FI65537B - FOERFARANDE FOER EXPANDERING AV TOBAK - Google Patents

Description

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(32) (33) (31) PrrdMtr «tuolkMi —Begird prlortttt 29.03.78 29.03.78 USA (US) 891 ^ 68, 891290 (71) Philip Morris Incorporated, 100 Park Avenue, New York, New York 10017, USA ( US) (72) Roger Z. de la Burde, Powhatan, Virginia, Patrick E. Aument, Hopewell, Virginia, Francis V. Utsch, Chester, Virginia, USA (US) (7k) Oy Kolster Ab (5! ») Method for expanding tobacco - Förfarande för expandering av tobak

The invention relates to a method for expanding tobacco. Various methods have been proposed for inflating tobacco. For example, the tobacco is contacted with a gas at a pressure somewhat higher than atmospheric pressure, followed by a drop in pressure, which causes the tobacco cells to swell, increasing the volume of the treated tobacco. Other methods that have been used or proposed have involved treating the tobacco with various liquids, such as water or relatively volatile organic liquids, to impregnate the tobacco, followed by removal of the liquids to expand the tobacco. In addition, methods have been proposed in which tobacco is treated with solids which, when heated, decompose to produce gases that swell the tobacco. Also described are methods in which tobacco is treated with gaseous liquids, such as carbon dioxide-containing water, under pressure to combine the gas with the tobacco, and when the tobacco thus impregnated is heated or the pressure applied to it is reduced, 65537 tobacco expands. Methods for expanding tobacco have also been developed, comprising treating tobacco with gases, the gases reacting to form solid chemical reaction products within the tobacco, which then decompose under the action of heat to produce gases inside the tobacco which cause the tobacco to expand upon release. In more detail, U.S. Patent No. 1,789,435 describes a method and apparatus for increasing the volume of tobacco to fill the weight loss caused by drying a tobacco leaf. To achieve this goal, dried and air-conditioned tobacco is contacted with a gas, which may be air, carbon dioxide or steam, e.g.

At a pressure of 138 kPa and the pressure is then lowered, causing the tobacco to tend to swell. The patent states that the volume of tobacco can be increased by about 5 to 15% by this method.

It is also known that tobacco can be expanded using a high frequency generator, but that there are limitations in the degree of expansion that can be achieved without affecting the quality of the tobacco.

U.S. Patent No. 2,596,183 discloses a method of increasing the volume of stripped tobacco by adding excess water to the tobacco to cause it to swell and then heating the moisture-containing tobacco, whereby the moisture evaporates and the resulting moisture vapor causes the tobacco to swell.

U.S. Patent Nos. 3,409,022, 3,409,023, 3,409,027 and 3,409,028 describe various methods for improving the utilization of tobacco stalks for use in a tobacco product by subjecting the stalks to expansion processes using various types of heat treatment or microwave energy.

U.S. Patent 3,425,425 relates to the use of carbohydrates to improve the swelling of tobacco stems. In said method, tobacco stems are dissolved in an aqueous solution of carbohydrates and then heated to swell the stems. The carbohydrate solution may also contain organic acids and / or certain salts which are used to improve the aroma and burning properties of the stalks.

P.S. Meeyer's article, "Tobacco Reporter", November 1969, describes and outlines methods of expanding tobacco or studies for expanding and treating tobacco 3 65537 with the aim of reducing costs and also as a means of reducing the "tar" content by reducing the amount of smoke. This article describes the expansion of tobacco by various methods, such as using halogenated hydrocarbons, low pressure, or working in a vacuum, or high-pressure steam treatment, which causes the leaf to expand from inside the cell when the external pressure is suddenly lowered. This article also mentions lyophilized tobacco, which can also be used to increase volume.

Since the publication of the above-mentioned article in Tobacco Reporter, numerous methods of tobacco expansion (including those mentioned in the article) have been described in patents and / or published patent applications. For example, U.S. Patent Nos. 3,524,452 and 3,524,451 disclose tobacco using a volatile organic liquid. such as a halogenated hydrocarbon.

U.S. Patent 3,734,104 describes a method of expanding tobacco stems.

U.S. Patent No. 3,710,802 and GB Patent No. 1,893,735 relate to freeze-drying methods for expanding tobacco.

ZA Patent Applications 70/8291 and 70/8282 relate to the expansion of tobacco using chemical compounds that decompose to form a gas, or using inert gas solutions that are pressurized to keep the gas in solution until it saturates the tobacco.

U.S. Patent No. 3,771,533 discloses treating tobacco with carbon dioxide and ammonia gas, wherein the tobacco is impregnated with these gases and ammonium carbonate is formed in situ. The ammonium carbonate is then decomposed by heating to release gases inside the tobacco cells and cause the tobacco to swell.

