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DESIGN OF AN OIL FIRED 200MW POWER PLANT IN KADUNA

MSC PROPOSAL SEMINAR

PRESENTED BY:

LAWAL OLADIPO OLALEKAN

(MSC/ENG/10011/08-09)

SUPERVISORS: PROF.E.J BALA

DR. G.Y PAM

MECHANICAL ENGINEERING DEPARTMENT

AHMADU BELLO UNIVERSITY

ZARIA.

SEPTEMBER 2011CHAPTER ONE

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1. INTRODUCTION.

One only has to experience a power outage to be reminded of the role electricity play in every

sphere of human endeavour. Our light, heating, and cooling facilities will no longer operate. Televisions,

computers and other communication systems will become unusable. Even industries, schools and

commercial buildings will become virtually inoperable.

A power plant is an assembly of systems or subsystems to generate electricity. It may be defined

as a machine or an assembly of equipment that generates and delivers a flow of mechanical or electricalenergy. The main equipment for the generation of electric power is a generator.

Power plants are primarily determined by the type of prime mover they use. Varieties of power plant

exist and these include:

(a) Conventional power plan

Steam Engine Power PlantsSteam Turbine Power Plants

Diesel Power PlantsGas Turbine Power PlantsNuclear Power Plants Thermoelectric Generator

(b) Non conventional Power Plant

Hydro-Electric Power Plants

Therm-ionic generatorFuel-cells Power Plants

Photovoltaic solar cells Power System

(MHD) Magneto Hydrodynamic Power Plants

Fusion Reactor NPP Power S y stemBiogas, Biomass Energy Power system

Geothermal Energy Systems

Wind Energy Power SystemOcean Thermal energy conversion (OTEC)

Wave and Tidal Wave

Energy Plantation Scheme

1.1 Brief Overview of Power Generation in Nigeria.

Power generation in Nigeria can be historically traced back to 1898 when the first generatingplant was installed in the city of Lagos. From then, until 1950, the pattern of electricity development was

in the form of individual electricity power undertakings scattered all over the country .By 1950, the

integration of electricity power development led to the passage of the (ECN) Electric Corporation ofNigeria ordinance No 15 of 1950.The ordinance enabled electricity department and all other

undertakings to come under one body. The ECN and (NDA) Niger Dam Authority were merged to form

the National Electric Power Authority (NEPA) which took effect from first of April, 1972. What iscurrently called Power Holding of Nigeria was an offshoot of NEPA. The electric Power sub sector is

dominated by the Power Holding Company of Nigeria. The PHCN co-exist with Independent Power

Producers (IPP), some of which have their power purchase agreement.

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Following the introduction of electric power sector reform Act in 2005,NEPA was transformedinto a holding company which was subsequently unbundled into eighteen(18) companies including 6

power generation plants,11 distributors and 1 transmission company. The power sector reform initiated

in 1999 has introduced a new set of players (IPPs).Currently, about 29 power generation licenses have

been granted to IPPs by the National Electricity Regulatory Commission (NERC) since 2006.

Till date, Nigeria has about 6,380MW (Nigerian Energy Report, 2010) of installed electric power

generation capacity consisting of three hydropower plants and six thermal power plants. These includethe following:

Afam electric power unit

Delta electric power business unitEgbin electric power business unit

Jebba hydropower station

Kainji hydropower station

Sapele electric power business unitShiroro hydropower business unit

Mambila hydropower plant

However, a detailed overview of the Nigerian power plant history is given in table 1.

Table 1 shows a comprehensive list of power plant projects embarked upon in Nigeria till date.

FEDERAL GOVERNMENT OF NIGERIA (FGN) OWNED

S/N PLANT YEAR

COMMISSIONED

TYPE/FUEL

USED

INSTALLED

CAPACITY(MW)

