Nitric acid production

Ammonia and nitric acid are the two basic ingredients in the manufacture of ammonium nitrate. In addition to consuming ammonia directly, the manufacture of ammonium nitrate consumes ammonia by way of nitric acid production. The largest single use of nitric acid is that of ammonium nitrate production (see Ammonium compounds). Urea (qv) is manufactured by reacting ammonia and carbon dioxide. Urea manufacturing faciHties are often located close to ammonia plants. 

As of 1996 world production of sodium nitrate was about 520,000 metric tons annually. Of this quantity, some 450,000 t (86%) are produced in Chile from natural deposits by SQM Nitratos and distributed worldwide by several affOiates, eg, Chilean Nitrate Corporation in the United States and Nitrate Sales International in Belgium. The remainder, ca 70,000 t, is manufactured mainly in Europe, Japan, and Russia, generally as a by-product of nitric acid production. Additionally, China is known to manufacture some unknown but significant volumes of sodium nitrate for domestic use. 

Figure 4-25. Nitric acid plant at Fredericia (Denmark) with a four-machine turbogroup and generator. Power output to district heating system = 0-27 MW Power output to electric grid = 0-5.8 MW Steam turbine = 10.8 MW Axial compressor = 8.2 MW Centrifugal compressor = 4.1 MW Expander = 7.4 MW Nitric acid production = 650 t/d.

The 17% ferritic steels are easier to fabricate than the martensitic grades. They are used extensively in equipment for nitric acid production. The oxygen- and sulfur-resistant 30% chromium steel can be used at temperatures up to 1150°C but only for lightly loaded and well-supported furnace items because of its poor creep and brittlement properties when equipment is down to ambient temperatures [18]. 

For this reason, operation around atmospheric pressures is typical. Space velocity should he high to avoid the reaction of ammonia with oxygen on the reactor walls, which produces nitrogen and water, and results in lower conversions. The concentration of ammonia must he kept helow the inflammahility limit of the feed gas mixture to avoid explosion. Optimum nitric acid production was found to he obtained at approximately 900°C and atmospheric pressure. 

NH3. Ammonia is a colorless gas. It is a strong base, forms hydrogen bonds, is soluble in water, and is a fairly reactive molecule. Each year 12.4 million metric tons are manufactured by the Haber process (N2 + 3H2 2NH3 at 400°C and 250 atm), principally for nitric acid production, which is then used to make fertilizers and explosives. As a fertilizer, ammonia can be utilized in three ways first by direct injection... 

Ammonia G A Coal distillation (coke ovens) Nitric acid production Urea and ammonium nitrate works... 

The economic operation of processes which involve the compression and expansion of large quantities of gases, such as ammonia synthesis, nitric acid production and air... 

In addition to the gaseous emissions from the combustion of fuel, gaseous emissions are also produced by chemical production, for example, SO, from sulfuric acid production, NO from nitric acid production, HC1 from chlorination reactions, and so on. 

Fixed Bed Reactors. In its most basic form, a fixed bed reactor consists of a cylindrical tube filled with catalyst pellets. Reactants flow through the catalyst bed and are converted into products. Fixed bed reactors are often referred to as packed bed reactors. They may be regarded as the workhorse of the chemical industry with respect to the number of reactors employed and the economic value of the materials produced. Ammonia synthesis, sulfuric acid production (by oxidation of S02 to S03), and nitric acid production (by ammonia oxidation) are only a few of the extremely high tonnage processes that make extensive use of various forms of packed bed reactors. 

Let the rest of the world depend on Chile Germany needed her no more. During these first eight months of 1939, by the Haber-Bosch process alone, Farben had doubled the whole Chilean output of nitrates. Nitric-acid production had jumped tenfold since 1933, methanol by six hundred or more. On that first day, diglycol was produced at a rate which would make 50,000 tons of gunpowder every month. 

Ammonia oxidation process, of nitric acid production, 17 170-171 Ammonia oxidation reactions, 10 98 Ammonia plant functions of, 17 293 as reliability example, 26 994-997... 

Dual nickel, 9 820—821 Dual-pressure processes, in nitric acid production, 17 175, 177, 179 Dual-solvent fractional extraction, 10 760 Dual Ziegler catalysts, for LLDPE production, 20 191 Dubinin-Radushkevich adsorption isotherm, 1 626, 627 Dubnium (Db), l 492t Ductile (nodular) iron, 14 522 Ductile brittle transition temperature (DBTT), 13 487 Ductile cast iron, 22 518—519 Ductile fracture, as failure mechanism, 26 983 Ductile iron... 

Expanded-film membranes, 15 802-803 Expanded graphite, 12 794-795 Expanders, in nitric acid production, 17 178... 

Monopressure processes, in nitric acid production, 17 175, 176 Monopril, molecular formula and structure, 5 150t... 

C. G. Vayenas and R. D. Farr, Science 208, 593 (1980), describe a solid electrolyte fuel cell in which ammonia is the fuel and is catalyt-ically converted at 1000 K with oxygen (or air) to nitric oxide. The idea is that the energy released in this step in industrial nitric acid production (Section 9.4) could be recovered directly as electricity. 

In 1957 Hercules Inc. started the first unit that produced concentrated nitric acid for commercial sales using magnesium nitrate as the extractive agent. In this process (see Figure 2) the weak nitric acid product from an AOP is fed to the appropriate tray of a distillation column. A concentrated solution of magnesium nitrate and water is fed to the proper tray in sufficient quantity to enrich the vapors to a concentration greater than 68 wt % nitric acid. The overhead product from the column is concentrated (98-99.5 wt %) nitric acid. A portion of the concentrated nitric acid is returned as reflux to aid in rectification. The... 

If nitrous and nitric oxides are present in the nitric acid, products of oxidation may contaminate the main product. Such dinitroglycerine should be washed with special care. The product is dried by passing a stream of warm air through it. 

Notably, all commercial nitric acid production methods used today are centred around the oxidation of ammonia. It is therefore appropriate to investigate the chemistry of this process, in the knowledge that it is directly applicable to any of the production... 

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