IL31884A - Process for increasing filling capacity of tobacco - Google Patents

Description

PROCESS FOR INCREASING FILLING CAPACITY OF TOBACCO pao ® n ia'pn iwia n^iAn T» nn This invention relates to a process for treating tobacco to increase its filling capacity.

Tobacco leaves, when harvested, contain a considerable quantity of water and during the tobacco curing process this water is removed by drying resulting in shrinkage of the leaf structure. In the usual process of preparing tobacco for storage and subsequent cigar and cigarette manufacture, the tobacco regains very little, if any, of the shrinkage resulting from drying so that a significant loss in the filling capa-city of the tobacco is the result. Thus, the tobacco has a bulk density which is in excess of that necessarily required for making satisfactory cigars or cigarettes.

Several procedures have been suggested in the prior art for increasing the normal filling capacity of dried" or cured tobacco. Certain of these processes involve puffing operations in which tobacco is subjected to high pressure steam followed by sudden release of the pressure. Also, it has been suggested that the filling capacity of tobacco may be increased i.e., bulk density reduced, by exposing the tobacco particles to the vapors of an organic liquid or to an organic liquid followed by air drying at ordinary temperatures. However, these prior procedures have not been wholly satisfactory because (a) they are not effective for expanding the filling capacity to any great extent or (b) they result in a shattering of the to-bacco particles so that considerable waste incident to the formation of fines results.

The present invention provides a process for increasing the filling capacity of tobacco which comprises contacting tobacco with a sufficient quantity of a volatile organic liquid to thoroughly impregnate same and thereafter passing a gas into contact with said tobacco, said gas being heated to a temperature of at least 30°F. above the boiling point of said liquid at the contacting pressure, whereby said tobacco is expanded and said liquid is separated therefrom in the vapor state.

The process of this invention can be applied to cured tobacco in the form of leaf (including veins and stems), strips (leaf with stems removed) or cut filler (straps shredded for cigarette making). By Using leaf or strips, the types or grades of tobacco can be selected for which the process is most effective, thereby achieving results near the maximum while holding processing costs to a minimum, if the entire blend is to be treated, then cut filler is preferably utilized.

One of the preferred aspects of the invention is to use a moist cured tobacco.

A variety of organic liquids that can be evaporative-ly removed can be used for impregnation but preferably the organic liquid is one having a boiling point below that of water. It is thought that in addition to helping to expand tobacco structure the inert organic liquid helps to set the cells in expanded condition. The organic liquid should not be one which does combine irreversably to a significant degree with the tobacco; in other words it must not alter the smoking qual-ities of the product to an undesirable extent, _1. . , It should be inert. Broadly the liquid falls into the classes of aliphatic hydrocarbons, aromatic hydrocarbons, alkanols, ketones, aliphatic esters, ethers, halogen substituted hydrocarbons and .... . -2- . . ... .. mixtures thereof . It is preferred to operate with the lower boiling members of these classes . It is intended that "lower boiling" include those liquids having a boiling point below about 231°F . (110.7°C. ) and preferably below about 155°P . (68.5e C. ) .

Illustrative suitable inert organic liquids are : benzene and toluene; acetone, methyl et hyl ketone, methyl iso- propyl ketone , diethyl ketone and diacetyl ketone ; methyl ethyl ether, diethyl ether, dipropyl ether, diisopropyl ether, methyl butyl ether, ethyl butyl ether, ethylene glycol dimethyl ether, and tetrahyd ofuran; methanol, ethanol, propanol, isopropanol, sec -butyl alcohol, t -butyl alcohol, t -amyl alcohol, and allyl alcohol; butane , pentane, hexane, heptane , and the corresponding unsaturated hydrocarbons ; and cyclobutane, cyclopentane, cyclohexane and cyclohexene .

The halogen substituted hydrocarbons may be aliphat^ ; ic, cycloaliphatic or aromatic in nature . One or more halogen atoms may be present in each halohydrocarbon molecule . Two or more different halogens may be present in a single halohydro- carbon molecule . Illus trative halohydrocarbons are ethyl chloride, propyl chloride, isopropyl chloride, vinylidene chloride, n-butyl bromide, isobutyl chloride, sec-butyl chloride, t -butyl chloride , t -butyl bromide, methylene chloride, methylene bromide, chloroform, carbon tetrachloride, ethylene dichloride, , ethylidene chloride, acetylene dichloride, trichloroethylene and luorobenzene .

