Project Synopsis

Provide process engineering assistance to a manufacturing facility in balancing the pressure profile in a large vent system associated with a pollution control system.

Project Summary


The client owns and operates a facility that manufactures catalytic inserts for automotive and industrial emission control applications.  The production lines are equipped with air pollution control systems for abatement of constituents generated in the process.  The client contracted with Process Engineering Associates, LLC (PROCESS) to assist them in balancing the pressure profile in a large vent system associated with one specific area of operation.  The vent system consists of approximately 15 – 20 process sources exhausting into a series of headers that feed one common header directed to a pollution control system (PCS).  The PCS consists of a heat exchanger, reheater, selective catalytic reduction system (SCR), ammonia scrubber, induced draft (ID) fan, and stack.  The process sources exhaust to the vent header on a semi-continuous basis and the sources are randomly operated.

The system configuration had been changed since the original design (new sources added, some sources removed) and the client was experiencing difficulty balancing air flows.  In addition, the ID fan was currently operated with an inlet damper to control the system static pressure and a significant amount of fresh air had to be brought into the system to maintain a reasonable damper position (>10% open).

The client contracted with PROCESS to evaluate the system and provide options for balancing the pressure profile.  Specific project tasks included the following:

  • PROCESS collected all applicable PCS data governing operation of the system which included field measurements of all ductwork (diameters, lengths, fittings etc.), equipment specifications, and system operating procedures.  Using this information, a computer process simulation of the system was generated using PROCESS‘ licensed commercial computer process simulation software, CHEMCAD.  The simulation provided a model that, to the extent practical, matched the performance of the existing system in terms of pressure drops, flow rates, and velocities.   Using the model, PROCESS was able to identify specific issues associated with the system configuration and operation.
  • Using the model, PROCESS was able to recommend three (3) specific options for balancing the system pressure profile: (1) changing ductwork sizes in certain locations – increasing in one of the headers and decreasing in two other headers, (2) installing a booster fan in one of the restricted headers, and (3) installing orifice plates or blast gates in two headers.  For all three options, PROCESS specified the required ductwork sizes, booster fan specification (Option 2 only), orifice plate sizes (Option 3 only), and PCS inlet draft pressure as required to achieve a balanced system.
  • PROCESS provided a system operating curve for all three options as well as an estimate of fan horsepower (HP) requirements.  The client used this information to specify a new ID fan with a variable frequency drive (VFD).  The required system turndown ratio (5:1) was higher than could be provided with a just a VFD so the client installed a fan with a VFD/damper combination.  Fan size/HP was reduced by almost 50%.

Industry Type

  • Catalyst Manufacturing

Utilized Skills

  • Vent and pollution control system modeling
  • Vent and pollution control system troubleshooting

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