U.S. patent application number 10/380722 was filed with the patent office on 2004-04-22 for method for improving the filling capacity of tobacco.
Invention is credited to Fleischhauer, Holger, Klischat, Jurgen, Mulke, Bernd, Pienemann, Thomas.
Application Number | 20040074506 10/380722 |
Document ID | / |
Family ID | 7656639 |
Filed Date | 2004-04-22 |
United States Patent
Application |
20040074506 |
Kind Code |
A1 |
Fleischhauer, Holger ; et
al. |
April 22, 2004 |
Method for improving the filling capacity of tobacco
Abstract
The invention relates to a process for the improvement of the
filling capacity of tobacco such as shredded tobacco leaves or ribs
by treatment of the tobacco material having up to approx. 30 wt.-%
initial moisture with a treatment gas composed of nitrogen and/or
argon at pressures of 50 to 1,000 bar under continuous or stepped
compression, followed by a continuous or stepped decompression, the
compression and decompression steps taking place in either one
autoclave or in cascade-like sequence in several autoclaves, and by
subsequent thermal aftertreatment of the discharged tobacco
material, which is characterized in that the thermal aftertreatment
is carried out with a flowing heat-transferring medium of a mixture
of permanent gases and superheated water vapour, wherein the
proportion of permanent gas is kept constant at a value in the
range from 10 to 60 vol.-%.
Inventors: |
Fleischhauer, Holger;
(Hamburg, DE) ; Klischat, Jurgen; (Pinneberg,
DE) ; Mulke, Bernd; (Wedemark, DE) ;
Pienemann, Thomas; (Rosengarten, DE) |
Correspondence
Address: |
HOVEY WILLIAMS LLP
2405 GRAND BLVD., SUITE 400
KANSAS CITY
MO
64108
US
|
Family ID: |
7656639 |
Appl. No.: |
10/380722 |
Filed: |
March 14, 2003 |
PCT Filed: |
September 11, 2001 |
PCT NO: |
PCT/EP01/10498 |
Current U.S.
Class: |
131/294 ;
131/291 |
Current CPC
Class: |
A24B 3/182 20130101 |
Class at
Publication: |
131/294 ;
131/291 |
International
Class: |
A24B 003/18 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 15, 2000 |
DE |
100 46 124.7 |
Claims
1. Process for the improvement of the filling capacity of tobacco,
such as shredded tobacco leaves or ribs, by treatment of the
tobacco material having up to approx. 30 wt.-% initial moisture
with a treatment gas composed of nitrogen and/or argon at pressures
of 50 to 1,000 bar under continuous or stepped compression,
followed by a continuous or stepped decompression, the compression
and decompression steps taking place in either one autoclave or in
cascade-like sequence in several autoclaves, and by subsequent
thermal aftertreatment of the discharged tobacco material,
characterized in that the thermal aftertreatment is carried out
with a flowing heat-transferring medium of a mixture of permanent
gases and super-heated water vapour, wherein the proportion of
permanent gas is kept constant at a value in the range from 10 to
60 vol.-%.
2. Process according to claim 1, characterized in that essentially
air is used as permanent gas, and the air proportion is controlled
by means of a measurement of the oxygen content.
3. Process according to claim 2, characterized in that the air
proportion of the flowing heat-transferring medium is 20 to 50
vol.-%.
4. Process according to claim 2, characterized in that the air
proportion of the flowing heat-transferring medium is 25 to 40
vol.-%.
5. Process according to claims 1 to 4, characterized in that the
temperature of the heat-transferring medium is 120 to 300.degree.
C.
6. Process according to claims 1 to 5, characterized in that the
tobacco moisture of the pressure-treated tobacco is 8 to 25 wt.-%
prior to the thermal aftertreatment.
7. Process according to claims 1 to 6, characterized in that the
tobacco moisture is 8 to 15 wt.-% after the thermal
aftertreatment.
8. Process according to claims 1 to 7, characterized in that during
the thermal aftertreatment, hot steam is supplied in a closed
system according to the principle of stream-drying in which the
permanent gas is fed in downstream from the hot-steam feed in the
region of the discharge of heat-treated tobacco and is then
circulated in a closed cycle with more water vapour while
controlling the constancy of the proportion of permanent gas after
cooling of the expanded tobacco and discharging of same.
