Liquid Analyzers for Electrolysis Plants

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Process liquid analyzers such as pH meters, conductivity meters, ORP meters, and density meters play an important role at electrolysis plants in the control of concentrations of various process solutions. This requires both precision and stability under harsh conditions that include highly corrosive substances, high temperatures, and many impurities.

Expected Benefits

  • Ensures stable, continuous measurement in heavily contaminated liquids
  • Reduces operating costs
  • Eliminates the need for manual cleaning

List of Analyzers

Type Measurement point Objective
pH meter 1) Supersaturated brine at raw salt dissolver outlet *1 pH control for impurity removal in brine Control value: 10.8 to 11.0 pH
2) Refined brine *2 Control of precipitation of impurities Acid range
3) Brine at electrolysis tank inlet *3 pH control of electrolysis tank brine inflow: 3 to 6 pH
4) Return brine at electrolysis tank outlet *4 Efficiency control in dechlorination tank Acid range
5) Desalinated water at dechlorination tank outlet *5 Desalinated water control
6) Hydrochloric acid plant drainage *6 Drainage control
Conductivity meter 1) Supersaturated brine at electrolysis tank outlet *7 Brine concentration control: concentration: 300 to 320 g/l
2) Refined brine *8 Refined brine concentration control
3) Sulfuric acid concentration used for drying in chlorine gas drying line *9 Concentration control of recovered sulfuric acid: approximately 74 %
4) Hydrochloric acid concentration in hydrochloric acid plant *10 Hydrochloric acid concentration control: approximately 35 wt%
5) Sodium hypochlorite concentration in a soda hypochlorite plant *11 Sodium hypochlorite concentration control:
Available chlorine: 10 to 15 %
Residual caustic soda: 0.1 to 1% (approximately 10 g/l)
Oxidation reduction Potential (ORP) meter 1) Desalinated water at dechlorination tank outlet *12 Confirmation of dechlorination reaction
2) Soda hypochlorite plant adsorption tank outlet *13 End control of caustic soda chlorination reaction
Vibration type liquid density meter 1) Anode solution at electrolysis tank outlet *14 Anode solution caustic soda concentration control
2) Caustic soda concentration at concentrate drum outlet *15 Product caustic soda concentration control

Solution Details

Solution Details sm

Solution Details


Yokogawa process solution analyzers deliver stable, long-term measurements under the harsh conditions present in electrolysis plants. The ISC202 Inductive Conductivity Meter is specially designed to detect the concentrations of hydrochloric acid, sulfuric acid, and caustic soda. The DPA405 pH Electrode for Chemical Processes can measure pH in a wide variety of processes.

Field Data

Each graph shows a correlation between concentration and conductivity at measurement points, the numbers of which correspond to the ones in the previous page. The ISC inductive conductivity meter's range can be specified, thereby allowing high-resolution measurements in the target concentration range.

Measurement point: *7
NaCl concentration - Conductivity (60 °C)
Measurement point: *7 

Measurement point: *11, *13
NaOCl Plant
Residual NaOH Concentration and Conductivity - ORP
Measurement point: *11, *13 

Measurement point: *11
NaOCl Plant Conductivity when Cl2 is adsorbed in NaOH
Measurement point: *11 

The correlation between concentration and conductivity is largely affected by solution temperature. The ISC inductive conductivity meter provides automatic temperature compensation using the build-in temperature sensor.

Measurement point: *10
HCl Concentration - Conductivity
Measurement point: *10 

Measurement point: *9
H2SO4 Concentration - Conductivity
Measurement point: *9 




EXA DO402G溶解氧分析仪转换器具有灵活、可靠且维护量小的优点。

All-in-One Digital Smart pH/ORP Sensor FU20F

All-In-One pH and ORP digital SMART sensor that keeps the motto "Simple is best" while combing the sensor with built-in intelligence and direct digital communication. 

Flow/NPT Fittings FF20/FS20

Yokogawa has invested considerable design and development time in producing a full range of fittings with particular emphasis on designs that reduce installation and maintenance time and consequently save operation costs.



FU20/FU24/PH20一体化pH/ORP (REDOX)传感器


Hot-Tap Holder PR10

On-line measurements often present extra challenges, especially when routine maintenance is required. The PR10 is ideally suitable for applications where the sensors must be removed without interrupting or shutting down the process. Without any special tools the PR10 can be retracted safely from the process at pressures up to 5 bar (72 psi). Using the PR10 allows us to place any dissolved oxygen sensor that has a PG13.5 connenction into a retractable assembly.

InfraSpec NR800



ISC40型传感器与EXA ISC分析仪组合使用。在可靠性、准确性、可调性和性价比方面,该组合满足甚至优于对电导率测量的期望。 








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