Chapter

INTRODUCTION

Mymensingh Power Station

Rural Power Company Limited (RPCL)

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1.1 Rural Power Company Limited (RPCL):

Bangladesh is presently facing shortage of power and there are always load shading in some parts

of the country. This is threatening to the agriculture, industry, commerce as well as the whole

economy. Rural Power Company Limited is committed to reliable power generation for Rural

Development and also to take part in social & economic development for rural people of the

country.

Rural Power Company Limited (RPCL) is the first Independent Power Producer (IPP) of

Bangladesh and the first non- BPDB (Bangladesh Power Development Board) entity to be licensed

to take up power generation. Rural Power Company Limited is registered as a public limited

company under company ACT 1913, was incorporated on 31st December, 1994 under the

company laws to build, own and operate power generation projects with business philosophy and

principles. The company was established as a Pilot Project of Private Power Generation as per

ECNEC decision on 23rd November, 1994 to enhance the privatization in the Power sector of

Bangladesh.

RPCL has opened a new dimension of power generation in private sector of Bangladesh, because

the 100% equity investment is mobilized locally. This is absolutely a National Company in the

private sector.

Currently RPCL is running the following projects:

Mymensingh Power Station (MPS); Capacity: 210 MW

Gazipur Dual Fuel Power Plant; Capacity 52 MW

RPCL Powergen. Limited at Kadda, Gazipur ; Capacity 150 MW

Raozan Dual Fuel Power Plant; Capacity 25 MW

1.2 Mymensingh Power Station at a glance:

MPS is one of the leading power plants of the country, securing the first position for the last three

consecutive years. This is a 210 MW combined cycle power plant that has been developed to

todays stage through three phases. At Phase-I, it was a barge plant of 70 MW capacity (2x35 MW

Gas turbine) commissioned in 1999. Constructed near Narayanganj, it was sailed to its present

location on the river Brahmaputtra and was a floating giant. Hence the first phase infrastructure

consists the facilities of maintaining the plant on water and keeping it floating. But in todays

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context the river water has significantly reduced and as a result the barge plant is now hard to be

differentiated from a land one. In the year 2000, the Phase - II was commissioned with capacity of

another 70 MW (2x35 MW Gas turbine). And to utilize the waste gas rather than to leave it to the

atmosphere, a 70 MW steam turbine was commissioned in the year 2007.

Table.1 Phases of MPS

Phase Commissioning year Type Capacity

Phase I 1999 Gas Turbine 35 x 2 = 70 MW

Phase II 2000 Gas Turbine 35 x 2 = 70 MW

Phase III 2007 Steam Turbine 70 MW

1.2.1 Features of Plant Machinery Phase I & II:

Gas Turbine Type PG6551B & PG6561B (GE, France)

Generators Type T600C (ALSTOM, France)

Unit Step-Up Transformer 35/50 MVA (Hundai, Korea)

Substation & Switchgear ABB, Sweden

1.2.2 Special Features:

Modern & Environment friendly technology.

Enclosed by acoustic walls to reduce noise.

Dry low NOx combustion system to reduce NOx.

Mark-V & Distributed Control System (DCS).

Plant design includes multiple layers of backup control levels to ensure high availability.

Plant Control is state of art with computerized generation control and a complete

monitoring system of all significant data.

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1.2.3 Features of Plant Machinery Phase III:

Steam Turbine Model NK 90/3.2 (Siemens, Germany)

Generator Model TLRI 100/36 (Siemens, Germany)

Unit Step-Up Transformer 70/100 MVA (Siemens, Germany)

Boiler (HRSG) Standard Fasel, Netherland.

Air Cooled Condenser (ACC) Air flow capacity 82.5 Kg/s (Germany)

Water Treatment Unit (WTU) Capacity 11.5 m3/hr (Netherland)

1.2.4 Special Features:

Modern and Environment friendly technology.

Continuous Exhaust Monitoring System (CEMS).

PCS-7 Control System.

MIS (Maintenance Information System) Server.

CMMS (Computerized Maintenance Management System).

THOMS ( Thomassen Online Monitoring System) remote monitoring.

1.3 Plant Overview

MPS has installed capacity 210MW with four GT cycle (4X35MW) and one Steam Turbine of

75MW capacity. There are three phases in total. Phase I consists of 2X35MW Gas Turbine which

was commissioned in November 1999. Phase II consists of 2X35MW Gas Turbine which was

commissioned in November 2000 and Phase III consists of 1X70MW Steam Turbine which was

commissioned in 2007.

The total cost for 3 phases is BDT 15078738882.00

At the top of the Organogram a Plant Manager takes the overall responsibilities of the Power Plant.

He is the Head of HR, Administration Division and SSI Division. In Mymensingh Power Station

(MPS) there is a Deputy Plant Manager who works under the Plant Manager. There are five

Divisions under the Deputy Plant Manager. These are Operation, Mechanical Maintenance,

Electrical, I & C Maintenance and Project Divisions. One Manager works under the Mechanical

Maintenance Division who has huge responsibilities in the Power Plant which was shown in below.

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Organogram

Deputy Manager (1)

- Phase I & II

Deputy Manager (1)

Phase III

Assist. Manager (1)

Plant Engineer (2)

Senior Plant Tech. (1)

Plant technician (2) and

Assistant Technician (4)

Assist. Manager (3)

Plant Engineer (4)

Senior Plant Tech. (3)

Plant technician (4) and

Assistant Technician (4)

Plant Manager

Deputy Plant Manager

Operation

Division

Mechanical

Maintenance

Division

Electrical

Maintenance

Division

I & C

Maintenance

Division

Project

Division

Manager (1) Office Assistant (1)

HR & Administration Division SSI division

Store and Inventory Dept.

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Chapter

GAS TURBINE

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A package power plant, as furnished for most installations, is comprised of the single shaft, simple

cycle and heavy duty gas turbine unit driving a generator. Fuel and air are used by the gas turbine

unit to produce the shaft horsepower necessary to drive certain accessories and ultimately the

driven load generator.

The turbine unit is composed of a starting device, support systems, an axial flow compressor,

combustion system components, a three stage turbine. Both compressor and turbine are directly

connected with an in line single-shaft rotor supported by two pressure lubricated bearings. The

inlet end of the rotor shaft is coupled to an accessory gear having integral shaft that drive the fuel

pump, lubrication pump and other system components.

