DE3523825A1 - IMPROVED TOBACCO EXPANSION PROCESS - Google Patents

Description

Improved Tobacco Expansion Process Description

The invention relates to an improved tobacco treatment method and more particularly to an improved method of expanding tobacco in which the tobacco is grown on a relatively high moisture content is maintained.

A number of methods are known in the art, in which the expansion of tobacco takes place in that the tobacco with a liquefied gas, such as carbon dioxide, is soaked under pressure to introduce the gas as a liquid into the tobacco. Once the print on the so soaked Tobacco is reduced, the liquefied gas turns into a solid, and the tobacco is then expanded, when the solid is evaporated. For example, one such method is shown in U.S. Patent Nos. 4,336,814 and 4,340 as well as in a number of prior patents and publications mentioned in these patents. In addition, a number of patents and patent applications are known in the art which provide structural arrangements for Implementation of the expansion of saturated tobacco in pipe systems and teach associated drying chambers. These are, for example, U.S. Patents No. 3,357,436, No. 3,786,573, No. 4,366,825 and a number of prior patents mentioned in these patents. The U.S. patent applications also disclose No. 391 882 and No. 541 752 structural assemblies used to expand soaked tobacco in pipe systems and in connection standing drying chambers can be used.

These patent applications also describe a tobacco loading device, the device essentially at the inlet of a separator for introducing to be dried and to be expanded Tobacco is arranged in the pipeline at the inlet of the separator device.

The invention recognizes certain disadvantages of known methods of expanding tobacco and provides an improved method for expanding tobacco with less loss of tobacco bulk capacity or value, accompanied by reduced losses of glycerine, alkaloids and sugar. In addition, the inventive effect Process a reduction in the tobacco temperature at the dryer outlet while achieving high particle expansion as well as higher tobacco moisture content at the dryer exit with resulting larger and less friable particles. Because of the higher tobacco moisture content at the dryer exit as a result of the invention, there is only one, if any minor reconditioning is required to bring the moisture content of the expanded tobacco product to the desired level to bring the final measure. There is also less cooling and, accordingly, less energy required to keep the tobacco product on Bring the output to an acceptable storage temperature. Since little or no keconjitioning of the tobacco is required In order to provide the expanded product with the desired final moisture, little or no water needs to be added so that, as a result, the loss of bulkiness is greatly reduced.

Various other features of the invention will become apparent to those skilled in the art upon reading the disclosure below.

In particular, the invention provides an improved tobacco treating method comprising the steps of conditioning the tobacco to a preselected moisture content sufficient to achieve a moisture content of the finished tobacco in the range of about 9 % to about 15 % volatile in the drying oven and a fill value, which is at least equivalent to the fill value of one to one

! ο lower moisture range of dried tobacco, of soaking of the conditioned tobacco with liquefied gas under pressure and temperature and reducing the pressure to an extent that is sufficient is for forming a solid within the tobacco and treating the tobacco soaked with the solid with pressure and temperature during a preselected, limited dwell time in the pre-separator of less than 0.1 second, wherein the solid material evaporates, thereby causing an expansion of the tobacco and a finished tobacco is produced which a moisture content ranging from about 9% to about

2Q has 15 % volatile constituents in the drying oven and a filling value which is at least equivalent to the filling value of a tobacco dried to a lower moisture range with a longer residence time in the pre-separator.

It goes without saying that various changes may be made in the various stages of the present invention disclosed herein Method by the person skilled in the art without departing from the inventive concept and scope of the invention can be practiced.

Q ₃ In carrying out the process of the invention may be any of various methods known in the prior art construction arrangements are used, including certain of these arrangements, which in the above patents and

Patent applications relating to the expansion of soaked tobacco in pipe systems and associated, connected drying chambers are disclosed. Accordingly, in the interests of brevity, no details are given here Construction arrangements described. It should be noted that the structural arrangement required for the installation of the Comparative data listed in Table 1 below lead to

Conventional prior art methods are used is similar to that disclosed in Fig. 4 of the aforesaid patent application Ser. No. 541,752. the Construction arrangement for the leading to the establishment of the data listed in the following Tables 2, 3 and 4 according to the invention The method used is similar to the structural arrangement disclosed in Figure of the aforesaid patent application No. 541,752.

