Continuous Mercury Monitoring system (CMM)

The Gasmet CMM mercury monitoring system can measure the lowest concentrations of total mercury in samples containing high amounts of dust and gases such as SO2, which traditionally have complicated mercury measurement in e.g. installations such as coal-fired power plants stations and power plants co-incinerating refuse derived fuels. Cold Vapor Atomic Fluorescence (CVAF) offers detection of nanograms of Mercury in a cubic meter (ng/Nm3), which allows effective sample dilution. The potentially interfering SO2 absorption is completely avoided by the technique. 

A specially designed sampling system and sample dilution with nitrogen generated in the CMM cabinet ensure short response times and low memory effects for mercury. Conversion of all Mercury species (HgCl2 etc.) into atomic Mercury takes place just before the measuring cell, ensuring that the total mercury concentration is always measured accurately and reliably. The system calibrates itself automatically with nitrogen, mercury vapor and optionally also mercury chloride solution in order to comply with both European and US regulations.

 

SYSTEM PARTS

  1. Dilution probe: The Gasmet™ CMM features a dilution sample probe for the sampling of the stack gas. Also included are instrument air backflush and calibration gas inlet. Controller for the sample probe is fitted inside the analyzer cabinet for easy access. As an option, the sample probe can be fitted with an inertial filter. 

  2. Mercury Analyzer: The analyzer unit is based on the CVAF principle. Fluorescence of atomic mercury in the sample gas is measured at 254 nm (in the ultraviolet region of light). Ionic species of mercury are converted to elemental mercury with a built-in thermal converter. Built-in control panel PC enables fully automatic system control. For more information please refer to CVAF Technology.
  3. Gasmet MAUI software: Possibility to control of the CMM system also remotely.




  4. Calibration unit: The calibration unit prepares both Hgo and HgCl2 test gas. The calibration gas can be introduced to the sample probe before the particle filter, as required by the performance criteria. There is no need to use expensive calibration or dilution gases with the Gasmet™ CMM – regular instrument air is sufficient.

 

KEY ADVANTAGES

  • Very low detection limit with CVAF technique (ng/Nm3)
  • Specific for mercury – Virtually no interference from other gases such as SO2, HCl
  • Low operating costs – No need for separate chemicals, gold amalgamation concentrators, acid scrubbers, or additional gases
  • Direct sampling with sample dilution and effective filter blowback system – simple probe design
  • Reliable system with low need for maintenance

AREAS OF APPLICATION

Coal-fired power plants

  • Monitors the mass emission of mercury per amount of energy produced (mg/BTU)
  • Measures low µg/Nm3 concentrations of mercury in moderate to high SO2 matrix

Waste incinerators (Hazardous and municipal waste)

  • Monitoring mercury emissions from 0–15 µg/Nm3
  • Compliant with EU Integrated Emissions Directive and quality assurance standard EN 14884

Industrial processes with mercury in process and flue gases

  • Applicable to a wide variety of industries such as mining, metal refining, and sulphuric acid production
  • Managing mercury as an impurity arising from raw materials