YouthfulEngineer
Chemical
- Sep 24, 2007
- 3
I am investigating a control system for pH control for an ammonia stripping column.
The ammoniacal liquor contains both ammonia (NH3) and ammonium ions (NH4+). Caustic (NaOH) is added to liberate ammonia as product which is distilled off.
The pH of the remaining effluent however needs to be steady between 9.5 and 10.5 pH. The current system which uses a centrifugal pump and control valve system gives quite a highly fluctuating pH value. The control valve is controled via the pH sensor readings.
My question is whether the control of effluent pH would be improved if the ammonium ion concentration of the feed was monitored to provide the set point for the amount of caustic sent to the column. In effect providing a feed forward control rather than the current pH monitoring (feed back control)
sorry for the long winded background.
The ammoniacal liquor contains both ammonia (NH3) and ammonium ions (NH4+). Caustic (NaOH) is added to liberate ammonia as product which is distilled off.
The pH of the remaining effluent however needs to be steady between 9.5 and 10.5 pH. The current system which uses a centrifugal pump and control valve system gives quite a highly fluctuating pH value. The control valve is controled via the pH sensor readings.
My question is whether the control of effluent pH would be improved if the ammonium ion concentration of the feed was monitored to provide the set point for the amount of caustic sent to the column. In effect providing a feed forward control rather than the current pH monitoring (feed back control)
sorry for the long winded background.