En construction
A key product of the chemical industry, caustic soda is commonly produced by
electrolysis of brine solution through membrane cells. The resulting low
concentration of caustic soda (32% NaOH) can be concentrated up to 50%, 73% or
even to solidification (99.5% NaOH or higher) and then be used in a wide range
of applications, such as pulp and paper, cellulose based textile, alumina,
soap, detergent, cleaners and many others.
Our know-how acquired over
almost a hundred years in the chlor-alkali industry, starting with the
diaphragm and mercerising caustic soda field, our wide experience in many
process industries and our expertise in heat transfer, allow us to provide an
optimised design of caustic soda concentration units.
Compact and
modular, caustic soda units are well suited to the skid mounted conception :
easy to transport, they require little manpower to set up and run on.
Facing highly corrosive properties, it is important to choose the right
material, suitable for a long life and safe plant operation. Factors enhancing
corrosion risk such as high temperature, mechanical stress and specific
impurities must be taken into account when designing the unit. Kestner has
successful experience with different materials such as Nickel 200 and 201,
Incolloy 825, stainless steel 316 L and 304L, etc …. Low metal content in the
concentrated caustic soda is therefore guaranteed.
Anhydrous
concentration of caustic soda is among Kestner‘s strengths. From 32% or 50%
NaOH, with a possible 73% NaOH intermediate step, we are able to concentrate
the caustic soda up to 99-99.5% with climbing and falling film evaporators. The
resulting high quality of the product allows the production of flakes,
pastilles and prills. The recommended process ensures a smaller boiler size and
minimum energy consumption.
Reaching temperature higher than 350°C,
anhydrous caustic soda is not easy to treat : Kestner is used to dealing with
complicated parameters such as material choice, good control of heating media
and transfer of very high freezing point solutions.
Kestner is also
well known to provide calcium chloride concentration and crystallisation units.