Aalborg Mission OL
Boiler Spare Parts
Membrane-wall furnace · KBO and KBE burners · Refractory and gaskets
The letter after Aalborg decides what the heating surface is made of
Boilers reach this site through the marine boiler sourcing guide, which covers the families a fleet meets and the two-plate problem every boiler enquiry starts with. This page goes one level down, into the oil-fired OL.
For the other Aalborg boilers, the OS, OC, D and XW lines and the KB burners, see Aalborg boiler spare parts.
Top-fired, two drums, membrane walls
A vertical cylindrical water tube boiler with an upper and a lower drum joined by straight tubes, fired from the top. The furnace is built of membrane walls with gas-tight polygonal panels, which the maker credits with resistance to gas pulsations, and the convection section is of straight pin tubes with bent pins. Circulation comes from putting the downcomers outside the membrane walls.
Neighbours with different tubes
The oil-fired OS is a vertical cylindrical boiler whose pin-tube elements double as heating surface and as support for the furnace top plates. The OC is a composite: an oil-fired section with pin tubes and an exhaust-gas section of bare smoke tubes. The letters choose the tube, so a tube enquiry naming only Aalborg has not named the part.
The plate may carry the older name
This boiler was sold as MISSION OL, and the maker's current literature writes it as Aalborg OL, formerly MISSION OL. The smaller OS carries the same note, formerly MISSION OS, so the word MISSION alone does not make a boiler an OL: the two letters after it do. Aalborg Industries itself passed to Alfa Laval under an agreement announced in December 2010 and completed in 2011. Three names, one boiler; an enquiry is easier to answer when it says which is stamped on the shell.
The boiler may be doing the economiser's paperwork
The OL is documented as able to serve one or more exhaust-gas economisers as a shared steam drum for waste heat recovery. A request written against the boiler plate can therefore concern gas-side surface belonging to a different unit, which fouls and corrodes on its own schedule. Say which side the work is on.
A membrane-wall furnace does not have a brickwork order
The design decides the recurring lines, and here it decides them against expectation in three places.
Start with refractory, because it is what a buyer expects to order and largely is not here. The furnace of an OL contains minimal refractory: the maker describes the integrated burner design as reducing it to a protective layer at the bottom of the furnace and around the access doors. Two zones, both shaped to their openings, and nothing like the side-wall and roof brickwork that fills an older boiler enquiry. What recurs instead is the membrane panels and the pin tubes, and a pin tube is not identified by a length: the material, the bank it belongs to and whether the ends are expanded or welded are what place it.
Then the burner, the line most often quoted from the wrong document. The maker's own burner designations are not variants of one another — the atomising principle changes with the letters. For the OL the maker recommends the KBSD, a steam-atomising burner built for its top-fired boilers and delivered pre-mounted; the KBSA is the steam-atomising type for its side-fired boilers; the KBO pressure jet and the KBE rotary cup belong to the small OS and OC boilers. Third-party burners appear on these shells too, and the maker's own spares list covers several of them. So an atomiser request needs the burner's own designation. On a KBSD the main atomiser is a steam-atomising element of the Y-jet kind, identified from the burner rather than from a stamp, and the small nozzle it does carry belongs to the fixed ignition burner, which has its own nozzle, oil pump and ignition transformer.
The third thing is the fuel the boiler has been burning. For the 2020 sulphur cap the maker put out its 2020 Spare Parts Kit — gaskets, sealings and replacement nozzles for fuel line and burner components — on the reasoning that the acidic content of low-sulphur fuel adds wear to burner parts, gaskets and sealings and raises the risk of a stoppage. That kit is chosen by something no designation reveals: whether the fuel line is the Single-Line or the Double-Line Fuel System, the two configurations it is offered for. Boilers delivered before 2010 left the yard with the simpler Original Fuel Line System, which the maker states is not designed for MGO; most have since been upgraded, and which system is fitted now is a question for the engine room, not the plate. That sums up this page — on a boiler the question is rarely which model, and usually which arrangement.
What an Aalborg OL order is built from
Grouped as the maker groups its own boiler spares: mountings and valves, the water level group, pumps, the burner with its control and safety equipment, the electrical side and the draught fan — then the pressure part.
