prof. r. shanthini dec 31, 2011 1 module 02 conventional energy technologies - in electricity...

Prof. R. Shanthini Dec 31, 2011

1

Module 02

Conventional Energy Technologies

- in electricity generation from non-renewable energy sources

(coal, petroleum, natural gas and nuclear power)

- in vehicular transport

- in other primary and secondary energy consumption modes

(heating, cooling, agriculture and electronic devices)


2

How is electricity generated from

non-renewable energy sources (oil, coal or

natural gas)?

Diesel Generator

Gas Turbine (GT) Steam Turbine

(ST)

Combined Power Plant

(GT & ST)


3

http://electron9.phys.utk.edu/phys136d/modules/m8/images/gen.gif

Magnet

Rotating wire loop

Electrical output

S

N

How to rotate the wire loop?

Electric Generator

We need a rotating shaft?


4

http://www.electricityforum.com/images/motor-eout.gif

Wind turbine gives a rotating shaft


5

Water turbine could also give a rotating shaft


6

Diesel generator

It is a diesel engine coupled to a electric generator.

Diesel engine provides the rotating shaft.

http://www.rkm.com.au/animations/animation-diesel-engine.html


7

Diesel generator

It is a diesel engine coupled to a electric generator.

Diesel engine provides the rotating shaft.

http://www.rkm.com.au/animations/animation-diesel-engine.html


8

Diesel generator

http://www.myrctoys.com/engines/ottomotor_e.swf


9

Comp-ressor

fresh air

Combustion Chamber

fuel

GasTurbine

gasesto the stack

Gen

compressed air

hot gases

Gas Turbine Power Plant


10

Gas turbine to produce electricity


11

Gas turbine driving a jet engine


12



13

Comp-ressor

fresh air

Combustion Chamber

fuel

GasTurbine

gasesto the stack

Gen

compressed air

hot gases


(WGT)out

(WC)in

(QCC)in


14

Comp-ressor

fresh air

Combustion Chamber

fuel

GasTurbine

gasesto the stack

Gen

compressed air

hot gases


(WGT)out

(WC)in

(QCC)in

Useful work output = ?

Total heat input = ?

Total energy loss = ?


15


Useful work output =

Total heat input =

Thermal efficiency of the GT power plant

(WGT)out

(WC)in

(QCC)in

-

(QCC)in

(WGT)out

(WC)in

-ηthermal =

goes to electricity generation

comes with the fuel


16

= = 22 – 28%

Energy wasted:

- [ ]=

=

72 – 78% of heat released by the fuel

for 50 to 100 MW plant

(QCC)in

(WGT)out

(WC)in

-

(QCC)in

(WGT)out

(WC)in

-

ηthermal



17

= TC

1 - TH

Hot reservoir at TH K

Heat engine converts heat into work

Cold reservoir at TC K

ηthermal = Wout

Qin

Wout

Qin

Qout

< ηthermal

ηCarnot

ηCarnot


18

ηCarnot =

Carnot efficiency of the GT power plant


TC

TH

1 -Lowest temperature(exhaust gas temperature)

Highest temperature(combustion chamber temperature)

ηCarnot =

= (QCC)in

Maximum possible work output

Total heat input

Maximum possible work output ηCarnot


19


Second-law efficiency of GT power plant

(QCC)in

ηCarnot

= Maximum possible work output

Useful work output

= (QCC)

inηthermal

ηCarnot

= ηthermal

< 1


20

Steam turbine

http://www.bizaims.com/files/generator.JPG


21

SteamTurbine

Gen

Steam Turbine Power Plant


22

C

saturated water

hot gases

SteamTurbine

Gen

compressed water

superheated steam

Condenser

Pump

cooling watersaturatedsteam

Steam Generator



23

R. Shanthini 15 Aug 2010

Steam turbine to produce electricity

Oil could be used instead of coal.

Steam engines are also used to power the train.


