Bromine Recovery from NaBr/KBr Solution

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 is preheated in the heat exchanger (E-1) using effluent from the reaction column. The two streams are then mixed and fed to the reaction column. Vaporized chlorine and steam are also fed to the reaction column. In the reaction stripping column (C-1) the solution is contacted with chlorine which displaces the bromine in producing free bromine. This liberated bromine is stripped out of the solution by live steam.

The bromine and water vapour stream leaves the top of the column and enters the condenser (E-2). Condensate falls into the Separator where it forms two phases, the light aqueous phase being returned to the column (C-1), while the heavy bromine phase feeds the purification column (C-2). Purification of the bromine is achieved by distillation. Heat is being introduced by the re-boiler (E-4). Bromine and water vapour leaves the top of the column and enter the Condenser (E-6). The condensate falls as reflux to the purification column (C-2). All dissolved gases in the crude bromine are released in 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 unreacted chlorine / bromine vapour is thoroughly scrubbed in the packed column and ventury Scrubber prior to discharge to the atmosphere. The ventury creates a small 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 and steam into the reaction column.