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