| Catalyst |
| Strength, N/cm | Retention ratio, % |
| Fresh sample |
| 137.8 | / |
| After one | Upper part of the upper layer | 135.4 | 98.3 |
| Year’s operation | Lower part of the upper layer | 118.4 | 85.9 |
| Middle part of the lower layer | 136.9 | 99.3 |