For the manufacture of low and medium density detergents.

A Detergent Spray Drying DSD plant is designed for the production of low and medium density detergent powders (250 - 400 g/l). This process is the workhorse of detergent production around the world. 

By it, you can produce laundry washing powders (either for hand-washing and for automatic washing machines) as well as dishwashing powders. The product obtained by DSD Spray Drying plants is a granule in form of hollow bead thus involving the following advantages:

  • low density product and appealing shape (reduced costs per unit of volume)
  • fast and easy dissolution in water (important for hand-washing powders)
  • product appearance very well accepted by most markets in the world.

In the post-addition section it is also possible to increase the product density up to 500-650 g/l.

The first operation in a Detergent Spray Drying plant is the slurry preparation, by which a suspension of powders (Sodium Sulphate, Sodium Tripolyphosphate or Zeolite, etc.) in liquids (LABS Linear Alkyl Benzene Sulphonate, sodium silicate, water, etc.) is prepared using a special vessel (Crutcher). The slurry is discharged into an Ageing Vessel where various reactions are completed and operating also as buffer tank for the subsequent operations.

The slurry is then filtered and then passes through a Homogeneizing Pump, the purpose of which is to eliminate any possible lumps and, at the same time, to create enough pressure to feed the High Pressure Pump. Any metallic materials are blocked by a Magnetic Filter.

A High Pressure Pump generates the necessary pressure for the optimal spraying of slurry with special nozzles placed at the top of the Spray Tower. In this way very uniform droplets of slurry are produced in order to ensure uniform and adequate dimensions of the dried product.

The drying medium is hot air produced with a burner. A fan supplies air to dilute combustion gases at the requested temperature and then this air-gas mixture enters in the Spray Tower. Hot air flows upward, while slurry droplets fall toward the bottom. The contact with hot air generates the evaporation of water inside droplets, which dry and also take the shape of hollow beads. 

The evaporated water leaves the tower from the top, together with exhaust air. A fan draws it out and discharges it into the atmosphere after having filtered it.

Dried detergent powder is discharged at the bottom of the Spray Tower and a Belt Conveyor takes it to the Air Lift section, a sort od pneumatic conveyor that cools and crystallises the detergent and, at the same time, to raises it.

The discharged product falls onto a Vibrating Sieve to separate lumps (recycled in slurry preparation) and then it is finally perfumed, if a Post-Addition section is not included.

At this stage the detergent base can be stored inside one or more Storage Silos or inside buggies, in case of small plants.