2.1 Functional Description of the turbine:

When the turbine starting system is actuated and the clutch is engaged, ambient air is drawn

through the inlet plenum assembly, filtered, then compressed in the 17th stage, axial flow

compressor. For pulsation protection during start-up, the 11th stage extraction valves are open and

the variable inlet guide vanes are in the closed position. When the speed relay corresponding to 95

per cent speed actuates, the 11th stage extraction bleed valves close automatically and the variable

inlet guide vane actuator energizes to open the inlet guide vanes (I.G.V.) to the normal turbine

operating position. Compressed air from the compressor flows into the annular space surrounding

the fourteen combustion chambers, from which it flows into the spaces between the outer

combustion casings and the combustion liners. The fuel nozzles introduce the fuel into each of the

fourteen combustion chambers where it mixes with the combustion air and is ignited by both (or

one, which is sufficient) of the two spark plugs. At the instant one or both of the two spark plugs

equipped combustion chambers is ignited, the remaining combustion chambers are also ignited by

crossfire tubes that connect the reaction zones of the combustion chambers. After the turbine rotor

approximates operating speed, combustion chamber pressure causes the spark plugs to retract to

remove their electrodes from the hot flame zone.

The hot gases from the combustion chambers expand into the fourteen separate transition pieces

attached to the aft end of the combustion chamber liners and flow towards the three stage turbine

section of the machine. Each stage consists of a row of fixed nozzles followed by a row of rotatable

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turbine buckets. In each nozzle row, the kinetic energy of the jet is increased, with an associated

pressure drop, and in each following row of moving buckets, a portion of the kinetic energy of the

jet is absorbed as useful work on the turbine rotor. After passing through the 3rd stage buckets, the

exhaust gases are directed into the exhaust hood and diffuser which contains a series of turning

vanes to turn the gases from the axial direction to a radial direction, thereby minimizing exhaust

hood losses. Then, the gases pass into the exhaust plenum. The resultant shaft rotation is used to

turn the generator rotor, and drive certain accessories. By definition, the air inlet of the gas turbine

is the forward end, while the exhaust end is the aft end. The forward and aft ends of each

component are determined in like manner with respect to its orientation within the complete unit.

The RIGHT and LEFT sides of the turbine or of a particular component are determined by standing

forward and looking aft.

Fig.2.1 Gas Turbine Simple Cycle Diagram

2.2 Air Filter:

Numerous components in a gas turbine power plant affect fuel consumption and plant efficiency.

Filters can have a direct, often significant effect on the efficiency of the turbine itself. A more

efficient turbine can result in lower fuel usage and consequently lower fuel costs, as well as

reduced carbon dioxide emissions. A filter acts as a selective barrier for combustion air. It allows

air and dust particles of a certain size to pass through but stops the bigger dust particles. As filters

become more efficient and less dust gets through, it is more difficult for air to penetrate the filter.

This resistance to the air flow results in a pressure drop, which directly affects the performance of

the turbine. The higher the pressure drop, the higher the fuel consumption for the same power

output or the lower the power output for the same fuel consumption.

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Fig. 2.2 Conical cylindrical filter (a) one unit (b) assembly (c) pocket filter

2.3 Compressor Section:

The axial-flow compressor section consists of the compressor rotor and the inclosing casing.

Included within the compressor casing are the inlet guide vanes, the 17 stages of rotor and stator

blading, and the exit guide vanes. In the compressor, air is confined to the space between the rotor

and stator blading where it is compressed in stages by a series of alternate rotating (rotor) and

stationary (stator) airfoil shaped blades. The rotor blades supply the force needed to compress the

air in each stage and the stator blades guide the air so that it enters in the following rotor stage at

the proper angle. The compressed air exits through the compressor discharge casing to the

combustion chambers. Air is extracted from the compressor for turbine cooling, for bearing

sealing, and during startup for pulsation control. Since minimum clearance between rotor and

stator provides best performance in a compressor, parts have to be made and assembled very

accurately.

(a) (b) (c)

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Fig. 2.3 Axial flow compressor

2.3.1 Compressor Rotor:

The compressor rotor is an assembly of 15 individual wheels, two stub-shafts, each with an integral

wheel, a speed ring, tie bolts, and the compressor rotor blades. Each wheel and the wheel portion

of each stub-shaft has slots broached around its periphery. The rotor blades and spacers are inserted

into these slots and are held in axial position by staking at each end of the slot. The wheels and

stub-shafts are assembled to each other with matching rabbets for concentricity control and are

held together with tie bolts. Selective positioning of the wheels is made during assembly to reduce

balance correction. After assembly, the rotor is dynamically balanced to a fine limit.The forward

stub-shaft is machined to provide the forward and aft thrust faces and the journal for the n 1

bearing, as well as the sealing surfaces for the n 1 bearing oil seals and the compressor low

pressure air seals.

2.3.2 Compressor stator:

The stator (casing) area of the compressor section is composed of four major sections:

Inlet casing

Forward compressor casing

Aft compressor casing

These sections, in conjunction with the turbine shell and exhaust frame form the primary structure

of the gas turbine. They support the rotor at the bearing points and constitute the outer wall of the

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gas path annulus. The casing bore is maintained to close tolerances with respect to the rotor blade

tips for maximum efficiency.

The inlet casing is located at the forward end of the gas turbine. Its prime function is to uniformly

direct air into the compressor. The inlet casing also supports the n 1 bearing housing, a separate

casting that contains the n 1 bearing. The n 1 bearing housing is supported in the inlet casing on

machined surfaces on either side of the inner bell mouth of the lower half casing. To maintain axial

and radial alignment with the compressor rotor shaft, the bearing housing is shimmed, doweled

and bolted in place at assembly.

The inner bell mouth is positioned to the outer bell mouth by eight airfoil-shaped radial struts that

provide structural integrity for the inlet casing. The struts are cast into the bell mouth walls.

2.3.3 Variable inlet guide vanes:

Variable inlet guide vanes are located at the aft end of the inlet casing. The position of these vanes

has an effect on the quantity of compressor air flow. Movement of these guide vanes is

accomplished by the inlet guide vane control ring that turns individual pinion gears attached to the

end of each vane. The control ring is positioned by a hydraulic actuator and linkage arm assembly.

Fig. 2.4 Inlet Guide Vane

2.3.4 Forward casing:

The forward compressor casing contains the first four compressor stator stages. It also transfers

the structural loads from the adjoining casing to the forward support which is bolted and doweled

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to this compressor casing's forward flange. The forward compressor casing is equipped with two

large integrally cast trunnions which are used to lift the gas turbine when it is separated from its

base.

2.3.5 Aft casing:

The aft compressor casing contains the fifth through tenth compressor stages. Extraction ports in

the casing permit removal of 5th and 11th stage compressor air. This air is used for cooling and

sealing functions and is also used for starting and shutdown pulsation control.

