PhD Thesis - Energy Systems Research Unit - University of Strathclyde

Where Biogas = Biogas production rate (kg/hr)
GasLHV = Lower heating value of biogas (kJ/Nm 3 )
GasDensity = Density of biogas (kg/Nm 3 )
Pyr = Pyrolysis oil production rate (kg/hr)
PyrDensity = Density of pyrolysis oil (kg/m 3 )
1 kWh = 3610.3 kJ
The charcoal production rate (kg/hour), and the production rates of any other
specified outputs, are as provided for a specific process and feedstock, as are the
requirements for electricity and heat (in kW).
If the amount of feedstock available at a particular timestep is between the
maximum and minimum feed rates, a linear relationship is assumed, and each of
the production rate figures is multiplied by the following partial production
factor: -
Partial Production Factor = Feed x Timesteps (6.6)
FeedRate
Where Feed = Amount of feedstock available (kg)
Timesteps = Number of timesteps per hour
FeedRate = Feedstock feed rate (kg/hr).
The heat requirement is also multiplied by this factor, as this will vary with the
amount of feedstock. The electricity requirement, however, is not reduced, as
this will remain the same, despite the reduction in feedstock. When used, the
amount of feedstock left in the store is reduced accordingly, and a tally is kept
of the overall feed used (kg), outputs made and heat and electricity required
(kWh). This information is displayed along with the final output graph.
This procedure is shown graphically in Figure 6.3, where each timestep is
considered in turn, in order to determine the fuel production rates for the
different fuels being produced, and the related energy requirements.
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