Clean-Air Technology

Catalytically thermal disposal of methane-lean gases (MethaKat)

The project participants research processes for suitable disposal of gases containing methane, which are produced primarily in waste dumpsites and former bituminous coal mines. These climate-damaging gases are presently not treated if their methane content does not reach at least 25 volume percent. The untreated gases are thus released to the atmosphere. The project result is a successful method for thermal disposal of methane-lean gases by means of a catalyst.

Summary

The impact of methane (CH4) as a greenhouse gas is 23 times greater than that of CO2. Methane thus makes up a substantial share of harmful greenhouse gas emissions. In Germany, CH4 pollution occurs mainly through waste dumping and escaping mine gas. Disposal is particularly difficult in the case of dumpsite and mine gas phases with a CH4 concentration of less than 25%. Above this threshold, suitable disposal does not pose any problems.
The project aimed to develop a successful method for assisted thermal disposal of CH4-lean gases (CH4 content < 25 vol. %). Ceramics-borne catalysts are suitable for disposal of the gases as they facilitate stable combustion of lean gases. The project aims to develop and optimise such catalysts.
First, a stable material combination of substrate material and catalyst was developed at laboratory scale. The catalytic system developed consists of the components substrate (open-pore foamed ceramic), coating (calcium aluminate) and impregnation with an active ingredient (metal oxide). Based on examinations of the catalytic and thermal effects in the laboratory, a pilot plant was commissioned for testing of the new technology's capacity for application. The plant was run under realistic conditions with a varying gas composition. The project's results demonstrate the developed technology's potential for disposal of CH4-lean gases.

Results:

  • Ceramic foams made of sintered silicon carbide (SSiC) were identified as a suitable substrate material.
  • The ceramic support layer of the catalyst displayed the best mechanical stability as well as a suitable effective surface at a pore size of 20 ppi.
  • Calcium aluminate was found to be the ideal active catalytic coating.
  • A sintering temperature of 1,200 °C guarantees sufficiently high catalyst activity.
  • Doping the catalyst with manganese oxide increases resistance to deactivation through sulphuric acid (H2S) and sulphur oxide (SO2).
  • The pilot plant was able to achieve almost complete methane conversion (99.9%).

More Project Informations

Project title: Katalytisch-thermische Entsorgung methanhaltiger Schwachgase - MethaKat

Project number: 01LS05016

Project period: 2006 - 2010

Project region: Germany (Saxony)

Project contact:

Herr Dipl.-Krist. Adler
+49 (0) 351 2553-7515
+49 (0) 351 2554-333

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Source: German National Library of Science and Technology Hannover (TIB)