R. Shanthini 15 Aug 2010 “In the end we will conserve only what we love; we will love only what we...

R. Shanthini 15 Aug 2010

“In the end we will conserve only what we love;

we will love only what we understand; and

we will understand only what we have been taught.”

– Baba Dioum


Energy and the EnvironmentPart I

CES August 2010

Prof. R. ShanthiniDept of Chemical & Process Engineering

Faculty of EngineeringUniversity of Peradeniya


• Describe the major energy technologies

• Assess the impact of the use of energy from the environmental (ecological) point of view

• Demonstrate a comprehensive understanding of

- energy sufficiency (conservation)

- energy efficiency

- energy security and

- sustainability issues

Learning Objectives


Global primary energy consumption in 2006

≈ 15.8 TW = 15.8 x 1012 W

Global population in 2006 ≈ 6.56 billion

Global energy consumption per person in 2006

15.8 x 1012 W 6.56 x 109

≈ 2.4 kW

Source: International Energy Annual 2006 (posted Dec 19, 2008)http://www.eia.doe.gov/iea/

≈


How is electric power produced using oil, coal or natural gas?


How is electric power produced using oil, coal or natural gas?

Diesel engine

Gas Turbine (GT) Steam Turbine

(ST)

Combined Power Plant

(GT & ST)


Gas Turbine

(GT)

Steam Turbine

(ST)


(GT & ST)

Steam / Gas entry

Steam / Gas outlet

Comp-ressor

air

Combustion Chamber

fuel

GasTurbine

gasesto the stack

Gen

compressed air

hot gases

Gas Turbine Power Plant


Gas Turbine to produce Electricity


Gas Turbine driving a Jet Engine

gasesto the stack

Work

Gen

compressed air

hot gasesCombustion

Chamber

Comp-ressor

GasTurbine


air

fuel

out

Heatin

Gen

compressed air

hot gasesCombustion

Chamber

Comp-ressor

GasTurbine


gasesto the stackair

fuel

Workout

Workin

Heatin

Gen

compressed air

hot gasesCombustion

Chamber

Comp-ressor

GasTurbine


gasesto the stack

Eff = -

air

fuel

Workout

WorkinWorkout

Total

Total

Workin

Heatin

Workout

= 22 – 28%

Energy Loss

-[ - ]=

=

72 – 78% of heat released by the fuel

for 50 to 100 MW plant


Eff = -Workin

Workout

Total

Heatin

WorkinHeatin

Workout

Total

Heatin

Gen

compressed air

hot gasesCombustion

Chamber

Comp-ressor

GasTurbine


gasesto the stackair

fuel

Workout

Total

Workin

72-78% Energy Loss? Where are they lost???

Heat engine converts heat into work

Heat engine(ex: gas turbine)

Wout

Qin

Qout

Eff = Wout

Qin engine

(must happen according to the 2nd Law of Thermodynamics)

≠100%

Cold reservoir at TC K(Ex: Atmosphere)

EffCarnot =

TC 1 -

TH

Hot reservoir at TH K(Ex: Combustion chamber)

Heat engine converts heat into work

Heat engineWout

Qin

Qout

Eff = Wout

Qin engine

Effengine

EffCarnot<

(must happen)

The 2The 2ndnd Law of Thermodynamics Law of Thermodynamics

≠100%

<1

<1

SteamTurbine

Gen

Steam Turbine Power Plant

C

saturated water

hot gases

SteamTurbine

Gen

compressed water

superheated steam

Condenser

Pump

cooling watersaturatedsteam

Steam Generator(Boiler / Furnace)



Steam Turbine to produce Electricity

Oil could be used instead of coal.

Steam engines are also used to power the train.

C

saturated water

Gen

compressed water

superheated steam

cooling water

Pump

SteamTurbine

Condenser

Steam Generator


saturatedsteam

hot gases

Heat

Workout

Total

Workin

inTotal

= 30 – 40%

Energy Loss

=60 – 70% of heat released by the fuel



Eff = -Workin

Heatin

Workout

Total

Total

- - ]= Workout

TotalWorkinHeatin

Total [

C

saturated water

Gen

compressed water

superheated steam

cooling water

Pump

SteamTurbine

Condenser

Steam Generator


saturatedsteam

hot gases

Heat

Workout

Total

Workin

inTotal

Loss??? Where???

atmosphericair

fuel

GT

gasesto the stack

C

hot gases

ST

cooling water


atmosphericair

fuel

GT

gasesto the stack ST


C

hot gases

ST

cooling water

Eff = Heat released by fuel

Net Work out at GT & ST

= 36 – 50%

Energy Loss

= 50 – 64% of heat released by the fuel



Nuclear Power Plant

C

Pressurized water

ST

cooling water

CORE Control rods

Containment

PWR


Nuclear Power Plant to produce Electricity

= Heat released by nuclear fuel

Net Work out at ST

= 31 – 34%

Energy Loss

= 66 – 69% of heat released by the fuel


Nuclear Power Plant

Eff


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

R. Shanthini 15 Aug 2010 Source: www.cartoonstock.com/directory/f/fossil_fuel.asp


Where does all the lost heat from power plant go?


atmosphericair

fuel

GT

gasesto the stack ST


C

hot gases

ST

cooling water


Waste heat from power plant can be used for domestic or industrial heating purposes.

It is known as cogeneration, and efficiency can be increased up to 80% in cogeneration applications.

Discussion Point 1: What are the possibility for cogeneration applications in Sri Lanka?

Take 05 mins.


50% - 70% lost in producing

electricity

2% - 20% lost in transmitting

electricity

Generation, transmission and end-use losses


Electric power sector 70% energy losses

Transportsector

Industrialsector

Residential & Commercial

sector

80% energy losses

25% energy losses

20% energy losses

Typical energy losses in an industrialised country


Transportsector

EffCarnot =

TC 1 -

TH

TC

TH = Flame temperature

= Exhaust Temperature

EffCarnot =

600 K1 -

2000 K

70%=

mostly uses Internal Combustion Engines


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


Is there a problem in burning oil and coal to make electricity and to

drive automobiles in such an inefficient

manner?

Discussion Point 2:

Take 15 mins.


The supreme Greek God Zeus told Prometheus:

“You may give men such gifts as are suitable, but you must not give them fire for that belongs tothe Immortals.”

– Roger Lancelyn GreenTales of the Greek Heroes

Puffin Classics

End of Part I(short Break)

R. Shanthini 15 Aug 2010 “In the end we will conserve only what we love; we will love only what we...

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