In general, according to the method according to the invention, it becomes be-2Q trading tobacco with a mixture, for example of water and glycerine, conditioned to a moisture content, which is greater than the conventional moisture content of tobacco to be cut. Up to this conventional moisture content conditioned tobacco has "O.V." or volatile components in the drying oven (the determination was made by the weight loss of a in a preheated forced air oven at 110 ° C for three and a quarter Hours dried sample) of approximately 20 percent by weight. According to the invention, the conditioning step becomes so controlled so that a tobacco is produced which has a higher moisture oQ than such a conventional moisture content for too having cutting tobacco, or that the tobacco to a moisture range of about 22 weight percent to about 26 percent by weight, preferably up to about 25 percent by weight, is conditioned.

The conditioned tobacco is made according to the method of the invention then with about 30 cuts per 25.4 mm (30 cuts per inch) and soaked in liquid carbon dioxide under pressure. Then the pressure is reduced so far that solidified carbon dioxide forms inside the tobacco. The tobacco soaked with the solidified carbon dioxide mentioned above In contrast to conventional expansion devices (expanders), moisture then remains in an expansion device for a longer period of time (Expander) treated with an ultra-short dwell time under preselected pressure and temperature conditions, so that the Solidified carbon dioxide sublimes or evaporates and an expansion of the tobacco causes a finished treated expanded tobacco with a moisture content in the range of about 9 weight percent to about 15 weight percent volatiles is produced in the drying oven. This moisture content is higher than the normally found moisture content in the range of 1% to 6% volatile matter in the drying oven. As can be seen from Tables 2 to 4 below is, this increased moisture of the finished tobacco leads to an improvement in the particle size, since the Particles are less brittle and crumbly, and reduce the loss of glycerine, alkaloids and total sugar, because the tobacco temperature is due to the combination of high humidity and a comparatively ultra-short residence time in the expansion device is lower.

To illustrate the improvements resulting from the implementation of the various QQ steps of the invention, four examples, each with an attached table of data, are described below, Table 1 of Example 1 listing test results which include almost conventional residence times in the pre-separator. It is noted here that _the% reduction in residence time of 0.7 see Table 1 according to see 0.06

according to Tables 2, 3 and 4 in the examples shown, mainly due to a reduced residence time in the pre-separator with the residence time in the separator being essentially the same for all examples described below. Usually the residence time in the separator itself is approximately 1.4 see. It should also be noted that the following Results of the Borgwaldt filling

IQ value tests were determined by compressing sample tobacco with a specified weight in a cylinder under a 3 kg (free fall) load for a period of 30 seconds. The sample weight and the height of the compressed tobacco column were used to calculate the filling value in cm ³ / g. The measured values for the particle size distribution (PSD) listed in the tables were generally determined by placing a weighed amount of tobacco on the top sieve of a ro-tap device and then passing through a number of successive Tyler sieves with the specified, preselected mesh size

2Q was sifted through.

example 1

In this example, a tobacco blend of 50 % pipe-dried and 50 % Burley tobacco was conditioned to the moisture range given in Table 1 (A to F). The conditioned tobacco was then cut at 30 cuts per 25.4 mm (30 cuts per inch) and with liquid carbon dioxide at pressures ranging from about 26 kg / cm ² to about 30 kg / cm ² and temperatures of about -10 ° C to about -5 ° C soaked. After the impregnation was complete, the pressure was released, as a result of which the liquid carbon dioxide inside the tobacco was converted into a solid mass. The frozen one

X / IA.

Tobacco was then de-lumped, passed through an equalizing storage room and over a belt scale, and into an expander / tangential separator brought in.

As disclosed in FIGS. 3 and 4 of patent application no. 541 752, the introduction of the frozen tobacco into the drying system took place through a rotary air lock leading into a horizontal pipe. The pipeline followed a 90 ^G bend, rose vertically, followed a 90 ° bend again, and was then connected to a tangential separator. The residence time in the pipeline was approximately 0.7 seconds. The residence time in the separator corresponded to a conventional value, namely approximately 1.4 seconds. The expanded tobacco then became a Re-15

conditioning cylinder supplied, in which the moisture with a water spray from 10 ° C to 16 ° C and cooling air from 21 ° C to about 12 weight percent volatiles in the drying oven was discontinued.

As from the measurement results shown in the table below of Example 1 can be seen, with the comparatively longer residence time of 0.7 seconds in the pre-separator even higher dryer inlet humidities of about 25 weight percent the moisture at the dryer outlet is not felt

raise. In addition, the comparison of the test series A to F can

Table 1 with the test series B and C of Table 2 and the test series B of Tables 3 and 4, which are a comparatively shorter one Dwell times of 0.06 seconds and higher dryer inlet humidities of about 25 weight percent include only ge-30

will see improvements, if any, in the particle size distribution. Furthermore, the test series show D, E and F of Table 1 in comparison with test series B and C of the table 2 and the test series B of Tables 3 and 4 no noticeable improvements in terms of reduced percentage losses

of glycerine, alkaloids and sugar.

