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Table 1. FT Reactor Performance at H,/CO = 2 Feed When G4, A, or 3 Is Used

Table 1 FT Reactor Performance at H,/CO = 2 Feed When G4, A, or 3 Is Used

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Figure 1. A simple flowsheet of a GTL process.’
Figure 1. A simple flowsheet of a GTL process.’
Note that large amounts of water are produced in the sub- sequent FT reactor, so there is no strict limitation on the water content of cooled syngas, but it is removed for economic reasons Figure 2. Overall process flowsheet with final optimized data (@2 model, wax price = 0.63 USD/kg).
Note that large amounts of water are produced in the sub- sequent FT reactor, so there is no strict limitation on the water content of cooled syngas, but it is removed for economic reasons Figure 2. Overall process flowsheet with final optimized data (@2 model, wax price = 0.63 USD/kg).
Figure 3. Probability of chain growth to different hydrocarbons in FT reactions.°
Figure 3. Probability of chain growth to different hydrocarbons in FT reactions.°
Figure 5. FT reactor product distribution with a, from Iglesia reaction rates. Figure 4. Real roots @ asa function of the selectivity (1.2 < H,/CO < 2.15).
Figure 5. FT reactor product distribution with a, from Iglesia reaction rates. Figure 4. Real roots @ asa function of the selectivity (1.2 < H,/CO < 2.15).
Figure 7. FT reactor product distribution with a3 = 0.9.
Figure 7. FT reactor product distribution with a3 = 0.9.
Figure 6. FT reactor product distribution with a from Yermakova and Anikeev.
Figure 6. FT reactor product distribution with a from Yermakova and Anikeev.
Here, yco and yy are mole fractions in the FT reactor, and T is reactor temperature (K). The given range of operating condi- tions are H,/CO ratio from 0.5 to 4 and temperature from 423 to 803 K.'” In the rest of this Article, this value for a is denoted a. Despite the complicated appearance of eq 12, it can be easily solved for a. We call this solution @, in the rest of this Article. From its definition, @ is in the range of [0,1], and interestingly, eq 12 has only one real root in this range. Figure 4 shows the value of the real roots for a wide range of variation in the selectivity. Out of 19 roots, 16 are always imaginary, and 2 out of 3 real ones are always greater than 1. 3.1. Using Rates of Iglesia (a). From the proposed reaction rates for CO (eq 10) and CH, (eq 11), the selectivity of CH, as a function of partial pressures of H, and CO in FT reactor can be found (left-hand side of eq 12). Next, from A-9 in the Appendix, the selectivity, rceq4/rco, can be found as a function of @ (right- hand side of eq 12).
Here, yco and yy are mole fractions in the FT reactor, and T is reactor temperature (K). The given range of operating condi- tions are H,/CO ratio from 0.5 to 4 and temperature from 423 to 803 K.'” In the rest of this Article, this value for a is denoted a. Despite the complicated appearance of eq 12, it can be easily solved for a. We call this solution @, in the rest of this Article. From its definition, @ is in the range of [0,1], and interestingly, eq 12 has only one real root in this range. Figure 4 shows the value of the real roots for a wide range of variation in the selectivity. Out of 19 roots, 16 are always imaginary, and 2 out of 3 real ones are always greater than 1. 3.1. Using Rates of Iglesia (a). From the proposed reaction rates for CO (eq 10) and CH, (eq 11), the selectivity of CH, as a function of partial pressures of H, and CO in FT reactor can be found (left-hand side of eq 12). Next, from A-9 in the Appendix, the selectivity, rceq4/rco, can be found as a function of @ (right- hand side of eq 12).
Figure 8. Chain growth probability (a) as a function of H)/CO (feed) for different @ models.
Figure 8. Chain growth probability (a) as a function of H)/CO (feed) for different @ models.
