BOILERS INSPECTION.ppt

7/21/2019 BOILERS INSPECTION.ppt

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BOILERS


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SCOPE:

This procedure is intended to give

guidance to the plant inspector tocheck, evaluate, and asses thecondition of the water tubes boilercomponents and recommend any

necessary repair.


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Function

>> The purpose of the utility boilers is to produce superheated steam

for use in the process units. The primary source of boiler feed water is

the clean condensate returned from steam users throughout the

complex. The makeup water is from the process water after it has beenDemineralized. Both the condensate and the Demineralized water enter

the deaerators D-6!"#B before reaching the boilers. The maximum

continuous rating of the boiler is $%! Ton#h. The normal operating

temperature and pressure are & ' and &&( )pag respecti*ely.


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Forced Draft Fan : " fan supplying air underpressure to the fuel burning e,uipment.


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Induced Draft Fan : " fan exhausting hot gases frothe heat absorbing e,uipment.


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"n enclosed space pro*ided for the combustion of fuel.

Furnace/Fire

Box


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" drum at the bottom of the boiler which is connected tothe steam drum by the *ertical bank tubes. The drum is

also connected to the furnace wall tubes. +nside the

drum an intermittent blowdown pipe is fixed along the

drum bottom with 6 mm holes to remo*e any deposits

from the drum.

Mud Drum


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" drum at the top of the boiler which is connected to themud drum by the *ertical bank tubes. The drum is also

connected to the furnace wall tubes. The drum contains

che*ron dryers that are installed at the top to remo*e the

moisture.

Steam Drum:


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etal screen with small openings to retain solids andparticles in fuel media which could detrimentally affect

the operation of the burners.

Strainer


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The superheater is a con*ection type and it consists of threeset of bank tubes secured to two headers by weld /oints. +t is

installed between the screen tube zone. The saturated steam

from the steam drum is superheated through the three pass

superheater.

Superheater


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" chamber below the grate or surrounding a burner

through which air under pressure is supplied forcombustion of the fuel. 0ne type called a burner wind box

which is a chamber around a burner in which an air

pressure is maintained to ensure proper distribution and

discharge of combustion air.

Wind box


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SILENCERS

Two silencers to be checked in the boiler, one is the start-up

Vent Silencer, and the second is the SV Silencer for thenormal operation.


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Stack


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REFERENCES

API, Guide for Inspection of ReneryEquipment, Chapter VIII- Direct-FireBoilers and u!iliary Equipment,"econd Edition #$%&'API 510, (ressure Vessel Inspection

Code, )aintenance, Inspection, andlteration, "e*enth Edition #$$+'

ASME, Boiler and (ressure Vessel Code,"ection I, (oer Boilers, Edition #$$+'

ASME, Boiler and (ressure Vessel Code,"ection VIII, Recommended GuidelinesFor the Care of (oer Boilers,

Edition #$$+'


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BOILER INSPECTION

>> "ccording to "12 standard section + and 3+++

Boiler has to be inspected annually. "4+ 'hapter 3+++

does not specify any inspection inter*al. 5rom "742Texperience it has been decided that the boiler shall be

down for inspection e*ery two years. There are two

types of inspection during operation and during outage

inspection.


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DURING OPERATION INSPECTION

"" The inspection during operation should bedone to ensure that the outside surface and

parts are in good opera table condition. #t also toensure no leaks, hot spots, corrosion, norsettlement are exist. The external inspectionmay be done during the operation of the boiler,however, the main foundation and supports of

the $re box shall be done during the boileroutage.


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FOUNDATIONS

>>The important of foundation can not be

o*eremphasized. "ny o*erlook of the foundation

deterioration might lead to e,uipment bearing

failures refractory failures steam leaks

and.....etc. Tapping the concrete with a hammer

will re*eal deterioration or unsound conditions.5oundation should be checked for8

A)-1ettlement which is caused by water wash or high

*ibration. 1ettlement of the foundation can be detected by

cracks in the concrete brick walls and ad/acent flooring.1ur*eyor9s le*el or transit or transparent hose water

le*el can be used to check the settlement. Boiler

manufacturer often put le*el marks on drums or other parts

that can be used to check settlement.


