Steam Turbine is the power generating equipment. If steam turbines shut down for a longer duration it becomes a huge loss of power and it also affects on production rate.
There are many failures that occur in the steam turbine at running condition. Following are some major failures in a steam turbine.
- Blades failure – Blades generally failed due to crack which is the effect of fatigue, corrosion, pitting, and creep.
There are three main causes of blade failure – The cause of failure on the blade is influenced by several factors such as fatigue, creep, oxidation, corrosion, erosion, and surface degradation due to working at high temperatures. - Bearing failure – Bearing failure occurs due to abrasion, bond failure, cavitations erosion, corrosion, fatigue, overheating, surface wear, structural damage.
- Rotor Failure – This happens due to various stresses that can occur on the rotor. Various stresses can cause rotor failures – Thermal, magnetic, dynamic, environmental, mechanical, and residual. When installed and operated as designed, the stresses remain within tolerance and the motor operates properly for years.
- Steam Turbine Rotor Vibration Failures – If the rotor gets imbalanced it increases vibration. Vibration in the rotor also occurs due to casing because of temperature fluctuations.
- Blade Rubs – Running in the sealing of a high-pressure rotor caused bending of rotor and blade tip rubs.
- Casing misalignment – Rotor bending also occurs due to casing misalignment between two shafts of an integrated rotor can cause an eccentricity of the mass center of the rotor, and this eccentricity at high rotational speed will produce a centrifugal force in the radial direction, causing bending of the rotor.
- Failures can be caused by poor maintenance also.
To avoid all the above failures, the following prevention needs to take.
Stresses on blades can be reduced by making the blading stronger, using better design and quality, and by adding damping by means of caulking strips and lashing.
Bearing failures can be prevented by using the correct bearing design. Store bearings actively. Install bearings properly. Lubricate timely. Rotor failures – To prevent rotor failure, do not exceed the maximum speed and maximum mass limits for the rotor. Do not leave the centrifuge until the full operating speed is reached and appears to be running safely without incident. Stop centrifuge immediately if you notice any unusual noises or shaking. Clean the centrifuge daily or at least weekly. Remove the rotor and any sample or container holders. Interior cleaning includes the interior bucket specimen holder, rotor, and supports. To avoid rotor bending, the turbine should remain on turning gear until the high-pressure casing temperature is below 150C and the oil temperature is below 75C. Turtle Turbines has a well-trained and dedicated team for the maintenance of steam turbines. Turtle Turbines provide solutions for all types of failures in the steam turbines.