Despite all the advances in the field described above, no completely satisfactory method has been found. The difficulty with these various previous proposals for expanding tobacco is that in many cases the volume increase is only modest or, at best, only moderate. Freeze-drying methods, for example, have the disadvantage that they require labor and expensive equipment and very substantial operating costs. As for the use of thermal energy, infrared or radiation microwave energy to swell the tobacco feed path, there is a difficulty in that while the stalks respond to these heat treatments, the tobacco leaf has generally not been found to respond effectively to this type of process.

The use of special blowing agents, for example halogenated hydrocarbons, as mentioned in Meyer's paper on blowing tobacco, is also not entirely satisfactory, as some of the substances used are not always desired as additives. In addition, the introduction of foreign substances into the tobacco, in significant concentrations, causes problems at the end of the treatment to remove the blowing agent in order to avoid affecting the smoke aroma and other properties that could occur due to the use of foreign substances or combustion of treated tobacco.

Furthermore, the use of carbonated water has not been found to be effective.

While the process using ammonia and carbon dioxide gases is an improvement over the previously described processes, it is not entirely satisfactory in some circumstances in that unwanted salt deposition can occur during the process.

Carbon dioxide has been used in the food industry as a refrigerant and has recently been proposed as an extractant for food spices. It is also described in DE-A-2 142 205 for use in either gaseous or liquid form for the extraction of aromatic substances from tobacco. However, the use of gaseous carbon dioxide in the expansion has not been proposed.

GB 1 375 420 and 1 375 820 relate to processes in which nitric oxide and sulfur oxide are used as blowing agents. However, these substances have some disadvantages when impregnating tobacco. Nitric oxide is highly flammable and has a physiological effect, which is detrimental to the treatment in question. substance in large quantities. Sulfur dioxide also has disadvantageous properties when treated in large quantities, and in particular has the disadvantage that even small residues must be carefully removed from the tobacco after impregnation.

A process using liquid carbon dioxide has been found to overcome many of the disadvantages of the above processes.

65537

The expansion of tobacco using liquid carbon dioxide is described in GB Patents 1,444,309 and 1,484,536.

The method comprises the steps of (1) contacting the tobacco with liquid carbon dioxide to impregnate the tobacco with liquid carbon dioxide, (2) subjecting the tobacco impregnated with liquid carbon dioxide to conditions in which the liquid carbon dioxide is converted to solid carbon dioxide, and (3) the solid carbon dioxide is then converted to solid carbon dioxide. evaporates causing the tobacco to swell.

However, impregnation with liquid requires the use of complex equipment, as both liquid and gas removal must be possible and a device for indicating the amount of liquid is required. Liquid-impregnated tobacco traps more carbon dioxide as it exits the impregnator and leads to an increase in the heat load of the expansion system and high carbon dioxide losses. The most important point is that impregnation with liquid requires a long drainage time to remove unabsorbed liquid. However, as the pressure decreases, so much solidifying liquid remains that the product exiting the impregnator clumps. In order to transfer the impregnated tobacco to the expansion system, it is necessary to break up the clumps formed.

In a previous study by the applicant with gaseous CCl 4 at a pressure of about 690 kPa (100 psia), it had been found that only small amounts of carbon dioxide gas could be combined with tobacco and kept there long enough when heated and expanded. Thus, no substantial improvement over the prior art was observed and gaseous CCl 4 was believed to be less effective as a blowing agent than the liquid carbon dioxide used in the blowing processes of the aforementioned GB Patents 1,444,309 and 1,484,536.

It has now been found that gaseous carbon dioxide can be combined with tobacco in such a way that gaseous carbon dioxide remains in the tobacco, resulting in a product which can then be expanded.

The invention relates to a method of expanding tobacco, which method is characterized by contacting the tobacco with carbon dioxide gas at an overpressure of at least 1.7 MPa (250 psig) and at a temperature sufficient to keep substantially all of the carbon dioxide gaseous and for a time sufficient to 65537 tobacco. to saturate with carbon dioxide gas, after which the pressure is reduced and the impregnated tobacco is heated to release carbon dioxide and expand the tobacco.

With the method according to the invention, gaseous carbon dioxide can be combined with tobacco so that the amount of carbon dioxide in the tobacco is even more than 3%, and when the product obtained is expanded, the cylinder volume increases by at least about 50%. Impregnated tobacco contains at least 1 part by weight of gaseous carbon dioxide per 100 parts of tobacco.

The process can be carried out by placing the tobacco, which generally has a moisture content of about 5 to 35% by weight, in a pressure vessel or similar sealable space. Carbon dioxide gas is passed through to purge the vessel. The carbon dioxide pressure is then increased to an overpressure of at least about 1.7 to 7.3 MPa (250-1057 psig) and preferably to an overpressure of about 2.8 to 5.5 MPa (400 to 800 psig). The tobacco is maintained under such pressure under conditions in which the carbon dioxide is predominantly in the form of a gas for about 0.25 to 30 minutes to saturate the tobacco with carbon dioxide. The pressure is then lowered for 1-1800 seconds, preferably 10-120 seconds, preferably to atmospheric pressure to give the tobacco a product having at least 1% by weight of gaseous carbon dioxide, based on the weight of the tobacco. The resulting carbon dioxide-containing tobacco can then be heated in the same vessel, but is preferably quickly transferred to a separate zone where it is heated with gas for about 1 to 10 minutes. At 100-370 ° C at or near atmospheric pressure to expand tobacco.

