Gas Cleaning › Ammonium Nitrate Granulator Dryer

NITROGEN FERTILISERS / AMMONIUM NITRATE – GRANULATOR DRYER

PROCESS INFORMATION

Ammonium Nitrate (NH₄NO₃) is granulated then dried as a final process stage.

The drying process emits both Ammonium Nitrate dust and Ammonia at appx. 50 °C :
Typical Inlet dust load: 15,000 to 20,000 mg/Nm³ Ammonium Nitrate prills

Typical Inlet Ammonia load : 40-50 mg/Nm³

PROBLEMS TO SOLVE

Air pollution

Product loss (collected AN can be recycled within the plant)

Excessive liquid effluent handling

DESIGN SOLUTIONS

‘BECOFLEX’ BF series Rotating Brush Scrubber in 304L Stainless Steel, irrigated with 25 – 50% AN solution. Various unit sizes are available from 200 to 25,000 Nm³/hr in a single unit, or we can design for larger gas flows in a combination of units in parallel.

Reference installations handle more than 80,000 Nm³/hr flows, and meet the guarantees of <10 mg/Nm³ of AN dust and <5 mg/Nm³ of Ammonia.

The ‘BECOFLEX’ principle of operation is a wetted fibre brush rotating at high speed in a special volute fan casing, thus creating an extremely dynamic gas-liquid contact. This means the unit is self-cleaning, and does not block with solids.

Particles in the dirty exhaust gas stream are drawn into the unit by the suction generated by the rotary brush, and they impact at high speed with the spinning brush fibres and become thoroughly wetted. The next effect is for the particles to be centrifugally washed off, to impact on the wetted inner surface of the volute.

The resulting slurry is then propelled along the bottom of the exit duct to the disengagement vessel, where it falls by gravity to the bottom for removal or recirculation. The cleaned gas meanwhile flows upwards from the duct into the disengagement vessel and towards the top gas exit.

The BECOFLEX system uses relatively small volumes of liquid and acts as its own air mover. This usually means there is no need for a separate fan, but in some cases a secondary or main fan is also used, particularly with long upstream processes.

(See the schematic image below and for more details on BECOFLEX unit sizes, flows etc, see Becoflex under the Products / Gas Cleaning section)

AN Granulator Dryer Installation of BECOFLEX

BECOFLEX BF SCRUBBER SYSTEM SCHEMATIC

• BlueFil® mesh used in a scrubber (vertical – e.g. counter-current, or horizontal – e.g. Cross Flow style), with irrigated stage followed by a demisting stage. (See range of common Bluefil® mesh combinations below)

BlueFil® cross-flow scrubber installation – irrigation stage