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Producing Ammonia - Reducing the Cost
Like most chemical reactions, the production of ammonia has to
overcome an activation energy for the reaction to start.
The activation energy for the production of ammonia is
relatively high, and this would normally be
overcome by an initial high temperature.
An initial high temperature would
increase the cost, whereas the use of a
catalyst would minimise the cost.
Iron is used as a catalyst in the Haber Process.…read more

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The Effect of the Iron Catalyst
Catalysts often have the effect of lowering activation energy
levels in many chemical reactions and industrial processes.
This allows a reaction to proceed more efficiently, and at lower
temperatures and pressures than would be possible in the
absence of a catalyst.…read more

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The Effect of the Iron Catalyst
Catalysts often have the effect of lowering activation energy
levels in many chemical reactions and industrial processes.
This allows a reaction to proceed more efficiently, and at lower
temperatures and pressures than would be possible in the
absence of a catalyst.…read more

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Producing Ammonia - The Problem
However, ammonia has relatively weak bonds between the
nitrogen and hydrogen, and so a higher temperature increases the
rate of dissociation of ammonia back into nitrogen and hydrogen.
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In addition, the reaction is exothermic, and to maximise the yield,
the temperature must be carefully controlled.
Industrial chemists control variables such as pressure and
temperature (both affect the balance of the dynamic equilibrium)
so as to make the reaction proceed efficiently and produce the
greatest yield of ammonia.…read more

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Producing Ammonia - Pressure
Higher pressures favour the forward reaction, converting a
greater proportion of nitrogen and hydrogen into ammonia than
ammonia into nitrogen and hydrogen.
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However, even though increasing the pressure increases the yield,
a higher pressure increases the design, building and maintenance
costs of the industrial plant.
The cost of the plant must be taken into account when deciding
upon the most economical conditions for ammonia production.
Pressures between 200 - 1,000 atmospheres are suitable, with
500 atmospheres being the most common pressure used.…read more

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