Preferred classes of inert organic liquids are aliphatic hydrocarbons having 3 to 6 carbon atoms and the halogen substituted alkane hydrocarbons (halo-alkane) having 1-2 carbon atoms and the halocycloalkanes having 3-4 carbon atoms. Those compounds generally known as Freon fluorocarbons are especially preferred. Illustrative of the preferred Freon liquids are trichloromonofluoromethane, dichlorodlfluoro-methane, monobromotrifluoromethane, monochlorodifluoromethane, trichlorotrifluoroethane, dichlorotetrafluoroethane, octa-fluorocyclobutane and tetrachlorodifluoroethane .

The amount of impregnating inert organic liquid is controlled for optimum results; broadly speaking it is between 15 parts by weight of liquid per 100 parts by weight of tobacco and about the maximum impregnation amount of liquid.

The maximum impregnation amount is the maximum amount which can be taken up by the tobacco. In general the amount of lm-pregnating liquid used is between about 25 to 350 parts by weight per 100 parts by weight of tobacco. There is a tendency to impart mechanical difficulties in the handling of the tobacco impregnated with the higher amounts of liquid.

When operating with the preferred organic liquids it is preferred to use between about 40 to 250 parts by weight per 100 parts by weight of tobacco.

The temperature and pressure conditions under which the tobacco is contacted with the organic liquid are not critical, and generally speaking, ordinary room temperatures and pressures are entirely satisfactory. No special equipment is required for impregnating the tobacco with the inert organic liquid and impregnation can be carried out in any suitable type of tank, drum or other container. However, in the case of liquids having a low boiling point or high vapor pressure, the impregnation should be carried out at redu ced temperatures or elevated pressures so that the liquid does not vaporize during the equilibration step. Preferably it is carried out at a tem perature below about 170°F. in order to avoid impairing the flavor of the tobacco , i After the tobacco has been impregnated with the organic liquid, it is preferred that the tobacco be allowed to equilibrate, i.e . , remain in contact, with the liquid for a period of time . Here again this time will depend upon the physical state of the tobacco and the particular liquid that may be selected for impregnation. In the case of leaf, stems or strips, the contact time may be longer than for the treatment of more finely divided tobacco particles such as cut filler. Periods from a few minutes to as long as 24 hours are satisfactory . Also the time needed to impregnate substantially uniformly the mass of tobacco is temperature dependent; also the time of impregnation is dependent upon the particle size of the tobacco. The larger the particle size the longer the time . The illustrative times for moist strips and shreds are : 150°F. , 0.5 to 1 hour; 100 °F. , 12-24 hours; 75°F. , 40-100 hours.

After the tobacco has been thoroughly impregnated with the organic liquid the organic liquid is rapidly removed therefrom. This is accomplished by passing a hot gas thro ugh the impregnated tobacco to rapidly remove the organic liquid in a short period, such as on the order of a few seconds, as for example less than about 4 seconds . In order to obtain the desired volume increase of tobacco and avoid impairing flavor quality, it is particularly advantageous to remove the organic impregnating liquid rapidly. Use of a hot gas at a temperature of between 250 and 400°F. effectively removes... the > impregnating liquid very rapidly so as to cause expansion of the tobacco structure while avoiding shatterin the tobacco into dust or fines. When processing cigarette cut filler, the expansion of the structure also causes delamination of laminated shreds which serves to increase the filling capacity and also improves the burning qualities of the filler. The organic liquid removal is preferably carried out at substantially, atmospheric pressure but it can be carried out at super atmospheric pressures when using very low boiling liquid. The gas is employed at a temperature of at least about 30°F. and preferably at least 200°F. higher than the boiling point of the organic liquid employed for impregnation. The temperature of the gas thus depends on the boiling point of the organic impregnating liquid. It is preferred to avoid use of gas temperatures higher than about 400°F. so as to avoid flavor impairment of the tobacco compo-sitlon. The gas is preferably maintained at a temperature below about 350°F. The hot gas is preferably steam or a mixture of vaporized organic liquid and steam, but other hot gases such as, for example, air, nitrogen, carbon dioxide, gaseous organic liquid or mixtures thereof or any other gas which is inert with respect to the tobacco and the volatile organic impregnating liquid can be advantageously employed.

