harvesting stage presents a consumption of 35.37% of the total energy required for the
process. Finally, it is observed that the production of biodiesel presents the lowest
energy consumption for this case. Thus, in energy terms, the production of microalgae
oil presents a high energy consumption, due to the low yields obtained in the production of microalgae oil.
Similarly, as observed in the energy analysis, in the exergy analysis, an
exergetic consumption of 19,601,822.14 MJ/h (taken into account a feed flow of
Table 1 Investment parameters and prices used in the economic analysis
Item
Unit
Value
Ref.
Investment Parameters
Tax rate
%
25
Dávila et al. (2014)
Interest rate
%
17
Raw materials
Potassium dihydrogen phosphate
USD/kg
161
Sigma-Aldrich (n.d.)
Dibasic potassium phosphate
USD/kg
199.5
Magnesium sulfate heptahydrate
USD/kg
127.9
Iron (II) sulfate heptahydrate
USD/kg
117.9
Boric acid
USD/kg
92.4
Calcium chloride dihydrate
USD/kg
149.5
Manganese (II) chloride tetrahydrate
USD/kg
198.4
Zinc sulfate heptahydrate
USD/kg
142.4
Cupric sulfate pentahydrate
USD/kg
144
Molybdenum trioxide
USD/kg
581.9
Thiamine hydrochloride
USD/kg
426.5
Glucose
USD/kg
165
Glycine
USD/kg
94.3
Sodium hydroxide
USD/kg
111.6
Chloroform
USD/L
87.1
Methanol
USD/L
65.4
Ethanol
USD/L
0.55
ICIS (n.d.)
Utilities
LP steam
USD/tonne
1.57
Moncada et al. (2015)
MP steam
USD/tonne
8.18
HP steam
USD/tonne
9.86
Potable water
USD/m
3
1.25
Dávila et al. (2014)
Fuel
USD/MMBTU
7.21
Electricity
USD/kWh
0.1
Operation
Operator
USD/h
2.14
Dávila et al. (2014)
Supervisor
USD/h
4.29
9 Biofuels from Microalgae: Energy and Exergy Analysis for the …
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