Chlorine gas is used in water treatment and thermal mass flow meters are ideal to measure real-time flow rates of chlorine which is required for optimum water purification.
Chlorine Gas Water Treatment
Chlorine gas is primarily used as a disinfectant for treating water supplies around the world. The main applications are the treatment of drinking water and industrial and municipal wastewater treatment before discharge. Other usages include disinfectant and algaecide in food processing systems, and water cooling systems. Pulp and Paper mills will use chlorine gas as a bleaching agent to remove the undesired color of the pulp stock.
Proper real-time control of the concentration of chlorine is critical for the effectiveness and safety of the operation. Thermal mass flow meters are an important component of this control system to accurately measure the real-time chlorine gas flow rate to obtain optimum water purification.
Accurate flow measurement of chlorine gas creates some challenges which Sage Metering has met with both insertion probes and in-line flow bodies for chlorine gas flow application.
Chlorine Gas Corrosion
While dry chlorine gas is not corrosive, the presence of moisture will create a very corrosive condition. To deal with this potentially corrosive situation Sage Metering can build the probe and sensors with all wetted parts made from Hastelloy. Sage has also built a number of in-line flow bodies made from PVC to provide the necessary corrosion protection.
Chlorine Gas Meter Calibration Challenges
Another challenge is the calibration. As explained in Sage Thermal Mass Flow Meter Calibration, proper calibration of the flow meter is critical and must be performed on a test stand using the actual gas which the unit will be operating on. Due to safety considerations, an actual gas calibration on chlorine is not feasible. In these situations, Sage Metering calibrates the thermal mass flow meter using a surrogate gas and makes adjustments based on theoretical modeling based on the thermal properties of chlorine gas and the surrogate gas.