Prior to depressurization, the tobacco / CO 2 system can be cooled, e.g., by circulating coolant through the jacket surrounding the chamber, to a temperature close to, but not below -23 ° C, the carbon dioxide saturation temperature. As an alternative to the use of a cooling jacket, CC 2 gas can be made to flow through the system by discharging part of the CO 2 gas, keeping the CO 2 gas supply so that there is no drop in system pressure due to the discharge. The conditions created by the cooling are such that the carbon dioxide at the prevailing temperature and pressure remains mainly in the gaseous state and, in addition, such that the carbon dioxide, after a rapid drop in pressure, is converted into partially condensed tobacco inside the tobacco. Such conditions can be defined as keeping the enthalpy of carbon dioxide below 330,000 J / kg / (140 BTU / lb). In this way, a significantly higher amount of carbon dioxide is present in the tobacco at the beginning of the expansion phase, compared to the case where no cooling is used before depressurization, whereby the carbon dioxide, at a higher enthalpy, remains mainly in the gas phase throughout. Another way to lower the enthalpy of the system and thus increase the carbon dioxide content of the tobacco is to introduce more CCl 2 gas through the system during depressurization.

If desired, the carbon dioxide content of the tobacco can be increased by pre-cooling or pre-cooling the tobacco prior to the impregnation step, thereby reducing the enthalpy of the system.

In the method according to the invention, either whole dried tobacco leaves, tobacco in cut or shredded form, or selected parts of tobacco, such as tobacco stems or reconstituted tobacco, can be used. The particle size of the tobacco to be treated in the comminuted form may correspond to a screen number of about 10 to 100 "mesh", but is preferably not less than about 30 "mesh".

The moisture content of the tobacco to be treated is normal, i.e. n.

5-35% by weight. However, it is preferred that the tobacco have a moisture content of at least 8% by weight and at most about 22%. As used herein, the percentage of moisture can be considered equivalent to oven volatiles (OV) because no more than about 0.9% by weight of the tobacco contains volatiles other than water. The method for determining the volatiles in the furnace is given below.

The tobacco is usually placed in a pressure vessel, which is described in more detail below. It can be placed, for example, on a screen cylinder or on a platform placed inside the container.

The pressure vessel containing the tobacco can then be blown clean with carbon dioxide gas. The benefit of blowing is the removal of gases that could interfere with the carbon capture process and / or that could interfere with the absorption of gaseous carbon dioxide. As an alternative to blowing with carbon dioxide gas, the vessel can be evacuated before the carbon dioxide gas is introduced.

Either with or without the use of pre-blowing or vacuum cleaning of the container, the air is fed to the container under conditions in which the pressure of the carbon dioxide gas in the container increases, the tobacco in the container preferably being at a temperature of about -10 to 60 ° C. and the overpressure in the vessel is at least 1.7 MPa (250 psig), preferably 2.8-5.5 MPa (400-800 psig). The tobacco is maintained under conditions of carbon dioxide overpressure of at least 1.7 MPa (250 psig) and corresponding to those prevailing above and to the right of the saturated steam curve shown in Figure 1, from about 15 seconds to about 30 minutes. The pressure is then reduced over a period of 1 to about 800 seconds, preferably 10 to 120 seconds, so that at no point does the temperature fall below the carbon dioxide saturation temperature at the same time and the tobacco is brought below a temperature of about 10 ° C and atmospheric pressure or pressure. .

When the impregnation step is performed under non-cooling conditions, a product is obtained with at least one part of carbon dioxide gas per 100 parts of tobacco. By this is meant that at least one part of the carbon dioxide gas per 100 parts of tobacco is in some way associated with the tobacco, chemically and / or physically, for example as absorbed by the tobacco. The product may contain as much as 3 parts or more of gaseous carbon dioxide. This can be achieved without the addition of adsorbents or the like. Absorbents, absorbents, etc. may be present, however, it is preferred that they be absent because the process is effective without them and could introduce undesirable elements into the smoke or interfere with the effective release of carbon dioxide.

When the impregnation step is performed under cooling conditions, a product is formed with as much as 3 parts or more of gaseous carbon dioxide per 100 parts of tobacco.

