cyclones and the electrostatic precipitator (ESP). The separation
efficiencies of cyclone and ESP are assumed to be 99.5% and
99.9%, respectively. The particle size distributions of sand and
ash have a significant influence on sizing the cyclone and the
ESP. The average particle size of sand is 380 lm in the range from
100 to 600 lm, which was measured by experiment. Almost all
sand particles are separated in the cyclone, whereas most of ash
is removed at the ESP. It is not trivial to determine the particle size
distribution of ash after the pyrolysis reactor. In our study, the ash
particles having an average size of 38 lm range from 20 to 60 lm.
A marginal amount of ash still existing in the gas is also present in
the condensate liquid (crude biooil), resulting in a dark color. Char/
ash collected from the gas–solid separation can be sold as a byproduct.
But in this study, all char is sent to the combustor to supply
heat for the biomass pyrolysis. For excess heat, the price is set
to be 5 $/106 kJ (see Table 7).