pH is measured to control caustic addition to the stripper to maintain a pH level that balances efficient stripping of hydrogen sulfide with efficient stripping of ammonia. Measuring pH in sour water can be challenging due to the high temperatures and the tendency of hydrogen sulfide to poison and plug a sensor's reference junction. Sensors measuring sour water often have a short life. The Rosemount™ 3500P pH Sensor features high-temperature glass, poison-resistant electrolyte and a double reference junction to provide maximum sensor life in sour water.
The Rosemount 5081 Explosion-Proof Transmitter is a single channel loop powered device that can accept input from a variety of liquid analysis sensors including: pH/ORP sensors, conductivity sensors (contacting and toroidal) and amperometric sensors (dissolved oxygen, chlorine and ozone). The transmitter features a rugged, weatherproof, corrosion-resistant enclosure to withstand harsh environments.