The carbon dioxide used in the process is generally obtained from a storage vessel in which it is maintained at a pressure of about 1.5-2.1 MPa (215-305 psig) and a temperature between -29 ° C and -16 ° C. The carbon dioxide can be introduced into the pressure vessel at a pressure of 1.5-2.2 MPa (215-320 psig) and a temperature between -29 ° C and -14 ° C, but is preferably brought above -23 ° by suitable methods. C and pressures greater than 1.7 MPa (250 psig) prior to introduction into the pressure vessel. After impregnation, carbon dioxide is removed from the tobacco by heating. The heating could be performed using hot surfaces, hot air flow or a mixture of gases and vapors, or by exposing the impregnated tobacco to e.g. microwave energy or infrared radiation. It has been found that the use of a gas combination containing at least 50% (by weight) of steam, and preferably more than 80% (by weight) of steam, gives very good results. A suitable way to inflate the carbon dioxide-containing tobacco is to introduce it into a heated gas stream, such as a superheated steam stream, or into a vortex air stream maintained, for example, at a temperature of about 150 to 260 ° C for about 1 second to 10 minutes. Impregnated tobacco can also be heated by placing it on a moving belt and subjecting it to infrared heating, placing it in a cyclone dryer, contacting it with steam superheated in the tower, or a mixture of steam and air and the like. During heating, the temperature should not rise above about 370 ° C, and should preferably be about 100 to 300 ° C, and most preferably 150 to 260 ° C when the heating takes place at atmospheric pressure.

As is well known when handling organic materials, overheating can cause damage, first to color, such as excessive darkening, and finally to charring. Thus, to avoid unwanted damage during the heating step, non-impregnated tobacco should be heated at high temperatures, e.g., 370 ° C, for more than 1-2 seconds.

One way to swell tobacco cells is to use the irradiation methods described in both U.S. Patent Nos. 3,409,022 and 3,409,027. In this process, the tobacco never reaches a temperature above about 140 ° C and is cooled by the rapid evolution of gases. The presence of steam during heating helps to obtain optimal results.

In one system, which is generally preferred, a dispersion dryer is used, for example one to which steam is fed either alone or in combination with air. One example of such a dryer is the Proctor & Schwarts-PB splitting dryer, hereinafter also referred to as a tower. The temperature in the dryer can be about 120 to 370 ° C and the contact time in the dryer is about 1 to 10 seconds. Generally, a contact time of 1 to 6 seconds is used when the hot gas temperature is 260 to 315 ° C or somewhat higher. As stated above, other known types of heating devices may be used as long as they are capable of causing the impregnated tobacco to swell without undue darkening. The presence of 20% or more of steam, calculated on the total hot gas combination, helps to obtain the best expansion; a high proportion of steam (e.g. more than 80% by volume) is preferred.

In the following, the invention will be considered with reference to the figures.

Figure 1 is a standard phase diagram of a carbon dioxide-tobacco system with CO2 pressure (p.s.i.a) plotted as a function of tobacco bed temperature (° F), with curves I-II-III illustrating the system now in use;

Figure 2 is a standard pressure, enthalpy diagram, with curves I-IV illustrating the present invention,

Figure 3 is a standard pressure enthalpy diagram with curves I-IV illustrating the method of the invention.

For a general description of the practice of the present invention, reference is made to Figure 1. For example, the conditions may be as shown in curve I-II-III in Figure 1. For example, tobacco with an OV (oven volatiles content) of about 12% in the form of a cut light filler is placed in a pressure vessel. withstands the desired pressure, for example 7.3 MPa (1057 psig). The vessel may be similar to the impregnation vessel described in GB Patent 1,444,309, but unlike the apparatus used therein, no apparatus is required to treat liquid CC> 2. The vessel may be blown clean with gaseous CO 2 or evacuated and pressurized with gaseous CO 2 to bring the contents to conditions (point II) where the pressure is greater than 1.7 MPa (250 psig) and the temperature is not lower than -23 ° C. The pressure is then lowered (to point III). The conditions for the whole series (as shown by curves I-II-III) are such that the carbon dioxide remains below the saturated steam curve and to the right of Figure 1.

In one embodiment of the invention, as can be seen in Figure 2, the enthalpy of CO 2 is greater than about 330,000 J / kg (140 BTU / lb 2) and the CO 2 is present in gaseous form. The vessel is held under these conditions for 0.25-30 minutes as described in Curve I-III. The pressure is then rapidly reduced, preferably in 10 to 120 seconds, preferably to atmospheric pressure, as illustrated by curve III-IV in Figure 2.

11 65537

The impregnated tobacco is transferred (preferably but not necessarily directly) to a rapid heating zone or vessel, such as the heating vessel described in the aforementioned GB Patent 1,444,309, or, for example, to an expansion tower, microwave chamber or the like.

The temperature at which the impregnated tobacco is maintained prior to the swelling or rapid heating step largely determines how long the CO 2 STAYS in the tobacco in a sufficient amount to provide the desired swelling. If there is little insulation or equipment to keep the temperature low, the transfer should take place quickly, preferably in less than a few minutes. An insulated "fluffy" container is preferably used for transfer. Additional cooling can also be provided, for example, by applying crushed or ground carbon dioxide ice or by spraying liquid nitrogen on the impregnated tobacco.

