NEWS RELEASE                                                                            DECEMBER 2012 

Most of the Dollars but Only 50 Percent of the Projects are Selecting SCR over SNCR and Other NOx Removal Techniques 

Expenditures for equipment and consumables to reduce NOx will exceed $6 billion per year over the next five years. This is the latest forecast in NOx Control World Markets published by the McIlvaine Company.

Selective Catalytic Reduction (SCR) systems require large capital investments. However, the consumables (catalyst and ammonia) are less than the alternatives. Selective non-catalytic reduction (SNCR) relies on injecting urea in the hot zone of a furnace or boiler. The capital cost is low but the amount of reagent per ton of NOx removed is high. Hydrogen peroxide is another alternative which does not require a significant capital investment, but does require consumption of a relatively expensive chemical.

One technology which requires only modest capital investment is ozone injection. If a downstream scrubber is already in place, then the resultant NO2 is captured before it can exit the stack. The disadvantage of this process is the high energy cost to create the ozone. The advantage is that it can be coupled with conventional SCR to provide a combined efficiency in excess of 95 percent. Hydrogen peroxide can also be used in this manner.

McIlvaine predicts that the driving force for NOx control investment in the U.S. will ultimately be the ambient fine particulate standards. These standards will force individual states to emulate the Los Angeles example and look for reductions at any major source regardless of how efficient the existing technology may be. A big power plant which is removing 90 percent of the NOx may still be emitting 2000 tons per year. This quantity equals all the emissions of 200 small boilers which on an uncontrolled basis emit 10 tons per year each. It will be both politically expedient and cost effective to require the power plant to increase its efficiency to 98 percent before it considers controls for the small boilers.

McIlvaine therefore predicts that combination SCR and chemical injection systems will be one of the main tools to address the fine particulate standards. In the western U.S., nitrates comprise the majority of the fine particles. The easiest way to eliminate them is to eliminate the NOx which creates them.

China will exceed the U.S. in NOx control investment over the next five years. It will install SCR on more than 100,000 MW of coal-fired power plants per year. China will also be fitting a number of industrial sources with SNCR systems. There are numerous waste incinerators and cement plants around the world fitted with SNCR systems.

This forecast does not include mobile sources which are addressed in another McIlvaine report.

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