2.3.6 Discharge casing:

The compressor discharge casing is the final portion of the compressor section. It is the longest

single casting. It is situated at the midpoint between the forward and aft supports and is, in effect,

the keystone of the gas turbine structure.

The functions of the compressor discharge casings are to contain the final seven compressor stages,

to form both the inner and outer walls of the compressor diffuser and to join the compressor and

turbine stators. They also provide support for n 2 bearing, the forward end of the combustion

wrapper, and the inner support of the first-stage turbine nozzle. The compressor discharge casing

consists of two cylinders, one being a continuation of the compressor casings and the other being

an inner cylinder that surrounds the compressor rotor. The two cylinders are concentrically

positioned by twelve radial struts. These struts flair out to meet the larger diameter of the turbine

shell, and are the primary load bearing members in this portion of the gas turbine stator. The

supporting structure for bearing is contained within the inner cylinder. A diffuser is formed by the

tapered annulus between the outer cylinder and inner cylinder of the discharge casing. The diffuser

converts some of the compressor exit velocity into added pressure.

2.3.7 Blading:

The compressor rotor and stator blades are airfoil shaped and designed to compress air efficiently

at high blade tip velocities. The blades are attached to their wheels by dovetails arrangements.

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The dovetail is very precise in size and position so as to maintain each blade in the desired

position and location on the wheel.

Fig. 2.5 Schematic diagram of the compressor section

The compressor stator blades are airfoil shaped and are mounted by similar dovetails into ring

segments. The ring segments are inserted into circumferential grooves in the casing and are held

in place with locking keys. The stator blades of the last nine stages and two exit guide vanes have

a square base dovetail that are inserted directly into circumferential grooves in the casing. Locking

keys also hold them in place.

2.4 The combustion system:

The combustion system is the reverse flow type which includes 10 combustion chambers having

following components:

liners,

Flow sleeves,

Transition pieces

Cross fire tubes.

Flame detectors,

Hot gases, generated from burning fuel in the combustion chambers are used to drive the turbine.

In the reverse flow system, high pressure air from the compressor discharge is directed around the

liner wall and impinges against rings that are brazed to the liner wall. This air then flows right

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toward the liner discharge end and forms a film of air that shields the liner wall from the

combustion gases. Fuel is supplied to each combustion chamber through a nozzle. Combustion

chambers are numbered counterclockwise when viewed looking down stream and starting from

the top of the machine. The ten combustion chambers are interconnected by means of crossfire

tubes. These tubes enable flame from fired chambers containing spark plugs to propagate to the

unified chambers.

2.5 Turbine section:

The three stage turbine section is the area in which energy in the form of high energy, pressured

gas produced by the compressor and combustion sections is converted to mechanical energy. Each

turbine stage is comprised of a nozzle and the corresponding wheel with its buckets. Turbine

section components include the turbine rotor, turbine shell, nozzle, shrouds, exhaust frame and

exhaust diffuser.

2.5.1 Turbine Base:

The base upon which the gas turbine is mounted is a structural-steel fabrication of welded steel

beams and plate. It forms a single platform which provides support upon which to mount the gas

turbine. In addition, the base supports the gas turbine inlet and exhaust plenums. Lifting trunnions

and supports are provided, two on each side of the base in line with the structural cross members

of the base frame. Machined pads, three on each side of the bottom of the base, facilitate its

mounting to the side foundation. Two machined pads, atop the base frame are provided for

mounting the aft turbine support. The gas turbine is mounted to its base by vertical supports. The

forward support is located at the lower half of the vertical flanges of the forward compressor

casing, and the aft two support-legs are located on either side of the turbine exhaust frame.

The forward support is a flexible plate that is bolted and doweled to the turbine base, at the forward

base cross frame beam, and bolted and doweled to the forward flanges of the forward compressor

casing. The aft supports are leg-type supports, located one on each side of the turbine exhaust

frame. Both vertical support legs rest on machined pads on the base and attach snugly to the turbine

exhaust-frame-mounted support pads. The legs provide center-line support to supply casing

alignment. Fabricated to the outer surface of each aft support leg is a water jacket. Cooling water

is circulated through the jackets to minimize thermal expansion of the support legs and assist in

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maintaining alignment between the turbine and the generator. The support legs maintain the axial

and vertical positions of the turbine, while a key coupled with the turbine support legs maintains

its lateral position.

Fig. 2.6 Gas turbine base

2.5.2 Turbine rotor:

The turbine rotor consists of the distance piece, first stage wheel, first and second stage spacer,

second stage wheel, second and third stage spacer, third stage wheel and aft wheel shaft. It is mated

to the compressor rotor by bolted flange connection of the compressor seventeenth stage wheel,

thus connecting the distance piece to the wheel.

2.5.3 Buckets:

The turbine buckets increase in size from the first to the third stage. Because of the pressure

reduction resulting from energy conversion in each stage, an increased annulus area is required to

accommodate the gas flow; thus the increasing size of the buckets. The first stage buckets are the

first rotating surfaces encountered by extremely hot gases leaving the first stage nozzle. Each first

stage bucket contains a series of longitudinal air passages for bucket cooling. Air is introduced

through four cooling holes in the bucket dovetail and it flows towards the bucket tip where it exits.

The tips of these buckets are enclosed by a shroud which is a part of the tip seal. The shroud

interlock from bucket to bucket to dampen vibration.

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The three stage turbine buckets are attached to their wheels by straight, axial entry, multiple tang

dovetails that fit into matching counts in the rims if the turbine wheels. The turbine rotor assembly

is arranged so that the buckets can be replaced without unstacking the wheels, spacers and wheel

shaft assemblies.

Fig. 2.7 Three stages of buckets

2.5.4 Turbine stator:

The turbine shell and the exhaust frame complete the major portion of the gas turbine stator

structure.

2.5.5 Turbine shell:

The turbine shell controls the axial and radial position of the shrouds and nozzles. Resultantly, it

controls turbine clearances and the relative positions of the nozzles to the turbine buckets. This

positioning is critical to the turbine performance.

Hot gases contained by the turbine shell are a source of heat flow into the shell. To control the

shell diameter, it is important to reduce the heat flow into the shell by design and to cool it to limit

its temperature. Heat flow limitations incorporate insulation, cooling and multilayered structures.

2.5.6 Turbine nozzles:

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In the turbine section, there are threestages of stationary nozzles which direct the highvelocity flow

of the expanded hot combustion gas against the turbine buckets, causing the rotor to rotate. Because of

the high pressure drop across these nozzles, there are seals at both the inside diameters and the outside

diameters to prevent loss of system energy by leakage. Since these nozzles operate in the hot combustion

gas flow, they are subjected to thermal stresses in addition to gas pressure loadings.