Rapid heating causes the tobacco to swell at a temperature where the tobacco is flexible and flexible, and the tobacco can swell without breaking in much the same way as when it is in a green leaf state. In this case, significant expansion takes place and a usable degree of expansion is achieved.

Reference is now made to Figure 3. Tobacco with an OV of about 12%, in the form of a cut light filler, is placed in a pressure vessel. The vessel may be similar to the impregnation vessel described in GB Patent 1,444,309, but unlike the apparatus used therein, no apparatus is required to treat liquid CO 2. The vessel may be blown clean with gaseous CCl 4 or evacuated and pressurized with CCl 2 to bring the contents to conditions where the pressure is greater than 1.7 MPa (250 psig) and the temperature is not below -23 ° C and the enthalpy is 330,000 J / kg (140 BTU / lbm) or greater, as shown in Curves I-II. The enthalpy of CC 2 is then reduced by cooling to less than about 330,000 J / kg (140 BTU / lbm) (but under temperature and pressure conditions such that CO 2 is present primarily as a gas) as shown in Curve II-III. The vessel is kept under these conditions for 0.25 to 30 minutes. The pressure is then reduced abruptly, preferably in 10 to 120 seconds, for example, to atmospheric pressure, as shown in curve III-IV.

The impregnated tobacco is then transferred (preferably but not necessarily directly) to a rapid heating zone or vessel, such as the heating vessel described in the aforementioned GB Patent 1,444,309, or, for example, to an expansion tower, microwave chamber or the like.

Rapid heating causes the tobacco to swell at a temperature where the tobacco is flexible and flexible and the tobacco can swell without breaking in much the same way as in its green leaf space. In this case, sufficient expansion takes place and a usable degree of expansion is achieved.

. The temperature at which impregnated tobacco is kept before swelling! rapid heating s phase, largely determines how long CC> 2 remains in the tobacco in an amount sufficient to effect the desired swelling. If there is little insulation or equipment to keep the temperature low, the transfer should take place quickly, preferably in less than a few minutes. An insulated "fluffy" container is preferred for transfer. Additional cooling can also be provided, such as by applying crushed or powdered carbon dioxide ice or spraying liquid nitrogen on the impregnated tobacco.

The following examples are illustrative:

Example 1 A 0.45 kg (1 lb) sample of a commercially coated light tobacco filler with an OV of 12.5% was placed in an autoclave-type pressure vessel and pressurized to 5.5 MPa (800 psig) with CCl 2 gas. was obtained from a CCl2 feed tank maintained at a CCl4 pressure at least somewhat higher than the desired saturation pressure. The temperature of the impregnation system was maintained above 30 ° C during the pressure cycle by supplying additional heat to the system, as necessary, to prevent the formation of liquid or solid CO 2 throughout the process cycle. After a contact time of 15 minutes, the enthalpy of CCl 3 gas was found to correspond to an enthalpy value of CCl 3 gas of about 330,000 J / kg (140 BTU / lb) in a pressure and temperature impregnator. The pressure was dropped out in about 30 seconds, after which the temperature of the tobacco was found to be 2.2 ° C. The weight gain of the impregnated sample was 2.0% due to the gaseous CCl 2 it contained. The impregnated material was then subjected, within 5 minutes, to heating in a 7.6 cm (3-inch) diameter tobacco expansion column by contacting it with superheated steam at 288 ° C and 43 m / s (140 ft / s) for about 4 seconds. . The OV of the product leaving the expansion column was 13,65537 2.1%. The product was equilibrated under standard conditions, 23.9 ° C and 60% relative humidity for 18 hours. The filling capacity of the equilibrated product was measured by the standardized cylinder capacity (CV) ** test described later in this specification and was 74 ml / 10 g with an OV of 11.2%. This gave a corrected CV (= CCV) of 76 ml / 10 g when the OV was 11%. The unexpanded comparison cylinder volume was found to be 36 ml / 10 g. The filling capacity of the sample was thus increased by 111% after treatment as measured by the CV method.

Example 2

A series of light tobacco samples were treated as in Example 1 under conditions that produced gaseous CO2 but did not produce substantially liquid or solid CO2. The OV of the fed tobacco ranged from 9% to 14.6%. The conditions in each test and the test results are shown in Table I. When no value is given for a variable in the table, the value is the same as in Example 1.

