The Chemical Synthesis Process of Ammonia
(The Haber Process)
Availability of reagents
nitrogen
Higher availability
hydrogen
more yield, more efficient
Available in the air
makes up 78% of air #
Carbon monoxide removed
Methane (CH4) + Steam
hydrogen produced
reacts with oxygen from air
leaving nitrogen for use
carbon monoxide - bi product
Stoichiometric Ratio
H2 : N2
1:3
Excess of Nitrogen
Hydrogen is limiting reagent
Avogadro's Law
Equal volume of gas
Equal volume
Equal molecules
ratio of 1:3
Excess reagent
no impurities (sulfur)
wastes space
not efficient
1:3
What is the it?
Developed 1915
Combination of nitrogen and hydrogen
produce ammonia (NH3)
hydrogen
from air
nitrogen
from natural gas
after hydrogen reacts with oxygen #
reaction
Stoichiometric ratio H2:N2
3:1
exothermic reaction
Reversible (eqilibrium reaction)
Production of ammonia
reaction of hydrogen + nitrogen in pump
high pressure (200 atm)
compressed and then heated (400-450 degrees)
contact with catalyst
iron oxide (Fe3O4)
mixed with potassium hydroxide
increase rate of reaction
does not effect reaction whatsoever
react forming ammonia
cooled down
ammonia is liquified
unreacted gasses
remain in gaseous form
recycled back into pump along with heat
repressurised
drained and collected
factors when making
efficiency
availability
conditions
costs
pressure
temperature
catalyst
reactant
pipes
pumps
heat
Reaction conditions
Catalyst
lets lower temperature usable
no effect on reaction or yield
increases rate of reaction
decrease activation energy
enough energy for reaction
assists in reaching dynamic equilibrium
Fe3O4 iron oxide (magnetite)
mixed with potassium hydroxide
increase efficiency of reaction
powdered form
increased surface area
increased collision
collision theory
pressure
optimal pressure
200 atm
costs (expensive)
difficult to maintain
increased pressure
Le Chateliers's Principle
increases concentration
increases chance of collision #
increases yield #
favours reaction with less molecules
Temperature
optimal temperature
400-450 degrees celcius
not too high not too low
sufficient yield
10-20%
produces most ammonia in short time
High temperature #
Increases rate of reaction
favours reactant side #
decrease in yield
Low temperature
decreases reaction rate
reaction too slow
cannot reach equilibrium
increase yield
exothermic #
Yield and Purity
yield
optimal conditions for reaction #
temperature
pressure
catalyst
400-450 degrees #
200 atm #
powdered iron oxide #
maximise yield in short time
15%reacts to form ammonia
unreacted gas recycled
with heat
Putiry
unwanted chemicals (impurities)
carbon monoxide
sulfur
carbon dioxide
carbon monoxide, carbon dioxide and sulfur are removed
issues/implications
environmental
positive
used as fertilisers
increase fertility of plants
During WW1
ammonium sulfate
ammonium nitrate
better agriculture
increased food for humanity
sustain global food production
negative
released into the air
acid rain
heavy rainfall
fertiliser released into waterways (lakes and rivers)
changes pH of water
affect aquatic life
destroys habitat #
eutrophication
aquatic plants grow too fast
grow big and decay
decayed plant covers smaller plant
no sunlight no photosynthesis
smaller plant dies too
aerobic bacteria (oxygen for survival)
eat decayed plants and grow bigger
consume more oxygen
less oxygen in lake/river
fishes die #
social
positive
produce other chemicals
pharmaceutical products
household products
cleaning products
fertilizers
fertilizers
assist sustaining food globally
nutrients for plants
negative
leaked ammonia/fertilizers
affects aquatic organisms
destroy fishing industry
less fish to catch
Economic
positive
maximised yield
best reaction conditions #
high efficiency
exothermic
heat can be recycled #
iron catalyst has a long life cycle
can be reused multiple times
high demand for agriculture
economic profits
negative
greenhouse gas emmision
climate change
very high costs
strong pipes
withstand pressure
maintain pressure in reactor
cost of heat
can be reduced #
maximise yield
production of hydrogen
industrial uses
produce other chemicals
fertilisers
ammonia sulfate
ammonia nitrate
used for sustaining food globally
household cleaners
nitric acid
dyes
starter for explosives
plastic
feedstock