After evaporative removal of the organic impregnating liquid from the tobacco the organic liquid can be recovered, condensed and recycled for further use . The expanded tobacco is then reordered to the water content des ired for the particular end use . By reordering it is meant that the moisture content of the expanded tobacco is adjusted to a desired value such as, for example, 12-13 for cut filler for cigarette making . In accordance with one embodiment of this invention, a moist, -cure^d tobacco having a water content in the range of about 10 to 100 parts by weight of water per 100 parts by weight of tobacco is employed prior to the organic liquid lm- pregnation. Preferably, the water content of the tobacco is within the range of 13 to 50 parts per 100 parts of tobacco and most preferably within the range of 18 to 30 parts per 100 parts of tobacco . The term "100 parts of tobacco " means tobacco on a water-free basis . To illustrate, a cured tobacco having a natural water content of 12.3$ is described herein as having about 14.1 parts of water per 100 parts of tobacco . The lower moisture, limit of the tobacco to be treated is for the main imposed by the fragility of the tobacco; tobacco which is too dry tends to disintegrate and to produce fines . The amount of water employed can be large enough to permit the tobacco to be soaking wet; however, the use of water in amounts such that the tobacco is very wet is preferably avoided because of mechanical difficulties in handling such wet masses of tobacco . The upper limit of 100 parts of moisture per 100 parts of tobacco is a practical preferred operating limit . The moistening operation can be carried out at ambient temperatures and also at elevated temperatures . It is usually preferred to maintain t he tobacco below about 170°F . in order to avoid impairing flavor. In general, the moistening is carried out at ambient atmospheric temperatures such as 60°F. to 100°F. The water can be added to the tobacco by any technique which results in a substantially uniform moistened mass, such as by spraying or soaking.

When the moisture content of the tobacco is within the desired range, the tobacco is then contacted with sufficient quantity of a volatile organic liquid for a time suffi-c lent to accomplish thorough impregnation of the tobacco.

The process of the invention is further described with reference to the drawing, the single figure of which illustrates in block diagrammatic form an embodiment of the process of the invention.

Tobacco moistener 1 is a unit adapted for adding water from line 2 to cured tobacco feed from line 3. Moistener 1 may add the water by means of spraying, or passage through a pool of water with provisions made for draining off excess water and for a period of time during which the water diffuses throughout the mass of tobacco. In order to maintain the water soluble components in the tobacco, any water which is drained from the moist tobacco is recycled by way of line 2, thus preventing net extraction of soluble material from the tobacco. In some instances the tobacco may already have a moisture content equal to the desired water content of the moist tobacco. In this case moistener 1 would be bypassed (by way of line 3A) .

The moist tobacco is. passed by way of conveyor line 4 to impregnator 6 which can, for example, be a closed cylln- der provided with a screw for moving the moist tobacco therethrough. Here the moist tobacco is impregnated with organic liquid from line 7. The organic liquid can be added in much the same manner as is the water in moistener 1. Also, any drained liquid from impregnator 6 is recycled (via line 7A) to line 7 in order to reduce losses of liquid soluble components from the tobacco. Impregnator 6 is adapted to operate at moderately elevated temperatures such as l40pF. j usually at autogenous pressure . Imposed pressures can be used to help maintain the organic liquid in the liquid state and to ln>-crease the impregnation rate . Illustratively, 700 pounds of cut filler tobacco, 180 pounds of water and 1200 pounds of Freon 11 can be introduced into impregnator 6 with the tobacco remaining in the impregnator for approximately 30 minutes .

The moist, impregnated tobacco is then passed by way of line 8 to line 9 for introduction into tobacco expander 13. A gaseous mixture such as Freon and steam is passed from gas heater 11 by way of line 9 into expander 13 where the hot gas and the moist impregnated tobacco are thoroughly intermingled . A sufficien flow of gas is used to effect evaporative removal of the impregnated liquid from the tobacco at a rapid rate . Fan 12 is employed for flowing the hot gas through expander 13 , Illustratively, when expanding 700 pounds of moist, impregnated tobacco per hour a gaseous mixture of 280, 000 pounds of Fre,on 11 and 38, 700 pounds of steam per hour are Introduced into expander 13 at a temperature of about 340°F. and a linear velocity of approximately 27 feet per second . With an expander unit of 84 feet in height, the moist impregnated tobacco is contacted with the hot gas for approximately 3.1 seconds.

