PhD Thesis - Energy Systems Research Unit - University of Strathclyde

At the end of the simulation, graphs of the ethanol production rate and energy
demands are created. Information about the overall consumption of feedstock,
other inputs, electricity and heat, and the overall production of ethanol, other
outputs, and crop residue are given. The amount of unprocessed feedstock
remaining and maximum storage required at any given time throughout the
simulation are also presented. This process is shown in Figure 6.7.
6.4.3 Batch Process Characteristics
The batch process for ethanol production is started each day at a specified time,
provided there is sufficient feedstock and equipment available. As the
fermentation process may take between two to four days to complete, it is
common to have a number of different fermenters available, to allow new
batches to be started each day. The following process information is required to
create the temporal fuel production and energy use profiles.
• The time for one batch (hours).
• The number of fermenters available.
• The maximum and minimum feedstock input per batch (litres).
• Any other inputs required (e.g. yeast, water, malt), type, amount and
units.
• The ethanol output (litres).
• The wet and dry animal feed outputs (kg).
• Any other outputs (e.g. carbon dioxide), type, amount and units.
The energy requirements for the batch process occur at different times
throughout the process, and may include the following demands, in this order.
• Electricity for the crushing or milling of the feedstock (kW).
• Heat for cooking and/or electricity for mixing (kW).
• Heat for hydrolysis and/or electricity for mixing (kW).
• Cooling requirement (heat or electricity) during fermentation (kW).
• Heat for distillation (kW)
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