May 24, 2007

NO_x Reagent Utilization Important from Cost, Efficiency, and Maintenance Perspective

 The Hot Topic Hour on May 24 was devoted to maximizing the performance and minimizing the maintenance of a NO_x Control system. Dynamic classifiers, optimization software, monitoring techniques, and static mixers were all discussed as ways to improve utilization. The recorded Hot Topic is available for viewing at  

You can also view the power point presentations in the NO_x Decision Tree through the following links.

Continuing Decision Process For: Products

Presented at May 24, 2007 Hot Topic Hour by Cal Lockert

On-Line Ammonium Bisulfate Measurement

http://www.mcilvainecompany.com/NOx_Decision_Tree/subscriber/Tree/DescriptionTextLinks/Cal Lockert Breen Energy Solutions Hot Topic May 24.htm

Cal said that the problem in fouling is not ammonia slip but the formation of ammonium bisulfate (ABS). Using a real time ABS feedback signal can:

1. Maximize reagent injection rate regardless of flue gas SO₃ level,
2. Maximize reagent injection rate regardless of load or flue gas temperature,
3. Eliminate air heater ABS fouling,
4. Eliminate air heater H₂SO₄ fouling in non-NO_x season,
5. Eliminate unnecessary heat rate penalties due to arbitrarily high air heater outlet temperatures.

Continuing Decision Process For: Products

Presentation at May 24, 2007 Hot Topic Hour by Mike Moxley

Company History and Products

http://www.mcilvainecompany.com/NOx_Decision_Tree/subscriber/Tree/DescriptionTextLinks/M. Moxley - Sulzer McIlvane Report pt 1.pdf
 

Mixing and Reaction Technology

http://www.mcilvainecompany.com/NOx_Decision_Tree/subscriber/Tree/DescriptionTextLinks/Mike Moxley McIlvane Sulzer Report pt 2.pdf

Sulzer has sold more than 50 of its static mixer systems for DeNO_x in the U.S.

The Sulzer SMV mixing system provides both macromixing and micromixing and has the following features.

• Mixes across entire duct cross section for macromixing
• Large cross flow to distribute localized concentration
• High NO_x and low NO_x mixed from one side to the other
• High temperature and low temperature mixing
• Mixes locally for micromixing
• Intense eddies mix in the element
• Eddies continue in open space after the mixer
• Introduction of NH₃ across entire duct with flue gas

Continuing Decision Process For: Products

Presentation at May 24, 2007 Hot Topic Hour by Robert Sommerlad

Dynamic Classifiers for Reagent Utilization for NOx Control? …Yes, Indeed

http://www.mcilvainecompany.com/NOx_Decision_Tree/subscriber/Tree/DescriptionTextLinks/R. Sommerlad - Loesche Hot Topic May 24.htm

Dynamic Classifiers can increase fineness and decrease coarse particles leading to

• Better burnout (lower Unburned Carbon)
• Reduced slagging and fouling
• Reduced excess air resulting in
  • Increased boiler efficiency
  • Decrease in emissions – NO_x, CO

   

Continuing Decision Process For: Products

Gas Mixing Applied to SCR Systems

http://www.netl.doe.gov/publications/proceedings/03/scr-sncr/Final_Naqvi.pdf
 

Presentation at May 24, 2007 Hot Topic Hour by Stefan Lesser

Delta Wing SCR Technology

http://www.mcilvainecompany.com/NOx_Decision_Tree/subscriber/Tree/DescriptionTextLinks/Stefan Leser Balcke Durr - Delta Wing Hot Topic.pdf

Balcke Dürr has developed an injection system in combination with swirl induced mixers (Delta Wing) to improve SCR performance and to overcome the disadvantages of ammonia injection grids.

• The system induces standing vortices independent of the mixing ratio of the partial flows; therefore it does not have to be adjusted to changing boiler operating conditions.
• The induced vortices mix the partial flows very effectively within a very short distance; this provides greater flexibility in the design of SCR retrofit units.
• Mixing is effected with high efficiency and a minimum of pressure drop; NH₃ / NO_x distribution values at the inlet to the 1^st catalyst layer of less than ± 3 percent of the mean value can be achieved. These values for mole ratio distribution also lower the risk of ammonia slip and the formation of ammonia bisulfates (ABS).
• The ammonia is injected through only a few nozzles of large diameters that extend only a very short length into the upstream duct. There is no risk of dust blockages and wear.
• The ammonia is injected in a swirl system which allows injecting aqueous ammonia (NH₄OH) directly in the flue gas without pre-evaporation in high-dust SCR applications. All other types of ammonia can be used such as anhydrous NH₃, ammonia from urea, and pre-evaporated aqueous ammonia.
• As the mixing quality is independent of the boiler load, the need for extensive tuning during commissioning and therefore the time for the SCR starts up will be minimized.

Continuing Decision Process For: Products

Presentation at May 24, 2007 Hot Topic Hour by Peter Spinney

NeuCo Optimization Solutions for Improving SCR Performance

http://www.mcilvainecompany.com/NOx_Decision_Tree/subscriber/Tree/DescriptionTextLinks/NeuCo Mcllvaine 5-24-07.htm

• An Optimizer must :

            - Continuously identify actions that can improve asset performance,

            - Quantify the benefits and missed opportunities and

            - Inform users about what actions were taken and why.

• CombustionOpt:

            - Provides real-time closed-loop optimization of fuel and air mixing plus temperature by manipulating
               all relevant fuel and air injection points.

            - Uses Neural networks model predictive control technologies, and heuristics.

            - Benefits include:

• Boiler NO_x reduction of 10-20 percent;

• NH₃ reduction of 15-25 percent;

• Optimal monetized tradeoffs (NO_x, NH₃, fuel cost);

• Heat rate improvement of 0.25-2.0 percent;

• Improved steam temperature control;

• Overcoming stratification, fan and mill constraints;

• Prevention of slag formation; and

• Improved control of opacity.

• SootOpt provides real-time closed-loop optimization of unit performance by manipulating all relevant sootblowing controls.
   

• Conclusions:

            - Even well-designed and operated SCRs are susceptible to inherent stratification of
              combustion gases and NO_x;

            - Manual SCR tuning is necessary but can degrade rapidly as boiler and operating
              conditions change;

            - NH₃ reductions are the result of not only lower boiler NOx, but a boiler outlet NO_x
               profile optimally exploiting relative catalyst effectiveness; and

            - Integrated optimization of combustion and boiler cleaning maximizes SCR/reagent-related
              benefits.

Continuing Decision Process For: Catalyst Replacement

Presentation at May 24, 2007 Hot Topic Hour by James Staudt, Andover

SCR Catalyst Management

http://www.mcilvainecompany.com/NOx_Decision_Tree/subscriber/Tree/DescriptionTextLinks/Andover CAT MANAGER_McIlvaine.pps

Cat Manager provides a program to help utilities make decisions about catalyst replacement. It takes into account NO_x removal efficiency, ammonia slip, pressure drop and other parameters including the choice of catalyst cleaning vs. new catalyst.