New Opportunities in Process and Emission Monitoring

At PEFTEC 2015, Dr Peter Geiser, on behalf of NEO Monitors, will be presenting "New opportunities in process and emission monitoring". This talk will take place Thursday 19th November, 2.30-3pm, Room 2. 

Since the negative effect of pollutant gases, in particular nitrogen oxides (NOx) and sulphur dioxide (SO2), on the environment has become evident, governmental agencies like the United States Environmental Protection Agency (US EPA) or the Bundesumweltamt in Germany are adjusting emission directives to lower levels on a regular basis. Suppliers of measurement instrumentation are challenged to enhance the sensitivity of sensors at the same time.

The majority of industrial users has accepted near-infrared tunable laser absorption spectroscopy (NIR-TLAS) as the best available technique for in-situ emission and process control measurements due to easy installation, fast response time, high accuracy, and low maintenance requirements of the sensors. Despite the huge success of NIR-TLAS sensors, there are a few limitations: for some important gases the NIR absorption line strengths and thus the sensitivities of sensors are too low (e.g. nitric oxide, NO) and some species cannot be measured at all since they do not have any absorption features in the near-infrared (e.g. sulfur dioxide).

Fundamental absorption bands in the mid-infrared spectral region (MIR) - the so called fingerprint region between 3 µm and 12 µm - are orders of magnitude stronger than the overtone and combination bands in the near-infrared which makes the MIR spectral region predestined for highly sensitive and selective measurements. However, for a long time MIR laser sources have been bulky and in many cases unreliable which precluded them from being used in almost all industrial applications. 

Fortunately, recent progress in quantum cascade lasers (QCLs) and interband cascade lasers (ICLs) made compact and reliable light sources available that are suitable for in-situ measurements even in harsh environments.

In this presentation, new sensors for process and emission monitoring of sulphur dioxide and nitric oxide sensor will be presented.