CZ230793A3 - Procedure for adjusting moisture in tobacco and other organic substances - Google Patents

Abstract

A process for reordering tobacco, which results in no significant decrease in equilibrium tobacco CV or significant tobacco degradation, is provided. Tobacco to be reordered is contacted with an air stream having a relative humidity near the equilibrium conditions of the tobacco. As the ov content of the tobacco increases, the relative humidity of the air stream contacting the tobacco is increased to affect reordering of the tobacco. Also provided is a process for drying tobacco, which results in no significant change in equilibrium tobacco CV or significant tobacco degradation. Tobacco to be dried is contacted with an air stream having a relative humidity near or below the equilibrium conditions of the tobacco. As the OV content of the tobacco decreases, the relative humidity of the air stream contacting the tobacco is decreased to affect drying of the tobacco. It has been found that tobacco can be reordered or dried successfully in a continuous manner using a self-stacking spiral conveyor. <IMAGE>

Description

Procedure for the treatment of moisture in tobacco and other organic substances

Technical field

The present invention relates to methods for treating moisture, i.e., methods for increasing the moisture content and drying tobacco and other hygroscopic organic substances, such as pharmaceutical and agricultural products, including but not limited to fruits, vegetables, cereals, coffee, and tea. In particular, it relates to the use of controlled humidity air for humidifying or drying such materials.

BACKGROUND OF THE INVENTION

The need to control the moisture content of various organic materials, including tobacco, has long been recognized in the art. E.g. the moisture content of the tobacco which has been processed into a useful product has been varied many times. Each processing step, such as shaving, chopping, blending, flavoring, expanding and preparing the cigarette filler, requires a certain optimum amount of moisture that must be carefully controlled to ultimately achieve superior tobacco or other hygroscopic organic material quality. In addition, the way in which the moisture content of the tobacco is varied can have a lasting effect on the physical, chemical and subjective properties of the final product. This indicates the importance of the method and procedure used to adjust the moisture content of tobacco or other organic material.

The moisture treatment of expanded tobacco is particularly demanding. Typically, the moisture content of the tobacco coming from the expansion device is less than 6% and often less than 3%. Tobacco crumbs very easily at such low humidity. In addition, the expanded tobacco structure collapses when the moisture is treated; partially or completely returns to its unexpanded state. This degradation of the structure reduces the filler and abolishes the benefits of tobacco expansion.

Various methods are used to treat the moisture of the expanded tobacco. The most common method is to spray water by turning the tobacco over in a rotating roller. Another method uses saturated steam as the humidifying environment. Yet another method uses high humidity air that passes through a layer of tobacco moving on the web as shown in US 4,178,946.

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However, none of the above methods is fully satisfactory in the processing of expanded tobacco. Direct contact with liquid water leads to the collapse of the expanded tobacco structure. Steam humidification also causes the tobacco structure to collapse. This can be partly attributed to high temperatures in the steam environment, but also exposing the expanded tobacco to any gaseous environment in which condensation takes place, such as steam or highly saturated air, leads to the collapse of its structure.

A method which avoids these difficulties consists in leveling the moisture initially dry expanded tobacco in a chamber containing air having a moisture equilibrium with the tobacco moisture setpoint and allowing dry, expanded tobacco slowly, at 24 and 48 hours, compared to its moisture to the surrounding ^one . The progressive air velocity through the chamber is very low usually not higher than about 127 mm / s. This procedure leads to little or no deterioration in the properties of the tobacco caused by the collapse of its structure. However, the long contact times required limit the applicability of this method to the laboratory.

We have attempted to reduce the residence time required for such a balancing process by increasing the flow rate. This approach was unsuccessful because the filler content of laboratory processed tobacco could not be achieved. The size of the conveyors that must be filled with tobacco to achieve the desired long residence time, the unevenness of the moisture content of the tobacco product emanating from such devices, and the occurrence of fires in such units are described in US 4,202,357.

Using drying to control moisture in tobacco processing is as important as moistening it. When drying tobacco, physical and chemical changes can occur that affect the physical and subjective quality of the product. Therefore, the tobacco drying process is also of utmost importance.

Generally, two types of drying equipment are used in the tobacco industry. Rotary driers and belt or apron driers. Pneumatic dryers are sometimes used. A particular type of dryer was selected for the desired drying operation. For example, a belt or apron dryer is normally used for shredded tobacco, while rotary dryers are used for cut or chopped tobacco. Both rotary and belt dryers are used for drying stems.

