## 2 Materials and Methods
### Simulation and Techno-Economic Analysis  
After data collection from the literature, the selected technologies included in the microalgal biomass production routes were evaluated. For this, the technologies were simulated in SuperPro Designer v10\({}^{\text{\text{\textregistered}}}\). Technologies were first simulated separately, for individual evaluation and analysis. Subsequently, the simulated technologies of each stage were combined to form the flowsheets of the 24 scenarios to be analyzed (according to Figure 1 and Table 2). The SuperPro Designer simulator handles mass and energy balances, equipment and cost sizing, economic evaluation, and many other relevant functions in process design. This Software is widely used worldwide for the simulation and design of processes, mainly in the chemical and pharmaceutical industry. The flowsheets of the process scenarios are composed of sections for the preparation of preculture and culture in a closed system (tubular photobioreactor), both sections are shown in Figure 2. It is worth mentioning that these sections are identical in all the scenarios analyzed. Figures 3-5 show the flowsheet of the harvesting (primary and secondary) and drying sections for scenarios 1, 12 and 24. Said sections are an immediate continuation of the flowsheet of Figure 2. As can be seen in the flow diagrams, the process begins with the production of the inoculum (P-1), in which the culture medium is fed through a pump (P-6). At the outlet of the P-1 unit, there is a biomass concentration of 1.5 g/L, this stream is mixed with a fresh stream of culture medium from the P-12 pump. This causes a reduction in the biomass concentration down to 0.3 g/L in stream S-102. Stream S-102 feeds the photobioreactor (P-4) at the same time as a stream of blue gases, which will provide the carbon source for the culture. Since not all the blue gas fed is consumed in the cultivation, it \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**No.** & **Scenario** & **No.** & **Scenario** & **No.** & **Scenario** \\ \hline
1 & B-C1-D1-E1 & 9 & B-C2-D1-E1 & 17 & B-C3-D1-E1 \\
2 & B-C1-D1-E2 & 10 & B-C2-D1-E2 & 18 & B-C3-D1-E2 \\
3 & B-C1-D2-E1 & 11 & B-C2-D2-E1 & 19 & B-C3-D2-E1 \\
4 & B-C1-D2-E2 & 12 & B-C2-D2-E2 & 20 & B-C3-D2-E2 \\
5 & B-C1-D3-E1 & 13 & B-C2-D3-E1 & 21 & B-C3-D3-E1 \\
6 & B-C1-D3-E2 & 14 & B-C2-D3-E2 & 22 & B-C3-D3-E2 \\
7 & B-C1-D4-E1 & 15 & B-C2-D4-E1 & 23 & B-C3-D4-E1 \\
8 & B-C1-D4-E2 & 16 & B-C2-D4-E2 & 24 & B-C3-D4-E2 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Technological scenarios to produce dry microalgae biomass. Adapted from [56]. Figure 1: Summary of technologies included in the different process stages to produce microalgae biomass. Adapted from [56]. is necessary to remove the excess. Similarly, the oxygen generated by photosynthesis must also be removed from the PBR. Both compounds are removed by the Gas Outlet stream (Figure 2). Subsequently, the PBR outlet stream (S-101), with a biomass concentration of 4 g/L, is mixed in the P-7 unit with the flocculant, according to the case (Figures 3-5). Stream S-106 feeds the clarifier (P-8), in which there are three outlet streams. Stream S-103 carries the concentrated biomass (50 g/L) and feeds the secondary harvest (unit P-9). For case D1, an additional fresh water supply is not necessary in the P-9 unit (Figure 3). On the other hand, if the filtration technologies are considered, case D2, D3 and D4 (Figures 4 and 5), it is necessary to wash the biomass and eliminate the compounds that accompany it. At the output of case D technologies, the Wet Biomass stream has a biomass concentration of 200 g/L, this stream feeds the drying technology unit (P-10) according to the case. In the P-10 unit there are two outlet streams, one with the vapors formed by the drying of the biomass and the other containing the dry biomass. Similarly, for each production scenario, a flowsheet was developed in the simulator.