Control Potable Water

8/11/2019 Control Potable Water

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HARYANA POWER GENERATION CORPORATION,PANCHKULA, HARYANA

DESEIN PVT.LTD.

CONSULTING ENGINEERDESEIN HOUSE, GK-IINEW DELHI-110048

CENTRAL ELECTRICITY AUTHORITYSEWA BHAWAN, R K PURAM,NEW DELHI

RELIANCE ENERGY LIMITED,EPC BUSINESS GROUP, NOIDA - 201 301 (U.P.)

DEVELOPMENT CONSULTANTS PRIVATE LIMITEDCONSULTING ENGINEERS24B PARK STREET, KOLKATA - 700 016, INDIA

THERMAX LIMITED WATER & WASTE SOLUTIONSSAI CHAMBERS, 15 MUMBAI-PUNE ROAD,WAKADEWADI,PUNE 411003, INDIA.

REV. NO. DESCRIPTION DATE PREPARED BY CHECKED BY APPROVED BY

0 ISSUED FOR APPROVAL 02.05.2008 RVW SK JK

Owner : HARYANA POWER GENERATION CORPORATION LIMITED

Project : 2 X 600 MW HISAR THERMAL POWER PROJECT

Package : CW,RW & PW CHLORINATION SYSTEM

Drawing / Document No.

REL-HRTPP-VEM-118-J-1024-01

Title :

CONTROL PHILOSOPHY OF CW SYSTEM


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1 8

+91 22 26368185

RUPA

PREP CHKD APPVD

11

0 02.12.2008 Rev.

Rev. No. Date 1

2384-CW- C04-001 CONTROL PHILOSOPHY

Sr. No. Doc. No. Description No. of Sheets

Submission for approval Doc. No.

Remarks 2384-CW- C04-001

TITLE

CONTROL PHILOSOPHY (CW)

No. of Sheets

Contact15 A/J, Laxmi Estate, Andheri,

Mumbai - 400 053

Tel:-

+91 22 26360066

Fax:-

System

Supplier

CW Chlorination System

CAPITAL CONTROLS INDIA PVT.

LTD.

email:

[email protected].

Web:www.capitalcontrolsi

ndia.com

Contractor

DEVELOPEMENT CONSULTANTS PVT. LTD.

RELIANCE ENERGY LTD

System

Consultant

Project

Contract No.

(2x600 MW) CHLORINATION SYSTEM AT HISAR

2384

Work

Client

Design, Engineering, Manufacture & Supply

HARYANA POWER GENERATION CORPORATION


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DOCUMENT No.C.W. CHLORINATION AND ABSORPTION SYSTEM

2384-CW-C04-001-01

(2x600 MW) CHLORINATION SYSTEM AT HISAR Page 1 of 11

Capital Controls India Pvt. Ltd.

CONTROL PHILOSOPHY CW CHLORINATION & ABSORPTION SYSTEM

Rev-01

CONTROL PHILOSOPHY


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1.0 SYSTEM OVERVIEW

To prevent Bio fouling in the condenser, cooling tower and other system components, a chlorinating

system for circulating water system is provided. Also to reduce the organic matter and microorganism

level, chlorinating system for raw water is provided. The system is designed with necessary safety

and supervisory equipment for safe and trouble-free operations of the system, and as per the

specification requirement as detailed below. The following systems are provided:

1. Circulating Water (CW) chlorination and absorption system: Gas Chlorination Plant has been

designed for continuous Dosing of Chlorine at the rate of 3 ppm round the clock in the

circulating water system and shock dosing of 5ppm for 30mins in every shift. The changeover

from working system to standby system under emergency and shock dosing is done

manually.


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2.0 CONTROL PHILOSOPHY FORC. W. CHLORINATION AND ABSORPTION SYSTEM.

