When the TRT blade is working, it is unavoidable to be damaged by it, so what are the reasons for the damage of the TRT blade? In response to the phenomenon that the blade is damaged, what should we do? TRT Repair Woolen cloth? The following are the causes and repair methods of TRT blade damage. Hope it helps you!

1. Cause of damage

TRT (Top Pressure Recovery Turbine) works in harsh environments such as a lot of soot, corrosive gas and scrubbing water, and the gas directly discharged from the top of the furnace contains untreated and clean dust. This will cause sharp wear and corrosion to rolling vanes and stationary vanes, and wear and cracks are often caused at the root of the vane due to erosion and corrosion.

1. The scouring effect of airflow

Due to the scouring effect of the soot on the rolling blades, with the increase of the working time of the unit, the moving blades on the rotor and the stationary blades on the stator will gradually wear out. Finally, the mechanical function of the blade will be reduced (the thickness of the blade will be reduced by more than 4%), and the decline in function can be judged by analyzing the working data.

2. Corrosion effect of medium

Near the root of the blade, along with the loss caused by gas, water vapor corrosion and corrosion, if the strength of the blade decreases and the change of the dynamic and static natural oscillation frequencies causes resonance, it may also cause cracks in the stress concentration part of the root of the blade and continue to expand. .

Corrosion of the buried part of the rolling blade. The rolling vanes and the embedded parts of the vanes are triangular and fixed by means of axial penetration.

In terms of design, the root piercing part of the rolling blade and the rotor embedded groove have gaps, so during the working process, gas will enter the gap, causing partial corrosion, and there is a possibility of further cracks. Under certain circumstances, when working continuously for a long time, there is a risk that the blade will rupture and cause a major accident.

In order to check the blade loss and cracks, it is necessary to carry out sufficient inspection and anti-corrosion treatment, which requires a construction period of about 30 days, but because the total construction period of regular maintenance every year is only about 20 days. Therefore, the actual situation is that the inspection about cracks that may cause major accidents in the future is not complete. The general method is to perform magnetic particle inspection and inspection of the blade installation frequency on the blade after the rotor has cleaned the blade surface.

2. Repair method

1. Carry out cermet coating wear-resisting treatment on TRT rolling blades and stator blades, and then dry them, carry out demagnetization, electrical error test correction, and do dynamic balance test.

2. The embedded part of the moving blade. In the place where pitting corrosion occurs, because there is the possibility of cracks occurring at the stress concentration part at the bottom of the pitting corrosion, it needs to be removed by grinding. After removing the pitting corrosion, magnetic particle inspection and ultrasonic inspection are carried out. Therefore, the rolling blades should be pulled out regularly and the coating treatment should be carried out from scratch.

The dry TRT should be coated with silica tungsten resin in the gap to avoid the intrusion of smoke and dust. There are two methods of coating, either by brushing to form a thin film, or by filling the entire gap. With regard to the intrusion of soot, the backfill coating, although having a better avoidance effect, requires a longer repair period than the thin-film method.

3. Spare leaves. Prepare the spare blade before the regular inspection. When the inspection finds a problem, the TRT can be restored by simply replacing the spare blade, which has the advantage of shortening the maintenance period. In addition, the disassembled blade can not be restricted by the regular maintenance period, so it can take time to carry out fine correction and coating treatment with excellent anti-corrosion effect.