In a belt dryer, tobacco is spread over a perforated belt and

-39133 air is drawn up or down through the tobacco web and layer. Uneven drying of the tobacco is a consequence of the channels that are created by the air flow in the layer and which allow the drying air to bypass the tobacco.

Most rotary driers in the tobacco industry are lined with steam snakes and can work as indirect or direct driers, depending on whether the heat is supplied by the jacket or whether it heats directly inside the tobacco drier. In addition, these dryers may be operated co-current when the tobacco and air streams flow in the same direction, or countercurrently as they advance in opposite directions. Rotary drying must be carefully controlled to avoid overdrying, which causes both chemical changes and unnecessary crumbling of the tobacco during rotation. In addition, with too fast drying, an impermeable layer may be formed on the surface of the tobacco to prevent diffusion of the internal moisture in the tobacco to the surface. The formation of such a layer slows the drying rate and causes uneven drying.

The use of rotary or belt dryers in the drying of tobacco can mean heat treatment that causes chemical and physical changes on the tobacco. These are not always undesirable changes and are due to the fact that water is removed from the tobacco. In typical tobacco applications, the need to dry the tobacco in a limited time determines the resulting heat treatment in a drying step. Due to this dependence of the heat treatment on drying, it is not possible to optimize the heat treatment separately from the drying, which introduced a number of limitations.

The present invention is defined by the independent claims to which reference is made.

SUMMARY OF THE INVENTION

Embodiments of the invention are characterized in that they preferably treat the moisture of hygroscopic materials such as fruits, vegetables, cereals, coffee, tea, even brittle tobacco emerging from the expansion process, and not only these can be dried and humidified without comminution. Further, the process is advantageous in that it allows the moisture content of the expanded tobacco to be treated with little or no deterioration of the tobacco structure, and allows drying of the tobacco or other suitable hygroscopic materials at approximately atmospheric pressure, eg without vacuum and at a selected temperature. The process can be controlled to an extent that conventional methods of tobacco drying do not allow.

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In a preferred embodiment of the present invention, changes in the moisture content of the tobacco or other organic material are affected by the contact of the tobacco with air having a relative humidity carefully controlled above or below the equilibrium relative humidity of the organic material with which it is in contact. The relative humidity increases or decreases continuously as needed in processing to maintain a controlled difference between the relative humidity of the organic material with which it is in contact. Careful continuous control of the relative humidity makes it possible to control the rate of moisture transfer between the organic material and its surroundings so that changes in the structure of the tobacco are minimized. The use of relative humidity as the primary driving force for moisture transfer allows independent control of heat treatment. This process can be carried out batchwise or continuously. In addition, it can be carried out without the use of rotary rollers which cause crumbling ⁴ .

BRIEF DESCRIPTION OF THE DRAWINGS

Examples of the process and preferred embodiments will be described with reference to the accompanying drawings, in which:

Giant. 1 shows the relative air humidity (RH) expressed as a percentage of the moisture content of the tobacco determined as volatile (OV);

Giant. 2 is a diagram of a laboratory apparatus for humidifying the hygroscopic organic material of the present invention using time-varying relative humidity, RH;

Giant. 3 is a view of an exemplary cut-off device for implementing the present invention in a continuous manner;

Giant. 3a is a cross-sectional view of a portion of the spiral belt magazine shown in FIG. 3, which shows the path of the air flow relative to the path of the hygroscopic organic material;

Giant. 4 is a diagram of an alternative device suitable for practicing the present invention in a continuous manner;

Giant. 5 is a flow chart illustrating the application of the present invention to humidification; and

Giant. 6 is a typical relative air humidity profile of the tobacco surface as a function of time; 3.

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This invention relates to a process for adjusting the moisture content of tobacco or other suitable hygroscopic organic materials, such as pharmaceutical and agricultural products, including, but not limited to fruits, vegetables, cereals, coffee and tea, which is characterized by ⁵ to minimizing the crushing alter physical structure, nor does it induce unwanted thermal changes in the chemical composition of the processed tobacco. More particularly, it relates to the use of controlled humidity air to moisten or dry tobacco or other suitable hygroscopic organic material. The moisture content of the tobacco or other suitable hygroscopic organic material is either increased or decreased by gradually increasing or decreasing, as appropriate, the relative humidity of the air in contact with the tobacco or other suitable hygroscopic organic material. Thus, the moisture transfer is controlled and other process characteristics such as temperature, velocity and air pressure can be optimized separately.

