ACKNOWLEDGEMENT

THERMODYNAMIC ANALYSIS OF STEAM CONDENSORWITH ON LINE TUBE CLEANING SYSTEM

Project report submitted inPartial fulfillment of the requirements forThe award of the degree of

BACHELOR OF TECHNOLOGY INMECHANICAL ENGINEERING

Submitted by ANAND MOHAN (11231A0346)

AMANULLAH SIDDIQUE (11231A0354) NIKHIL KUMAR (11231A0357)ASHISH KUMAR GUPTA (11231A0303)

Under the esteemed guidance of

K.DURGA SUSHMITHA, M.TECH ASST.PROF.

DEPARTMENT OF MECHANICAL ENGINEERINGNIMRA COLLEGE OF ENGINEERING AND TECHNOLOGY(AFFILIATED TO JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY, KAKINADA)(APPROVED BY AICTE, NEW DELHI PERMITTED BY GOVT.OF.AP)NIMRA NAGAR, JUPUDI, VIJAYAWADA, KRISHNA DIST.-521456APRIL 2015

DECLARATION

We hereby declare that the project work Report entitled THERMODYNAMICS ANALYSIS OF STEAM CONDENSOR WITH ON LINE TUBE CLEANING SYSTEM which is being submitted to the Jawaharlal Nehru Technological University Kakinada (JNTUK), in partial fulfillment of the requirements for the award of the Degree of Bachelor of Technology in the department of MECHANICAL ENGINEERING, is a bonafide report of the work carried out by us. The material contained in this project work Report has not been submitted to any University or Institution for the award of any degree.

(Register Number) (Name) (Signature)

1. 11231A0346 ANAND MOHAN2. 11231A0354 AMANULLAH SIDDIQUE3. 11231A0357 NIKHIL KUMAR4. 11231A0303 ASHISH KUMAR GUPTA

Department of MECHANICAL ENIGINEERING.

Place: NCET, VijayawadaDate:

CERTIFICATE

This is to certify that the Project entitled THERMODYNAMICS ANALYSIS OF STEAM CONDENSOR WITH ON LINE TUBE CLEANING SYSTEM submitted by ANAND MOHAN (Register number 11231A0346); AMAMNULLAH SIDDIQUE (Register number 11231A0354); NIKHIL KUMAR(Register number 11231A0357); ASHISH KUMAR GUPTA (Register number 11231A0303) is accepted as the Project submission in partial fulfillment of the requirements for the award of degree of BACHELOR OF TECHNOLOGY in the Department of MECHANICAL ENGINEERING

INTERNAL GUIDE HOD ASST.PROF.K.DURGA SUSHMITHA ASST.PROF.K.DURGA SUSHMITHA

PRINCIPAL

EXTERNAL GUIDE DR.Y.SUDHEER BABU

ACKNOWLEDGEMENT Behind every achievement there lies an unfathomable sea of gratitude to those who actuated it, without whom it could not have seen the light of the day. So we take great pleasure in expressing our heartfelt acknowledgement to all those who took part in our achievement. We also thank our beloved Head of Department Mechanical EngineeringASST. Prof. K.DURGA SUSHMITHA for his outstanding encouragement contributing to completion of this project.

We are also thankful to the principal Dr. Y.SUDHEER BABU who has given an opportunity for doing a study project at Dr. NTTPS.

It would be Endeavour to express our profound gratitude to Sri G.SRINIVASA RAO ADE Stage-2, Turbine maintenance for their motivating and exemplifying guidance that really helped in doing this project.

Lastly we exchange a word of appreciation with each other associates for stimulating discussions, cooperation in their strenuous work to present this report.

Project Associates ANAND MOHAN (11231A0346)

AMANULLAH SIDDIQUE (11231A0354) NIKHIL KUMAR (11231A0357) ASHISH KUMAR GUPTA (11231A0303)

ABSTRACTIn the operation and maintenance of a power plant, the main steam surface condenser is virtually neglected compared with other components. Efficient and reliable service from condensers requires more care in both operations and maintenance than the care that is being taken in current practice.

In the present project, those parameters, which directly or indirectly influence the performance of a condenser, have been studied. The factors include cleanliness factor, backpressure, inlet temperature and saturation temperatures, Heat transfer coefficients, LMTD, steam flow and seasonal variations. The procedure for performance test and the subsequent calculations has been studied in this book from the data collected from condenser of stage2, Dr. NTTPS.

Performance optimization of steam surface condenser is directly related to the problems that arise inevitably in any condenser like fouling, tube leakage and air leakage. These problems along with the remedial measures have been dealt with the processes of exact identification and proper monitoring in online tube cleaning system. Finally it is concluded with the optimum conditions of inlet temperature and saturation temperature, Heat transfer coefficients and LMTD for efficient condenser operation.

Dr. Narla Tatarao Thermal Power Station (Dr. NTTPS)

Dr. Narla Tatarao Thermal Power Station is one of the prestigious power plants in India, which is located on the North bank of river KRISHNA within a distance of 2KM from the river. The Plant is located in between Ibrahimpatnam and Kondapalli villages and 16KM of the north side of Vijayawada. The site lies at an elevation of about 26.5mtrs above the mean sea level. Dr. Narla Tatarao Thermal Power Station complex consists of four stages. Each stage consists of two units, which are about 210MW capacity each. The total capacity of the station is 1760MW. The first two (as stage 1) being of Russian design and manually controlled. The next four (as stage 2 & 3) are fully automated, with the boiler by Suluzer, France and Turbo-generator set by KMU, Germany. The boilers are of single pass tower type against the conventional two pass type. The turbine is of thin wall section and blades. This type of designing helped in the reduction of many subsystems used in the first stage.

FIG: POWER PLANTBall mills were used in stage 2 & 3. This facilitated the incorporation of finer fuel (coal) and input controls.Stage , II, III units are commissioned as given below:

Stage Unit NoCapacity Date commissioning

1 210MW01/11/1979

2 210MW10/10/1980

3 210MW05/10/1989

4 210MW23/08/1990

5 210MW31/03/1994

6 210MW24/02/1995

IV7500 MW06/04/2009

At Dr. NTTPS we observe the absence of cooling towers as the required water is drawn from Krishna River. The large reservoir created by Prakasam barrage on Krishna River that is maintained at minimum water level throughout the year provides an efficient direct circulation of cooling water system and meets other water requirements of the plant.

The stage1 of Dr. Narla Tatarao Thermal Power Station is linked to Singareni Collieries Company Limited (S.C.C.L) for supply of coal. Stages 2 &3 are linked to Talcher coalfields in Orissa to meet the increased demand of fuel.