Description
[0001] The present invention relates to a process for the
improvement of the filling capacity of tobacco according to the
preamble of the main claim.
[0002] To improve the filling capacity of tobacco, the INCOM
swelling processes according to for example DE 31 19 330 A1, DE 34
14 625 C2 and DE 39 35 774 C2 have proved successful. In these
processes, tobacco, say in the form of shredded tobacco leaves or
ribs, with an initial moisture of up to approx. 30 wt.-%, is
subjected to a continuous or stepped compression with a treatment
gas composed of nitrogen and/or argon at pressures of 50 to 1,000
bar, followed by a continuous or stepped decompression. The
compression and decompression steps take place either in one
autoclave or in cascade-type sequence in several autoclaves. The
discharged tobacco material is then subjected to a thermal
aftertreatment in which the tobacco swells and the filling capacity
of the tobacco thus increases.
[0003] These INCOM processes have proved advantageous compared with
the pressure-treatment processes of tobacco with carbon dioxide,
ammonia or volatile organic compounds, as with the latter an
undesired dissolving of aromas or nicotine from out of the tobacco
material must be accepted, or residues of gases in the tobacco
material interfere with the taste or because ultimately, when using
carbon dioxide, the removal of the dry ice which forms upon
decompression is too energy-consuming.
[0004] With regard to the INCOM processes mentioned, DE 31 19 330
describes such an expansion process with working temperatures
prevailing in the autoclave of 0 to 50.degree. C., with provision
for the use of a tobacco material with a moisture of up to 15 wt.-%
and an aftertreatment with water vapour to increase the filling
capacity or degree of swelling. Furthermore, DE 34 14 625 C2 and DE
39 35 774 C2 disclose cascade processes in which a low working
temperature during the impregnation of the tobacco is effected by
cooling the treatment gas before loading the reactor, by cooling
the autoclave or by using a supercooled and liquefied treatment
gas.
[0005] With these known processes, the thermal aftertreatment is
carried out with water vapour of a density of 0.5 to 10 kg/m.sup.3,
preferably saturated steam, or with hot air of up to 440.degree.
C.
[0006] Although a process for the treatment of tobacco with carbon
dioxide at pressures of approx. 30 bar is known from EP 484 899 Bl,
in which the thermal aftertreatment takes place by feeding the
tobacco into high-temperature steam or into a gas containing 50 to
95 vol.-% water vapour upon heating of the tobacco in the flowing
medium at 200 to 350.degree. C., water or steam with a lower
temperature downstream from the tobacco feeding point being used to
reduce the temperature of the flowing medium. The tobacco dried to
a moisture of approx. 2 to 3 wt.-% by means of heat-transferring
flowing media is then reset to its normal moisture. As dry ice
forms upon the pressure treatment of the tobacco with carbon
dioxide after the decompression, the tobacco must be heated rapidly
for the thermal aftertreatment of the tobacco despite the high
evaporation enthalpy of the dry ice, which leads to a considerable
thermal and/or mechanical stress of the tobacco.
[0007] In the case of the INCOM process on which the present
invention is based, the tobaccos treated with nitrogen and/or argon
have a very much lower energy requirement for the desorption of the
absorbed gases and the associated swelling of the tobacco than the
tobaccos treated with CO.sub.2, so that in the case of the INCOM
process, in contrast to the CO.sub.2 process, no adverse effects on
taste occur. Furthermore, in the case of the thermal aftertreatment
of tobacco treated with nitrogen and/or argon, heat is transferred
by the condensation of water vapour on the cold tobacco and in the
further course of the thermal aftertreatment the desired moisture
content of the expanded tobacco is achieved by drying.
[0008] Nevertheless, also with the INCOM process there exists the
danger of over-moistening or overheating the tobacco with the
consequence of losses of filling capacity through collapsing of the
expanded cell structure.
[0009] The object of the invention is to carry out the thermal
after-treatment of the tobacco treated with nitrogen and/or argon
in the INCOM process such that a uniform product quality with
optimum filling capacity is achieved.
[0010] To achieve this object, a process is therefore proposed
according to the preamble of the main claim, which is characterized
in that the thermal aftertreatment is carried out with a flowing
heat-transferring medium consisting of a mixture of permanent gases
and superheated water vapour, wherein the proportion of permanent
gas is kept constant at a value in the range from 10 to 60
vol.-%.
