TRAX has found that using ProTRAX in combination with ANSYS Fluent® Computational Fluid Dynamics (CFD) software makes even more detailed analysis of process behavior possible. In this hybrid approach, TRAX assembles a CFD model to evaluate steady-state flow patterns and pressure drops. These values are used in a ProTRAX model to evaluate design pressures. CFD analysis of new equipment provides the in-depth operational data that can be used with ProTRAX models to simulate system-wide operations, which allows for detailed analysis of control strategies and expected system performance.

Diagnosing problems and inefficiencies in existing equipment is also possible using CFD analysis. Starting with a detailed 3D representation of a piece of equipment, TRAX can carry out tests at different operating conditions to determine the cause of the observed deficiency. Once the cause of the deficiency is identified, the 3D model can be altered to test potential fixes for the problem. This prevents costly equipment down time required to develop and physically test different equipment designs in order to eliminate the deficiency.

The Case for CFD

CFD analysis is used for a wide range of applications in industry. One TRAX client recently installed a flue gas desulfurization unit and needed to install a bypass duct around the scrubber due to operational issues. The bypass duct design was complicated by several factors:

  • Physical space restrictions limited the size and configuration of the duct
  • During a trip of the scrubber, furnace pressures had to remain negative
  • The required placement of the bypass damper and duct breachings created complex flow behavior that precluded the use of simple duct sizing calculations

TRAX used CFD modeling to address these issues:

  • Piping and ductwork - the flow of liquids, gasses, or two-phase mixtures can be modeled in detail to determine flow behavior in complex geometries that cannot be quantified using normal hand calculations. Areas of high or low pressure and bottlenecks can be easily identified and corrected. Piping designs with a high propensity for erosion can also be predicted and TRAX can design mitigating measures to reduce these effects.
  • Chemical processes - the distribution of reactants and fuel combustion can be modeled to allow for optimization of combustion and prediction of pollutant formation. Mixing vessels can also be modeled to ensure uniform mixing of reactants. CFD analysis can be used to refine the spray distribution of reactants for even application of chemicals to complex surfaces or parts. 3D temperature distribution can be calculated to locate areas of inefficient heat transfer and test possible improvements.

Maintaining electrical grid stability, especially in partnership with renewable power sources that routinely experience large swings in megawatt output, requires that plants rapidly ramp load.  However, rapid startups and extreme load cycling can exceed recommended equipment limitations, leading to excessive life expenditure, premature equipment failure, and costly down-time.

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

Analyze rapid load-swing component fatigue

Assess component end-of-life

Analyze the cost of cycling damage

Propose improvements for asset management

Future planning recommendations for asset reliability

Other Benefits

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 equipment vibration,

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