First stage nozzle: The firststage nozzle receives the hot combustion gases from the

combustion system via the transition pieces. The transition pieces are sealed to both the outer and

inner sidewalls on the entrance side of the nozzle minimizing leakage of compressor discharge

air into the nozzle. The 18 cast nozzle segments, each with two partitions (or airfoils) are contained

by a horizontally split retaining ring which is center line supported to the turbine shell on lugs at

the sides and guided by pins at the top and bottom vertical center lines. This permits radial growth of

the retaining ring, resulting from changes in temperature while the ring remains centered in the

shell. The aft outer diameter of the retaining ring is loaded against the forward face of the first

stage turbine shroud and acts as the air seal to prevent leakage of compressor discharge air

between the nozzle and shell. On the inner sidewall, the nozzle is sealed by U shaped seal

segments installed between the nozzle and the first stage nozzle support ring bolted to the

compressor discharge casing. The nozzle is prevented from moving forward by four lugs welded

to the aft outside diameter of the retaining ring at 45 degrees from vertical and horizontal center

lines. These lugs fit in a groove machined in the turbine shell just forward of the first stage shroud

Thook. By removing the horizontal joint support block and the bottom center line guide pine,

the lower half of the nozzle can be rolled out with the turbine rotor in place. The first stage

nozzle partitions are internally cooled by compressor discharge air.

Second stage nozzle :

Combustion gas exiting from the first stage buckets is again expanded and redirected against

the secondstage turbine buckets by the second stage nozzle. The second stage nozzle is made

of 16 cast segments, each with three partitions (or airfoils). The male hooks on the entrance and

exit sides of the sidewall fit into female grooves on the aft side of the first stage shrouds and on

the forward side of the second stage shrouds to maintain the nozzle concentric with the turbine

shell and rotor. This close fitting tongue and groove fit between nozzle and shrouds acts as an

outside diameter air seal. The nozzle segments are held in a circumferential position by radial

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pins from the shell into axial slots in the nozzle outer side-wall. The second stage nozzle

partitions are cooled with compressor discharge air.

Thirdstage nozzle :

The thirdstage nozzle receives the hot gas as it leaves the second stage buckets, increases its

velocity by pressure drop and directs this flow to impinge against the third stage buckets. The

nozzle consists of 16 cast segments, each with four partitions (or airfoils). It is held at the outer

sidewall forward and aft sides in grooves in the turbine shrouds in a manner identical to that

used on the second stage nozzle. The third stage nozzle is circumferentially positioned by radial

pins from the shell.

2.6 Gas fuel system:

Gas fuel is first cleaned by passing through a strainer as it comes from the supply piping, prior to

flowing through the gas valve and into the gas manifold piping. The gas fuel is metered and controlled

by the gas valve (gas stop/ratio and control valve) to supply the required flow to the gas turbine

combustion system.

2.6.1 Gas strainer:

A gas strainer is installed upstream of the turbine base fuel inlet connection point, to facilitate site

maintenance requirements. Connection of the fuel gas supply is made at the purchaser's connection in

the supply line ahead of the gas strainer. Foreign particles that may be in the incoming fuel gas are

removed by the strainer.

2.6.2 Gas stop/ratio and control valves:

The gas stop ratio and control valve consists of two independent valves (a stop ratio valve and a control

valve) combined into one housing assembly. Both the gas stop ratio valve and the gas control valve are

singleaction, electrohydraulic operated. The symbols of the corresponding hydraulic servo valves are

respectively 90 SR and 65 GC in the piping diagrams.

The gas stop ratio valve is used to shut off fuel flow to the turbine whenever required. It also controls the

pressure ahead of the fuel gas control valve. This enables the gas control valve to control fuel flow over

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the wide range required under turbine starting and operating conditions. The fuel gas control valve is

activated by a SPEEDTRONIC control signal to admit the proper amount of fuel required by the

turbine for a given load or speed.The gas control valve part of the gas stop/ratio and control valve

provides a gas fuel metering function to the turbine in accordance with its speed and load requirements.

The position of the gas control valve (hence fuel gas flow to the turbine) is a linear function of a variable

control voltage (FSR) generated by the SPEEDTRONIC control. The control voltage generated acts to

shift the electrohydraulic servo valve to admit oil to or release it from the hydraulic cylinder to position

the gas control valve so that the fuel gas flow is that which is required for a given turbine speed and a

load situation.

The gas stop ratio valve is similar to the gas control valve. Its plug, however, has a steeper taper to

provide the high gain necessary to maintain good pressure control. The ratio function of the stop ratio

valve provides a regulated inlet pressure for the control valve as a function of turbine speed. The

SPEEDTRONIC pressure control loop generates a position signal to position the stop ratio valve by

means of a servo valve controlled hydraulic cylinder to provide required intervalve pressure.

The gas stop ratio valve functions in the fuel gas system to provide a positive fuel shutoff when required

by either normal or emergency conditions. A gas fuel trip valve is operated by trip oil pressure acting

on the piston end of a spool. When the trip oil pressure is normal the gas fuel trip valve VH 5 is held

in a position that allows hydraulic oil to flow between the control servo valve and the hydraulic cylinder.

In this position, normal control of the stop ratio valve is allowed. In event of a drop in trip oil pressure

below a predetermined limit, a spring in the trip valve shifts the spool to interrupt the flow path of oil

between the control servo valve and the hydraulic cylinder. Hydraulic oil is dumped and the stop ratio

valve closes, shutting off fuel gas flow to the turbine.

2.6.3 The cooling and sealing air system:

Provides the necessary air flow from the gas turbine compressor to other parts of the gas turbine

rotor and stator to cool these parts during normal operation. When the gas turbine is operating, air

is extracted from the two stages of the axial flow compressor as well as from the compressor

discharge. It is used to provide the following cooling and sealing functions:

Seal the turbine bearings.

Cool the internal parts.

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Cool the turbine outer shell and exhaust frame.

Provide an operating air supply for the air-operated valves.

Compressor pulsation protection.

Provide pulse air to the self-cleaning inlet air filters.

Specially designed air passages are fabricated in the turbine casing, turbine nozzles and rotating

wheels. Functional description Air extracted from the fifth stage and eleventh stage of the axial

flow compressor and from the compressor discharge is used for sealing the bearings and cooling

internal turbine parts. It is also used after filtration to provide a clean air supply for air-operated

control valves of other systems. Bearing sealing air is extracted from the fifth and eleventh stage

of the compressor. Internal cooling air, identified as sixteenth-stage extraction air, is extracted

from the compressor discharge. It provides an internal flow of cooling air through the center of the

turbine rotor. Air used as the operating air supply for the air-operated extraction valves is extracted

from the discharge of the compressor. Besides, two motor driven centrifugal blowers mounted

external to the turbine itself, supply cooling air for the turbine shell, then the exhaust frame and its

support struts, and the aft side of the third stage turbine wheel.

