Reduction of mercury emissions
This research group is focused on improvements towards conventional mercury reduction and especially the mercury emission reduction from burning processes (like waste incineration, sewage sludge incineration, coal burning processes in power plants), other thermal treatment processes (cement production, production of wallboards from FGD gypsum), gases from pyrolysation and natural gas.
A special point of interesst from actual projects is the oxidation of mercury in the vessel- or fluegas on both dry and wet flue gas cleaning. Non oxidized, elemental mercury (Hg0) is not soluable in water. However the ionic mercury (Hg2+) e.g. HgCl2 (as most important representative form) is good soluable in water. The wet mercury separation e.g. in a multi-stage fluegas scrubber requires a high amount of Hg2+.
In our laboratories we have several test stands for research:
- Experimental rig for low- and middle temperature oxidation of elemental mercury in gases of defined composition (150 to 800°C)
- Experimental rig to investigate the absorption and retention of elemental mercury and oxidized mercury in several scrubber stages (e.g. heavyly acid scrubbers in waste incineration, low acid FGD scrubber in coal buning power plants)
- Experimental rig fort he dry mercury pecipation of fly-ash and dry-sobents
- Experimental rig to test the sorption and desorption of mercury from SCR-DeNOx-Catalysts
For mercury emission analysis we have some portable devices:
- 4 devices for continuous mercury measurement with wet chemical reduction and CV-AAS of company DURAG / VEREWA (Type HM 1400, proved after 17. BImSchV /GMBI 1996, Nr. 28, page 592)
These devices can used for both detection of elemental mercury or oxidized mercury, depending on the wet chemical treatment. So with 2 devices (one Hg0 and one Hg2+) it’s possible to have an online analysis of the mercury speciation. The devices are used in coal burning power plants (5 to 50 µg/m³) as well as in waste incineration plants ( 5 to 1500 µg/m³).
- 2 Hg- CEMs of Seefelder Messtechnik for parallel continuous measurement of both mercury species (devices with thermal catalytic reduction and mercury up concentration with a gold trap/amalgamation)
- 1 MERCEM of SICK/MAIHAK for continuous measurement of total mercury (device with wet chemical reduction and mercury up concentration with a gold trap/amalgamation)
- 2 Hg- Analysers RA-915+ of Lumex Analytics with zeeman-effect to detect very low concentrations online, as well as solid and liquid mercury analysis
Done and ongoing projects:
- Reduction of Hg emissions of the hazardous waste incineration plant of Bayer Entsorgungszentrums Leverkusen- Bürrig (in cooperation with Vosteen Consulting GmbH)
- Reduction of mercury emissions in coal burning power plants (I cooperation with the BAYER-AG and Vosteen Consulting GmbH)
- Reduction of the mercury emissions while simultaneous combustion of waste in cement plant (in cooperation with Vosteen Consulting GmbH)
- Researching the influence of „Non-mercury“ gaseous substances (e.g. SO2, HCl, Br2) to the continuous mercury analysis to prevent errors in measurement and to improve the gaseous reduction
- Researching the influence of Na2S4 to the dry mercury precipation (in cooperation with FISIA BABCOCK ENVIRONMENT GmbH, Gummersbach)