A. AMMONIA AND UREAAmmonia is the s

A. AMMONIA AND UREA
Ammonia is the second largest chemical product produced in the world, behind sulfuric acid. The demand for ammonia is driven by the demand for fertilizers. Of the world’s nitrogen demand, 85% is for fertilizer primarily derived from ammonia in the form of:
 Urea
 Ammonium nitrate
 Phosphate
 Sulfate
Other uses of ammonia include fibers, resins, refrigeration, and pulp and paper industries.
Ammonia can be produced from different hydrocarbon feedstocks such as natural gas, coal, and oil. Natural gas accounts for more than 95% of ammonia tonnage. Natural gas is the preferred feedstock primarily because:
It is intrinsically the most hydrogen rich and, therefore, contributes more hydrogen compared with other feedstocks on a unit weight basis.
The heavier feedstocks, like coal and oil, are more complex to process; therefore, the capital costs are higher compared to natural gas.
In year 2000, ammonia was a 131 million metric tons per year industry. Worldwide annual growth is anticipated to be approximately 1.6 to 2%. Urea is a 107 million metric tons per year industry directly derived from ammonia. The end uses for urea are:
 Fertilizers
 Formaldehyde-urea resins
 Plastics
 Fibers
 History
The first commercial ammonia plant was commissioned in the early 20th century on the basis of the fundamental research work of Haber. Bosch and his engineering team developed the ammonia-synthesis process with a promoted iron-based catalyst. Since then, there has been no fundamental change in the ammonia-synthesis reaction itself. A mixture of hydrogen and nitrogen reacts on the iron catalyst at elevated temperatures in the range of 400 to 500°C operating at pressure above 100 bar.
3H2 + N2  2NH3
The unconverted part of the synthesis gas is recirculated (after the removal of ammonia) and supplemented with fresh synthesis gas to compensate for the amount of nitrogen and hydrogen converted to ammonia. The production of ammonia synthesis gas, consisting of pure hydrogen and nitrogen, is the largest single contributor of the production cost of ammonia. Hence, in contrast to the ammonia-synthesis section, dramatic changes have been made over the years in the technology for the generation of synthesis gas. Net energy consumption has been reduced progressively, from approximately 88 GJ/ton ammonia in the days of coke-based water-gas generators to approximately 28 GJ/ton ammonia today with the use of natural gas in a steam reforming unit.