Page 119 - Biomass Gasification, Pyrolysis And Torrefaction Practical Design and Theory
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Chapter | 4 Torrefaction 97
Temperature
Mass yeild
M o
Temperature Heating zone M f
Drying zone Postdrying zone Torrefaction zone Cooling zone
Heat load
Q f
Heat load
Drying zone Postdrying zone Torrefaction zone Cooling zone
Heating
Q o zone
FIGURE 4.3 Ideal temperature and mass loss history of a biomass particle undergoing torrefaction.
The heat load or energy required for this stage, Q d ,is LM f M. By taking
into account, the heat utilization efficiency of the dryer section, h u.d , the load
may be written as:
LM f M
Q d 5 (4.2)
h ud
where L is the latent heat of vaporization (B2260 kJ/kg) of water at 100 C.
The moisture fraction of the biomass as-received (M f )is M.
