Both ramp rate and minimum load are parameters which are being pushed to – and beyond – many older plants’ original design basis, by current market forces.  A plant’s ability to extend its operating range in these areas can potentially improve its dispatch and profitability, but such improvements may require specific changes to mitigate increased maintenance costs and accelerated damage to certain components.   This presentation touches on several aspects of this new operating challenge for existing boilers and emissions controls:

1.       Cycling and load ramping:  Typical capabilities of various boiler design types are reviewed, and the effects of increased load cycling are discussed.  One area of focused review is the thick-walled pressure parts of the boiler, and the need to now consider cyclic fatigue in addition to the long-term stresses and operating history of the boiler and its components.

2.       Reduced minimum load:  In some regions, the inopportune timing of power supply from solar and wind resources not only leads to faster ramp rate requirements of on-demand power plants, but also results in a new daytime period of reduced load demand.  Load turndown is limited by several factors for coal-fired utility boilers and depends on the specific design and equipment at each plant.  Often, maintenance of conditions required for emissions controls will be one of the first items to address when considering a reduction from present minimum load for a plant.

3.       Potential improvements and design features of boilers are described, with the aim of allowing faster ramping and/or reduced minimum loads.


Boiler & Aqcs Load Cycling and Low Load Operation

Division / Sponsors: 
Power Division & Nuclear Engineering Division (NED)

Power Conference
Paper Proceedings: https://asmedigitalcollection.asme.org/POWER/POWER2020/volume/83747

International Conference on Nuclear Engineering
Paper Proceedings: https://asmedigitalcollection.asme.org/ICONE/ICONE2020/volume/83761

POWER-ICONE - Virtual Conference

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