Drying, Inerting, Blanketing & Purging

Protect Chemicals in Storage and Pipelines
Inert gases effectively protect chemicals in storage and pipelines against oxygen and moisture, giving you improved safety, controllability and quality
Air bubbles
Drying and Purging

Our industrial service portfolio includes drying with nitrogen (N2) gas. This involves pumping N2 at high flow rates, pressures and temperatures through your process system to dry and purge it. The low dew point of N2 (-67.8°C or -90°F) makes this an efficient way to remove moisture from process systems, saving you time and money. We also provide N2 to safely purge potentially explosive hydrocarbon and air mixtures from vessels, gas lines, transfer lines and equipment. In some regions, this service is available as a complete problem-solving package including maintenance and operation by our staff.

Our refinery turnaround portfolio includes a dry air all-inclusive service in certain geographies. This can be an attractive alternative to drying process systems as it delivers 100% oil-free air at dew points as low as -67.8°C (-90°F) using multi-bed desiccant dryers. Contact your local Linde representative to check what services are available in your area.

Inerting for Safe Storage of Chemicals

Atmospheric oxygen and moisture can compromise the safe storage of valuable chemicals, particularly in the case of highly volatile substances or products prone to oxidation. Inerting or blanketing can help overcome this problem by displacing air and moisture. Inerting involves injecting pure, dry nitrogen (N2) into a chemical vessel’s headspace to prevent oxidation or moisture contamination. The N2 gas forms a protective, safe layer of gas over the contents of the tank or reactor.

Gases such as N2 and carbon dioxide (CO2) can also be used to create a protective blanket in storage tanks and vessels containing flammable liquids or solids to prevent fire or explosion. Blanketing maintains a safe and dependable inert layer of gas on top of the substance or in the empty spaces in a vessel. CO2 and N2 can also be used to maintain a dry inert atmosphere in industrially cleaned piping and vessels to avoid corrosion.

As a leading supplier of the inert gases N2 and CO2, we also have the know-how to help you select and size the equipment you need for safe, effective inerting and blanketing.

Purging to Replace Vessel Volume with Inert Gas

Purging is an inerting method commonly used in safety-critical process vessels such as reactors to eliminate oxygen and moisture when operations are started up or shut down. The three primary methods are displacement, dilution and vacuum purging. With displacement purging, an inert gas is injected into an open vessel to displace atmospheric air. Dilution purging involves injecting an inert gas to reduce the concentration of oxygen and moisture. In the case of vacuum purging, air is extracted with a vacuum pump and an inert gas is then fed into the evacuated vessel. Purging is also used to remove air from piping systems.

In addition, purging can be used to dispel flammable or poisonous gases. Purging is typically an initial step used to prepare a vessel before maintaining an inert atmosphere in the headspace.

Our experts can advise on the purging setup best suited to your operational challenges.

Pressure Transfer of Liquids with Inert Gases

Conventional methods used to transfer reactants from one vessel to another present a number of challenges. They often require special pump designs, compatible with the wide range of fluids which need to be transferred. In addition, even small failures of seals, especially on the suction side of the pump, can result in leakage of air or other ambient vapors into the fluid stream. In the case of high-quality synthesis reactions, such impurities can lead to product rejections. In addition, rotating equipment like pumps requires ongoing maintenance and can be prone to failure, which can be very disruptive to chemical production operations.

Pressure transfer using pure dry inert gases like nitrogen offer a simpler and safer alternative to pumping. Pressure transfer does not require any rotating equipment and is therefore more reliable. The rate of liquid transfer can be regulated by controlling the gas flow rate and pressure. We have years of expertise in the proper specification of pressure transfer systems and components.

Close-up of nitrogen piping including control valve

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