EP0074059A2 - Method of improving the filling capacity of tobacco material - Google Patents

Abstract

Filling capacity increases of 30 to 100% are achieved by using tobacco material with a moisture content of 18 to 80% by weight (wet basis) and a temperature of -80 ° to 100 ° C at a speed of at least 20 m / s accelerated, then delayed and dried in the usual way. The tobacco material can be accelerated together with the gaseous medium in a venturi-type nozzle or can be introduced into the rapidly flowing gaseous medium.

Description

The invention relates to a method for improving the fillability of tobacco material by expanding the moist tobacco material by reducing the pressure and then drying to processing moisture.

Numerous methods of the aforementioned type have become known, in which tobacco cut or

Subject tobacco leaf material in a moist state to a more or less violent temperature increase or pressure reduction. The rapid evaporation of the liquid contained in the tobacco, e.g. Water or organic solvents leads to a more or less strong expansion of the tobacco cell structure. The disadvantage of the aforementioned methods is that the expansion ratio is in part unsatisfactory and the expanded structure is at least partially lost in the subsequent processing.

The invention is directed to a method of the type mentioned in the introduction, in which tobacco material in the moist state is subjected to a pressure reduction with a simultaneous strong temperature increase within an extremely short period of time. The sudden evaporation of the liquid contained, in particular water and / or other easily evaporable harmless organic solvents, leads to an improvement in the filling capacity of the tobacco material by 30 to 100%, without the tobacco cell structure being appreciably destroyed. The structure remains intact even after further processing of the tobacco material despite the high expansion result.

Tobacco material in the sense of the invention is to be understood in particular as cut rib and / or leaf material, and also reconstituted tobacco.

The above object is achieved in that the tobacco material with a moisture content of 18 to 80, in particular 30 to 80% (wet basis) and a temperature of -80 to 100 ° C by means of a gaseous medium to a speed of at least 20 m / s accelerated, then slowed down and dried in the usual way.

The method of the invention has the particular advantage that the expansion system can have a simple construction. In view of the low mass ratio of transport gas / tobacco material, the energy requirement is low. Furthermore, the tobacco expansion can be carried out in a continuous procedure with the method of the invention.

Following expansion, the tobacco material is dried to processing moisture in the usual way. Drying is normally carried out to a moisture content of 10 to 16% (wet basis). However, it is also possible to dry the tobacco material to a considerably lower moisture content, for example up to 2% (wet basis). A particularly permanent fixation of the ex panded structure achieved. However, it is necessary to moisten the strongly dried tobacco material thus obtained to a moisture content of 10 to 16% (wet basis) before further processing.

Air, water vapor, air / water vapor mixtures with a water vapor content of 2 to 80% by weight of inert gases, e.g. B. nitrogen or carbon dioxide, hydrocarbon or mixtures; the same are used. Water vapor is preferred, which, depending on the process control, can also be overheated.

According to a preferred embodiment of the invention, the tobacco material is brought into a free jet formed by the gaseous medium and having a flow velocity of at least 20 m / s, the tobacco material either being sucked in by the free jet itself or at the essentially narrowest point of a suitable nozzle, e.g. of a jet pump or similar type. The free jet can also be limited by a fixed wall. Due to the suction effect of the generally turbulent free jet or nozzle, the tobacco material is in the core of the free jet or

Pulled nozzle and accelerated to the flow rate of the gaseous medium. The. in the core of the free jet or the lower pressure prevailing at the same time causes the tobacco material to expand while exchanging heat and material. As the diameter of the free jet or nozzle increases, the flow velocity of the gaseous medium decreases and, correspondingly, the velocity. of the tobacco material, whereby it is e.g. with horizontal arrangement of the free jet or the nozzle comes to separate gaseous medium and tobacco material. The tobacco material is then dried in the usual way. However, the expansion device can also be combined into a unit with a dryer.

The specified flow velocity of the gaseous medium of at least 20 m / s essentially relates to the jet base; it is preferably at least 80 m / s.

