Why does the return furnace check the ash of the superheater
Local wear is common in superheater and reheater. The parts with severe local wear and tear are near the pipe, wall piercing pipe, bend pipe, and the parts in contact with the pipe clamp near the slope wall at the outlet of the furnace. Because these parts are easy to appear flue gas velocity, ash concentration local increase phenomenon, so that wear aggravate. The wear characteristics of horizontal superheater and reheater are similar to that of coal economizer. Wear and tear condition of the above part should be carefully checked during maintenance.
If the superheater or reheater is found to be blocked by ash during maintenance, the wear condition of the pipe above the ash plug and the pipe without ash should be carefully checked. The local increase of fly ash concentration will occur at the top of the ash plugging area. After the ash plugging, the flue gas flow breaking area will decrease and the flue gas velocity at the non-plugging area will increase, which will aggravate the wear. At the same time, attention should also be paid to the inspection of pipe expansion roughness in these parts, as the creep rate may be accelerated due to excessive temperature due to the strengthening of heat absorption. In addition, changsha dingli technology believes that it is also necessary to check the pipe near the furnace ash blower.
The problems that are easy to meet in the overhaul of coal economizer are pipe wear, inner wall corrosion, pipe leakage and so on.
Economizer is easy to wear parts, maintenance to check the wear and tear on parts carefully, for wear device summon, skew, fall off of the tube, check more should focus on the wear and tear. If the local wear of the pipe exceeds the standard, it can be repaired by surfacing welding. If the wear area is greater than 10cm2 or the wear thickness is more than 1/3 of the original wall thickness, the new pipe shall be replaced. Repair or replacement of damaged or deformed anti-wear devices.
The inner wall corrosion of coal economizer is mainly caused by incomplete oxygen removal, low water speed and low pH value of feed water. When repairing, we should cooperate with chemical professionals, cut the representative pipe section, check the corrosion condition of the inner wall, and determine the anti-corrosion countermeasures.
The leakage of coal economizer in return furnace is caused by wear and perforation of pipe, spot-shaped corrosion perforation of inner wall, or lack of solder joint sticking, especially the defect of solder joint. The welding joints made by coal economizer are mostly welded by touch. The welding head may have defects such as unhardened penetration and slag inclusion, which will lead to water leakage after long-term operation.