Opsis AB

Continuous emissions monitoring for aluminium smelters

Process control and emissions monitoring in an aluminium smelter is a challenge due to the high concentrations of HF. To use an extractive system in this environment will demand a lot of maintenance.

The OPSIS DOAS system is different and provides aluminium smelters 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. A single OPSIS system will measure all relevant gas components such as HF, NOx, SO2, CO, CO2, and others.

OPSIS has three specific application possiblities in smelters.

  1. Open-path monitoring in large indoor work areas, the potrooms.
  2. In situ monitoring across a stack or duct.
  3. Ambient air quality monitoring outside the plant.


  • Automatic optical alignment
  • Multi-gas and multi-path system
  • 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