Silica Gel Desiccant | White Blue Orange Grades

SorbiTech Instrument Plant Air Drying Heatless Instrument Air Heatless Activated Alumina

Grades available 3 (White · Blue · Orange)

Water capacity above 35 percent at 60 RH

Regeneration 120 to 180 °C

Manufacturing ISO 9001:2015

Adsorbent Family · Manufactured to ISO 9001:2015

Amorphous silicon dioxide desiccant for compressed air drying, transformer breather service, and packaging desiccation.

The silica gel range covers three indicator chemistries on a single amorphous silicon dioxide carrier. White silica gel for industrial drying without colour change. Blue indicating silica gel impregnated with cobalt chloride, blue when dry and pink when saturated. Orange indicating silica gel impregnated with methyl violet, orange when dry and green when saturated. The orange variant is the cobalt free option preferred for European and pharmaceutical service.

Manufacturing uses sulfuric acid neutralisation of sodium silicate, controlled gel ageing, washing, drying, and sieving to the target particle distribution. The pore structure is set during gel ageing and confirmed by water vapour isotherm. Each lot is sampled for water capacity at 20 °C and 60 percent relative humidity, attrition loss, and bulk density before release.

In service the silica gel bed is the soft drying option, with capacity that ramps linearly with relative humidity and not with absolute water concentration. Regeneration is mild, between 120 and 180 °C, suitable for waste heat recovery and energy efficient dryer designs. The bed survives multiple cycles without loss of capacity if the regeneration temperature is held below 200 °C.

Mechanism

Capacity ramps steeply between 30 and 60 percent relative humidity, then saturates. The bed is sized by inlet humidity, not by outlet specification alone.

22 to 26 Ångström Pore centre

38 to 42 percent by weight Peak capacity

How It Works

Capillary Condensation Inside the Pore

Adsorption on silica gel proceeds by capillary condensation of water inside the gel pore network. The pore distribution is centred around 22 to 26 Å with a narrow spread, giving an adsorption isotherm that ramps steeply between 30 and 60 percent relative humidity. Below 20 percent the capacity is modest. Above 70 percent the capacity saturates around 38 to 42 percent by weight.

The mechanism explains the design rules for the dryer. Silica gel suits duties where the inlet humidity is high and the outlet specification is mild, such as instrument air drying to a pressure dew point above minus 40 °C. For deep drying below this dew point the equilibrium limit of silica gel is reached and molecular sieve becomes the correct choice.

SorbiTech Silica Gel White White Desiccant Instrument Air Drying — SorbiTech Manufacturing

Raw Material & Manufacturing

Manufactured by acid neutralisation of sodium silicate

The silica gel range is produced by SorbiTech by acid neutralisation of sodium silicate. Sulfuric acid is added to the silicate solution at controlled rate and temperature, precipitating amorphous silicic acid gel. The gel is aged in the mother liquor under controlled conditions to develop the target pore size distribution.

After ageing the gel is washed, dried at 110 to 150 °C, and screened to the bead or granular cut. The white grade ships as the base product. The blue indicating grade carries a cobalt chloride impregnation. The orange indicating grade carries a methyl violet impregnation for cobalt free service. Every lot is sampled at the QC laboratory for water capacity at 20 °C and 60 percent relative humidity, attrition loss, and bulk density.

Grades in the Family

Available Grades and Specifications

Each grade is a defined product with its own technical data sheet, certificate of analysis, and engineering selection guidance. Open a grade for the full specification, applications, and lifecycle service notes.

Grade

Silica Gel Orange

Water cap.: ≥ 30 percent at 80 percent RH %
BET surface: 650–800 m²/g
Form: 2–5 mm beads
Bulk density: 0.72–0.78 g/ml

Cobalt free indicating silica gel for REACH compliant transformer breathers and packaged goods desiccation.

View Specifications

Grade

Silica Gel White

Water cap.: ≥ 30 percent at 80 percent RH %
BET surface: 650–800 m²/g
Form: 2–5 mm beads · 3–8 mm beads · fine 0.5–2 mm grade
Bulk density: 0.72–0.78 g/ml

Non indicating amorphous silica desiccant for compressed air drying and bulk packaged goods desiccation.

