Industrial processes Haber-Bosch process

Hnman-indnced N-fixation— For about 60 years mankind has used industrial processes (Haber-Bosch) to form ammonia through the combination of hydrogen and atmospheric nitrogen under high pressure and temperature. Globally, industrial N-fixation through fertilizer... 

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 catalytic synthesis of ammonia from its elements via the Haber-Bosch process is of major industrial importance. The high pressure synthesis is catalyzed by Fe promoted with K20, CaO and A1203. 

The enzyme systems responsible for fixing atmospheric N2 to form ammonia are known as the nitrogenases. These enzymes function at field temperatures and 0.8 atm N2 pressure, whereas the industrial Haber-Bosch process requires high temperatures (300-400°C) and high pressures (200-300 atm) in a capital-intensive process that relies on burning fossil fuel. Small wonder, then, that the chemistry of the nitrogenases has attracted considerable attention for many years. 

Industrially, ammonia has been produced from dinitrogen and dihydrogen by the Haber-Bosch process, which operates at very high temperatures and pressures, and utilizes a promoted iron catalyst. Millions of tons of ammonia are generated annually for incorporation into agricultural fertilizers and other important commercial products. The overall reaction is exergonic, as indicated in equation 6.1 ... 

Production of ammonia (NH ) Anhydrous (dry) ammonia is the fifth most produced industrial compound. The Haber-Bosch process uses steam on hot coke, which is mostly used in South Africa. In the United States, it is mostly produced from partial combustion of natural gas (methane) or by combining several gases using steam. Other methods use coke-oven gas, refinery gas (mostly methane), or even solar energy. Ammonia is toxic if inhaled and has a high pH value when mixed with water (hydration) to form ammonium hydroxide (NH OH), which has many uses, including as a household cleaner. Ammonia forms many compounds, including ammonium nitrate in fertilizer, rocket fuel, and explosives. Ammonia is also explosive when mixed with mercury or silver or when mixed as part of nitrocellulose. 

Carl Bosch developed the industrial stages for the Haber Process. The perfection of the Haber-Bosch process was used by Germany during World War I. Haber also worked on the thermodynamics of gaseous reactions, the electrochemistry and the explosion of gases. 

Haber process also known as the Haber-Bosch process, this industrial process uses nitrogen (N2) and hydrogen (H2) to produce NH3. 

In nature, ammonia is produced by the action of nitrogen-fixing bacteria on atmospheric N2 under very mild conditions (room temperature and 0.8 atm N2 pressure). These bacteria contain nitrogenases, iron- and molybdenum-containing enzymes that catalyze the formation of NH3. Industrially, NH3 is synthesized from its elements by the Haber-Bosch process, which typically uses finely divided iron as catalyst ... 

Synthesis of ammonia in the Haber-Bosch process is one of the best studied catalytic processes. The process was developed by Fritz Haber and Carl Bosch and patented in 1910 (Haber, 1910) Haber was awarded the Nobel Prize in chemistry in 1918 for this work. Today, almost all ammonia production is based on the Haber-Bosch process, and it is one of the largest chemical processes in the world with a yearly production of approximately 120 million tonnes (from the International Fertilizer Industry Association, World Ammonia Statistics for 2005). The main use of ammonia is as fertilizer for agriculture, which constitutes 80% of the world production. 

Nitric acid is an important industrial chemical and is manufactured on a large scale in the Haber-Bosch process closely tied to NH3 production the first step is the oxidation of NH3 to NO (equation 14.21). After cooling, NO is mixed with air and absorbed in a countercurrent of water. The reactions involved are summarized in scheme 14.109 this produces HNO3 in a concentration of a 60% by weight and it can be concentrated to 68 %> by distillation. 

In the following sections some aspects of (potential) applications of sc-fluids in the fine chemical industry with respect to product separation/purification and catalytic reactions are discussed. Earlier industrial applications of supercritical fluid reactions, for example the Haber-Bosch process for the synthesis of ammonia, synthesis of methanol from hydrogen and carbon monoxide, or the polymerization of ethene will not be discussed. An extensive overview on the use of sc-fluids in the synthesis of bulk chemicals is given in the book edited by fessop and Leitner [12],... 

Carbon dioxide is obtained commercially as the byproduct of a number of industrial reactions. For example, when calcium carbonate is heated to produce lime (CaO), carbon dioxide is released and captured as a by-product. The steam reforming (refining) of petroleum results in the production of a mixture of gases known as synthesis gas, consisting of carbon dioxide, carbon monoxide, hydrogen, and nitrogen. Carbon dioxide can be separated from the other components of synthesis gas for commercial uses. Carbon dioxide also produces as a by-product of the manufacture of ammonia (NH3) by the Haber-Bosch process. 

However Carl Bosch developed it for industrial use, leading to the alternative name Haber-Bosch Process. 

Haber-Bosch process the large-scale industrial process in which ammonia is synthesized from hydrogen and nitrogen gas in the presence of a catalyst. 

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