The bromine recovery plant is designed as a continuous duty plant. Please refer the attached drawing. The NaBr feed may be required to be pre-treated if it has the ingress of the organic and other impurities. The pre-treated NaBr solution from the tank (T-1) is fed to the plant by pump(P-1). The feed is split so that approx. 20% of the fed solution is used to scrubunreacted chlorine in the packed column (C-3). The remaining feed ispreheated in the heat exchanger (E-1) using effluent from the reaction column.The two streams are then mixed and fed to the reaction column. Vaporizedchlorine and steam are also fed to the reaction column.In the reaction stripping column (C-1) the solution is contacted with chlorinewhich displaces the bromine in producing free bromine. This liberated bromineis stripped out of the solution by live steam.
The bromine and water vapour stream leaves the top of the column and entersthe condenser (E-2). Condensate falls into the Separator where it forms twophases, the light aqueous phase being returned to the column (C-1), while theheavy bromine phase feeds the purification column (C-2).Purification of the bromine is achieved by distillation. Heat is being introducedby the re-boiler (E-4). Bromine and water vapour leaves the top of the columnand enter the Condenser (E-6). The condensate falls as reflux to thepurification column (C-2). All dissolved gases in the crude bromine are releasedin the purification column.Pure bromine overflows from the base of the column via a product cooler (E-5)to product receivers or buffer storage vessels.E-7 is the vent condenser connected to the vent lines of the system.The system vent is connected to the packed column (C-4) and Ventury.
Scrubber (VS-1) operating on dilute alkali as the motive fluid. Any unreactedchlorine / bromine vapour is thoroughly scrubbed in the packed column andVentury Scrubber prior to discharge to the atmosphere. The ventury creates asmall negative pressure (draft) in the system and keep all the vent lines cleanand dry.
The process operates by regulating the flow rates of bromide feed, chlorine andsteam into the reaction column.