Moisture content of soap pellets differs
depending on the desired characteristics of the soap bar.
On-line moisture measurement at the exit of the Spray Dryer/Pelletizer
provides immediate feedback on moisture levels enabling more
rapid optimization of the process upon start-up, on-going
cost savings from more efficient usage of the drier, and consistent
high quality product.
Soap Production Process
Soap results from a saponification reaction between fat, oil
or fatty acids and inorganic water-soluble bases. The fats
are commonly beef or mutton tallow, coconut or palm kernel.
After pretreatment of the fats/oils to eliminate impurities
and impart color or odor, saponification by continuous or
batch process results in liquid soap, also known as neat soap,
and the by-product glycerine. The latter is removed and refined,
and the liquid soap enters a vacuum spray drier which dries
the soap prior to it entering a pelletizer.
The pellets are stored in pellet bins before undergoing their
final conversion into bar soap.
Moisture measurement is made at the exit of the pelletizer,
the 4-20 mA output can be used to control steam pressure in
the heat Exchanger which influences the moisture content of
the pellets. The gauge is installed at an angle of 20º to
the horizontal in order to minimize specular reflection. If
the exit chute is enclosed, the product can be viewed through
either a viewing window or an insertion probe.