Technical Grade Ammonium Nitrate

Thanks to its in house technology for the production of Technical Grade Ammonium Nitrate (TGAN), CEAMAG can deliver engineering services starting from preliminary feasibility study up to lump sum turn key contracts.

CEAMAG masters the TGAN technology thanks to its team of highly skilled engineers having been involved in design and commissioning of most of the new and revamped TGAN plants in the last decade.

 

Highlight of Proposed Technology

Quality of Product

Thanks to its micro porosity, TGAN manufactured with CEAMAG technology is considered as premium quality TGAN. Fuel oil is dispersed by capillarity throughout the particles ensuring a uniform and rapid fuelling of product without any release of fuel even after a long storage of the ANFO. Roundness and uniform size of the product make it free flowing.

Adjunction of a crystal habit modifier allows obtaining particles made of “stacking” of almost cubic crystals rather than “needle shape” crystals that are usually produced during crystallization of ammonium nitrate. These cubic crystals are less sensitive to dilatation/contraction that occurs during phase transition. Internal structure combined with its low moisture content make the TGAN manufactured with CEAMAG technology suitable for use in tropical area where thermal cycling is likely to happen.

 

Operation of the plant

In opposition to other technology where a slight variation of operating condition (pH, strength of AN solution…) can have dramatic consequence on the quality of end product, the technology proposed by CEAMAG “forgives” many more transitory operating conditions.

Dust formation in TGAN plant is usually a major concern, but due to the very good mechanical property of TGAN ; almost no dust is formed in plant using CEAMAG’s technology, making the use of dedusting device useless. Similarly the quantity of off spec product that needs to be reprocessed is negligible.

 

Process Description

Prilling

Ammonium Nitrate melt coming from the synthesis section (CEAMAG can deliver technology for this section as well) is sprayed in a prilling tower. Droplets of Ammonium nitrate melt falls in counter current to a cold stream of air and are partially crystallised.

The hot air that leaves the prilling tower is scrubbed and is either sent to atmosphere or recycled back to the process according to environmental policy of the customer.

Technical Grade Ammonium Nitrate process - Prilling Tower

Prilling Tower

 

Drying and screening of the product

At the bottom of the prilling tower, the AN prills are sent to the dryer drum. In the Dryer, the product is dried by hot air, flowing in the first part in co-current and in the second part in counter-current with the product. Controlled evaporation of water in the dryer combined with crystallisation of saturated Ammonium Nitrate solution allows creating an evenly distributed porosity within the particles.

From the outlet of the Dryer B301, the product is conveyed to the screen S301 where undersized and oversized particles are separated from the final product.

Undersized and oversized prills are recycled to the AN Solution Tank where they are dissolved and returned to the Prilling section.

Process air used in the dryer is scrubbed before being exhausted to the atmosphere.

Technical Grade Ammonium Nitrate process - Inside of a dryer

Inside of a dryer

 

Cooling and coating

On-size product coming from the screen is sent to the Fluidized Bed Cooler to be cooled below the IV-III transition point, it is subsequently coated with an anti caking agent to avoid that end product picks up moisture in the storage.

 

 

Product Specification

Main figures
AN content: More than 99.7%
Oil absorption: More than 7% (adjustable up to 12%)
Oil retention: 6% - 3 month from date of fueling
Density: 0.72 to 0.78
Moisture content: Less than 0.12% w/w
Mean size: 1.6 -1.8mm
Low friability  
Free flowing  

 

Typical Utilities Consumption

Consumption varies from one plant to another according to atmospheric conditions and local regulation for emission. However typical consumption figures of CEAMAG technology can be as follows:

Typical figures
LP Steam: 120 kg/ton TGAN
Cooling Water: 15 m3/ton TGAN (@ dT=5°C)
Electricity: 45 kW/ton TGAN

 

 

Effluents

Effluents
Liquid effluent: nil
Dust in gaseous effluent: 30 ppm
Ammonia in gaseous effluent: 20ppm