- Boiler mountings and their gaskets
- Safety valves, their springs and the sealed setting record
- Main steam, feed, blowdown and scum valve components
- Water level gauge glasses, gauge sets, cocks and packing
- Water level transmitters, electrode columns and probes
- Low water level cut-out devices, and feed water pump repair kits
- Burner guns and steam-atomising atomiser elements of the Y-jet kind
- Ignition burner nozzle, oil pump and ignition transformer on KBSD and KBSA burners; pressure-jet nozzles and rotary cup parts where a KBO, a KBE or a third-party burner is fitted
- Ignition electrodes, cable and transformers, flame sensors and flame relays
- Fuel oil solenoid valve groups, single-line or double-line as built
- Fuel line gaskets and sealings rated for low-sulphur duty
- Burner and draught fan components, dampers and linkage
- Wind box parts, burner mounting seals and burner safety management items
- Control panel equipment: relays, contactors, timers and control cards
- Membrane panel and pin tube renewal items with material and bank stated
- Refractory for the furnace bottom and around the access doors
- Manhole, handhole and access door gaskets
- Soot blower components where fitted, and overhaul gasket and sealing kits
A safety valve and a gauge glass are not the same kind of purchase, though they arrive on one list: the glass and its packing are crew consumables, while the valve is set on a rig, sealed and accepted against the approved arrangement, so it must match that arrangement rather than merely fit. Safety valve context sits on the LESER and Fukui pages.
Two plates, one fuel history, and the figures read rather than quoted
Where a figure decides a line — a set pressure, a working pressure, an output — this page prints none. Read it off the plate, the valve body or the certificate: the number on your machine is the only one that answers the question.
- Boiler plate photographed whole: maker name as stamped, designation, serial number and the figures it carries
- Burner plate photographed separately, usually on another housing and often from another maker
- Burner designation and, from it, the atomising principle — steam-atomising on a KBSD or KBSA, pressure jet on a KBO or KBM, rotary cup on a KBE, the successor of the KB — and, on a steam-atomising burner, whether the fuel oil valve is still pneumatic or has been changed to the electric valve the maker offers as an upgrade
- Fuel line system as fitted today — the pre-2010 Original Fuel Line System, or the Single-Line or Double-Line Fuel System it may have been upgraded to — for anything on the fuel or sealing side
- Fuel actually burned in service, and when the boiler changed over
- Whether the boiler serves an exhaust-gas economiser as a shared steam drum, and which side the work is on
- Whether the boiler was built or converted for a second fuel (LNG, methanol or ammonia) or as an electric hybrid, or delivered multi-fuel-ready or hybrid-ready for later conversion, since a converted boiler is read from its own drawings
- For a tube line: material specification, the bank it sits in, and whether the ends are expanded or welded
- For a refractory line: the furnace bottom or an access door surround
- For a safety valve: the stamped setting, the nominal size and flange rating, and the maker
- Class society, the date of the last boiler survey and the certificate requirement
- Water treatment the boiler has run on, since chemistry decides what is found when the drum is opened
- Control system generation — an older Unisab controller, or Alfa Laval Touch Control, which the maker offers as the replacement as Unisab controllers reach the end of their life
- Photographs of both plates, of the burner front, and of the failed item in place
Tools for this equipment: the valve body marking reader for the size, class and material cast on a safety valve body, and the flange identifier for its flanges. The gauge glass size finder names a flat level gauge glass from its size or a measured length. For the steam side, the steam saturation calculator gives the saturation temperature for the working pressure on the boiler gauge. For the water side, the blowdown calculator works out the blowdown from the feed water and boiler water readings, and the pipe heat loss calculator gives the heat lost from a steam line, insulated or bare.
The burner is a repair, the pressure part is a project
A boiler list mixes items a crew fits in an afternoon with items a surveyor must accept, and the routes diverge there.
