Service for Steam Turbine SST-100
General Information
- Description
The SST-100 is a single-casing multi-stage steam turbine, providing geared drive to 1,500 and 1,800 rpm generators and packaged in a base frame-mounted design.
For SST-100 steam turbines, Siemens feature a major portfolio of service solutions and products to help optimize efficient plant operation.
This service can include:
- Performance Maintenance
- Performance Enhancement
- Service Programs
- Product-Related Services
- Training and Consulting
Our Portfolio (3)
Self-Lubricating Sliding Plates
- Background
- Improvement
- Scope of Retrofit
- Benefits
The front-end bearing pedestal is arranged in a sliding configuration on the sole plate to be able to accommodate the thermal expansion of the turbine.
The intention must be to keep the displacement forces exerted by the front-end bearing pedestal on the sole plates and thus the coefficient of friction as small as possible. Only then uniform expansion and contraction of the bearing pedestal is possible without any abrupt movements.
After a longer period of operation the sliding behavior deteriorates increasingly as a result of contamination, corrosion, consumption of the initial lubricant and wear of the moving surfaces. Fig. 2 shows the typical condition of a sole plate of customary design after approx. 50,000 operating hours.
By backfitting self-lubricating sliding plates as a support and sliding surface for the bearing pedestal the friction coefficient is calculated to be more than halved compared to that with the steel plates previously used.
The self-lubricating sliding plates (DEVA plates) are made of a tin/copper (bronze) alloy. The outstanding self-lubricating properties of this material are attained through the addition of a solid lubricant in the form of graphite.
In larger types of turbines the sole plates used to date are replaced with so-called window plates, in which a different number of self-lubricating sliding plates are installed depending on the size of the bearing pedestal.
Potential Benefits
- Small coefficients of friction during expansion and contraction of the turbine casing and thus reduction of load on the axial connecting and fixing elements and on the casing, bearing pedestal and foundation.
- Continuous sliding of the bearing pedestal during startup and shutdown without any abrupt movement in terms of absolute and relative expansion.
- Reducing the potential for tilting or skewing of the bearing pedestal as a result of high friction-related sliding forces and thus uniaxial, impermissible bearing loadings (edge supports).
- Ease of replacement of the sliding plates.