Measuring Trace Moisture in an Electrolysis Plant


Electrolysis plants create hydrogen and chlorine from a brine solution. Chlorine gas generated from the anolyte of the electrolysis tank generally contains between 0.5 to 2.0 vol% H2O. The sample is then cooled and filtered to remove brine, subsequently coming out as wet chlorine gas. The wet gas is sent to a drying tower where it is treated with sulfuric acid to get moisture down to the ppm level. Acid mist remains in the dry chlorine gas and is sent to a dry chloride tower to remove the mist. The dry chlorine gas is then sent to a reciprocating compressor for liquefaction. 

The presence of moisture after the dry chloride tower, even at trace levels, causes corrosion of the chlorine compressor and contaminates the product with chlorine hydrate and hydrous iron chloride. Trace moisture levels are conventionally monitored before and after the compressor using phosphorous pentoxide (P2O5) sensors. The P2O5 sensors have slow response times, high maintenance costs (both time and money), and eventually deteriorate due to process contact.


Electrolysis Plant Overview

Expected Benefits

  • Quick identification of process upset and consequently corrective action
  • Avoiding equipment damage and/or product contamination
  • Highly sensitive measurements in the minimum range of 0-30ppm H2O
  • In-situ online validation and calibration minimizes downtime

Field Data

TDLS200 versus P2O5 Sensor

Product Recommendations


TDLS200 Electrolysis Application Picture

  • For additional information please contact Analytical Product Marketing


Related Products & Solutions

In-Situ Gas Analyzer TDLS200

The TDLS200 is designed to make fast, accurate measurements of gases including oxygen (O2), carbon monoxide (CO), methane (CH4), moisture (H2O), carbon dioxide (CO2), ammonia (NH3), and hydrogen chloride (HCl). It is ideally suited for environments involving changing pressure or temperature.

Tunable Diode Laser Spectrometers

Tunable Diode Laser Spectrometer (TDLS) is a laser-based gas analyzer with fast-update optical analysis.


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