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hand side y-axis corresponds to efficiency, while the right-hand side y-axis correspondsto moisture. For Case B, the plant efficiency increases when the live steam pressure isincreased. The moisture content at the last stage of the steam turbine is another importantissue to be taken into account.Table 1. Main parameters for design point calculations of Fig. 1.Parameter Case A Case BWood chips temperature (C) 15 15Wood chips mass flow (kg/s) 1.2 1.2Dry wood temperature (C) 150 150Gasifier temperature (C) 800 800Gasifier pressure drop 0.005 0.005Gasifier carbon conversion factor 1 1Gasifier non-equilibrium methane 0.01 0.01Steam blower isentropic efficiency 0.8 0.8Steam blower mechanical efficiency 0.98 0.98Steam temperature in the steam loop (C) 150 150Wood gas blower isentropic efficiency 0.9 0.9Wood gas blower mechanical efficiency 0.98 0.98Gas cleaner pressure drop 0.0049 0.0049Compressor air inlet temperature (C) 15 15Compressor isentropic efficiency 0.85 0.85Compressor mechanical efficiency 0.95 0.95SOFC cathode inlet temperature (C) 600 600SOFC anode inlet temperature (C) 650 650SOFC operating temperature (C) 780 780SOFC utilization factor 0.85 0.85SOFC current density (mA/cm 2 ) 300 300Heat exchangers fuel side pressure drop ratio (bar) 0.005 0.005Heat exchangers air side pressure drops (bar) 0.01 0.01Pre-Reformer inlet temperature 400C 400CPre-Reformer outlet temperature 450C 450CBurner pressure drop 0.98 0.98Water side pressure drop in super heater 0.02 0.02Water side pressure drop in evaporator 0.03 0.03Water side pressure drop in economizer 0.04 0.04HRSG outlet temperature – 90CHigh pressure steam turbine isentropic efficiency 0.9 0.9Low pressure steam turbine isentropic efficiency 0.7 0.7Extraction pressure 2 bar 2 barCondenser pressure 0.05 bar 0.05 barPumps efficiency 0.85 0.85DC/AC convertor and generators efficiency 0.97 0.97Case A: without hybrid recuperatorCase B: with hybrid recuperatorToo high level of moisture (more than about 16%) may cause blade corrosion at the laststage; see e.g. Kehlhofer et al. (1999). For Case A the moisture content was well below16% and the maximum live steam pressure could be selected without any problem forthe moisture content. For Case B, the moisture content was above the limit value of 16%when the live steam pressure was more than about 97 bars. The dashed area in the figurerepresents the area in which moisture content was beyond the limit and was not acceptedhere. However, the live steam pressure must be selected well below the limit value of 97bars in order to avoid the moisture when the plant is running on part-load or otherparameters are going to be changed. Another reason could be mentioned was due topractical problems associated with designing of such steam turbine which may occur atRisø International Energy Conference 2011 Proceedings Page 294