Table 3. Optimal Operation When Model @, Is Used (Recommended) Table 4. Optimal Operation with Fixed @3 = 0.9
Table 3. Optimal Operation When Model @, Is Used (Recommended) Table 4. Optimal Operation with Fixed @3 = 0.9
Table 2. Optimal Operation When Model @, Is Used
Table 2. Optimal Operation When Model @, Is Used
Variable Cost the product distribution depends on the feed H,/CO ratio with models @,, @2, and @; for the chain growth probability. The operating pressure and temperature for the reactor are assumed to be 2000 kPa and 210 °C. Table 1 shows the corresponding conversion rates of CO, H, and produc- tion rates of methane and other hydrocarbons for H,/CO = 2.
Variable Cost the product distribution depends on the feed H,/CO ratio with models @,, @2, and @; for the chain growth probability. The operating pressure and temperature for the reactor are assumed to be 2000 kPa and 210 °C. Table 1 shows the corresponding conversion rates of CO, H, and produc- tion rates of methane and other hydrocarbons for H,/CO = 2.
Figure 9. Dependency of the variable income with respect to the decision variables and active constraints around the optimal nominal point (nominal data from Table S$).
Figure 9. Dependency of the variable income with respect to the decision variables and active constraints around the optimal nominal point (nominal data from Table S$).
To convert these values to more common units, the following assumptions are made:”° The proposed reaction rates by Iglesia et al. are as follows:'*
To convert these values to more common units, the following assumptions are made:”° The proposed reaction rates by Iglesia et al. are as follows:'*
Selectivity to different hydrocarbons in FT reactions is described by the well-known ASF ideal model as (A-5): where w,, is the weight fraction of C, and a@ is chain growth probability. Note that w,, is the fraction of carbon atoms reacted totally, which ends up in product with n C-atoms. This is almost (which is assumed here) but not completely the same as weight fraction.”
Selectivity to different hydrocarbons in FT reactions is described by the well-known ASF ideal model as (A-5): where w,, is the weight fraction of C, and a@ is chain growth probability. Note that w,, is the fraction of carbon atoms reacted totally, which ends up in product with n C-atoms. This is almost (which is assumed here) but not completely the same as weight fraction.”
where w25 = (1 — w, — wy — ... — Wy), and y is the olefin to parrafin ratio. Twenty reactions (C;—C 9) for paraffins and 19 reactions for olefins (C.—Cz9) are defined with weight fraction of w,, and the rest of the hydrocarbons are estimated with C,; as wax (C>,,) with weight fraction of w 5. Simplification of eq A-6 yields the weight of total hydrocarbons (kgtotal hydrocarbons/ h) a the product as eq A-8. We choose reactor volume = 2000 m’, which gives reasonable CO and Hy, conversion in our model.
where w25 = (1 — w, — wy — ... — Wy), and y is the olefin to parrafin ratio. Twenty reactions (C;—C 9) for paraffins and 19 reactions for olefins (C.—Cz9) are defined with weight fraction of w,, and the rest of the hydrocarbons are estimated with C,; as wax (C>,,) with weight fraction of w 5. Simplification of eq A-6 yields the weight of total hydrocarbons (kgtotal hydrocarbons/ h) a the product as eq A-8. We choose reactor volume = 2000 m’, which gives reasonable CO and Hy, conversion in our model.
(12) Aasberg-Petersen, K.; Bak Hansen, J. H.; Christensen, T. S.; Dybkjaer, I; Christensen, P. S.; Stub Nielsen, C.; Winter Madsen, S. E. L.; Rostrup-Nielsen, J. R. Technologies for large-scale gas conver- sion. Appl. Catal. A 2001, 221, 379-387. y (olefins to paraffins ratio) i is assumed to be an average value of 0.35 for all hydrocarbons.'* Mi AUTHOR INFORMATION
(12) Aasberg-Petersen, K.; Bak Hansen, J. H.; Christensen, T. S.; Dybkjaer, I; Christensen, P. S.; Stub Nielsen, C.; Winter Madsen, S. E. L.; Rostrup-Nielsen, J. R. Technologies for large-scale gas conver- sion. Appl. Catal. A 2001, 221, 379-387. y (olefins to paraffins ratio) i is assumed to be an average value of 0.35 for all hydrocarbons.'* Mi AUTHOR INFORMATION
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