pH Control in Propylene Oxide Production

The presence of chlorine, a large amount of different (chlorinated) hydrocarbons and precipitating salts make in-line pH measurement very problematic. Therefore, accurate pH control is vital to the process and to secure profitability.

Therefore, most plants running the chlorohydrin propylene oxide process equip their critical control loops with three or four redundant pH measurements. However, the majority of pH sensors have severe difficulties with the process environment and require frequent cleaning and recalibration, placing significant burden on the maintenance department.