In expander unit 13 the tobacco Is expanded (Increased In filling capacity) with the hot gas carrying the expanded tobacco into separator 14. Separator 14 can be any con-ventional form of separator such as a cyclone type. The expanded tobacco product is withdrawn from separator 14 by way of line 16 and passed, if desired, for processing economy, into a residual liquid removal operation in unit 17. Conveniently the expanded tobacco Is contacted with steam introduced through line 18 in an amount sufficient to vaporize all of the residual organic liquid. The condensed steam from residual re« moval operation 17 is passed by way of line 19 to a recovery operation for recovery of the organic liquid content.

Normally, the organic liquid-free tobacco from resid-ual liquid removal operation 17 is reordered to a water content suitable for storage or immediate use. If reordering is desired, the liquid-free tobacco is passed to reordering operation 21 where it is brought to the desired moisture content by drying or moistening operations well known to the tobacco in-dustry. The reordered expanded tobacco composition (product) is then passed to storage for subsequent use through line 22.

The heating gas and organic liquid vapor and water vapor removed from the moist impregnated tobacco are recycled from separator 14 via line 28 to gas heater 11, thence to ex-pander 13 via line 9. Excess gases from the recycle circuit are bled by way of line 23 into liquid recovery operation 24. Here the water and liquid are condensed. Water is removed by way of line 26 and organic liquid is recycled to impregnator 6 by way of line 27. Where organic liquid immiscible with water is employed, simple decantation is used for separation. Distillation is used for recovery of organic liquids which are miscible with water.

By the process of this invention it is possible to increase the filling capacity of cured tobacco by as much as 20 to 100 percent or even more. This tobacco product, having decreased bulk density, is particularly useful for the manufacture of smoking products such as cigarettes, cigars. and pipe tobacco. The bulk density having been decreased, considerable savings Jn tobacco cost are obtained in the manufacture of these smoking products without sacrificing quality.

In order to measure the filling capacity of a cut filler tobacco product as described in the following examples, a compressometer is used which is essentially composed of a cylinder 9.5 centimeters in diameter with a graduated scale on the side. A piston 9.4 centimeters in diameter slides in the cylinder. Pressure is applied to the piston and volume in milliliters of a given weight of tobacco, 100 grams, is deter-mined. Experiments have shown that this apparatus will accurately determine the volume (filling capacity) of a given amount of cut tobacco with good reproducibility. The pressure on the tobacco applied by the piston in all examples was 2.30 pounds per square inch applied for five seconds, at which time the volume reading was taken. This pressure corresponds closely to the pressure normally applied by the wrapping paper to tobacco in cigarettes. The moisture content of the tobacco affects the filling capacity values determined by this method, therefore comparative filling capacities were obtained at similar moisture contents .

For a more complete understanding of this invention, reference will now be made to several examples which are illus-trative thereof : Example 1 A cured cut cigarette tobacco containing 12.3$ moisture and having a filling capacity of 58 milliliters when determined by the procedure previously indicated was mixed with a sufficient amount of ethanol (boiling point about 173 to thoroughly Impregnate the tobacco. The alcohol-treated tobacco was equilibrated in a closed container for about 20 hours, after which time a stream of steam having a temperature of 212°F. was passed through the alcohol-treated tobacco for a period of five minutes . After this time the tobacco had expanded and the alcohol had been completely removed by vaporization. The moisture content of the tobacco was then adjusted to 10.9$ by weight . The resulting tobacco was suitable for use in the manufacture of cigarettes and had a filling capacity of 517 milliliters , which represents , an increase of approximately 12. by volume over the orig inal tobacco.

The procedure of Example 1 was repeated using steam and the results are noted in Table I.

