The production of nitric acid

Nitric acid is manufactured from anhydrous ammonia, air and water by the following series of reactions (all exothermic). 

In order to obtain high yields the following side reactions must be avoided. 

To avoid this the hold-up volume in the catalyst bed must be kept as low as possible. 

The only way to avoid this reaction is to avoid contact between ammonia and nitric oxide. It is for this reason mainly that the flow rate is controlled to make sure as little as possible of the NH3 is unreacted on the catalyst bed. Care must also be taken to ensure as little NO as possible is in the entering gas. 

Unfortunately, in order to achieve high conversion rates it can be seen that (a)-(c) lead to low thermal efficiency. The process is most efficient at atmospheric pressure which in many ways is inconvenient as stages 2 and 3 are best carried out at high pressures. Normally stage 1 is worked at 1-4 atmospheres and the remainder at about 10 atmospheres. 

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A major step in the production of nitric acid [7697-37-2] (qv) is the catalytic oxidation of ammonia to nitric acid and water. Very short contact times on a platinum—rhodium catalyst at temperatures above 650°C are required. 

The catalyst temperature is about 1100°C. Precious metal catalysts (90% Pt/10% Rh in gauze form) are normally used in the commercial processes. The converters are similar to the ammonia oxidation converters used in the production of nitric acid (qv) although the latter operate at somewhat lower temperatures. The feed gases to the converter are thoroughly premixed. The optimum operating mixture of feed gas is above the upper flammabiUty limit and caution must be exercised to keep the mixture from entering the explosive range. 

The most important use of ammonia is in the production of nitric acid (HNO3). Ammonia burns in oxygen, releasing hydrogen to form water and free nitrogen. With the catalysts platinum and rhodium, ammonia is oxidized and reacted with water to form nitric acid. Nitric acid treated... 

Nitric oxide is the simplest thermally stable odd-electron molecule known and, accordingly, its electronic structure and reaction chemistry have been very extensively studied. The compound is an intermediate in the production of nitric acid and is prepared industrially by the catalytic oxidation of ammonia (p. 466). On the laboratory scale it can be synthesized from aqueous solution by the mild reduction of acidified nitrites with iodide or ferrocyanide or by the disproportionation of nitrous acid in the presence of dilute sulfuric acid ... 

Absorption of Nitrogen Oxides in Water to Form Nitric Acid Solution. The production of nitric acid from nitrous gases such as are obtained in... 

H.20 The first stage in the production of nitric acid by the Ostwald process is the reaction of ammonia gas with oxygen gas, producing nitric oxide gas, NO, and liquid water. The nitric oxide further reacts with oxygen to produce nitrogen dioxide gas, which, when dissolved in water, produces nitric acid and nitric oxide. Write the three balanced equations that lead to the production of nitric acid. 

C04-0069. Most of the ammonia produced by the Haber process is used as fertilizer. A second important use of NH3 is in the production of nitric acid, a top-15 industrial chemical. Nitric acid is produced by... 

By far the most important use of the platinum metals is for catalysis. The largest single use is in automobile catalytic converters. Platinum is the principal catalyst, but catalytic converters also contain rhodium and palladium. These elements also catalyze a wide variety of reactions in the chemical and petroleum industry. For example, platinum metal is the catalyst for ammonia oxidation in the production of nitric acid, as described in Pt gauze, 1200 K... 

Ammonia is produced in huge quantities, and it is by far the most common and important compound of nitrogen and hydrogen. Approximately 30 billion pounds of NH3 are used annually with a large portion being used as fertilizer or in the production of nitric acid. Ammonia is produced by the Haber... 

Ammonia is also the starting material for the production of nitric acid, and the first step is oxidation of ammonia by the Ostwald process. 

Used industrially for the production of nitric acid and as a nitrating agent, oxidizing agent polymerization inhibitor for acrylates and as an oxidizer for rocket fuels. 

The oxidation of ammonia (one of the reactions in the production of nitric acid) ... 

One of the steps in the Ostwald process for the production of nitric acid involves the oxidation of ammonia. 