NUMBER OF

TURBINES

1 Kainji 1968,1976,1978 Hydro 760 8=2X1204X80

2X100

2 Jebba 1986 Hydro 578 63 Shiroro 1990 Hydro 600 4

4 Mambila Yet to be

commissioned

Hydro 2600

5 Egbin 1985 Thermal steam

Turbine/Natural

Gas and LPFO

1320 6

6

Sapele

1978 Thermal gas

Turbine/NG

720 6

1981 Thermal gas

Turbine/NG

300 4

7 Ijora 1966/1978 Thermal gasturbine/NG

67 3

8 Delta 1966/1990 Thermal gas

turbine/NG

912 20=2X36

12X20

6X100

9 Afam 1963/1982 Thermal gas

turbine/NG

711 17

10 Orji River 1956 Coal 20 1

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TOTAL=8,588 MW

INDEPENDENT POWER PLANT PRODUCERS (IPP)

S/N PLANT YEAR

COMMISSIONED

TYPE/FUEL

USED

INSTALLED

CAPACITY(MW)

NUMBER

OF

TURBINES1 NESCO, Jos 1929 Hydro 28

2 ENRON,Lagos 2000 Thermal/NG 270 2X135

3 Trans-Amadi,Eleme

and Omuku Rivers

state

2002 Thermal Gas

Turbine/NG

90

4 Ajaokuta Steel Plant Yet to be

commissioned

Thermal Gas

Turbine/NG

1008 6X168

5 Kwale Okpai Power

Plant,Delta

2005 Thermal Gas

Turbine/NG

450

6 Siemen Power

Plant,P-Harcourt

Yet to be

commissioned

Thermal Gas

Turbine/NG

276

7 Exxon Mobil Bonny

Island Power Plant,

Rivers State

Yet to be

commissioned

Thermal Gas

Turbine/NG

388

8 ABB Group Power

Plant, Abuja

Yet to be

commissioned

Thermal

steam,gas

turbine/NG,LPFO

450

9 Eskom Power Plant,Orji,Enugu state

Yet to becommissioned

Thermal steamturbine/Coal

2,000

10 National Integrated

Power Projects(7 nos)in the Niger Delta

region

Yet to be

commissioned

Thermal gas

Turbine/NG

2,000 4x125

5x1253x125

2x125

4x125

11 Geregu,Ajaokuta,Kog

i state

2007 Thermal gas

Turbine/NG

414

12 Papalanto,Abeokuta 2007 Thermal gas

Turbine/NG

335 8x41.87

13 Alaoji power

plant,Imo

Yet to be

commissioned

Thermal gas

Turbine/NG

1078

14 NNPC/CHEVRON

Powerplant,Ijege,Lagos

Yet to be

commissioned.

Thermal gas

Turbine/NG

780

TOTAL 9567

EMERGENCY POWER PRODUCERS(EPPs)

S/N PLANT COMMISSIONED TYPE/FUEL

USED

CAPACITY(MW) NUMBER OF

TURBINES

1 Aggreko, 2001 Thermal/Diesel 15 3X5

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Katampe Abuja.

2 Aggreko,Wuse

Abuja

2001 Thermal/Diesel 20 1x20

3 Geometric,Abuja 2001 Thermal/Diesel 15 1x15

TOTAL 50

Source: MSC Thermal Power Plant Course 2010

1.2 Challenges and Prospects of The Nigerian Power Sector.

Nigeria is currently facing a serious energy crisis. Power outages are more frequent than ever and

the energy sector operates well below its capacity. The Nigerian Power Holding Company, which is incharge of the sector, is grossly inefficient. Various power projects have been embarked upon over the

years. Some of which include the following:

i. A 400MW gas turbine power plant in Afam, under the federal government shell agreement whichwas later expanded to 900MW capacity in 2001.

ii. A 480MW integrated cycle electric power plant built by ENI of Italy and operating on a two gas

turbine and one steam turbine, which was inaugurated in April 1, 2005 at Okpai, in Delta

state.iii. A 3-335MW gas fired turbine power plant built by Chinese firm (CMEC) in Okitipupa effective

from November 1, 2002.iv. A 3,960MW hydropower plant project approved by the government to be constructed on the

Mambila Plateau in Taraba state of Nigeria

In addition to the above various initiatives, several independent power plant projects have equally been

embarked upon as indicated in table 1, in order to harness the Nations oil and gas potentials and bridge

the gap of energy demand in Nigeria.