TABLE I Percent by Time volume Adjusted subjected Pilling increase moisture to steam capacity in content Exin milli- filling in by ample Organic Liquid minutes liters capacity weight 2 acetone 533 I .7 11.1 (b.p. 13 °P.) 3 ethyl ether 614 34.1 9«7 (b.p. 9 .2°F.) 4 benzene 5 522 14.0 12.0 (b.p. 176°P.) hexane 5 576 25.8 12.1 (b.p. 156 °F.) 6 pentane 2 704 53.7 12.1 (b.p. 95°F.) 7 pentane 1 921 101.0 9.6 8 dichloromethane I.25 605 32.2 10.0 (b.p. 104°P.) 9 Freon-11 2 682 46.8 10.1 trichloromono- fluorome thane (b. . 75°F.) under slight superatmospheric pressure Example 10 Shredded flue -cured tobacco stems (200 grams) were treated with 250 milliliters of pentane and equilibrated overnight in a closed container. The treated tobacco was then exposed to steam at 212 °F. for a period of one minute and dried in air. The moisture content of the resulting tobacco was 13.5^ and its filling capacity was 92I milliliters. A control sample which had not been treated with the pentane had a mois- ture content of 14.0 and a filling capacity of 466 milliliters . Thus, the filling capacity due to the pentane treatment followed by steaming was increased approximately 98.6 , Example 11 The experiment of Example 10 was repeated except that ethyl ether was used as the organic liquid . The moisture content of the final tobacco was 14.0# and the filling capacity was 563 milliliters, representing an increase of approximately 21<¾ over the control.

Example 12 The experiment of Example 10 was repeated using shredded burley tobacco stems with pentane as the organic liquid . The final product had a moisture content of 12.5# and a filling capacity of IO36 milliliters . The control which had not been subjected to pentane had a moisture content of 12.6$ and a filling capacity of 7 3 milliliters . Thus, the pentane -trea ted and steamed sample showed an increase in filling capacity over the control of approximately 39.4#.

Example 13 The process of Example 12 was repeated using shredded burley tobacco stems and ethyl ether as the organic liquid . The final moisture content was 13 .1$ and the filling capacity was 821 milliliters, representing a 10.5$ increase over th e control .

Example 14 A sample (2633 grams ) of flue -cured tobacco strips was equilibrated with 4500 milliliters pentane in a closed container for 20 hours . Small batches (100 grams or less ) of the pentane -treated tobacco were then exposed to steam at 212°F . In a wire mesh basket for five to thirty seconds and then dried in air. The resulting expanded strips were shredded in the conventional manner and the tobacco was fabricated into cigarettes . Control cigarettes were made from untreated strips and the physical characteristics of the cigarettes from the expanded and untreated flue-cured tobac cos are compared in the f ollowing Table II: TABIE II Determination Control Expanded Weight, g . I .036 Ο.769 Draft Resistance, in. 2.10 2.26 Firmness, 0.1 mm. 8.83 9.58 Circumference, mm. 25.33 25.27 Moisture, 12.08 12.20 ^Data based on average of 50 cigarettes (70 mm. ) . 2Cigarettes stored at 63$ humidity for 9 hours .

Example 15 Regular blended cigarette cut filler, 500 grams containing 12.7# moisture (14.5 parts of water per 100 parts of tobacco) , was sprayed with 1125 milliliters of water and bulked one hour. The moist tobacco was dipped in Freon-MF liquid utilizing a total of 8 liters of the liquid (300 parts of Freon-MF per 100 parts of tobacco) . The tobacco was sealed in a pressure vessel, which was then heated 75 minutes by water at 133 °F . ; internal pressure was 30 pounds per square inch, gauge, at the end of the heating period . The vessel was cooled by wate r at 50°F. for 15 minutes, and 2650 milliliters of excess liquid Preon-MP was drained from the vessel affording a net impregnation of 201 parts of Freon-MP per 100 parts of tobacco . The tobacco was then intimately contacted in a vertical column with a hot gas mixture, comprising air, water vapor, and gaseous Freon-MP, at a gas inlet temperature of 330°F. for a contact time of about 2 seconds . Tobacco from the hot gas contacting was reordered with a water spray and bulked overnight (allowed to stand in a closed vessel overnight o equilibrate the moisture) .

# Filling Capacity, Increased Moisture ml/100 g. Filling Capacity Control 12.7 422 Treated product 12.4 596 41 The procedure of Example 15 is carried out for examples 16 to 25 and the results noted l in Table III.