The complete line diagram of steam power plant is depicted in the following figure

CONTENTSS.NO PAGE NOCHAPTER 1 INTRODUCTION 1-5 1.1 Working of Basic steam power plant11.2 Need of a condenser 21.3 Classification of steam condensers 3

CHAPTER 2 TROUBLE SHOOTING IN THE CONDENSER 6-14 2.1 Fouling in condenser 62.2 Leaky tubes 112.3 Air leakage 12

CHAPTER 3 CONDENSER ONLINE TUBE CLEANING SYSTEM 15-20 3.1Brush type cleaning system 153.2 Ball type cleaning system 16 CHAPTER 4 CONDENSER PERFORMANCE ANALYSIS 21-30 4.1Introduction to performance analysis 214.2 Input data sheet for condenser 224.3 Formulae for the performance analysis and sample calculations 24 CHAPTER 5 RESULTS AND DISCUSSIONS 31-395.1 The effects of condenser water inlet temperature 315.2 The effects of steam saturation temperature 335.3 The effects of steam flow 36

CONCLUSION 40REFERENCES 41

LIST OF FIGURESS.NO PAGE NOFIG 1.1 RANKINE CYCLE 6FIG 3.1 CONDENSER VIEW 18FIG 5.1 EFFECT OF CONDENSER INLET TEMPERATURE 31 ON HEAT TRANSFER COEFFICIENTFIG 5.2 EFFECT OF CONDENSER INLET TEMPERATURE 32 ON DEADLINE FACTORFIG 5.3 EFFECT OF CONDENSER INLET TEMPERATURE 32 ON EFFECTIVENESS FIG 5.4 EFFECT OF SATURATION TEMPERATURE 33 ON LMTD FIG 5.5 EFFECT OF SATURATION TEMPERATURE 34 ON HEAT TRANSFER COEFFICIENT FIG 5.6 EFFECT OF SATURATION TEMPERATURE 34 ON DEADLINES FACTOR FIG 5.7 EFFECT OF SATURATION TEMPERATURE 35 ON EFFECTIVENESS FIG 5.8 EFFECT OF REHEAT SPRAY 36 ON HEAT TRANSFER COEFFICIENT FIG 5.9 EFFECT OF REHEAT SPRAY 36 ON CONDENSER DULGFIG 5.10 EFFECT OF REHEAT SPRAY 37 ON CW FLOW FIG 5.11 EFFECT OF REHEAT SPRAY ON VELOCITY 38 OF WATER IN THE CONDENSER TUBES

NOMENCLATUREA condensing = Condensing surface areaBWG = British wit worth gauge c d = Condenser dutyCf = Cleanliness factorCp = specific heat of waterCW = condenser waterD = Density of waterFq = Correction for condenser heat loadFt = Correction for c.w inlet tempFw = Correction for c.w flowHcrh = Enthalpy of cold reheatHFW = Enthalpy 0f feed waterHHRH = Enthalpy of hot reheatHMS = Enthalpy of main steamHRH = Hot reheatLMTD = Log mean temp differenceMs = Main steamM.W = Meter water column NT = Number of tubesPgen = LoadR.H = Reheat sprayTout = Average c.w outlet temp Tin = Average c.w inlet tempTsat = Saturation temp corresponding to backpressureU = Uncorrected heat transfer coefficientU actual = Actual heat transfer coefficient theoretical = Theoretical heat transfer coefficientZ = constant

CHAPTER 1INTRODUCTION

1.1WORKING OF BASIC STEAM POWER PLANT

FIG 1.1 Rankine CycleSteam power plant operates on Rankine cycle. It mainly consists of boiler, turbine, condenser and pump.High pressure superheated steam leaves the boiler and enters the turbine. The steam expands in the turbine. During this process the steam does work, and this enables the turbine to drive the electric generator. The low-pressure steam leaves the turbine and enters the condenser. Heat is transferred from the steam to cooling water passing through the condenser tubes, causing the steam to condense.Since a large quantity of water is required, Power plants are generally located near rivers or lakes. When the supply of cooling water is limited, a cooling tower may be used. A pump enables condensate to flow into the boiler and increases the pressure of condensate leaving the condenser. In the boiler, the heat energy of combustion gases is used for converting water to vapour. In most of the boilers the steam is superheated and thus high pressure, high temperature steam is supplied to the turbine.1.2 THE NEED OF A CONDENSER

The maximum possible thermal efficiency of a heat engine is given by (1) T1 T2 T1

Where T1 and T2 are the supply and exhaust temperatures.

This expression of efficiency show that the efficiency increases with an increase in temperature T1 and with decrease in temperature T2. The maximum value of temperature T1 of steam supplied to steam prime mover is limited by the material consideration. The temperature T2 at which heat is rejected can be reduced if the exhaust of steam prime mover takes place below the atmospheric pressure. Low exhaust pressure means low exhaust temperature.But the steam cannot be released into the atmosphere if it is expanded in the engine or turbine below atmospheric pressure. However this can be made possible, if the steam is made to enter a vessel known as condenser, where the pressure inside is maintained below the atmospheric pressure by condensing the steam with the circulation of cold water.Thus condenser improves the efficiency of the power plant by decreasing the exhaust pressure of the steam below atmospheric pressure, as it lowers the exhaust temperature T2. Condenser provides a source of pure feed water to the boiler and thus helps in reducing the burden on the water softening plant to a great extent. So steam condenser is one of the most essential components of a thermal power plant.

CONDENSERA condenser is defined as a closed vessel in which exhaust steam from Steam turbine is condensed by cooling water, and vacuum is maintained. This results in an increase in work done and efficiency of the steam power plant and use of condensate as feed water to the boiler.The elements of a water-cooled condensing unit are:1. Closed vessel in which steam condenses.2. A dry air pump, which removes air and other non-condensable materials.3. A condensate extraction pump that extracts the condensed steam collected in the hot well of the condenser and pumps it to the feed pipe line.4. A cooling water pump to circulate the cooling water in condenser.5. A feed water pump to condensate from hot well to the boiler.