24


C

saturated water

Gen

compressed water

superheated steam

cooling water

(WST)out

Pump

SteamTurbine

Condenser

Steam Generator

saturatedsteam

(QSG)in

hot gases

WPin


25

ηthermal = (WST)

out (WP)

in

(QSG)in

-= 30 – 40%

Energy wasted:

(QSG)in

- [ (WST)out

- (WP)in]

=

=

60 – 70% of heat released by the fuel




26

atmosphericair

fuel

GT

gasesto the stack

C

hot gases

ST

cooling water



27

atmosphericair

fuel

GT

gasesto the Stack ST

C

hot gases

ST

cooling water



28



29



30

ηthermal = Heat released by fuel

Useful work output at GT & ST

= 36 – 50%

Energy wasted:

= 50 – 64% of heat released by the fuel




31

Nuclear Power Plant

C

Pressurized water

ST

cooling water

CORE Control rods

Containment

PWR


32

R. Shanthini 15 Aug 2010

Nuclear power plant to produce electricity


33

= 31 – 34%

Energy wasted:

= 66 – 69% of heat released by the fuel


Nuclear Power Plant

ηthermal = Heat released by fuel

Useful work output at ST


34

According to the 2nd Law of Thermodynamics

when heat is converted into work, part of the heat energy must be wasted

Power generation

type

Unit size (MW)

Energy Wasted (MW)

Diesel engine 10 - 30 7 – 22

Gas Turbine 50 - 100 36 – 78

Steam Turbine 200 - 800 120 – 560

Combined (ST & GT) 300 - 600 150 – 380

Nuclear (BWR & PWR) 500 - 1100 330 – 760


35

50% - 70% lost in producing

electricity

2% - 20% lost in transmitting

electricity

Generation, transmission and end-use losses


36

Electric power sector 70% energy losses

Transportationsector

Industrialsector

Residential & Commercial

sector

80% energy losses

25% energy losses

20% energy losses

Typical energy losses in an industrialised country


37

Discussion Point:

Why oil, coal, natural gas and nuclear fuel are unsustainable?


38

Sustainable energy

is energy which is replenishable within a human lifetime and causes no long-term

damages to the environment.

Source: http://www.jsdnp.org.jm/glossary.html


39

0

500

1000

1500

2000

2500

3000

3500

4000

1965 1975 1985 1995 2005

Year

Glo

ba

l Co

nsu

mp

tion

(in

Mill

ion

to

nn

es

oil

eq

uiv

ale

nt)

Oil Hydroelectric

Coal Nuclear

Natural gas

Source: BP Statistical Review of World Energy June 2008

Nuclear Energy


40

0

200

400

600

800

1965 1975 1985 1995 2005

Year

Glo

bal C

onsu

mpt

ion

(in M

illio

n to

nnes

oil

equi

vale

nt)

Nuclear

Source: BP Statistical Review of World Energy June 2008

Nuclear Energy


41

Technological status mature

Average growth 0.7% per year

Total share of global energy mix

16% of electricity in 2007

10% of electricity in 2030 (potential)

Nuclear Energy


42

Nuclear Energy

An isotope of Uranium, 235U, is used as the reactor fuel.

A neutron striking a 235U nucleus gets absorbed into it and 236U is created.

236U is unstable and this causes the atom to fission.

The fissioning of 236U can produce over twenty different products.

Eg: 235U + 1 neutron 3 neutrons + 89Kr + 144Ba + ENERGY

Examples of fission products: 90Sr and 137Cs (half-life 30 years) 126Sn (half-life of 230,000 years, but low yield)


43Source: http://www.cameco.com/uranium_101/uranium_science/nuclear_reactors/

Nuclear Energy

Heat to Work paradigm


44

Nuclear Energy

Nuclear fission provides 16% of the world electricity production and 7% of the total energy consumption.

Current usage of uranium is about 65,000 t/yr.

The world's present measured resources of uranium in the cost category somewhat below present spot prices is about 5.5 Mt.

They could last for over 80 years at the current usage rate.

Nuclear energy is therefore not a renewable energy source.

Source: http://www.world-nuclear.org/info/inf75.html


45

Nuclear Energy

Nuclear waste and the retired nuclear plants could remain radioactive for hundreds of future generations.

