Nitrogen generators cut corrosion

Parker Balston has developed a range of nitrogen generators that eliminate the problems associated with pipework and tank corrosion in industrial and horticultural applications.

Oxygen is necessary for every form of life, but its presence also causes decay and oxidation.

When water is present as well as oxygen, the combination can cause metal tanks and pipework to corrode - sometimes with catastrophic consequences.

Tank blanketing is a technique for applying a cover of gas over the surface of a store commodity - usually a liquid - to prevent combustion or degradation.

Hot water tanks can employ blanketing to prevent corrosion of copper and iron, bacterial growth and dust ingress.

A great many liquids, or powders, can be blanketed including adhesives, chemicals, fats and oils, foods, fuels, inks, soaps and water.

Parker Balston has developed a range of nitrogen generators that eliminate the problems associated with pipework and tank corrosion in industrial and horticultural applications.

Parker Balston nitrogen generators can produce an on-site continuous flow of up to 4000Nm3/h (66,666 litre/min) at purity levels up to 99.5 %These generators use hollow fibre polymeric membranes to remove oxygen and water vapour from air to leave only nitrogen and small quantities of other inert gases.

The hollow fibre membranes separate the component gases in air by the selective permeation across the membrane wall.

When compressed air is applied to one end of a bundle of hollow fibres, separation takes place during the time that the compressed air remains within the fibre.

Nitrogen (which comprises 78.03% of the air) passes through the length of the fibre bundle, while oxygen and water vapour permeate the membrane wall.

The advantage of this technique is that there are no moving parts, and so little maintenance is needed.

The life expectancy of membrane systems can run into decades, and the only energy costs are those used to produce the compressed air (which in many cases is sourced from the central air line).

Nitrogen is colourless, odourless and tasteless.

It is used in a wide variety of industries but generally only for two purposes.

One is to prevent degradation of foodstuffs and chemicals due to atmospheric oxidation.

The other use is to enhance safety by preventing the possibility of combustion, for instance when solvents are being stored, or powders transported.

Nitrogen is therefore an ideal gas for covering the surface of liquids and powders stored in tanks.

Blanketing can prevent liquid from vaporising into the atmosphere and a blanketing system can be designed to make up the displacement volume caused by emptying liquid from the tank.

This volume would otherwise be replaced by atmospheric air, increasing the risk of degradation or explosion.

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