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 surfactants.
The sulphonic acid outcoming from the sulphonation unit is neutralized with caustic soda or an alternative alkaline agent (i.e.: Ammonia). The reaction can be accomplished 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) with low residual dioxane. 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 the 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: the system is capable to process any kind of raw material/product, with the possibility of easily switching from one raw material to a different one with minimum product contamination
In addition to the technology described above, Desmet Ballestra can propose the proprietary
Ultra-Low Dioxane Ethoxysulphates Production Technology
aimed to produce 70% concentration SLES paste with a residual content < 5 ppm of 1,4-Dioxane on 100% Active Matter basis, responding to the new US environmental restrictions (NY State bill - S4389B)
Main features of the new system:
- Contemporaneous neutralization, de-aeration & 1,4-dioxane stripping
- No risk of quality degradation thanks to the mild operating conditions
- Direct production of 70% concentration product
- Dioxane removal up to 90%
- Lower energy consumption: approx. –50% compared to a conventional stripping system
Please click the video below to see the presentation of Emanuele Caimi, Sales Director Detergents&Surfactants, at the ICIS Digital Surfactant Conference – Sept 16-18, 2020.
Minimizing 1,4 – dioxane content in ethoxysulphates: technology and future trends