Why is the flue expansion joint old and bad? Find out where the root is first
The flue conditions in many factories are hot and corrosive, and dust washes. Non-metallic expansion joints (fabric fiber expansion joints) or metal rectangular expansion joints will age, crack and leak after one or two years of use. If you ignore it, as soon as the air leakage rate goes up, the energy consumption of the induced draft fan will rise, and even affect the desulfurization efficiency. Film repair sounds fresh. In fact, to put it bluntly, it means adding a layer of protective film to the surface or lining of the expansion joint to make up the damaged parts, and improve the corrosion resistance and wear resistance.
Exactly what problems can film repair solve? Depends on what kind of bad method your expansion joint is
For example, the skin of the non-metallic expansion joint is corroded by acidic condensate, or the bellows of the metal rectangular expansion joint is worn through a small hole by dust-at this time, the coating can block the damaged points and form an isolation layer as a whole. If the whole structure collapses and deforms, the coating can't be saved, and it has to be replaced. So the first step is to judge whether the surface coating or the structure itself is bad. You can't expect to use film to fix a bike that's falling apart, can you?
How to choose laminating materials and processes? Don't come up and post randomly
When the flue gas temperature is within 150℃, PTFE material such as rubber coating or PTFE compensator is quite suitable, which is acid-resistant and flexible. If the temperature reaches 300℃, you have to consider silicone or Teflon coating. During construction, the surface treatment is the most critical-the dust and oil in the flue must be cleaned up, and it is best to blasting and remove rust, otherwise the film will not stick firmly, and the bulge will fall off after two months. It is recommended to find an experienced team, and don't save that little labor cost. If you fool around yourself, the money you save won't be enough to buy regret medicine.
Mulching Repair or Overall Replacement, Which Is More Cost-Effective?
For a new non-metallic expansion joint, the cost of light materials ranges from several thousand to tens of thousands, plus the cost of shutdown, disassembly and crane, which is at least tens of thousands at a time. For film repair, the material cost is only about one-third of that of new parts, and the construction time is short, which can be done in the window period of minor repair of power plants. However, it should be noted that lamination can generally prolong the life of 2-3 years, which is not a permanent solution. If your equipment is almost scrapped, make do with it; If you have to use it for five or six years, it is recommended to replace it directly with a new one, such as replacing it with a corrosion-resistant metal corrugated expansion joint or a model with anti-corrosion coating. Do you think that's the case?
Let's talk about the actual case
Two days ago, a peer in a cement factory asked me that the rectangular non-metallic expansion joint on the flue leaked after less than a year. It was found that the flue gas contained high sulfur and the skin was corroded. Instead of replacing it with a new one, they repaired the interior with rubber PTFE composite film, and by the way, they also checked the surrounding smoke baffle doors. As a result, it has been running for another two years without any problems. Of course, I have also seen cheap and casual adhesive tape, and it will be wasted before a maintenance cycle arrives. Therefore, lamination repair is not a universal plaster, but it can really save a lot of money when used in the right place.