Chemical Process Industry -

Bulk Gases
Chemical Process Industry
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Gas Applications in the Chemical Process Industry

The most common, but frequently misunderstood, applications requiring industrial gases within the Chemical Process industry are blanketing, inerting, and purging. Many people use these three terms interchangeably, yet each one refers to a very specific operation or intent.

The volumes associated with these applications can be significant at larger chemical plants and refineries. An applications engineer can assist the customer to determine an acceptable purity level to ensure both product quality and safe operation.

For some customers, these applications are best served by bulk supply of cryogenic liquid. Small customers or those that have wide swings in demand for gas fall into this category.


Inerting is the process of converting from flammable or reactive conditions into a safe non-flammable state by the addition of an inert fluid (usually nitrogen). Combustion can take place provided three components are present simultaneously and in the right amount. These components are:
•Source of ignition - friction, heat, electrical discharge, or flame

The right amount for combustion means that the concentrations of fuel and oxygen must be within the region of flammable mixtures and the ignition energy must be sufficiently large enough to initiate combustion.

The most common way of characterizing the flammability of fuels and their tendency to explode is by using the flammability limits in air. Replacing the air with nitrogen removes the Oxygen component, thus allowing for a safe, non-flamible atmosphere.


Blanketing is the process of maintaining a steady state of conditions with an inert gas above the product. Blanketing is done to prevent a product from catching fire, discoloring, polymerizing, or degrading (e.g. bad odors or taste). There are several methods to assure a safe atmosphere by blanketing a product. These very in capital and operating costs. Let Airgas work with you to determine the safest, most efficient and cost effective system for your blanketing requirements.


Purging is the process of adding a substance to an open system or releasing it, to go from one concentration to another, be it moisture, oxygen, or product purity. Purging a system to an inert state will render it safe from combustion or explosion as long as the inert state is maintained by blanketing.

The two main situations encountered in purging a chemical process include:
•Start up, where equipment containing air is to be placed into service
•Shut down, where equipment containing combustible gas or vapor is to be withdrawn from service

In general, we recommend between 3 to 5 tank volume changes of cryogenic-purity grade inert gas in order to achieve a safe atmosphere. Our application engineers can assist with the number of purge volumes needed to ensure a safe operating condition.

Sparging & Stripping

Sparging is the process of adding gas as fine bubbles to a process liquid in order to increase the rate of biological or chemical reaction by improving the available surface area between the two phases. Stripping is the process of adding gas as fine bubbles to a process liquid in order to adsorb a component from the liquid.

Carbon dioxide is used in sparging applications such as waste water pH control. Nitrogen is used in stripping applications such as removing oxygen from oil or waste water to promote anaerobic activity, or in sparging applications such as wine production.

Our fine bubble diffusion sparger introduces gas into the process with the convenience and flexibility of being able to remove the sparger from the process at any time without bringing production down.

Vapor Emission Control

Airgas Customer designed Vapor Emission Control systems remove volatile organic compounds (VOC) from process gases through cryogenic condensation technology.

Cryogenic condensation technology is most suitable for process gases with a VOC concentration of 1% or higher and a flow rate of 500 scfm or lower. The higher the concentration and/or lower the flow rate, the more economical the technology becomes. The equipment is reliable, repeatable, and typically offers VOC removal efficiencies of 99+%.

Reactor & Fluid Chilling

The Airgas Fluid Temperature Control (FTC) System is an extraordinary heat exchanger system that eliminates the freezing problems normally associated with cryogenic cooling systems.

The technology is an excellent choice for applications requiring ultra-low cooling. Examples include improving yields on chiral reactions, crystallizations, and distributed cooling loops.

Low capital equipment and installation expenses make the system quite cost effective. The system's rapid cool down times and precise accuracy minimizes the operating costs related to liquid nitrogen. Operating costs become especially low -- and are sometimes eliminated -- when one can reuse the pure gaseous nitrogen effluent from the system. We also offer rental and lease-to-own options to help improve the system's affordability or those with short-term production campaigns.