PcProChem

Process

The Spray Drying Process

Counter-current spray-drying converts atomized slurry into free-flowing base powder in a single pass.

Six stages from slurry to silo

Complete guide to detergent powder manufacturing — from slurry preparation to final powder handling

  1. 01

    Raw Material Dosing

    Weighing & metering systems precisely measure surfactants, builders, fillers, and additives.

  2. 02

    Slurry Preparation

    High-shear mixing tanks combine solids with viscous liquid binders to form homogeneous slurry.

  3. 03

    Atomization

    High-pressure spraying via swirl jet nozzles at 40–50 bar atomizes slurry into fine droplets.

  4. 04

    Spray Drying

    Counter-current hot air stream drives evaporation & agglomeration inside the drying tower.

  5. 05

    Separation & Collection

    Cyclone separators and wet/dry dedusting systems recover powder from the exhaust air stream.

  6. 06

    Post-Blending & Storage

    Cooling, enzyme additive dosing, perfume blending, and silo storage for final packaging.

Tower diagram & design parameters

Counter-current spray drying tower diagram
Tower diameter
5 m · 7 m · 9 m (standard)
Production capacity
≈ 15 / 30 / 50 tph base powder
Disengaged height
≥ 3 m
Drying height
≥ 5 m
Plenum ring angle
20°
Hip section
0.44 D · angle 60–70°
Superficial tower velocity
0.5–1 m/s
Atomization pressure
40–50 bar
Nozzle swirl angle
55–70°
Tower superficial air velocity (NTP)
≈ 10 m/s

Operation sequences

Start up

  1. 01Close all dampers.
  2. 02Start exhaust fans.
  3. 03Open wet cyclone water supply.
  4. 04Start base conveyor.
  5. 05Start air inlet fan.
  6. 06Open fuel valve and ignite the burning furnace.
  7. 07Open spray jets gradually.
  8. 08Raise inlet temperature in steps to set point.

Steady state

  1. 01Inlet temperature controlled by fuel flow rate.
  2. 02Underpressure controlled by exhaust fan speed or damper position.
  3. 03Powder moisture controlled by adjusting air inlet flow rate.
  4. 04Bulk density controlled by slurry de-aeration / re-aeration.
  5. 05Continuously monitor inlet/outlet temperature, ΔP across cyclones, slurry feed pressure.

Shut down

  1. 01Divert slurry away from nozzles.
  2. 02Shut off fuel to the burning furnace.
  3. 03Shut off air inlet fan.
  4. 04Shut off air outlet fan when tower temperature drops below 50°C.
  5. 05Stop conveyors and isolate.

Process control loops

ParameterControlled byTarget
Inlet temperatureFuel flow rate to the burning furnaceSet point ± 5 °C
UnderpressureExhaust fan speed or damper position-20 to -50 Pa
Powder moistureAir inlet flow rate8 – 12 %
Bulk densitySlurry de-aeration / re-aerationRecipe target ± 30 g/L

Plant process sections

Raw material dosing

  • · Powder conveyors
  • · Liquid valves
  • · Weighing systems

Slurry preparation

  • · Mixer
  • · Slurry tank
  • · Pumps
  • · VFD drives

Spray drying tower

  • · Burner
  • · Combustion fan
  • · Inlet / exhaust fans
  • · Temperature & pressure control

Post-blending

  • · Powder mixing
  • · Additive dosing

Liquid storage

  • · Tank farm
  • · Feed pumps

ESD safety system

  • · Emergency shutdown with temperature and pressure switches