14
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Neutralization Unit The sulphonic acid outcoming 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.
The main features of the proposed unit are:
A. Double Step Neutralization Units -
High shear mixers of Desmet Ballestra proprietary design, ensuring intimate mixing of reactants even at high concentration conditions
-
Accurate control of the temperature profile in the loop thanks to the high recycling rate and the low pressure drop cooler so to prevent any risk of product degradation
- Easy in-line transition from low concentration (27-30%) to high concentration (70-75%) paste production -
Accurate control of free alkalinity
B. Vacuum Neutralization Unit -
Efficient Dioxane removal from 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 to prevent any risk of hydrolysis
-
High flexibility: capability to process any kind of raw material/product with possibility to easily switch from one raw material to a different one with minimum product contamination
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SULPHUREX F New Exhaust Gas Treatment
SO 3 Gas
Exhaust Gas to SO 2 Scrubber
Organic Material
FILM SULPHONATION REACTOR
2ND Cyclone
WET FILTER 1ST Cyclone
SULPHONIC ACID TO AGEING / NEUTRALIZATION
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Exhaust Gas Treatment Unit The exhaust gas exiting the sulphonation reactors is processed to reduce the level of pollutant to values widely accepted by the most stringent international standards on emissions to atmosphere. The maximum content of the polluting agents
guaranteed at plant stack are the following: - Organic mist : 25 mg/m2 - SO3 : 15 ppm (vol.) - SO2 : 5 ppm (vol.) The exhaust gas undergoes 2 subsequent steps of treatment before being released to the atmosphere: reduction of organic mist content and
final washing with a caustic soda solution to reduce the amount of free SO2 discharged. This latter step is carried out in a suitable SO2 scrubber, while for the elimination of the organic mist Desmet Ballestra can offer 2 alternative technological solutions having the same efficiency:
Electrostatic Precipitator : The updated design of the Desmet Ballestra ESP includes honeycomb shaped tube bundle for optimized fluodinamic inside the ESP and more compact design and hastelloy electrodes for higher reliability and lower maintenance cost.
N.E.G.T : The new unit is based on a special brink filter constantly washed with fresh organic raw material. This new system, while guaranteeing the same performances (in terms of cleanness of the gas at the stack outlet), allows the complete recovery of the sulphonic acid carried over by the exhaust gas. The cost related to the disposal of the ESP drippings, which constitute a problem of increasing importance for the surfactant manufacturers due to the worldwide concerns on pollution control, is therefore totally eliminated. An additional advantage of the proposed gas treatment system is that it enables the recovery, as finished product, of the organic otherwise normally wasted. This factor constitutes a non-marginal improvement of the whole process economics. Finally the new system is characterized by a minimum maintenance cost.
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Special Plant Configurations The previous pages illustrate the standard Sulphonation Plant configuration as required by the most common applications for the surfactants and detergents industry.
Nevertheless specific plant configurations are necessary/available for the production of few surfactants specialties. Hereinafter the common specific
configurations are briefly illustrated. For each case, more detailed and dedicated documentation is available on demand.
most plant
TYPICAL
DRY METHYLESTER SULPHONATES Plant Configuration
AIR DRYING
ME
SO3 PRODUCTION
SULPHUR MELTING
FILM SULPHONATION
EXHAUST GAS TREAT.
MES AGEING
MES COOLING & RE-ESTERIFICATION
DOUBLE STEP NEUTRALIZATION
MES BLEACHING / AGEING
MES-DRYING
MES FLASH PRECONCENTRATION
MES COOLING / FLAKING
MES MILLING
Standard Units Additional Units
DRY-MES powder
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TYPICAL
DRY ALPHAOLEFINS SULPHONATES Plant Configuration AIR DRYING
AO
SO3 PR ODUC TION
SULPHUR MELTING
FILM SULPHONATION
EXHAUST GAS TREAT.
NEUTRALIZATION
AOS HYDROLYSIS
AOS FLASH PRECONCENTRATION
AOS-DRYING
AOS COOLING / FLAKING
AOS MILLING
DRY-AO S powder
Standard Units Additional Units
DRY LAURYL ALCOHOL SULPHATES
NEUTRAL PASTE
WIPED F I LM E V A P O R A T O R
CONDENSER
CONDENSATE
VENT
FLAKER
EXTRUDER CONDITIONED AIR SLS NEEDLES
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800 People operating in 27 languages Desmet Ballestra S.p.A. Via Piero Portaluppi, 17 20138 - Milano - Italy Tel. : +39 02 50831 Fax. : +39 02 58018449 E-mail :
[email protected] http://www.ballestra.com 2008-04-09