Uranium is available on earth only in limited quantities. Uranium is being converted during the operation of the nuclear power plant so it won't be available any more for future generations.

Therefore nuclear power is not a sustainable source of energy.


46

Fusion Energy

The D-T Fusion Reaction

Nuclei of two isotopes of hydrogen, naturally occuring deuterium (2H) and synthetically produced tritium (3H) react to

produce a helium (He) nucleus and a neutron (n).

In each reaction, 17.6 MeV of energy (2.8 pJ) is liberated

2H + 3H 4He (3.5 MeV) + n (14.1 MeV)


47

Fusion Energy

Sun energy comes from the fusion of

hydrogen into helium.

It happens at very high temperatures

generated owing to the massive gas

cloud shrinking under its own

gravitational force.


48

Technological status research phase

Major challenge make ITER (International Thermonuclear Experimental Reactor) a success

Major barrier immense investments in research and development are needed

Total share of global energy mix

0% of electricity in 2007

Possible adverse effects

worn-out reactors will be radioactive for 50-100 years, but there is no long-lived radioactive waste

Fusion Energy


49

Combustion Engine

The combustion engine is used to power nearly all land vehicles and many water-based and air-based vehicles.

In an internal combustion engine, a fuel (gasoline for example) fills a chamber, then it is compressed to heat it up, and then is ignited by a spark plug, causing a small explosion which generates work.


50

Combustion Engine


51

EffCarnot =

TC 1 -

TH

TC

TH = Flame temperature (800oC)

= Exhaust Temperature (40oC)

EffCarnot =

313 K1 -

1073 K

71%≈

Vehicles mostly uses Internal Combustion Engines


52

A user of a car always asks for some minimum requirements while using a car.

- The drive should be smooth and easy.

- The car should maintain a good speed so as to cope up with other cars in traffic.

- Easy and fast refuelling of cars.

- A good mileage

- Less pollution


53

A Typical Car:

100 kJ

63 kJ

18 kJ

17 kJ

2 kJ

Engine losses in fuel energy conversion, In engine cooling and with exhaust gases

Energy for accessories

Standby Idle

Fuel Energy

6 kJ

12 kJ

Driveline losses

2.5 kJ

4 kJ

5.5 kJ

Aerodynamic drags

Rolling resistance

Braking

Source: http://www.fueleconomy.gov/feg/atv.shtml

Urban Driving


54

A Typical Car:

100 kJ

69 kJ

25 kJ

4 kJ

2 kJ

Engine losses in fuel energy conversion, In engine cooling and with exhaust gases

Energy for accessories

Standby Idle

Fuel Energy

5 kJ

20 kJ

Driveline losses

11 kJ

7 kJ

2 kJ

Aerodynamic drags

Rolling resistance

Braking

Source: http://www.fueleconomy.gov/feg/atv.shtml

Highway Driving


55

Electric Car:


56

Electric Car:

http://www.esb.ie/electric-cars/environment-electric-cars/how-green-are-electric-cars.jsp


57

Hybrid Car:


58

Hybrid Car:


59

Hybrid Car:

Advantages Of Hybrid Cars

• Better mileage (claimed).

• More reliable and comfortable (claimed).

• Lesser GHG emissions.

• Batteries need not be charged by an external source.

• Warranties available for batteries as well as motors.

• Less dependence on fuels.


60

Hybrid Car: Disadvantages Of Hybrid Cars

• The initial cost is higher.

• Car is heavier (110%).

• Risk of shock during an accident.

• The vehicle can be repaired only by professionals.

• Spare parts will be very costly and rare.

• Uses more rare metals (nickel metal hydride batteries and more copper wires)

• Highway driving works the IC engine and not on the battery.


61

Bio-ethanol as an alternative fuel

Bioethanol is produced from plantsthat harness the power of the sun

to convert water and CO2 to sugars (photosynthesis),

therefore it is a renewable fuel.


62

Bioethanol is produced from plantsthat harness the power of the sun

to convert water and CO2 to sugars (photosynthesis),

therefore it is a renewable fuel.

