Ammonia production capacity

Since no economical nitrogen fixation process that starts with nitrogen oxides has been discovered, ammonia has developed into the most important building block for synthetic nitrogen products worldwide. Prior to World War II, ammonia production capacity remained relatively stable. But during the war the need for explosives caused an increase in the production of ammonia for nitric acid manufacture. Then, after the war, the ammonia plants were used to manufacture fertilizers. As a result, there was a rapid increase in fertilizer consumption. The advantages of fertilizers were emphasized, and production capacity increased by leaps and bounds. 

In 1998 most of the ammonia production capacity was located in the regions shown in Table 22.3.36 57... 

Commercial plants More than 60 plants use the Topsoe process concept. Since 1990, 50% of the new ammonia production capacity has been based on the Topsoe technology. Capacities of the plants con-... 

Table 21. Feedstock distribution of world ammonia production capacity... 

Ammonia is one of the most important bulk chemicals in the world world wide production of ammonia having grown from 93 million tons in 1977 to 137 million tons in 1985 (Austin, 1984). Ammonia is mostly used in the production of a wide variety of fertilizers hence, coupled with the acute food supply problem in the third world, it represents a strategic commodity for these countries. Egypt has an ammonia production capacity of 1.2 million tons/year and is expected to double in the next few years. Saudi Arabia is producing about 1.5 million tons/year. Ammonia production is also quite large in some developed nations, e.g. Canada produces about 4 million tons/year. 

Figure 3.13. Ammonia Production Capacity in the United States, Number of Producing Companies, 1975>95.

New Asian, Middle Eastern, and Latin American ammonia plants built since the 1960s have been based overwhelmingly on natural gas. Consequently, reforming of natural gas has come to dominate the global synthesis of ammonia gas-based plants, which also use the methane as the principal source of their process energy, now account for about 80% of the world s ammonia production capacity. 

Some of the physical properties of fatty acid nitriles are Hsted in Table 14 (see also Carboxylic acids). Eatty acid nitriles are produced as intermediates for a large variety of amines and amides. Estimated U.S. production capacity (1980) was >140, 000 t/yr. Eatty acid nitriles are produced from the corresponding acids by a catalytic reaction with ammonia in the Hquid phase. They have Httie use other than as intermediates but could have some utility as surfactants (qv), mst inhibitors, and plastici2ers (qv). 

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. 

In 1984, the Ube Ammonia Industry Co. began operating the largest Texaco coal gasification complex to date. This faciUty is located in Ube City, Japan, and has a rated gasification capacity of 1500 t/day of coal, and production capacity of 1000 t/day of ammonia. The plant has successfully gasified coals from Canada, AustraUa, South Africa, and China. At the present time the plant uses a mixture of petroleum coke and coal (43). 

Capacity, Production, and Consumption. Ammonia production has worldwide significance about 85% of the ammonia produced is used for nitrogen fertilizers. As the primary source of fertilizer nitrogen, it is key to solving world food production requkements. The remaining 15% goes into various industrial products such as fibers, animal feeds, explosives, etc. 

Several modifications in plant design and process conditions for ammonia oxidation processes have taken place in recent years. These variations are more or less based on operating pressures and temperatures, reduction of NOx emission and other environmental regulations, and the desired plant production capacity. 

From 1940 to 1950 the number of ammonia plants doubled then from 1950 to 1960 the number more than doubled again. Since 1963, there has been a revolution in ammonia-manufacturing technology. The advent of large singletrain plants has resulted in a large increase in production capacity, the shutdown of a number of smaller plants, and a reduction in manufacturing costs. Capacity tripled in the period from about 1958 to 1968. 

A summary of ammonia production and idle capacity for various regions is shown in Figure 3.11. Asia is the largest producer of ammonia and had the... 

Figure 3.11. 2003 World ammonia production idle capacity. (Reproduced by permission of Fertecon)...

Two effects cause the low production capacity of large-grained catalyst. First, large grain size retards transport of the ammonia formed inside the catalyst into the bulk gas stream. This is because the ammonia transport proceeds by slow diffusion through the pore system. The second effect is a consequence of the fact that a single catalyst grain in the oxide state reduces from the outside to the interior of the particle. The water vapor produced inside the catalyst by reduction comes into contact with already reduced catalyst on its way to the outer surface of the catalyst. This induces a severe recrystallization. As an example, if the particle size increases from about 1 to 8 mm, the inner surface decreases from 11 to 16 m2/g to 3 to 8 m2/g74. Therefore the choice of catalyst requires the optimization of 1) catalyst size versus catalyst activity, 2) catalyst size versus pressure drop across the converter and 3) the impact of 1 and 2 on... 

Ammonia production requires storage facilities to smooth over fluctuations in production, usage and shipments. Ammonia is stored in bulk in large capacity containers installed above or below ground. It is distributed to point of use almost exclusively as a liquid. Gaseous ammonia sometimes is used within plants74. 

Ammonia is the second largest synthetic commodity manufactured by the chemical industry, with the global production capacity exceeding 140 million metric tons. Haber, in 1909, demonstrated that ammonia can be produced at a high pressure by the reaction... 

Therefore, it is not surprising that currently about 70% of the world ammonia capacity is based on obtaining hydrogen from natural gas reforming. Of course, the economic analysis of various raw materials used for ammonia production is not complete without considering their relative price and availability which could ultimately dictate the choice for a particular feed. 

Also at times, political factors enter into the choosing of a particular feedstock for ammonia production. Table 2 shows the approximate breakdown of the current world ammonia capacity according to the feedstocks used. The data were derived from SRI s "World Nitrogen" report. CiL)... 

PROCESS TABLE 5. ESTIMATED AMMONIA PRODUCTION COSTS 1150 STPD CAPACITY STEAM REFORMING PARTIAL OXIDATION ... 

By 2002 30 percent of North American ammonia production was curtailed, and in 2004 four more plants were shut down. Although periodic downtimes of plants are not uncommon, the combination of import competition that depressed prices and very high feedstock costs in many industrialized countries has resulted in shutdowns of high-cost plants which resulted in a decline in world capacity.38,57 299... 

Table k22 shows the uses of ammonia in 1984 in Western Europe the United States, Japan and the world, as well as production, capacities and consumption for these geographic areas. Capacities ore also given for 1986. 

The production capacity for acrylonitrile (C3H3N) in the United States is over 2 million pounds per year. Acrylonitrile, the building block for polyacrylonitrile fibers and a variety of plastics, is produced from gaseous propylene, ammonia, and oxygen ... 

Two effects cause the low production capacity of coarse-grained catalyst first, large grain size retards transport of the ammonia from the particle interior into the bulk gas stream, because this proceeds only by slow diffusion through the pore system. Slow ammonia diffusion inhibits the rate of reaction. At the high reaction rate typical for the converter inlet layer, only a surface layer of the catalyst grains, about 1-2 mm thick, participates in the reaction. 

In practice, the reduction temperature is raised stepwise by using the exothermic heat of ammonia formation. The progress of the reduction is controlled according to the catalyst temperature and the water concentration by adjustment of the synthesis gas flow. As a rough guideline, the water content of the gas effluent from the catalyst should not exceed 2-3 g/m3 (STP). Under these conditions, depending on its size and operating pressure, a synthesis converter with a fresh load of oxidic catalyst attains its full production capacity in 4-10 d. 

The influence of the reduction conditions (gas flow rate, temperature in the range 300-600 °C, nitrogen content in the hydrogen in the range 0-100%) on the production capacity of an ammonia catalyst has been investigated [352]. 

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