1.3 Statement of the Problem

The importance of electricity as it reflects in our day to day activities cannot be overemphasized.Nigerias demand for energy is estimated to be 7,600 (MW). However, the country only has a total

installed generating capacity of 6,000MW, which is far from being optimized as the country is only able

to achieve 3,000MW output (Nigerian Energy Report, 2009). In order to ameliorate the power crisisbeing faced in the energy sector in Nigeria and Kaduna in particular, there is need to embark on an

increased power generation drive which will also serve as part of the roadmap for the attainment of the

Nigerian Energy Vision 2020.

1.4 Present Work

A blueprint for the design and construction of a 200MW oil fired power plant is to be cited in

Kaduna river axis of Kaduna.

The power plant will be steam driven due to its economic scale. The choice of Kaduna for its location isborn out of the fact that cheap source of fuel (low pour fuel oil) can be made readily available from the

Kaduna Refining and Petrochemical Company. The fuel delivery mode will be by pipeline facilities. The

Kaduna river site has been chosen due to its vast land and hydrological resources with a capacity of

sustaining well above 900MW power plant water requirements as indicated by table 2, according to theNigerian Energy Report, 2009.

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The project will focus on the determination of the various power plant components (turbines, boilers,condensers, pumps feed water Heaters, cooling towers), optimum design pressure and temperature

parameters and the achievement of optimum overall plant efficiency.

Table 2-Estimate of current exploitable hydrological sites in Nigeria (From Nigerian Energy Report).

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1.5 Justification of Work.

Kaduna and indeed Nigeria at large have been grappling with an epileptic power supply over the

years. This has taken a toll of both domestic and industrial activities. More worrisome is the closing up

of our textile companies, major manufacturing companies such as Michelin, Dunlop and others (which in

the past accounted for over 15 percent employment generation in the country) due to the unstable power

situation.There is need to increase the power generation capacity in addition to improving the capacity

utilization of the existing ones in Nigeria. The design and citing of a 200MW oil fired power plant couldnot have come at a better time most especially when viewed against the backdrop of the energy crisis

rocking our nation. Moreover, with the PHCN available energy statistic showing 4,428MW as current

power generation capacity as against the Nigerian energy vision 2020 target of 6000MW by 2010 and10,000MW by December,2011, the 200MW power plant plan will further supplement the attainment of

this drive and help in reducing the existing energy gap.

Studies of power plant by different researchers have been an interesting feature of the Nigerian

energy sector. The concept itself is by no means a new technology. However, what may be new is itsdomestication and adaptation to suit the present day realities in Kaduna environs.

A steam driven power plant with an oil based firing method has the capacity to generate over3000MW as compared to any other conventional power plant scheme (Diesel, gas).This will, no doubt,have a far reaching effect on ameliorating the energy crisis in Kaduna ailing industries and its environs.

It requires less space when compared with a hydro power plant of the same capacity and has

lower cost of generation as compared with diesel power plants.Furthermore, steam power plants have lower installation cost, with readily available components and has

the capacity to generate higher employment opportunities.

1.6 Aim and Objectives

This work is aimed is to show that the design of a 200 MW oil fired steam power plant is feasible within

the framework of independent power plant work in Kaduna, Nigeria. The work will draw emphasis onthe following objectives:

i. To show that Kaduna has the enabling environment in terms of hydrological resourcesand right source of steady fuel supply to embark on the power plant initiative.

ii. To select the right component boiler, condenser, turbine and other accessories that make

up the project.iii. To determine the operating pressure and temperature of the boiler and condenser in order

to achieve the optimum plant efficiency.

iv. To determine the turbine work output in KJ/S

v. To determine the turbine net work output in KJ/Svi. To show the boiler heat capacity in KJ/S

vii. To determine the boiler load (steam flow rate in kg/s).

viii. To determine the fuel oil flow rate in the boiler in Kg/six. To show the condenser cooling water flow rate in kg/s.

x. To determine the type, number and process conditions of the feed water heaters required

for optimum power plant efficiency.xi. To determine the efficiency of the power plant components.

xii. To determine the overall efficiency of the plant

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xiii. And finally, to use a power plant software (thermo flow) to determine the overall plant

parameters as a confirmatory measure for all manually calculated.

1.7 Scope and Limitation Of Work

The design of a 200MW oil fired power plant within the framework of an academic research

involves some level of assumptions. However, this project will be target specific and will tend to addresskey components in its design.

