HRSG Cycling Solutions

HRSG Cycling Solutions

Combined cycle power plants have become a crucial component for maintaining electrical grid stability, in large part due to increasing renewable power capacity and changing market conditions. Renewable power sources routinely experience large swings in megawatt output that require combined cycle plants to rapidly ramp load in order to supply consistent power to the grid. However, rapid startups and extreme load cycling can exceed recommended HRSG limitations, leading to excessive life expenditure, premature equipment failure, and costly downtime.

Using our ProTRAX simulation system with computational fluid dynamics (CFD) and finite element analysis (FEA) software, TRAX can quantify potential HRSG component lifetime consumed when rapidly cycling load.

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TRAX can…

  • Analyze rapid load-swing HRSG component fatigue
  • Assess component end-of-life
  • Analyze the cost of cycling damage
  • Propose improvements for asset management
  • Make future planning recommendations for asset reliability


TRAX can help solve other problems related to thermal cycling, including:

  • Flue gas stratification areas that cause poor heat transfer, low efficiency, and increased heat rate
  • Flow conditions leading to tube vibrations, which weaken tubes and support structures
  • Evaporator tube bank conditions that cause uneven tube heating and departure from nucleate boiling
  • Inefficient SCR operation
  • Poor ammonia dispersion upstream of the SCR, leading to excessive ammonia use, ammonia slip, and insufficient NOx removal
  • Stack condensation

HRSG Cycling Solutions

January 3, 2020

TRAX has delivered a carbon capture simulator for a 150 MW coal-fired unit that models the capture of the full flue gas stream.  The system provides both CO2 and SO2 capture, delivering the captured CO2 to a pipeline for industrial use and underground storage.

TRAX Carbon Capture Model Included:

—CO2 and SO2 capture
—Sulfuric acid plant
—CO2 and SO2 amines filtration and purification
—CO2 compression
—CO2 pipeline and cavern

As shown below, TRAX built a modular simulation replicating the plant layout using our software, ProTRAX.  ProTRAX contains a full suite of modules specific to carbon capture functions and can model a wide variety of processes.  TRAX also virtually replicated the user interface that appears in the plant.  

Model Scope

ProTRAX is a modular software that can easily integrate multiple models for larger projects.


TRAX organizes the simulator model to match the layout of the site or process being modeled.


Depending on the Absorber module selected, the module can remove water vapor (H2O), carbon dioxide (CO2), and/or sulfur dioxide (SO2) from an air or gas stream.


Each ProTRAX module is backed by comprehensive documentation, including a general description, module inputs and outputs, and mathematical formulae.


The training value of a simulator occurs in the interactive screens that replicate the site equipment.

Upon initial delivery, the TRAX simulator was used to debug control logic and processes prior to site installation and to provide operations training prior to plant startup.  There was a clear need to begin training operators as early as possible since they had multiple unfamiliar systems to learn.

Thanks to the ProTRAX simulator, our customer gained considerable insight into control functionality and system interactions, resulting in modification to some control logic and correction of simple errors.  TRAX was able to assist with controls tuning, and helped in development of initial plant Operating Procedures.

The latest upgrade brings the model into alignment with the as-built plant condition by updating and tuning the simulator models to match the current plant dynamics. In addition, TRAX has updated the simulator controls and HMI graphics to the as-built state.  Keeping the simulator aligned with the current plant condition is critical to maintaining a positive training value, and is of paramount importance to the customer.