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Chapter

Heat Recovery Steam Generator

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Heat recovery steam generator or HRSG is an energy recovery heat exchanger that recovers heat

from a hot gas stream. They can be operated in either Co-generation mode or the combined cycle

mode. In the Co-generation mode, steam produced from the HRGS is mainly used for process

application, whereas in combined cycle mode, power is generated via steam generator. In the

combined cycle mode, the efficiency of the combined gas turbine and HRSG system can reach

55%-60%. Heat Recovery Steam Generator (HRSG) boiler is very useful to improve efficiency of

fuel that is used in gas turbine unit, which will further drive steam turbine unit.

Fig.3.1 Exhaust gases from the gas turbine passes through the HRGS to produce steam

Figure 3.1 shown above describes the basic process of steam and Power generation. The HRGS

generates steam utilizing the energy in the exhaust from the gas turbine.

In a Combined Cycle power plant Gas turbine and Steam turbine is used for power production.

Steam turbine uses steam to produce power. HRGS is the major parts of the steam system. It is

used to produce steam.. It produces steam that can be used to drive a steam turbine. The exhaust

gas temperature from a Gas Turbine is about 580 C.

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3.1 Components of HRSG

The principal components if HRSG are:

Super Heater

Evaporator

Economizer

Pre-heater

Drum

3.1.1 Super heater

The super heater is one of HRSG components that serve to raise temperature of saturated steam to

be superheated steam. It is the most important accessories of boiler that improves the thermal

efficiency. Super heater is installed where temperature is higher, i.e. at the entrance of exhaust

gases. Superheated steam when used to perform work by way of expansion in the turbine or steam

engine will not condense, thus reducing the possibility of danger.

3.1.2 Evaporator

Evaporator is one of HRSG components which serve to convert water into saturated steam. The

preheated water from the economizer is converted into steam by evaporator. Water/steam

circulates from lower drum to steam drum. Evaporator will heat water that falls from steam drum

which still in liquid phase to form the saturated steam so it can be forwarded to super heater.

3.1.3 Economizer

Economizer is one of HRSG components that consist of water pipes that are placed on the track of

flue gases after evaporator pipes. Economizer pipes are made of steel or cast iron materials that

are able to withstand high heat and pressure. Economizer serves to heat feed water before it enters

the steam drum and evaporator. Furthermore the evaporation process can be easier by using high

temperature flue gas of HRSG so increase the efficiency of HRSG because it can reduce heat loss

in the Heat Recovery Steam Generator (HRSG). Water which enters the evaporator is at high

temperature so evaporator pipes are not easily damaged due to difference in temperature is not too

high.

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3.1.4 Pre-heater

Pre-heater is one of HRSG components that serves as initial heater of water which is pumped

from condenser before enter into feed water tanks. In the HRSG system, pre-heater serves to raise

temperature before enter feed water tanks which later will be forwarded to economizer.

Fig. 3.2 (a) Super heater (b) Evaporator (c) Economizer

3.2 Overview of HRSG unit

(a) (a) (b) (c)

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The power plant has 4 heat recovery steam generator. Each Heat recovery steam generator

produces two types of steam-high pressure steam and low pressure steam. High pressure steam

enters in one common header which is called high pressure line. Similarly Low pressure steam

enters in one common header which is called Low pressure line. Adding Additional pressure level

in the HRSG can increases the amount of heat that can be recovered from the exhaust gas. So, in

order to extract more energy from exhaust gas, both HP and LP steam are produced. HRSG can be

classified in many ways, such as exhaust gas flow, the number of pressure levels or whether the

flue gases or water passes through the tube, etc. The HRGS used in this power plant is vertical and

water tube and dual pressure boiler. The tubes contain water and are surrounded by the high

temperature exhaust gases. The HRSG consists of 2 HP super heater, 2 HP Economizer, 1 HP

Evaporator,1 LP superheater,1 LP Economizer and 1 Evaporator. There are 3 pumps used for

supplying water to the Economizer. Among the three, 2 of them are always running. Another one

is kept standby. There are 3 types of tank named HP drum, LP drum and Feed water tank. Blow

down is done periodically by blow down vessel. Boiler blow down is water intentionally wasted

from a boiler to avoid concentration of impurities during continuing evaporation of steam. The

water is blown out of the boiler with some force by steam pressure within the boiler. Bottom blow

down used with early boilers caused abrupt downward adjustment of boiler water level and was

customarily expelled downward to avoid the safety hazard of showering hot water on nearby

individuals.

HRSG can supply steam at 520 degree Celsius. If by chance steam temperature rises above 520

degree Celsius water is sprayed in steam to reduce temperature. The water sprayed is supplied

from Economizer. The material used for the heat recovery steam generator should be able to

withstand high temperature and pressure. The material should have high strength. The feed water

used in HRSG should be properly treated. Water treatment unit is used for these purposes. In this

power plant there are a sophisticated, specialized water treatment unit which ensures better quality

water supplied to the HRSG. This leads to increase in HRSG life.

A schematic diagram of HRSG has been shown in Figure 3.4 which has been obtained from mark5

console.

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Fig. 3.3 Schematic diagram Steam generation

Fig. 3.4 Schematic diagram of HRSG

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3.3 Water Treatment Unit:

Cost competitive and environment friendly technology innovated and developed through

continuous research to keep industry green and competitive. Excellence in technology and

stringent quality control measures are the hallmarks in all projects undertaken by Waste Solutions

Division. Waste solutions division takes on Retrofitting and Revamping orders to extend life of all

aging plants. Besides it enhances the economic performance of all water & waste treatment plants.

Chemically speaking water is H2O, the combination of two parts of Hydrogen to one part of

Oxygen. Absolutely pure water is impossible to obtain in the nature. Pure water does not exist in

nature due to its characteristic as solvent. Number of matters like gases, minerals and organic

materials dissolve in the water easily. It picks up fine particles wherever it flows such as silt, sand,

iron and organics etc. Biological growths like algae and bacteria take place in the water. Thus,

water is usually contaminated with numerous dissolved and un-dissolved solids along with living

matters.

An effective Water Treatment Unit is provided in Mymensingh Power Station (MPS). The Whole

Water Treatment Unit is divided into four categories as stated below:

Pre-Treatment System

Demineralization System

Chemical Storage and Neutralization

Waste water system.