Considerations shall be given to the following plant parameters which will serve as the design limits tobe observed:

1. The project shall take into account the site selection for power plant.

2. The specification and selection of boilers for setting up the power plant.3. The prime movers (steam turbines) parameters shall be duly considered with emphasis on its

specification and selection process.

4. Process condenser design and selection with due recourse to prevailing ambient conditions in

Kaduna.5. Cooling and circulation water supply and requirements (make up, treatment etc).

6. Cooling tower design, specification and selection.7. Feed water pump specification and selection8. Feed water heating design and selection.

9. Heat balances of plant cycle analysis

However, the following will not be included in the scheme of project: the details of civil-structural,

mechanical and chemical designs, ancillaries such as pipe, valves and insulation, jacketing details,

instrumentations and controls, detailed corrosion protection measures, detailed emission controls andflue gas analysis . Fuel oils selection, characteristics and analysis of air- fuel system for boiler shall not

be considered

LITERATURE REVIEW

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2.1 Power Plant Research.

It is no exaggeration that the whole mankind, indeed the entire world economy are today

governed by the forces of electricity. (Engr.M.N Manata, 1979-The development of electricity in

Nigeria, 1896-1972).

2.1 Historical Review of Power Plant.

Following the invention by Denis Papinof the steam digester in 1679, and a first piston steam

engine in 1690, early studies showed that Thomas Savery (16501715) and Thomas Newcomen (1663-

1729) designed and developed the first steam power plant. See figure 2.1. The limitation of their studieswas that the power plant was used to pump water from mines, so that coal could be brought up from a

greater depth, previously inaccessible. A lot of energy was wasted and this resulted in very low plant

efficiency. James Watt (17361819) furthered the advances in the development of the steam power plant

by designing a separate cooler (condenser) into which the steam is injected before being sent back to theboiler. The Watts engine was employed in driving locomotives, ships etc.

Newcomen's and Watt's early engines had limitations because they were powered by the vacuumgenerated by condensingsteam instead of thepressure of expanding steam.Cylindershad to be large, asthe only usable force acting on them was atmospheric pressure. Steam was only used to compensate for

the atmosphere allowing the piston to move back to its starting position.

Richard Trevith ck i(1800) introduced engines using high-pressure steam. These were much more

powerful than previous engines.

Fig 2.1 Thomas Savery and Newcomer plant.

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http://en.wikipedia.org/wiki/Denis_Papinhttp://en.wikipedia.org/wiki/Denis_Papinhttp://en.wikipedia.org/wiki/Steam_digesterhttp://en.wikipedia.org/wiki/Vacuumhttp://en.wikipedia.org/wiki/Condensationhttp://en.wikipedia.org/wiki/Condensationhttp://en.wikipedia.org/wiki/Pressurehttp://en.wikipedia.org/wiki/Cylinder_(engine)http://en.wikipedia.org/wiki/Cylinder_(engine)http://en.wikipedia.org/wiki/Cylinder_(engine)http://en.wikipedia.org/wiki/Atmospheric_pressurehttp://en.wikipedia.org/wiki/Richard_Trevithickhttp://en.wikipedia.org/wiki/Denis_Papinhttp://en.wikipedia.org/wiki/Steam_digesterhttp://en.wikipedia.org/wiki/Vacuumhttp://en.wikipedia.org/wiki/Condensationhttp://en.wikipedia.org/wiki/Pressurehttp://en.wikipedia.org/wiki/Cylinder_(engine)http://en.wikipedia.org/wiki/Atmospheric_pressurehttp://en.wikipedia.org/wiki/Richard_Trevithick


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2.2 Advances in Power Plant In Nigeria

Hitachi engineering company.(1985) under the auspices of the Nigeria Electric Power

Authority(now PHCN) designed the Egbin power plant which was commissioned in 1985 with an initial

two 220MW steam turbines, each having its own dual fuel gas/oil fired boiler. This was later upgraded to6-220MW steam turbines bringing it to a total of 1,320MW in 1987.The steam operating conditions

were 138 bar and 545C.

