Project Synopsis

Evaluate an existing SCR NOx scrubber for use in a new metal washcoat calcining process at a catalytic device manufacturing facility.

Project Summary


The client owns and operates a U.S. facility that manufactures catalytic inserts for automotive and industrial emission control applications.  The catalyst-containing slurries (washcoat) are batched at the facility and transferred to catalyst substrate coating production lines. The production lines include a final drying and calcining step in which the slurry washcoat, containing aluminum oxide, rare earth oxides, and precious metals, is fixed to a substrate and passed through a dryer and a high temperature (calcining) oven.  The production lines are equipped with pollution control systems for abatement of the nitrous oxides (NOx). The major unit operations in the pollution control system include a selective catalytic reduction (SCR) unit that uses ammonia injection to react with the NOx, and an ammonia scrubber to absorb ammonia carryover from the SCR.

The client contracted with Process Engineering Associates, LLC (PROCESS) to review a new Vanadium washcoat chemistry that was to be used at the facility for the purpose of defining potential issues related to operating the existing wet scrubber.

Specific project tasks included:

  • Review the chemistry of new washcoat to look for possible negative side reactions in the NOx scrubber.
  • Review client-supplied data and details from several small-scale trial runs of the new Vanadium-containing washcoat.
  • Prepare a report summarizing the review of the scrubber chemistry including recommendations to address operational problems observed during the trials.  These problems included pH excursions in the scrubber (high), unpleasant amine odors in the production area and a “purple haze” in the scrubber area.  PROCESS’ recommended changes to the scrubber during the first production run of the Vanadium washcoat prevented the problems observed during the trail runs.

Industry Type

  • Metal Catalyst Manufacturing

Utilized Skills

  • Scrubber design
  • Process evaluation
  • Process troubleshooting

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