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International Journal of Innovative Technology and Exploring Engineering (IJITEE)ISSN: 2278!"7#$ %olu&e2$ I''ue$ ece&*er 2"2

Plants

Energy Efficiency Improvement in Thermal Power

+ene'i' ,ureh-a$ avi'on .i&-ara$ /ellington Tu&*ud0u1u$ Sa&'on ,hlanga

identification of these loses. Energy analysis evaluates th

energy generally on its quantity only, whereas exergy

analysis assesses the energy on quantity as well as the quality

The aim of the exergy analysis is to identify the magnitudes

and the locations of real energy losses, in order to improve

the existing systems, processes or components, (Tekin an

eyramogle! "##$%. This study identifies specific plant

systems and equipment where efficiency improvements can

&e reali'ed either through new installations or modifications,

and provides estimates of the resulting net plant heat rat

reductions and the orderofmagnitude costs for

implementation.

Abstract - The purpose of the study outlined in this is to identifymajor energy loss areas in Zimbabwes thermal power stations

and develop a plan to reduce them using energy and exergy

analysis as the tools. The energy supply to demand is narrowing

down day by day around the world due to the growing demand and

sometimes due to ageing of machinery. Most of the power plants

are designed by the energetic performance criteria based not only

on the first law of thermodynamics but the real useful energy loss

cannot be justified by the fist law of thermodynamics because it

does not differentiate between the !uality and !uantity of energy.

The present study deals with the comparison of energy and exergy

analysis of thermal power plants stimulated by coal. "ur national

electricity re!uirement is about #$%%M& against $'$(M& supply)

this is evident of about #$* deficit in terms of power re!uirements.

+n view of this situation the project see,s to increase output from

the ower tations /0 in the process closing down on the power

shortages now and in the future through effective and efficiency

improvement.

3i&

The main aim of the study is to identify areas where energylosses are occurring and develop them for efficient and

effective improvement in a thermal power station.

2 4*5ective'1eywords- 2nergy 2xergy 2ffective 2fficiency +mprovementThe o&)ect to satisfy this areThermal ower tation

To conduct energy analysis of the overall plant andI. I*T+-/TI* determine the efficiencies and energy losses of all th

ma)or components on the power plant.The 01-/ region including 2im&a&we they are suffering

0elect and develop the areas where energy losses arefrom critical shortage of power and this has negative impacton industrial development. The expansion on the demand

side resulted in over stretching of the current electricity

generation capacity coupled with aging thermal plants which

are still utilising old technology. The paper will focus on the

energy efficiency improvement in thermal stations.

&eing experienced.-etermine the costs and pay&ack periods for the new

technologies suggested for efficiency improvement.

! Scope

The study scope encompasses three ma)or tasks, energyThermal Power 0tations generate electricity through a

thermal power plant3 its installed capacity is designed with a

common range of &oilers feeding into common steam

receivers from where any of the tur&ines tape the steam.

/urrently only few &oilers are in operation with an output of

approximately "4"567. The power plants use coal as the

primary input for generating electricity. The plant use

89:9; of energy value of primary fuels and the remaining

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Energy Efficiency I&prove&ent in Ther&al o-er lant'

intend to increase through efficiency improvement of the

entire power plants.

utputs to the process are com&ustion products and the

power generated. Power generated for the year 89"" is a

shown in @igure " &elow.# 9urrent Supplye&and SituationTa&le 8 shows the current demand supply in 2im&a&we.

o-er generatedTa*le 2 9urrent de&and

(,/)-ependa&le /apacity "4"5671vaila&le 6aximum /apacity "4"567

6aximum -emand "9

89

:9

8"9967ur national electricity requirements are a&out 8"9967

against "4"567 supply3 this is evident of a&out 8"; deficit

in terms of power requirements as shown in ta&le 8, the future

supply demand forecast in 2im&a&we will require an

additional of "

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International Journal of Innovative Technology and Exploring Engineering (IJITEE)ISSN: 2278!"7#$ %olu&e2$ I''ue$ ece&*er 2"2

defined as the ratio of energy output to the energy input to

system (Fin et al, "##

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Energy Efficiency I&prove&ent in Ther&al o-er lant'

compared to the design characteristics.

Thermal efficiency J

The first law efficiency (the energy efficiency% of differe

components is also calculated and their comparison is

depicted in @igure B. It is noted that the energy efficiency of

the &oiler is

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International Journal of Innovative Technology and Exploring Engineering (IJITEE)ISSN: 2278!"7#$ %olu&e2$ I''ue$ ece&*er 2"2

including engineers and )ourney men left the country for

greener pastures during the era 899< and 899$ economic

meltdown.Dandalism of machinery has proven a ma)or challenge asthe security is having a tough time as one canMt tell

whether itMs an internal or external )o& which is in

operation.

DII. +E/66E*-1TI*0

The research recommends that results from this study &eused as a guide in determining future process improvement

actions. sing exergy analysis, the &oiler was found to have

the highest percentage of exergy destruction (B$.#8;% of the

overall plant ($".44;%. To reduce this loss retrofitting and

replacement of some &oiler elements is necessary for the

overall plant efficiency improvement.

"9

89

:9B9

59

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