Boiler maintenance issues
Thread Content
Three existing 220t/h boilers have completed their hydrostatic testing, but due to reasons on the part of the owner, these boilers will not be started up for heating until after next Spring Festival. During such a long period, it is necessary to carry out maintenance on the boiler units in accordance with relevant regulations. Currently, the wet maintenance method is planned to be used. Could anyone with experience advise on what aspects should be taken into consideration when performing wet maintenance on boilers? Especially such a long period of maintenance.
The maintenance of boilers is a major task. The shutdown time mentioned by the poster seems to be almost a year. For wet maintenance, a shutdown period of no more than one month is generally acceptable. Moreover, the furnace should be regularly heated on low heat to keep the outer surface of the heated surfaces dry. Using the wet method for a whole year is not very good. It should be reconsidered. Nitrogen is generally better for long-term maintenance. Both the cost and maintenance efficiency are economical. Ensuring a certain slight positive pressure is sufficient. Last year, due to the effects of the economic crisis, production was halted. The boilers in our facility are protected using nitrogen. It works very well. 3.10 After opening, check that the metal inner wall is free from corrosion.
It is recommended that the poster use dry method maintenance; the wet method requires a shorter duration and further testing, while with the dry method it is sufficient to ensure the proper pressure in the boiler. Our system is equipped with air separation units, so the source of nitrogen is quite convenient.
As the people above have said, maintenance over a period of one year falls under long-term maintenance, and wet methods should not be used for it. Both dry maintenance and inflation maintenance are used for the maintenance of boilers that are out of use for long periods ； The dry method involves draining the water from the boiler and drying it out after it has been shut down, followed by placing a desiccant or an anti-corrosion gas inside the boiler. Absorbents commonly used include calcium chloride, silica gel, and quicklime, with a dosage of 2–3 kg/m3. After placing the absorbent in the pot, close all access openings, and then check and replace the absorbent regularly. The inflation method involves filling the boiler with the inert gas nitrogen or ammonia, which has anti-corrosive properties; the pressure of nitrogen should be 0.3 MPa gauge, with a purity of not less than 98.5%. Ammonia gas should be introduced from the top of the boiler; once filled, a gauge pressure of 0.013 MPa should be maintained, with a dosage of 0.6 kg/m3.