3.3.1 Pre-Treatment System:

Raw water extracted from underground by the Deep Well Pump contains various types of minerals

and salts of Ferrous, Calcium, Magnesium ions. The water is then passed through the Aeration

Tank where oxidation of Fe, reduction of Ammonium Sulfate and removal of CO2 take place from

raw water. At the same time, Poly Aluminum Chloride (PAC) dosing is done for enlarging the

foreign particles carried by the raw water. After PAC dosing the water is passed through the

Multimedia Filter having a bed of three layers to remove the colloidal and suspended particles in

water. The upper layer of the bed is Anthracite, middlesand and the lastgravel. After an

approximate 12 hour running period, multimedia filter goes to backwash to improve

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Deep Well

Water

Aeration

Tank

PAC

Dosing

Multimedia

Filter

NaOCl

Dosing

Filtered

Water Tank

Cation

Exchanger-1

Anion

Exchanger-

2

CO2 degasify-1

Filtered

Tank

Intermediate

Tank

Cation

Exchanger-2

Anion

Exchanger-

2

CO2 degasify-

2

Ultra-filtration

Rack-1

Ultra-filtrate

Tank

Ultra-filtration

Rack-2

Mixed-bed

Filter 1 & 2

Demi Water

Tank

Condensate

Tank

Fig. 3.5 Flow chart for water pre-treatment System

Fig. 3.6 Flow chart for demineralization system

Boiler

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Waste

Water

Coagulation

Tank

Flocculation

Tank

Lamella

Separator

Filter

Press

pump

Environment

filtration process. NaOCI is dosed in water before entering into Filtered Water Tank against

microbiological growth. The flow chart for pretreatment is shown in Figure 3.5.

3.3.2 Demineralization System:

Demineralization or deionization is the process of removing mineral salts from water by using the

ion exchange process. With most natural water sources it is possible to use demineralization and

produce water of a higher quality than conventional distillation. Demineralization involves two

ion exchange reactions. Initially, the Cation such as calcium magnesium and sodium are removed

by Hydrogen ion (H+). The salts thus converted into their respective acids by this exchange. The

Fig. 3.7 Flow chart for waste water treatment system

Fig. 3.8 Multi media filter

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acidic water is then passed through an Anion exchange where the anions such as sulfates chlorides

etc. are removed by Hydroxyl (OH-) ions.

Demineralization system consists of Cation Exchanger (1 & 2), Anion Exchanger (1 & 2), CO2

degasify (1 & 2), Intermediate Tank, Ultra filtration Rack (1 & 2) and Ultra-filtrate Tank. The pH

of filtrated water is about 7 (6.9 - 7.1) which is neutral. When this water passes through Cation

exchanger, Cations like Ca2+, Mg2+, Na+, K+, NH4+ and traces of heavy metals are exchanged

through Cation resin decreasing the value of pH 4 5. When water passes through Anion

exchanger, Anions like SO42-, NO3

-, Cl-, PO4- and dissolved SiO2 are exchanged through anion

resin and pH of water then becomes about 7. The conductivity and pH is continuously checked in

an automated system. Maximum allowable conductivity 1.20 S/cm. Above this limit,

regeneration of resin have to operate. 20% H2SO4 is used for Cation resin and 50% NaOH is used

for anion resin for regeneration. CO2 degasify is used for removing carbon dioxide from the water

after being processed in Ion Exchanger. Then the water is collected in a tank named Intermediate

Tank. The most fantastic Water Treatment part of Mymensingh Power Station (MPS) is the

Ultrafiltration which is the process of separating colloidal silica from water coming from

intermediate tank by means of ultrafiltration membranes. After every 2 hour ultrafiltration rack

goes to backwash where 10th backwash is caustic backwash. 50% NaOH use for caustic backwash.

After the treatment from the Ultrafiltration Tank the water is stored in Ultra filtrate Tank. Cation

and Anion resin remain in mixed condition in Mixed Bed Filter. The remaining ions that are not

separated by the previous processes are exchanged here from water coming from Ultra-filtrate

Tank. 20% H2SO4 is used for Cation resin and 50% NaOH is used for anion resin for regeneration

of resin in the Mixed Bed Filter. Then Demi water whose pH is 7 is produced and stored in the

Condensate Tank.

3.3.3 Chemical Storage and Neutralization:

1. H2SO4 98% Storage Tank: Store acid used for Regeneration of C/A L-1, C/A L-2, MBF-1 & MBF-2 and backwash of Aeration tower . 98 % H2SO4 from storage tank and water from

DI water tank are used to make concentration of 20% H2SO4 for regeneration, which is

stored in measuring tank.

2. NaOH 50% Storage Tank: Caustic storage for Regeneration of C/A L-1, C/A L-2 , MBF-1 & MBF-2 and Backwash of Ultra filtration Rack-1&2 .

3. NaOH 50% Measuring Tank: Caustic storage from NaOH 50% storage tank for one regeneration.

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4. Neutralization Tank: Collect regeneration waste water. Waste water is neutralized to a pH between 6 to 9 before discharging.

3.3.4 Waste Water Treatment:

Suspended particles cannot be removed completely by plain settling. Large, heavy particles settle

out readily, but smaller and lighter particles settle very slowly or in some cases do not settle at all.

Because of this, the sedimentation step is usually preceded by a chemical process known

as coagulation. Chemicals (coagulants) are added to the water to bring the non-settling particles

together into larger, heavier masses of solids. Aluminum Sulfate is the most common coagulant

used for water purification. Other chemicals, such as ferric sulfate or sodium aluminate, may also

be used. Coagulation is usually accomplished in two stages: rapid mixing and slow mixing. Rapid

mixing serves to disperse the coagulants evenly throughout the water and to ensure a complete

chemical reaction. Sometimes this is accomplished by adding the chemicals just before the pumps,

allowing the pump impellers to do the mixing. Usually, though, a small flash-mix tank provides

about one minute of detention time. After the flash mix, a longer period of gentle agitation is

needed to promote particle collisions. This gentle agitation, or slow mixing, is called flocculation

it is accomplished in a tank that provides at least a half hour of detention time. The flocculation

tank has wooden paddle-type mixers that slowly rotate on a horizontal motor-driven shaft. After

flocculation the water flows into the sedimentation tanks. Some small water-treatment plants

combine coagulation and sedimentation in a single prefabricated steel unit called a solids-contact

tank.

1. Waste Water Pit: Collect waste water from UF Backwash, ACC, MMF Backwash, MBF

Backwash and outside area.

