Accurate Emission Monitoring of Mercury in the Range of 1 µg/m3

It is possible to monitor mercury emissions in the range of 1 µg/m3 in Large Combustion Plants and cement kilns. These low Emission Limit Values (ELV´s) have already been introduced by the US-EPA in America. Operators can select Hg-CEMs or a Sorbent Trap Monitoring System (STMS) according to Performance Specification 12 B. As the purchase and operation of continuous mercury analysers proves to be very expensive, many operators have chosen to install continuous STMS to measure such low concentrations of mercury.

In Europe the subject is covered in the draft of the BREF document for Large Combustion Plants, Annual Emission Levels (AEL) of 2 µg/m3 for coal fired power plants. STMS´s are being seen as an alternative monitoring method to Hg-CEMs. A working group (WG8 of TC261) started three years ago on a CEN/TS for STMS, which is expected to be published by early 2017.

Environnement S.A’s AMESA-M STMS was created from the knowledge gained from 20 years of experience of continuous sampling of dioxins and furans, with the QAL1 certified AMESA D system. The AMESA-M system consists of a control cabinet connected by a heated double line to the sample probe which is mounted on the stack or duct and equipped with paired Hg-sorbent traps. The sample is extracted from the flue gas under volume proportional conditions. Gaseous mercury (elemental Hg and oxidised forms of Hg) is collected in the sorbent trap. After sampling, the traps are replaced and analysed, to determine the average mercury concentration during the sampling period.

The AMESA-M offers fully automatic sampling between 30 minutes and one month. Easy to install and use, the instrument offers user friendly HMI interface through a built in touchscreen or remotely controlled by Internet or Intranet with a TCP/IP connection; the sampling protocol can also be transferred to USB flash drive.

The AMESA-M system is available in two guises; a cabinet version monitoring distances of up to 200m between sampling probe and location of the cabinet and a compact and light (1000 x 800 x 300mm, 70kg) wall mounted version, if the system can be installed on the sampling platform.