Tobacco Leaf Dryer

Advantage

1、Fast heating, high energy efficiency

2、Special tobacco controller could control the drying time, temperature and other devices more precisely and accurately

3、Environmental protection, economical and practical, flexible installation, wide application range, low operating cost

4、Closed-cycle drying under normal pressure and low temperature, and the drying quality is good

5 、Clear appearance, low noise, long service life

Schematic diagram of working principle of split air energy drying equipment

According to the national three-stage tobacco leaf curing process standard for flue-cured tobacco, combined with the working principle of the steam absorption heat pump system, Shuntec Group has launched a tobacco leaf drying process standard with Shuntec characteristics after repeated experiments and demonstrations with experts in the tobacco leaf curing field. The whole drying process is divided into three stages: yellowing stage, color fixing stage and stem-drying stage. The use of Shuntec heat pump dryers for flue-cured tobacco is environmentally friendly, safe and energy-saving. At the same time, the temperature and humidity control during the flue-curing process is very stable, which improves the quality of tobacco leaves and brings greater economic benefits.

Yellowing stage

The starting temperature is 32 degrees, and the temperature is increased by 1 ℃ per hour to 35-36 ℃ (notice: it shall maintain the differences of dry temperature and wet temperature within 1-2 ℃), and the temperature is stabilized until the tobacco leaves are softened and collapsed (generally, the lower leaves need 10-15 hours, the middle leaves 15 -20 hours, and upper leaves 20-25 hours). Afterwards, the temperature should increase to 38-39°C, and the wet bulb temperature should be kept at 36-37°C. The temperature should be stabilized until the tobacco leaves turn yellow. When the tobacco leaf becomes yellow with green stem, the temperature should heat up to 42°C and the wet bulb temperature should keep within 37°C and should stabilized for 10-15 hours to dehumidify in advance, then the temperature is increased to goes into the color fixing period. Generally, it will cost 60-72 hours for the lower leaves to turn yellow, 48-60 hours for the middle leaves, and 36-48 hours for the upper leaves.)

Fixing stage

After the tobacco leaves turn yellow with green stem, and the leaves become softened, the temperature of the drying room is raised to 45-48℃ at a rate of increasing 1℃ every 2-3 hours. The wet bulb temperature is controlled within 37-39℃to make the tobacco leaves turned into yellow slices with yellow stems and becomes small rolls. Afterwards, the temperature should heat up to 50-52°C, and the wet bulb temperature should control within 38-40°C to make the tobacco leaves are tipped into large roll, and then the temperature should heat up to 54-55°C (wet bulb is 38-40°C) for more than 12 hours in order to reduce the color difference between the front and back of the tobacco leaf. The moisture and temperature of the drying room which is loose leaf stacked-type shall meet the minimum humidity standard, and the wet bulb’s temperature can not exceed the requirements in the whole period (quasi low is not high).

For tobacco leaves with large differences in quality, it is required to prolong the drying time at the temperature of 45-48°C as long as possible, and then heat up after the tobacco stems are completely turn yellow, so as to reduce the production of dried tobacco with green stems.

Stem-drying stage

After the tobacco leaves meet the color fixation requirements, it should quickly raise the dry bulb‘s temperature to above 60°C, the highest temperature cannot exceed 68°C, and the highest wet bulb’s temperature cannot exceed 43 °C (generally 39-42 °C). It usually costs 30-40 hours for drying the tobacco stems completely.

Schematic diagram of the working principle of tobacco air drying equipment

Case picture