2. Coagulation Tank: Collect water from waste water pit. It is an over flow tank.

3. Flocculation Tank: Collect water from coagulation tank. It is an over flow tank.

4. Lamella Separator: In lamella separator, separation and concentration of suspended matter

will take place to form sludge.

5. Filter Press Pump: Collect water from lamella separator and then pumped to filter press for

removing sludge.

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Chapter

Steam Turbine & Electricity distribution

4

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The turbine is a condensing turbine with normal main steam parameters, an inlet casing with an

overall dimension of 90 and an exhaust steam casing with and overall dimension of 3.2 m2 with

axial exhaust flow.

The main steam expands in the turbine and flows axially into the condenser where it condenses.

The turbine itself is a subcomponent of the overall turbine-generator unit, which includes other

components such as oil supply unit, condensing plant, generator and the I&C system.

The Steam turbine consists of:

Steam Turbine

Basic turbine with inner casing

Rotor

Stationary Blade Carrier

Shaft Glands

Bearing Support Systems

Control System

Instrumentation

Positioning system for control and limitation

Protective and limiting devices

Oil supply system

Oil tank with oil tank heater

Oil pumps with three-phase a.c. motor

Emergency oil input, d.c. motor

Oil cooler with changeover value

Oil filter for lube and control oil

Lifting oil system with lift oil pump and lift oil filter

Oil purification system

Oil mist separator

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Internal Steam Lines

Seal Steam pressure control

Gland steam desuperheater

Drain header with hotwell and condensate pump

Accessories

Seal steam control system

Seal-steam condenser

Electric Turning gear

Safety valve , atmospheric exhaust

Casing heating system

Electrical and I&C system

Generator

Turbine I&C system

Generator Control circuit

Voltage regulator

Power supply system

Turbine sub-distribution system

24 V DC power supply

4.1 Operating principle

The steam passes through the main steam connection, the steam strainer and emergency stop valve

before the servo valves into inlet part of the outer casing. After opening of the servo valves, the

steam flows into the steam chamber, to pass through the jet groups into the expansion area of the

turbine, by giving off its energy capacity and expanding up to the final pressure in the exhaust part.

Function and key design considerations of some components of interest are as follows:

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4.2 Steam Turbine Components

4.2.1 Turbine Casing:

The turbine casing acts as the outer shell for the steam space of the turbine and accommodates

the internal steam flow components and turbine control system. The turbine casing is split

horizontally and made of high-temperature cast steel.

4.2.2 Inner casing

Together with the main steam inlet, the inner casing forms the control stage and the integrated

stationary blading for the first expansion space (EBI) of the turbine.

4.2.3 Sealing Shells

The sealing shells serve the purpose of sealing between the outer casing and rotor on the steam

end. Besides sealing against internal excess pressures, the ingress of ambient air in the event of

an internal partial vacuum must be reliably prevented. Depending on the arrangement of the

sealing plates of the rotor and shell, the sealing shells form a contact-free labyrinth or "peak-

peak" seal. The sealing shell is of great importance because it ensures the thermal efficiency of

the steam turbine plants.

The sealing effect is based on the principle of conversion of pressure energy to velocity energy

followed by eddying. The gap between rotary and static elements and the design as a labyrinth or

peak-peak seal has a crucial influence on its effectiveness.

The steam passes through sealing shells that seal off against internal excess pressure from

the inside to the outside. Through the slits in the sealing shell body. leaking steam is

sucked out of the shell after the inner area. A small amount of steam passes through the

middle area into the subsequent collecting space and, from there, through the opening

in the top shell and the connected vapor line into the atmosphere.

Sealing shells that are intended to ensure a partial vacuum in the turbine casing must

prevent the ingress of ambient air into the casing. This is why sealing steam with a slight

excess pressure is passed through the slits in the sealing shell body. The sealing steam

splits into two portions. Corresponding to the larger pressure gradient. The main portion

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flows towards the inside, while a lesser portion passes through the middle area into the

steam collecting space and further through the vapor line into the atmosphere. If required,

steaming of the sealing shell can be adjusted according to the quantity of emerging vapor

steam.

4.2.4 Turbine rotor:

The thermal energy contained in the steam is converted into mechanical energy in the blading. The

turbine rotor and its moving blades transfer this energy as rotational motion to the driven machine.

The basic structure of the turbine rotor is shown in Fig. 1. The number of blade stages shown may

vary in the actual design. The actual turbine shaft comprises a monoblock forging. Steam flows

from the inlet casing and across the control stage (7) and into the first HP nozzle group (6). From

there the flow of steam is rerouted toward the second HP nozzle group (9) and to the LP nozzle

group (10).

The individual regions are sealed against one another by the inner shaft glands (5) as labyrinth

seals (8) or as point-to-point seals. The front shaft gland (4) and the rear shaft gland (13) mark the

ends of the blading region. All shaft gland regions are equipped with caulked-in seal strips. The

rotor is supported in two pressure lubricated journal bearings (3 and 14). The axial position of the

rotor is fixed by the thrust bearing collars (2). Power take-off is provided via a rigid coupling

flange (1), with the turbine, intermediate and generator shafts being connected via coupling bolts.

A drive wheel for an electric or hydraulic rotor turning gear can be integrated between the turbine

and generator shaft. Balancing planes (12) are available at various positions on the rotor.

4.2.5 Turbine Blading:

The thermal energy of the steam is converted into mechanical energy in the blading of the turbine.

The efficiency and the operational reliability of the turbine are crucially dependent on the design

and quality of the blading. Stringent demands are consequently made on the design and

manufacture of the turbine blades. Three different types of blades are employed for the blading.

Nozzle and impulse section profiles for the partially admitted control stage with nozzle group

control. Reaction stage with 50% reaction for the full-admission drum stage as well as throttle-

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controlled turbines which have no control stage. All the blade rows are designed with shroud.

Stainless Cr steel is employed exclusively for the entire blading.

4.2.6 Control Stage

The control stage comprises nozzles and moving blades. The nozzles for the inner casing (steam

chamber) with horizontal casing split are milled in one piece and inserted in slots. Single-piece

inner casings are equipped with a three-piece nozzle ring, which consists of a centre, outer and

inner ring. Using an electro-chemical process, profile-formed openings are created in the centre

ring, into which the corresponding formed profile material is inserted. The centre ring is connected

to the inner and outer ring by electron-beam welding. The moving blades of the control stage

together with the blade shroud and the straddle root are milled in one piece. A two-tongue or three-

tongue straddle root is employed depending on the blade loading. In special cases the blades are

machined directly from the rotor material employing an electro-chemical process. The straddle

roors are inserted into slots of the control stage disk and are secured by means of axial taper pins.