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B)- 1palling usually caused by excessi*e heat

mechanical shock the corrosion of reinforcing

steel.

C)- 'racks in concrete which may be caused by

excessi*e heat poor design material

mechanical shock or une,ual settlement.

D)- 1oundness of the anchor bolts.


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LADDERS, STAIRWAYS,

PLATFORMS & WALKWAYS

"" The ladders, stairways, platforms, andwalkways should be checked carefully byvisual inspection aided with lighthammering and scraping the oxide scalesand other corrosion products. They should

be checked for%

&racks.!roken parts.

Tightness of bolts.Wear of ladder rungs and stair treads.The condition of the platforms 'ooring.&orrosion beneath painted surfaces which

will beindicated by rust stain or blistering.


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PIPING

The piping and their connections are items may be

affected if any *ibration settlement earth,uakes and fire

damages occur to the boiler. They should be checked for8

:;igh *ibration.:


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INSULATION

The insulation and cladding of the boiler components is

considered as one of the ma/or items that it should be in good

condition due to the fact that any defect or loss of insulation

will cause loss of heat and may sub/ect personnel to heat

burns. The insulation should be checked for8

:;ot spots may indicate hidden defects in the insulated

parts.

:=n-secured parts of cladding.:1ign of leaks may indicate a hidden problem.:Deterioration and general defects.


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AUXILLARY EUIPMENT

"uxiliary e,uipment such as gauges connections

sight glasses and safety *al*es may be inspected*isually for8

:=ndue *ibration.

:'orrosion and breakage.

eneral deterioration.


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DURING OUTAGE INSPECTION

#nspection will be carried out when theboiler is out of service either in plannedshutdown or an emergency shutdown.

The emergency shutdown usually in short

period of time, therefore, completeinspection could be di(cult. )owever, itis considered a good chance for checkingthe critical areas and*or the areas with

previous problems. !efore startinginternal inspection, the results of therecent external inspection and theprevious internal inspection should beused as a guide for the current internalinspection, e. g. a hot spot on the casing


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+ preliminary inspection of the inside ofthe boiler shall be carried out before theboiler is cleaned. The location, amount,physical appearance, and analysis of mudand sludge or scale deposited on theinside of tubes and drums will provideinformation relative to the eectiveness ofthe feed water treatment, blowdown

operation and method of cleaningneeded. The preliminary inspection mayalso be helpful in determining which partof tubes or drums reuire close

inspection.

CONTINUATION!


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FIRE BOX

The fire box ?furnace@ is the main and ma/or component of

the boiler. The fire box is constructed of water wall tubes

backed up by firebricks ? refractory@ block insulation and

steel plate casing. The fire box should be inspected

internally by checking the following items *isually and#orby using any of the 7DT methods.

TUBES:

"ll tubes should be checked for 8

:Blistering and Bulging.:'racks.


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:Bowing and 1agging.:'orrosion.:Deposit that will effect the heat transfer.:etal loss may be done by checking the wall thickness

of the tubes using =ltrasonic as per A.$.:1oot and dirt shall be remo*ed and area below it should

be inspected.

verheating.

Tube may be x-rayed to check the internaldeposit andwall thinning.


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"ll the tubes should be inspected for signs of o*erheating

corrosion and erosion. =sually o*erheating is caused by

deposits or excessi*e scale on the water side of the tube. The

nearest tubes to the burners are susceptible to o*erheating

and should be closely examined for bulging blistering

,uench cracking sagging and bowing. Blistering and bulging

is easily accomplished by shining a flashlight parallel to the

length of the tubes so that bulges or blisters will cause

shadows.