So far, such method variants of the invention have been addressed, in which. If the tobacco material is introduced into the gaseous medium which already has a flow velocity of at least 20 m / s and is thus accelerated to the flow velocity of the medium, it is also possible to accelerate the tobacco material, in particular tobacco rib cut, together with the gaseous medium. Preferably, the tobacco material is first brought to a speed of 6 to 50 m / s together with the gaseous medium, accelerated to a speed of at least 50 m / s within a maximum of 1/10 s in an acceleration zone of an expansion reactor, through a zone of constant speed transported and then braked in a deceleration zone of the expansion reactor, the dwell time of the tobacco material in the zone of constant speed being between 1/100 and 1/1000 s. The ratio of the speed of the gaseous medium or the tobacco material in front of the acceleration zone to the maximum speed in the same is at least 1: 3, preferably at least 1: 6. The acceleration of the gaseous medium or the tobacco material is preferably carried out in a venturi-type nozzle arranged in the expansion reactor or in another suitable nozzle arrangement.

In general, it applies to all process variants that the greater the speed and temperature of the gaseous medium, the better the expansion result achieved.

According to a further advantageous embodiment of the invention, the gaseous medium has a temperature of 50 to 1000 ° C, in particular at least 100 ° C. In general, since the temperature of the gaseous medium is above that of the tobacco material, a certain heat exchange takes place, which, however, due to the relative short period in which the tobacco material and the transport gas in ^- can be neglected come contact with respect to the drying.

Although the arrangement of a venturi nozzle at the end of a drying section for tobacco material is known from DE-OS 26 37 124, in particular FIG. ₃ , tobacco expansion cannot occur here either, since the venturi nozzle mentioned is located at one point the device is arranged where there is already dried tobacco; the tobacco dried in this way no longer has the elasticity required for expansion. In contrast, in the method of the invention, the tobacco traverses the expansion path in a moist state and is only then dried.

• Fig. 1 ein Fließschema für eine bevorzugte Verfahrensform;
• Fig. 2 eine Düsenanordnung in schematischer Darstellung zur Verwendung in dem Verfahren gemäß Fig. 1;
• Fig. 3 ein Fließschema für eine andere Ausführungsform des Verfahrens der Erfindung;
• Fig. 4 eine Expansionssektion zur Verwendung in dem Verfahren gemäß Fig. 3;
• Fig. 5 eine unabhängig vom Trockner arbeitende Expansionssektion.

The method of the invention is explained in more detail below with reference to the drawings and exemplary embodiments. Show it:

• Figure 1 is a flow diagram for a preferred process form.
• FIG. 2 shows a nozzle arrangement in a schematic representation for use in the method according to FIG. 1;
• 3 is a flow diagram for another embodiment of the method of the invention;
• Figure 4 shows an expansion section for use in the method of Figure 3;
• 5 shows an expansion section working independently of the dryer.

1, an apparatus for carrying out the method of the invention comprises a conveyor 1 for introducing tobacco rib cut 2 into the feed part of an (horizontally or vertically arranged) expansion reactor 3. The expansion reactor comprises a venturi-type nozzle or another suitable nozzle arrangement with an acceleration zone 4, a zone 5 of constant speed and a deceleration zone 6. A conventional current dryer 7 with a connected separator 8 is connected to the expansion reactor. The system can be self-contained; the seal to the environment is carried out on the feed side by a rotary valve (not shown) and on the take-off side by a rotary valve 9 through which the expan dated tobacco is removed from the system.

The transport gas is supplied via valves or flaps 10 and 11, e.g. Saturated steam at 10 and fresh air at 11; the exhaust gas is removed via a flap 12.

