PhD Thesis - Energy Systems Research Unit - University of Strathclyde

For each process, the process characteristics (except for the fuel availability
information) are defined in a separate window, in the same manner as described
previously for the different processes. This window appears when the option to
use the process is chosen, and examples of these windows are given in
Appendix 1, Figure A1.18 and A1.19. The outputs and energy use are
calculated in the same manner as described in Section 6.1 for gasification, and
Section 6.2 for anaerobic digestion, and the various options for processing the
resulting gas are also available. The relevant production rate graphs are given
along with the biodiesel production graph and the relevant overall production
and use figures are also given. The maximum required storage and the amount
of feedstock remaining are given for the gasification process, and a second
simulation period is, again, analysed, as required, if there is a substantial amount
of feedstock remaining at the end of the period.
6.4 Fermentation
Fermentation is the production of ethanol from sugary, starchy or cellulosic
materials. The feedstock for this process may be continuously available (waste
fruit, newspapers etc), or seasonal (energy crops). Small-scale production is
batch-wise, and larger scale production may be achieved through various
continuous processes [7,8]. An example of the fermentation system definition
window is given in Appendix 1, Figure A1.17.
6.4.1 Feedstock Availability
Feedstock availability, for continuous and seasonal supplies, is dealt with as
described in Section 6.1.1 and Figure 6.1. The electricity and heat required for
the pre-processing of feedstock, however, are not calculated here as these are
considered later as part of the ethanol production process. Only one type of
feedstock may be used in a particular process simulation, as the process outputs
and requirements vary with different feedstocks. It is possible, however, to have
a number of different harvests of the same energy crop per year, so up to five
different harvest times may be specified for the one feedstock type.
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