Table I

Expansion of the filler with gaseous CO 2

Test No. 2 _3 OV of feed tobacco 9.0% 10.3% 14.6% impregnating agent, (psig) MPa (800) 5.5 (800) 5.5 (800) 5.5 temperature before discharge, ° C 31.7 31.7 32.2 Enthalpy of CO2 before discharge, (BTU / lb) J / kg (143) 330000 (143) 330000 (143) 330000 temperature of the tobacco after discharge, ° C -20.0 -22.8 +2.8% retention of CO2 in the tobacco 2.9 2.4 1.5 OV after expansion of the product 1.7% 1.8% 3.2% CV of the rearranged product 62 94 74 OV of the rearranged product 11.6 10.3 11.3 corrected CV when OV is 11% 66 88 76 increase in filling capacity% 83 144 1 1 1 14 05537

Example 3

A series of light tobacco samples were treated as in Example 1 under conditions where gaseous CO2 was formed but no substantially liquid or solid CO 2 was formed. * Retention time was varied. The conditions and test results are shown in Table II. When no value is shown for any variable in the table, the value is the same as in Example 1.

Table II

Expansion of the filler with gaseous CO2

Test no 3_ £ 5_ feed tobacco OV 14.2% 14.4% 15.3% saturation pressure, (psig) MPa (800) 5.5 (800) 5.5 (800) 5.5 retention time, minutes 1 2 20 CO2 temperature before discharge - kua, ° C 58.9 30.0 35.6 enthalpy of CO2 before discharge, (BTU / lb) J / kg (160) 370000 (142) 330000 (144) 335000 temperature of tobacco after discharge ° C 8.3 -5.6 4.4 CC> 2 abstinence from tobacco 2.0 2.6 1.5 after expansion of product OV 2.2% 2.0 3.8 CV of rearranged product 71.2 74.0 76.2 OV of rearranged product OV 11.1 11.6 11.6 corrected CV when OV is 11% 72 78 80% increase in filling capacity 100 117 122

Example 4

A series of light tobacco samples were treated as in Example 1 under conditions where no liquid or solid CO 2 was expected to form. The saturation pressure was varied. The test results are shown in Table III. When no value is assigned to a variable in the table, the value is the same as in Example 1.

15 65537

Table XII

Expansion of the filler with gaseous CC ^ sHa%

Tests no 6 T_ 9. 1_0 1J.

OV 14.5 13.6 10.3 16.1 13.2 13.3 impregnation pressure of fed tobacco, (psig) MPa (300) 2.07 (400) 2.76 (500) 3.45 (600) 4.14 (700) 4.83 (800) 5.5 retention time, min. 15 15 15 25 15 15 CC ^ temperature before discharge, ° C -11.7 NA 20.6 20.6 19.4 53.9 (enthalpy of X> 2 before discharge, (BTU / lb) kJAg (143) 333 NA (150) 3.49 (145) 337 (142) 330 (155) 361 temperature of tobacco after discharge ° C -13.9 NA 3.3 -5.6 -16.7 20.6 CV of product after folding 2.2 1.9 2.1 2.1 3.4 2.7 CV of rearranged product 69 69 59 75 74 60 product CV 10.7 11.5 11.7 11.4 11.5 11.6 corrected CV when CV is 11% 66 69 64 79 77 65 increase in filling capacity 83 92 78 119 114 81

Example 5 A 0.45 kg (1 lb) sample of commercial packaged filling tobacco with an OV of 11.1% was placed in an FS-3 pressure vessel and pressurized to 5.5 MPa (800 psig) with CO 2 gas. as in the method of Example 1. The temperature of the impregnation system was cooled by circulating the cooling solution through the jacket surrounding the impregnation vessel until the CO 2 gas in the impregnator had cooled close to its impregnation temperature. After a contact time of 15 minutes, the enthalpy value of the CC 2 gas was found to correspond to an enthalpy value of CC> 2 “gas of about 300 kJ / kg (130 BTU / lb) in the impregnator of the pressure and temperature conditions. Although some condensation of CO 2 was likely to occur within the vessel, CO 2 was primarily a gas. The pressure was reduced by calculating approx.

In 30 seconds, after which the tobacco temperature was found to be -37.8 °. The weight gain of the saturated sample was about 3.5% due to CO2. This impregnated material was then heated as in Example 1. The OV of the product leaving the expansion tower was 1.9%. The CV of the balanced product was 90.6 while the OV was 10.8%. This corresponds to a CCV of 89, a 147% increase in filling capacity compared to the unexpanded control (36 ml / 10 g).

Example 6

A series of light tobacco samples were treated as in Example 5 under conditions in which the CO 2 gas was cooled to near saturation before the pressure dropped, at three different pressures. The conditions and test results are shown in Table IV. When no value is assigned to a variable in the table, the value is the same as in Example 1.

