Industrial manufacture Haber Process

Nitrogen is a diatomic molecule, which is effectively triple-bonded and has a high dissociation energy (940 kj mol" ). It is therefore inert and it only reacts readily with lithium and other highly electropositive elements. The direct combination of nitrogen and hydrogen occurs at elevated temperatures and pressures (400-600°C, 100 atmospheres) and is the basis of the industrially important Haber process for the manufacture of ammonia. 

Bosch also helped develop Haber s process into an industrial process. In 1913, Haber and Bosch opened an ammonia manufacturing plant in Germany. A year later, World War I started. Saltpeter had another use besides making fertilizer. It was also necessary to make nitric acid that was used to make explosives. When the war started, the British Navy quickly cut off Germany s supply of Chilean saltpeter. If not for the Haber process, some historians estimate that Germany would have run out of nitrates to make explosives by 1916. The war lasted another two years, however, because Germany did not need to rely on outside sources of nitrates for fertilizers or explosives. 

The conditions used industrially for the Haber process are those that sustain the economic viability of its manufacture. Out of necessity, a high yield in a long time must be balanced against a low yield in a shorter time, whilst minimising energy costs. The conditions employed indicate a compromise between these opposing outcomes, as the graphs illustrate. 

In this chapter, you learned about the Haber process for manufacturing ammonia. You used this process to help you understand various concepts related to equilibrium. As you can see in Figure 7.11, ammonia is a valuable industrial chemical. Its annual global production is well over 100 million tonnes. The vast majority of ammonia, roughly 80%, is used to make fertilizers. You will now examine how the equilibrium concepts you have been studying work together to provide society with a reliable, cost-effective supply of ammonia. 

The importance of catalysts in chemical reactions cannot be overestimated. In the destruction of ozone previously mentioned, chlorine serves as a catalyst. Because of its detrimental effect to the environment, CFCs and other chlorine compounds have been banned internationally. Nearly every industrial chemical process is associated with numerous catalysts. These catalysts make the reactions commercially feasible, and chemists are continually searching for new catalysts. Some examples of important catalysts include iron, potassium oxide, and aluminum oxide in the Haber process to manufacture ammonia platinum and rhodium in the Ostwald synthesis of nitric... 

Approximately 95% of the H2 produced in industry is synthesized and consumed in industrial plants that manufacture other chemicals. The largest single consumer of hydrogen is the Haber process for synthesizing ammonia (Sections 13.6-13.10) ... 

O chemical plant the reaction vessels and equipment for manufacturing chemicals O feedstock starting materials for chemical industrial processes O brine a concentrated solution of sodium chloride O Haber process the industrial process for the manufacture of ammonia O Contact process the industrial process for the manufacture of sulfuric aod... 

The demand for nitrogen in a chemically fixed form (as opposed to elemental nitrogen gas) drives a huge international industry that encompasses the production of seven key chemical nitrogen products ammonia, urea, nitric acid, ammonium nitrate, nitrogen solutions, ammonium sulfate and ammonium phosphates. Such nitrogen products had a total worldwide annual commercial value of about US 50 billion in 1996. The cornerstone of this industry is ammonia. Virtually all ammonia is produced in anhydrous form via the Haber process (as described in Chapter 2). Anhydrous ammonia is the basic raw material in a host of applications and in the manufacture of fertilizers, livestock feeds, commercial and military explosives, polymer intermediates, and miscellaneous chemicals35. 

The amount of ammonia formed in a single pass of the synthesis gas over the catalyst is much too small to be of interest for an economic production. Haber therefore recycled the unconverted synthesis gas. After separating the ammonia by condensation under synthesis pressure and supplementing with fresh synthesis gas to make up for the portion converted to ammonia, the gas was recirculated by means of a circulation compressor to the catalyst-containing reactor. This process, described in the patent DRP 235 421 (1908), became the basis for the industrial manufacture of ammonia and since then the same principle has found widespread application in numerous high-pressure processes. Haber also anticipated the preheating of the synthesis gas to reaction temperature (at that time 600 °C) by heat exchange with the hot exhaust gas from the reactor, the temperature of which would be raised by the exothermic ammonia formation reaction sufficiently (about 18 °C temperature rise for a 1 % increase of the ammonia concentration in converted synthesis gas). 

Ammonia is a very important industrial chemical that is used as a fertilizer and in the manufacture of many other chemicals. The reaction of nitrogen with hydrogen is a thermodynamically spontaneous reaction (product-favored), but without a catalyst it is very slow, even at high temperatures. The Haber process for its preparation involves the use of iron as a catalyst at 450°C to 500°C and high pressures. 

The industrial manufacture of NH, (see Figure 26.13) involves the Haber process (reaction 14.19), and the... 

Many industrial reactions, such as the Haber process for manufacturing... 

Haber process /hay-ber/ An important industrial process for the manufacture of ammonia, which is used for fertilizers and for making nitric acid. The reaction is the equilibrium ... 

Haber process This is used in the industrial manufacture of ammonia. 

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