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BIB-11-GHA-MCD-ISX-001Page:2Of:11

Rev.:0

CLIENT:BANGLADESH POWER DEVELOPMENT BOARD

PROJECT:BIBIYANA SOUTH 400 MW COMBINED CYCLE POWER PLANT

SERVICE WATER SYSTEM CALCULATION REPORT

BIB-11-GHA-MRS-ISX-001Page:1

Of:11

CLIENT:BANGLADESH POWER DEVELOPMENT BOARD

PROJECT:BIBIYANA SOUTH 400 MW COMBINED CYCLE POWER PLANT

SERVICE WATER SYSTEM FUNCTIONAL DESCRIPTION

SERVICE WATER SYSTEM FUNCTIONAL DESCRIPTION

003/11/2014FOR INFORMATION PKSVTBTS

REVDATEPURPOSE OF REVISIONAUTHORREVISEDAPPROVED

TABLE OF CONTENTS

31.PURPOSE

42.GENERAL DESCRIPTION

42.1. System functions

42.1.1. Functions of main control valves

52.2. Equipment list and system limits

52.3. Description

52.3.1. General

62.3.2. Service Water Pumping Group and associated lines

62.4. Emergency and transients

83.SYSTEM INTERFACES

83.1. General

83.2. Support systems

83.3. Dependent systems

94.OPERATION

94.1. General

94.2. Start-up

94.3. Normal operation

104.4. Shutdown

104.5. Emergency stop. Plant trip

104.5.1. Plant trip without auxiliaries voltage loss

104.5.2. Plant trip with auxiliaries voltage loss

115.CONTROL DESCRIPTION

115.1. Analogue and regulation control loop

115.2. Automation and protective logic

125.2.1. Control of service water pumping group (10GHU21/22AP001)

136.EVENTS AND SET POINTS LIST

147.RELATED DOCUMENTS

147.1. Piping and instrumentation diagrams

147.2. Mechanicals

147.3. Instrumentation and control

1. AIMThe aim of this document is to describe the function and physical layout of the Service Water System for the Bibiyana South 400MW CCPP Also, it is defined the system instrumentation and the control and the interfaces with other systems.

2. GENERAL DESCRIPTION2.1. System functions

The Service Water System function is the supply of service water to all the hose points placed throughout the plant, as well as to supply water at Water Treatment Plant for different process purposes.The systems, buildings and equipment in the distribution net that require service water are:

Water Treatment plant Area Electrical Building

Air Compressors Building

Fire Water pump House

Water Pre-Treatment Area

H2 Generation Plant

Fuel gas Compressor Area

ETP Area

Cooling tower Chemical Dosing

Work Shop Building

Ware House Building

ST Area

GT Area

HRSG Area

2.2. Equipment list and system limits

The following equipment is included in this system. For detailed data for each equipment will be provided later, in equipment data sheet.

Two (2) 2x100% Service Water Distribution Pumps

The following equipment is related with the Service Water System but they belong to other system and will be described in the corresponding functional descriptions.

Clarified Water Storage Tank (belongs to the Clarified Water System)

2.3. Description

2.3.1. GeneralThe Service Water Distribution Pump receives water from the Clarified Water System by means of the pipe.This Pump supplies the service water to all the consumption points by means of the main distribution lines all of them in 1 diameter.The main distribution line distributes service water to the above mentioned building or areas.2.3.2. Service Water Distribution Pump and associated linesThe system has two pumps, 2X110% capacity. These pumps belong to a Pressure group with an accumulator tank. The pressure group has a filter in the common suction pipe. Both of the pumps have isolation valves in the suction line as well as the check valve and isolation valve discharge line.

The normal operation is explained in the point 4.3 of this specification. 2.4. Emergency and transients

The events that cause emergencies or transients in the system are identified below:

Loss of automatic system of service water distribution pump. Low low level in Clarified Water Storage Tank. Any trip from the MCC pumping group.3. SYSTEM INTERFACES 3.1. General

In this section it is described the interfaces of the system with other systems or relevant equipment. The interfaces are classified in those that are necessary for the system operation (support systems) and those that are provided by the system and necessary for other systems operation (dependent systems).3.2. Support systems

Mechanical systems

Clarified Water System Electric system for the pumps operation

Distributed control system (DCS)

3.3. Dependent systems

The following equipment / systems are dependents of the correct operation of the system:

Mechanical systems

Water Treatment Plant

All the hose points where service water is required (see point 2.1)

4. OPERATION4.1. General

For the Service Water System operations, the following operational requirements shall be achieved:

All the Drains and Vent valves shall be closed

All the root valves must be opened and the instrumentation available for operation.