Table IV

Expansion of the filler with gaseous CO2

Test No. 12 13 14 OV of the fed tobacco 9.5% 10.8 12.1 saturation pressure, (psig) MPa (800) 5.5 (600) 4.1 (500) 3.4 retention time, minutes 15 15 20 CO2: n temperature before discharge, ° C kJ / kg 19.4 7.2 2.2 enthalpy of CO2 before discharge, (BTU / lb) kJ / kg (129) 300 (139) 323 (139) 323 tobacco temperature after discharge , ° C -38.9 -27.8 -18.3 CO2 retention in tobacco 3.7 2.6 2.4 Product OV after swelling 1.3% 1.4 1.9 Re-order product CV 89 88 71 17 65537

Table IV continues The expansion of the filler with gaseous CCl 4

Test No. 12 13 14 OV of the rearranged product OV 10.5 10.9 11.9 corrected CV when OV is 11% 85 87 78 increase in filling capacity,% 136 142 117

Example 7

The procedure of Example 5 was repeated using packaged light Burley tobacco. The CV of the equilibrated expanded product was found to be 92.4 when the OV was 10.1%, i.e. an increase of about 100% compared to the unexpanded control.

Example 8

The procedure of Example 5 was repeated using a tobacco blend commonly used in the manufacture of cigarettes. The CV of the product was found to be 78.1 when the OV was 11.1%, i.e. the increase was n.

105% compared to unexpanded comparison.

Example 9 A 0.45 kg (1 lb sample sample of packaged light tobacco was treated as in Example 1 and found to have a CCV of 81. This product was blended with 25% of a regular tobacco blend. Cigarettes were smoked and found to have the desired taste and aroma; acceptable.

Example 10 A 5.9 kg (13 lb) sample of light tobacco in a package was treated as in Example 5. The CCV of the product was found to be 78.

Example 11 A 2.3 kg (5 lb) sample of packaged light tobacco was impregnated as in Example 5 but then heated on a static mattress using 149 ° C steam for a 5 minute alt. The CV of the balanced product was found to be 85.

Example 12

A series of experiments were performed following the procedure of Example 5 and the experiments gave cylinder volume results of 80, 80, 80, 18 65537 79, 84, 78, 79, 78 and 79, respectively. «This gives an average CV of 80 for these nine experiments, i.e. a 121% increase in filling capacity. to an untreated control.

Example 13

A series of three experiments were performed according to the method of Example 5, except that the fed tobacco was precooled to just below -20 ° C prior to contacting the tobacco with pressurized CO 2 gas. The CV results of the rearranged product under these conditions were found to be 92, 92, and 87, respectively. This yielded an average increase in filling capacity of 151% compared to the untreated control.

Example 14

Two sets of experiments were performed in the same manner as in Example 1. However, the conditions were as shown in Table V, with a retention period of 10 minutes, and the column conditions were: 7.6 cm (3-inch) column at 320 ° C (600 ° F), 100 with% steam. Set No. 2 was treated under similar conditions as Set No. 1.

The results of each of these series of experiments are given in Table V together with the results for an unexpanded control sample as well as for a control sample expanded without air (^ treatment: 65537 19

Table V

Series no. 1 Series no. 2% Rearranged% Rearranged done

Pressure (psig) MPa OV CV / OV CCV OV CV / OV CCV

comparison 11.8 36.8 / 12.6 - - - expansion comparison - - - 1.9 64.6 / 10.9 (250) 1.7 2.5 72.8 / 10.8 71.2 1.5 73.8 / 10.8 72.3 (300) 2.1 2.8 76.3 / 10.8 74.9 1.2 81.4 / 10.7 78.9 (325) ) 2.24 2.6 77.2 / 10.8 75.9 1.2 79.6 / 10.7 77.5 (350) 2.24 2.3 78.4 / 11.0 78.4 1.2 77.3 / 11.2 78.5 (375) 2.59 2.4 80.6 / 11.1 81.0 1.4 78.7 / 11.1 79.6 (400) 2 , 8 2.6 78.5 / 11.2 79.9 1.4 82.0 / 11.1 85.6 (800) 5.5 2.8 92.0 / 11.2 93.3 1.5 97.6 / 11.1-98.0

It is observed that pressures of 1.7-5.5 MPA (250-800 psig) gave excellent expansion compared to the control samples.

The following experiments were also performed:

Test 1

The impregnation procedure of Example 11 was repeated, but the impregnated material was simply allowed to warm to room temperature and not subjected to column expansion. No increase was observed in the CV of the obtained product, but perhaps a slight decrease compared to the untreated control.

Test 2

The comparison between impregnations with gaseous and liquid CCl 4 was performed as follows.

1. Liquid CO 2 ~ 1/4 kg (3 pounds) of commercial light filler tobacco (OV 12.7%) in a package was impregnated with liquid CO 2 in 5.5 MPa (800 psig), cooled to 19.6 ° C and allowed to stand 15 minutes later, excess liquid was drained off and the pressure was lowered. The 23% weight gain was considered to be due to CO 2 sampling. The substance was somewhat agglomerated due to the large amount of CO2 retained.

2. Gaseous CO2 ~ 1.4 kg (3 pounds) of commercial light filler tobacco (OV 13.3%) in a package was pressurized with 20,65537 gaseous CO2 to 5.5 MPa (800 psig) and 19.6 ° C For 15 minutes. The pressure was then lowered. The 3% weight gain was due to CO2 uptake. The substance was free flowing and easy to handle.

