A PRESENTATION ON BOILER INSTRUMENTATION & CONTROL

SUBMITED TO: SUBMITTED BY:

Mr. P.K.GANGULY Er.NAVEEN KUMAR

(Seminar Cordinator) 10ESEEE055

OverviewIntroduction of boilerClassification of boilerBoiler instrumentationBoiler controlconclusion

INTRODUCTIONA boiler is a closed vessel in which water or other

fluid is heated. The heated or vaporized fluid exits the boiler for use in various processes or heating applications.

Instrumentation and controls in a boiler plant encompass an enormous range of equipment from simple industrial plant to the complex in the large utility station.

The boiler control system is the means by which the balance of energy & mass into and out of the boiler are achieved. Inputs are fuel, combustion air, atomizing air or steam &feed water. Of these, fuel is the major energy input. Combustion air is the major mass input. Outputs are steam, flue gas, blow down, radiation & soot blowing.

Classification of boilerBoiler are classified on following configurationFire tube boilerWater tube boiler

Fire tube boilerHere, water partially fills a boiler barrel with a small volume left above to accommodate the steam (steam space).

This is the type of boiler used in nearly all steam locomotives. The heat source is inside a furnace or firebox that has to be kept permanently surrounded by the water in order to maintain the temperature of the heating surface just below boiling point.

Diagram of a fire-tube boiler

Water tube boiler In this type, the water tubes are arranged inside

a furnace in a number of possible configurations:

often the water tubes connect large drums, the lower ones containing water and the upper ones, steam and water; in other cases, such as a mono tube boiler, water is circulated by a pump through a succession of coils.

Diagram of a water-tube boiler

- High temperature resistant optical system consists of quartz and corundum, which can be normally operated in a certain amount of purging air.

- Screen menu setting, remote control in central control room, for forward and retract movement of camera.

- Horizontal mounting and large field angle probe

- System is equipped with automatic forward and backward protection device, which can automatically withdraw from furnace when no pressure in cooling air.

Furnace TV :

FLOW METERThe flow meter is designed to measure flow rate

of a fluid.Measurement is based on Faraday’s law of

induction, according to which a voltage is induced in an electrically conductive body which passes through a magnetic field.

The following expression is applicable to the voltage.

U = K * B * V * DWhere:

U = induced voltageK = an instrument constantB = magnetic field strengthV = mean velocityD = pipe diameter

Boiler control

+ I N P U T O U T P U T

F I R I N G R A T E

D E M A N D

F U E L D E M A N D

A I R D E M A N D

F E E D W A T E R C O N T R O L

S T E A M T E M P E R A T U R E C O N T R O L

BOILER

BLOCK DIAGRAM DESCRIPTIONThe block diagram of boiler control is shown in

above figure the output from the boiler i.e, the steam outputs and the level of water is given to transmitters.

The major loops in boiler control are 1) Combustion control

2) Feed water control

COMBUSTION CONTROLA combustion control system is broken down into (a) fuel control and

(b) combustion air control subsystems.

HARDWARES USED IN COMBUSTION CONTROL

ON/OFF controls

Positioning systems

Metering control system

FEED WATER CONTROL

Feed water control is the regulation of water to the boiler drum. It provide a mass accounting system for steam leading and feed water entering the boiler.

Proper boiler operation requires that the level of water in the steam drum should be maintained within certain band.

A decrease in this level may uncover boiler tubes, allowing them to become overheated.

Levelling Vessel Level Control by-

Feed Water Control

BCP

CV to 1st stage DSH water

Drain CVs to

Condensor

From Separator-B

BCP Discharge

CV to Eco. I/L

Levelling Vessel

From Separator-A

Drain CVs to

OAC/Waste

ADVANTAGESMultiple element feedwater control can help:

i. Faster response of systems.ii. More accurate control.iii. Maximum system stability.

Metering control system maintains combustion efficiency over wide load changes and over long period of time.

DISADVANTAGESBoilers require quick responding controls.Level of the water in the boiler must be kept

above 50% of height.

CONCLUSIONThe various goals of boiler control includes:

1. To minimize excess air2. To minimize blow down3. To minimize steam pressure4. To measure efficiency

Thank YOU & ANY QUERY ???