Caustic Brine Recovery in Sugar Refinery
PORESEP membrane solution
The Ion Exchange resin gets saturated after some usage and has to be regenerated. It is regenerated chemically using Caustic Brine solution at 12-13 pH. The PORESEP Membrane for Brine recovery recovers 80-90% Caustic Brine without pH correction and temperatures of 60-70 Deg C
Raw sugar with a high ICUMSA value has to be decolorized. There are also two standard methods of colour removal in refineries, both relying on absorption techniques with the liquor being pumped through columns of the medium. One option open to the refiner is to use granular activated carbon [GAC], which removes most colour but little else. The carbon is regenerated in a hot kiln where the colour is burnt off from the carbon. This is a costly process in terms of the energy required.
The more recent option is to use an ion-exchange resin which removes less colour than GAC, but it also helps remove the inorganic contaminants. The Resin process uses the degree of charge on the colours to separate these from sugars by absorption.
The Ion Exchange resin gets saturated after some usage and has to be regenerated. It is regenerated chemically using Caustic Brine solution at 12-13 pH. The cleaning is very efficient, but this gives rise to large quantities of coloured liquid effluents. This was a deterrent to the industry, and various technologies are being employed to re-cycle this effluent water.
The RO process for Brine recovery was efficient but could only get 40-50% brine recovery, and due to the neutralising process, all caustic was lost.The process comprises a series of pre-treatments followed by the Modified Membrine process, where the colours are removed from the effluents at high temperature
Features and Benefits
Poresep Membrine process to recover the Caustic Brine uses modified membranes to carry out the separation under most taxing environments.
- Brine recovery is done without neutralising, as done in conventional systems
- Minimal make‐up of caustic and salt will be there as no acid is required for neutralising the waste stream
- High flux and high-temperature stability at high pH up to 13
- The membrine process recovers up to 75-80% of Caustic brine back into the system.
- Colour concentrate can be further recovered as an option, making caustic brine recovery as high as 90‐95%
- Low effluent loading as most of the colours will be precipitated out in this new process