Methanation

Large-scale methanation of coal is a mature technology and has been investigated for approximately 70 years particularly in Germany [6]. A large commercial plant for the gasification of lignite – the Great Plains Synfuels Plant, Dakota Gas, Company  – is operating in the USA since 1984 [7].  Oxygen-blown fixed  bed  gasifiers  with  a  thermal  capacity  of  16000  t  per  day  (i.e.  approx.  3  GW  thermal  input) produce syngas, which is converted into synthetic natural gas with a lower heating value of approx. 36300 kJ/m³. 

Several ongoing projects actually focus on the production of substitute Natural gas from Biomass. The methanation of biomass-derived syngas has been investigated with lab-scale tests at the Gasification plant in Güssing [1] successfully. The tests continue presently at a 1 MW scale within the European
BioSNG project [8]. Investigations with an oxygen blown gasifier have been performed within ECNs Milena  project  [9].  These  technologies  are  based  mainly  on  steam-blown  gasifiers  (allothermal/ indirect gasification) due to a more favourable CO/H2 ratio of the raw gas after the gasification.

Methanation Flowsheet

Figure 2: Methanation system with indirect (allothermal) gasification

 

[1]  Karl, J. Frank, N., Karellas, S. Saule, M., Hohenwarter, U., Conversion of Syngas from biogas in solid oxide fuel cells, Proceedings of
FUELCELL2006, June 19-21, 2006, Irvine, CA

[6]  Mansour et. al., “  Indirectly heated Thermochemical reactor apparatus and process”, US-Patent No. 5306481, 1994
[7]   www.heatpipe-reformer.com
[8]  Friedrichs,G.:Methanisierung von Kohlevergasungsgasen im Wirbelbett Pilot-Entwicklungsstufe; Bundesministerium für Forschung
und Technologie; Forschungsbericht T 85-106; 1985
[9]  www.dakotagas.com, 1.6.2008