Nitrogen Products

Ariziel Ruth D. Marquez

AMMONIA

• Once called “Spirit of Hartshorn”

• Chemical Formula is NH3

• Uses: 1. Fertilizers

2. Manufacture of fertilizers and other nitrogen compounds like nitric acid and nitrates

3. Refrigerant

4. Manufacture of explosives

AMMONIA • Common manufacturing process: Haber Process by

Haber Bosch in 1913.

▫ N2 + 3H2 2NH3, a reversible and exothermic process)

▫ To favor forward reaction: a. low temperature of 500oC

b. High pressure of 200 atm c. Use catalyst such as Fe with oxides of Al, K and Fe

▫ This yields a n 8% to 10% conversion

▫ Sources are Air (destructive distillation to produce N2), water and hydrocarbons

AMMONIA

• Steps in the manufacture of NH3

▫ Production of reactant gases

▫ Purification of reactant gases (CO is removed since it will poison the catalyst)

▫ Compression

▫ Catalytic conversion

▫ Recovery of NH3 : a. Liquefaction

b. Absorption

(NH3 + H2O NH4OH)

▫ Recycling

FLOW CHART

Converter Condenser

Compressed H2 & N2

Recycle

NH3, H2 N2

Product NH3

NITRIC ACID

• Common name: Aqua fortis

• Chemical Formula: HNO3

• Uses: 1. Manufacture of explosives

2. Preparation of inorganic nitrates and fertilizers

3. Metal pickling

4. Separation of gold and silver

NITRIC ACID

• Manufacturing process ▫ Batch process (Pot still process)

(H2SO4 + NaNO3 NaHSO4 + HNO3)

▫ When the reaction ceases, the pot still may be emptied and another batch of the feed will be charged.

Niter cake

cooler

HNO3 Reactant

Pot Still

NITRIC ACID

• Manufacturing process ▫ Continuous process (Ostwald process) The raw feed is a mixture of ammonia and air. A mixture

of about NH3 is mixed with 10 volumes of compressed air is heated at 600 – 700oC and is then fed to a converter using Pt as catalyst.

(4NH3 + 5O2 4NO + 6H2O : ammonia oxidation)

The remaining O2 is then used to oxidize the NO to NO2. (NO + 1/2 O2 NO2)

The nitrogen dioxide is then cooled and absorbed by water.

(2NO2 + H2O 2HNO3 + NO)

NO is then mixed with air again to be oxidized to NO2.

The overall reaction: NH3 + 2O2 HNO3 + H2O

FLOW DIAGRAM

Burner Converter Charge

1o Air

Burner Gas

Converter Gas

ABSORBER

Absorbing medium

Absorber Gas

Product