Two commonly used methods for characterizing the physical structure of tobacco are cylinder volume (CV) and specific volume (SV). These measurements are particularly valuable in assessing the benefits of this tobacco humidification process.

Cylinder volume (CV)

A 20g, if not expanded, and 10g, if expanded, tobacco cartridge is inserted into a 6 cm diameter densitometer cylinder. DD-60, designed by Heinf. Borgwaldt GmbH, Schnackenburgallee No.15., Postfach 54 07 02, 2000, Hamburg 54, Germany. A tobacco with a diameter of 5.6 cm and a weight of 2 kg is placed on the tobacco for 30 seconds. The resulting compressed tobacco volume is subtracted and divided by the tobacco sample weight; this gives a value of a cylindrical volume of ⁶ (CV) in cm ³ / g. This test determines the apparent volume of tobacco fill per unit weight. The test is performed under standard conditions at 23.9 ° C and 60% relative humidity; as usual, unless otherwise specified, the sample is left in this environment for 24 to 48 hours.

Specific volume (SV)

The term specific volume is a unit for measuring the volume occupied by solid objects such as tobacco, as determined by the Archimedes Extrusion Act. The specific volume of an object is determined as the reciprocal of the actual density. Specific volume

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-69133 is expressed in cm ³ / g. these measurements are suitable for both mercury porosimetry and helium pycnometry. Their results were found to correlate well with each other. When helium pycnometry is used, the weighed tobacco sample, either as it is or dried at 100 ° C for 3 hours, or even, is placed in a measuring cell in a pycnometer (Quantachrome Penta Pycnometer Model 2042-1, manufactured by Quantachrome Corporation, 5 Aerial Way, Syosset, NY). The cell is further rinsed and pressurized with helium. The volume of helium displaced by tobacco is compared to the volume of helium needed to fill the empty cell. Tobacco volume is determined by law for ideal gas behavior. In this application, unless otherwise stated, the term specific volume is used for values determined on the same sample on which the moisture content of the OV has been determined, i.e. tobacco dried for 3 hours in a circulating air drier at 100 ° C.

As used herein, moisture content may be considered identical with a content of volatile substances ⁷ OV since not more than about 0.9% of tobacco weight is volatiles other than water. Determination of volatile matter OV is a simple determination of the weight loss of tobacco by weighing after drying for three hours in a circulating oven at 100 ° C. The weight loss in percent of the original weight is the volatile matter content determined by drying in an oven, OV.

The sieve test is a method of measuring the length distribution of pieces in a sample of chopped tobacco filling. The test is often used as an indicator of the degradation of the length of the tobacco fill particles during processing. A 150 ± 20 g tobacco charge for unexpanded tobacco and 100 + 10 g for expanded tobacco is placed in a sieve shaker. The shaker uses a series of circular sieves, with a diameter of 30.5 cm (and are manufactured by WS Tyler Inc., A Subsidiary of Combustion Engineering Inc. Screenib Division, Mentor, Ohio 44060) that meet ASTM (American Society for Testing Materials ⁸ ) standards. Common mesh sizes are 6; 12; 20; and 35 mesh, corresponding to 4.2 mm; 2.11 mm; 1.27 mm; and 0.73 mm. The shaker has a stroke of about 12.5 to 25 mm and a shaking rate of about 350 ± 5 oscillations per minute. The shaker sieves the tobacco for 5 minutes and separates the sample into different size classes. Each size class is weighed and the ordered result set is the particle size distribution of the sample.

Laboratory experiments have shown that attempts to moisten tobacco quickly by exposure to air at high humidity lead to losses

-Ί9133 cylinder capacity, CV. It has also been shown that losses in the CV value occur when the tobacco is moistened or when water condenses on it. This happens when moist air comes into contact with tobacco whose temperature is below the dew point of moist air. Humidification occurs when moisture differences within the tobacco layer are created due to uneven exposure to humid air. Thus, successful humid air humidification must operate at a relatively low speed with good control of the air relative humidity, air temperature and air flow and air pressure through the tobacco bed. This is best achieved by gradually increasing the humidity of the air passing through the tobacco layer so that the tobacco is in contact with an air stream that is substantially in equilibrium with the tobacco.

