Direct neutralization of sulphonic acids in a wiped film evaporator for the production of top quality, deaerated and « dioxane-free » ethoxysulphate paste as well as the neutralization of all the other anionic sulfactants.
The sulphonic acid outcoming from the sulphonation unit is neutralized with caustic soda or an alternative alkaline agent (i.e.: Ammonia) in a special Double Step Neutralization Unit or, specifically for Ether Sulphates processing, in a Vacuum Neutralization Unit to yield high active neutral paste (70-75% concentration). In both cases, the neutralization process is carried out at high pH values to guarantee the necessary chemical stability to the reaction mass. Final product pH value is adjusted in-line by addition of a buffering agent in a final mixer.
Major advantages of the Desmet Ballestra Vacuum Neutralization Technology
- Efficient Dioxane removal from the finished product by evaporation of the azeotropic mixture water/dioxane
- Possibility to achieve dioxane content in finished product (SLES) below 10 ppm when coupled with the Desmet Ballestra MTFR
- Product deaeration to increase density and improve appearance (transparency)
- Mild operating conditions with accurate control of temperature profile and minimum residence time of the product at high temperature so as to prevent any risks of hydrolysis
- High flexibility: capability to process any kind of raw material/product, with possibility of easily switching from one raw material to a different one with minimum product contamination