| 摘要 |
In a drying process for improving the filling capacity of tobacco material, the cut and humidified tobacco material is conveyed in a stream of drying gas, dried within a tubular drying section and then separated from the drying gas. At a point where it is charged into the drying section, the drying gas has a temperature of at least 200 DEG C and a flow velocity of at least 30 m/sec. The flow velocity of the drying gas is reduced in the drying section. The flow velocity of the drying gas is in this case at most 100 m/sec at the point where it is charged into the drying section. Within the drying section, the flow velocity of the tobacco material is also reduced along with the reduction in the flow velocity of the drying gas in order to reduce the local heat transfer coefficient and the local mass transfer coefficient between the surface of the tobacco material and the surrounding drying gas. At the end of the drying section, the drying gas has a flow velocity of at most 15 m/sec and a temperature of at most 130 DEG C. <IMAGE> |
