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Combination Technologies 

NOX Removal Approaching that of SCR at a fraction of the cost, using a combination of SNCR and combustion modifications.

If your facility is required to achieve greater than 60% NOX reduction, consider a Combination of Technologies for the job.  At the USDOE - NETL 2001 Conference on SCR and SNCR, several exciting papers were presented which indicates that very high NOX removal can be achieved without committing to expensive SCR systems.  Depending upon your particular boiler configuration, you can combine SNCR with one or more of the following:

At Conectiv's 138 MW cyclone fired B.L.England 1, the addition of overfire air reduced uncontrolled emissions from 1.2 lb/MMBTU to 0.55 lb/MMBTU.  The injection of urea in the lower furnace ( 2400 - 3000F in the absence of oxygen ) got them down to 0.40 lb/MMBTU, and the subsequent application of traditional SNCR  got them as low as 0.23 lb/MMBTU.  The presenter at the conference went so far as to suggest that the technology appears capable of achieving up to 90% reduction with NO SLIP.  See:

 http://www.netl.doe.gov/publications/proceedings/01/scr/cremer1.pdf

At Asheville Unit No 1, Carolina Power & Light has installed low-NOX burners without overfire air, natural gas injection( replacing 3-10% of coal with gas) concurrant with urea injection, and traditional SNCR.  The net result has the unit running at 0.28 lb/MMBTU with ammonia slip below 5 ppm.  See:

http://www.netl.doe.gov/publications/proceedings/01/scr/boyle.pdf

These developments, in combination with NOX allowances and credits, provide large EGU's an option other than SCR to achieve their CAA obligations.