Gas-Phase Measurement in Chlorine Production
Monitoring Chlorine, Moisture, Hydrogen, Oxygen, and Nitrogen
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Chlorine production facilities rely on accurate, continuous gas-phase measurement to maintain safe operation, consistent product quality, and reliable process performance. Monitoring critical gas components throughout the chlor-alkali process provides real-time insight into cell operation, gas purity, and abnormal conditions such as air ingress or membrane degradation.
This application note describes what gases are measured, why they are measured, and where measurements are typically installed in chlorine production units.
Key Gas Measurements in Chlorine Production
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Chlorine (Clâ‚‚) Measurement
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Why Measure Chlorine Gas?
Chlorine concentration measurement is used to verify production rate, confirm gas purity, and detect abnormal operating conditions. Accurate chlorine gas measurement supports safe handling and control of downstream chlorine drying, compression, and liquefaction systems.
Typical Chlorine Measurement Locations
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Electrolyzer (cell) outlet
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Dry chlorine header
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Chlorine compressor suction and discharge
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Chlorine liquefaction feed
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Moisture (Hâ‚‚O) Measurement in Chlorine Gas
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Why Measure Moisture in Chlorine?
Moisture in chlorine gas significantly increases corrosion risk and can lead to premature failure of compressors, piping, and storage systems. Continuous moisture measurement verifies chlorine dryer performance and ensures chlorine meets dryness specifications before compression or liquefaction.
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Typical Moisture Measurement Locations
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Chlorine dryer outlet
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Chlorine compressor suction
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Finished chlorine product header
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Hydrogen (Hâ‚‚) Measurement
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Why Measure Hydrogen Gas?
Hydrogen monitoring is critical for explosion prevention and safe plant operation. Measuring hydrogen concentration also confirms hydrogen product purity and provides early indication of membrane leaks or abnormal electrolyzer performance.
Typical Hydrogen Measurement Locations
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Hydrogen cell outlet
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Hydrogen header
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Downstream of hydrogen drying or purification systems
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Oxygen (Oâ‚‚) Measurement
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Why Measure Oxygen in Chlorine and Hydrogen?
Oxygen presence in chlorine or hydrogen streams is typically associated with air ingress or degradation of electrolyzer components. Elevated oxygen levels reduce chlorine liquefaction efficiency and increase safety risk, making oxygen measurement an important indicator of process integrity.
Typical Oxygen Measurement Locations
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Electrolyzer outlet
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Dry chlorine header
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Liquefaction feed
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Nitrogen (Nâ‚‚) Measurement
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Why Measure Nitrogen Gas?
Nitrogen measurement is used to identify air ingress into chlorine and hydrogen systems. Non-condensable gases such as nitrogen reduce liquefaction efficiency and may indicate leaks in piping, compressors, or seals.
Typical Nitrogen Measurement Locations
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Chlorine header
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Compressor suction
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Liquefaction non-condensable vent
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Nitrogen Trichloride (NCL3) Measurement
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Why Measure Nitrogen Trichloride Gas?
Nitrogen trichloride is highly toxic and explosive, and its formation can be influenced by additives in the brine, such as calcium ferrocyanide. Continuous monitoring of the chlorine gas stream ensures safe operation, supports effective NCl₃ scrubbing, and prevents impurity accumulation that could compromise liquefaction or downstream processes.
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Typical Monitoring Locations
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Chlorine cell outlet
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Dry chlorine header
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Chlorine compressor inlet and discharge
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Liquefaction feed
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Scrubber outlet / decomposer inlet
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Benefits of Continuous Gas Monitoring in Chlorine Production
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Continuous measurement of chlorine, moisture, hydrogen, oxygen, and nitrogen provides the following operational benefits:
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Improved chlorine plant safety through early detection of hazardous conditions
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Enhanced reliability of chlor-alkali operations
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Consistent chlorine gas quality and dryness
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Reduced corrosion-related maintenance and unplanned downtime
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Early identification of air ingress and membrane performance issues
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Gas-phase measurement plays a critical role in modern chlorine production and chlor-alkali operations. By continuously monitoring chlorine, moisture, hydrogen, oxygen, and nitrogen at key process points, operators can maintain safe operation, protect equipment, and ensure consistent chlorine product quality.
For more questions or to discuss gas-phase measurement solutions for chlorine production, reach out to a team member at Kaizen Controls and Automation today.
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