Environmental Engineering Reference
In-Depth Information
SOFC
GT systems (Roberts and Brouwer, 2006). Different groups have suggested
different system designs and characteristics, although the practical application of such
systems is still in an early stage of development.
SOFC
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GT systems running on biosyngas represent an attractive option for high-
efficiency power generation. Designing biomass gasifier
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GT systems with the
highest possible system efficiency requires detailed system studies. Currently, studies
on the development of such systems mainly start with thermodynamic evaluations,
which have indicated that net electrical efficiencies of 60
-
SOFC
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70% and total system effi-
ciencies of up to approximately 80% are achievable (Aravind et al., 2009, 2012;
Toonssen et al., 2011). An example of a system layout built in the flow sheet computer
programCycle-Tempo (tinyurl.com/mpz8cxv) is shown in Figure 16.5 (Aravind et al.,
2009). Studies of such systems clearly indicate the thermodynamic advantages of
gasifier
-
SOFC systems. However, more studies are required to clearly understand
how these systems can be optimized. Future studies should compare different system
configurations, help select suitable operating parameters for different system compo-
nents to enable optimal system performance, and reveal the effects of different gas
cleaning options on the thermodynamic performance of the system.
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16.4 CONCLUDING REMARKS
The SOFC is the most technically demanding part of a biomass gasifier
SOFC system.
Thus, the correct choice of an SOFC and its operating conditions is critical to enable
smooth functioning of gasifier
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SOFC systems. As the fuel reacts at the anode compart-
ment, the critical part of SOFC selection is the anode. The choice of gasifier depends
significantly on the scale of application. For decentralized power generation at lower
power levels of a few hundred kW, downdraft fixed bed cocurrent gasifiers may
represent a good choice, whereas for large-scale applications of a few MW, fluidized
bed gasifiers may be a better choice. The choice of gas cleaning technique depends
on the tolerance of the anode to the contaminants and the capability of the technique.
Studies indicate that systems in which gasifier, SOFCs, and GT are coupled can result in
significantly higher system efficiencies when compared with competing systems.
However, the construction of commercially viable power plants based on these
concepts requires further research and development of the technologies involved,
including the FC and gas cleaning systems, and can only be achieved after a thorough
technical and economic evaluation of the entire array of available alternatives.
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CHAPTER SUMMARY AND STUDY GUIDE
This chapter deals with the development of highly efficient energy systems based on
biomass gasification and SOFCs. In view of developing such energy systems, SOFC
components, gas cleaning options, and system integration are addressed.
Achievements obtained thus far and future study topics for developing the energy
systems are also discussed.
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