Flex-Power Services™

Solution

The Modified ST Valve Staggering upgrade is designed to support lower load operation and to reduce loss of efficiency in this operating condition.

Amongst other criteria, minimum load is typically restricted by logic to avoid high HP exhaust temperatures, and may lead to opening of bypass stations or even shutdown for protection.

The Modified ST Valve Staggering introduces an upgraded logic which has been designed to facilitate modified operations to support lower minimum part load with same or improved margins.

Intended Benefits & Scope

The Modified Valve Staggering upgrade modifies the valve staggering logic for part load operation to help:

• Avoid losses from opening of the IP bypass station
• More efficient operation in part load
• Lower potential for tripping on high HP exhaust temperature
• Lessen throttling of reheat control valve

Scope

• Assessment of current part load operation
• Engineering and implementation of the recommended process logic changes
• Typically no hardware changes required

Intended Benefits

Many Gas Turbines have been designed to operate most efficiently at maximum load conditions. With today´s changing market, the need to efficiently operate at part load is becoming more important as well. Siemens Energy has developed a range of solutions to enhance part load capabilities, which can help to:

• increase operational flexibility
• reduce part load fuel consumption
• reduce minimum emission compliant part load
• enhance part load efficiency

Intended Benefits

With natural cooling, it may take multiple days for a steam turbine to be sufficiently cooled down to access for inspection or outage work.

Through extensive analysis, Siemens Energy is able to offer Fast Cooling of Steam Turbines which has been designed to significantly accelerate cool-down time and thus help get access to components sooner after shutdown.

Scope

• Engineering & Process optimization - Detailed analyses of the cool down process taking into account material strength limits, plant specific operating variables and usage factors. Site specific check of the existing cool down procedure and engineering of optimized process
• Hardware modifications - improvements for accessibility, ease of activation can be proposed and implemented
• Automation - degree of automation of the cool down process can be increased and optimized.

For turbines already equipped with the forced cooling system, Fast Cooling may offer incremental optimization, e. g. improved handling and automation, improved process, etc.

Intended Benefits

Steam Turbine standstills can lead to increased exposure to air moisture which can result in parts corrosion. Preservation measures are recommended to remove and control residual moisture to below recommended thresholds.

Siemens Energy has developed an enhanced preservation system for steam turbines and its auxiliaries to support more flexible shutdowns and longer standstills.