6.2. Protective atmospheres processing on the basis of liquefied nitrogen


Equipping of small capacity units for material  thermal-chemical treating by the gas-plant for  protective atmospheres production – dry explosion-proof nitrogen-hydrogen mixtures. 

Description and development composition

Protective atmospheres are produced on the basis of liquefied nitrogen and liquid ammonia – is a source of hydrogen. One  ammonia cylinder contains in 9 times more of hydrogen than hydrogen cylinder with pressure 15 Mpa. Ammonia is dissociated before hydrogen-ammonia mixture receiving.   

The main compounds of gas-plant: ammonia manifold,  ammonia cracker with output till 0,5 m3/h, the reactor of oxygen neutralization in nitrogen-oxygen mixture, dewatering unit. Oxygen concentration in mixture is not exceeded 0,002%, Н20 – 0,012-0,04%,  dew point is –30 – -40°C.


Gas-plant for  protective atmospheres production can be used during the sintering process of manufacture from metal powder and during thermal treatment of manufacture from steel and alloys on the basis of iron.