Chiyoda Chemical Engineering Company (1978) designed a four 14MW steam turbine generator power

plant for the Kaduna Refining and Petrochemical Company in 1978 .The power plant operates on a dualfired(fuel gas/heavy oil) 5 water tube boilers with each having a steam capacity of 120 tons/hr at 412C

and 42 bar .

Onohaebi (2010) carried out the determination of power stations for upgrading in the Nigeria powersystem.

Olayinka (2011) did a research on the implementation of preventive maintenance programme in Nigeriapower industry with emphasis on the Egbin thermal power plant.

2.2 Theoritical Background

Theoritical framework for the underlisted calculations are given by NAG, 2007)

The various cycle enthalpies are determined using the international steam table (Springer, 2008)

2.2.1 Boiler performance calculation

The heat absorbed by the boiler in generating steam is given by (Q1=ms (h4-h1) ------------21

Where,h1= enthalpy of feed water at inlet to the boiler in Kj/Kg

h4= enthalpy of steam at outlet of the boiler superheat degree in kj/kg

Ms=mass flow rate of steam in kg/s

Q1= Heat absorbed by the boiler in producing steam in kj

Turbine calculation

WT= (h4-h5) ---------------------------------------------------------------------------------------------3

Where,h5= enthalpy of steam at turbine exhaust

h4=enthalpy of steam at degree of superheat

WT= workdone by the turbine in Kj/kg

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Pump calculationWp= h6-h1---------------------------------------------------------------------------------------------------4

Where,

h6= enthalpy of feed water at pump inlet

h1=enthalpy of feed water at pump outletWp=work done on the pump.

Turbine Net workdone (WN) = (wt-wp) -------------------------------------------------------------------5

Power output of Turbine (P) = Ms (WT-WP) in KW----------------------------------------------------6

Steam Turbine mechanical efficiency (ng)

ng=MWe/MWt--------------------------------------------------------------------------------------------- 7

Where,

MWe=generator output.MWt=turbine generator input

Cycle Efficiency (nc)

nc=Wnet/Q1------------------------------------------------------------------------------------------------- 8

Condenser calculation

Heat rejected in the condenser in kj

Q2=ms (h5-h6) ---------------------------------------------------------------------------------------------- 9Where,

Q2 =Heat rejected in the condenser

Ms=mass of steam condensed in kg/s

Cooling water flow rate in Condenser

mwcpw(T2-T1)= ms(h5-h6)----------------------------------------------------------------------------- 10

Where,Mw=mass of cooling water in kg/s

cpw=specific heat capacity of cooling water

T2=Temperature of cooling water at outlet of the condenser tubes in degree CelsiusT1=Temperature of cooling water at inlet to the condenser tubes in degree Celsius

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Mass flow rate of Fuel calculation

Ws (h4-h1) =nbxWfxC.V -------------------------------------------------------------------------- 11

Where nb=boiler efficiency

Wf= mass flow rate of fuel in kg/sC.V =Calorific value of fuel in KJ/Kg

Feed Water Heater calculations

This is based on heat balance approach and the number of feedwater heater in a power plant determinesthe nature of the heat balance analysis.

Pump capacity determination.

Note that this is obtained from UFC ASME Power plant design, 2002

Capacity=1.25x boiler steaming capacity in m3/s ------------------------------------------------- 12

2.3 Review Of Steam Power Plant Components.

The steam power plant is an integration of various components. A typical steam plant is illustrated in fig

2.2. The steam power plant is based on Rankine cycle,a power plant that uses steam as workingsubstance. Steam is generated in a boiler, expanded in the prime mover (steam turbine) and condensed in

the condenser and fed into the boiler again.

Studies have shown (principles of power system, V.K Mehta 2002) that a steam power plant must meetthe following requirements:

1. Furnace to burn the fuel.

2. Steam generator or boiler containing water. Heat generated in the furnace is utilized to convert waterin steam.

3. Main power unit such as an engine or turbine to use the heat energy of steam and perform work.

4. Piping system to convey steam and water.

In addition to the above equipment the plant requires various auxiliaries and accessories depending upon

the availability of water, fuel and the service for which the plant is intended.

The flow sheet of a thermal power plant consists of the following four main circuits:(i) Feed water and steam flow circuit

(ii) Fuel and fuel handling with waste disposal circuit

(iii) Air and gas circuit(iv) Cooling water circuit.

