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FIGURE 8.14 Diagram of the separation process obtained from TEAM.
naphtha (corresponding to #1 and #2). Likewise, naphtha #3 and #4 represent outputs
from the system. Overall energy requirement is 7.2 MJ/h, but the inventory was
obtained taking into account that 30% of the total energy is used to produce steam.
Table 8.19 shows the inventory corresponding to the separation process. The
comments in parentheses indicate the source, compounds under consideration in a
specific group, properties or specific names for the acronyms. As can be seen, volatile
organic carbons (VOCs; as fugitive emissions) are the contribution for releases that
can be attributed to the separation process, corresponding to 79% of the total amount
of generated polluting agents (on a mass basis).

8.4.3.2 Impact Assessment

To carry out this phase of the LCA case study, the following five impact categories
have been considered: AA, WE, HT, GE and TE. The specific environmental impact
indicator used in each of the environmental impact categories mentioned before is
shown in Table 8.20.
The previously inventoried environmental loads are classified in different impact
categories. Specific characterization factors are related to each indicator to evaluate
the potential contribution of each environmental load. These factors depend on the
method used; multiplying them by the environmental loads is possible to obtain the
corresponding potential contributions.
Using the factors provided from TEAM, the results obtained can be seen in
Table 8.21.

8.4.3.3 Interpretation of the LCA
Looking at the inventory and the impact assessment results (Table 8.19 and Table
8.21) we see that the important fugitive emissions (VOC) have not resulted in any
potential impact in the LCIA phase. This is due to the fact that photochemical oxidant
formation was not chosen as an impact category for reconsideration. Evidently, by
this, the study is also an example on how important information can be lost from
the LCI to the LCIA phase by subjective choices of the LCIA indicators.

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