EP0404473A2 - Procédé d'expansion du tabac - Google Patents

Procédé d'expansion du tabac Download PDF

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Publication number
EP0404473A2
EP0404473A2 EP90306602A EP90306602A EP0404473A2 EP 0404473 A2 EP0404473 A2 EP 0404473A2 EP 90306602 A EP90306602 A EP 90306602A EP 90306602 A EP90306602 A EP 90306602A EP 0404473 A2 EP0404473 A2 EP 0404473A2
Authority
EP
European Patent Office
Prior art keywords
tobacco
expansion
sulfur hexafluoride
zone
impregnated
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP90306602A
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German (de)
English (en)
Other versions
EP0404473A3 (fr
Inventor
Anatoly Ilich Kramer
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
RJ Reynolds Tobacco Co
Original Assignee
RJ Reynolds Tobacco Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US07/459,007 external-priority patent/US5031644A/en
Application filed by RJ Reynolds Tobacco Co filed Critical RJ Reynolds Tobacco Co
Publication of EP0404473A2 publication Critical patent/EP0404473A2/fr
Publication of EP0404473A3 publication Critical patent/EP0404473A3/fr
Withdrawn legal-status Critical Current

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    • A—HUMAN NECESSITIES
    • A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
    • A24B—MANUFACTURE OR PREPARATION OF TOBACCO FOR SMOKING OR CHEWING; TOBACCO; SNUFF
    • A24B3/00—Preparing tobacco in the factory
    • A24B3/18—Other treatment of leaves, e.g. puffing, crimpling, cleaning
    • A—HUMAN NECESSITIES
    • A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
    • A24B—MANUFACTURE OR PREPARATION OF TOBACCO FOR SMOKING OR CHEWING; TOBACCO; SNUFF
    • A24B3/00—Preparing tobacco in the factory
    • A24B3/18—Other treatment of leaves, e.g. puffing, crimpling, cleaning
    • A24B3/182—Puffing