The different types of systems and components used in steam power plant are as follows:

(i) High pressure boiler(ii) Steam turbines

(iii) Condensers and cooling towers

(iv) Fuel handling system. E.g. fuel oil, coal, fuel gas

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(v) Flue gas, ash and dust handling system

(vi) Feed water purification plant(vii) Pumping system

(viii) Feed water heaters.

Fig 2.2 A Rankine cycle with a two stage steam turbine and a single feed water heater

STEAM GENERATORS: A steam generator is a device that generates steam at the desired rate,

pressure and temperature.Steam generators or boilers come under various classifications (power plantEngineering,P.K Nag 2001). From the viewpoint of applications, they can be (i) utility steam generators

(ii) Industrial steam generators (iii) marine steam generators.Utility steam generators are those used by utilities for electric power generating plants. They can beeither subcritical (steam pressure below 221.2 bar) or supercritical (above 221.2 bar).Subcritical steam

generators are water tube drum type and their operating is between 130 to 180 bar steam pressure. The

supercritical steam generators are drumless once-through type and operate at 240 bar pressure or higher.

They can either be natural circulation of forced circulation typeThey can also be classified according to the relative flow of products of combustion or flue gases or

water. They are either water tube or fire tube type

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FEED WATER HEATERS are used to raise the temperature of the water or to increase the meantemperature of heat addition in the cycle before it enters the boiler. They are either open or closed type.

STEAM TURBINE. The steam turbine generator is the primary power conversion component of the

power plant. It is a prime mover which continuously converts the energy of high pressure, high

temperature steam supplied by a steam generator into a shaft work with the low temperature steam

exhausted to a condenser. The function of the steam turbine generator is to convert the thermal energy ofthe steam from the steam generator to electrical energy.

Steam turbines are classified as either impulse, reaction or a combination stage. They can also beclassified by pressure reheat condition, exhaust pressure (back pressure or condensing), shaft orientation,

designations or extraction conditions

CONDENSER.A condenser is a closed vessel in which steam is condensed by abstracting the heat and

where the pressure is maintained below atmospheric pressure. Therefore, the function of the condenser

are: (1) to condense the steam leaving the turbine, collect the condensate, and lower the turbine exhaust

pressure.(2) to produce a vacuum or desired back pressure at the turbine exhaust for the improvement ofplant heat rate, (3) to condense turbine exhaust steam for reuse in the closed cycle, (4) to deaerate the

condensate, and (5) to accept heater drains, makeup water, steam drains, and start-up and emergencydrains. The condensing of the steam requires the condenser to remove the heat of vaporization from thesteam and reject it. Condensers are designed to reject this energy directly into cooling water or directly

into the atmosphere. Condensers are divided into water cooled or air cooled types. The water cooled

condensers are further divided into two types: (a) direct contact type condenser. (b) Surface condensers,which are shell and tube heat exchangers side them.

PUMP .A pump is a machine that imparts energy into a liquid to lift the liquid to a higher level, totransport the liquid from one Place to another, to pressurize the liquid for some useful purpose, or to

circulate the liquid in a piping system by overcoming the frictional resistance of the piping system

(Lawrence J. Seibolt, 1996)

The basic steam power plant cycle pump includes a combination of a condensing and a feedwater heatingcycle, and this requires a minimum of three pumps:

1. A condensate pump that transfers the condensate from the condenser hot well into the deaerator

2. A boiler feed pump that transfers feedwater from the feedwater heaters to the economizer or the boilersteam drum

3. A circulating water pump that provides cooling water through the condenser to condense the exhaust

steam from the turbine. Pumps that are found in power plants come in a variety of sizes and designs thatdepend on the fluid and the service. From the Hydraulic Institute Standard, Figure 2.37 illustrates of

types of pump. However, pumps are divided into two major categories: dynamic/centrifugal and

displacement pumps (Herbert.B.Lammers, 1998)

1. Dynamic (kinetic) pumps are those in which energy is continuously added to increase fluid velocities.

These pumps include centrifugal and regenerative pumps.

2. Displacement pumps are those in which energy is added periodically by the application of force. Thesepumps include reciprocating and rotary-type pumps.