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The locations of the thickness measurements shall be

identified so next shutdown the readings will be taken in

the same locations for comparison.


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REFRACTORY

The refractory should be inspected for8

:'racks.:2rosion.:elting.:Bulging.:5all down.

&racks in the refractory are common and are to

be expected but if the cracks is severe, thenrepairs should be made. #f the erosion andmelting are present, then the refractory has tobe carefully evaluated before putting the boiler

back into service. /etal shell and insulationbehind the refractor will become overheated if


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BURNERS

"ll burners should be checked for8'orrosion.

2rosion of tips.

Burning and elting.

1palling.

'racks.eneral deterioration.


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STEAM DRUM

The drum should be inspected internally for8

:1eam welds cracks.:'orrosion.:4itting.:roo*ing.:1cale deposits and sludge accumulation in shell and tubes.:Tightness.

:Deterioration.:1oundness.:1tructural stability.:etal loss


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MUD DRUM

The mud drum ?water drum@ should be checked for8

:'orrosion.:4itting.

:roo*ing.:'racking.:1cale deposits and accumulation of sludge in shell and tubes.

etal loss as


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Special attention should be paid to all seamwelds and should be examined for cracks and

corrosion. &orrosion ad0acent to the seam weldis more serious than a similar amount ofcorrosion in the solid plate away from theseams. &racks along the seams is likely to occurwhen the material is highly stressed.


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SUPER"EATER

The superheater should be checked for8

:'orrosion and paint defects.:1igns of leaks.:'racks at weld /oints.:all loss of headers and tubes thickness check to be taken

in fixed points as per:elting burning and#or heat damage to the internals.

:1ign of insulation and refractory deterioration at thewalls.

:eneral damage or breakage.


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ECONOMI#ER

The economizer should be checked for8

:'orrosion and paint failure.

:'racking at weld /oints.:1igns of leaks.:all loss of header and tubes thickness check to be taken in

fixed points.:Damage to the structural and *ane plates.:Tightness of bolts and clips of header and tubes.:1ecurity and cleanness of *ents.


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BANK TUBES C"ANGER

The bank tubes chamber should be checked for8

:'orrosion and paint failure.:'racking at weld /oints.

:1igns of leaks.

:all loss as per:Damage to the structural and *ane plates.

:Tightness of bolts and clips of header and tubes.


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SIDE WALL TUBES

The side wall tubes should be checked for8

:'orrosion and paint failure.:'racking at weld /oints.:1igns of leaks.:all loss


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WIND BOX AND F$D$ FAN

They should be checked for8

:'orrosion and paint failure.:2rosion due to ash particles.

:Thinning and holes in the fan blades.

:eneral deterioration.:Damage of the lou*ers near the burners.

"ny damage deterioration or paint failure on theburners *isible parts


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STA

The stack should be checked for8

:Cefractory damage:'orrosion on the stack metal parts.:2rosion.:0*erheating.

:2xternal 4aint damage.


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STRAINERS

Two strainers for the gas and the diesel fuel to be

checked in the boiler shutdown. They are located at the

top platform in the inlet lines to the boiler. They should

be checked for8

:Breakage in the screen.:;ea*y deposit.

:'orrosion.:5oreign materials.

Deterioration in the screen or the body


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%AL%ES

During the boiler shutdown there are two *al*es to be

checked one is the boiler feed water non-retaining *al*e

and the other is the superheater non-retaining *al*e. They

should be checked for8

:2rosion.:'racking in the seat and seat ring.

:'orrosion.:eneral deterioration.


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SILENCERS

Two silencers to be checked in the boiler one is the start-up

3ent 1ilencer and the second is the 413 1ilencer for the

normal operation. The smaller one is for the start-up. They

should be checked for8

:'orrosion internally or externally.:'racking in the weld /oints or the body.:Deterioration in the internals.:Damage to the connecting fittings.:'orrosion or deterioration of the inlet piping.