Table 1

0.7 0.7 0.7 0.7 0.7 0.7 327
(620) 329
(625) 329
(625) 332
(630) 329
(625) 329
(625) 34.5
(76M) 34.5
(76M) 34.5
(76M) 34.5
(76M) 34.5
(76M) 34.5
(76M) 1479
(3260) 1515
(3340) 1383
(3050) 1597
(3520) 1597
(3520) 1520
(3350) 21.3 22.7 22.6 25.8 24.8 23.7 1.8 1.6 2.1 2.3 3.0 1.2 4.09 3.85 4.26 - 3.87 4.36 7.44 7.29 6.92 _ 6.85 7.24 82 89 62 _ 77 66

Dryer data:

Residence time (see) in the pre-separator

Inlet gas temperature ⁰ C ( ⁰ F)

Gas throughput kg / h (lb./hr.)

Solid throughput kg / hr dry (lbs / hr dry)

Moisture (wt. S) at the start of the process

Separator airlock outlet

Borgwaldt fill value (σηVg at 14 % moisture) at the start of the process

Reconditioning cylinder outlet expansion (%)

2Q distribution of particle size (Tyler)

Reconditioning cylinder outlet

+ 9 stitches per 25.4 m (+ 9 mesh) (%) -14 stitches per 25.4 rm (-14 mesh) {%)

",

Glycerine:

(kg glycerine / kg dry tobacco)

Start of proceedings 3.8 3.1 - 5.6 6.7 4.3

Outlet of the
Reconditioning cylinder 2.4 2.2 - 4.0 3.8 3.3

30 Loss {%) 37.0 29.0 - 29.0 43.0 23.0

Alkaloids {%)
Start of proceedings 3.13 3.13 3.13

Outlet
of the reconditioning cylinder 1.93 1.93 j.93 _

³⁵ Loss {%) 38.0 38.0 38.0

46 42 45 45 52 47 23 24 23 24 19th 21

X 4Z. B. C. D. 5523825 (still table 1) A. 6.8 6.8 - E F Total sugar {%) Start of proceedings 6.8 5.5 5.5 - - Outlet 19.0 19.0 - of the iteconditioning cylinder 5.5 - Loss (%) 19.0 Example 2

Tobacco was treated as in Example 1 with the exception that the frozen tobacco was placed in the drying tube immediately before the tangential separator. As a result, the residence time was in the pre-separator 0.06 seconds compared to 0.7 seconds according to

Game 1, Table 1. It goes without saying that such a shorter residence time is advantageously in the range of about 0.01 can be up to 0.1 see.

As can be seen from Table 2, the test series 2A to

conditioned to a moisture content of about 20 weight percent volatiles in the drying oven, whereas the test series 2B and 2C to a moisture content of about 25 weight percent volatile components were conditioned in the drying oven. Different gas temperatures at the dryer inlet were used for the test series 2A, 2B and 2C are used. The increase in moisture at the separator outlet for the test series 2B and 2C compared to the test series 2A should be noted. Furthermore, the increase should the percentage Borgwaldt fill value when comparing the test series 2B and 2C are observed with the test series 2A. Furthermore, when comparing test series 2B with test series 2A, the Improvement in the distribution of particle size should be noted. Furthermore, when comparing the test series 2B and 2C with the test series 1A, 1B, 1D, 1E and 1F of Table 1 show the reduction in glycerol loss and when comparing test series 2B and 2C with test series 2A, the reduction in the losses of alkaloids and Sugar should be noted. Likewise, when comparing the

Test series 2C and 2A show the reduced requirements for the reconditioning spray as well as those resulting from the comparison the drop in tobacco temperatures resulting from the test series 2B and 2C with the test series 2A.