1.3 CLASSIFICATION OF STEAM CONDENSERS

The condensers are mainly classified into four types A. Mixing or jet type condenserB. Non mixing type or surface condenserC. Non conventional direct contact condenserD. Evaporative condenser

A. Mixing or jet type condenser

In mixing type condensers the exhaust steam from prime mover and cooling water come in to direct contact with each other. The condensate coming out of the mixing type condenser cannot be used as boiler feed water because it is not free from salts and pollutants. These types of condensers are generally preferred where the good quality water is easily available in ample quantity. Mixing condensers are seldom used in modern power plants. Instead parallel flow and counter flow jet condensers are used. In a parallel flow condenser, the steam and cooling water flow in the same direction. They flow in opposite directions in counter flow condenser.Mixing type condensers are mainly classified into three categories depending upon the arrangement used for the removal of condensate as low level, high level and ejector condensers. These are rarely used in modern high capacity power plants.B. Non Mixing type or surface condenserIn non-mixing type of condensers, steam and cooling water do not come in direct contact with each other. The cooling water passes through the number of tubes attached to condenser shell and steam surrounds the tubes. These types of condensers are universally used in all high capacity modern steam power plants, as the condensate coming out from the condenser used as feed for the boiler.These types of condensers are generally used where large quantity of inferior water is available and better quality of feed water to the boiler must be used most economically.The condenser that we have selected for the present study is a shell and tube type surface condenser. This condenses the exhaust steam from low pressure turbine and maintains the possible vacuum in order to increase the heat drop and the turbine output, besides making it possible to reuse the condensate thus obtained.

C. Non - Conventional direct contact condenserThis is a new concept in power industry where condensate is used to condense the exhaust steam in the condenser. In this arrangement external condensate cooler cools part of the condensate coming out of condenser and the same is used again in the condenser in the form of spray and the condenser is of mixing type.

D. Evaporative condenserThe evaporative condensers are preferred where acute shortage of cooling waterexists. In this type of condensers water is sprayed through the nozzles over pipeCarrying exhaust steam and forms a thin film over it. The air is drawn over the surfaceof the coil with the help of induced fans.The arrangement of this type of condenser is simple and cheap. It does not require large quantity of water therefore needs a small capacity cooling water pump. The vacuum maintained in this condenser is not as high as in surface condenser. Therefore the work done per kg of steam is less when compared to surface condensers.The evaporative condensers are generally preferred for small power plants and where there is acute shortage of cooling water.

Constructional features of Surface condenser

A condenser is a rectangular vessel having suitably stiffened dome, consisting of stiffening rods, welded on either side walls and of the dome shell except tubes. The remaining construction is a fabricated one. The tubes have been expanded into main tube plates and are supported by the support plates at intermittent points to prevent their sagging and to curb the flow induced vibrations. Non-condensable gases are continuously extracted in order to maintain vacuum in the condenser.Optimum utilization of steam space by providing rectangular cross-section of tube nest is an added feature of this condenser. For ensuring equitable loading of condenser tubes in the bottom rows incurring appreciable steam side pressure drop - tubes have been segregated in small bunches leaving wide lanes between them. Tube bundles have been half degree inclined towards front water box side for its self draining during cooling water pump tripping. The condenser front water chamber has provision for the isolation of half of the condenser for on load leak detection. Water boxes incorporate hinge arrangement to facilitate the removal of covers for enabling rubbing and cleaning of tubes. Water boxes and circulating water side of steel main tube plates have been protected against corrosion by the application of protective coating over the surface in contact with cooling water. Provision for sacrificial anodes has also been made for additional protection against corrosion.

InstallationCondenser has been floated over the springs, which take empty weight of condenser along with the partial operating weight while remaining operating weight is taken by the turbine foundation. Tube installation is tested by filling water into steam space up to one meter above the top tube row. Prior to filling water into condenser steam space for above testing screws provided with spring support should be used for ensuring water weight being passed on to them, to avoid over stressing of turbine foundation.

CHAPTER 2TROUBLE SHOOTINGS IN THE CONDENSER

Generally the following problems are faced in the operation of condensers in Steam power plants.

1. Fouling2. Leaky tubes3. Air leakage

2.1 FOULING IN CONDENSER

When the heat transfer apparatus has been in service for some time, dirt and scale deposits on inside and outside of the pipe. As a result the thermal resistance in the path of the heat flow increases, which reduces heat transfer rate. Thus during operation condenser tubes become fouled with an accumulation of deposits of one kind or another on heat transfer surface.

The dirt or scale formation is termed as fouling. This results in increased resistance to heat transfer is called fouling factor. This should be considered in calculating the overall heat transfer coefficient. This additional resistance reduces the original value of overall heat transfer coefficient.The economic penalty for fouling can be attributed to,1. Higher capital expenditure through over sized units.2. Energy losses due to thermal inefficiencies.3. Costs associated with periodic cleaning of heat exchanges.4. Loss of production during shut down for cleaning.

The magnitude of the fouling factor depends on nature of the scale. Th scale is uniform in composition and structure, the resistance is calculated by dividing the scale thickness by the thermal conductivity of the scale material. Usually the scale is of an unknown or complicated composition and structure and the fouling factor must be known for analyzing the performance of condenser. The fouling process is obviously a time function starting with zero and proceeding along some pseudo asymptotic or linear relationship but a constant value is generally used in design. This is then interpreted as a value to be reached in some reasonable time interval at which time the user of the equipment is willing to clean it. Allocation of exaggerated large fouling resistance also does not guarantee longer operating time. On the contrary in many cases it can contributes to more rapid deterioration.

TYPES OF FOULING PROCESSScaling or precipitation foulingOne of the common causes of fouling is due to crystallization of salts having inverse solubility character than normal solubility.Unlike normal salts certain salts exhibit decreasing solubility beyond a certain temperature. Thus when they come in contact with the heated surface crystalline deposits are formed. In water scaling, examples for such salts are CaCO3 and CaSO4.

Sedimentation or particulate foulingThe accumulation of finely divided solids like rust, dusts, clay, sand etc. on the heat transfer surface is also known as fouling. When the settling of particles due to gravity, the process of fouling is known as sedimentation. Rust and dust are Generally caused by air, where as sand and mud are carried by river water. The effects of these are partly reduced by filtering methods before the use of water for cooling.

Chemical reaction fouling or polymerizationDeposits formed at the heat transfer surface by chemical reaction in the fluid itself (in which the surface material is not a reactant) are referred to as chemical reaction fouling. This type of fouling occurs in many times in petroleum and chemical streams. Surface temperature is a critical variable, since it determines the reaction rate. A special type of chemical reaction fouling occurs in organic fluid moderated nuclear reactors.

Corrosion foulingCorrosion products of the heat transfer surface produced an additional thermal resistance. Corrosion creates roughness, which will produce nucleation sites for crystallization and particle sedimentation.

