Ashkon Poruheidary
Chemistry Summative Project
What is Ammonia?
Ammonia is a molecule consisting of Nitrogen and Hydrogen, covalently bonded with and bond angular
of 107, with formula of NH3. This colourless has contributes significantly to the nutritional and
pharmaceutical needs of people around the world. Have you ever asked yourself that with 6.92 billion
people living on earth, how does the food production industry is able to feed all of the people?
Ways of Production:
Two main types of production process for ammonia synthesis gas are currently in operation in Europe: Steam reforming of natural gas or other light hydrocarbons (Natural Gas Liquids, Liquefied
Petroleum Gas, Naphtha)
 Partial oxidation of heavy fuel oil or vacuum residue
About 85% of world ammonia production is based on steam reforming process.
Steam reforming of natural gas:
1. The first step in the process is to remove sulphur compounds from the feedstock because
sulphur deactivates the catalysts used in subsequent steps. Sulphur removal requires catalytic
hydrogenation to convert sulphur compounds in the feedstocks to gaseous hydrogen sulphide:
H2 + RSH → RH + H2S (gas)
2. The gaseous hydrogen sulphide is then absorbed and removed by passing it through beds of zinc
oxide where it is converted to solid zinc sulphide:
H2S + ZnO → ZnS + H2O
3. Catalytic steam reforming of the sulphur-free feedstock is then used to form hydrogen
plus carbon monoxide:
CH4 + H2O → CO + 3H2
4. The next step then uses catalytic shift conversion to convert the carbon monoxide to carbon
dioxide and more hydrogen:
CO + H2O → CO2 + H2
5. The carbon dioxide is then removed either by absorption in aqueous ethanolamine solutions or
by adsorption in pressure swing absorbers (PSA) using proprietary solid adsorption media.
6. The final step in producing the hydrogen is to use catalytic methanation to remove any small
residual amounts of carbon monoxide or carbon dioxide from the hydrogen:
CO + 3H2 → CH4 + H2O
CO2 + 4H2 → CH4 +2H2O
7. To produce the desired end-product ammonia, the hydrogen is then catalytically reacted with
nitrogen (derived from process air) to form anhydrous liquid ammonia. This step is known as the
ammonia synthesis loop (also referred to as the Haber-Bosch process):
3H2 + N2 → 2NH3
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The Connections to Chemistry 12 Course:
1. The role of Catalysts
The catalyst has no effect on the position of chemical equilibrium; rather, it provides an alternative
pathway with lower activation energy and hence increases the reaction rate, while remaining chemically
unchanged at the end of the reaction. The first Haber–Bosch reaction chambers
used osmium and ruthenium as catalysts. However, under Bosch's direction in 1909, a much less
expensive iron-based catalyst was discovered that is still used today. Part of the industrial production
now takes place with a ruthenium rather than an iron catalyst because this more active catalyst allows
reduced operating pressures.
2. Le chatelier’s Principle:
The ammonia production reaction is an exothermic reaction, thus heat releases as the reaction
proceeds. Le chatelier’s Principle predicts that the yield of ammonia is greater at lower temperature.
This way there is more ammonia produced. However, this would make another problem; low
temperature would decrease the rate of the reaction. This is crucial when we examine the profits of the
company producing ammonia. Le chalier’s principle also predicts that the yield of ammonia is greater at
higher pressures. High pressure platns are expensive to build and maintain, however.. Modern plants
operate at pressures in the range of 20,000 kPa to 30,000 Kpa.
3. Effects of Pressure on Rate of Reaction
the effects of pressure on rate of reaction comes into the action, at high pressure, the rate of reaction
will increase according to the collision theory, the high pressure would cause more successful collisions,
therefore the rate of reaction would be increase.
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