DeNOx Routes compared in Hot Topic Hour Yesterday (March 24)

Some 50 people, from A/Es, utilities and DeNOx supplier companies participated in a discussion of the options for NO_x reduction in coal, cement, incineration, refining, and mobile. Here are some takeaways.

• DeNOx has to be considered as one of multiple pollutants for which a coordinated removal strategy is essential.
• Cross pollination among industries provides the ozone insights of refineries, the catalytic filter insights from glass furnaces, VOC and NO_x reduction from gas turbines and the catalyst management insights from coal-firing.
• Heat recovery with improvements in efficiency and reduction in greenhouses gases is a big potential with catalytic filtration.
• The replacement of precipitators with catalytic filters creates a huge market opportunity.
• Light duty diesel vehicles and in particular those manufactured by Volkswagen are likely to be retrofitted with billions of dollars of SCR systems.
• Coal: Hybrid SNCR/SCR systems, catalyst management plans which take into account mercury oxidation efficiency, and the complexity of local rules relative to ambient NO₂, ozone and particulate were discussed. Regulatory changes in the EU and the impact of local rules in China were also reviewed.
• Chemicals:  The potential for ozone NO_x oxidation in conjunction with wet scrubbers is significant. Hydrogen peroxide can be a trim addition to supplement other DeNOx technologies.
• Catalytic Filtration:  Much of the discussion was centered on the progress of catalytic filters and the manner in which they could be retrofitted into existing coal-fired power plants where there is a need for improved particulate control as well the need for NO_x and SO₂ reduction. The cost of shoehorning three pieces of big equipment into a space as opposed to raising the height of the present precipitator shell and installing two decks of catalytic filters is quite high. Running ductwork back and forth when not enough space is available around the boiler can add an expenditure as high as $100/kw. 
• Mercury:  The most recent generation of catalysts contributes greatly to mercury oxidation. 
• System Components:  U2A is surprisingly popular in China. Anhydrous ammonia is still the most cost-effective option but does involve safety risks.
• Cement:  SCR is making in-roads. There are successes in the U.S. and Europe. Scheuch has success with a semi dust SCR system. A hot precipitator reduces the dust load sufficiently to ensure long life of the catalyst.  A downstream baghouse removes remaining dust. If this approach is successful for cement could it also be a winner in certain coal-fired power plants?
• Incineration:  Backend SCR may not be any better for the environment than SNCR. The tradeoff is NO_x vs. CO₂. A Wall St. Journal article entitled “Dirty Little Secret” warned against putting too much weight on greenhouse gas reduction at the expense of ozone, VOC and particulate increases.  The article blames a severe smog problem in European cities on the push to diesel automobiles where decreased CO₂ is more than offset by emissions of other pollutants.
• W.L. Gore has a unique approach with catalytic filters for NO_x removal.  It can also supply another media (Remedia) for simultaneous particulate and dioxin removal.
• Refinery:  LoTOx and scrubbers are used at 30 refineries for NO_x reduction. Some reduction is also achieved by adding granular NO_x catalyst in the FCC.  McIlvaine posed the question as to whether the third stage cyclone could be replaced with a catalytic filter.  Insights on this are sought and will be appreciated.
• Mobile:  Stationary NO_x product suppliers, such as Johnson Matthey and Yara, are equally involved in the mobile sector where chaos may be the best descriptor. VW is facing adding SCR and urea tanks to 11 million automobiles. The heavy duty truck market is booming and off-road vehicles are now being required to install the equipment.  Power plant pump suppliers, such as Flowserve, are benefiting from the widespread scope of the rules.  They are supplying pumps to farmers who have storage tanks filled with a urea/water mixture and must dispense small quantities to various farm machinery

§  Gas Turbine:  Improved catalyst designs deal with NO_x, CO and VOCs. The Cormetech Meteor product was reviewed.

The entire discussion was recorded and can be viewed at NOx Control     85 minutes

 You can just review the power points at NOx Control Slides

There will be permanent access for suppliers in the following locations:

59EI Gas Turbine and Combined Cycle Supplier Program

N035 NOx Control World Market

N032 Industrial Air Plants and Projects

42EI Utility Tracking System

Diesel SCR (not linked)

Access is also provided in services which are free of charge to utilities but by subscription to others.

44I Power Plant Air Quality Decisions 

59D Gas Turbine and Combined Cycle Decisions

3ABC FGD and DeNOx Knowledge Systems