Chlorine Dioxide Analyzer

Inline chlorine dioxide measurements

optek’s chlorine dioxide (ClO₂) analyzers are inline devices designed to measure real time ClO₂ solution strength and/or ClO₂ gas concentration . These analyzers can be designed to accommodate virtually any measuring range regardless of the stream’s phase. Operationally, the analyzer passes a white light beam through the ClO₂ stream to be monitored, where light absorbance is measured at two distinct wavelengths.

Measuring at two wavelengths is better than one

The measuring wavelength is set to focus on or near the peak of the ClO₂ absorbance curve, while the secondary wavelength is chosen to compensate for any influence due to light scattering such as:

• window fouling
• particulate / suspended solids
• immiscible fluids
• gas bubbles

Together, the sensor yields very repeatable and extremely reliable ClO₂ concentration values under process conditions without the use of consumable reagents.

optek inline chlorine dioxide analyzer measuring two points along with the reference channels

Chlorine Dioxide Generator Monitoring

Chlorine dioxide is commonly used as a bleaching & disinfection agent, and is considered the safest and most effective for industrial applications. In facilities where high concentrations or large volumes are required for use as a bleaching agent (i.e. pulp & paper mills), ClO₂ will be manufactured on-site using a ClO₂ generator. In these instances, ClO₂ gas concentration from the generator will be monitored to gauge the relative efficiency of the generating process, while ClO₂ solution strength will be monitored after the absorption tower to know the exact concentration being produced.

In other facilities ClO₂ is used as a disinfection agent. In these instances a volume of relatively higher ClO₂ concentration is made, which is then dosed into a stream to achieve a lower target ClO₂ concentration (drinking water, ballast water, etc.) being monitored by an optek chlorine dioxide analyzer. The ability to monitor the ClO₂ concentrations in real time allows plant operators to achieve peak generator performance, lowest operational costs, and optimum product quality.

What makes optek's chlorine dioxide analyzer systems better?

A complete Optek ClO₂ analyzer utilizes a C4422 converter, an AF26-VB sensor and a titanium or TFMC (Teflon) process connection. Together, this package offers the following advantages:

• Chlorine dioxide measurements without use of consumable reagents
• ClO₂ measurements independent of flow rate or flow velocity
• Can accommodate two independent measurement points on one C4422 transmitter
• According to ATEX: Can be installed in Zone 1 (EPL, "Gb") or in Zone 2 (EPL, "Gc"). Conform to IECEx.
  According to FM: Can be installed in Class 1, Division 1 or Class 1, Division 2 areas
• In the case of ClO₂ gas measurements, can compensate for temperature and pressure swings
• Independent monitoring of the reference wavelength, giving a real-time indication of window fouling
• System comes with a NIST traceable validation filter allowing for an online check of sensor performance
• Utilizes a tungsten filament lamp ensuring long lamp life and consistent emissivity

Realworld examples of measuring chlorine dioxide inline

• Pulp & Paper Mills
  • Chlorine dioxide gas concentration exiting ClO₂ generator
  • Chlorine dioxide solution strength after absorption tower or from storage
  • Chlorine dioxide residual after exhaust scrubber
  • Chlorine dioxide residual at top of absorption tower
• Water Treatment Plants
  • monitor ClO₂ solution strength before and after dosing
• Monitor ClO₂ solution strength for treating ballast water on ships
• Monitor ClO₂ solution strength for medical waste disinfection
• Monitor ClO₂ solution strength for treating produced water prior to re-injection