JP3851269B2 - Tobacco filling capacity improvement method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for improving the filling capacity of tobacco according to the preamble of the main claim.
[0002]
[Prior art]
In improving the filling capacity of tobacco, for example, the INCOM swelling method according to DE 3119330 A1, DE 3414625 C2 and DE 3935774 C2 has been successful. In these methods, a pressure of 50 to 1,000 bar is applied with a processing gas consisting of nitrogen and / or argon, for example in the form of chopped tobacco leaves or veins, with an initial moisture of up to about 30% by weight. Compress continuously or stepwise and then depressurize continuously or stepwise. This compression and decompression step is performed in one autoclave or in several cascade autoclaves. The discharged tobacco material is then post-treated with heat, causing the tobacco to swell and the tobacco filling capacity to increase.
[0003]
These INCOM methods have proven advantageous over pressure treatments of tobacco with carbon dioxide, ammonia or volatile organic compounds. The latter method must accept undesired elution of fragrance components or nicotine from the tobacco material, or if gaseous residues in the tobacco material impair the flavor or use carbon dioxide, the dry matter produced after decompression This is because removing ice eventually consumes excessive energy.
[0004]
For the INCOM method described above, DE 3119330 describes such an expansion method, mainly using an operating temperature of 0-50 ° C. in an autoclave. In this method, tobacco materials containing up to 15% by weight of water were used to increase the filling capacity or degree of swelling and were post-treated with steam. Furthermore, DE 3414625 C2 and DE 3935774 C2 disclose cascade processes, according to which the tobacco impregnation is effected by cooling the process gas before charging the reactor, cooling the autoclave, or by using supercooled and liquefied process gas. A low working temperature is obtained.
[0005]
In these known methods, the aftertreatment with heat is carried out with steam of 0.5 to 10 kg (m ³ density, preferably saturated steam, or with hot air up to 440 ° C.
[0006]
A method for treating tobacco with carbon dioxide at a pressure of about 30 bar is known from EP 484899 B1, but according to this method, the thermal post-treatment is carried out after heating the tobacco in a fluid medium at 200-350 ° C. It is carried out by feeding into hot steam or into a gas containing 50 to 95% by volume of steam, and the lower temperature water or steam downstream from the tobacco feed point is the temperature of the fluidized medium. Used to reduce Tobacco that has been dried to about 2-3 wt% moisture with a heat transfer fluid medium is then reset to normal moisture. Since pressurization of tobacco with carbon dioxide after depressurization produces dry ice, the cigarette must be rapidly heated for post-treatment of the cigarette with heat, regardless of the high evaporation enthalpy of dry ice. This can be a significant thermal and / or mechanical stress for tobacco.
[0007]
[Problems to be solved by the invention]
In the case of the INCOM method on which the present invention is based, tobacco treated with nitrogen and / or argon is required for desorption of the absorbed gas and the associated swelling of the tobacco compared to tobacco treated with CO _2. Energy is much lower. Therefore, in the case of the INCOM method, in contrast to the CO ₂ method, there is no adverse effect on the flavor. In addition, in the case of heat treatment of tobacco treated with nitrogen and / or argon, heat is transferred by condensation of water vapor into the cooled tobacco, and further heat treatment causes the desired moisture content of the expanded tobacco. The content is achieved by drying.
[0008]
Nevertheless, the INCOM process has the risk of excessive humidification and overheating of the tobacco, resulting in loss of filling capacity due to collapse of the expanded cell structure.
[0009]
It is an object of the present invention to provide a thermal post-treatment to achieve a uniform product quality with optimal filling capacity when post-treating tobacco treated with nitrogen and / or argon in the INCOM process. is there.
[0010]
[Means for Solving the Problems]
Therefore, in order to achieve this objective, a method according to the main claim statement is presented, which is a fluid heat transfer medium consisting of a mixture of permanent gas and superheated steam, with a permanent gas proportion of The heat treatment is carried out with a fluid heat transfer medium that is kept constant at a value in the range of 10-60% by volume.
[0011]
Permanent gas means in this text a gas such as air that can be used with water vapor during drying and may be mixed with nitrogen and / or argon or other inert gases.
[0012]
Surprisingly, the percentage of permanent gas in the mixture with superheated steam is clearly an indispensable parameter to achieve the optimum filling capacity value under the given working conditions, especially in the flow drying process. It has become.
Preferably, air is used essentially as a permanent gas and the proportion of air is indirectly controlled by measuring the oxygen content. The proportion of air in the fluid heat transfer medium is preferably 20-50% by volume, in particular 25-40% by volume.
[0013]
Preferably, the temperature of the heat transfer medium is 120 to 300 ° C., and the tobacco moisture of the pressure-treated tobacco is 8 to 25% by weight before the heat treatment. Furthermore, it is advantageous that the tobacco moisture is 8 to 15% by weight after the heat treatment.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
According to a particularly preferred embodiment of the process according to the invention, in the aftertreatment with heat, hot water vapor is supplied in a closed system according to the known principle of flow drying, and the permanent gas is discharged in the discharge zone of the heat-treated tobacco. It is fed downstream of the hot water vapor feed and then circulated in a closed cycle with more water vapor, and after the expanded tobacco has been cooled and discharged, an operation is performed to keep the percentage of permanent gas constant. In particular, this makes it possible to quickly reduce the tobacco temperature and to fix the filling capacity.
[0015]
Hereinafter, a preferred method using a conventional flow dryer will be described with reference to the schematic diagram reproduced in FIG. In this method, air was used as a permanent gas and the proportion was determined indirectly through oxygen measurement.
[0016]
Due to the local pressure difference between the heat transfer medium guided in the cycle and the surroundings, the outside air is sucked into the region of the inlet (1) and the outlet (2), and the steam is discharged through the steam flap (3). The superheated steam is fed through the steam valve (4). The oxygen content of the heat transfer medium was measured with a probe (5). By controlling not only the steam flap (3) but also the steam valve (4), the desired oxygen content and thus a constant ratio of permanent gas to superheated steam can be established.
[0017]
For the following embodiments, the relationship between the filling capacity and the proportion of permanent gas in the heat transfer medium is demonstrated. The proportion of permanent gas required in each case to achieve the optimum filling capacity depends on the type and moisture of the tobacco material used and also on the equipment boundary conditions.
[0018]
EXAMPLE Tobacco treated with an INCOM flow dryer as shown in FIG. 1 was post-treated with heat as follows. The mass flow rate of the introduced tobacco was 1,250 kg / hour, and the volume flow rate of the heat transfer circulating medium composed of superheated steam and air was 7,315 m ³ / hour. The proportion of water vapor and permanent gas that can be estimated through the measurement of oxygen content changed. In this case, the performance of the heater is kept constant according to the scale 1.3, 7.5 and 15% by volume of the oxygen content according to the percentage of permanent gas 6.5 or 37 or 75% by volume, before the introduction of tobacco. In contrast, the initial temperature measured is changed in the range of 185 to 165 ° C.
[0019]
The filling capacity of the discharged and conditioned tobacco was determined from a specific volume converted to ml / g at a nominal moisture of 12% by weight and a nominal temperature of 22 ° C. using a Borgwaldt density meter. The relative filling capacity improvement rate was calculated as follows from a basic experiment using no permanent gas and data of an expanded sample using a heat transfer medium composed of water vapor and permanent gas:
_{(% = (F E -F B} ) (100% / F B
(F _B = filling capacity, basic experiment, water vapor without permanent gas, F _E = filling capacity, expansion, water vapor with permanent gas)
[0020]
The diagram shows the relationship between the filling capacity of the expanded tobacco and the process variable of the oxygen content in the heat transfer medium, and the possibility of setting optimal working conditions with the help of this process variable.
[Brief description of the drawings]
FIG. 1 is an explanatory view conceptually showing a heat treatment method for tobacco impregnated with oxygen and / or argon.
FIG. 2 is a characteristic diagram showing the relationship between the relative filling capacity of the INCOM heat-treated tobacco in the flow dryer and the oxygen content of the heating medium.
[Explanation of symbols]
1 Inlet 2 Outlet 3 Steam flap 4 Steam 5 Probe

