producer of soap plants


Dryer for bar soap drying plants

Soap from saponification (Neat Soap) is liquid and hot. The percentage of water contained in it is about 32% and its temperature is about 90°C.
In the final stage of processing, toilet soap has a water content of around 13% and a temperature of 35-40°C. In laundry soap, on the other hand, the percentage of water is higher, around 20-25%, so in order to maintain the degree of plasticity it must be processed at lower temperatures, around 20°C.
The dryer is a machine that allows the right parameters, both in terms of water percentage and temperature, to be reached in a single process, thanks to vacuum evaporation.
The physical mechanism behind the drying system is simple: the hot, moist Neat Soap is introduced into a lower pressure environment. To achieve equilibrium, the excess water evaporates.
In detail, the process proceeds as follows: the liquid soap (Neat Soap) coming from the saponification is sent to the atomiser through a shell and tube heat exchanger. The purpose of this machine is to regulate (increase) the temperature of the soap and also to pre-evaporate a certain quantity of water if the mass balance requires it.
The conditions inside the atomiser are such that the soap releases excess moisture and reaches the desired temperature.
Neat Soap enters the atomiser through a tangential inlet, which limits the formation of dust and facilitates its separation. A rotary scraper cleans the wall of the atomiser, thus preventing soap build-up.
The ready soap, which is dry and cold, falls onto the worms of the plodder to be extruded into the atmosphere (i.e. outside the plant).
The vapours released during the process are sucked out of the vacuum system through powder separators (cyclones). The separated powder is recycled from the second separator into the first one and then from the first separator into the atomiser via powder draws.
In the production of laundry soap, due to the reduced degree of drying, the use of the heat exchanger can be avoided. Furthermore, due to the small amount of vapour separated, it is possible to use a single separator (mono-cyclone).
The vacuum system must ensure that evaporated moisture is removed and residual pressure is maintained at the desired levels. To do this, Soaptec has developed a direct condensation system in the separate circuit that offers many advantages over alternative systems.
The direct contact condenser receives vapours from the system and condenses them with a quantity of cold water sprayed through a group of nozzles located at the top of the appliance.
This water (with the newly formed condensate) undergoes a temperature rise due to the absorption of the condensation heat of the vapours coming from the system. The water is recirculated around the condenser through a heat exchanger in which it gives up this excess heat to the cold water produced by a chiller, which circulates in a counter-corrent flow.
This system offers almost total control of the condensing temperature, ensuring the required residual pressure levels.
Excess recirculating water (the condensate) is eliminated by means of a level maintenance system in the condenser.
By separating the two circuits (polluted water from the plant/clean water from the chiller) any environmental pollution is avoided. The eliminated condensate is recovered in the saponification process.
Any non-condensables, such as air infiltration, are eliminated by the vacuum pump.
On request we can also supply conventional vacuum units with steam ejectors and cooling towers.