Each sample was treated on a 10 cm (4 inch) diameter tobacco expansion column and the samples were equilibrated and their cylinder volume was measured. The CCV of the liquid-saturated samples was found to be 79 and the CCV of the comparable CO2-saturated sample was found to be 82.

Test 3

A series of experiments were performed in the range of saturation pressure (0.14, 0.28, 0.4, 0.55, 0.69, 1.4, 2.1, 2.8, 4.1 and 5.5 MPa (20, 40, 60, 80, 100, 200, 300, 400, 600 and 800 psig) using a 10 minute touch sheet, following the model of Example 1, and swelling occurred on a column at a vapor temperature of 316 ° C. These experiments were performed in conjunction with an unexpanded control as well as a control not had been exposed to CO2 under the conditions and results shown in Table VI.

Table VI

Pressure (psig) MPa OV% CV CV CCV

comparison 13.6 30.8 13.3 33.2 expanded reference sample 2.9 49.3 12.2 50.1 (20 0.14 2.9 55.7 11.8 57.2 (40) 0.28 2.4 54.3 11.9 56.3 (60) 0.41 2.0 57.7 11.6 58.2 (80) 0.55 2.5 57.7 11.7 58.7 (100) 0.69 2.6 55.7 11.7 56.7 (200) 1.4 2.3 56.4 11.7 57.4 (300) 2.1 2.7 55.0 11.8 56.5 (400) 2.8 1.9 65.9 11.5 68.9 (600) 4.1 1.8 75.9 11.6 80.7 (800) ) 5.5 1.8 84.4 11.5 88.4

Table VI shows that some expansion occurs at lower pressures, but pressures of about 2.8 MPa (400 psig) are necessary to reach production targets. However, from Example 14, 21,65537, it is found that a pressure of 1.7 hPa (250 psig) can be effective to provide a satisfactory degree of expansion.

The terms "cylinder capacity" and "corrected cylinder volume" are units for measuring the degree of expansion of tobacco. The term "oven volatiles" or "oven volatiles" is a unit for measuring the moisture content (or% moisture) of tobacco in tobacco. The values are determined as follows:

Cylinder capacity (CV) Filling tobacco weighing 10,000 g is placed in a 3.358 cm diameter cylinder and compressed with a 3.335 cm diameter piston for 5 minutes. The volume of filler obtained is expressed in terms of cylinder volume. This test is performed under standard ambient conditions at 23.9 ° C and 60% relative humidity: usually, unless otherwise indicated, the sample is pre-conditioned in this environment for 18 hours.

Corrected Cylinder Volume (CCV) The CV value can be set to a specific furnace volatiles concentration to facilitate comparisons.

CV = CV + F (OV p OV), where OV is the determined OV and F is the correction factor (volume / percentage) S s determined in advance for the specific type of filling tobacco in question.

Volatile matter content (OV) in the oven The sample of filled tobacco is weighed before and after 3 hours of exposure to a convection oven set at 100 ° C. The weight loss as a percentage of the initial weight is the concentration of volatiles in the furnace.

The white tobacco used in this patent application has an F value when calculating CCV of 7.6 for tobacco expanded on average with gaseous CC> 2.

Unless otherwise indicated, all percentages used herein are by weight.

Claims (8)

65537 22 A method of expanding tobacco, comprising contacting the tobacco with carbon dioxide gas at an overpressure of at least 1.7 MPa (250 psig) and at a temperature sufficient to keep substantially all of the carbon dioxide gaseous and for a time sufficient to saturate the tobacco with carbon dioxide gas; after which the pressure is reduced and the saturated tobacco is heated to release carbon dioxide and expand the tobacco. Process according to Claim 1, characterized in that, before the pressure is reduced, the impregnated tobacco is cooled to a temperature close to the impregnation temperature of carbon dioxide but not lower than -23 ° C. A method according to claim 2, characterized in that before reducing the pressure, the tobacco is cooled, at a substantially constant pressure, to bring the enthalpy of carbon dioxide to less than 330,000 J / kg (140 BTU / lb). Method according to one of Claims 1 to 3, characterized in that the pressure acting on the impregnated tobacco is substantially reduced to atmospheric pressure. Method according to one of the preceding claims, characterized in that the tobacco is contacted with carbon dioxide at an overpressure of 2.8 to 5.5 MPa (400 to 700 psig). Method according to one of the preceding claims, characterized in that the impregnated tobacco is heated to a temperature of 100 to 370 ° C. Process according to one of the preceding claims, characterized in that the impregnated tobacco contains at least 1 part by weight of carbon dioxide per 100 parts by weight of tobacco. Method according to one of the preceding claims, characterized in that the tobacco is impregnated at a temperature such that substantially all of the carbon dioxide remains gaseous when the pressure is reduced to atmospheric pressure.