Nitrate fertilizer plants

Ammonia from coal gasification has been used for fertilizer production at Sasol since the beginning of operations in 1955. In 1964 a dedicated coal-based ammonia synthesis plant was brought on stream. This plant has now been deactivated, and is being replaced with a new faciUty with three times the production capacity. Nitric acid is produced by oxidation and is converted with additional ammonia into ammonium nitrate fertilizers. The products are marketed either as a Hquid or in a soHd form known as Limestone Ammonium Nitrate. Also, two types of explosives are produced from ammonium nitrate. The first is a mixture of fuel oil and porous ammonium nitrate granules. The second type is produced by emulsifying small droplets of ammonium nitrate solution in oil. 

Biocorrosion in well-oxygenated cooling systems can also involve other types of bacteria, such as nitrifying bacteria, which are commonly found where ammonia is present (say from refinery or fertilizer plant leaks). They are principally aerobic and oxidize ammonia to nitrate, causing serious local falls in pH that result in nitric acid corrosion. Examples are Nitrosomonas sp. and Nitrobacter sp. 

Weak extractants such as calcium chloride or nitrate for plant uptake studies, soil fertility studies, and risk assessment... 

In contrast to SCC of carbon and low-alloy steels in chloride, sulfide, and sulfuric acid environments by hydrogen-embrittlement mechanisms, cracking in several environments is attributed to passive-film cracking and/or active-corrosion-path anodic-dissolution penetration mechanisms (Ref 124). These environments include nitrates, hydroxides, ammonia, carbon-dioxide/carbonate solutions, and aqueous car-bon-monoxide/carbon-dioxide. Nitrate-bearing solutions are encountered in coal distillation and fertilizer plants hydroxide solutions in the production of NaOH and in crevices of steam boilers and ammonia cracking has occurred in tanks and distribution systems for agricultural ammonia applications. 

The primary use of ammonium nitrate is the manufacture of fertilizers. In 2005, about 2 million metric tons (2.2 million short tons) of ammonium nitrate fertilizer was used in the United States. The compound is added to soil to provide the nitrogen that plants need to grow. It may he used by itself or in combination with another nitrogen-rich compound, urea, in a mixture known as UAN. 

In an earlier disaster, a warehouse full of ammonium nitrate exploded in a chemical plant in Germany, killing thousands. A mixture of ammonium nitrate fertilizer and fuel oil was a tool in the Oklahoma City bombing in 1995. Such combinations are common industrial explosives. As mentioned earlier, the presence of flammable or combustible material can accelerate the fire and sustain it because of nitrous oxide and/or oxygen released during the exothermic decomposition of ammonium nitrate. 

A freighter, the Grand Camp, carrying 1,400 tons of ammonium nitrate fertilizer exploded after fire broke out on board. The initial explosion set off a series of secondary explosions that destroyed much of Texas City. The blast rattled windows 150 miles away and the leaping flames also destroyed a nearby Monsanto plant producing a styrene. The next day another freighter, the High Flyer, also loaded with nitrates, exploded in the same harbor. Some 576 people were killed and 2,000 others seriously injured. 

The first patent on ammonia oxidation wras issued to Khulman in 1839 in this case platinum was used as a catalyst to oxidize ammonia with air. The ammonia-oxidation method using a platinum catalyst qn a commercial scale, developed by Oswald and Brauer and first operated in Germany about 1908, is at present the principal industrial method of nitric acid producticxi. The main use for nitric acid is in fertiDzer production, mainly for ammonium nitrate as such or in compound fertilizers, nitrogen solutions, or mixed salts. About 75% of total nitric acid production is consumed for nitrate fertilizers, mainly as 509 5% concentration acid. Smaller fertilizer uses are for calcium and potassium nitrates. A primary use is in addulation of phosphate rock for production of nitrophosphates. Plant capacities for weak nitric acid i Bed for fertilizer production are in the range of 35 to 1,380 tpd althoi h capacities of 2,000 tpd have been designed. 

Pomfret, J. G. 1992. Zero Water Discharge From Urea and Ammonium Nitrate Plants," Unpublished,. European fertilizer plant retrofitting conference, Budapest, Hungary. 

Those vegetables which are most apt to contain high levels of nitrates include beets, spinach, radishes, and lettuce. Despite the shift from manure to chemical fertilizers over the years, the overall average concentration of nitrate in plants has remained unchanged. Other natural sources of nitrate are negligible. 

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