Definitions

  • the invention relates to a process for tobacco expansion. More specifically, the invention relates to a process for expanding tobacco to reduce its bulk density and thereby increase its volume and filling capacity. The process is especially suitable for treating cigarette cut filler.
  • U.S. Patent No. 4,461,310 to Zeihn and U.S. Patent No. 4,289,148 to Zeihn describe the expansion of tobacco employing supercritical nitrogen or argon impregnation of tobacco. These gases are removed from the tobacco during a rapid pressure reduction and the tobacco is expanded by exposure to heated gas or microwave. These processes require treatment of tobacco at pressures in excess of 2,000 or 4,000 psi up to above 10,000 psi in order to achieve substantial tobacco expansion.
  • the invention provides a tobacco expansion process which employs sulfur hexafluoride as the expansion agent. It has been found that sulfur hexafluoride can be used to expand tobacco without substantial physical harm to the tobacco and without significant change of tobacco taste and flavors.
  • the process of the invention is conducted by impregnating tobacco with sulfur hexafluoride which is advantageously in liquid form and maintained at a pressure of greater than about 300 psi. Preferably, the impregnation step is conducted at a pressure of between about 350 psi and 2500 psi.
  • the impregnated tobacco is discharged from the impregnation zone at a temperature between about -40°C and about 35°C, preferably between about -25°C and about 20°C.
  • the expansion agent used in the process of this invention is an odorless, tasteless, colorless and nontoxic gas at room temperature. At atmospheric pressure it sublimes from a solid to gas at -64°C. Despite the low sublimation point of this material, it has been found that sulfur hexafluoride is retained by tobacco at temperatures between -30°C and 30°C, advantageously between -20 and 20°C, for short periods of time, thus allowing time for transport of impregnated tobacco to a heated expansion zone or for the temporary storage of the impregnated tobacco in an insulated or refrigerated holding zone. Typically, sulfur hexafluoride is retained in the tobacco in amount ranging from about 0.5% by weight to about 20% by weight.
  • Still another benefit of the expansion process of the invention is that under the impregnation temperatures and pressures employed herein, there is advantageously little if any extraction of valuable flavor components from the tobacco during the impregnation step.
  • the tobacco removed from the impregnation zone can advantageously be in a substantially unextracted condition. This preserves the taste of the expanded tobacco and also allows for simplification of impregnant recovery steps.
  • Tobacco to be treated in the expansion process of the invention can be provided in any of various forms, for example in the form of leaf, strip or cigarette cut filler.
  • Shredded tobacco of 20 to 40 cuts per inch, i.e., cut filler is preferred because the process is more effective with this smaller particle size and also some of the increase in filling capacity may be lost if expanded tobacco in the form of leaf or strip were subsequently run through a cutter or shredder.
  • the tobacco may be cased with various flavorants, humectants and the like prior to expansion treatment.
  • the tobacco to be treated should be in a pliable condition to minimize breakage or shattering during handling and processing.
  • the traditional way of making tobacco pliable is to adjust the water content to within the range of between about 10 and 30%, preferably between about 20 and about 30% moisture. Higher moisture contents also can be, and advantageously are, employed in the process of the invention, particularly when microwave treatment is used to expand the tobacco.
  • the liquid sulfur hexafluoride removed from the impregnator is passed via line 31 through a pump 34 and following any necessary treatment for removal of solids, moisture, or other contaminants, is returned to supply vessel 14 .
  • the tobacco is carried by the force of the hot gas stream upwardly through expansion zone 48 and into separator 50 .
  • the sulfur hexafluoride rapidly volatilizes from the tobacco resulting in the stable expansion of the tobacco.
  • the degree of heating of the tobacco within expansion zone 48 is advantageously kept to a minimum to avoid harming the tobacco flavor and/or to avoid excessive fines generation. Temperatures above 300°C are preferably avoided in the expansion zone in order to prevent evaporation of excessive moisture from the tobacco and to prevent overheating of the tobacco, although the skilled artisan will recognize that such temperatures can be used, if desired.
  • the expansion zone will contain heated gases at a temperature of between about 90°C and about 250°C, preferably between about 100°C and 225°C, most preferably between about 100°C and 200°C.
  • the expanded tobacco can be passed to a reordering zone and/or a sulfur hexafluoride recovery zone.
  • the reordering process comprises a moisture treatment in which expanded tobacco is treated with steam, water vapor or the like in order to increase the moisture content of the tobacco to the desired range of 10%-13%.
  • the expanded tobacco exiting separator 50 will contain only a minute amount of residual sulfur hexafluoride, for example, 0.15% by weight or less.
  • the treatment to increase moisture content provided in conditioning drum 102 is conducted in order to provide sufficient moisture in the tobacco for later absorption of microwave energy. It has been found that a moisture content in excess of 15% and up to 50% by weight, increases tobacco expansion in the process of the invention when microwave energy is employed for heating the tobacco. Particularly when the moisture content of the tobacco is to be increased to greater than about 25% by weight, the moisturizing conditioning process is conducted at a time close to the impregnation step, for example, from several minutes to several days prior to the impregnation step, preferably less than 24 hours prior to the impregnation step. This can prevent molding of the moist tobacco during storage.
