ORP sensor

J

Thread Starter

Joy

Can anybody tell me if ORP analysers can be used for chlorine analysing in RO plant process? We are having 2ppm Sodium Hypochlorite dosing in the inlet of the RO plant and sodium meta sulphate dosing to remove excessive chlorine. Chlorine analyser (ORP) is installed after the sodium meta sulphate dosing to check any chlorine residue is there.

Thanks
 
F

Francois Caron

ORP sensors can be used to determine if free chlorine is present. You will need to prepare free chlorine calibration standards using the Sodium Hypochlorite but make sure it as the same pH as the sample flow (ORP will also flunctuate based pH). Let's assume your high free Cl2 alarm setpoint is 0.1 ppm, prepare cal. standard and use it to get the equivalent XmV value. This will be your high alarm setpoint.
 
B

Bob Peterson

I have seen this exact thing done, however, there is no way I know of to calculate what the ORP setpoint should be for a desired Cl level. You have to find this out emperically for you specific situation, but once you find what this setpoint is, it does work fairly well as a means of controlling Cl level.
 
Sensorex also makes a calibration kit, part number B125. This kit uses pH buffer and Quinhydrone to make known solutions of 90 and 260 mV. You then have a reference point to refer your chlorine solutions to. Web site is http://www.sensorex.com

Mike Ross
 
It will work.

In our plant we are concerned about chlorine level to the RO membrane. If chlorine enter in to the RO membrane will damage the membrane.

We are proved ORP sensor will suitable for this process. We have set alarm level at 300 mV, because 350mV chlorine traces are found inlet of the membrane.

Anybody want details please contact me in my following ID.

Thanks for all help.

Joy
[email protected]
 
Top