1 Introduction
2 Analysis methods
2.1 Improvement action propositions: the case scenarios
Case scenario | Description |
---|---|
Standard (SS) | Conventional vapor power cycle at 67 bar and 480 °C |
I | Reheating vapor power cycle at 67 bar and 480 °C |
II | Regenerative vapor power cycle at 67 bar and 480 °C |
III | Reheat–regenerative vapor power cycle at 67 bar and 480 °C |
IV | Conventional vapor power cycle at 100 bar and 520 °C |
V | Reheating vapor power cycle at 100 bar and 520 °C |
VI | Regenerative vapor power cycle at 100 bar and 520 °C |
VII | Reheat–regenerative vapor power cycle at 100 bar and 520 °C |
2.2 Thermodynamic analysis
2.3 Environmental assessment
3 Goal and scope definition
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Functional unit—to the delivery of 1.0 MWh of electricity to the power grid using a cogeneration system under the conditions mentioned above.
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Product system—includes the sugarcane agricultural production stages, transport, the industrial production of ethanol, and the electricity cogeneration. The diagram of the product system appears in Fig. 1. The ethanol production rate was kept constant for all the scenarios, once the processing alternatives under study have been simulated only at the cogeneration plant, always admitting the same sugarcane crushing rate.
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Data source—secondary data served to model the product systems, with the exception of the SS, for which primary data were collected and were referred to as the equipment’s performance data.
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Data quality—the Temporal Coverage consisted of the 2-year period of 2009 and 2010. The geographical coverage comprised the state of Sao Paulo. Technical coverage considered the processes and technical features previously described.
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Allocation—the environmental load from the agricultural step and industrial process of ethanol production are allocated between ethanol and sugarcane bagasse. Thereby, it was taken into account an allocation criterion based on energy content, which was expressed in terms of the lower heating value (LHV) of the components.
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Types of impact and methodology of LCIA—to obtain an environmental performance profile with a wide spectrum as generated by grouping analytical indicators, the method ReCiPe Midpoint (H) version 1.08 was selected (Goedkoop et al. 2013).
4 Results
4.1 Thermodynamic analysis
4.2 Environmental assessment