Pumps also can be identified in four general classifications as follows:

1. Reciprocating pumps. 2. Rotary pumps- gear, screw, and vane pumps.3. Centrifugal pumps-radial-flow, mixed-flow, and axial-flow pumps, and the designs can be single or

multiple stage.

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CHAPTER 3

METHODOLOGY

3.1 INTRODUCTION

Chapter three of this project focuses on the design parameters, process and equipment selectionas well as economic considerations for the design of a 200MW oil fired power plant.

Considerations will be given to suitable choice of power plant site selection and source of fuel and water

requirements. The process design and selection of steam turbine, boiler, condenser and boiler feed water

pumps and heaters shall be discussed.Power plant software (steam/thermo flow) which shall take into account the various process parameters

will be used to simulate the process equipment. The steam turbine design and selection will form thebasis of the power plant design.In order to design a 200MW power plant, four-100MW turbine generators units will be considered. Each

unit will operate on a stand alone cycle arrangement with a 100MW capacity. The additional capacity of

200mw (two-100mw team turbine) is based on the need to make provision for two standby spares in theevent of failure of one of the process line and one power plant for future expansion consideration.

The cogeneration power plant which involves a controlled condensing/extraction cycle option will be

adopted in the power plant scheme. This will, in addition to being able to generate a combined capacityof 200mw, will also supply extracted steam for feed water heating .Though the cycle is relatively more

expensive than other forms like straight condensing type in terms of installation cost, the lower

operational and maintenance cost coupled with higher plant output will justify such a choice from an

economic point of view.

3.2 Steam turbine design

The steam turbine design and selection process shall consider the following items:

Turbine Generators. Turbine generators shall be designed and selected in accordance with

outlined procedures. The turbine shall be of the controlled extracting/condensing type,tandemcoumpound double flow exhaust arrangement. The following are the major process parameters which

will be determined for a condensing turbine in a regenerative cycle using superheated inlet steam.

1) HP turbine throttle temperature.2) HP turbine throttle pressure.

3) HP turbine exhaust pressure.

4) HP turbine first stage pressure.5) IP Turbine throttle temperature.

6) IP Turbine throttle pressure.

7) LP Turbine throttle temperature.8) LP Turbine throttle pressure.

9) LP Turbine exhaust pressure.

10) Generator output.

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.

12) Boiler feed pump discharge temperature.13) Boiler feed pump discharge pressure.

14) Highest pressure feedwater heater feedwater inlet temperature.

15) Highest pressure feedwater heater feedwater outlet temperature.

16) Highest pressure feedwater heater drains outlet temperature.17) Highest pressure feedwater heater extraction temperature.

18) Highest pressure feedwater heater extraction pressure.19) Feedwater flow to boiler.

20) Feedwater pressure at boiler inlet.

b) As a result of calculations based on above methods, the following design parameters can be

quantified.

1) Maximum capability of steam turbine.

2) Heat rate.3) Enthalpy-drop efficiency.

4) Type of turbine

3.3 Steam Generators. The water tube, field erect type of Steam generator shall be adopted for the power

plant because of its enhanced capacity to produce steam load as well as operating pressure higher than

that of fire tube type since we are looking at 100mw power plant. The method below shall be employed.

Input/Output Method

a) The following are the major parameters which must be made for input/output method.1) Fuel oil flow.

2) Higher heating value.

3) Combustion air temperature.

4) Feedwater flow.5) Feedwater temperature.

6) Feedwater pressure.

7) Main steam temperature.8) Main steam pressure.

9) Drum pressure

b) As a result of the calculations based on above methods, the following design parameters can be

quantified.

1) Steam generator efficiency.

2) Steam generator flow.3) Steam temperature and control range.

4) Boiler capacity.

3.4 Condensers. Condensers shall be designed in accordance with the prevailing mean ambient

temperature in Kaduna. This will be used to determine the cooling water inlet temperature for the

condenser. The Heat Exchanger Institute shall also be consulted in order to determine appropriate backpressure corresponding to the turbine.

a) The following are the major parameters for consideration.

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1) Circulating water flow.

2) Condenser pressure.3) Condenser inlet cooling water pressure.

4) Condenser inlet cooling water temperature.