Biological foulingThe attachment of macro (clams, barnacles, mussels) and micro (algae, fungi, bacteria) organisms to heat transfer surface is known as biological fouling. This develops on heat transfer surface in contact with untreated water such as sea, river or lake water. Macro organisms pass through the intake of condenser plant and settle on the hot heat transfer surface thus impairing heat transfer.Sometimes the extent of bio fouling may be so much leading to shutdown of power station due to cooling system blockage. Cost of cleaning and lost output is extremely high. The growing interest in controlling bio fouling is due to wide use of seawater as cooling medium in power stations and OTEC plants. Bacteria are very sensitive to temperatures below 0 to 20 and above 40 to 70 degrees Celsius will kill most of the marine bacteria.

Freeze fouling or solidification foulingThe crystallization of pure liquid or one component from the liquid phase on a sub cooled heat transfer surface falls under this category.

PARAMETERS AFFECTING FOULING

Velocity

Velocity affects the fouling process with respect to both deposition and removal. The effect of velocity on removal is characterized by the strength of the deposit. For inorganic type of fouling, as the deposition rate is a controlling process the fouling rate increases with velocity .For organic type of fouling the residence time of particulates in the boundary layers decreases with increased velocity and reduces the fouling rate.The allowable velocity range is 1 to 3 m/s.

Temperature

The liquid bulk temperature, wall temperature and scale fluid interface temperature are important in the fouling process.Under constant heat flux conditions, there will be effect of temperature on deposition rate. A portion of deposit will undergo additional crystallization process as the temperature with in deposit increases.For a fluid containing inverse solubility of salts the deposition rate increases with increasing interface temperature. The fouling resistance increases asymptotically with increase in bulk temperature to a maximum, and then decreases. The decrease is due to smaller temperature gradient and therefore less mass transfer to the crystallizing surface if outlet water temperature is greater than 50 deg c corrosion problems arises.

Water chemistry

Generally PH compositions of different salt components are used to characterize the water chemistry the biological fouling mostly depends on the PH value of water used in condenser.

Tube materialsThe effect of tube material is to add corrosion products to the deposit on surface. The characteristics of tube materials also have an effect on deposition.

PREVENTION OF FOULING

Fouling can pose serious problems in process plants and some time lead to unplanned shutdowns and production losses. Fouling always leads to higher-pressure drops and hence higher operating costs. Thus fouling is an evil that must always be prevented. Unfortunately complete prevention is neither possible nor economically feasible. Therefore steps must be taken to keep fouling at minimum. This can be done by method listed below.

Proper Design of condenser

The design of a condenser plays very important role in fouling deposition.A. Velocity should kept sufficiently high (not too high as it may cause erosion and excess loss) because low velocity would not exert sufficient shear to remove fouling layer.

B. A wrong selection of material can cause corrosion and increase the fouling rate. Some experiments tried with the Teflon tubes to minimize fouling have been quite successful. They have a lower fouling initiation tendency because of smooth surface.C. Fluid with high fouling tendency should be preferably placed on tube side for greater care of cleaning. However if chemical cleaning is used, there is no preference between the tube or shell side.D. For mechanical cleaning square pitch is preferred where as for hydraulic cleaning on the shell side a large tube pitch must be used.E. As polymerization fouling is particularly sensitive to tube wall temperatures, concurrent flow is preferred in such cases that maintain lower and uniform wall temperature.F. Stagnant region in the shell side should be avoided by well proportioned baffles spacing, baffles cut and multi-segmental baffles.Treatment of process system A. Fluid system containing large amount of solid particles should be filtered before entering the condenser. B. Additive to suppress fouling or becoming increasingly popular.C. Polymer formation can be prevented by addition of stabilizers.

Cleaning system

A toproge condenser tube cleaning system uses slightly oversized abrasive sponge rubber balls, which are re-circulated through the tubes. These balls remove all fouling and even hard deposits in the tubes. This method reduces the down time lost which forms the major part of the loss due to fouling.

Biocides and BiostatsThese are used for controlling the fouling. Biocides kill the organisms where as Biostats reduce the growth of organisms. Copper and its alloys have been used as biocides but their use is too costly for use in sea thermal plant. In OTEC plants where corrosion of surfaces under the biological growth is a serious problem. Aluminum or plastic are suggested as the materials.

Sacrificial anodesUse of sacrificial anodes in the case of cast iron pipes decreases the corrosion rates and in a way prevents fouling due to corrosion.2.2 LEAKY TUBESTubes leakage is one of the major problems in condenser application. Tube may leak,1. At the tube plate joint due to the improper attachment.2. Within the length due the pealing of oxide layer.

EFFECTS DUE TO TUBE LEAKAGE 1. Condenser gets contaminated with cooling water which effects the operation of boiler and turbine. 2. Vacuum in the condenser decreases intern results in decreasing the power output. If the leaks in tubes are few in number then they just block at the both ends without shut downing the condenser. If there are more in number effect in the operation of condenser then the unit is to be shut down for replacing the leaky tubes.DETECTION OF LEAKING TUBESWhen turbine is in operationCondenser has been provided with the divided water chambers thus making it possible to locate the leaky tube and plug its ends even when turbine is in operation For locating the leaky tube concerned portion of water chamber should be isolated on cooling water side and tube plate should be dried commencing from top to bottom by the application of dry air.Tube openings should be covered with a thin polythene sheet that will get sucked in to failed tube end, alternatively tube ends should be scanned through with a lighted candle stick/smoke generator. The flame/smoke will get attracted into the leaky tube end.Leaky tube can also be detected by the use of U-tube manometer. Plug one end of tube with soft rubber and connect the other tube end with U-tube manometer having color water. Color water will get sucked into the tube in case of leaky tube; otherwise water level will remain unchanged.

When the machine is under shutdown Drain the water boxes and fill condenser steam space with water only up to one meter above top row of tubes. Water comes from the leaky tubes.2.3 AIR LEAKAGEThe sources of air leakage in the condenser are listed below,The feed water contains air in dissolved condition. The dissolved air gets liberated when the steam is formed and it is carried with the steam into the condenser.Air leaks through the joints, packing and glands into the condenser, where the pressure is below the atmospheric pressure.

