Nitric acid production processes

Initial production of the dimethyl terephthalate started with the oxidation of -xylene to terephthaUc acid using nitric acid both companies reportedly used similar technology (43—45). Versions of the nitric acid oxidation process, which has been abandoned commercially, involved the use of air in the initial oxidation step to reduce the consumption of nitric acid (44,46,47). The terephthaUc acid was then esterified with methanol to produce dimethyl terephthalate, which could be purified by distillation to the necessary degree (48). 

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... 

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... 

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... 

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

It is not only the esters of organic acids which combine, in the manner of the ethyl acetoacetate synthesis , with the enolates of ketones and of esters an analogous behaviour is shown by the esters of nitrous and nitric, acids. The process which leads to the formation of isonitroso-and atinitro-compounds yields products fundamentally similar to those already described just as with ethyl acetate the group CO.CHs enters, so here, the NO- and N02-groups are involved, and enolise " exactly as does >O=0 ... 

Iso-Trioil. A product resulting from the purification of crude TNT by recrystallization from nitric acid. This process has been used in Europe on a production scale however, the Sellite purification process was selected for use in the USA. Isotrioil has been found to be a satisfactory substitute for TNT in Dynamite consisting of ... 

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... 

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... 

All commercially produced nitric acid is now prepared by the oxidation of ammonia. The requirement for a nitric acid product of 60%(wt.) immediately restricts the choice of a recommended production process. Only two processes are possible, both highly efficient, each offering distinct advantages under different market conditions. 

Section 3.2.2 compares these leading process technologies in order to select the most applicable method of weak nitric acid production. The most appropriate process is discussed fully in Section 4.2. Summaries of both processes are included in Appendix C. 

Some of the principal variations between these processes are different operating temperatures, different operating pressures and different concentrations of the nitric acid product. Other differences include catalysts and spent catalyst recovery systems. In the 1990 s, new air emission control requirements necessitated the modification of some plants and prompted the re-evaluation of processes for new plants. This resulted in a trend toward plants... 

Catalysts and supports. The oxidation of ammonia by the oxygen of air is known to be the main industrial process for nitric acid production. The process includes three stages the oxidation of NH3 into NO by the oxygen of air in the presence of catalysts 4 NH3 + 5 O2 = 4 NO + 6 H2O, the... 

A few classicaV studies on the reactivity of HCs to reduce NOx with catalysts indicated that the use of such reductants for controlling mobile NOx emissions was quite attractive to the automotive industry, thereby the advent of a new type of HC-SCR technology in the mid-1980s. An example may be the treatment process of the tail gas from nitric acid production plant via ammonia oxida-tion. The process includes the usual injection of excessive amounts of HCs over supported noble metals such as Pt, Pd and Rh to eliminate the yellowish stack plume due to 0.1 - 0.5% NOx, mainly NO2, from the nitric acid plant. 

Present-day nitric acid production is almost entirely via the oxidation of ammonia and absorption of the oxidation products in water. The chemistry of this process was proven experimentally by Kuhlmann in 1839, but had to wait for the development of an economical route to ammonia before it could become commercially significant [38]. Ostwald, working in Germany in about 1900, reexamined and extended Kuhlmann s data and established the proper conditions required for the ammonia oxidation step. Very shortly after this plants operating on these principles were constructed both in Germany and the U.S. Since 1980, 3-5 million metric tonnes of nitric acid (100% basis) have been produced annually in Germany, and 7-9 million tonnes in the U.S. (Table 11.7). 

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