Page 291 - Subyek Teknik Mesin - Forsthoffers Best Practice Handbook for Rotating Machinery by William E Forsthoffer

Be st Practice 5 .3 Steam Turbine Best Practices

Best
Best
Best Practice 5.3Practice 5.3Practice 5.3
Screen for proven blade row experience, energy per blade experience. Disqualification during the early stages of bidding saves
row (blade loading) and tip speed to ensure critical (un- the vendor proposal costs, which are significant.
spared) steam turbine optimum safety and reliability.
State in the invitation to bid document (ITB) that proven blade Lessons Learned
profile, energy per blade row (blade loading) and tip speed experience The use of prototype blading has resulted in costly blade
will be reviewed with each quoting turbine vendor prior to submitting failures for critical (un-spared) turbine applications.
a priced proposal.
Lack of proven experience should disqualify a quoting turbine Benchmarks
vendor for the project if they cannot change their design to incorporate
This best practice has been used since the 1980s, and resulted in
proven blading for each stage of the turbine.
smooth start-ups and trouble free steam turbine operation without any
Be sure to discuss disqualification with the vendor, noting that they
blade failures occurring.
will be considered for any future projects where they have proven blade

B.P. 5.3. Supporting Material - Transient torsional response experience review
(synchronous motors)
- Control and protection system
Typical compressor train pre-bid 3. Gear experience (if applicable) (vendor to include necessary
meeting agenda reference charts, tables, etc.)
- Gear box experience review and review of layout
The following agenda for a steam turbine drive compressor train drawing
is included for guidance purposes. Note: 1-2 days will be re- - Review of gear data sheet
quired for the meeting to review all details based on unit risk - Gear calculation review (in accordance with API 613)
classification. - Bearings e surface speed, load and experience
- Thrust loading e single helical gears
1. Compressor experience review (vendor to include necessary - Pitch line velocity review
reference charts, tables, etc.) 4. Auxiliary system experience (lube, dry gas seal and control
- Casing experience and review of compressor layout oil system)
drawing - Review of P&IDs
- Impeller experience (flow and head coefficient)
- Review of API 614 data sheets
- Individual impeller curve (location of rated point to - Review of typical arrangement drawings
impeller best efficiency point)
- List of experienced system sub-suppliers
- Impeller stress - Review of proposed dry gas seal supplier information
- Rotor response 5. Scope of supply for compressor train (all components and
- Stability analysis (if applicable) auxiliaries) review
- Bearings e surface speed, load and experience 6. Compressor train (all components) exceptions to
- Thrust balance specification
- Seals e surface speed, balance forces and experience 7. Meeting summary and action required.
- Surge control and process control system Note: Based on machinery risk, the following ‘design checks’
2. Steam turbine or motor experience review (vendor to may be required:
include necessary reference charts, tables, etc.)
- Aerodynamic
- Turbine casing experience and review of layout drawing - Thermodynamic
- Stage nozzle and blade experience (profile, velocity ratio,
- Rotor response
BTU/stage) - Stability analysis
- Blade attachment method and blade stresses - Seal balance
- Campbell and Goodman diagram review - Thrust balance
- Rotor response - Bearing loading
- Bearings e surface speed, load and experience - Control system simulations
- Thrust balance (reaction and hybrid types) - System layout maintenance accessibility
- Shaft seals

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