PCME STACK 181 WS


The PCME STACK 181 WS is suitable for measuring particulate emissions from wet scrubbers and other processes where the flue gas falls below dew point (cold stack conditions) or water droplets are present. The extractive instrument takes a representative continuous sample from the stack, heats this well above dew point to evaporate water droplets and then measures the particulate concentration under dry conditions. This extractive approach with heating overcomes the problems of interference from condensation and water droplets associated with using in-situ particulate monitors after wet collectors.


The PCME STACK 181 WS uses an advanced ProScatter Forward Scatter sensor (PCME QAL 181) which is certified by TUV and MCERTS as QAL1 compliant. With certification ranges covering both 0-15mg/m3 and 0-100mg/m3, the sensor is suitable for monitoring the highly abated emissions found after Flue Gas Desulphurisation plant (FGD). The instrument is able to monitor saturated flue gas which is critical for the application of monitoring emissions from a coal fired power plant fitted with a wet FGD system and meets the requirements of PS-11 and EN 14181.


The patented ProScatter™ Forward Scatter technique measures the light scattered from a laser source in a near-forward direction by the particles, and results in an improved signal to noise ratio compared to other techniques, with excellent resolution and zero drift characteristics. This allows for high stability even at low concentrations (< 0.1 mg/m3) as well as rugged operation in stacks where emissions exceed 100 mg/m3.

  • Highly sensitive (<0.1mg/m3) and rugged instrument for measuring particulate concentrations in wet flues
  • Extensive system self-checks including vaporising chamber and sampling pump, with logging of Zero and Span check data for QAL3 reporting, manual audit functionality
  • Modular design to facilitate ease of assembly, servicing and lifting to stack location
  • Isokinetic sampling with automatic adjustment to maintain isokinetic conditions (requires input from external flow meter)


Two other versions of the Wet Stack Monitoring System are also available, the PCME QAL 181 WS and the PCME VIEW 181 WS. The PCME QAL 181 WS is certified by TUV to EN 15267-3 with QAL 1 as defined by EN 14181 with a certification range of 0 - 15 mg/m3. The PCME VIEW 181 WS is suitable for applications that do not require QAL 1 certification.