7/29/2019 Boiler Inspecting

1/2

ALL RIGHTS RESERVED. Do not duplicate this document by any method without prior written permission from Chemical Solution,

Inc.

Chemical Solution, Inc. Technical Data Shee

INSPECTING BOILERS AND RELATED EQUIPMENT

Boiler Water Treatment should consider the control of

corrosion, deposition and carryover. The water treater andboiler operator will monitor various parameters duringonline operation to help control and assess treatmentperformance. The physical inspection of boilers andrelated components is a critical part of monitoring boilertreatment performance. A thorough boiler inspectionprovides:

Visual verification of boiler system health or illness.

Early identification or warning to the water treater andoperator of problems or impending troubles.

Written confirmation of the boilers condition in additionto the Boiler Inspectors report.

Visual confirmation of the physical design and layout ofequipment components.

Equipment Needed

The following is a list of equipment that should be availableto conduct a thorough and safe boiler inspection:

Coveralls (ideally with hood) - some plants may requirefire retardant clothing.Safety glasses- usually required.Safety hat- this may be optional.Safety shoes- this may be optional.Gloves- boiler surfaces may be hot.Magnet- use to check for presence of magnetite.

Flash light should provide a focused, bright light and bebig enough so that it cant accidentally fall inside a tube(water tube boiler).Scraping device- knife or screw driver (with wrist strap) toremove and collect sample.Deposit sample bags- inert, watertight container is ideal.Camera - good documentation tool, if allowed. Getpermission ahead of time.Inspection Report Form or Dictaphone document theinspection on a prepared form or verbally using adictaphone (see Boiler Inspection Forms 1 & 2).Combination lock or Lock & Key - some plants requireall persons entering the boiler to provide your own pad lock

as part of a lockout and tagout procedure.Inspection probes & Video camera - in some specialcases a boroscope, fiberscope, turner gage, etc. may bedesirable. Usually, these devices can be rented and willcost $1000 - $2000 per rental. These devices are usedwhen critical problems exist in areas not readily visable.

Pre-inspection Recommendations

Preparation:

Prior to the inspection it is helpful to review the boiledrawings (internals, drum and fireside layout) to familiarizyourself with important design details such as: equipmenlocation, areas of high heat transfer (likely locations foproblems), and flow patterns for the various flue gas, wateand steam circuits. Occasionally, you can find whermodifications or installation errors have been made whicwill help explain visual or operational anomaliesMoreover, knowing the boiler layout will help better identifobservations in terms that plant personnel not present tvisually inspect the boiler can understand and use focomparison to past & future inspections. Finally, ask if th

insurance inspector and/or plant personnel has alreadinspected the boiler - speak with this person(s) or reviethe written observations.

If you have limited knowledge of the equipments desigand operating history, your ability to provide a thorougevaluation is significantly diminished.

Safety:

Most plants have some type of formalized safety programwith procedure checks (i.e., lockout and tagout & confinespace entry procedures) and these should be understooin advance follow these safety procedures. If formalized safety program is not in place, use the followin

guidelines:1.Make sure someone in a responsible position from thplant, especially boiler operators, know you are enterinthe equipment.

2.Have someone dedicated to watching you. This spotteshould be stationed within visual contact at all times.

3.Make sure that the non-return valve and aninterconnected piping (e.g., blowdown, feedwater, anchemical feed or nitrogen purge lines) be valved shut odisconnected, tagged and preferably locked (ideally wityour lock).

4.Do not allow use of AC electric devices in the boilewithout appropriate GFI protection.

5.Check to ensure the surfaces are sufficiently cool.

6.Do not enter a confined space unless proper precautionare taken - air quality check, proper ventilation provided. Isome cases a safety harness may be required.

(continued on other side

7/29/2019 Boiler Inspecting

2/2

Inspection Techniques

Watertube Boilers

Steam Drum:

The steam drum is a convenient point of access into theboiler and will provide key information. Check thefollowing:

Water Level - the water level can usually be detected onthe side of the steam drum as a definitive marking. Note

the height and any indication of height variation (how eventhe line is across the drum). Multiple lines or variation inthe water level is a symptom of foaming or poor levelcontrol.

Check for deposits and corrosion above and below thewaterline. Check beneath the tubercle to determine if thepit is black indicating it is still active. Pitting is typicallycaused by oxygen.

