Ammonia production technology

It is difficult to venture a prognosis for the future development of ammonia production technology. As about 85% of the ammonia consumption goes into the manufacture of fertilizers, it is obvious that the future of the ammonia industry is very closely bound up with future fertilizer needs and the pattern of the world supply. 

Natural gas will remain the preferred feedstock of present ammonia production technology in the medium term (15-20 years) as may be assumed from the world energy balance shown in Table 47. Partial oxidation of heavy hydrocarbon residues will be limited to special cases and coal gasification might not play a major role in this period. 

M. Appl, The Haber-Bosch Heritage The Ammonia Production Technology" 50th Anniversary of the IFA Technical Conference, September 25-26, 1997, Sevilla, Spain. 

Dybkjaer, I., Development in ammonia production technology—Historical review. Nitrogen 91 International Conference Preprints, Copenhagen, Denmark, June 4—6, 1991. 

Nielsen, S.E. (Latest Developments in Ammonia Production Technology, p. 1-14, FAI International Technical Conference on Fertiliser Technology, April 12-13, 2007, New Delhi. 

In the foregoing sections the individual process steps involved in the production of ammonia from various feedstocks have been described. However, it is very important how these building blocks are combined with each other, and with the steam and power systems, to form a complete facility for the production of ammonia. The way this is accomplished has a major impact on plant efficiency and reliability, and much of the difference between the several ammonia processes and much of the development in ammonia production technology may today be found in these areas. It may be said that while Ammonia Technology was in the early days of the industry most often understood as Ammonia Synthesis Technology or even Ammonia Converter and Catalyst Technology , it is today interpreted as the complete technology involved in transformation of the primary feedstock to the final product ammonia. 

Dybkjaer, I. 1990. Advances in ammonia production technology. Lyngby Haldor Topsoe Dybkjaer, I. 1992. Large ammonia plants design and operating experience. Paper presented at the 1992 IFA-FADINAP Regional Conference for Asia and the Pacific, Bali, November 30-December 2, 1992. 

The technology of urea production is highly advanced. The raw materials requited ate ammonia and carbon dioxide. Invariably, urea plants ate located adjacent to ammonia production faciUties which conveniently furnish not only the ammonia but also the carbon dioxide, because carbon dioxide is a by-product of synthesis gas production and purification. The ammonia and carbon dioxide ate fed to a high pressure (up to 30 MPa (300 atm)) reactor at temperatures of about 200°C where ammonium carbamate [111-78-0] CH N202, urea, and water ate formed. 

Coal is expected to be the best domestic feedstock alternative to natural gas. Although coal-based ammonia plants have been built elsewhere, there is no such plant in the United States. Pilot-scale projects have demonstrated effective ammonia-from-coal technology (102). The cost of ammonia production can be anticipated to increase, lea ding to increases in the cost of producing nitrogen fertilizers. 

Even though form amide was synthesized as early as 1863 by W. A. Hoffmann from ethyl formate [109-94-4] and ammonia, it only became accessible on a large scale, and thus iadustrially important, after development of high pressure production technology. In the 1990s, form amide is mainly manufactured either by direct synthesis from carbon monoxide and ammonia, or more importandy ia a two-stage process by reaction of methyl formate (from carbon monoxide and methanol) with ammonia. 

The mature Haber-Bosch technology is unlikely to change substantiaHy in the foreseeable future. The centers for commercial ammonia production may, however, relocate to sites where large quantities of natural gas are flared from cmde oil production, eg, Saudi Arabia or Venezuela. Relocation would not offset the problems for agriculture of high transportation and storage costs for ammonia production and distribution. Whereas the development of improved lower temperature and pressure catalysts is feasible, none is on the horizon as of this writing. 

The importance of size on the economics of ammonia production can be seen from Figure 3-1 and Table 3-4, which was developed in 1967 by G. Russell James, general manager of Chemical Engineering Associates (Armonk, N.Y.)4 Before 1969, a 400-tons-per-day plant was large. Now it can barely compete even if it is updated technologically. 

Future Considerations in Ammonia Production. In addition to continued emphasis on energy efficiency, alternate feedstocks will continue to be a primary area of ammonia technology. 

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. 

Methanol synthesis resembles that of ammonia in that high temperatures and pressures are used to obtain high conversions and rates. Improvements in catalysts allow operation at temperatures and pressures much lower than those of the initial commercial processes. Today, low-pressure Cu-Zn-Alminium oxide catalysts are operated at about 1500 psi and 250°C. These catalysts must be protected from trace impurities that the older high-pressure (5000 psi and 350°C) and medium-pressure (3000 psi and 250°C) catalysts tolerate better. Synthesis gas production technology has also evolved so that it is possible to maintain the required low levels of these trace impurities. 

Due to several major developments in ammonia process technology, ammonia plants with 1000 to 1500 tonne per day capacities have became the industry standard for new plant construction. In 2001 plants as large as 2000 tonnes per day have become common. These plants have much lower production costs than the earlier generation of smaller plants mainly because steam-driven, centrifugal compressors are used rather than electrically driven, reciprocating compressors.57,74... 

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-... 

The previous sections mainly considered the individual process steps involved in the production of ammonia and the progress made in recent years. The way in which these process components are combined with respect to mass and energy flow has a major influence on efficiency and reliability. Apart from the feedstock, many of the differences between various commercial ammonia processes lie in the way in which the process elements are integrated. Formerly the term ammonia technology referred mostly to ammonia synthesis technology (catalyst, converters, and synthesis loop), whereas today it is interpreted as the complete series of industrial operations leading from the primary feedstock to the final product ammonia. 

Natural gas is by far the most economical feedstock for ammonia production, achieving the lowest energy consumption and requiring the lowest investment [404], This can also be seen from Table 45, which gives an estimate of ammonia production costs in Northwest Europe for different feedstocks using state-of-the-art technological standards. The lump turn key price for the ammonia plant were assumed as 180 x 106 for steam reforming of natural gas, 270 x 106 for partial oxidation of vacuum residue and 400 x 106 for coal-based plants (Capacity 1800 mt/d). 

M. Appl Ammonia, Methanol Hydrogen, Carbon Monoxide — Modern Production Technologies. CRU, London 1997. 

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