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LUBE OIL COOLER

The cooler usually opened during the scheduled boiler

shutdown for cleaning and inspection. +t should be checked

for8

:Tube plugging.:'orrosion.

:2rosion in the channel co*ers or heads.:'racks or damage.

+f leak is suspected the cooler should be hydrotested from theshell side to $.% times the design pressure of the shell and

obser*e any leaks through the tubes this test should be done

when all co*ers and heads are remo*ed.


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T"ICKNESS MEASUREMENTS

The thickness measurements shall be taken at se*erallocations ?"ttachment +++@ at the boiler as follows8

FIRE BOX:

"ll four sides of the wall tubes shall be co*ered by the

thickness check at fixed locations. The thickness shall be

checked at $.% . from the floor on the following selected

tubes8

NORTH WALL: $ tubes first & from east & tubesat the middle ?tube no. %( to 6$@ and the last & tubes at the

west side

?tube no. $$6 to$$E).


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CONTINUATION!

SOUTH WALL (SCREEN & BAFFLE TUBES): ! screen

tubes at the middle section ?tube no. A to E@. E baffle tubes

first three at east side ! at the middle ?tube no. %$ to %!@ and

the last ! tubes at west side ?tubes $ to $&@.

WEST WALL (BURNER SIDE): & tubes tubes at the

center ?tube no. ( and E@ of both north and south sections.

EAST WALL (MAN-WAY SIDE): E tubes first ! tubes at7orth corner and ! tubes ?tubes no. to &@ at the center and

the last ! tubes at south corner ?tubes n. &% to &A@.


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STEAM DRUM:

The thickness shall be checked on the steam drum at the

following locations8

HEADS: Both heads shall be checked at !6E

and $ 09clock positions.

SHELL: The shell shall be checked at the top

and the bottom sections and thethickness shall be checked Fat three

locations east middle and west sides.

The top section shall be checked from

outside.


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MUD DRUM:

The thickness shall checked on the mud drum at the following

locations8

HEADS: Both heads shall be checked at !6E

and $ 09clock positions.

SHELL: The shell shall be checked at the top andbottom sections in three locations east

middle and west sides.


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CONTINUATION!

SUPERHEATER:

The thickness shall be checked on the superheater at the


TOP CHAMBER:

TUBES:$ tube in each of the east middle and

west banks tube no. $ counting from

east of each bank.

HEADER:! locations east middle and west.


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BOTTOM CHAMBER:

TUBES: $ tube in each of the east middle

and west banks tube no. $counting from east of each bank.

HEADER: ! locations east middle and

west.


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ECONOMIZER:

The thickness shall be checked on the economizer at the


TOP CHAMBER:

TUBES: $ tube in each of the east middle

and west sides ?tubes no. $ $A and

! counting from east@ of both southand north ends.


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HEADER: 3 locations east, middle and west side plus

one point at the bottom side of each branch.

BOTTOM CHAMBER:

TOP SECTION TUBES: $ tube in each of theeast middle and west sides ?tubes no. $ and !

counting from east@ of the north end.

BOTTOM SECTION TUBES: $ tube in each ofthe east middle and west sides ?tubes no. $ and

! counting from east@ of the south end.

CONTINUATION!


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BANK TUBES CHAMBER:

The thickness shall be checked on $ tube in each of the north

middle and south sides ?tubes no. $ $A and ! counting from

north@ at $.% from the floor.

SIDE WALL TUBES: "ll 6 tube shall be

checked one point each.

CONTINUATION!

OS C S


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"YDROSTATIC TEST

"" +fter completing the inspection, the boilershall be hydrostaticly tested to a pressure eualto 1.2 times the maximum allowable workingpressure 3/+W4, thus the testing pressure shall

be 5567 8a9. The pressure shall be increasedgradually, max. :;; 8a9 per minute and shallbe held for at least :; minutes. Then the testpressure shall be reduced to the /+W, 6

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BOILERS INSPECTION.ppt