  • Expanded tobacco 54 is removed from the microwave treatment zone by conveyor 130 and passed via rotary star valve 134 , to a conventional conveying means such as a conveyor belt 58 .
  • the expanded tobacco exiting the microwave treatment zone 120 advantageously has a moisture content in the range of between about 7% and about 13% by weight.
  • the expanded tobacco can be passed to a conventional reordering treatment (not shown) and/or to a sulfur hexafluoride stripping zone; however, typically the tobacco will have a sulfur hexafluoride content of less than about 0.15% by weight so that recovery of the residual sulfur hexafluoride may be unnecessary.
  • microwave heating units Any of various commercially available microwave heating units may be employed for the microwave treatment of sulfur hexafluoride impregnated tobacco.
  • An exposure time of 9-12 seconds has been employed in a 4.5-5.5 kilowatt treatment zone having a frequency of 2375 MHz and an efficiency of about 50% to treat 1/4 to 1/2 pound per minute.
  • the microwave treatment zone can advantageously include an agitating means for agitating the tobacco during the microwave treatment to ensure that all of the tobacco is uniformly exposed to microwave energy and also to ensure that the impregnated tobacco is not excessively compressed during heating which could interfere with expansion of the tobacco.
  • Such agitation means can include, for example, the use of a microwave-transparent rotary drum within the waveguide; gas lines for fluidizing the tobacco within the waveguide or the like.
  • the power of the microwave unit will be selected depending upon the amount of tobacco being treated. Exposure times can be increased or decreased also depending upon the amount of tobacco being treated. However, a short, relatively high energy treatment is preferred to ensure maximum tobacco expansion.
  • the tobacco is treated by spraying with water and the moistened tobacco stored for a period of for example, 24 hours, the moisture will fully equilibrate through the cellular structure of the tobacco.
  • treating the tobacco with moisture in the form of steam, as illustrated in Figure 2 enhances the rate of moisture penetration into the tobacco.
  • the impregnation step of the invention can be conducted over a wide range of temperatures and pressures.
  • the time period for complete impregnation will depend, at least in part, upon the temperature and pressure employed during the impregnation step. Thus, higher temperatures and pressures tend to promote more rapid impregnation whereas lower temperatures and pressures can increase the amount of time required for impregnation.
  • an impregnation time of less than about 15 minutes will be sufficient.
  • Preferred impregnation temperatures range from about 20°C up to as high as 44°C-45°C. At these preferred temperatures, impregnation is rapid.
  • Preferred impregnation pressures range from about 1,000 to about 2,500 psi, preferably between about 1,200 psi and about 2,000 psi.
  • temperature and pressure conditions within the impregnation zone are maintained so that substantially all of the sulfur hexafluoride will be in the liquid phase.
  • Operation within the liquid phase provides substantial contact between the sulfur hexafluoride and the tobacco thereby enhancing rapid and full impregnation.
  • operation within the liquid phase is believed to increase the amount of sulfur hexafluoride absorbed by the tobacco.
  • tobacco can also be impregnated with sulfur hexafluoride in accordance with this invention by operating at temperatures and pressures wherein a portion or all of the sulfur hexafluoride is maintained in the gas phase.
  • Heating of the impregnated tobacco in order to effect expansion can be accomplished by means other than those discussed previously.
  • the impregnated tobacco can also be heated by radiant means to effect expansion.
  • the tobacco can be heated in a fluidized bed at a temperature of from 90°C up to 300°C.
  • Fluidized beds are known in the art and described for example in U.S. Patent No. 4,270,553 to Conrad et al. which is hereby incorporated herein by reference. The fluidized bed can be used with or without the added hot particles described in this patent.
  • the tobacco may be pretreated with various alcohols such as ethanol, or with other additives, for example hydrocarbons such as pentane or hexane, in order to promote better expansion.
  • alcohols such as ethanol
  • hydrocarbons such as pentane or hexane
  • the percent increase in filling capacity or percent expansion as reported in the following examples was computed by subtracting the corrected filling capacity of the unexpanded control sample from the corrected filling capacity of the expanded sample, dividing this difference by the corrected filling capacity of the unexpanded control sample and multiplying this quotient times 100.
  • Samples of tobacco cut filler were impregnated in a pressure vessel having a volume of 2 liters.
  • the pressure vessel included a thermocouple installed inside the vessel, close to the top thereof, to measure the temperature of the vessel contents and a pressure gauge for indicating the pressure in the vessel.
  • Sulfur hexafluoride was introduced into the vessel through a valve at the bottom of the vessel and removed from the vessel by two valves at the top of the vessel, by opening the valves and allowing the gas contents to escape.
  • a thermostatically controlled heating jacket was provided around the vessel for heating during the impregnation.
  • Tobacco samples having a weight of about 150 grams were impregnated using the apparatus of Example 1.
  • the tobacco consisted of the same cased blend of flue cured and burley tobaccos as used in Example 1.