Check and note the location and orientation of all internals(headers, laterals, separation equipment, etc.). Observethe header orifices for orientation, size, number, and signsof wear. Improper installation or wear can impacttreatment performance.

Physically check to ensure all internals are secure. Note

any loose or lost bolts. Loose or failed internals willgreatly impact boiler performance. Inspect the inside of each tube and observe for metal loss

and/or deposits - use a flashlight to observe down thetube. Note the location of any tube showing deposit orcorrosion. Note the amount and nature of the deposit andobserve for trends (better or worse, if possible). Collectdeposit for analysis and take pictures to provide analyticaland visual documentation.

Note, the generating tubes may be covered with a baffleplate and inaccessible to view from the steam drum.These tubes can only be inspected from the mud drumunless the baffles are physically removed from the steamdrum. Make sure the baffles are properly in place and

secure before and after removal.

Mud Drum(s):

The mud drum typically will have more deposits compared tothe steam drum as it is the low point in the circuit. Often themud drum will not have any internals. Inspect each tube asdone from the steam drum and note location where metal lossand/or deposits are observed. If sludge removal appearsinadequate, review blowdown practices. Modifications may beconsidered to improve sludge removal (e.g., V notch angleiron can be installed to enhance sludge removal).

Economizer, Superheater, and Water Headers:

If available, inspect the economizer, superheater and all

water headers.Water wall headers may have removable end caps. If not, aninspection window may be cut when necessary. Theeconomizer and superheater are more difficult to access andconsequently get inspected less often or only whennecessary.Firetube Boilers

Inspection of a firetube boiler should consider all of thesame issues and include inspection of all key componentsrelating to observation of water line, integrity of theinternals, and noting deposit and metal loss location.However, all observations are typically made from man

holes and hand holes at the shell-side of this shell & tubexchanger. The same precautionary measures should btaken as with watertube boilers; however, some speciaproblems potentially exist: Carefully inspect the shell & tubes for O2 pitting especial

near the FW line inlet.. Transient deposits/sludge wtend to accumulate below the combustion chamber tubbetween the two hand holes even with a bottom blowdowregiment. This area must be cleaned thoroughly eveopportunity the boiler is opened (preferably once per yea

or more frequently during an on-line cleanup program). The front and rear tube sheets should be inspected fo

tube roll leaks, deposits, and oxygen corrosion. The reatube sheet in a refractory cooled design is especialsusceptible to problems since the tube sheet is exposeto residual heat from the hot refractory while thremainder of the boiler cools relatively quickly.

Fireside Inspections:

Often, the fireside inspection is overlooked or undervaluebecause so much emphasis is placed on inspecting thwaterside surfaces. However, inspection of the fireside wprovide valuable insight on waterside conditionAdditionally, it is not uncommon for a waterside problem

root cause to be a fireside problem.

Check for signs of tube overheating. Blisters or sagginare common indicators of overheating. Blisters arnormally found on wall tubes or tubes exposed to radianheat or possibly direct flame impingement (e.g., thburner area). Two common causes for blistering arwaterside deposits or excessive heat input (flamimpingement). Blisters can be spotted on the tube bshining a flashlight longways onto the tube observe foshadows created by the small bump. Sagging often wbe found in roof tubes or other horizontal-run tubes. Twcommon causes for sagging are water-starved tubes oexcessive heat input (flame impingement).

Check burners for deposits and wear. Check brick, tile and other refractory materials fointegrity. Note any loose, broken or degraded refractorDegraded or missing refractory will lead to tube overheain unexpected areas.

Check for deposits and metal loss. Note location annature of deposit. Water-soluble deposits (typicalwhitish and crystalline) are a good indication of a wateleak. A water leak would suggest failure of a tube, tubroll, or other water-containing component. Operationalla boiler with a tube leak would tend to undercycle, evewhen blowdown is reduced.

Ultimately, the boiler inspection is a measure of succesfor the entire boiler operation. Chemical treatment is ofte

not the root cause when problems exist. Good qualifeedwater is required (pretreatment, deaeration, ancondensate quality are key factors). Good blowdowcontrol is required. Proper mechanical operation required. The water treater and boiler operator togethemust assess the need for improvement and how to besachieve the improvement