[0011] By permanent gas is meant in this context any gas which can
be used together with water vapour when drying, such as air,
optionally mixed with nitrogen and/or argon or other inert
gases.
[0012] Surprisingly, it has been shown that the proportion of
permanent gas in the mixture with superheated water vapour is an
essential parameter to achieve optimum filling capacity values
under the given process conditions and in particular in a
stream-drying process.
[0013] Preferably, air is essentially used as permanent gas, the
air proportion being controlled indirectly by means of a
measurement of the oxygen content. The air proportion of the
flowing heat-transferring medium preferably amounts to 20 to 50
vol.-% and in particular 25 to 40 vol.-%.
[0014] Preferably the temperature of the heat-transferring medium
is to lie at 120 to 300.degree. C., and the tobacco moisture of the
pressure-treated tobacco is to be 8 to 25 wt.-% before the thermal
aftertreatment. Furthermore, it is expedient if the tobacco
moisture is 8 to 15 wt.-% after the thermal aftertreatment.
[0015] In a particularly preferred embodiment of the process
according to the invention, the procedure is that in the thermal
aftertreatment, the hot steam is supplied in a closed system
according to the known principle of stream drying in which the
permanent gas is fed in downstream from the hot-steam feed in the
region of the discharge of the heat-treated tobacco and is then
circulated in a closed cycle with more water vapour while
controlling the constancy of the proportion of permanent gas after
cooling of the expanded tobacco and discharging of same. In
particular, a rapid lowering of the tobacco temperature and thus
the fixing of the filling capacity is thereby achieved.
[0016] In the following, a preferred process using a customary
stream-drier is explained with reference to the schematic diagram
reproduced in FIG. 1, wherein air was used as permanent gas and its
proportion was determined indirectly via an oxygen measurement.
[0017] Depending on local pressure difference between the
heat-transferring medium conducted in the cycle and the
surroundings, external air is sucked in in the region of the entry
(1) and discharge ports (2) and vapours discharged via a vapour
flap (3). The feeding-in of the superheated steam takes place via a
steam valve (4). The oxygen content in the heat-transferring medium
was measured with a probe (5). By control of the steam valve (4) as
well as the vapour flap (3), the desired oxygen content and thus a
constant ratio of permanent gas to super-heated steam can be
established.
[0018] With reference to the following embodiment, the relationship
between filling capacity and the permanent gas proportion in the
heat-transferring medium is demonstrated. The permanent gas
proportion necessary in each individual case to achieve an optimum
filling capacity depends on the type and the moisture of the
tobacco material used as well as on the boundary conditions of the
apparatus.
EXAMPLE
[0019] Tobaccos treated with a stream-drier according to FIG. 1
according to the INCOM process were thermally after-treated as
follows. The mass flow of the tobacco introduced was 1250 kg/h, the
volume flow of the circulating heat-transferring medium consisting
of superheated steam and air 7315 m.sup.3/h. The proportion of
steam and permanent gas deducible via the measurement of the oxygen
content was varied, with constant performance of the heater
according to a graduation of the oxygen content of 1.3, 7.5 and 15
vol.-% corresponding to a permanent gas proportion of 6.5 or 37 or
75 vol.-% respectively and an associated contrary change of the
initial temperature measured before the introduction of tobacco in
the range from 185 to 165.degree. C.
[0020] The filling capacity of the discharged and conditioned
tobacco was determined with a Borgwaldt densimeter and the specific
volume converted to ml/g at a nominal moisture of 12 wt.-% and a
nominal temperature of 22.degree. C. The relative filling capacity
improvement was calculated as follows from the data of the basic
experiment without permanent gas and the expanded samples with
heat-transferring media of steam and permanent gas:
.DELTA.%=(F.sub.E-F.sub.B) * 100%/F.sub.B
[0021] (F.sub.B=filling capacity, basic experiment, steam without
permanent gas, F.sub.E=filling capacity, expanded, steam with
permanent gas)
[0022] The diagram shows the relationship between the filling
capacity of the expanded tobacco and the process variable of the
oxygen content in the heat-transferring medium and the possibility
of being able to establish optimum process conditions with the help
of this process variable.
* * * * *