Referring to FIG. 1, the ABC line is an isotherm at 23.9 ° C applicable to typical expanded tobacco. This isotherm refers to the content of volatile matter in tobacco, OV, to the relative humidity of the air that surrounds it in equilibrium at a given temperature. Thus, point B shows that at 23.9 ° C and 60% relative humidity RH, the balanced tobacco will have an equilibrium of about 11.7% volatile matter OV. The DEF line in FIG. 1 represents a typical RH profile for tobacco that has been wetted according to the present invention. The GEF line in FIG. 1 represents an alternative relative humidity profile RH, which was also found to be satisfactory. The line HF in FIG. 1 represents a typical path that represents prior art humidification methods in the equilibrium chamber at very low air speeds. Line IJ in FIG. 1 illustrates an application of the present invention for drying tobacco.

Giant. 1 shows that a humidification of tobacco having a volatile content of about 6.5% that would be in equilibrium with 30% relative humidity RH to a volatile content of 11.7% that would be in equilibrium with air with a relative humidity RH of about 60% %, can be better achieved by exposing the tobacco to air whose humidity is gradually increased from 40% to about 60% than if it were directly exposed to air of 60% RH. If the humidification is carried out under these slowly changing conditions, then the transfer of moisture from the air stream to the tobacco is relatively slow because the driving force is low and thus the expanded tobacco structure is not damaged. Humidification of the expanded tobacco without loss of CV value can be achieved by exposing the tobacco to air, the humidity of which is increased in small steps lasting for some time from 40% RH to 62% RH in about 60 minutes. This reduces the total time

-89133 required to effect humidification without significantly altering the expanded tobacco structure. Thus, the DEF and GEF lines in FIG. 1 illustrate effective embodiments of the present invention in tobacco humidification.

In FIG. 1 shows conditions close to the equilibrium segment EF and the line ABC relating to the air and tobacco flow. Significantly, for tobacco with a OV content of less than about 7%, the difference between the relative humidity of the air in equilibrium with the tobacco and the relative humidity of the humidified air stream used for humidification is great, without adversely affecting the filling capacity of the tobacco. It is also important that for tobacco with an OV content of between 7.5 and 11.5%, the humidity of the air used for humidification may be about 2 to 8% higher than the relative humidity of the air that is in equilibrium with the tobacco, with the derogation applies to tobacco with a lower content of volatile constituents, OV, without adversely affecting the filling capacity of the tobacco.

When applied to the drying of tobacco, there was no decrease in the cylindrical volume of the tobacco. This has also been found in cases where the relative humidity of the air stream used for drying was significantly less than the relative humidity of the air in equilibrium with the tobacco, i.e. the relative humidity. the relative humidity of the drying air stream was lower than the equilibrium conditions of the tobacco. Therefore, it is important that the line IJ in FIG. 1 represents only one of the many routes that can be used to dry the tobacco of the present invention.

The present invention can be applied to both batch and continuous processes. When carried out as a batch humidification process, the relative humidity of the air bypassing the tobacco increases with time to ensure the continuous growth of moisture in the tobacco. This can be achieved in a buffer chamber as shown in FIG. 2. The tobacco to be humidified is placed in a layer about 5 cm thick on trays with a sieve bottom inside the buffer chamber, so that the controlled humidity airflow can pass down the tobacco layer. Chambers that may have a volume of 0.560 to 2.250 m ³ (manufactured by Parameter Generation and Control, Inc. 1104 Old US 70, West, Black Mountain, NC 28711) have been used in a number of studies. The equalization chambers were equipped with microprocessors that allowed controlled step changes in humidity within the chamber. Tests were conducted in which dry expanded tobacco was moistened from an initial OV of 2% to a final 11% at

The use of air with a step-by-step relative humidity value from initial values between 30% and 52% to final values between 59 and 65% over a period of time between 30 and 90 minutes. Air velocities fell between about 0.254 and 1.016 m / s. The relative humidity and temperature measurements were monitored with a Thunder model 4A-1 manufactured by Thunder Scientific Corp., 623 Wyoming, SE, Albuquerque, New Mexico 87123. Air velocities were measured with an Alnor Thermo Anemometer model 8525 manufactured by Alnor Instrument Co., 7555 N. Linder Ave. Skokie, Illinois 60066. Tests in which the relative humidity was stepwise varied from baseline values as high as 52% to final values of about 62% at less than about 40 minutes yielded a moistened tobacco with a fully maintained cylindrical volume value A CV such as that obtained in a comparative experiment with similar tobacco moistened in a buffer chamber with air maintained at 60% RH and at 23.9 ° C, which passed through the tobacco at low speed for 24 to 48 hours. The step change was successful when the humid air speeds were up to 1.016 m / s and the temperature was from about 23.9 ° C to 32.2 ° C. Expanded tobacco moistened in this manner showed minimal, if any, cylindrical volume loss when compared to expanded tobacco moistened in the buffer control space.

