Boiler Flame Scanner Retrofitting at Front Fired ABL make Boiler – 60MW Unit

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Purpose:

1. To protect the boiler from explosion

2. To provide oil support from remote for furnace stability

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Protection of Boiler

Oil Burner Management applications at TGS

Flame scanner will sense the flame at each tier.

Generate a status contact according to the flame condition.

Status contact is monitored at DCS.

In flame adverse condition at furnace, DCS logic will prohibit oil ingress at furnace.

Status contacts actuating limits can be modified.

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What are the basic Functions?

Prevent firing of oil burners unless a satisfactory Flame condition is achieved.

Prohibit start-up of oil burners unless certain permissive interlocks have been completed.

Monitor and control the actual Flame condition and generate annunciation for next action.

Execute a MFR upon certain adverse unit operating conditions.

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Flame Scanner:

The micro processor based flame sensing system is primarily

responsible for sensing the flame by its characteristic fluctuations. The

energy level or intensity of the flame is sensed by the brightness of the

flame and the frequency is sensed by the flickering of the flame.

Flame Scanner

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SCANNER

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Real Life Photo

The scanner head is installed on the air register of the wind box assembly at

the pip hole designated as scanner pipe, at the bottom side.

One Ball flange 2” to 1” (Swivel joint) is installed before the insulator for

proper alignment.

Cooling air line from Cooling air fan (Dual redundant- AC& DC fans)

The respective control & communication cables are routed to the UCR-DCS

panel.

Installation

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Cooling air line from

Cooling air fan (Dual

redundant- AC& DC fans)

Flame Scanner

Scanner pipe

Scanner

Communication

cable Terminal

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The output signal from transmitter is received in a dedicated PC and

processed with a Flame scanner software.

The user will see the condition of the 15 no flames on the monitor. Each

flame can be further checked with all available condition- frequency & intensity.

The histogram allows the user to trend in real time.

Scanner Signal at dedicated PC Monitor

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Single Module Screen

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Solenoid Oil Valve

Valve Type: Globe type solenoid operated, pneumatic actuator, Open &

Close limit switches, air regulator.

Valve make: Continental Valve

Location: The solenoid operated pneumatic valves are installed at each oil

burner, after the tier isolating manual operated oil valve.

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Continental valveSolenoid valveAir regulator

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Modified Oil line Diagram

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Indication & Annunciation at Boiler Panel:

A separate Control panel with

LED indications & annunciation

facia with hooter is installed at

UCR.

When the condition of any flame

is ‘Good’ the LED will glow. When

the flame condition is dull or ’Bad

Flame’ the LED will put off.

‘Poor flame’ condition is the

another condition. Scanner O/p

4-20ma is programmed such a

way that it will sense the “poor

Flame’ condition. In the ‘Poor

Flame’ condition the

annunciation will appear.

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Operation Control & Logics

Step1:

The purging air line valve will be kept in shut condition. The atomizing air

line valve will be kept in open condition. The gun system will be in retracted

condition.

Shut off valve operation will be remained same, i.e. to be opened after

signal from UCR & master reset at B/F.

Orifice valve will be in bypass condition

Step2:

The oil valve can be opened from DCS or through indicator type Push button

on the back panel.

Valve Open-Close Indication will be available at UCR.

The valve can be closed from DCS only.

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Operation Control & Logics

After opening of solenoid operated oil valve;

The operator will insert the retracted gun assembly as soon as possible and

put the orifice in line.

After closing of solenoid operated oil valve;

The operator will extract the retracted gun assembly.

Purge the oil line by opening the purging valve & closing the main oil line valve

for some time

Close the purging valve, open the oil line valve

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DC MCB

AC MCB

Scanner

module

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Flow-Chart of Control & Logics

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Scanner Cooling System

As the flame sensing lens as well as the scanner

is installed at heat zone, a continuous cooling air

is passed through it. For this purpose a

dedicated cooling system is installed at burner

front.

The system comprises two separate blower fans,

one with AC drive & the other with DC drive. The

suction of the fans is from atmosphere with

adequate air filter.

In normal condition, the AC fan will run. In case of failure of AC system,

automatic change over to DC system will occur with annunciation at UCR .

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Thank you very much for patient hearing

Q&A

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