  • the impregnated samples were removed from the impregnating vessel and hand carried, without refrigeration or insulation, to a microwave heating apparatus substantially as illustrated in Figure 2 except that no gas recovery system was used.
  • the average transport time to microwave processing was about 1.5 to about 2.5 minutes.
  • the waveguide or microwave treating zone had a length of about four feet.
  • the tobacco was carried on a moving belt through the waveguide to provide an exposure time of 9-12 seconds.
  • the power of the microwave was variable up to 6.0 kW maximum.
  • the power setting for the microwave apparatus was as set forth below.
  • Example 2 The procedures of Example 2 were repeated using the same types of tobacco samples, treating vessel, and microwave heating zone, but with different impregnation temperatures and pressures.
  • TABLE III Run # Impreg. Pressure (psig) Impreg. Temp. (°C) Impreg. Time (Minutes) Discharge Temp. (°C) %Moisture Initial Micro. Power kW Percent Expansion 1 400 16 15 -30 25 5 42 2 400 24 15 -23 27 5 58 3 400 20 15 -27 35 5.5 62
  • Example 2 The procedures of Example 2 were repeated using the same types of tobacco samples, treating vessel, and microwave heating zone, but with different impregnation temperatures and pressures.
  • Run #1 In Run #1 some small frozen tobacco lumps were observed and it is believed that the microwave power was insufficient to fully heat the tobacco. Additionally, it is believed that the increased moisture content of Run #3 was at least partially responsible for the increased amount of tobacco expansion observed.
  • Example 2 The procedures of Example 2 were repeated using the same types of tobacco samples, treating vessel, and microwave heating zone, but with different impregnation temperatures and pressures. TABLE V Run # Impreg. Pressure (psig) Impreg. Temp. (°C) Impreg. Time (Minutes) Discharge Temp. (°C) %Moisture Initial Micro. Power kW Percent Expansion 1 600 25 15 -10 19 4.5 38 2 600 31 15 +6 25 4.5 47
  • Example 2 The procedures of Example 2 were repeated using the same types of tobacco samples, treating vessel, and microwave heating zone but with different impregnation temperatures and pressures.
  • Example 2 The procedures of Example 2 were repeated using the same types of tobacco samples, treating vessel, and microwave heating zone, but with different impregnation temperatures and pressures.
  • Example 2 The procedures of Example 2 were repeated using the same types of tobacco samples, treating vessel, and microwave heating zone, but with different impregnation temperatures and pressures.
  • Example 2 The procedures of Example 2 were repeated using the same types of tobacco samples, treating vessel, and microwave heating zone, but with different impregnation temperatures and pressures.
  • Example 2 The procedures of Example 2 were repeated using the same types of tobacco samples, treating vessel, and microwave heating zone, but with different impregnation temperatures and pressures.
  • Example 2 The procedures of Example 2 were repeated using the same types of tobacco samples, treating vessel, and microwave heating zone, but with different impregnation temperatures and pressures. In this example, moisture contents were kept low to observe the moisture content effect in microwave expansion.
  • moisture content can have a significant impact on tobacco expansion.
  • Example 2 The procedures of Example 2 were repeated using the same types of tobacco samples, treating vessel, and microwave heating zone, but with different impregnation temperatures and pressures.
  • Example 2 The procedures of Example 2 were repeated using the same types of tobacco samples, treating vessel, and microwave heating zone, but with different impregnation temperatures and pressures.
  • Example 2 The procedures of Example 2 were repeated except that following impregnation, the sulfur hexafluoride was removed from the bottom of the vessel as a liquid and thus the temperature of the impregnated tobacco was substantially higher due to less cooling from evaporation of sulfur hexafluoride during the decompression step. The following results were obtained. TABLE XIV Run # Impreg. Pressure (psig) Impreg. Temp. (°C) Impreg. Time (Minutes) Discharge Temp. (°C) %Moisture Initial Micro. Power kW Percent Expansion 1 1700 43 7 23 35 5.5 60 2 1700 43 7 21 35 5.5 62
  • Tobacco samples were impregnated as in Example 2.
  • the tobacco samples were weighed immediately before and immediately after impregnation. The difference in weight was assumed to be due to absorbed sulfur hexafluoride.
  • Impregnation pressures were generally about 1700 psi.
  • Impregnation temperatures and time were generally about 40°C and 7 minutes, respectively.
  • the discharge temperature upon decompression of the impregnation vessel was generally between -5°C and 0°C. It was found that immediately after impregnation, the samples contained between 1.2% and 2.8% by weight, sulfur hexafluoride.
  • the samples were allowed to stand, open to the atmosphere at 25°C for a period of 1 minute, and were then weighed again. It was found that approximately 35%-40% of the retained sulfur hexafluoride had been lost to the atmosphere by evaporation. Nevertheless, substantial expansion could be obtained by heating the impregnated samples of tobacco.
  • Example 2 The impregnation procedures of Example 2 were repeated and the entire batch of impregnated tobacco was heated in a fluidized bed.
  • the impregnation pressure was 1,700 psi.
  • the impregnation temperature and time were 39°C and 9 minutes, respectively.
  • the initial moisture of the sample was 35% by weight.
  • Hot air having a temperature of 90°C was employed as the fluidizing medium and the tobacco was heated for about 50 seconds. Following heat treatment, the tobacco had obtained a 52% increase in filling capacity.
  • the expanded tobacco was recovered with a moisture content of about 12% by weight.

