Emerson Exchange 365

Dears,

I have a customer who is measuring PH for a Calcium/Sodium bromide.  the customer keeps facing frequent failures in PH sensors , almost the life time of the sensor ( Rosemount 396P) is less than a month.

below is application details, I would appreciate any recommendations for a different sensor type to suit this application :-

CaBr2 production:

CaO + 2HBr àCaBr2+H2O

R-1521 is a batch reactor.

1. a heel From the previous batch is retained in the reactor R-1521.
2. The reactor is agitated and the contents are heated via steam on the reactor jacket or cooled via cooling water on the pump around cooler E-1521 or through the jacket.
3. Lime (1/3 rd the total amount) is added followed by HBr solution (also 1/3^rd the total amount). This addition sequence is repeated. Reactor temperature maintained is between 80C to                                                             105C The reactor is open to atmosphere. At the end of the reaction the reactor pH is basic (~9 pH) and crude color is milky white.
4. HBr solution is added to drive the pH down to acidic (2-3 pH with 10:1 dilution). The crude color changes from milky to pink to red.
5. Lime is added to drive the pH up to basic (9.2-9.8 pH with 10:1 dilution)
6. While the agitator is running  pump the crude CaBr2 solution to the filter feed tank T-1523.

NaBr production:

NaBr + HBr àNaBr+H2O

R-1521 is a batch reactor.

1. a heel From the previous batch is retained in the reactor R-1521.
2. The reactor is agitated and the contents are heated via steam on the reactor jacket or cooled via cooling water on the pump around cooler E-1521 or via the reactor’s jacket.
3. Initially, HBr solution (~ 50 kg) is added into the reactor. Then the reactor is cofed with both the 55% HBr solution and the 50% caustic solution. The cofeed ratio maintained is (2.2 neat HBr /neat NaOH) or (1.85 =55% HBr /50% NaOH). Reactor temperature maintained is between 80C to 105 C. The reactor is open to atmosphere. At the end of the reaction the reactor pH is basic (~ 9 pH).
4. HBr solution is added to drive the pH down to acidic (2-3 pH with 15:1 dilution).
5. Caustic is added to drive the pH up to basic (9.5-10.5 pH with 15:1 dilution)
6. The reactor product NaBr is pumped into T-1523, then filtered through