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Unformatted text preview: r) waterbased
(NH3 , HCl) compression
guard beds shift
reactor methanation MILENA as
ash/char tar recycle to combustor of
recycle to BFB or combustor of indirect gasifier Fig. 9 Existing and new parts of the SNG production facility at ECN. ECN-RX--04-085 15 CONCLUSIONS
(1) ”Green Gas” as SNG (Synthetic Natural Gas) can play an important role in the
transition process from the present Dutch fossil fuel-based energy supply to a
renewable fuel-based economy.
(2) Although upgrading of biogas, produced via anaerobic digestion of wet biomass,
will be interesting for the short-term introduction of “Green Gas” in the Dutch
energy supply, the supercritical water gasification processes seem to be more
promising for conversion of wet biomass to “Green Gas” on the longer term.
(3) Atmospheric indirect steam-blown gasification and pressurised oxygen-blown
CFB gasification are the most suitable technologies for co-production of FischerTropsch transportation fuels and SNG from biomass. Co-production is
economically more feasible than the production of both energy carriers in separate
(4) Atmospheric indirect steam-blown gasification and pressurised oxygen-blown
CFB gasification with downstream methanation are the most promising routes for
stand-alone SNG production from relatively dry biomass feedstocks, resulting in
SNG production efficiencies up to 70% LHV. Atmospheric indirect steam-blown
gasification is more suitable for decentralised (< 100 MWth) applications, while
pressurised oxygen- blown CFB gasification is more suitable for centralised (>
100 MWth) applications.
(5) The successful integrated lab-scale demonstration of “Green Gas” production
confirms the potential of the ECN gas cleanup concept to deliver a product gas
that can satisfy, among others, the specifications for downstream methanation.
(6) For a 100 MWth stand -alone system and biomass costs of 2.3 €/GJwood the SNG
production costs range from 7.8 to 8.5 €/GJSNG and the CO2 emission reduction
costs range from 83 to 95 €/tonne.
(7) Both processes of co-production of FT transportation fuels and “Green Gas” from
biomass, as well...
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- Spring '08
- Chemical Engineering