This write-up covers the Electrical Control details available in the control scheme and is prepared in

accordance to the P & I Diagram 2384-CW-C02-001

The Control circuit has been designed to operate the Chlorination Plant in a smooth, automatic and

safe manner to a minimum of operator interference. The Electrical Controls are achieved with the help

of a number of pressure and temperature switches and instruments spread around the Chlorination

area. The Electrical System consists of the following:

1 The Motor Control Center (by client)

2 The Chlorination Plant Local Control and Annunciation Panel (LCP).

POWER SUPPLY SCHEME:

The MCC is to provide 3 phase power to all the 3 phase electrical loads viz. the Booster

pump, blower, caustic pumps, Evaporator heaters and single phase power, to the chlorination

plant. The Controls for these loads will be from the Chlorination Plant Local Control Panel. AllSingle Phase load including actuators for Motorized valves / Damper will be fed from Local

control panel.

Unidirectional drives (Contactor Operated)

a The unidirectional drives is to be operated normally from the LCP.

b Local Push Button Station consists of stop push button. The stop push button will be provided

with a lock. Under locked position, the drive start operation is inhibited.


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c Remote control commands i.e. start / stop is to be generated from LCP system and is to be

wired to MCC through interposing relays. These relays are to be located in the MCC.

d Remote control commands are generated by manual operation of start-stop push button

station mounted on LCP.

e Necessary electrical protection is to be realized at MCC, whereas process interlocks and

protections are realized on PLC. Thus, drive can be operated provided all process and

electrical interlock conditions are fulfilled.

The following signal exchange is take place between MCC & LCP

Drive start / stop command (Potential free)

Drive Trip feedback (Potential free)

Drive status feedback (Potential free).

LOCAL CONTROL & ANNUNCIATION PANEL (LCP):

A LCP is provided for C.W. Chlorination and absorption System. In reference to the P & I drawing of

Chlorination Plant the Controls and operation available are as described below:

Two number of three -phase 415 volts 50 Hz power is to be provided from MCC to redundant UPS,

which in turn gives single phase 230 VAC supply to the control panel. Control supply for the PLC logic

is 24 VDC. LCP is provided with two number SMPS (230/ 24 VDC) for this purpose, with redundant

scheme.


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Controls & Annunciation on Local Control & Annunciation Panel for Chorine

feed system:

CW Chlorination and Absorption System:

The differential pressure switch 00CP200 mounted across the basket strainer and set at 1MWC is

used to annunciate the increase of pressure drop across the basket strainer. The standby strainer

is put in to operation and in service basket strainer is taken in to maintenance.

The pressure switch 00CP201 & 00CP202 are installed at booster pump discharge header and

set at 3.5 kg/cm decreasing & 4.5 kg/cm increasing respectively. They are used to provide low

header pressure and high header pressure at the booster pump discharge. Under consistent low

header pressure for a longer period the LCP would switch off one of the booster pump and switch

on the standby pumps. This would continue till the low header pressure switch returns back to

normal.

The pressure switch 00CP203 are installed at liquid chlorine header and is set at 2.5 kg/cm

decreasing and provides advance alarm for the in service chlorine tonner getting emptied.

The pressure switch 00CP204 (Set Pressure - 15 kg/cm) at the liquid chlorine header will be

used to give High header pressure Audio-Visual Annunciation. This is advance intimation for

rupture disk to be burst, if immediate corrective action is not taken.

The pressure switches 00CP205, 00CP206 & 00CP207 (Set Pressure - 2.5 kg/cm increasing) at

the outlet of Rupture disc on liquid line (individual header and common header) are used to give

Audio-Visual Annunciation to indicate that the Rupture Disc is busted. The pressure switch 00CP208 & 00CP209 (Set Pressure - 1.0 kg/cm decreasing) at each of the

liquid chlorine tonner headers will be used to give Low tonner pressure Audio-Visual

Annunciation. This will also activate tonner auto switchover.

The pressure switches 01CP200 to 04CP200 (Set Pressure 0.8 kg/cm decreasing) is used for

tripping individual water booster pumps if the suction pressure goes low below the set point.

The pressure switch 01CP201 to 04CP201 at the PRV downstream is used to give Audio-Visual

Annunciation to indicate that the PRV downstream pressure is high. This is set at approximately 4

kg/cm.

