing tar and water 8. Coal is used for? a) Electric power generation b) Battery-powered machines c) Solar-powered devices d) Steam generation for old locomotives 10.What are the major advantages and disadvantages of using petroleum-based fuels? 11.What do the refining processes do?

12.What is diesel fuel and why is it widely used? 13. Why do diesel engines smoke? 14. Why was the sulfur content of diesel fuel reduc ed? 15.What specification requirements of diesel fuel s hould concern users and why? 16. What advantages does natural gas have over othe r non-renewable energy sources? 17. What greenhouse gas emissions are associated wi th natural gas combustion? 18. How is liquefaction of natural gas possible? 19. What is the volume of natural gas reserves worl dwide? Is there enough to meet future needs? 20.What is a gasoline and what are its hydrocarbon constituents? 21.Is gasoline toxic or carcinogenic? Explain your argument. 22.What do Fuel Octane ratings really indicate? 23. What is the difference between 1-K and 2-K Kero sene? 24. What are the advantages, and disadvantages of u sing coal from the perspective of plant efficiency and environmental impacts? 25. What is Combined Heat & Power (CHP)?

26. What are the benefits of CHP and where can it b e used? 27. Do you of your government’s CHP target and stra tegy? Please elaborate if you do. 28.How is nuclear power initiated and how safe can it be? 29. How are nuclear wastes disposed? 30.Why can't a sustainable society be based on foss il fuels and nuclear fission? 31. What evidence suggests that within the next dec ade, the supply of conventional oil will be unable to keep up with demand"?