Fired Heaters, Steam Generators and Incinerators

General

The contents of this section applies to the main items of fired heaters, steam generators and incinerators. Where associated motors, instruments and electrical items are concerned, reference should be made to the relevant sections.

For preservation of steam boilers see Reference 9.13.5.

Where vendors provide recommendations for site storage and protection these are to be followed and take precedence over the recommendations contained in the appendix.

Where prolonged site storage is involved, which is not under the control of vendors concerned, equipment guarantees are invalidated. However, most vendors offer an on site re-furbishing services after which equipment guarantees are re-instated. Clients are recommended to employ this type of service wherever necessary.

A warm, clean, dry and vibration free environment in a secure under cover storage area is required for Panels etc. Recommended environment conditions are temperature range of 15°C to 30°C and a humidity of between 30 to 40%.

Fired heaters and Incinerator parts to be stored in level and up-right position.

Fired heaters and Incinerator parts transportation supports and temporary stiffeners to be checked for soundness and repaired where necessary.

When refractory lined steel sections of heaters, furnaces or boilers are stored outside care must be taken that water can not enter between steel and refractory in order to avoid corrosion that can cause cracking of refractory covers are mandatory.

Ensure all name plates and Tag labels are intact and secure.

Protection

The cleaned boiler shall be thoroughly drained, dried and can be protected as follows:


A gasketed cover on all manholes.

Close all other openings tightly.

Pressurize with nitrogen.

Close the inert-gas inlet and leave the vessel blanketed with inert gas at 0.5 bar(g).

All exposed bolts and flanges shall be coated with a heavy grease.

Determine the appropriate external protective measures as dictated by local conditions. Ensure that the external surfaces have been painted, coated or insulated as per the specification.

Boiler Feedwater Systems

Header Boxes and Casing

Hinges on header doors, peepholes and access doors shall be coated thoroughly with a heavy grease. Where seating surfaces of openings could corrode because of leakage of rain or moisture, it is advisable to seal the doors with a readily removable mastic.

Burners

Treatment of this equipment is dependent upon the type of burner used, and some will require more care than others. The movable parts shall be covered with heavy grease to protect threads or adjusting mechanisms. Spray nozzles shall be removed, tagged and stored. Fuel supply openings shall be blanked off and secured.

Combustion

Chamber If the combustion chamber is to be preserved, burner holes shall be closed. Protection recommendations shall be checked with vendor's recommendations. Inert gas bleeding can be carried out or moisture absorbents used. Selection shall be made in conjunction with vendor representative.

Breeching and Ducts

For internal surfaces absorption of moisture during the idle period shall be minimized by closing the ducts. Expansion bellows shall be inspected. Operating mechanisms on the dampers shall be coated with heavy grease such as Shell Rhodina to ensure operability when in service. Operate dampers periodically and verify functioning.

Refractory

Refractories shall be kept dry and free of frost at all times. Atmospheric moisture can be excluded by capping stack and duct openings and by sealing locations where water or moisture can enter. Refer to vendor's recommendations.

Tubes

All tubes shall be dried, the headers shall be closed and nitrogen blanket applied at 0.5 bar(g). Nitrogen pressure shall be checked periodically.

Steel Stacks

The stacks shall be capped. External inspection of paint shall be in conjunction with the specification. Particular attention shall be paid to ladders as these are safety items.

Fans


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