MCCs and required electrical devices are energized.

All equipment and instruments properly installed and calibrated.

The Distributed Control System (DCS) is operational

All the alarms and anomalies must be recognized and the equipment qualified in safe condition to operate.

Clarified Water System working properly.4.2. Start-upIf the level in the Clarified Water Storage Tank is below Low level, the Service Water Distribution Pump will not be able to start.

Service Water Distribution pump will start automatically when there is low pressure in line main distribution line due to a service water demand in the service water net.

4.3. Normal operation

Normal operation shall be accomplished by means of the accumulator tank in the Service Water Distribution. During normal operation, one of the pumps shall be working and the other one shall remain on standby mode. The accumulator tank keeps the pressure in the system so that when any of the consumption points require service water it can be supply without starting up the pumps. When there is low pressure after pumps, the pump that is not on standby mode is started.4.4. Shutdown

In the Service Water System shutdown, when there is no demand of service water, the Service Water Distribution Pump can be stopped.4.5. Emergency stop. Plant trip4.5.1. Plant trip without auxiliaries voltage loss

In the event of a Plant trip without auxiliaries voltage loss, Service Water distribution Pump will be completely stopped. Therefore the system is left out of service.4.5.2. Plant trip with auxiliaries voltage loss

In the event of black out, Service Water Distribution Pump will be completely stopped. Therefore the system is left out of service.

5. CONTROL DESCRIPTION The sizing of the main pipes has been developed considering the maximum allowable velocities indicated in the document BIB-10-YM_-MRD-ISX-001 Mechanical Design Criteria.

LinesService Water Main Distribution Line

Pipe spec.1A1

MaterialCarbon Steel

Pipe size1 1/2

Outside diameter(mm)48.3

Thickness (mm)5.08

Inner diameter(mm)38.14

Water Flow4.16 m3/hr

Operation ConditionsCalculated velocity (m/s)Maximum Allowable velocity (m/s)Compliance

Design point1.013ok

LinesConsumption points lines

Pipe spec.1A1

MaterialCarbon Steel

Pipe size3/4

Outside diameter(mm)26.7

Thickness (mm)3.91

Inner diameter(mm)18.88

Water Flow1.2 m3/hr

Operation ConditionsCalculated velocity (m/s)Maximum Allowable velocity (m/s)Compliance

Design point1.193ok

6. SERVICE WATER DISTRIBUTION PUMP

6.1. Principal characteristics

Quantity:2x100%

Place:Near Clarified Water Storage TankType:Horizontal pumpsFluid:Clarified Water6.2. Design point

The service water is produced in the Water Treatment Plant (WTP) .It is filtered water, with the characteristics indicated in the WTP Technical specification.Service water is used for hose connections for the following services:

Water Treatment plant Area Electrical Building

Air Compressors Building

Fire Water pump House

Water Pre-Treatment Area

H2 Generation Plant

Fuel gas Compressor Area

ETP Area

Cooling tower Chemical Dosing

Work Shop Building

Ware House Building

ST Area

GT Area

HRSG Area

For the consumption point design, it has been considered 1.2 m3/h per hose according to the Water Balance Calculation Report and the peak consumption has been determined considering a simultaneity factor of 0,2, also according to the mentioned report. Thus:

Design flow (100%): 4.16 m3/hr6.3. Suction Pump Line

It has been considered the effect on the pressure loss of the piping route with its specialties as valves, elbows and filter according P&ID and Lay Out.

Velocity at suction line (less than)

1.5 m/s 6.4. Pumps Discharge Line

It has been considered the effect on the pressure loss of the piping route with its specialties as valves, elbows etc. according P&ID and Lay Out.

Total pressure drop in pipes

0.982 bar

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