Table 5
Comparison of several convergence indicators such as the tracer, ester and alcohol outlet concentration profiles maximum peak concentrations max C(i,W) (i = t, e, a) and the tracer width at mid height 
, when using first- and second-order schemes and performing a grid refinement.
| Scheme | n | max C t,W (ppm) | max C e,W (ppm) | max C a,W (ppm) |
 (days) |
|---|---|---|---|---|---|
 (1) |
1 | 273 | 118 | 173 | 1.68 |
| 2 | 376 | 161 | 222 | 1.23 | |
| 4 | 508 | 220 | 280 | 0.92 | |
| 8 | 669 | 285 | 342 | 0.69 | |
| 16 | 831 | 361 | 417 | 0.57 | |
|
1 | 414 | 170 | 230 | 1.12 |
| 2 | 612 | 253 | 309 | 0.75 | |
| 4 | 832 | 364 | 417 | 0.56 | |
| 8 | 967 | 452 | 506 | 0.50 | |
| 16 | 999 | 491 | 552 | 0.50 | |
|
1 | 578 | 224 | 281 | 0.85 |
| 2 | 894 | 366 | 414 | 0.54 | |
| 4 | 1000 | 506 | 558 | 0.50 | |
| 8 | 1000 | 512 | 582 | 0.50 | |
| 16 | 1000 | 510 | 592 | 0.50 |