The effect of air leakage in condenser are listed below,It increases the pressure in condenser or back pressure of the prime mover and reduces the work done per kg of steam.The pressure of air lowers the partial pressure of steam and its corresponding temperature. The latent heat of steam increases at low pressure .Therefore more quantity of water is required to condense one kg of steam as the quantity of latent heat removed is more. These are greater possibility of under cooling condensate with the reduction in the partial pressure of steam due to the presence of air. This phenomenon reduces the overall efficiency of the power producing plant.The heat transfer rates are greatly reduced due to the presents of air offers high resistance to heat flow. This further necessitates the more quantity of cooling water to maintain the heat transfer rates. Otherwise it reduces the rate of condensation and further increases the back pressure of the prime mover.Preventive measures should be taken to remove leaking air from the condenser to avoid bad effects. The air from the condenser is removed with the help of air pumps. The primary function of the air pump is to extract the air from the condenser.

DETERMINATION OF BREAKUP OF CONDENSER BACK PRESSURE DEVIATION

Corrosion Failures of Heat Exchanger Tubes

Corrosion is the unintended destructive interaction of a metallic component with its environment leading to its failure.Types of Corrosion Phenomena on the basis of their physical manifestation Velocity affected corrosion (erosion corrosion) Uniform corrosion Pitting corrosion Intergranular corrosion Concentration cell corrosion Galvanic corrosion Bacterial or Bio-Fouling corrosion

Factors that determine the type of corrosion process Presence of crevices in metal parts or assemblies Relative motion between the metal parts and environment Presence of dissimilar metal parts in an electrically conducting environment Temperature gradients at metal environment interface

Metals Research Laboratory (MRL) of BHEL Haridwar, who recently carried the investigations to determine the cause of these failures.

There are mainly two types of failure due to corrosion according to their report1. Dealloying Corrosion Failures2. Velocity Effected Corrosion (Erosion Corrosion) Failures

To know about these failures they had mainly done three types of tests as follows Visual Examination for both internal and external surfaces. Hardness testing. Metallographic examination.On Admiralty Brass oil cooler tubes of Dr. Narla Tatarao TPS, Srisailam HPS, Ropar TPS, Nagarjuna HPS and Admiralty Brass condenser of Ukai HPS, Cupro- Nickel condenser tubes of Kolaghat TPS.

Conclusion given by BHEL Haridwar isFailure of Heat exchanger tubes is a normal phenomenon and generally occurs either by selective leaching or velocity-effected corrosion. Preventive measures include a change in the tube material to more resistant alloys such as stainless steel or titanium but economics of this change largely dictates the feasibility of changeover. Other measures include a strict control of the water composition, periodic cleaning of the tubes to prevent deposition of muddy deposits and ensuring proper operational conditions.

However, despite the best operational practices, failures are not totally avoidable through the occurrences can be significantly reduced. However, as the above examples show, determination of the cause of failure does not require sophisticated tools and can frequently be done at the site itself, thus leading to fast corrective actions.

CHAPTER 3CONDENSER ONLINE TUBE CLEANING SYSTEM

3.1 BRUSH TYPE CLEANING SYSTEM

The Problem Corrosion and fouling of Condenser & Heat Exchanger Tubes are major factors affecting the performance of a plant. The SolutionOn Line Tube Cleaning System facilitates cleaning of the Condenser Tubes up with the Plant in operation, continuously every day without effort thus improving efficiency and wasting no downtime on shutdowns. Your equipment essentially becomes self-cleaning. The systems automatically maintain a fouling factor below the manufacturers design specification.The online tube cleaning system is actually three different variations on a similar concept, each engineered specifically for a given application. All systems require no special operator effort and no interruption in day-to-day equipment performance.

Nylon Brush TypeIn low temperature systems, each tube is fitted with a specially developed and fabricated nylon brush and special catch baskets. As the brushes travel back and forth through the tubing, they scrub the interior walls without interrupting the systems operation.

Steel Brush TypeHigh temperature process systems use stainless steel brush and steel baskets for scrubbing tubing walls.

Sponge Ball TypeSome special applications cleaning is accomplished by injecting slightly oversized sponge rubber balls which into the supply line, then recirculated in a closed loop system of their own. These re-circulating balls clean interior tubing surfaces just as efficiently as the scrubber brushes and, like the brushes, may be timed through the control panel for periodic cleaning passes.BRUSH TYPE

Brush type on-line tube cleaning systems consists of catch basket at either end of each condenser tube. A free floating brush inserted into each tube; an automatic, programmable control panel; and a four-way, flow-reversing diverter.

Propelled by liquid flow, the small brushes travel back and forth periodically through your heat exchanger or condenser tubing, scrubbing the inner walls and keeping heat flow unrestricted.

The easily installed flow diverters reverse the flow tube-side water or process fluid automatically at preset intervals. In fact, by programming the control panel to reverse the tube-side flow several times a day, the cleaning brushes are shuttled back and forth automatically and your tubing system is scrubbed to function near pack efficiency at all times.At the heart of this effortless maintenance system is the four-way diverter, controlled by a programmable control panel, which periodically shuttles the cleaning brushes to and fro within the system at certain predetermined intervals.This diverter may be timed, through the control panel, to reverse the flow of fluids at virtually any interval settings.

3.2 BALL TYPE CLEANING SYSTEM

Elastomeric rubber balls are injected into the supply line and forced through the condenser/heat exchanger tubes by the cooling water flow. Proper ball distribution is achieved by special injection method and the ball type used.Being slightly larger than the inside diameter of the tubes, balls actually wipe the tubes clean. The balls are separated from the cooling water by a strainer section, extracted by a pump, passed through a ball collector, and recirculated into the cooling water supplying closed manner.Patented vortex and turbulence promoters are installed at the strainer outlet point to enhance ball recovery. Provisions are made to turn the screens to the backwash position to clear accumulated debris. A differential pressure monitor displays the pressure drop across the strainer section. Options of continuous, intermittent, or manual cycles are provided. Optional features are also available to monitor the number of balls in circulation and indicate the quality of worn balls

Major Components and Auxiliary Equipment Of sponge ball type on line tube cleaning system are as shown in the below figure.a. Universal Debris filterb. Ball Separatorc. Ball Recirculating Skidd. Measuring and Control Systeme. Ball Monitoring Systemf. Ball charger and feederg. Ball injection Nozzles

GEA India supplies a wide range of cleaning balls to suit every application Sponge Rubber - Hardness selected to suit service conditions. High Temperature Balls - For application up to 1400 C. Abbrasive Balls - Ring/Fully coated for removal of hard deposits. Granulate Coated Balls - For use in Titanium tubes. "V"-TYPE DEBRIS SEPARATOR

The Debris Filter installed in the C.W. Inlet Line is an important secondary filtering equipment. The design and the internal construction of the Debris Filter is based on the Water flow, type, size and quantity of the Debris and the Cooling Water inlet Pressure. The Debris is collected at the inner surface of the screen, housed inside the filter. Monitoring the Differential Pressure across the Screen indicates the level of debris fouling on the filter screen. When it reaches a preset limit, the control system initiates the debris removal operation, till the screen is cleared off the debris. Debris accumulated on the inside surface of the screen is sucked by the debris extraction assembly which routes the extracted debris into the Debris Discharge Pipe connected to the main condenser outlet pipe or drain.An Electric Gear drive mounted outside the Filter housing facilitates the rotation of the Flushing Assembly. The cleaning operation ceases once the screen is clean. The salient feature of the GEA filter is that at no time is there any significant reduction of water flow during the screen cleaning operation.Many a times the extraction technique alone is inadequate to dislodge all the Debris from the screen. To effectively solve this problem the GEA Filter incorporates a special patented Rotating High Pressure Water Injecting Arm on the rear side of the screen. However, it is an optional item.

