Table 1
The drying conditions and their corresponding equilibrium moisture content in tobacco on dry basis Xe (28).
| Drying conditions | Tobacco equilibrium moisture content (%) | |
|---|---|---|
| Temperature (K) | Relative humidity (%) | |
| 338.15 | 0.115 | 0.048 |
| 358.15 | 0.050 | 0.035 |
| 378.15 | 0.024 | 0.027 |
| 398.15 | 0.012 | 0.022 |
| 418.15 | 0.007 | 0.018 |
Table 2
Mathematical models of equilibrium moisture content.
| Name of the model | Equation | |
|---|---|---|
| Henderson | (Hen) | |
| Modified Henderson | (M-Hen) | |
| Modified Oswin | (M-Osw) | |
| Chung-Pfost | (C-P) | |
| Modified Chung-Pfost | (M-C-P) | |
| Halsey | (Hal) |
Table 3
Estimated coefficients and criteria for comparing EMC models for cut tobacco.
| Parameter | Henderson | Modified Henderson | Modified Oswin | Chung-Pfost | Modified Chung-Pfost | Halsey |
|---|---|---|---|---|---|---|
| A | 3.5239 | −0.9313 | −0.0914 | 3397.00 | 1.63·105 | 22.6107 |
| B | 3.0239 | −516.0073 | 0.0006 | 32.1078 | 2.09·104 | 1.1462 |
| C | 0.4210 | 0.4553 | 26.4425 | |||
| RMSE | 0.0010 | 0.0004 | 0.0004 | 0.0029 | 0.0015 | 0.0018 |
| MRD | 0.0554 | 0.0255 | 0.0172 | 0.1751 | 0.0940 | 0.1052 |
Figure 1
Comparison between experimental data and simulations given by M-Hen/Classic model at varying weight factor r values.
Figure 2
Comparison between RMSE and MRD at various weight factor r values ranging from 0.9 to 0.01. Model: M-Hen/Classic model.
Figure 3
Coefficients of km and kh at different weight factor r values in the range of 0.9 to 0.01. Model: M-Hen/Classic model.
Figure 4
Comparison between experimental data and simulations given by different models.
Figure 5
Comparison between RMSE and MRD values under different heat and mass transfer models.
Figure 6
Coefficients of km and kh for different heat and mass transfer models.
Figure 7
Comparison of RMSE and MRD values of models for various drying conditions.
| Nomenclature | |
|---|---|
| A, B, C | Parameter in equilibrium model |
| Cp | Specific heat capacity (J·kg−1·K−1) |
| hAm | Heat transfer coefficient (W·kg−1·K−1) |
| hm Am | Mass transfer coefficient (m3·kg−1·s−1) |
| M | Molecular weight (kg·mol−1) |
| MRD | Mean relative deviation |
| p | Vapor pressure (Pa) |
| R | Universal gas constant (J·mol−1·K−1) |
| RH | Relative humidity (1) |
| ρ | Vapor density (kg−1·m−3) |
| Subscripts | |
| b | Hot gas |
| cal | Calculated value |
| e | Equilibrium zone |
| exp | Experimental value |
| t | Cut tobacco |
| w | water |