The differential pressure switch 01CP202 to 04CP202 at each set of Chlorine gas filters is used to

give Audio-Visual Annunciation to indicate that the Gas filters at the outlet of the evaporator are in

choked condition. The switch is set at 0.8 kg/cm increasing.


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The pressure switch 01CP203 to 04CP203 at the Evaporator gas outlet of each Evaporator is

used to give an Audio-Visual Annunciation to indicate excessive gas pressure built-up in the

Evaporator. This is set at 15 kg/cm. It is advance intimation for the rupturing of disc and

activation of pressure relief valve mounted at the outlet of evaporators.

The pressure switch 01CP204 to 04CP204 at each gas line rupture disk is used to give Audio-

Visual Annunciation to indicate that the Rupture Disc is blown. The switch is set at 2.5 kg/cm

increasing.

The pressure switch 01CP205 to 04CP205 mounted on the chlorinator are used to provide

annunciation of high vacuum generation or non availability of chlorine gas with ejector working.

This is set at approximately -0.6 Kg/cm.

The pressure switch 01CP206 to 04CP206 mounted on the chlorinator are used to provide

annunciation of low vacuum generation or problem in working of the ejector or not enough water

passing through the ejector. This is set at approximately -0.2 kg/cm. The same can be confirmed

by checking the flow meter installed in series with the ejector.


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Controls available from Vaporizer are as below:

The water level control of the bath is achieved by means of a level switch 01CL202 to

04CL202 integral with individual vaporizer. The inherent self-differential of this switch

controls a direct acting solenoid valve to make-up the evaporation losses of the water in the

bath. Another set of level switches 01CL201 to 04CL201 is used to provide alarm decrease

in water level of the bath, and level switch 01CL200 to 04CL200 is used to trip the heater of

respective evaporator to protect it from damage due to dry operation.

The water temperature is controlled by means of a temperature controller. The water

temperature is displayed on the front by means of a temperature indicator. The temperatureis controlled by means of control set point from temperature controller. An immersion type

water heater is provided to maintain the set temperature. The controller maintains the set

temperature within a very small differential. 01CT202 to 04CT202 temperature switches are

used as high set point and is available to annunciate excessively high water temperature, and

also to trip the heater. The same is set at approximately at 75 C. 01CT201 to 04CT201

temperature switches are used for maintaining the water temperature in the water bath.

Energisation of the switch will cut off the heater and dropping of the switch will energize the

heater. The same is set at approximately at 65 C. 01CT200 to 04CT200 temperature

switches are used for the energisation of fail safe solenoid PRDV mounted at the outlet of

chlorine gas filter. The energisation of this switch confirms that the chlorine gas will not get

reliquified as it is important for the MOC of the gas filters and equipments mounted at the

outlet of the evaporator. The same is set at approximately at 55 C


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C W CHLORINATION BOOSTER PUMPS OPERATION SCHEME FROM LOCAL

CONTROL & ANNUNCIATION PANEL:

Four Nos. of Booster pumps are operated for four stream of Evaporator and Chlorinator. At a time

there are only three streams are working & 1 will be in standby mode. Hence, a pump standby

selector switch is provided which will prevent the entire four pumps operating at a time. This is the

same selector switch which is used as pump selector switch in manual mode. Common START and

STOP push buttons are provided for starting and stopping the pumps under manual operation.

Emergency STOP will be provided locally near the pump.

The pressure switches 01CP200 to 04CP200 (Set Pressure 0.8 kg/cm decreasing) is used for

tripping respective water booster pumps if the suction pressure goes low below the set point.

The pressure switch 00CP201 & 00CP202 are installed at booster pump discharge header and

set at 3.5 kg/cm decreasing & 4.5 kg/cm increasing respectively. They are used to provide low

header pressure and high header pressure at the booster pump discharge. Under consistent low

header pressure for a longer period the LCP would switch off one of the booster pump and switch

on the standby pumps. This would continue till the low header pressure switch returns back to

normal.

