Table 3 Summary of sensitivity analyses performed
From: Development of a sustainable process for the production of polymer grade lactic acid
No. | Equipment | Process variables | Objective variables (Sensitivity) | Base case process variable | Process variable variation range | Objective variable variation range | Optimum process variable value |
|---|---|---|---|---|---|---|---|
1 | Lactic acid separator (Separator 3) | No. of stages | Lactic acid purity (Mass fraction) | 9 | 9 - 11 | 0.99 – 0.99 | 9 |
2 | Distillate to feed | 0.5 | 0.5 - 0.7 | 0.83 – 0.99 | 0.65 | ||
3 | Reflux ratio | 1 | 1 - 1.3 | 0.99 – 0.99 | 1 | ||
4 | Feed location | 5 | 4 - 5 | 0.99 – 0.99 | 5 | ||
5 | Hydrolysis reactor | Temperature (K) | 373 | 313 - 413 | 0.62 – 0.62 | 373 | |
6 | Pure lactic acid flow (kg/hr) | 0.015 | 0.01 – 0.05 | 0.62 – 0.62 | 0.01 | ||
7 | Distilled water flow (kg/hr) | 2 | 1.8 – 2.2 | 0.65 – 0.59 | 2 | ||
8 | Bubble column reactor | No. of stages | Methyl lactate purity (Mass fraction) | 17 | 5 - 17 | 0.63 – 0.64 | 17 |
9 | Distillate to feed | 0.7 | 0.4 – 0.81 | 0.47 - 0.74 | 0.8 | ||
10 | Reflux ratio | 2 | 1 - 4 | 0.64 – 0.64 | 1 | ||
11 | Methanol feed stage | 15 | 13 - 17 | 0.59 – 0.64 | 15 | ||
12 | Heater 1 | Temperature (K) | 376 | 323 - 413 | 0.64 – 0.64 | 376 | |
13 | Heater 2 | Temperature (K) | 392 | 343 - 433 | 0.64 – 0.64 | 392 | |
14 | Splitter | Methanol recycle split fraction | 1 | 0.15 - 1 | 0.74 – 0.64 | 1 | |
15 | Methyl lactate separator (Separator 1) | No. of stages | 10 | 10 - 12 | 0.87 – 0.87 | 10 | |
16 | Distillate to feed | 0.6 | 0.1 – 0.6 | 0.67 – 0.87 | 0.6 | ||
17 | Reflux ratio | 1.5 | 1 - 3 | 0.87 – 0.87 | 1 | ||
18 | Feed location | 5 | 3 - 8 | 0.86 – 0.87 | 6 |