Environmental loads | Unit | SS | I | II | III | IV | V | VI | VII |
---|---|---|---|---|---|---|---|---|---|
INPUTS | |||||||||
Inputs from nature | |||||||||
Gas, natural, and in ground | m3
| 1.12E + 01 | 1.01E + 01 | 1.05E + 01 | 9.17E + 00 | 1.02E + 01 | 9.11E + 00 | 9.60E + 00 | 8.42E + 00 |
Occupation, arable, and non-irrigated | m2a | 7.99E + 02 | 7.19E + 02 | 7.50E + 02 | 6.55E + 02 | 7.32E + 02 | 6.52E + 02 | 6.86E + 02 | 6.02E + 02 |
Oil, crude, and in ground | t | 3.04E − 02 | 2.73E − 02 | 2.85E − 02 | 2.49E − 02 | 2.78E − 02 | 2.48E − 02 | 2.61E − 02 | 2.29E − 02 |
Transformation, from arable, nonirrigated | m2
| 4.23E + 00 | 3.81E + 00 | 3.97E + 00 | 3.47E + 00 | 3.87E + 00 | 3.45E + 00 | 3.63E + 00 | 3.18E + 00 |
Transformation, from pasture and meadow, extensive | m2
| 1.75E + 01 | 1.57E + 01 | 1.64E + 01 | 1.43E + 01 | 1.60E + 01 | 1.43E + 01 | 1.50E + 01 | 1.32E + 01 |
Transformation, from shrub land, sclerophyllous | m2
| 2.21E − 01 | 1.99E − 01 | 2.08E − 01 | 1.82E − 01 | 2.03E − 01 | 1.81E − 01 | 1.90E − 01 | 1.67E − 01 |
Transformation, to arable, nonirrigated | m2
| 2.20E + 01 | 1.98E + 01 | 2.06E + 01 | 1.80E + 01 | 2.01E + 01 | 1.79E + 01 | 1.88E + 01 | 1.65E + 01 |
Water, at the surface | m3
| 1.29E + 01 | 1.14E + 01 | 1.22E + 01 | 1.03E + 01 | 1.17E + 01 | 9.99E + 00 | 1.09E + 01 | 9.25E + 00 |
Inputs from TechnoSphere | |||||||||
Agricultural machinery, general | kg | 7.28E − 01 | 6.55E − 01 | 6.84E − 01 | 5.97E − 01 | 6.65E − 01 | 5.93E − 01 | 6.24E − 01 | 5.48E − 01 |
Ammonium nitrate phosphate, as N | kg | 7.56E − 01 | 6.80E − 01 | 7.10E − 01 | 6.20E − 01 | 6.91E − 01 | 6.15E − 01 | 6.48E − 01 | 5.69E − 01 |
Diesel | kg | 1.75E + 01 | 1.58E + 01 | 1.64E + 01 | 1.44E + 01 | 1.60E + 01 | 1.42E + 01 | 1.50E + 01 | 1.32E + 01 |
Carbofuran | kg | 3.83E − 02 | 3.45E − 02 | 3.60E − 02 | 3.14E − 02 | 3.50E − 02 | 3.12E − 02 | 3.28E − 02 | 2.88E − 02 |
Diuron | kg | 8.90E − 03 | 8.01E − 03 | 8.36E − 03 | 7.30E − 03 | 8.13E − 03 | 7.24E − 03 | 7.63E − 03 | 6.70E − 03 |
Fipronil | kg | 3.65E − 03 | 3.29E − 03 | 3.43E − 03 | 2.99E − 03 | 3.34E − 03 | 2.97E − 03 | 3.13E − 03 | 2.75E − 03 |
Glyphosate | kg | 2.08E − 02 | 1.87E − 02 | 1.95E − 02 | 1.71E − 02 | 1.90E − 02 | 1.69E − 02 | 1.78E − 02 | 1.57E − 02 |
Growth regulators | kg | 7.71E − 03 | 6.94E − 03 | 7.24E − 03 | 6.32E − 03 | 7.05E − 03 | 6.28E − 03 | 6.61E − 03 | 5.81E − 03 |
Harvester | kg | 2.46E − 01 | 2.21E − 01 | 2.31E − 01 | 2.02E − 01 | 2.25E − 01 | 2.00E − 01 | 2.11E − 01 | 1.85E − 01 |
Lime, hydrated and packed | kg | 4.55E + 00 | 4.10E + 00 | 4.27E + 00 | 3.73E + 00 | 4.16E + 00 | 3.70E + 00 | 3.90E + 00 | 3.43E + 00 |