4.2.7 Drum Blading

The guide blades are manufactured from extruded rod stock. They have a hook-type root and are

held apart at the specified pitch in the slot by means of milled spacers inserted into the blade

groove. The spacers are secured by means of taper pins at the joint planes of the guide blade carrier.

The shrouds are riveted to the guide blades. They join a number of guide blades to form sets of

blades. The moving blades of the drum blading together with the inverted 1-root and the blade

shroud are milled in one piece. The inverted t-roots are inserted in slots in the turbine rotor and are

caulked from below using sectional material of brass The form of the blade roots is such that the

contiguously arranged blades have the specified throat openings. The insertion opening of the

blade groove is closed by a locking blade per row. These blades are secured to the turbine rotor by

means of stud screws. Consequently, there is thus neither a gap in the blade ring nor a spacing

deviation.

4.2.8 Sealing of the radial blade

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The radial free clearance between the guide and moving blades fitted with gap shrouds is of the

order of millimeters. Contact between the stationary and moving parts over a large area, e.g. on

deflection of the turbine rotor or of the casing, is thus obviated. This large radial gap is sealed by

means of seal strips in order to reduce the tip clearance losses to a minimum. In the case of the

guide blades, the seal strips are caulked into the turbine rotor, and. in the case of the moving blades,

into the guide blade carrier. The thin seal strips leave a clearance of a few tenths of a millimeter

between the shroud and the turbine rotor on the one hand and between the shroud and the guide

blade carrier, on the other hand.

4.3 Oil Supply System

Oil supply is provided by oil pumps. The pumps guarantee the operating reliability of the turbine,

in particular of the bearings, by ensuring continuous flow and circulation of oil. In addition, the

oil pumps also supply the hydraulic control equipment with the requisite volumes of oil. The oil is

channeled off directly downstream of pressure source and fed to this oil circuit via a filter. The oil

required for supply to the bearings flows through a throttle, the oil coolers and a further duplex oil

filter to the bearings.

4.3.1 Oil pumps

Motor-driven, vertical centrifugal oil pumps are used as the oil pumps, with oil supply provided

by a single pump throughout the course of operation. One oil pump is on continuous standby and

automatically takes over oil supply in the event of failure of the selected duty oil pump. Asa rule,

an electrical oil pump driven by a d.c. motor is used as emergency oil pump for protection of the

bearings. This supplies the bearings with the requisite oil when the other oil pumps are not in

operation. The pump delivery rate is relatively low to match the capacity of the d.c. power source.

For this reason, the hydraulic oil line for this pump is usually connected to the lube oil circuit

downstream of the coolers and filter without dedicated oil cooling and oil filtering systems. The

oil system for the turbine plant is implemented such that in the event of loss of one pump a second

pump will provide a guaranteed supply of oil automatically. Here, it is assumed that the emergency

oil pump never fails, i.e. the power source for the emergency oil pump is always available. For this

reason, proper care and maintenance of the d.c. batteries for example is important to ensure that

these are always ready for use.

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4.3.2 Oil tanks

The oil tank is usually located in front of the turbine. Space restrictions may result in installation

of the oil tank in a separate compartment located below the turbine plant. The oil tank

accommodates the oil required for overall oil supply. The tank is dimensioned and designed such

that the continuously circulating oil in the system can settle somewhat in the tank and so as to

ensure adequate degassing. The vertical oil pumps are mounted on the oil tank cover.

4.4 Air Cooled Condenser

An Air Cooled Condenser (ACC) is a cooling system where the steam is condensed inside air-

cooled finned tubes. An Air Cooled Condenser (ACC) is made of modules arranged in parallel

rows. Each module contains a number of fin tube bundles. An axial flow, forced-draft fan located

in each module forces the cooling air across the heat exchange area of the fin tubes. Due to paucity

of water cooling tower is not used in this plant. There are 15 fans installed in air cooled condenser

unit .Each of the fan consumes 700KW.

Fig. 4.1 Air cooled condenser of MPS

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4.5 Electricity distribution:

Distribution substations connect to the transmission system and lower the transmission voltage to

medium 35 kV with the use of transformer. In the power station 4 step up transformers are used.

Transformer rating is 35/50 MVA. Primary distribution lines carry this medium voltage power

to distribution transformer located near the customer's premises. Distribution transformers again

lower the voltage to the utilization voltage of household appliances and typically feed several

customers through secondary distribution lines at this voltage. Commercial and residential

customers are connected to the secondary distribution lines through service drops. Customers

demanding a much larger amount of power may be connected directly to the primary distribution

level or the sub transmission level. When the demand trips over or below the limited range, the

breaker opens thus protecting the plant equipment.

39

CONCLUSION

I remembered seeing it and it was this metallic turbine and I thought it was beautiful. I had

never been in a power plant before, but I felt, without being overly dramatic, compelled to make

photographs of this for myself- was the impression of John Sexton, an American professor and

educator, on his first ever visit to a power plant. It remains to be a universal feeling that resonates

with everyone having his first exposure to the enormity of life-line these modern civilization-

power plants. Power plants are modern marvels that harness the energy from natural resources

and convert them to the most suitable of forms electric energy. Mymensingh Power Station is

no different. On the bank of river Bramhaputra the power station stands firm as a symbol of hope

and excellence for the locality and the country as a whole, both literally and figuratively. Instead

of being mere switching practices or knob twiddling manipulation, harmonic operations of the

machines have transcended to rather metaphorical communication with them as we experienced

it from the spontaneity of the workforce involved to run the colossal activity in the power station.

It was an experience most necessary for us to know the real world of work where theories meet

implementation, where unforeseen problems pop-up every now and then. We were enriched and

now have a better understanding of our duties as our dreams are better shaped in the daylight of

real engineering. The whole training ushered us to new alleyways of knowledge and whispered

in our hearts that learning never stops.

40

ACKNOWLEDGEMENT

We highly acknowledge the endeavor of Department of Mechanical Engineering, BUET to

accommodate this training program for us. Cordial thank to Dr. Ashiqur Rahman and all the

teachers concerned to coordinate the program. We are also grateful to the engineers and authority

of RPCL Mymensingh Power Station.

41

REFERENCES

1. Operation and Maintenance manual, GE Energy Products Volume-1: Gas Turbine

2. Operation and Maintenance manual, GE Energy Products Volume-2: Gas Turbine

Equipment.

3. Maintenance and Overhaul of Steam Turbine, Siemens.

4. Operation Guide for Mymensingh Power Station, RPCL.

5. System Description of WTU, MPS, RPCL.

6. Balance of Plant, GE, Volume-1.

7. Balance of Plant, GE, Volume-2.

42

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