With the increasing amount of renewable generation coming online to the North American power grid and the inherent variable nature of these generation sources, fossil fuel fired generation is being called upon to cycle more frequently. With the low natural gas fuel prices currently in the market, Combined Cycle gas generating units are carrying a large portion of this cyclic load following.
A Combined Cycle unit that can efficiently cycle can gain additional market revenue by capitalizing on higher market pricing opportunities.
These cycling activities will eventually take a toll on the generation equipment, especially the steam
turbine and its components. Continual cycling subjects the equipment to heat stresses, especially the rotor,
turbine blades and the turbine shell. If uniform temperatures are not maintained across the turbine shell
and within the turbine casing, rubbing and binding may occur between the rotating and fixed turbine
Cyclic fatigue stresses will eventually lead to higher maintenance costs, lower reliability and the eventual failure of equipment.
A Turbine Warming System (TWS) is a cost effective way to alleviate many of the heat stresses and metal fatigue associated with cycling. A TWS will maintain a uniform temperature gradient across the entire turbine shell and alleviate component damage that occurs with differential expansion.
A properly installed and maintained TWS has an expected life of 10 years or more. The investment to install the TWS creates an ROI for years to come.
Installing the TWS will greatly reduce thermal stresses on the equipment and increase equipment life even beyond manufacturer’s Starting and Loading chart values. Cyclic fatigue stresses will eventually lead to higher maintenance costs, lower reliability and the eventual failure of equipment.
A key component of the start-up process is the amount of time necessary to match steam and metal temperatures within an acceptable temperature tolerance range. Cold starts where a unit may be idle for 48 hours or more, are theoretically eliminated. Warm starts of 24 hours or less are greatly reduced and hot starts are reduced to a lesser degree. The TWS solves the Start-Up problems by always maintaining the steam turbine in a “Hot” start condition.
Using the TWS, an Operator can control and maintain steam turbine metal temperatures in a “Hot” start condition. The system will also precisely control shell temperatures to avoid “humping” the shell and radial rubbing during start-ups. If uniform temperatures are not maintained across the turbine shell and within the turbine casing, rubbing and binding may occur between the rotating and fixed turbine components.
The TWS includes stand-alone control system with one or more control screens. Optionally, PSI can assist with integration of TWS monitoring and/or control into existing Plant DCS.
Maintenance and Service Agreement available to extend parts and labor warranty to full 10 years for entire system.