Potassium chloride, as K2O | kg | 6.09E + 00 | 5.48E + 00 | 5.72E + 00 | 4.99E + 00 | 5.57E + 00 | 4.96E + 00 | 5.22E + 00 | 4.59E + 00 |
Single superphosphate, as P2O5
| kg | 2.74E + 00 | 2.47E + 00 | 2.57E + 00 | 2.25E + 00 | 2.50E + 00 | 2.23E + 00 | 2.35E + 00 | 2.06E + 00 |
Urea, as N | kg | 5.02E + 00 | 4.52E + 00 | 4.71E + 00 | 4.12E + 00 | 4.59E + 00 | 4.09E + 00 | 4.30E + 00 | 3.78E + 00 |
Tractor | kg | 5.12E − 01 | 4.61E − 01 | 4.81E − 01 | 4.20E − 01 | 4.68E − 01 | 4.17E − 01 | 4.39E − 01 | 3.86E − 01 |
Vinasse, from sugarcane | m3
| 7.15E + 00 | 6.44E + 00 | 6.71E + 00 | 5.86E + 00 | 6.54E + 00 | 5.82E + 00 | 6.13E + 00 | 5.38E + 00 |
OUTPUTS | |||||||||
Emissions to air | |||||||||
NH3
| kg | 2.19E + 00 | 1.97E + 00 | 2.05E + 00 | 1.79E + 00 | 2.00E + 00 | 1.78E + 00 | 1.88E + 00 | 1.65E + 00 |
Cd | kg | 1.61E − 04 | 1.45E − 04 | 1.51E − 04 | 1.32E − 04 | 1.48E − 04 | 1.31E − 04 | 1.38E − 04 | 1.21E − 04 |
Carbon dioxide, biogenic | kg | 1,32E + 03 | 1.18E + 03 | 1.23E + 03 | 1.08E + 03 | 1.20E + 03 | 1.07E + 03 | 1.13E + 03 | 9.90E + 02 |
CO2, fossil | kg | 1.50E + 02 | 1.35E + 02 | 1.41E + 02 | 1.23E + 02 | 1.37E + 02 | 1.22E + 02 | 1.29E + 02 | 1.13E + 02 |
CO2, land transformation | kg | 2.94E + 02 | 2.65E + 02 | 2.76E + 02 | 2.41E + 02 | 2.69E + 02 | 2.40E + 02 | 2.52E + 02 | 2.21E + 02 |
CO, biogenic | kg | 2.20E + 01 | 1.98E + 01 | 2.06E + 01 | 1.80E + 01 | 2.01E + 01 | 1.79E + 01 | 1.89E + 01 | 1.66E + 01 |
CO, fossil | kg | 8.30E + 01 | 7.47E + 01 | 7.79E + 01 | 6.81E + 01 | 7.60E + 01 | 6.77E + 01 | 7.12E + 01 | 6.25E + 01 |
Cu | kg | 2.62E − 02 | 2.36E − 02 | 2.46E − 02 | 2.15E − 02 | 2.40E − 02 | 2.13E − 02 | 2.25E − 02 | 1.97E − 02 |
CH4
| kg | 3.54E − 01 | 3.19E − 01 | 3.32E − 01 | 2.90E − 01 | 3.24E − 01 | 2.89E − 01 | 3.04E − 01 | 2.67E − 01 |
CH4, biogenic | kg | 6.59E − 01 | 5.93E − 01 | 6.19E − 01 | 5.40E − 01 | 6.03E − 01 | 5.37E − 01 | 5.66E − 01 | 4.96E − 01 |
CH4, fossil | kg | 2.13E + 00 | 1.92E + 00 | 2.00E + 00 | 1.75E + 00 | 1.95E + 00 | 1.74E + 00 | 1.83E + 00 | 1.61E + 00 |
N2O | kg | 2.18E + 00 | 1.96E + 00 | 2.05E + 00 | 1.79E + 00 | 2.00E + 00 | 1.78E + 00 | 1.87E + 00 | 1.64E + 00 |
NMVOC, unspecified origin | kg | 4.61 + 01 | 4.15E + 01 | 4.33E + 01 | 3.78E + 01 | 4.22E + 01 | 3.76E + 01 | 3.95E + 01 | 3.47E + 01 |
Particulates, <10 um | kg | 2.83E + 00 | 2.55E + 00 | 2.66E + 00 | 2.32E + 00 | 2.59E + 00 | 2.31E + 00 | 2.43E + 00 | 2.13E + 00 |
Particulates, <2.5 um | kg | 8.25E + 01 | 7.43E + 01 | 7.75E + 01 | 6.76E + 01 | 7.55E + 01 | 6.73E + 01 | 7.08E + 01 | 6.21E + 01 |
SO2
