The process control of a CO2 capture plant needs good and reliable detection of gas phase NH3, and CO2. Measuring NH3 is a challenge due to the corrosive environment and high concentrations of NH3. Several places in the process needs to be monitored and to transport the sample is difficult. A large dynamic range is needed as the NH3 concentration can vary between 15% volume and a few mg/m3. To use an extractive system in this environment will demand a lot of maintenance.
The OPSIS DOAS system is different and provides CO2 capture 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. Besides the measurements of NH3, CO2 can be measured with the same analyser. Additionally, several other gases can be measured with the DOAS system.