Abstract: A system suitable for oxidizing ammonia with oxygen in the presence of catalysts is described. The system includes a reactor equipped with at least one supply line for a reactant gas mixture and at least one discharge line for a process gas; a catalyst comprising at least one transition metal oxide that is not an oxide of a platinum metal; and a device for adjusting a molar ratio of oxygen to ammonia of less than or equal to 1.75 mol/mol in the reactant gas mixture by mixing an oxygen-containing gas stream having an O2 content of <20% by volume with a chosen amount of ammonia. The oxygen-containing gas stream is produced by a device for: diluting an air stream with a gas stream comprising less than 20% by volume oxygen; or depleting oxygen from an oxygen-containing gas mixture, preferably from air; or by a combination thereof.

Abstract: An apparatus is provided for treatment of process gas formed during nitric acid production by catalytic oxidation of NH3. The apparatus includes a reactor, a first catalyst bed for N2O decomposition, an absorption tower to react the NOx formed with an absorption medium downstream of the first catalyst bed, a device for adding NH3 added to tailgas entering the second catalyst bed, and a second catalyst bed for NOx reduction and further decrease in N2O in the tailgas exiting the absorption tower. The second catalyst bed contains at least one iron-loaded zeolite catalyst. N2O removal in the first catalyst bed is limited such that the process gas exiting the first catalyst bed exhibits a N2O content of >100 ppmv and a molar N2O/NOx ratio of >0.25. Treated gas exiting the second catalyst bed has a NOx concentration of <40 ppmv and a N2O concentration of <200 ppmv.

Abstract: A method for disposing a bed comprising particles in a burner through which a gas can flow, more particularly in a burner basket of an ammonia oxidation burner, where the particles are disposed such that the bed has a greater flow resistance in an edge region of the burner than in an inner region of the burner. Further, a burner basket for a burner may have a bed comprising particles, wherein the particles are disposed such that the bed has a greater flow resistance in an edge region of the burner basket than in an inner region of the burner basket.

Abstract: A system suitable for oxidizing ammonia with oxygen in the presence of catalysts is described. The system includes a reactor equipped with at least one supply line for a reactant gas mixture and at least one discharge line for a process gas; a catalyst comprising at least one transition metal oxide that is not an oxide of a platinum metal; and a device for adjusting a molar ratio of oxygen to ammonia of less than or equal to 1.75 mol/mol in the reactant gas mixture by mixing an oxygen-containing gas stream having an O2 content of <20% by volume with a chosen amount of ammonia. The oxygen-containing gas stream is produced by a device for: diluting an air stream with a gas stream comprising less than 20% by volume oxygen; or depleting oxygen from an oxygen-containing gas mixture, preferably from air; or by a combination thereof.

Abstract: A system suitable for oxidizing ammonia with oxygen in the presence of catalysts is described. The system includes a reactor equipped with at least one supply line for a reactant gas mixture and at least one discharge line for a process gas; a catalyst comprising at least one transition metal oxide that is not an oxide of a platinum metal; and a device for adjusting a molar ratio of oxygen to ammonia of less than or equal to 1.75 mol/mol in the reactant gas mixture by mixing an oxygen-containing gas stream having an O2 content of <20% by volume with a chosen amount of ammonia. The oxygen-containing gas stream is produced by a device for: diluting an air stream with a gas stream comprising less than 20% by volume oxygen; or depleting oxygen from an oxygen-containing gas mixture, preferably from air; or by a combination thereof.

Abstract: A burner basket for an ammonia oxidation burner includes a gas-permeable bottom plate, with a side wall that is spaced apart from the bottom plate by a gap, and a retaining device covering the bottom plate and the gap for retaining particles of a bulk material that can be arranged in the burner basket. A fastening element is arranged on the bottom plate, by which the retaining device is fixed in place. An ammonia oxidation burner comprises a burner for oxidizing ammonia and a burner basket.

