Process for minimizing pollutant concentrations in combustion gases
AssigneeNalco Fuel Tech
InventorsJogindar M. Chawla, Joachim von Bergman, deceased, Reinhard Pachaly
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Abstract
Distribution of pollution reducing agents within an effluent at the effective temperature window for effective gas phase reaction is greatly improved. A two-phase mixture having fine droplets of liquid, e.g. a NO.sub.x reducing agent such as aqueous solutions of urea or ammonia, dispersed in a gaseous component, such as air, is injected into the effluent an sonic velocity to achieve a distribution of particles of sizes effective to uniformly reduce NO.sub.x within the zone of effective temperature while not producing a significant level of droplets so large that they survive beyond the temperature zone.
Claims9
A process for reducing the concentration of NO.sub.x in a combustion effluent, the process comprising:
- preparing a two-phase NO.sub.x -reducing mixture containing liquid and gaseous components, said liquid component comprising a solution of urea;
- and
- injecting the NO.sub.x -reducing mixture at its characteristic sonic velocity into a passage containing a combustion effluent at a temperature effective for reduction of the NO.sub.x by selective gas-phase reaction,
- wherein the mixture is injected at liquid droplet sizes effective to enable evaporation prior to impingement on a surface within or defining said passage.
A process for reducing the concentration of NO.sub.x in a combustion effluent, the process comprising:
- preparing a two-phase NO.sub.x -reducing mixture containing liquid and gaseous components, said liquid component comprising a solution of one or more materials selected from the group consisting of ammonia, urea, ammonium citrate, ammonium formate, ammonium carbonate, ammonium hydroxide, and ammonium acetate, and said gaseous component comprises air, steam or a mixture of these;
- and
- injecting the NO.sub.x -reducing mixture at its characteristic sonic velocity into a passage containing a combustion effluent at a temperature effective for reduction of the NO.sub.x by selective gas-phase reaction,
- wherein the mixture is injected at liquid droplet sizes effective to enable evaporation prior to impingement on a surface within or defining said passage.
Dependencies are inferred from the claim text.