Dryer data:
Dwell time in
Pre-separator (sec) 0.06 Table Ie 2 0.06 B. 0.06 0.06 C. 0.06 10 Inlet gas temperature ⁰ C
( ⁰ F) 264
(508) A. 264
(508) 0.06 329
(625) 268
(515) 0.06 342
(647) Gas throughput kg / hour
(lb./hr.) 34.5
(76Nt) 0.06 0.06 34.5
(76M) 294
(562) 34.5
(76M) 34.5
(76M) 305
(582) 34.5
(76M) Solid State Throughput
kg / str. dry
(lbs./hr. dry) 1397
(3080) 297
(566) 329
(624) 1315
(2900) 34.5
(76M) 1315
(2900) 1678
(3700) 34.5
(76M) 1678
(3700 15th Reconditioning data: 34.5
(76M) 34.5
(76M) 1315
(2900) 1678
(3700) Total water sprayed
ltr./hour
(GPH) 83.3
(22) 1397
(3080) 1397
(3080) - - 22.7
(6) 136.3
(36) 20th sprayed water
(kg water / 1000 kg tobacco, - 60 - - - 14th 87.1
(23) 81 Tobacco temperature ⁰ C
( ⁰ F)
Separator outlet
Airlock 79
(175) 128.7
(34) 155.2
(41) 68
(155) - 79
(175) 71
(160) 52 78
(172) Moisture (wt.%) 92 111 74
(165) 77
(170) 25th Start of proceedings 20.3 88
(190) 91
(195) 24.7 24.7 24.8 24.8 Outlet of
Separator airlock 9.3 10.1 24.7 6.3 14.5 24.8 7.2 20.2 20.2 8.7 10.2 30th 7.1 3.5

Borgwaldt fill value
(σηVg at 14 % humidity.)

Start of proceedings 4.61 4.61 4.61 4.52 4.52 4.52 4.50 4.50 4.50

Outlet
of the reconditioning cylinder 7.8Ο 8.05 8.15 7.75 8.05 8.25 7.44 8.05 8.39

% Expansion 69.0 75.0 77.0 71.0 78.0 83.0 65.0 79.0 86.0

(Table 2) (continued)

Particle size distribution (Tyler)

Outlet ..

of the (conditioning cylinder + 9 meshes / 25.4 m (+ 9 rresh) {%)

- 14 mesh / 25.4 rm (-14 mesh) (%)

glycerin

(kg glycerine / kg dry tobacco)

Start of proceedings

Reconditioning cylinder outlet

% Loss

41 37 49 50 52

23 26 20 18 17

2.87 2.87 2.87 3.17 3.17 3.17

2.93 2.78 2.61 3.06 2.97 2.83 0 3.0 8.0 3.0 6.0 11.0

Alkaloids (%) Start of process Outlet of the reconditioning cylinder

% Loss

2.91 2.91 2.91 2.95 2.95 2.95 2.97 2.97 2.97

2.46 2.42 2.24 2.68 2.56 2.33 2.76 2.69 2.47 15.0 17.0 23.0 9.0 13.0 21.0 7.0 9.0 17.0

Total sugar {%) start of process outlet of the reconditioning cylinder

% Loss

7.7 7.7 7.7 7.8 7.8 7.8 7.3 7.3 7.3

7.5 6.6 6.7 7.8 7.5 7.5 7.2 7.2 6.6 3.0 14.0 13.0 0 4.0 4.0 1.0 1.0 10.0

Example 3

Tobacco was treated as in Example 2, as shown in the following As seen in Table 3, Series 3A were run to an approximate moisture content of 21.5 percent by weight volatiles 35 in the drying oven, the test series 3B, on the other hand, conditioned to an approximate humidity of approximately 25 percent by weight. Like in

12-4 & 5523825

Example 2 should have increased humidity and lower temperature at the outlet of the separator for test series 3B compared to test series 3A as well as the lower water consumption for the reconditioning must be observed. Further, when comparing Test Series 3B with Test Series 3A, the percentage increase is Borgwaldt fill value to be noted. In addition, when comparing test series 3B with test series 3A, the reduction the losses of glycerine, alkaloids and total sugar are taken into account.

Table 3 Dryer data: A. 0.06 0.06 0.06 B. 0.06 Residence time (see) im
Pre-separator 322
(612) 333
(631) 299
(570) 307
(584) Inlet gas temperature ⁰ C
( ⁰ F) 34.5
(76M) 34.5
(76M) 34.5
(76M) 34.5
(76M) Gas throughput kg / hour
(lb./hr.) 1842
(4060) 1842
(4060) 1914
(4220) 1796
(3960) Solid throughput kg / hour dry
(lb./hr. dry)

f ^ onditionierungsdaten:

Total water sprayed (l / hour) 196.8 208.2 124.9 117.3

(GPH) (52) (55) (33) (31)

