Ammonia manufacture compression

In the C. F. Braun process for ammonia manufacture, excess air is added in the second reformer. The excess nitrogen thus introduced must be removed prior to the synthesis step to avoid excessive loss of hydrogen and excessive compression costs. At the same time that the excess nitrogen is condensed and removed, the remaining traces of carbon monoxide, the methane, and most of the argon are removed, leaving a gas comparable to that produced by the nitrogen wash operation. 

About 20 percent of the energy used in ammonia manufacture goes into compression (synthesis gas, air, and refrigeration). A study of new alternatives suggests that gas turbines and more efficient steam systems (higher temperatures and reheat) should be considered. 

Ammonium nitrate is manufactured by reacting ammonia with nitric acid. Consider the process shown by Fig. 9.19. First, namral gas is reformed and converted into hydrogen, nitrogen and carbon dioxide. Hydrogen and nitrogen are separated an fed to the ammonia synthesis plant. A fraction of the produced ammonia is employed in nitric acid formation. Ammonia is first oxidized with compressed air then absorbed in water to form nitric acid. Finally nitric acid is reacted with anunonia to oduce ammonium nitrate. 

Devices for compressing gases are used extensively in the chemical industry (see "High Pressure Techniques"), eg, in the manufacture of nitric acid by the ammonia oxidation process Compressors for transferring gases and vapors may be divided into vacuum pumps or exhausters (when the gas is below atmospheric pressure) and into fans, blowers, boosters and ax . I compressors (when the gases are above atmospheric pressure)... 

Hydrogen escaping from a diaphragm electrolyzer is purified in this way, and can be used for chemical or other purposes, i. e. hydrogenation, the manufacture of ammonia or to produce compressed hydrogen etc. 

For developments in ammonia synthesis during the late 1920s, and in particular of compressors see High pressures in the manufacture of synthetic ammonia. Recent designs in compressing plant, Chemistry and Industry, 48 (1929), 591-598. 

Ammonia is used commercially in the manufacture of fertilizers, mainly ammonium nitrate, urea, and ammonium sulfate. It is also used to make explosives, resins, and dyes. As a liquefied gas it is used in the refrigeration industry. Liquid ammonia is an excellent solvent for certain substances, which ionize in the solutions to give ionic reactions similar to those occurring in aqueous solutions. Ammonia is marketed as the liquid, compressed in cylinders ( anhydrous ammonia ), or as aqueous solutions of various strengths. See also ammonium hydroxide. 

Ostwald process The manufacture of nitric acid by the catalytic oxidation of ammonia. In the first step of the process, compressed air and ammonia react (at 1,472°F [800 C] in the presence of a platinum gauze catalyst) to give nitrogen monoxide and water. 

Natural gas, which is mostly methane, is widely used as a fuel. In the chemical industry, methane is used heavily as a raw material for making important products that include acetylene, ammonia, ethanol, and methanol its chlorination also yields carbon tetrachloride, chloroform, methyl chloride, and methylene chloride. It is used to produce carbon black for use in the manufacture of rubber products and printing inks. The burning of high-purity methane is used to make carbon black of special quality for electronic devices. Natural gas has seen limited use as a motor fuel handled as a compressed gas in high pressure cylinders or liquid dewars. 

Using ammonia as a hydrogen carrier involves the manufacture of the compound from natural gas and atmospheric nitrogen, the compression of the product gas into liquid form, and then, at the point of use, the dissociation of the ammonia back into nitrogen... 

Ammonia is also produced in ammonia plants as a raw material for the manufacture of urea and other nitrogen-based fertilizers. Ammonia in synthesis gas at temperatures between 450 and 500 °C causes nitridation of steel components. When synthesis gas is compressed to up to 34.5 MPa (5000 psig) prior to conversion, corrosive ammonium carbonate is formed, requiring various stainless steels for critical components. Condensed ammonia is also corrosive and can cause stress corrosion cracking (SCC) of stressed carbon steel and low-alloy steel components. 

Macroporous open-cell nickel foam substrate was manufactured by the nickel electroplating of the polyurethane foam samples (cell density 60 ppi) followed by sintering in the dissociated ammonia atmosphere at 1100°C for 1 h. The foam samples were then deformed by a imiaxial compression to 1 mm thickness modifying the cell morphology and decreasing porosity from 95.5 % to 60-80 %. Deformed foams were subjected to the pack aluminizing and then annealed at 1000 C for 1 h under air to form a thin a-aliunina layer over the foam cell walls/ribs for a better adhesion of composite layers. 

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