Synthetic ammonia Haber-Bosch process

The synthetic ammonia industry of the latter part of the twentieth century employs only the Haber-Bosch process (12—15), developed in Germany just before World War 1. Development of this process was aided by the concurrent development of a simple catalyzed process for the oxidation of ammonia to nitrate, needed at that time for the explosives industry. N2 and H2 are combined direcdy and equiUbrium is reached under appropriate operating conditions. The resultant gas stream contains ca 20% ammonia. 

The modem process for manufacturing nitric acid depends on the catalytic oxidation of NH3 over heated Pt to give NO in preference to other thermodynamically more favour products (p. 423). The reaction was first systematically studied in 1901 by W. Ostwald (Nobel Prize 1909) and by 1908 a commercial plant near Bochum. Germany, was producing 3 tonnes/day. However, significant expansion in production depended on the economical availability of synthetic ammonia by the Haber-Bosch process (p. 421). The reactions occurring, and the enthalpy changes per mole of N atoms at 25 C are ... 

The most important method of synthetic N fixation is by the Haber-Bosch process. Ammonia is synthesized from a 3 1 volume of H2 and N2 at elevated temperature and pressure in the presence of a catalyst ... 

The high pressure Haber-Bosch process for synthetic ammonia, and its widespread impact, overshadows developments described in many of the following chapters. High pressure industrial chemistry was nothing less than the paradigm shift that thrust the chemical industry into the 20th century. It is thus appropriate to commence our story with an overview of the Haber-Bosch process and its imitators. 

LICENSING STRATEGY SYNTHETIC AMMONIA AND SYNTHETIC OIL Licensing of the Haber-Bosch process... 

Ammonia was first produced in the United States on a commercial basis around 1890 as a by-product of the destructive distillation of coal in the manufacture of coke and coal gas. The first commercially successful synthetic ammonia plant in the United States was put into operation in 1921. It utilized the Haber-Bosch process, in which a preheated mixture of nitrogen and hydrogen was subjected to pressure in the presence of a catalyst. 

The fixation of atmospheric nitrogen through both the electric arc and calcium cyanamide routes were thus put into commercial practice. Both processes suffered from large requirements of electrical energy for the synthesis and were replaced before long by the direct synthesis of ammonia from its elements, which has become known as the Haber-Bosch process. Since Ostwald had developed a method for the oxidation of ammonia to produce nitric acid at the beginning of the century (1902), synthetic ammonia provided the basis for an industrial route to nitric acid. 

About 85% of all nitrogen in food proteins available for human consumption (21 out of 24.5 Mt N) thus came—directly in plant foods or indirectly in animal products—from the world s cropland. And because synthetic nitrogen fertilizers provided about half (44-51%) of the nutrient in harvested crops, roughly 40% (37-43%) of the world s dietary protein supply in the mid-1990s originated in the Haber-Bosch synthesis of ammonia (fig. 8.1). But this global mean both overestimates and underestimates the degree of our dependence on the Haber-Bosch process because the... 

Karl Bosch (1874-1940) and Alwin Mittasch (1869-1953) of Badische Anilin- und Soda-Fabrik eliminated the nitrate shortage that occurred after the British sea blockade effectively cut off the nitrate supply from Chile. By May of 1915, they had successfully developed at their Oppau Plant an industrial-scale process for oxidizing ammonia. Their process converted the large quantities of synthetic ammonia produced by the Haber process to nitric acid and other nitrates that were essential for fertilizers and explosives. (10)... 

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