Claims (8)

Tobacco material with an initial moisture content of up to about 30% by weight is compressed continuously or stepwise with a treatment gas consisting of nitrogen and / or argon at a pressure of 50 to 1,000 bar and then continuously or stepwise reduced. The compression and decompression steps are carried out in one autoclave or in several autoclaves in a cascaded manner, and then the post-treatment of the discharged tobacco material with heat. A method for improving the filling capacity of tobacco, such as shredded tobacco leaves or veins,
The heat treatment is a fluid heat transfer medium comprising a mixture of permanent gas and superheated steam, and the ratio of the permanent gas is maintained at a constant value in the range of 10 to 60% by volume. A method characterized by being performed by a medium. 2. Method according to claim 1, characterized in that essentially air is used as a permanent gas and the proportion of air is controlled by measuring the oxygen content. 3. A method according to claim 2, wherein the proportion of air in the fluid heat transfer medium is 20-50% by volume. The method according to claim 2, wherein the air ratio of the fluid heat transfer medium is 20 to 40% by volume. The method according to claim 1, wherein the temperature of the heat transfer medium is 120 to 300 ° C. 6. The method according to claim 1, wherein the tobacco moisture of the pressure-treated tobacco is 8 to 25% by weight before the heat treatment. 7. The method according to claim 1, wherein after the heat treatment, the tobacco water content is 8 to 15% by weight. During hot aftertreatment, when hot steam is supplied in a closed system according to the principle of flow drying, the permanent gas is sent downstream of the hot steam feed in the heat treated tobacco discharge zone, and then more in the closed cycle. 8. A method as claimed in claim 1, characterized in that the percentage of permanent gas is controlled to be constant after cooling and discharging of the expanded tobacco while being circulated with a lot of water vapor.

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