Patent ID: 8147784
Filing Date: 2012-04-03
Classification: B01D

Abstract:
1. A process for the combined removal of both ammonia in one or more ammonia-containing waste gas flows and nitrogen oxides in one or more additional nitrogen oxide-containing waste gas flows in a combined ammonia/urea synthesis plant, comprising selective non-catalytic reduction in a temperature range from 850° C. to 1100°, by which nitrogen oxide reduction rates of up to 80% are achieved, or selective catalytic reduction in a temperature range from 150° C. to 550° C., by which nitrogen oxide reduction rates of up to 99% are achieved, in which the ammonia and the nitrogen oxides react with one another to give nitrogen and water, wherein an ammonia-containing waste gas flow from at least one of a low-pressure absorber or an atmospheric absorber of the urea synthesis plant is mixed with the nitrogen oxide-containing waste gas flow of a flue gas duct of a primary reformer of the ammonia synthesis plant and is submitted to a selective non-catalytic reduction or a selective catalytic reduction depending on the temperature of the mixture and depending on the nitrogen oxide reduction rate to be reached, both the ammonia and the nitrogen oxides of the mixed waste gas flows being depleted simultaneously during the same process step.