• Tabakmaterial mit einem Feuchtegehalt von 18 bis 80,insbesondere 30 bis 80, vorzugsweise 40 bis 80% (Naßbasis)wird bei Temperaturen zwischen -80⁰C und +100°C zusammen mit einem Heißgasstrom durch die Expansionsdüse gefördert. Der Heißgasstrom weist Temperaturen zwischen 50 und 1000 C auf; sein Dampfgehalt kann zwischen 0 und 100 Gew.% betragen. Die Heißgasstromgeschwindigkeit vor der Beschleunigungszone liegt zwischen 6 und 50 m/s: sie steigt im engsten Düsenquerschnitt auf mindestens 50 m/s. Der Heißgasmassenstrom ist 5 bis 36mal größer als der Tabakmassenstrom. Die plötzliche Druckabsenkung in der Düse führt zur sogenannten Flashverdampfung aus der Einzelfaser heraus. Der extrem schnell entstehende Dampf bläht die Fasern auf. Die Energie zur Verdampfung des Wassers wird im wesentlichen aus der Tabakfaser selbst bezogen, d.h. die Temperatur des Tabakmaterials sinkt in der Expansionsdüse nur geringfügig. Der Expansionsvorgang dauert weniger als 0, s, insbesondere 1/100 bis 1/1000 s.

The nozzle arrangement (4, 5, 6) can also be seen in an enlarged view from FIG. 2. The following general process parameters apply to the process of the invention:

• Tobacco material having a moisture content of 18 to 80, in particular 30 to 80, preferably 40 to 80% (wet basis) is conveyed at temperatures between -80 ⁰ C and + 100 ° C together with a hot gas flow through the expansion nozzle. The hot gas flow has temperatures between 50 and 1000 C; its steam content can be between 0 and 100% by weight. The hot gas flow speed in front of the acceleration zone is between 6 and 50 m / s: it increases in the narrowest nozzle cross-section to at least 50 m / s. The hot gas mass flow is 5 to 36 times larger than the tobacco mass flow. The sudden drop in pressure in the nozzle leads to so-called flash evaporation from the single fiber. The extremely quickly generated steam inflates the fibers. The energy for the evaporation of the water is essentially obtained from the tobacco fiber itself, ie the temperature of the tobacco material drops only slightly in the expansion nozzle. The expansion process takes less than 0.1 s, in particular 1/100 to 1/1000 s.

The apparatus for carrying out the method of the invention according to FIG. 3 comprises, in addition to the conveying device 1 for the tobacco material 2, a feed part 13 which is horizontal arranged expansion section 14, which consists of a tube 15 and longitudinal slots 16 in the manner shown in FIG. 4. The longitudinal slots form the base points for a free jet 17. In the embodiment shown here, the expansion device 15 is integrated in the inlet of a conventional current dryer 18, so that the free jet 17 conveys the tobacco material 2 directly into the current dryer 18. Baffles provided to improve the flow guidance are not shown. The tobacco material is withdrawn from the current dryer via the separator 8 and the rotary valve 9.

The system can be self-contained, the sealing to the environment takes place on the feed side by a rotary valve (not shown) and on the take-off side by rotary valve 9, through which the expanded material is removed from the system.

The gaseous medium is supplied via a valve 19; the valve 10 and the flaps 11 and 12 are used to adjust the dryer.

5 shows an expansion device decoupled from drying. The tobacco material entering the system via a cellular wheel sluice 20 hits the jet 17 essentially perpendicularly, is accelerated and expanded by the jet 17, and is guided away essentially horizontally to a dryer device (not shown) of any configuration. Depending on the design of the expansion device, there may be overpressure or underpressure in the system.

• Tabakmaterial mit einem Feuchtegehalt von 18 bis 80, insbesondere 30 bis 80 % (Naßbasis) wird bei Temperaturen zwischen -80° und 100 C in den Fußpunkt des Freistrahls bzw. einer Düse gefördert, vom gasförmigen Medium beschleunigt und anschließend abgebremst sowie in einen Trockner geleitet. Das Treibgas weist Temperaturen zwischen 50 und 1000°C auf; sein Dampfgehalt kann zwischen 0 und 100 Gew.-% betragen. Die Treibgasgeschwindigkeit im engsten Querschnitt der Düse bzw. am Fußpunkt des Freistrahls beträgt mindestns 20 m/s. Eine Obergrenze der Strömungsgeschwindigkeit ergibt sich allein aus praktischen Gesichtspunkten, sie kann z.B. bis zu 900 m/s betragen. Die plötzliche Druckabsenkung im Freistrahl bzw. in der Düse mit überlagerter Wärmezufuhr führt zur sogenannten Flashverdampfung aus der Einzelfaser heraus. Der Expansionsvorgang dauert weniger als 0,5 s, insbesondere 1/10 bis 1/1000 s.

