NOx Emission Strategy: Optimizing Your SCR

NOx Emission Strategy: Optimizing Your SCR

The updated CSAPR rule is here. The final rule became effective on December 27, 2016.  The update requires some plants lower NOx emission standards during the compliance ozone season, starting in 2017.

What does this mean for operators of SCRs?   It may require operators to re-commission idled SCRs, increase utilization of older SCRs, eliminate by-pass dampers, and increase the use of consumables.  All of these yield higher operating costs.  This means operators of these units should be looking for low cost ways to achieve the higher performance required.

One the areas that can yield low cost improvements is through the optimization of the flue gas flow distribution to the SCR.  Specifically,

  • Re-modeling flow through the SCR to reflect current and future operating conditions may be necessary
  • To determine how the potential removal of SCR Bypasses would impact flow distribution.
  • Reducing or eliminating ash build up, increasing efficiency.
  • Evaluating different catalyst pitches, increasing catalyst life
  • Modifying LPA screen installation

Flue gas flow distribution optimization should be part of a holistic approach to identify and create strategies to implement the lowest cost (ie low capital AND low operating), highest performance solutions for SCRs.

The main focus is on lowering your NOx emissions, but there are adjacent opportunities in these efforts as well.  These can often be achieved with intentional planning, allowing you to capitalize on work that is already required.  Emphasis should not be lost on:

  • Improving load following (cycling) capabilities
  • Improving unit heat rate
  • Reducing variable operating costs such as ammonia or urea
  • Improving fly ash sales
  • Improving start up and ramping capabilities
  • Reducing SO3 emissions

View our consulting and support services to learn more about how we can help!

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