In the production of nitric acid the reaction is accomplished with mixtures of ammonia and air or sometimes with mixtures of ammonia, air, and oxygen, containing about 10 vol % NH3 at pressures of 1-10 atm (below... 

Determine the values of AH° and AS° for each stage of the Ostwald process for the production of nitric acid. Predict the conditions of pressure and temperature that favor the formation of the products in each case. 

Ostwald process The production of nitric acid by the catalytic oxidation of ammonia, overall order The sum of the powers to which individual concentrations are raised in the rate law of a reaction. Example If the rate = [S02][S03]" l/2, then the overall order is f. 

Researchers returned to the oxidation of ammonia in air, (recorded as early as 1798) in an effort to improve production economics. In 1901 Wilhelm Ostwald had first achieved the catalytic oxidation of ammonia over a platinum catalyst. The gaseous nitrogen oxides produced could be easily cooled and dissolved in water to produce a solution of nitric acid. This achievement began the search for an economic process route. By 1908 the first commercial facility for production of nitric acid, using this new catalytic oxidation process, was commissioned near Bochum in Germany. The Haber-Bosch ammonia synthesis process came into operation in 1913, leading to the continued development and assured future of the ammonia oxidation process for the production of nitric acid. 

Part II of the Design Project (Case Study) for the production of nitric acid concerns the design of two main plant units (the NOx absorption column and the steam superheatei), a pump to deliver red product acid from the absorption column to the product bleaching column, and finally a product storage tank. 

This section discusses the design of a suitable absorption column for the production of nitric acid by the single-pressure process. A comprehensive design study determined the column mechanical details and physical characteristics, together with its anticipated performance. This chapter contains the operating criteria and product specifications, the solution method, and finally the results of the design calculations. Details of the design calculations and all associated data are included in Appendix G. 

Al. V.l. Glushchenko and E.D. Kirichuk, Mathematical Model of Absorption Columns for the Production of Nitric Acid , International Chemical Engineering, 22 (1 ), pp. 181-1 86 (1982). 

Gauzes are the state of the art for many millisecond-reactions performed in industry. The best-known examples are the oxidation of ammonia to NO for the production of nitric acid and the Andrussov process, in which HCN is produced from methane and ammonia (32) ... 

The use of nitrates as raw materials for the production of nitric acid has already been discussed. On a quantity basis, however, this application accounts for only a relatively small proportion of the annual consumption of these salts by the chemical industries. 

In the days when anhydrous nitric acid was not easily available, nitric acid salts (NaN03, KN03) mixed with sulphuric acid were widely used for nitration. Such mixtures acted similarly to the mixture of nitric and sulphuric acids. Later, as synthetic nitric acid became one of the most readily available chemical products, and the production of nitric acid salts from nitric acid had started, nitrating mixtures with sodium or potassium nitrates were abandoned. This is the principal explanation for the scarcity of investigations on the structure and action of such mixtures. It is believed that in such mixtures the nitronium ions are present, according to the equation ... 

Draw and name the products of nitric acid oxidation of (a) D-mannose (b) D-galactose... 

Ammonia is found in the environment as the result of natural and industrial processes. It is released into the environment by the breakdown of organic wastes, and it is a constituent of the soil, the atmosphere, and bodies of water. Ammonia is also a key intermediate in the nitrogen cycle and is a product of amino acid metabolism (WHO 1986). Anhydrous ammonia is used in the production of nitric acid, explosives, synthetic fibers, and fertilizers (Budavari 1989). It is used as a refrigerant as a corrosion inhibitor in the purification of water supplies in steel production as a catalyst for polymers as a preservative for latex and in the production of nitrocellulose, urea formaldehyde, sulfite cooking liquors, and nitroparaffins (ACGIH 1991 Lewis 1993). Ammonium hydroxide (10-35% ammonia) is a major constituent of many cleaning solutions. Ammonia... 

A qualitative flow diagram indicates the flow of materials, unit operations involved, equipment necessary, and special information on operating temperatures and pressures. A quantitative flow diagram shows the quantities of materials required for the process operation. An example of a qualitative flow diagram for the production of nitric acid is shown in Fig. 2-1. Figure 2-2 presents a quantitative flow diagram for the same process. 

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