Upgrades and retrofits

Ansaldo Energia has designed, manufactured and commissioned more than 1100 steam turbines throughout the world: geothermal and cogeneration steam turbines (for process steam, district heating, desalinisation,), steam turbines for fossil fired cycles and combined cycles.
This extensive experience has enabled Ansaldo Energia to achieve a high level of reliability and efficiency as well as a remarkable flexibility in terms of adapting to different steam conditions and plant arrangements.
Based on its OEM experience of over 87 GW of steam turbines, Ansaldo Energia has developed various solutions of Upgrades and retrofits which extend and/or improve the plant performance and its operational life, and generate the benefits of a virtually new turbine without the drawbacks of high investments, high technical risks and long realisation times.
Ansaldo Energia Engineering has developed powerful analytical methods, impressive advancements in materials and unparalleled understanding of their operational performances.
Both as an OEM and an ISP, Ansaldo Energia and Ansaldo ESG are broadening day after day their first-hand know-how and know-why in a number of steam turbine makes and models, both reaction and impulse types.
Upgrades and Retrofit solutions can be provided to all of them.

UPDATED SOLUTIONS FOR EFFICIENCY RECOVER

Advanced New Blading Design

• Application of 3D Blading on HP-IP section to improve profile and reduce secondary losses
• Blading for Ultra Super Critical applications

Last Stage Blades (LSB)

• Longer LSB to reduce exhaust losses and convert them into additional power output
• Wide range of Last Stage Steel Blades, up to 48”, with annular area of 12 m²

Brush Tip Seals

• The application of “brush” tip seals reduces steam leakage and improves the stage efficiency

Materials

• Improved and upgraded materials for high temperature applications up to 600°C

Steam Turbine Control Systems (STCS)

• Specifically designed by Ansaldo Energia with digital, precise, reliable and completely automatic technology, managed from the control room
• Replacement/upgrade of inflexible speed/load mechanical controllers and protection systems
• Replacement/upgrade of old generation supervisory systems
• Continual updating in order to comply to the latest regulations.

APPLICATIONS

Repowering conventional steam cycles into combined cycles

• Transformation of a conventional plant into a combined cycle can reduce the lost energy to about 45%
• The net efficiency of a repowered combined cycle is around 55% (the efficiency of a typical conventional cycle being of about 35%)
• Repowering a conventional plant requires modification of the steam generation equipment and adaptation of the steam turbine to the new steam parameters (see Retrofits below)
• In Repowering projects there is generally a mass flow increase in the LP section: a longer LSB can reduce losses and convert them into further additional power.

Repowering GT Open Cycles into Combined Cycles

• Transformation of an open cycle into a combined cycle can reduce the lost energy to about 42%
• The net efficiency of such repowered combined cycle can be around 58% (the efficiency of an open cycle being typically of about 35%).

Steam Turbines Retrofits, Rehabilitations and Upgrades
Performance improving of the steam turbine is needed:

• to match the new steam parameters of a combined cycle Repowering
• to exploit the increased capacity of upgraded boilers
• to increase the plant heat rate without changing steam parameters (e.g. by adopting enlarged LP flows to reduce exhaust losses and increase steam turbine efficiency)
• to enhance reliability and extend life time

Impact on the equipment:

• Partial replacement of blading on existing stationary and rotating parts
• Replacement of complete inner blocks (steam path, rotor, inner casing)
• Replacement of complete turbine sections
• Introduction of advanced steam path technology
• Improved gland seal arrangements

SPECIFIC UPGRADE SOLUTIONS ON TURBOGENERATORS

• Resin Injection
• Life Extensions
• Stator Re-winding
• Insulations
• Retaining Rings with advanced materials
• Auxiliaries and Excitation Systems

In the last 10 years Ansaldo Energia has realised more than 50 major interventions on steam turbines and generators, some 20 being Repowering projects.