Drytech drying machine use for drying tobacco
In recent years, more and more attentions have been paid to upgrading of the curing barns and development of alternative energy sources of coal in the wake of development of the modern tobacco agriculture. As the environmental heat-generating equipment, the heat pumps have become popular in developed countries. Chinese scientists and engineers, together with some enterprises, have made an attempt to apply the heat pump and its supporting technology to the tobacco curing process. According to the attempts, the heat pump cabinet can make full use of the air source instead of coal to dry tobacco leaves. It is proven that the quality of tobacco dried in such way has been greatly improved and the drying costs has been greatly reduced.
How to dry tobacco with DRYTECH dryer
Curing phase | Automated setting | Temperature setting (°C) | Temperature -raising rate | Drying time per phase | Total time | Change of tobacco leaves | Attentions | ||
Dry-bulb | Wet-bulb | °C/h | h | h | Yellowing degree | Drying degree | Temperature control | ||
Leaf- yellowing | The first step | 34-38 | 34-36 | 0.5-1 | 50-56 | 50-56 | Most of leaves at the upper tier yellow, but their stem is still green.
| Leaves at the upper tier get soft, and those at the lower tier emit heat. | Yellowing status: leaves at the lower tier or with higher moisture content yellow lightly; leaves at the middle and upper tier do the opposite. At the wet-bulb temperature, leaves with lower moisture content turn yellow heavily, and those with higher moisture content do the opposite. |
The second step | 40-42 | 36-38 | 0.5 | 25-30 | 75-86 | Leaves at the upper and second tier completely yellow, and those at the lower tier almost yellow. | All leaves and stems become soft. | Make sure that leaves completely yellow and are softened. Leaves at the upper tier and those with higher moisture almost yellow. | |
Color-setting | The third step | 46-48 | 36-38 | 0.3-0.5 | 20-25 | 95-111 | All leaves and their stems completely yellow. | Leaves at the upper tier roll up, and those at the lower tier roll a little. | All leaves completely yellow and roll up. Their stem yellow. The temperature is distributed evenly. |
The forth step | 52-54 | 38-40 | 0.5-0.8 | 20-24 | 115-135 | Turn the back of leaves yellow to reduce the color difference. | All leaves are rolled good except for their stem. | Extend the drying time to reduce the color difference and to facilitate leaves to roll up; and keep the temperature even. | |
Stem-drying | The fifth step | 60 | 41 | 1 | 12-14 | 127-149 |
| The stem is dried half. | Raise the temperature stably; Don’t lower the temperature; and keep the same humanity. |
The sixth step | 68 | 42 | 1 | 20-24 | 147-173 |
| The stem is dried up. | Never lower the temperature. Raise the temperature on a stable basis; don't reduce the temperature, or the water in the stem will seep; and don't increase the temperature and the humanity too highly, or the leaves will be dried red. |