Project Synopsis

Calculate estimated hydrofluoric acid (HF) and nitric acid (HNO3) vapor emissions from a metals cleaning and etching operation.

Project Summary

EMISSIONS ESTIMATING FOR A METALS CLEANING AND ETCHING OPERATION

The client owns and operates a specialty metals manufacturing facility and contracted Process Engineering Associates, LLC (PROCESS) to provide process engineering assistance in estimating hydrofluoric acid (HF) and nitric acid (HNO3) emissions from a metals cleaning and etching operation.  Project tasks included:

  • Calculating the amount of HF and HNO3 released into the atmosphere from an acid dip tank during normal operation (metal cleaning) and during idle operation (no metal being cleaned) .
  • Calculating the amount of HF and HNO3 released to the atmosphere during an emergency dump (transfer) of the acid dip tank contents to an open top wastewater storage tank. 

PROCESS used its licensed commercial process simulation software, CHEMCAD, to determine the HF and HNO3 equilibrium vapor concentrations at the liquid surface of the acid dip tank and the wastewater storage tank.  The resultant mole fractions were used in subsequent mass transfer calculations (vapor diffusion and flux) to estimate the mass flow rates of each constituent generated from the open top tanks.  This information was used by the client in discussions with the state air permitting agency for modifications to existing air permits. 

Industry Type

  • Specialty Metals Manufacturing

Utilized Skills

  • Emissions estimating
  • Mass transfer calculations
  • Environmental compliance process engineering support

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