I work with NH3 and SO3 Flue Gas Conditioning Systems (for ESP tungin) and I agree the excess NH3 and SO3 will cause the blue plume. Additonaly Many Coal fired boilers that have added SCRs have to now closely monitor their NH3 slip. Additionly, the SCR catalysts may be converting SO2 in the...
You mentioned you thoguht you had some SO2 venting. (caused by burning of sulfur due to ignition of the iron?) You don't think your "smoldering" is an ongoing fire?
IF you add more air creating a positive air purging system won't this add Oxygen to the fire?
I'm curious to see is...