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more difficult than the pressurised oxygen-blown gasification, due to the complicated
heat exchange between the gasifier and the combustor. This makes the technology
mainly suitable for decentralised SNG plants (< 100 MWth). The fact that this
technology does not require an oxygen plant is another positive aspect of this
technology for decentralised applications. In contrary, the pressurised oxygen- blown
gasification will be more suitable for centralised applications (> 100 MWth).
With respect to biomass hydrogasification, higher SNG production efficiencies
(up to 80% LHV) and lower SNG production costs (5.6 €/GJSNG) can be achieved,
compared to biomass gasification / methanation routes. However, the limited
availability (until 2020), as well as the origin (fossil-based) of the applied hydrogen
result in lower SNG production potential and CO2 emission reduction, and higher CO2
emission reduction costs (115 €/tonne). Fossil-based hydrogen lowers the market price
for SNG from hydrogasification process, as only a part of the produced SNG can be
considered green. For hydrogasification, the availability of a sustainable and
economically attractive hydrogen source is the key to a successful implementation of
“Green Gas” production via biomass gasification, gas cleaning, and methanation was
successfully demonstrated at ECN in December 2003.
Gas cleaning is the major technical challenge in the application of product gases
from biomass gasification for SNG production, as the methanation catalysts are very
sensitive to impurities, especially sulphur, halides, and tar compounds. In the integrated
test, beech wood (1 kg/hr) was converted into a product gas by oxygen/steam- blown
gasification in one of the ECN biomass lab-scale (bubbling) fluidised bed gasifiers
(figure 7a). The composition of the product gas (main components in vol.% dry basis)
is presented in table 3. The product gas was completely de-dusted with a hightemperature ceramic filter (400°C), followed by deep tar removal with the lab-scale
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This essay was uploaded on 03/18/2014 for the course ENG 316K taught by Professor Kruppa during the Spring '08 term at University of Texas.
- Spring '08
- Chemical Engineering