View Specifications

Grade

Silica Gel Blue

Water cap.: ≥ 30 percent at 80 percent RH %
BET surface: 650–800 m²/g
Form: 2–5 mm beads · 3–8 mm beads
Bulk density: 0.72–0.78 g/ml

Cobalt chloride indicating silica gel for transformer breathers and visual moisture monitoring.

View Specifications

Process Applications

Where This Family Is Specified

Representative process applications where the SorbiTech engineering team has scoped, sized, or supplied the bed. Each tile links to the full application page.

Heatless Instrument Air Drying

Compressed Air Final Polish

LPG and Propane Drying

Pharmaceutical Packaging

Why SorbiTech

Engineered media, supported through the bed life

The SorbiTech group covers media supply, engineering design, lifecycle service, and quality documentation under a single accountability. The bead and the bed are one decision.

Engineered, Not Traded

The grade shipped is the grade engineered into the vessel design. SorbiTech designs the dryer, sizes the bed, and supplies the media as one decision.

Lot Traceability per Shipment

Every shipment ships with a certificate of analysis covering iodine number, water capacity, crush strength, attrition loss, and bulk density measured against the lot.

Lifecycle Service Contract

The bed is supported through its service life. Field sampling, performance audit, reactivation logistics, and end of life return are covered under one service agreement.

Cross Disciplinary Team

Process engineers, mechanical designers, and lifecycle specialists work the same project. The recommendation closes against duty data, not against a catalogue page.

Engineering Guidance

Which Grade for Which Duty

Starting point for grade selection. The final specification is closed out after the SorbiTech engineering team receives duty data, inlet composition, and the target outlet condition.

Duty or Target

Recommended Grade

Industrial instrument air drying, dew point above minus 40 °C

White silica gel, bead form, 2 to 5 mm.

Transformer breather service with visible end of life indicator

Blue indicating cobalt chloride or orange indicating methyl violet, granular.

Pharmaceutical and food packaging desiccation

White silica gel, food and pharmaceutical grade, packaged in sachet or canister.

Outdoor electrical cabinet humidity control

White or indicating grade, loose fill, replaced or regenerated on schedule.

Polishing stage downstream of refrigerated dryer

White silica gel, bead form, sized to the air flow at peak ambient humidity.

Engineering FAQ

Common Questions on Silica Gel

When should I choose silica gel over molecular sieve?

Choose silica gel when the inlet humidity is high, the outlet dew point requirement is mild, and the regeneration energy budget is tight. Choose molecular sieve when the outlet dew point requirement is below minus 40 °C or when the inlet humidity is so low that silica gel capacity falls off the isotherm.

Are the indicator chemistries safe?

Cobalt chloride blue indicator is restricted in some jurisdictions because cobalt is classed as a category 1B carcinogen. Methyl violet orange indicator is the cobalt free alternative and is the preferred chemistry for European, pharmaceutical, and food adjacent service.

What is the regeneration temperature window?

120 to 180 °C for full water release without damage to the gel structure. Below 120 °C the regeneration is incomplete. Above 200 °C the surface area degrades and the working capacity falls. A dryer designed for waste heat regeneration sits comfortably in this window.

What capacity should I expect at low humidity?

Around 8 to 12 percent by weight at 20 percent relative humidity and 25 °C. Capacity ramps steeply through the middle of the isotherm and saturates at 38 to 42 percent above 70 percent relative humidity. Bed sizing should use the inlet humidity not the outlet humidity.

How is the spent or saturated indicating gel regenerated?

Indicator chemistries restore their dry colour on regeneration at 120 to 150 °C. The colour change is reversible across many cycles. End of life is reached when the gel no longer fully returns to the dry colour after regeneration, signalling pore structure damage.

Specify the Right Grade with the SorbiTech Engineering Team

Submit process duty data and receive a written recommendation with grade, sizing, packaging, and lead time.

contact@sorbitech.com