TABLE III Example 16 17 18 19 20 21 22 23 24 25 a a1 a1 a2 a3 a a1 a* a1 a2 a2 b 4500 500 5700 3920 5700 5700 . 5700 , 5700. 5700 5700 c 12.7 12.1 11.3 11.6 11.6 18.75 I8.85 18.1 17.3 17.4 d 0 225 570 392 570 - - - - -e overover1 hr. over1 hr. - - - - - night night night f 26 I9.3 24 24.4 24.4 - - -g 8 8 12 7 11 10 8 8 10 6 h 300 298 ,350 322 318 225 - 313 -i 90 90 90 90 45 60 60 60 60 J 133 133 I3 127 127 149 149 151 147 145 k 31 31 37 26 27 40 39 39 40 33 1 50 50 50 50 50 - 50 50 50 50 50 m 20 40 12 20 12 20 8 11 16 10 n 3I5O 4200 3IOO 27ΟΟ 4 ΟΟ 495Ο 4300 2400 4000 2000 0 182 142 259 - I 0 161 118 - 188 - P 330 341 343 335 339 3 7 347 347 343 344 q 1 0.75 0.7 0.7 0.7 0.7 0.7 0.7 Ο.65 Ο.65 r 20 - 17 7 13 16 13 12.25 12.75 9.75 6 12.7 12.1 11.3 11.6 11.6 12.7 12.1 12.1 11.3 11.3 t 422 43Ο 463 ' 427 415 422 430 30 463 463 U 12.2 11.8 11.6 12.1 12.0 12.5 12.1 12.0 12.0 12.0 V 595 612 731 496 567 613 628 620 725 720 Vf 41 42 58 16 37 46 44 57 a - Type of tobacco used a1 - Regular blended cigarette cut filler a2 *· Flue-cured cut filler - Burley cut filler - Turkish cut filler amount of tobacco in grams by weight of moisture Milliliters of water sprayed Time of water bulking Parts by weight of water per 100 parts of tobacco for water bulking Liters of Freon-MF liquid comprising that drained from a previous run.

Parts by weight of Preon-MP per 100 parts of tobacco Minutes for heating pressure vessel °F. temperature of water used to heat the pressure vessel Internal pressure of vessel in pounds per square inch, gauge °P. temperature of water to cool vessel Minutes for cooling vessel Milliliters of excess liquid Freon-MP drained from the vessel Net impregnation of parts by weight of Freon-MP per 100 parts of tobacco °P. gas inlet temperature pf air, water vapor, and Freon-MP gas Contact time in seconds Period in minutes of uniform tobacco feed rate Percent by weight of moisture in control Filling capacity in ml/100 grams of control Percent by weight moisture in product treated by the Example Filling capacity in ml/100 grams of treated product Percent by volume increase In filling capacity of treated product Example 26 Flue-cured cut filler, 5700 grams containing 17.6# moisture, was placed in a pressure vessel and 8 liters of Freon-MF liquid, comprising that drained from a previous run, was poured over the tobacco, and 2000 milliliters of excess liquid Freon-MF Was drained from the vessel. The vessel was then sealed and heated for one hour by water at 151°F. ; internal pressure was 31 pounds per square inch, gauge, at the end of the heating period. The vessel was then cooled by water at 50°F. for 6 minutes, and 1500 milliliters more excess liquid Freon-MF was drained from the vessel. The tobacco was then intimately contacted by passing it through a vertical column with a flowing hot gas mixture, comprising air, water vapor, and Freon-MF gas, at a gas inlet temperature of 33 °F. for a contact time of tobacco with hot gas of about Ο.65 seconds . The tobacco feed rate was uniform over a period of minutes . Tobacco. from the hot gas contacting was reordered with a water spray and bulked overnight .

# Filling Capacity, Increased Moisture ml/100 g. Filling Capacity Control 11.3 63 Treated Product 12.3 704 52 Example 27 Flue-cured cut filler, 5, 700 grams, was placed in a pressure vessel and 28 liters of a mixture consisting of three parts Freon-MF and one part isopropanol, by volume, was poured over jhe tobacco . The vessel was then seal ed and heated for one hour by hot water (l40°F. ) j internal pressure was 60 pounds per squar e inch, gauge, at the end of the heating period .

Pressure was relieved by draining off the excess liquid with consequent flashing off of vapors; 13.2 liters of the liquid was collected . The vessel was further cooled by tap water and an additional 2.3 liters of excess liquid drained from the ves-sel. The treated tobacco was then intimately contacted with a flowing hot gas mixture, comprising air, water vapor, iao-propanol vapor, and Freon-MF gas . Tobacco from the hot gas contacting was reordered with a water spray and bulked overnight .

