Chemical Industry

Process control and emissions monitoring in a chemical plant is a challenge due to corrosive gases, high dust load, and high temperatures. To use an extractive system in this environment will demand a lot of maintenance.

The OPSIS DOAS system is different and provides chemical plants with an accurate analyser that will operate with a minimum of maintenance. The OPSIS DOAS system is based on a non-contact method using an optical measurement path that can operate across the duct.

The optical light is transported in an optical fibre to the analyser and one analyser can operate several paths.

As well as monitoring common gases such as nitric oxide (NO), nitrogen dioxide (NO2), sulphur dioxide (SO2), carbon dioxide (CO2) and water vapour (H2O), systems are available to meet the specific needs of particular users:

  • Hydrocarbons (benzene, toluene, xylenes, ethylbenzene, styrene, methylbenzene, methane, etc.) in refineries, petrochemical plants and steel industry.
  • Chlorine (Cl2), carbon disulphide (CS2), ozone (O3), chlorine dioxide (ClO2) in textile industries, pulp and paper mills and colour pigment production.
  • Hg mercury in power plants, waste incinerators, crematorium, etc.
  • Ammonia (NH3) to control DeNOx scrubbers, fertilizer producers, mineral wool, fibre board producers, etc.
  • Phenol in mineral wool plants and fibre board production.
  • Formaldehyde in mineral wool plants and fibre board production.
  • Process (H2S) monitoring in refineries and steel plants.
  • HF in aluminium and alumina plants, waste incinerators, fertilizers, refineries, etc.

HCl in waste incinerators, etc.
In addition, OPSIS offers dilution extractive and heated extractive systems and instruments for oxygen and mercury monitoring.


  • Combines the benefits of UV/FTIR DOAS and TDL technology
  • Best performance according to QAL 1 certification
  • Longest calibration interval according to QAL 1 certification
  • No sampling required, non-contact measurement system
  • Operates with a minimum of maintenance
  • Low energy consumption
  • Gas calibration only once per year
  • Internationally approved
  • Thousands of systems installed worldwide
  • Serviced by highly skilled service network

    System Overview

    UV and FTIR DOAS and TDL monitoring systems for chemical plants

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  • Kemira Chemicals

    Demands from the authorities led the Swedish chemical producer Kemira Chemicals to install their first OPSIS system in 1988. Over the years, they have installed another five monitoring paths for measurement of SO2 and NOx.

    “The system just continues to run…”

    Read the full case here »


  • SO2 Monitoring in Sulfuric Acid Production Plants

  • Fence-line Monitoring

  • Annual Calibration

  • System 400 - One System, Three Solutions

  • System 400 - One System, Three Solutions (Short Version)

  • System 400 - One System, Three Solutions - Fast Loop

  • System 400 - One System, Three Solutions - Cross-stack

  • Benzene Fence-line Monitoring at Refineries

  • OPSIS Data Services

  • System 400 – One System, Three Solutions – HWE

  • Mercury Monitoring