5) Condenser outlet cooling water pressure.

6) Condenser outlet cooling water temperature.

7) Condenser absolute pressure.b) As a result of calculations based on above method, the following parameters can be quantified.

1) Condenser tube cleanliness factor.2) Condenser heat load.

3) Condenser type

3.5 Feedwater heater; Feedwater heaters and auxiliary cooling water heat exchangers shall be designed

based on the following parameters:

Closed Feedwater Heaters.

1) Feedwater flow.2) Feedwater inlet temperature.

3) Feedwater outlet temperature.4) Feedwater inlet pressure.5) Feedwater outlet pressure.

6) Drain inlet flow (where applicable).

7) Drain inlet pressure (where applicable).8) Drain inlet temperature (where applicable).

9) Drain outlet flow.

10) Drain outlet temperature.11) Drain outlet pressure.

12) Extraction steam flow.

13) Extraction steam temperature.

14) Extraction steam pressure.15) Heater pressure.

In addition to these parameters, the heater manufacturer's design data will be considered.

b) As a result of calculations based on above methods, the following parameters can be determined.1) Terminal temperature difference.

2) Feedwater temperature rise.

3) Drain cooler approach (where applicable).

3.6 Pumps. Centrifugal pumps shall be the favoured choice for process pumps because of its large

volume capacity (condensate, circulating and boiler water feed pump) and it shall be designed inaccordance with the prescribed steps.

a) The following are the major parameters which must considered for each pump.

1) Inlet flow.2) Inlet temperature.

3) Inlet pressure.

4) Discharge flow.

b) As a result of calculations based on above methods, the following pump parameters should be able to

be determined for pump selection.

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1) Capacity.

2) Pump total head.3) Pump work input.

4) Pump efficiency.

REFERENCES:

A Comprehensive Approach to the Analysis of Cooling Tower Performance, Trans. ASME,

1961.

A.K Raja.2006. Power Plant Engineering

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Black and Veatch, 1996.Power Plant Engineering

Cooling Tower Performance Curves, Blue Book, Cooling Technology Institute, Houston,Tex.,

1970.

CHAUDHRY, M. H. 1979.Applied Hydraulic Transients

Evaluated Weather Data for Cooling Equipment Design, Fluor Products Co. Cooling Towers,

Power, Mar. 1963. Baker and Shryock,

HENSLEY, JOHN C, EDITOR. 1985. Cooling Tower Fundamentals

J.Edward Pope, 2007.Rule of Thumb for Mechanical Engineer.

Kern,D.Q.: Process Heat Transfer, McGraw-Hill, New York, 1950.

Li, KAM W. and A. PAUL PRIDDY. 1985.Power Plant System Design.

John Wiley & Sons. New York, NY.

Nigerias Dual Problems: Policy Issues and Challenges. International Association for Energy

Economics, Akin Iwayemi.

National Energy Databank, www.energydatabank.org

Power Plant Engineering, Black and Veatch-2001.

Power Sector Reforms in Nigeria; O.I Okoro, I.P Govenderand E. Chikumi

Robert C. Rosaler (ed.), HVAC Systems and Components Handbook, 2d ed., McGraw-Hill, NewYork, 1998;

Sherwood,T. K., and R. L. Pigford: Absorption and Extraction, 2d ed., McGraw-Hill, New York,1952, pp. 102104.

V.K Methta (2002) Principle of Power System.

Wikipedia, the free encyclopedia.www.wikipedia.com

Hon. Minister of Power & Steel and Chairman of the NEPA Technical Committee(2004). ThePower Sector The Catalyst for Economic Growth and Development At anInteractive Forum withMr. President

Nagrath I. J.; Kethari D. P. [1994] Power System Engineering First Edition, TenthReprint, 2001by Tata McGraw Hill

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http://www.energydatabank.org/http://www.energydatabank.org/


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Olle I. E. [1993] Electric Energy Systems Theory TMH Edition (1977 Reprint) TataMcGraw-HillPublishing Company Ltd, New Delhi

Power Thermoflow software ,World Co-operation (2000-2010) Power plantSimulator, Version 8.0 licensed only for Evaluation

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Edited 2011 Sept

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Transcript of Edited 2011 Sept