The basic principle of operations and the construction is similar to Debris Filter. It is only for our own convenience that we are calling the debris filter of size DN 200 to DN 900 as Self Cleaning Strainers. Otherwise even Debris Filters are also Self Cleaning type filters only.

FIG 3.1 CONDENSER VIEW

Design features --Easy maintainability--Flexible design to accommodate varied customer requirements.--Design standards to ASME/DIN/BS/BIS/IIS--Installation can be Horizontal/Vertical --Filter basket ranging from 900 - 3500 mm--Filter basket perforations ranging from 1 - 10 mm--Normal flushing cycle of 3 min. and adjustable as per site conditions.--Low backwash flow shall be as low as 3% of total cooling water as an additional feature--Construction in Carbon Steel, Carbon Steel Rubber lined Stainless Steel (SS 316, 316L, 317LN) and Cu Ni, to suit application.

The savings

- Keep fouling deposits from forming inside tubes.- Increase heat transfer coefficient.- Maintains constant high heat transfer rate meet design specifications.- Increases energy efficiency and heat recovery by as much as 25%.- Increase Production.- System is automatic, easy to operate and easy to maintain.- Reduces maintenance and downtime cost for your condenser/chiller or process exchanger.- Reduces the amount of chemicals needed to treat your system.- Easily installed in new or existing systems.- System pays for itself, sometimes in as little as six months

CONDENSER PERFORMANCE TESTING AND MONITORINGEfficient, reliable service from condenser requires considerably more care in both operational and maintenance that has been current practice. Generally acceptance tests and routine operational tests are conducted to have an idea about the performance of the condenser.

Condenser performance tests are carried out for two reasons

A. Acceptance tests are conducted to establish whether a condenser meets its specified performance, and whether it is capable of producing the desired condenser backpressure when operating under specified conditions. This test will also form a benchmark for future comparison.

B. Routine operational tests are conducted to monitor the condenser performance periodically, and to verify that the condenser performance is not being adversely affected by deterioration in the condenser parameters.

In both the acceptance tests and routine tests high standard of instrumentation is required, particularly in the measurement of the condenser back pressure and the cooling water temperatures. Routine tests generally use less instrumentation than acceptance tests.

CHAPTER 4CONDENSER PERFORMANCE ANALYSIS4.1 INTRODUCTIONAfter steam has surrendered its useful heat to the turbine, it passes onto the condenser. The work obtained by the turbine from the steam will increase as the backpressure is reduced, so it is always desirable to keep the backpressure at minimum achievable level. In fact, condenser backpressure is the most important operating parameter of a unit; therefore, the factors, which worsen backpressure, must be clearly identified so that effective remedial measures can be taken.There are various controllable parameters to improve/maintain the condenser performance such as cleanliness factor, air-ingress, cooling water (CW) flow etc.

In view of this it is recommended to carryout simplified routine performance test on condenser at certain frequency to identify the level of deviations and trending of performance. Objective and ScopeThe scope is limited to condenser. This test procedure shall determine the condenser performance with regard to one or more performance indices as follows.Evaluation of testIn this performance test we have taken readings of load, flow of feed water and main steam, main steam temperature (temp) and pressure(pr), Cold Reheat (CRH) steam pressure and temperature at High Pressure Turbine (HPT) exhaust, Hot Reheat (HRH) steam pressure and temperature at Intermediate Pressure Turbine (IPT) inlet, saturation temperature , HPH6 feed water inlet and outlet temperature and pressure, Economizer and HPH5 inlet feed water temperature, steam pressure at ejector nozzle, No extraction steam pressure and temperature , Input casing exhaust steam pressure and temperature and HPH6 drip temperature are taken for this test. The Condenser Duty, CW flow, Tube Velocity, LMTD, U-actual, U-theoretical, Cleanliness Factor, Expected values of LMTD and Tsat are calculated.

4.2 INPUT DATA SHEET FOR CONDENSER

1. Design cooling water temperature - 36 0c

2. Cooling water temp raise - 8.1 0c

3. Cooling water flow quantity - 30600 m3/hr

4. Condenser backpressure - 89mm of Hg abs

5. Cooling waterside pressure drop - 3.1 Mwc

6. No. of cooling water passes - 1

7. No. of tubes - 23934

8. Tube dimensions Outside diameter - 19 mm Thickness - 1 mm Ordering length - 9.9 m

9. Tube material - 90/10 copper/nickel

The following table denotes the input parameters required for the performance analysis of condenser.

LoadMW210.00209.8

Feed water flow hourly averageTPH649.00665.2

R.H. SprayTPH8.0013.5

Main steam flowTPH641.00651.5

M.S.Pressure after strainer (L/R)Kg/Cm2151.00147.5

M.S temp. before E.S V1/E.S V2 Degree. C532.00535.5

H.P.Turbine I-st blading PressureKg/cm2132.8135.00

C.R.H. Steam Pr.at H.P.T. ExhaustKg/cm237.236.75

C.R.H Steam temp.at H.P.T. Exhaust Degree. C352.5354.5

H.R.H Steam Pr.at IPT.I n let.Kg/cm23533.9

H.R.H Steam temp. at IPT.I n let Degree. C537.3538.5

L.P. Turbine Exhaust hood temp (Tsat). Degree. C45.845.7

Number of Ejectors in service Nos.22

H.p.heater 5 in let Feed water temp.Hz.168169.4

H.p.heater 6 O/L Feed water temp. Degree. C246.6257.5

H.p.heater 6 in let Feed water temp. Degree. C201.5202

H.p.heater 6 in let Feed water Pr...Kg/cm2172172

H.p.heater 6 out let Feed water Pr...Kg/cm2171171

Economizer inlet Feed water temp(L/R) Degree. C242.5239

C.W. Temp.at condenser I / L -O/L(L/R) Degree. C29.9/3932/39.55

Steam pressure at ejector nozzleKg/Cm28.28.3

No.6 Extraction steam Pr...Kg/cm23736.8

No.6 Extraction steam temp Degree. C352.3354.7

IP casing Exhaust steam temp.(L/R) Degree. C337.6337.8

H.P. Heater -6 Drip temp Degree. C228227.5

IP casing Exhaust steam Pr(L/R)Kg/cm277.1

Steam temp. at ejector nozzle Degree. C201203.00

4.3 FORMULAE FOR THE CONDENSER PERFORMANCE ANALYSIS AND SAMPLE CALCULATION

1. Determination of Condenser DutyThe amount of heat to be removed by the condenser from the steam in a given time is the Condenser Duty.

