Silica Gel in Drying
of Gases
While Silica Gel is mostly
known for removing humidity from packed spaces, it has various other uses as
well. One of the important uses of Silica Gel is in the successful removal of
moisture molecules from gases and liquids. Both of these are very vulnerable to
moisture and are greatly affected by it. Companies working in the gas and liquid
field make wide use of Silica Gel sachets to keep humidity at bay. Utmost care
should be taken that there are no traces of moisture in gases/liquids as it
adversely affects their use and movement from one place to another.
All over the world, Silica
Gel is the first choice to remove moisture from gas and liquid streams. This is
due to two factors- 1) large surface area of the Silica Gel molecules and 2)
high rate of absorption. These characteristics help Silica Gel desiccant absorb
more humidity in lesser time from natural gas and various other industrial
gases. Silica Gel desiccant is also widely used in the hydrocarbon recovery
process and the mass dehydration of compressed air.
Blue & Orange
Indicating Silica Gel in Gas Drying
Based on its ability to absorb
moisture, Silica Gel is divided into different categories/grades. It can be
classified into Indicating (changes colour) and Non-Indicating (no colour
change). The Indicating Silica Gel, in turn, can be found in Blue, Orange, Pink
colours. These change colour when they become completely saturated with
moisture. Blue and Orange grades of Indicating Silica Gel are mainly used to
remove moisture molecules present in air/gases. This is applicable for both the
static as well as dynamic situations. The colour change in both Indicating
Silica Gel types will let one know when the Silica Gel adsorbent becomes fully
saturated and when it needs to be replaced.
Silica Gel Orange
Orange Indicating Silica
Gel packets change into dark green and becomes colorless as well. In the first
case, the Silica Gel packets change color from a very bright orange (a dry
state) to a dark green ( nearing saturation). When the Orange Indicating Silica Gel packets turn completely green, then it is understood that it can no longer
absorb any more moisture.
Silica
Gel Orange is known to contain iron salts
and changes colour from a deep orange (dry state) to a colorless state, when all
the moisture has been already absorbed. Orange Indicating Silica Gel packets
are available as granules and beads.
Silica Gel Blue
Blue Indicating Silica Gel Packets contain cobalt and is
sometimes considered poisonous. The Blue Indicating Silica Gel desiccant
changes color from blue to pink, going from a dry state to a fully saturated
state. It is available in 2 or 3-6 mm granular forms.