Abstract: A process and a plant for decreasing the concentration of NOx nitrogen oxides in the residual gas in the preparation of nitric acid, where the temperature of the residual gas is regulated by means of a temperature regulating apparatus during shutdown and/or start-up of the plant, with the residual gas being conveyed in a circuit and here flowing through the temperature regulating apparatus and the residual gas purification plant so that colorless shutdown and/or start-up of the plant is made possible.

Abstract: A method for disposing a bed comprising particles in a burner through which a gas can flow, more particularly in a burner basket of an ammonia oxidation burner, where the particles are disposed such that the bed has a greater flow resistance in an edge region of the burner than in an inner region of the burner. Further, a burner basket for a burner may have a bed comprising particles, wherein the particles are disposed such that the bed has a greater flow resistance in an edge region of the burner basket than in an inner region of the burner basket.

Abstract: The invention relates to a process and apparatus for preparing nitric acid by catalytic oxidation of NH3 by means of oxygen and subsequent reaction of the NOx formed with an absorption medium in an absorption tower, which comprises a catalyst bed for N2O decomposition arranged in the process gas downstream of the catalytic NH3 oxidation and upstream of the absorption tower in the flow direction and a catalyst bed for NOx reduction and effecting a further decrease in the amount of N2O arranged in the tailgas downstream of the absorption tower in the flow direction, wherein the amount of N2O removed in the catalyst bed for N2O removal arranged in the process gas is not more than that which results in an N2O content of >100 ppmv and a molar N2O/NOx ratio of >0.

Abstract: A burner basket for an ammonia oxidation burner includes a gas-permeable bottom plate, with a side wall that is spaced apart from the bottom plate by a gap, and a retaining device covering the bottom plate and the gap for retaining particles of a bulk material that can be arranged in the burner basket. A fastening element is arranged on the bottom plate, by which the retaining device is fixed in place. An ammonia oxidation burner comprises a burner for oxidizing ammonia and a burner basket.

Abstract: The invention relates to a process and apparatus for preparing nitric acid by catalytic oxidation of NH3 by means of oxygen and subsequent reaction of the NOx formed with an absorption medium in an absorption tower, which comprises a catalyst bed for N2O decomposition arranged in the process gas downstream of the catalytic NH3 oxidation and upstream of the absorption tower in the flow direction and a catalyst bed for NOx reduction and effecting a further decrease in the amount of N2O arranged in the tailgas downstream of the absorption tower in the flow direction, wherein the amount of N2O removed in the catalyst bed for N2O removal arranged in the process gas is not more than that which results in an N2O content of >100 ppmv and a molar N2O/NOx ratio of >0.

Abstract: A system suitable for oxidizing ammonia with oxygen in the presence of catalysts is described. The system includes a reactor equipped with at least one supply line for a reactant gas mixture and at least one discharge line for a process gas; a catalyst comprising at least one transition metal oxide that is not an oxide of a platinum metal; and a device for adjusting a molar ratio of oxygen to ammonia of less than or equal to 1.75 mol/mol in the reactant gas mixture by mixing an oxygen-containing gas stream having an O2 content of <20% by volume with a chosen amount of ammonia. The oxygen-containing gas stream is produced by a device for: diluting an air stream with a gas stream comprising less than 20% by volume oxygen; or depleting oxygen from an oxygen-containing gas mixture, preferably from air; or by a combination thereof.

Abstract: The invention relates to a process and apparatus for preparing nitric acid by catalytic oxidation of NH3 by means of oxygen and subsequent reaction of the NOx formed with an absorption medium in an absorption tower, which comprises a catalyst bed for N2O decomposition arranged in the process gas downstream of the catalytic NH3 oxidation and upstream of the absorption tower in the flow direction and a catalyst bed for NOx reduction and effecting a further decrease in the amount of N2O arranged in the tailgas downstream of the absorption tower in the flow direction, wherein the amount of N2O removed in the catalyst bed for N2O removal arranged in the process gas is not more than that which results in an N2O content of >100 ppmv and a molar N2O/NOx ratio of >0.