Bio-ethanol as an alternative fuel

http://wheat.pw.usda.gov/wEST/nsf/nfmain.html


63

A growing number of cars and trucks designated as FlexFuel Vehicles (FFV)

can use ethanol blended up to 85% with petrol (E85 fuel).

Today there are more than 6 million FFV's on U.S. roads alone.


64Source: http://www.distill.com/World-Fuel-Ethanol-A&O-2004.html


65

glucose molecule

Bioethanol from simple sugars:

Sugar cane and sugar beets store the energy as simple sugars, glucose (C6H12O6)

2 CH3CH2OH + 2 CO2

yeast

impure cultures of yeast produce glycerine and various organic acids

this simple-looking reaction is a bioreaction and thus very complex


66

Yeast can be replaced by the bacterium Zymomonas mobilis - gives up to 98% yields - minimal by-products - simple fermentation requirements - several-fold the production rates of yeast

Z. mobilis industrial strain CP4, originating from Brazil,vigorously fermenting glucose. Photo courtesy Katherine M. Pappas


67

sugar cane sugar cane crushed and

soluble sugar washed out

sugar cane residue

fermentation of sugars produces 5 - 12% ethanol

yeast

distilled to concentrate to 80 – 95% ethanol

used as a petrol replacement

dehydrate to 100% ethanol

used as a petrol additive

CO2

wet solids


68

Bioethanol from starch:Corn, wheat and cassava store the energy as

more complex sugars, called starch

dextrins

α-amylase

amyloglucosidase

glucose monomer

}starch(glucose polymer)


69

Liquification Liquification (at 90 – 95 deg C; (at 90 – 95 deg C;

pH = 4 - 4.5; 400 rpm)pH = 4 - 4.5; 400 rpm)

Saccharification with Saccharification with glucosidase enzymeglucosidase enzyme

(at 55 - 65 deg C, pH = 4 - 4.5)(at 55 - 65 deg C, pH = 4 - 4.5)

Cooling Cooling (32 deg C)(32 deg C)Fermentation with Fermentation with yeast yeast (40 – 50 hrs)(40 – 50 hrs)

Distillation Distillation Dehydration Dehydration

80-95% ethanol 80-95% ethanol 100% ethanol 100% ethanol

cassava flour + water + cassava flour + water + alpha-amylase enzymealpha-amylase enzyme


70

Bioethanol from Biomass (except sugars and starches):

Rice strawPaddy husksSaw dustGrasses Bagasse


71

Cellulose (40 to 60% by weight of the biomass) made from the six-carbon sugar, glucose.

Its crystalline structure makes it resistant to hydrolysis (the chemical reaction that releases simple, fermentable sugars).

Bioethanol from Biomass (except sugars and starches):


72

Currently, bioethanol yields 25% more energy output than input to produce it.

Because fossil fuel is required - for the tractor planting the corn- for the fertilizer put in the field- for the energy needed at the processing plant

Bioethanol also requires land and water.


73

Is bioethanol a sustainable energy source?


74

Bioethanol will be used in engines that convert heat into work

Engines that convert heat into work are very

inefficient


75

Biofuels, such as US corn bioethanol, Brazilian sugar cane bioethanol, Brazilian soy biodiesel and Malaysian palm-oil biodiesel, have greater total environmental impacts than fossil fuels.

Andy Tait of Greenpeace said "It is clear that what government and industry are trying to do is find a neat, drop-in solution that allows people to continue business as usual. If you are looking at the emissions from the transport sector, the first thing you need to look at is fuel efficiency and massively increasing it. That needs to come before you even get to the point of discussing which biofuels might be good or bad."


76


77

Heating


78

Cooling: air conditioning


79

Cooling: refrigeration


80

Agricultural machinery

prof. r. shanthini dec 31, 2011 1 module 02 conventional energy technologies - in electricity...

Documents

thermalgas turbine power

electricity gas turbine

steam turbine http

rotating shaftwater

diesel engine

fueluseful work output

natural gas

electricity oil