A novel concept for a high energy and material efficient nitric acid production process and system is provided, wherein the nitric acid production process and system, particularly integrated with an ammonia production process and system, is configured to recover a high amount of energy out of the ammonia that it is consuming, particularly in the form of electricity, while maintaining a high nitric acid recovery in the conversion of ammonia to nitric acid. The energy recovery and electricity generation process comprises pressurizing a liquid gas, such as air, oxygen and/or N.sub.2, subsequently evaporating and heating the pressurized liquid gas, particularly using low grade waste heat generated in the production of nitric acid and/or ammonia, and subsequently expanding the evaporated pressurized liquid gas over a turbine. In particular, the generated electricity is at least partially used to power an electrolyzer to generate the hydrogen needed for the production of ammonia. The novel concepts set out in the present application are particularly useful in the production of nitric acid based on renewable energy sources.

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 O.sub.2 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.

A process and a plant for producing nitric acid involves oxidizing ammonia in the presence of catalysts to provide nitrogen monoxide-containing process gas in an oxidation reactor. The formed nitrogen monoxide may be supplied with oxygen-containing gas, and nitrogen monoxide is oxidized to provide nitrogen dioxide that is reacted with water in an absorption apparatus to give nitric acid, nitrous acid, and/or solutions of nitrates and/or nitrites. Oxidation of the nitrogen monoxide may be effected in an additional reactor positioned between the oxidation reactor and the absorption apparatus and traversed by the process gas. The oxidation of the nitrogen monoxide may be effected in an additional reactor parallel and connected to the absorption apparatus and traversed by the process gas. The disclosed processes and plants feature a high energy efficiency combined with a simple construction, and existing plants are easily upgradeable.

A process and a plant for producing nitric acid involves oxidizing ammonia in the presence of catalysts to provide nitrogen monoxide-containing process gas in an oxidation reactor. The formed nitrogen monoxide may be supplied with oxygen-containing gas, and nitrogen monoxide is oxidized to provide nitrogen dioxide that is reacted with water in an absorption apparatus to give nitric acid, nitrous acid, and/or solutions of nitrates and/or nitrites. Oxidation of the nitrogen monoxide may be effected in an additional reactor positioned between the oxidation reactor and the absorption apparatus and traversed by the process gas. The oxidation of the nitrogen monoxide may be effected in an additional reactor parallel and connected to the absorption apparatus and traversed by the process gas. The disclosed processes and plants feature a high energy efficiency combined with a simple construction, and existing plants are easily upgradeable.

Integrated process for the synthesis of ammonia and nitric acid, comprising a synthesis of nitric acid including the following steps: a) subjecting a stream of ammonia (10) to catalytic oxidation, obtaining a gaseous stream containing nitrogen oxides (13); b) subjecting said gaseous stream to a process of absorption of nitrogen oxides, providing nitric acid (16) and a tail gas (17) containing nitrogen and residual nitrogen oxides; c) subjecting at least a portion of said first tail gas (17) to a process of removal of nitrogen oxides, providing a nitrogen oxides-depleted tail gas (18), and comprising a synthesis of ammonia by catalytic conversion of a make-up gas (126, 226) comprising hydrogen and nitrogen in an ammonia synthesis loop, wherein at least a portion (18b, 18d, 21) of said second tail gas is used as nitrogen source for obtaining said make-up gas (126, 226).

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 O.sub.2 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.

Disclosed is a dual pressure plant for the production of nitric acid on the basis of the oxidation of ammonia. The plant comprises a reactor configured to produce a burner gas stream; a gas cooling section configured to form a cooled burner gas; a condensation section configured to form an aqueous nitric acid condensate and an uncondensed nitrogen oxides gas stream; an absorption section configured to produce raw nitric acid and a tail gas; and a tail gas treatment system configured to form a purified tail gas. In a tail gas heating section a further heat exchanger configured to receive heat from the burner gas stream, said further heat exchanger being positioned relatively close to the reactor.

Wire for weaving or knitting a catalyst gauze, said wire being characterized in that it is a stranded wire comprising an assembly of n intertwined filaments, n being an integer with 2n8, wherein each of said filaments comprises Pt or a Pt alloy constituted of at least 50% by 5 weight of Pt, said filaments being twisted together over their length so that each of the filaments is wound to at least one other filament.

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.

A dual-pressure plant for the synthesis of nitric acid comprising: a reactor (4) providing a gaseous effluent (15) containing nitrogen oxides; an absorption tower (6) nitrogen oxides react with water providing raw nitric acid and, said absorption tower operating at a pressure greater than the pressure of the reactor; a compressor (5) elevating the pressure of the reactor effluent (15) to the absorption pressure; said plant also comprising a first bleacher (37) and a second bleacher (7), said first bleacher (37) stripping with air (39) nitrogen oxides from the output stream (27) of the absorption tower (6) providing a partially stripped nitric acid stream (40) and a nitrogen oxides-loaded air stream (41), the former being fed to the second bleacher (7) and the latter being recycled to the delivery-side of said compressor (5).