Condenser Duty = {(Heat Added MS + Heat Added HRH + Heat added spray) 860 (Pgen + Pgen losses + Heat Loss rad)} * (4.18/3600) = {(356502.103 + 58343.885 + 7797.492) 860 (209.8 + 20.98 + 2.098)}*(4.18/3600) = 258.315 KJ/S Where Condenser Duty = KJ/Sec Heat Added MS = Flow MS (HMS hFW) = 651.5 (815.164 267.9) = 356502.103 Kcal/Hr Flow MS = 651.5 Kg/Hr HMS = 815.164 Kcal/Kg HFW = 267.9 Kcal/Kg

Heat Added HRH = Flow HRH (hHRH hcrh) = 565.286 (845.554 742.342) = 58343.885 Kcal/Hr

Flow HRH = 565.286Kg/Hr HHRH = 845.554 Kcal/Kg Hcrh = 742.342 Kcal/Kg

Heat added spray = Rh spray (hHRH hFW) = 13.5 (845.554 267.962) = 7797.492 Kcal/Hr Pgen = 209.8 KW (Gross Generator Output) Heat Loss rad = 0.1% of Pgen (Radiation Losses) KW Pgen Losses = (Mech Losses + Iron Losses Stator Current Losses) Generally Pgen Losses are taken as 0.01% of Pgen.

2. Determination of Condenser Flow

The volume rate of flow of cooling water required to attain the condenser duty is given by CW flow.

Condenser DutyCW Flow = --------------------- Cp (Tout Tin) * D= 258.315 * 1000 / (4.18 * (39.55 32) * 1000) = 8.185 m3/Sec WhereCondenser Duty = 258.315 KJ/hr.Cp = 4.18 KJ/kg deg. CD = 1000 Kg/cubic meterT out = 39.55 deg. C T in = 32 deg. C

3. Water Velocity in Condenser Tube

C.W. Flow rate * 106Tube Velocity = ---------------------------------------------------------------- Tube Area * (Number of Tubes - Number Of Tubes Plugged) = 8.185* 106 / ( ( /4 * 172) * (23934 0 ) = 1.507 m/sec.WhereTube Velocity = m/secC.W. Flow Rate = m3/SecTube Area = mm2

4. Computation of Log Mean Temperature Difference (LMTD)

(Tout Tin)LMTD = ------------------------ (Tsat Tin) Ln ------------- (Tsat Tout) = (39.55 32) / Ln ((45.7 32) / (45.7 39.55)) = 9.42 deg. C

WhereLMTD = deg. CTsat = 45.7 deg. C (Saturation temperature corresponding to Back pressure)

5. Determination of Cleanliness Factor

It is the ratio of actual heat transfer coefficient to that of theoretical heat transfer coefficient, which is commonly used in diagnostics as an indicator of thermal fouling of the heat exchanger surface.

U actual (Actual heat transfer coefficient) Cf (cleanliness factor) = ---------------------------------------------------- U theoretical (Theoretical heat transfer Coefficient)

= (1685.794 / 2940.440) * 100 = 57.33 %

Condenser Flow * Cp * ( Tout Tin ) * Density of waterU actual = -----------------------------------------------------------------------A condensing * LMTD

= (8.185* 4.18 * (39.55 32) * 1000) / (14000 * 9.426 ) = 1.9574 KJ/Sec m2 0C WhereU actual = Kcal/hr m2 0CDensity of water = 1000 Kg/m3 A condensing = m2 (condensing surface area)

U theoretical = U * Tin correction factor * tube correction factor *4.882428

= (593.5 * 1.0739 * 0.945 * 4.882428) * (4.18/3600) = 3.41 KJ/sec m2 0C

Fw - INLET WATER TEMPERATURE CORRECTION FACTOR

Inlet Water 0FFwInlet Water 0FFwInlet Water 0FFw300.650600.923901.075310.659610.932911.078320.669620.941921.080330.678630.950931.083340.687640.959941.085350.696650.968951.088360.706660.975961.090370.715670.982971.092380.724680.989981.095390.733690.994991.097400.743701.0001001.100410.752711.0051011.103420.761721.0101021.105430.770731.0151031.108440.780741.0201041.110450.789751.0251051.113460.798761.0291061.115480.816781.0371081.119490.825791.0411091.121500.834801.0451101.123510.843811.0481111.125520.852821.0511121.127530.861831.0541131.129540.870841.0571141.131550.879851.0601151.133560.888861.0631161.135570.897871.0661171.137580.905881.0691181.139590.914891.0721191.141 WhereU theoretical = KJ/sec m2 0CU = heat transfer coefficient in Btu/hrs qft Tin correction factor = Correction factor for actual C.W. inlet temperature.Tube correction factor = Correction factor for tube material and Tube wall gauge.

6. Determination of expected LMTD for Deviation from Design Value

Correction for C.W. Inlet temperature (ft)

| Saturation temp test LMTD test | 1/4ft = |------------------------------------------------- | | Saturation temp design LMTD design |

= ((45.7 9.426) / (49.2 8.4)) (1/4) = 0.943. Correction for C.W. Flow (fw)

| Tube velocity test | 1/2Fw = |-------------------------- | | Tube velocity design | = (1.507 / 1.565) (1/2) = 0.981.

Correction for condenser heat load (fq):

Condenser duty design Fq = ---------------------------------Condenser duty test

= (280.68 / 258.31) = 1.087 Expected LMTDLMTD expected = LMTD test * ft * fw * fq = 9.426 * 0.943 * 0.981 * 1.087 = 9.476 deg. C

7. Determination of Expected Saturation Temperature (Taking into considerations deviation in opening value from design values)

[ Tin Tout * Expo (z ) ]Sat Temp Expected = --------------------------------- deg. C [ 1 Expo (z) ]

= (32 ( 39.55 * Expo (0.797))) / (1-Expo (0.797)= 45.74 degree C WhereTin = C.W. inlet tempTout = C.W. outlet temp

Tout - TinZ = -------------------- = (39.55 32) / 9.426 Expected LMTD = 0.797.

