Method for improving the filling capacity of tobacco

Abstract

The invention relates to a process for the improvement of the filling capacity of tobacco such as shredded tobacco leaves or ribs by treatment of the tobacco material having up to approx. 30 wt.-% initial moisture with a treatment gas composed of nitrogen and/or argon at pressures of 50 to 1,000 bar under continuous or stepped compression, followed by a continuous or stepped decompression, the compression and decompression steps taking place in either one autoclave or in cascade-like sequence in several autoclaves, and by subsequent thermal aftertreatment of the discharged tobacco material, which is characterized in that the thermal aftertreatment is carried out with a flowing heat-transferring medium of a mixture of permanent gases and superheated water vapour, wherein the proportion of permanent gas is kept constant at a value in the range from 10 to 60 vol.-%.

1 . Process for the improvement of the filling capacity of tobacco, such as shredded tobacco leaves or ribs, by treatment of the tobacco material having up to approx. 30 wt.-% initial moisture with a treatment gas composed of nitrogen and/or argon at pressures of 50 to 1,000 bar under continuous or stepped compression, followed by a continuous or stepped decompression, the compression and decompression steps taking place in either one autoclave or in cascade-like sequence in several autoclaves, and by subsequent thermal aftertreatment of the discharged tobacco material, characterized in that the thermal aftertreatment is carried out with a flowing heat-transferring medium of a mixture of permanent gases and super-heated water vapour, wherein the proportion of permanent gas is kept constant at a value in the range from 10 to 60 vol.-%.  
     
     
         2 . Process according to  claim 1 , characterized in that essentially air is used as permanent gas, and the air proportion is controlled by means of a measurement of the oxygen content.  
     
     
         3 . Process according to  claim 2 , characterized in that the air proportion of the flowing heat-transferring medium is 20 to 50 vol.-%.  
     
     
         4 . Process according to  claim 2 , characterized in that the air proportion of the flowing heat-transferring medium is 25 to 40 vol.-%.  
     
     
         5 . Process according to  claims 1  to  4 , characterized in that the temperature of the heat-transferring medium is 120 to 300° C.  
     
     
         6 . Process according to  claims 1  to  5 , characterized in that the tobacco moisture of the pressure-treated tobacco is 8 to 25 wt.-% prior to the thermal aftertreatment.  
     
     
         7 . Process according to  claims 1  to  6 , characterized in that the tobacco moisture is 8 to 15 wt.-% after the thermal aftertreatment.  
     
     
         8 . Process according to  claims 1  to  7 , characterized in that during the thermal aftertreatment, hot steam is supplied in a closed system according to the principle of stream-drying in which the permanent gas is fed in downstream from the hot-steam feed in the region of the discharge of heat-treated tobacco and is then circulated in a closed cycle with more water vapour while controlling the constancy of the proportion of permanent gas after cooling of the expanded tobacco and discharging of same.