Method for so.sub.x /no.sub.x pollution control

Abstract

SO.sub.x /NO.sub.x pollution control process comprising injecting into flue gas from 1 to 50% carbon (preferably 5-15%) along with a dry, finely divided sodium sorbent, preferably sodium bicarbonate or Nahcolite, a naturally occurring form of sodium bicarbonate. The process removes both SO.sub.x and NO.sub.x from the flue gases of utility and industrial plants, incinerators and the like by dry injection into a flue gas duct a sufficient distance upstream of a particulate collection device, such as an ESP or baghouse, to collect spent reagent and additive. The sodium reagent reacts with the SO.sub.2 to form sodium sulfate and also removes NO.sub.x in the form to NO. The carbon additive reacts with NO.sub.2 to reduce the concentration of the NO.sub.2 in the exit flue gases to below the NO.sub.2 brown plume visibility threshold (about 30 ppm NO.sub.2, not corrected to 0% O.sub.2, depending on stack diameter and ambient conditions). The additive may be used alone or in conjunction with other adjuvants or additive such as urea or ammonia. The carbon must have a high effective surface area to be active is suppressing NO to NO.sub.2 conversion, and is preferably present in, on, in association with, or mixed with, an inert carrier, such as fly ash. Preferably, the 'C factor', which is the product of the fraction of carbon in the additive times the effective surface area of the carbon in the additive, is above 1.