CHAPTER 5RESULT AND DISCUSSION

5.1 Effects of condenser inlet temperature

FIG 5.1 Effect of condenser inlet temperature on Heat transfer coefficients

Tin2627282930313233

Uthe2805.292823.422837.892852.422866.862880.892893.572901.77

Uact1234.531338.21461.51611.641798.082037.392358.462819.12

The Theoretical Heat Transfer Coefficients increasing with the increase in CW inlet temperature as shown. Because heat transfer coefficient mainly depends on LMTD, as the LMTD decreases the heat transfer coefficients gradually increases.

FIG 5.2 Effect of condenser inlet temperature on cleanliness factor

Tin2627282930313233

Cf4447.3951.556.562.770.281.5297.15

The cleanliness factor is increasing with the inlet temperature increasing, the reason for it is the increasing u-actual comparatively more than u-theoretical in the formula Cf = U-actual / U-theoretical.

FIG 5.3 Effect of condenser inlet temperature on Effectiveness

Tin2627282930313233

0.4550.4820.5130.5400.5870.6330.68640.75

The temperature difference of water outlet temperature and inlet temperature are fixed and only the water inlet temperature is increasing, so the effectiveness is increasing. = (Tout Tin)/ (Tsat Tin).

5.2 THE EFFECTS OF STEAM SATURATION TEMPERATURE

FIG 5.4 Effect of saturation temperature on LMTD

Tsat4041424344454647

LMTD6.8727.779.05210.11511.16412.20513.23914.264

Both the sides of the condenser the temperature difference is increasing so the LMTD is increasing.

FIG 5.5 Effect of saturation temperature on Heat transfer coefficients

Tsat4041424344454647

Uthe2842.132842.132842.132842.132842.132842.132842.13284.13

Uact239620651819.281628.441475.381349.511244.141154.4

With the increasing saturation temperature the actual heat transfer coefficient decreases as the LMTD is increasing. But the theoretical heat transfer coefficient remains constant as the tube velocity is not changing.

FIG 5.6 Effect of saturation temperature on Cleanliness Factor

Tsat4041424344454647

Cf84.33872.666457.29651.29147.4843.77940.617

Cleanliness factor depend on the heat transfer coefficients. With the increasing saturation temperature the actual heat transfer coefficient is decreasing remaining theoretical heat transfer coefficient constant automatically the cleanliness factor decreases. This means due the dirty tubes saturation temperature of condenser water increases.

FIG 5.7 Effect of saturation temperature on Effectiveness

Tsat4041424344454647

0.690.6390.5910.5510.5150.4850.4570.433

The temperature difference between the water inlet and outlet temperatures is fixed and the saturation temperature is increasing, so there is gradual decrease in effectiveness.

5.3 EFFECT OF STEAM FLOW

FIG 5.8 Effect of Reheat Spray on Heat transfer coefficients

Rh68101214161820

Uth2818.492825.952833.242840.372847.392854.302861.142867.93

Uac1477.651485.621493.581501.551509.541517.471525.441533.41

Whenever heated spray is increasing heat transfer is also increasing, so heat transfer coefficients are also increasing.Q = Ms (L) = Mw * Cw * (Tout Tin).

FIG 5.9 Effect of Reheat spray on Condenser Duty.

Reheat spray681012

Condenser Duty226636.46227858.04229079.62230301.211

14161820

231522.79232744.37233965.95723518.739

With the increase in steam flow the heat gained from the steam increases resulting in condenser duty increase.

FIG 5.10 Effect of Reheat sprays on CW Flow.

Rh6810121416

Cwf27979.8128130.6228281.4328432.2528583.0628733.87

1820

28884.6829035.41

The steam and water consumption for condenser is directly proportional to each other, so the water flow increases with the steam flow.

FIG 5.11 Effect of Reheat spray on the velocity of cooling water in the condenser t tubes

Rh68101214161820

V1.43061.4381.4461.45381.46151.46951.47691.484

The tube velocity increases with the steam flow, because of the increase in cooling water flow.

RESULT

The following table shows the comparison between the design values (BHEL) and calculated values. Comparison between design values and calculated values

S.NOPARAMETERSDESIGNCALCULATED VALUE

1C.W inlet temp36 0C32 0C

2C.W temp rise 8.1 0c7.55 0C

3T sat49.2 0C45.7 0C

4Load210 MW209.8 MW

5Condenser duty280.68 KJ/Sec258.315 KJ/Sec

6C.W flow8.5 m3/Sec8.185 m3/Sec

7Velocity of tube1.565 m/s1.507 m/s

8LMTD8.4 0C9.42 0C

9Cleanliness factor72.5%57.33%

10Back pressure89 mm75.473 mm

Since it is more convenient to express enormous amount of results obtained through c-programme in graphical form, the results are represented through various graphs

CONCLUSIONIn this book the need of main steam surface condenser performance analysis in a power plant is discussed.

How the various factor like condenser duty, flow of cooling water and its velocity, heat transfer coefficients, cleanliness factor, back pressure and temperatures effect the condenser performance changes have been seen. For this we have taken the readings from Dr. NTTPS, stage 2 and drawn various graphs.

In results and discussions how the cleanliness factor and back pressure of condenser vary with time duration is seen. Next the effects of inlet temperature, saturation temperature and main steam on the cleanliness factor, effectiveness, LMTD and heat transfer coefficients are discussed. From all these results the optimal conditions for the operation of a condenser are taken. We can also extend this to know how the calculated values vary from design or theoretical values.

For condenser performance main problem is fouling and corrosion when compared to other like tube leakage and air leakage. So to overcome this problem the online tube cleaning system with the help of sponge balls is suggested and the working of it is discussed.

Finally concluding with optimum values for Tin 310C, Tout 390C, Tsat 420C for getting cleanliness factor around 71%, effectiveness 64% and MTD 8 0C and heat transfer coefficients theoretical 2050 and actual 2850 Kcal/ Hr m2 0C.

REFERENCES

1. POWER PLANT ENGINEERING - P.K.NAG,

2. POWER PLANT ENGINEERING - ARORA & DOMKUNDWAR

3. PERORMANCE AND EFFICIENCY MONITORING - NTPC MANNUAL

4. BHEL MANNUAL

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