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  • Manufacture Of Tobacco Products (AREA)
EP19900306602 1989-06-19 1990-06-18 Procédé d'expansion du tabac Withdrawn EP0404473A3 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US36758989A 1989-06-19 1989-06-19
US367589 1989-06-19
US459007 1989-12-29
US07/459,007 US5031644A (en) 1989-12-29 1989-12-29 Tobacco expansion process and product

Publications (2)

Publication Number Publication Date
EP0404473A2 true EP0404473A2 (fr) 1990-12-27
EP0404473A3 EP0404473A3 (fr) 1991-05-15

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EP19900306602 Withdrawn EP0404473A3 (fr) 1989-06-19 1990-06-18 Procédé d'expansion du tabac

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EP (1) EP0404473A3 (fr)
JP (1) JPH0330660A (fr)
KR (1) KR910000049A (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0754411A2 (fr) * 1995-07-10 1997-01-22 R.J. Reynolds Tobacco Company Procédé et dispositif pour la préparation et expansion de quantitées du tabac
CN102613687A (zh) * 2012-04-23 2012-08-01 四川宏普微波科技有限公司 一种采用气体热媒的微波膨胀烟梗的方法
US8931491B2 (en) 2008-10-22 2015-01-13 British American Tobacco (Germany) Gmbh Extractive tobacco material extrusion

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2106252A5 (fr) * 1970-09-02 1972-04-28 Hag Ag
FR2259546A1 (fr) * 1974-02-05 1975-08-29 Airco Inc
GB2018565A (en) * 1978-03-29 1979-10-24 Philip Morris Inc Novel tobacco product and improved process for the expansion of tobacco
USRE32013E (en) * 1974-02-12 1985-10-29 Philip Morris, Inc. Expanding tobacco
EP0286423A2 (fr) * 1987-04-10 1988-10-12 R.J. Reynolds Tobacco Company Procédé et appareil d'expansion du tabac

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2106252A5 (fr) * 1970-09-02 1972-04-28 Hag Ag
FR2259546A1 (fr) * 1974-02-05 1975-08-29 Airco Inc
USRE32013E (en) * 1974-02-12 1985-10-29 Philip Morris, Inc. Expanding tobacco
GB2018565A (en) * 1978-03-29 1979-10-24 Philip Morris Inc Novel tobacco product and improved process for the expansion of tobacco
EP0286423A2 (fr) * 1987-04-10 1988-10-12 R.J. Reynolds Tobacco Company Procédé et appareil d'expansion du tabac

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
WPIL FILE SUPPLIER, AN=88-287575, Derwent Publications Ltd, London, GB; & EP-A-286 423 (REYNOLDS) 10-12-1988 *

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0754411A2 (fr) * 1995-07-10 1997-01-22 R.J. Reynolds Tobacco Company Procédé et dispositif pour la préparation et expansion de quantitées du tabac
EP0754411A3 (fr) * 1995-07-10 1998-07-08 R.J. Reynolds Tobacco Company Procédé et dispositif pour la préparation et expansion de quantitées du tabac
AU697870B2 (en) * 1995-07-10 1998-10-22 R.J. Reynolds Tobacco Company Process and apparatus for tobacco batch preparation and expansion
US8931491B2 (en) 2008-10-22 2015-01-13 British American Tobacco (Germany) Gmbh Extractive tobacco material extrusion
US9101164B2 (en) 2008-10-22 2015-08-11 British American Tobacco (Germany) Gmbh Extractive tobacco material extrusion
CN102613687A (zh) * 2012-04-23 2012-08-01 四川宏普微波科技有限公司 一种采用气体热媒的微波膨胀烟梗的方法
CN102613687B (zh) * 2012-04-23 2014-03-12 四川宏普微波科技有限公司 一种采用气体热媒的微波膨胀烟梗的方法

Also Published As

Publication number Publication date
EP0404473A3 (fr) 1991-05-15
KR910000049A (ko) 1991-01-29
JPH0330660A (ja) 1991-02-08

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