PhD Thesis - Energy Systems Research Unit - University of Strathclyde

The output obtained when a second harvest period with larger feedstock
availability is defined is shown in figure 7.14. If this allows some feedstock to
be carried over and used during the next harvest period, the production graph
obtained is shown in Figure 7.15, showing that the feedstock is being correctly
stored and used as necessary. Again, the magnitudes and timing of the supplies
and demands are tested by calculation, and against the input times.
If crop residues are sent to the anaerobic digester, these parameters are set as
shown in Figure 7.16, and the outputs produced and energy required are shown
in Figures 7.17 and 7.18. These show that the extra heat and electricity required
for the digestion process are being added at the correct times, and in the
appropriate quantities. The biogas output from the digestion process is also
calculated correctly and given over the appropriate time, with start-up and
shutdown periods being dealt with according to the assumptions made in
Chapter 6. If other residues are sent to the anaerobic digester, the process
parameters are defined separately, and the model is tested to ensure that outputs
of the same type are combined correctly. The anaerobic digestion of all three
residue types is tested individually and in combination to ensure proper
calculation and combination of outputs and demands. This process is also
repeated for the gasification of residues, both individually and in combination.
Where different uses of the output biogas are specified, the expected outputs are
calculated and compared with the given results.
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