| kg | 1.59E + 01 | 1.43E + 01 | 1.49E + 01 | 1.30E + 01 | 1.46E + 01 | 1.30E + 01 | 1.36E + 01 | 1.20E + 01 |
Zn | kg | 1.55E − 02 | 1.39E − 02 | 1.45E − 02 | 1.27E − 02 | 1.42E − 02 | 1.26E − 02 | 1.33E − 02 | 1.17E − 02 |
Emissions to water | |||||||||
Fipronil | g | 5.47E − 02 | 4.92E − − 02 | 5.14E − 02 | 4.48E − 02 | 5.01E − 02 | 4.46E − 02 | 4.69E − 02 | 4.12E − 02 |
PO4
3–
| g | 8.67E + 01 | 7.80E + 01 | 8.15E + 01 | 7.11E + 01 | 7.94E + 01 | 7.06E + 01 | 7.45E + 01 | 6.54E + 01 |
P | g | 1.09E + 00 | 9.84E − 01 | 1.03E + 00 | 8.96E − 01 | 1.00E + 00 | 8.91E − 01 | 9.38E − 01 | 8.23E − 01 |
Emissions to soil | |||||||||
Cd | g | 1.10E − 01 | 9.94E − 02 | 1.04E − 01 | 9.05E − 02 | 1.01E − 01 | 9.00E − 02 | 9.47E − 02 | 8.32E − 02 |
Carbofuran | g | 3.77E + 01 | 3.40E + 01 | 3.54E + 01 | 3.09E + 01 | 3.45E + 01 | 3.08E + 01 | 3.24E + 01 | 2.84E + 01 |
Diuron | g | 8.77E + 00 | 7.89E + 00 | 8.23E + 00 | 7.19E + 00 | 8.02E + 00 | 7.15E + 00 | 7.52E + 00 | 6.60E + 00 |
Fipronil | g | 3.59E + 00 | 3.23E + 00 | 3.37E + 00 | 2.94E + 00 | 3.29E + 00 | 2.93E + 00 | 3.08E + 00 | 2.71E + 00 |
Impact category | Unit | Case scenarios | |||||||
---|---|---|---|---|---|---|---|---|---|
SS | I | II | III | IV | V | VI | VII | ||
CC | kg CO2
eq
| 1.17E + 03 | 1.05E + 03 | 1.10E + 03 | 9.60E + 02 | 1.07E + 03 | 9.55E + 02 | 1.00E + 03 | 8.82E + 02 |
TA | kg SO2
eq
| 2.24E + 01 | 2.01E + 01 | 2.10E + 01 | 1.83E + 01 | 2.05E + 01 | 1.82E + 01 | 1.92E + 01 | 1.69E + 01 |
FEu | kg P eq
| 2.54E − 02 | 2.29E − 02 | 2.39E − 02 | 2.09E − 02 | 2.33E − 02 | 2.07E − 02 | 2.19E − 02 | 1.92E − 02 |
HT | kg 1,4-DB eq
| 4.71E + 01 | 4.23E + 01 | 4.42E + 01 | 3.86E + 01 | 4.31E + 01 | 3.83E + 01 | 4,04E + 01 | 3.54E + 01 |
POF | kg NMVOC | 5.47E + 01 | 4.92E + 01 | 5.13E + 01 | 4.48E + 01 | 5.00E + 01 | 4.46E + 01 | 4.69E + 01 | 4.12E + 01 |
PMF | kg PM10
eq
| 8.97E + 01 | 8.07E + 01 | 8.42E + 01 | 7.35E + 01 | 8.21E + 01 | 7.31E + 01 | 7.69E + 01 | 6.75E + 01 |
TEc | kg 1,4-DB eq
| 3.43E + 00 | 3.08E + 00 | 3.22E + 00 | 2.81E + 00 | 3.13E + 00 | 2.79E + 00 | 2.94E + 00 | 2.58E + 00 |
FEc | kg 1,4-DB eq
| 1.41E + 00 | 1.27E + 00 | 1.32E + 00 | 1.16E + 00 | 1.29E + 00 | 1.15E + 00 | 1.21E + 00 | 1.06E + 00 |
ALO | m2a | 8.03E + 02 | 7.22E + 02 | 7.53E + 02 | 6.58E + 02 | 7.35E + 02 | 6.54E + 02 | 6.89E + 02 | 6.04E + 02 |
NLT | m2
| 5.21E − 02 | 4.68E − 02 | 4.89E − 02 | 4.26E − 02 | 4.76E − 02 | 4.24E − 02 | 4.46E − 02 | 3.92E − 02 |
WD | m3
| 1.43E + 01 | 1.26E + 01 | 1.35E + 01 | 1.14E + 01 | 1.29E + 01 | 1.11E + 01 | 1.21E + 01 | 1.03E + 01 |
FD | kg oil eq
| 2.38E − 04 | 2.15E − 04 | 2.24E − 04 | 1.95E − 04 | 2.18E − 04 | 1.94E − 04 | 2.05E − 04 | 1.80E − 04 |