The burner and its consumables are the working half. Atomiser elements, nozzles where the burner uses them, electrodes, ignition cable, flame sensors, solenoid valve groups, fuel line gaskets and sealings, fan and damper parts: these come round on their own rhythm, the rhythm has shortened on low-sulphur fuel, and a crew can often restore a burner with the right parts aboard. Where a buyer's approval requirements allow it, a verified alternative route can be reviewed on items of that kind, with dimensional data and material documentation checked at RFQ stage — and on the sealing side material matters more than dimension, since that is what the fuel change attacked. An OEM-route review can be requested on the same lines instead.
The pressure part and the protective devices go the other way. Membrane panel and pin tube work, drum internals, and the safety valves and low water level devices a surveyor tests and records are matched to the approved arrangement for that boiler rather than to a dimension: a valve reset or resprung is certified again, and a tube is placed by its material and its bank. Where a safety valve is resprung, the compression spring calculator sets the old spring and the new one side by side by rate and by load at the fitted length, before the valve goes back on the rig. Vessel Core puts these on an OEM-route review and says so before pricing. Between the halves sits the control and safety management equipment, where the route depends on the panel generation. Vessel Core is an independent spare parts supplier and names the route against each line, so a burner kit and a survey item travel in one request without either being answered wrongly.
Aalborg Mission OL parts — questions buyers ask
My plate reads MISSION OL. Is that the boiler you mean?
Yes. The maker's current literature writes this boiler as Aalborg OL and notes the former MISSION name itself, and the Aalborg boiler business passed to Alfa Laval under an agreement announced in December 2010 and completed the following year. A shell stamped Aalborg Industries, a document headed MISSION OL and a catalogue reading Aalborg OL describe one machine. Send the plate as it reads.
How much refractory does this boiler take?
Far less than the question expects. The furnace is built of membrane walls and contains minimal refractory; the integrated burner arrangement reduces it to a protective layer at the bottom of the furnace and around the access doors. There is no side-wall or roof brickwork order here. What recurs is the membrane panels and pin tubes, plus access door and manhole gaskets whenever something is opened.
Can you quote an atomiser from the boiler model?
No, and it is worth knowing why. The burner is a separate designation with a separate plate, and within the maker's own range the atomising principle changes between designations: the KBSD recommended for the OL is steam-atomising and comes pre-mounted on top-fired boilers, while the KBO is a pressure jet and the KBE a rotary cup, both met on the smaller OS and OC boilers. Third-party burners are fitted to these shells too. On a KBSD the main atomiser is of the Y-jet kind, read from the burner documentation, and the only small nozzle is the one in the fixed ignition burner. One photograph of the burner plate answers it.
Why do you ask what fuel the boiler has been burning?
Because the parts that fail changed when the fuel did. The maker put out its 2020 Spare Parts Kit for exactly this, on the basis that the acidic content of low-sulphur fuel adds wear to burner parts, gaskets and sealings. Which kit applies is decided by whether the boiler has the Single-Line or the Double-Line Fuel System, which no designation reveals; neither kit is built for a boiler still on the pre-2010 Original Fuel Line System, which the maker states is not designed for MGO. Fuel and arrangement move a sealing enquiry from guesswork to a material question.
Which Aalborg OL parts can go on an alternative route?
The burner side and its consumables: atomiser elements, nozzles where the burner uses them, electrodes, ignition cable, flame sensors, solenoid valve groups, fuel line gaskets and sealings, fan and damper parts. Where your approval requirements allow it, a verified alternative can be reviewed on those, with dimensional data and material documentation checked at RFQ stage; on the sealing side the material matters more than the dimension. Membrane panel and pin tube work, drum internals, safety valves and low water level devices are matched to the approved arrangement for the boiler, so Vessel Core puts them on an OEM-route review and says so before pricing.
Is Vessel Core connected to Alfa Laval or Aalborg Industries?
No, and there is no agreement of any kind. Vessel Core holds no dealership, distribution, representation or partnership agreement with Alfa Laval or Aalborg Industries, and quoting a component against one of their designations implies no approval by the maker and no claim of interchangeability.
Submit your RFQ now.
Send the boiler nameplate — or the burner's own plate, if the item sits on the burner rather than the shell — the fuel currently in use, and the component description or part number. Vessel Core reviews which section of the boiler the request falls under before a quotation is prepared.
