Future-Proof Continuous Mercury Monitoring with SICK’s MERCEM300Z

Accurate, continuous monitoring of mercury in flue gases using SICK’s innovative MERCEM300Z measurement technology sets a future-proof standard in anticipation of tougher expected European Union regulations for emissions control.

The requirements for monitoring and control of mercury emissions in Large Scale Combustion Plants, such as coal power stations, hazardous and clinical waste incineration and cement kilns, are due to be tightened for some operators following a review of the European Union’s BREF (Best Available Techniques) Reference Document.

Unique Measurement Principle

With its unique measurement principle, the MERCEM300Z continuous-flow gas analyser achieves high reliability, consistency and availability with one of the lowest EN15267-3 approved measuring ranges on the market. Its precision measurement also supports in-process control of flue gas emissions e.g. when positioned upstream of an electrostatic precipitator or scrubber.

The SICK MERCEM300Z is a compact, all-in-one converter and measurement unit that uses a patented system to monitor the total mercury content of flue gases directly where sampled. It has been industry proven to provide consistently-reliable, certified readings with the widest approved spectrum of measuring ranges, spanning 0-10/45/100/ and 1000 µg/m³.

Challenges

"Continuous mercury measurement in flue gases presents challenges for conventional measurement systems because mercury concentrations are 1000 times smaller than other flue gas components,” explains Paul Morgan, SICK UK Process Automation Specialist.

"In plants where secondary fuels are used, such as cement and energy from waste, high dust loads or high concentrations of other flue gas components can compromise some conventional conversion and measurement methods and lead to unreliable results. The MERCEM300Z’s measurement principle almost entirely eliminates cross-sensitivity due to other flue gas components.”

Meeting EN15267, TüV and MCERTS specifications, the SICK MERCEM300Z measures elemental mercury photometrically using a technique known as Zeeman atomic absorption spectroscopy, which is exclusively licensed to SICK.

Mercury can only be measured in the elemental state. So, the MERCEM300Z converts the chemically-bound mercury into free, elemental mercury at approximately 1000°C using a purely thermal process. As a result, there is no need to use chemicals, liquids or catalysts.

The hot flue gas is first extracted with a heated sample probe and transported to the analyser via a heated sample line. All components having contact with the sample gas, such as probe, sample gas line and converter in the analyser, are heated to such a high temperature that no adsorption or elution can occur. So, no mercury is lost, and the sample gas is passed unaltered to the analyser. This method avoids carry-over amalgamation effects, solids conversion, or recombination which can induce errors in conventional technology results.

Low-Maintenance

With no moving parts, and no use of chemicals, the MERCEM300Z combines high reliability with low maintenance and low operating costs. Technician intervention is minimised through automatic self-calibration of the sensor to correct drift. A fast and effective drift check can also be carried out at the press of a button. Fully-automated adjustment of the gas analyser is available through the option of a built-in test gas generator to ensure continuing measurement certainty.

For more information on the SICK MERCEM300Z mercury analyser, please contact Paul Morgan on 01727 831121 or email us.