Pilling Capacity Increased Moisture ml/100 g. Pilling Capacity Control - 387 Treated product 12.8 (In- 65 69 eluding alcohol) Freon-MF employed in the specific examples hereof is trichloromonof luoromethane having a boiling point of about 75°F.

The process of the present invention can be applied to cured tobacco in the form of leaf (including veins and stems) , strips (leaf with stems removed) or cut filler (strips shredded for cigarette making) , ¾r using leaf or strips, the types or grades of tobacco can be selected for which the process is most effective, thereby achieving results near the maximum while holding processing costs to a minimum. Where treatment of stems is not necessary, strips are preferred rather than leaf, and in any event stems can be processed separately. If the entire blend is to be treated, then cut filler is preferably utilized.

The advantages of the invention are readily apparent from the foregoing. By the process of the invention, the filling capacity of tobacco can be significantly increased with the attending economic advantages. Vaporization and removal of the organic liquid from the impregnated tobacco at high tem<-peratures and short contact times permits the advantages of the invention to be realized with the use of minimum size equipment and with high production rates.

Those modifications and equivalents which fall within the spirit of the invention and the scope of the appended elalms are to be considered part of the invention.

Claims (22)

31884/3 What we claim is:

1. A process for increasing the filling capacity of tobacco which comprises providing tobacco moistened with or impregnated with a volatile organic liquid and removing the organic liquid by contacting said impregnated tobacco with a gas which is heated to a temperature of at least 30°F. above the boiling point of said organic liquid at the prevailing pressure to rapidly volatilize the organic liquid and expand the tobacco and separating the resulting hot gas stream from the expanded tobacco,

2. The process of claim 1 wherein the tobacco is impregnated with the organic liquid.

3. The process of claim 1 or 2 in which said gas is steam.

4. The process M claim 1, 2 or 3 in which the liquid is a hydrocarbon or a halogenated hydrocarbon.

5. The process of claim 1, 2, 3 or 4 wherein the tobacco is moist.

6. The process of any of the preceding claims wherein said gas is at a temperature between about 250°F and 400°F.

7. The process of any of the preceding claims wherein the heated gas is passed into contract with the impregnated tobacco.

8. The process of any of the preceding claims wherein the impregnated tobacco is contacted in a vertical column with the gas being flowed upwardly therethrough.

9. The process of any of the preceding claims wherein the hot gas carries the tobacco into a separator where the expanded tobacco is separated from the volatile organic liquid vapor. 31884/3

10. The process of any of the preceding claims wherein ί the volatile organic liquffd is employed in an amount between about 25 parts and 350 parts per 100 parts of tobacco (dry basis).

11. The process of claim 10 wherein the amount of volatile organic liquid is between abou$ 40 parts and 250 parts per 100 parts of tobacco (dry basis)

12. The process of any of the preceding claims wherein the volatile organic liquid is trichloromonofluorom ethane.

13. The process of any of the preceding claims wherein the volatile organic liquid separated from the expanded tobacco is recovered.

14. The process of any of the preceding claims wherein the impregnation with the volatile organic liquid is carried out at an elevated temperature below 170°F.

15. The process of any of claims 6-14 wherein contact of the impregnated tobacco with the hot gas effects said expansion of tobacco in a period of less than about 4 seconds.

16. The process of any of claims 6-15 wherein the moisture content of the tobacco before impregnation is maintained within the range of 10 to 100 parts by weight of water per 100 parts of tobacco (dry basis)*

17. The process of claim 16 wherein the moisture context of the tobacco before impregnation is maintained within the range of 18 to 30 parts by weight of water per 100 parts of tobacco (dry basis).

18. The process of any of claims 6-17 wherein the recovered expanded tobacco is steamed to remove residual organic liquid therefrom and the moisture content of the so-treated tobacco is then adjusted to a moisture content suitable for cigarette making.

19. The process of any of claims 6-18 wherein the gas passed into contact with the impregnated tobacco is heated to a temperature of at least about 200°F. above the boiling point of said liquid at 31884/3 the contacting pressure but below 400 F.

20. A process for increasing the filling capacity of tobacco substantially as herein described.

21. The process of any of claims 1 to 5 comprising contacting the moistened or impregnated tobacco with the heated gas by flowing a stream of said moistened or impregnated tobacco into a rapidly moving stream of said heated gas.

22. The process of claim 21 wherein the tobacco is