Water sprayed fkg water / 1000 kg tobacco] 107 113 65 65

Tobacco temperature

Separator airlock outlet ⁰ C 82 79 71 76

(° F) (180) (175) (160) (168)

Moisture (wt.%)

Start of proceedings 21.6 21.6 24.9 24.9

Separator air lock outlet 5.9 4.5 9.3 9.1

( Table 3) (continued

Borgwaldt filling value (cmVg at 14 % humidity) at the beginning of the process outlet of the reconditioning cylinder expansion (%)

Glycerine:

(kg glycerine / kg dry tobacco) start of the process

Reconditioning cylinder outlet loss {%) 4.82 4.82 4.27 4.27

7.72 7.94 6.96 7.11 60.0 65.0 63.0 67.0

2.38 2.38 3.35 3.35

2.09 2.07 3.11 3.13 12.0 13.0 7.0 7.0

Alkaloids {%) Start of process Outlet of the reconditioning cylinder

Loss (%).

2.93 2.93 2.87 2.87

2.47 2.42 2.72 2.69 16.0 17.0 5.0 6.0

Total sugar (%) Start of process Outlet of the reconditioning cylinder Loss {%) 8.7 8.7 8.5 8.5

9.2 8.4 9.1 9.4
0 3.0 0 0

Example 4

Tobacco was treated as in Examples 2 and 3. As can be seen from Table 4 below, the test series 4A more volatile to approximate moisture levels of 22 percent by weight Components in the drying oven.disTestreihen 4B, however, up to an approximate Moisture of 24.5 percent by weight more volatile

Components conditioned in the drying oven. When comparing the Testreilieri 4B init 4A, the improvements should in particle size and the expan sion _c and the reduction of losses of glycerol, alkaloids and total sugar observed. The decrease in airlock temperatures at the outlet of the separator and the amount of water required for reconditioning should also be noted.

Tabel

Dryer data A B

Residence time (see) in the pre-separator, inlet gas temperature ⁰ C

! 6 <° ^F)

Gas throughput kg / h

(lb./hr.)

Solid throughput kg / h dry (lb./hr. dry)

I ^ conditioning data

Total water sprayed l / h (GPH)

sprayed water fkg water / 1000 kg tobacco)

²⁵ Tobacco temperature ⁰ C 79 79 66 71

(° F) (175) (175) (150) (160)

Separator airlock outlet

Humidity (Gsw.X)

30 Start of proceedings 21.8 21.8 24.5 24.5

Separator airlock outlet 6.7 5.6 11.5 10.4

0.06 0.06 0.06 0.06 321
(610) 333
(631) 288
(550) 304
(580) 34.5
(76M) 34.5
(76M) 34.5
(76M) 34.5
(76M) 1769
(3900) 1769
(3900) 1814
(4000) 1814
(4000) 189.2
(50) 200.6
(53) 49.2
(13) 83.3
(22) 107 113 27 46

Table 4 (continued)

Borgwaldt fill value

(cnVg at 14 % moisture) Start of the process

Reconditioning cylinder outlet

% Expansion

Particle size distribution (Tyler)

Outlet of the reconditioning cylinder + 9 mesh / 25.4 rrm (+ 9 mesh) (%) - 14 mesh / 25.4 m (-14 mesh) [%) 4.91 4.91 4.42 4.42

8.34 8.51 7.68 8.06 70.0 74.0 74.0 82.0

43 22

44 23

Glycerine (kg glycerine / kg dry tobacco)

Start of proceedings

Reconditioning cylinder outlet

Loss {%) 2.36 2.36 2.06 2.06

2.19 2.19 1.99 1.93 7.0 7.0 3.0 6.0

Alkaloids (%) start of the process

Reconditioning cylinder outlet

Loss (X) 3.05 3.05 3.01 3.01

2.56 2.48 2.81 2.69 16.0 19.0 7.0 11.0

Total sugar [%) start of the process

Reconditioning cylinder outlet

Loss (%) 9.5 9.5 9.4 9.4

8.5 8.5 8.8 9.1 11.0 11.0 6.0 3.0

Taking into account the fact that all expanded products were reconditioned to a final moisture content of 12% volatile constituents, it can be seen from the examples described above and the respective measurement results in the tables that the method according to the invention creates a tobacco treatment method which is a better one Control of the particle size and the losses of glycerol, alkaloids and total sugar enables an improved

Tobacco fill value leads to less water spray at the same time 10

and refrigeration required for reconditioning and storage of the tobacco.