The following general process parameters apply to the method of the invention according to FIG. 3:

• Tobacco material with a moisture content of 18 to 80, especially 30 to 80% (wet basis) is conveyed to the base of the free jet or a nozzle at temperatures between -80 ° and 100 ° C, accelerated by the gaseous medium and then decelerated and passed to a dryer . The propellant gas has temperatures between 50 and 1000 ° C; its steam content can be between 0 and 100% by weight. The propellant gas velocity in the narrowest cross-section of the nozzle or at the base of the free jet is at least 20 m / s. An upper limit of the flow velocity results solely from a practical point of view, for example up to 900 m / s. The sudden drop in pressure in the free jet or in the nozzle with superimposed heat supply leads to so-called flash evaporation from the single fiber. The expansion process takes less than 0.5 s, in particular 1/10 to 1/1000 s.

The invention is explained in more detail below on the basis of exemplary embodiments.

example 1

A pilot plant on a pilot plant scale was used to investigate the method of the invention according to FIG. 1. The dimensions of the pilot plant are as follows:

For the test, the pilot plant was set up in such a way that the rib cut could be entered without a lock. The rib cut to be treated was moistened with cold water to approx. 45% (wet basis) and conveyed into the entry at ambient temperature (25 ° C.). The mass flow of the rib cut was 25 kg / h, the transport gas mass flow was 300 kg / h. The ratio of transport gas to rib cut mass flow is thus 12: 1. The temperature of the transport gas flow at the rib cut entry was 340 ° C.

A transport gas mass flow with a steam content of 85 mass percent was set. A speed of 22 m / s was measured in the cross section immediately behind the tobacco inlet and a speed of 137.5 m / s in the narrowest cross section of the expansion nozzle. Behind the relaxation nozzle, the rib cut was practiced in the rest drying section to 13%. The discharge was done by a cyclone. The expanded ribs section and a treated for comparison purposes only in a flow drier ribs sectional were conditioned for 72 hours at 60% relative humidity and 22 ⁰ C (according to DIN 10244) The Füllkraftmessung made in Borgwaldt Densimeter (initial weight 10 g, diameter mm of the measuring cup 60, load 3000 g and 30 s).

The remaining height of the rib cut treated according to the prior art was 14.8 mm; that of the one obtained by the process of the invention was 23.7 mm, in each case at a humidity of 12.6%; determined according to the oven method: 3 h, 80 ° C.

The increase in the filling capacity of the tobacco rib cut treated according to the method of the invention is approximately 60% compared to the comparison product according to this measurement method.

Example 2

The experiment according to Example 1 was repeated with a leaf cut (20% moisture; wet basis). Because of the lower initial moisture, the tobacco mass flow was increased to 80 kg / h and the dryer temperature was reduced to 250 ° C. A filling capacity increase of 30% was obtained.

Example 3

The experiment according to Example 1 was repeated in the pilot plant described there, the steam content of the transport gas mass flow being reduced to 4% by mass. The rib cut to be treated was approx. 45% with cold water (Wet basis) moistened and conveyed at ambient temperature (25 ⁰ C) in the entry. The mass flow of the rib cut was 25 kg / h; that of the transport gas 300 kg / h. This results in a ratio of transport gas to rib cut mass flow of 12: 1. The temperature of the transport gas mass flow at the rib cut entry was 340 ° C.

Due to the change in density, there is a speed of 15 m / s immediately behind the tobacco inlet and a speed in the narrowest cross section of the expansion nozzle of 93.8 m / s. Behind the expansion nozzle, the rib cut was dried to 13% in a normal drying section. A cyclone removes them. The conditioning and measurement was carried out analogously to Example 1. According to the measurement method used, the increase in the filling capacity for the tobacco rib cut treated according to the invention is 30

Example 4

A semi-technical system was used to examine the method of the invention according to FIG. 3. The dimensions of the system are as follows:

The experiments given here were carried out with a rib cut. For the test, the pilot plant was set up in such a way that the rib cut could be entered without a lock. The rib section to be treated was moistened with cold water to approx. 45% (wet basis) and at ambient temperature (20 ° C) promoted in the entry. The mass flow of the rib cut was 100 kg / h. As a propellant gas saturated steam at 8 bar was (t = ⁰ 170.41 C). The motive steam flow was 300 kg / h. The ratio of the rib cut to the motive steam mass flow is thus 1: 3. Behind the free jet, the rib cut was dried in the usual drying section with air at a temperature of 340 ° C. to 15%. The discharge was carried out by a cyclone. The expanded rib cut and a rib cut treated for comparison purposes in a current dryer (without free jet) were conditioned for 72 hours at 60% relative air humidity and 22 ° C (according to DIN 10244). The filling force was measured in the Borgwaldt densimeter (sample weight 10 g, diameter of the measuring cup 60 mm, load 3000 g and 30 s).

The residual height of the rib cut treated according to the prior art was 14.8 mm, that of the one obtained by the method of the invention was 18.59 mm, in each case at a humidity of 12.6%, determined by the oven method: 3 h, 80 ° C. The increase in the filling capacity of the tobacco rib cut treated according to the method of the invention is approximately 25 compared to the comparison product according to this measurement method

Example 5

The experiment according to Example 4 was repeated in the pilot plant described there, the motive steam mass flow being reduced to 80 kg / h and overheating to 300 ° G (a larger motive steam mass flow could not be run because of the steam superheater available). The rib cut to be treated was moistened with cold water to approx. 45% (wet basis) and conveyed to the base point of the free jet at ambient temperature (25 ° C.). The mass flow of the rib cut

was 100 kg / h. The ratio of the rib cut to the motive steam mass flow is therefore 1: 0.8. The rib cut was dried behind the free jet in the drying section at a temperature of 340 ° C. to 15%.

The discharge was carried out by a cyclone. The conditioning and measurement was carried out analogously to Example 3. According to the measurement method used, the increase in the filling capacity for the tobacco rib cut treated according to the invention is 30%.

Claims (10)

1. A method for improving the fillability of tobacco 'material by expansion of the moist tobacco material by reducing the pressure and subsequent drying to processing moisture, characterized in that the tobacco material (2) with a moisture content of 18 to 80 wt .-% (wet basis) and one Temperature from -80 ° to 100 ° C accelerated by means of a gaseous medium to a speed of at least 20 m / s, then decelerated and dried in the usual way. 2. The method according to claim 1, characterized in that the tobacco material (2) is brought into a free jet (17) formed by the gaseous medium and having a flow velocity of at least 20 m / s. 3. The method according to claim 1 or 2, characterized in that the tobacco material (2) is sucked through the free jet (17). 4. The method according to claim 1 or 2, characterized in that the tobacco material is introduced at the substantially narrowest point of a nozzle of the jet pump type. 5. The method according to claim 1, characterized in that the tobacco material is accelerated together with the gaseous medium. 6. The method according to claim 5, characterized in that the tobacco material (2) brought together with the gaseous medium to a speed of 6 to 50 m / s, in an acceleration zone (4) of an expansion reactor within a maximum of 1/10 s to Accelerated speed of at least 50 m / s, transported through a zone (5) of constant speed and then decelerated in a deceleration zone (6) of the expansion reactor, in particular to the initial speed, the dwell time of the tobacco material in the zone of constant speed (5) is between 1/100 and 1/1000 s. 7. The method according to claim 5 or 6, characterized in that the ratio of the speed of the gaseous medium or tobacco material in front of the acceleration zone (4) to the maximum speed in the same is at least 1: 3, preferably at least 1: 6. 8. The method according to any one of claims 5 to 7, characterized in that the acceleration of the gaseous Medium or the tobacco material takes place in a venturi-type nozzle arranged in the expansion reactor. 9. The method according to any one of claims 1 to 8, characterized in that the gaseous medium has a temperature of 50 to 1000 ° C. 10. The method according to any one of claims 1 to 9, characterized in that the gaseous medium is air, water vapor, inert gas, hydrocarbons or a mixture thereof.

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