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Boiler Inspection

Boiler Inspection. Rajan Bhandari Senior Lecturer SMA. BOILER INSPECTION REPORT ON “MT. ABCD”. Date / place of inspection: June 2000 at Keppel Shipyard. Singapore. Boiler : Mitsubishi MAC – 16 bar @ 40,000 kg/hr

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Boiler Inspection

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  1. Boiler Inspection Rajan Bhandari Senior Lecturer SMA

  2. BOILER INSPECTION REPORT ON “MT. ABCD” • Date / place of inspection: June 2000 at Keppel Shipyard. Singapore. • Boiler : Mitsubishi MAC – 16 bar @ 40,000 kg/hr • With reference to my shipboard visit / inspection carried out to the boiler, please find following report for your guidance.

  3. BOILER INSPECTION REPORT ON “MT. ABCD” • Steam drum -All internal fitting in excellent condition with minimal or minimal evidence of ferrous oxide deposits in the steam drum. ( before cleaning ) • Condition throughout on the steam drum boiler was very satisfactory, with evidence of magnetite layer present below and above the water line.

  4. BOILER INSPECTION REPORT ON “MT. ABCD” • Other area in way off shell appeared satisfactory, although trace of deposits (soft) was found along the lower section, this can be easily removed by high pressure water washing. • ** Sample of deposits was taken to Nalco Analysis Laboratory for deposits analysis test. • Water line looked not quite regular and is indicative of poor control/operation of water level.

  5. BOILER INSPECTION REPORT ON “MT. ABCD” • Generating and stay tubes opening (waterside ) noted satisfactory. • Mud drum- Inspection on the mud drum is generally good, although evidence of old corrosion ( passive ) around the shell surfaces noted. This can be improved and protect further by passivation process. • ** see recommendation.

  6. BOILER INSPECTION REPORT ON “MT. ABCD” • Generating tubes, riser and down-comers were inspected close-up and the condition is satisfactory. • Minimal or no deposit/debris noted in mud drum. Advised given to drained water totally to prevent active corrosion activities along the water line.

  7. BOILER INSPECTION REPORT ON “MT. ABCD” • Analytical Report. • Relatively high level of iron, indicating iron oxide formation due to high feed-water iron intake, which also indicating corrosion in Condensate, pre-boiler system or boiler. • Moderate levels of Sulphur, Copper, Zinc, Magnesium and Calcium residue. • This deposit analysis is consistent with the following scenario.

  8. BOILER INSPECTION REPORT ON “MT. ABCD” • Poor control of Condensate treatment (9-150) which resulting in excessive corrosion in post-boiler system, causing iron deposits to return back to boiler drum. • Insufficient BWT sludge conditioner and / or blow-down regime. • Poor control of oxygen scavenger reserved during boiler idle period.

  9. BOILER INSPECTION REPORT ON “MT. ABCD” RECOMMENDATION: Passivation: • Following the inspection and all other worked on the boiler, high pressure water washing is required to removed any mild scales, deposits and flash rust developed during repair period. It is essential therefore that prior to restarting the boiler to full operation, “bare” metal surfaces are re-passivated. This will protect the metal surfaces and extend the life of the boiler.

  10. BOILER INSPECTION REPORT ON “MT. ABCD” • After flushing of system and physical removal of any welding cleaning debris, a passivating boil out is now required. This is carried out by filling the boiler and adding sufficient hydrazine and alkali to maintain a ‘P’ alkalinity of around 300ppm and. a continuous hydrazine reserved around 5 ppm.

  11. BOILER INSPECTION REPORT ON “MT. ABCD” • For a 10 tonne boiler, this will require approximately 15 litres of 9-035+ and 5-7 litres of BWT Liquid +. The boiler should be fired and a low steam pressure raised to approximately 7.5 Kg per cm2 (100 psi, 7 bar). This should be maintained for 24 hours while testing the ‘P’ alkalinity and hydrazine reserves hourly. This rinse will form a protective magnetite layer, which will prevent further corrosion in the boiler.

  12. BOILER INSPECTION REPORT ON “MT. ABCD” • Once the passivating rinse has been completed, drain the boiler and refill with the initial fill of Nalfleet Boiler water chemicals for the normal programme.

  13. BOILER INSPECTION REPORT ON “MT. ABCD” • The recommendations in this cleaning procedure are general and based our information gained from past experience. Hydrazine Reserves: • To help maintain Hydrazine reserve in the boiler, keep the hotwell temperature as high as possible (but make sure that it does not interfere with feed pump operation, i.e. cavitation. • Test Hydrazine reserved immediately following sampling and prevent contact with the atmosphere as far as possible. If adhered to, this procedure will give the most accurate results.

  14. BOILER INSPECTION REPORT ON “MT. ABCD” Blowdown: • Blow-down should always be in accordance with the manufacturers’ instructions. However, boiler should be blow-down at least weekly to remove any sludge build-up and introduce fresh water, and additionally, at any time the chloride or dissolve solid exceed the stated maximum. Obviously, if supply of water on board is limited, this has to be taken into consideration.

  15. BOILER INSPECTION REPORT ON “MT. ABCD” GENERAL INFORMATION. • Nalfleet manual , MSDS , precaution cards, NIMS software application, dosing units and test apparatus are proved to be in good order. • A review of the treatment and dosage control program was carried out with the responsible engineer and he was satisfied that all issued were clearly understood. Advised given for 3/E to correction on the sampling and dosing point of Condensate treatment.

  16. BOILER INSPECTION REPORT ON “MT. ABCD” • An additional set of logpad for boiler and cooling water was supplied to vessel. • Chemicals stock check on-board:- • Alkaline treatment 9-512 1 x 25 ltrs • BWT Conditioner 9-304 1 x 24 ltrs • Condensate Treatment 9-150 4 x 25 ltrs • Hydrazine 9-035+ 4 x 25 ltrs • EWT 9-108 5 x 25 ltrs • Maxi-Vap+ 2 x 25 ltrs

  17. BOILER INSPECTION REPORT ON “MT. ABCD”Boiler steam drum • Condition throughout steam drum is in good condition with all internal fitting has no evidence of general corrosion and irregular water line noted.

  18. BOILER INSPECTION REPORT ON “MT. ABCD”Boiler steam drum • A general & close-up view shell surfaces and feed line

  19. BOILER INSPECTION REPORT ON “MT. ABCD”Boiler steam drum Condition are satisfactory, with magnetite layers still visible throughout the drum.

  20. BOILER INSPECTION REPORT ON “MT. ABCD”Boiler water drum General view of water drum with evidence of old (passive) pitting noted around the shell surfaces.

  21. BOILER INSPECTION REPORT ON “MT. ABCD”Boiler water drum • General close up view of water drum and internal condition of bottom header..

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