Claims (12)

BROWN & WILLIAMSON TOBACCO CORPORATION Brown & Williamson Tower Louisville, Galleria Louisville, Kentucky MQ202 USA PR1 H N'EfE ^ - ^ L 'DH W BOTlt BCO DR V Kl1JKEwDEv P 19 563-006 / st Improved Tobacco Expansion Process Claims 1. An improved tobacco treating process, characterized by the steps of conditioning the tobacco to a preselected moisture content sufficient to achieve a moisture content of the finished tobacco in the range of about 9% to about 15 % volatiles in the drying oven and a fill value that is at least equivalent to the fill value of a tobacco dried to a lower humidity range, soaking the conditioned tobacco with a liquefied gas, preferably liquid carbon dioxide, under pressure and temperature and reducing the pressure by an amount that is sufficient to form solidified gas , preferably carbon dioxide, inside the tobacco, and treating of the tobacco soaked with the solidified gas, preferably carbon dioxide, with pressure and temperature during a preselected, limited residence time in the pre-separator of less than 0.1 second, the solidified gas, preferably Carbon dioxide, evaporates, thereby causing the tobacco to expand and producing a finished tobacco that has a moisture content in the range of about 9 weight percent to unge-2Q has around 15 percent by weight of volatile constituents in the drying oven and a fill value that is at least equivalent to the filling value of a tobacco dried to a lower moisture range with a longer residence time in the pre-separator. p. 2. The method according to claim 1, characterized in that that the conditioning is carried out with a mixture of glycerine and water. 3. The method according to claim 1 or 2, characterized in that the tobacco is conditioned so that it has a moist Has activity content of about 25 percent by weight. 4. The method according to at least one of claims 1 to 3, characterized in that the tobacco is a mixture of 50 Ge _nc weight percent rohrgetrockneteni tobacco and 50 percent by weight Burley Includes tobacco. 5. The method according to at least one of claims 1 to 4, characterized in that the process step of through soak with liquefied gas, preferably carbon dioxide 30th a pressure in the range of about 26 kg / cm ² (370 psig) to about 30 kg / cm ² (425 psig); and a temperature in the range of about -10 ° C (14 ° F) to about -5 ° C (23 ° F). 6. The method according to at least one of claims 1 to 5, characterized in that the finished treated tobacco one Moisture content of approximately 11 % volatile matter in the 5th Has drying oven. 7. The method according to at least one of the claims! to 6, characterized in that the with solidified gas, preferably Carbon dioxide, impregnated tobacco is subjected to evaporation in the pre-separator and in the separator, the residence time in the pre-separator is about 0.01 second to about 0.1 second. 8. The method according to at least one of claims 1 to 7, characterized in 15 characterized in that the tobacco impregnated with solidified gas, preferably carbon dioxide, undergoes evaporation in the pre-separator and is subjected in the separator, the residence time in the pre-separator being approximately 0.06 seconds and the residence time in Separator is approximately 1.4 seconds.
20th 9. The method according to at least one of claims 1 to 8, characterized in that the conditioned tobacco with approximately 30 cuts per 25.4 mm (30 cuts per inch) is cut. 10. The method according to at least one of claims 1 to 9, characterized characterized in that the expanded tobacco, if necessary, to a moisture content of at least about 12 percent by weight of volatile components is reconditioned in the drying oven. 11. The method according to at least one of claims 1 to 10, characterized characterized in that the tobacco prior to soaking with liquid gas, preferably carbon dioxide, an inlet moisture from about 22 percent to about 26 percent by weight. 12. Improved tobacco treatment process characterized by the steps of conditioning the tobacco with
p- a mixture of glycerine and water, the tobacco being a
Moisture content of about 25 weight percent, of soaking the conditioned tobacco with a liquefied gas. preferably liquid carbon dioxide, at a pressure in the range of about 26 kg / cm ² (370 psig) to about 30 kg / cm ² (425 psig) and a temperature in the range of about -10 ° C (14 ° F) to about - 5 ° C (23 ° F) and then reducing the pressure by an amount sufficient to form solidified gas, preferably carbon dioxide, within the tobacco and the
Subjecting the tobacco impregnated with the solidified gas, preferably carbon dioxide, to evaporation in the pre-separator and in the separator with a residence time in the pre-separator of approximately 0.01 to approximately 0.1 seconds to produce a finished tobacco with a moisture content of approximately 11 %
volatile constituents in the drying oven and a filling value which is at least equivalent to the filling value of a tobacco dried with a longer residence time in the pre-separator to a lower moisture content.