Power plant boiler maintenance
Thread Content
The power generation boiler has a capacity of 35 tons per hour; according to thickness measurements, the wall thickness of some of the water wall tubes is ≤3.5 mm. They need to be replaced as per the regulations; there are about 15 of them in total. Its length is about 1 to 2 meters. Now, I would like to invite a company with the necessary construction qualifications to carry out the repairs. Is it necessary to go through notification procedures? Is there a fee for the notification procedure? If I accept it, how much? After replacing the water wall tubes, non-destructive testing is required – should it be done on all of them or only on some? Try pressurizing again. Finally, it is necessary to invite an inspection from the boiler inspection agency; how much is the inspection fee? Please, dear friends, help me out
Although according to the regulations, water wall tubes should be replaced when the wear thickness exceeds 1/3 of the tube wall thickness, for example, in the case of medium-pressure boiler water wall tubes with an outer diameter of 51 mm and a wall thickness of 5 mm, our regulation states that the tubes must be replaced once the wall thickness drops below 2.5 mm; therefore, replacing the tubes at a thickness of 3.5 mm is a bit premature – they can continue to be in use. What’s important is to carry out regular inspections and implement anti-wear measures both during operation and during maintenance. As for the procedures and costs associated with maintenance work, there is absolutely no need for them; a qualified maintenance company can handle the replacement of pipes on a large scale. After the work is completed, a hydrostatic pressure test at working pressure can be carried out first to verify the quality of the welds, followed by further processing. Finally, an overpressure test at 1.25 times the normal pressure must be conducted as required. It is necessary for the local pressure vessel inspection department to be present during this test; of course, if your superior authorities have a department with the qualifications to inspect pressure vessels, that department can also be involved.