With the start of the chlorination system the controller checks for the selected standby pump and start

the booster pump one after another. If one of booster pump trip feedback is available or the suction

pressure switch of the pump is low, the next pump is started skipping the tripped pump. At any point

of time there would be at least three pumps in operation to provide the required pressure for operation

of the system. This is also checked by the switches 00CP201 & 00CP202 mounted at the header of

the booster pump discharge. Under any circumstance if either of the three working pump stops or

trips for any condition the standby pump is put in to operation. This is in normal condition. The second

condition is the shock dosing condition in which all the pumps are to be put in to operation to provide

the required pressure for operation all the four system. The switching of the fourth pumps is automatic

depending upon the time and the duration set in the program. After the set duration final setting ofwhich would be done at site the standby pump should go off and stay in standby mode.


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THE CHLORINE LEAK DETECTION SYSTEM:

Thirty Nos (30) Chlorine gas leak sensors, with 7 multipoint monitor, 1620B, are provided, to cover

the entire chlorination plant for leak detection. These are as below:

Sr. No. Location Monitor sensor

01 DUCTING OF CONNECTED TONNERS IN STREAM-1 1 6

02 DUCTING OF CONNECTED TONNERS IN STREAM-2 1 6

03 DUCTING OF STORAGE TONNERS (ROW#1) 1 4




07 CHLORINATOR/EVAPORATOR ROOM 1

08 CHLORINE PIPING IN TONNER ROOM.1

1

TOTAL 7 30

The monitor will give Audio-visual Annunciation of indication of the leak on Local control panel. An

Electronic Hooter is provided on gas detector monitor along with acknowledge and reset button.


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THE CHLORINE LEAK ABSORPTION SYSTEM:

This system consists of the followings:

1. 2 Nos (1W + 1S) Caustic re-circulation pump

2. 2 Nos (1W + 1S) Chlorine Air Mix Blower

3. Caustic Storage Tank with tower.

The Absorption System starts automatically; if any of the 6 sensors i.e. Detector no 1 to Detector no.6

as mentioned above senses the gas leak. The Control Philosophy is as explained below:

1. A Caustic re-circulation pump selector switch is provided in the control Panel for selecting the

working or standby pump. When a gas leak is sensed 3 ppm and above by any of thesensors, the caustic pump will immediately start to re-circulate the caustic. In case the

selected pump trips when in operation the standby pump will automatically start. Pump ON,

OFF & TRIP indication will be provided in the Local Control Panel. An Absorption system

manual START and STOP push buttons will be provided.

2. Damper is provided at discharge of each Blower, which will be operated when the caustic

pump starts, or stops. When the caustic pump starts the Damper of the selected blower will

also open. Damper open and close indication will be provided on the control panel. A blower

selector switch is provided in the damper circuit. After the dampers are open only then the

blower will be permitted to start.

In case the damper does not open within 15 seconds of caustic pump starting, the damper

close command will be released and the stand-by damper will open.

3. As soon as damper opens, corresponding blower gets started and stops immediately after the

damper starts closing. In case the selected blower does not start within 15 seconds, the

damper will close and the damper of the standby blower will open. The stand-by blower will

then start.

Separate blower ON and OFF push buttons will not be provided on the control panel for

safety reasons. It will only START and STOP with damper. ON and OFF indicating


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lamps will be provided for each blower. However, Absorption System Manual START

push button will be provided on Local Control Panel to manually START the Absorption

System. Drive tripped annunciation will be provided.

4. For stopping the Absorption system, the operator has to manually do so, after verifying that

the chlorine leak detector are now at normal, confirm the leakage has stopped, reset the gas

detector and only then STOP the Absorption System by depressing STOP push button.

Caustic solution tank is provided with a level switch for performing the following function:

LOW LEVEL SWITCH: The switch 00CL200 is provided to give audiovisual annunciation of low

level in caustic solution tank on Local control panel. It also will trip the caustic pump and avoids

dry running of the caustic pump. It is also interlocked to the agitator, to trip in case of very lowcaustic level.

One set of potential-free changeover contacts will be provided from the LCP for switching OFF the

related ventilation fans in case a chlorine leak is detected. For each ventilation fan, a separate

changeover contact will be provided.

Documents

Control Potable Water