How Adipic Acid is Produced ?

PROCESS DESCRIPTION

REACTOR 1

Cyclohexane on oxidation gives cyclohexanol and cyclohexanone(alcohol and ketone) with

20% cyclohexane remains unreacted.

Unreacted(excess) Oxygen  is drawn out from the product.

DISTILLATION COLUMN

The mixture obtained at the outlet of reactor 1 is introduced in the distillation column where distillate consists of cyclohexane and water  is completely removed.

K.A mixture consisting of ketonic,alcoholic group and water is the bottom product

REACTOR 2

The K.A mixture is oxidized in the presence of nitric acid as oxidizing agent.

This oxidation results into the formation of 94% adipic acid alongwith Nox,salicylic acid ,gluteric acid(as by products),water and excess HNO3.

Nox REMOVAL

FLASH DRUM

The product from reactor 2 is then expanded from high pressure due to which Nox are separated from mixtue.

The Nox are then absorbed in Absorber.

ABSORBER

Absorber is used to  convert the oxides of nitrogen into Nitric acid.

Air is introduced alongwith  water to form Nitric acid in two steps.

STEP 1:

Formation of NO2 from NO

STEP 2:

Formation of Nitric  acid by reaction of water and NO2.

VACUUM DISTILLATION

For Enhancing the concentration of  Adipic acid upto 95%.

CRYSTALLIZER

Upto 98% purity of adipic acid is achieved.

Crystals of Adipic acid are obtained with small amount of mother liquor(HNO3,Gluteric acid and salicylic acid).

CENTRIFUGE

The mother liquor is separated from crystals here by adding water.

The crystal is washed  by water.

The excess water is then removed by dryer.

DRYER

Dryer is used to remove the water used for washing away the  mother liquor.

If water removal is not done then the crystal may remain impure and cause brittlness,not suitable  for handling and transportation.

 

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