The present invention can be carried out as a continuous process most effectively in the Frigoscandia device, which is a spiral self-leveling tobacco on the conveyor belt shown in FIG. 3. This equipment is a specially modified Model GCP 42 Spiral Freezer as supplied by Frigoscandia Food Process Systems AB of Helsingborg, Sweden. The dry tobacco to be moistened enters the unit 10 on the feeder 13, being transported by the unit 10 spirally from the bottom of the spiral magazine to the top, as shown, and exits through the tobacco outlet after moistening. The humidified air is blown downwardly through the tobacco from the humid air outlet 15 to the bottom of the spiral container 14 where it exits through the humid air outlet 16, flowing substantially countercurrently to the direction of tobacco travel, i. most of the moist air flows from the top of the inserted tobacco to the floors of the tobacco layer while the tobacco moves upward and follows the spiral movement of the entrainer. A small amount of wet air flows down the spiral path of the carrier container from top to bottom in a true countercurrent path. These types of air flows are shown in FIG. 3a. It has been found that this arrangement effectively duplicates stepped

The relative humidity changes that can be generated in the apparatus of FIG. 2.

In FIG. 3a, which is a cross-sectional view of a portion of the spiral tab of the inserted tobacco 14 shown in FIG. 3, the flow of air flow 20 and 22 relative to the path of the tobacco layer 21 is shown. As shown in FIG. 3a, directs the air flow from top to bottom over the tobacco supply in the dryer. The tobacco flow follows the bottom-up direction through the unit and is illustrated as a right-to-left movement in FIG. 3a as the tobacco advances upwardly through the spiral feeder 14. A major portion of the air 20 that is substantially upstream of the tobacco path is directed by the trays of the tobacco layer 21 and comes into contact with the tobacco immediately below, while a small portion of the air stream 22 passes through the tobacco layer. This portion of the air stream 22 may later pass through the layer of tobacco 21.

The key to a successful embodiment of the present invention, in the case of humidification, is a means to permanently increase the relative humidity of the air in contact with the tobacco, depending on the increased humidity expressed as the OV value of the tobacco. By comparing the inserted tobacco in a Frigoscandia dryer on a scroll feeder, the essence of its design permits most of the air flowing down the multiple levels of the feeder (supply on the feeder) that carry the tobacco. By introducing the tobacco from below and the air from the top of the dryer, the air and tobacco flows are substantially countercurrent. This substantially countercurrent stream provides a natural continuous gradient of RH (relative humidity) in the air in contact with the tobacco, as the air is gradually moving over the trays of the moistened tobacco. By considering the tobacco feeder speed, air and tobacco velocity, controlling the temperature and relative humidity of the humidified air, i.e., similar conditions to the batch experiments, a batch humidification experiment in a continuous configuration can be approximated. To moisten about 65.25 kg of 3% OV tobacco per hour, the following conditions were found: web speed corresponding to a residence time of about 40 to 80 minutes, inlet air temperature of about 28 to 35 ° C with an inlet relative humidity of about 61 to about 64% and an air flow rate of about 28.3 to about 70.8 m ³ per minute. When the Frigoscandia GCP 42 helical unit was used, there was no loss of CV or measurable crushing.

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Relative humidity recorders over time, such as the 29-03 RH / Temperature recorder (manufactured by Rustrak Instruments Co. E. Greenwich, RI), were connected to the Frigoscandia unit throughout the tobacco humidification period. This device showed a sustained increase in relative humidity in the spiral container with an initial relative humidity of from about 35 to 45% at the bottom of the drier, to about 62% at the top of the device where the tobacco is already fully humidified.

Giant. 6 is a typical relative humidity vs. time curve recorded by the Rustrak unit. The relative air humidity percentages of the tobacco layer versus time are shown in FIG. 6. Tobacco with an initial OV humidity of about 3% that enters the scroll unit and has been in contact with air with a relative humidity of about 43% (Point A Fig. 6). Giant. 6 shows that as the tobacco progresses through the spiral humidification unit, the relative humidity increases from about 43% to about 62% at the outlet of the unit (Point B Fig. 6). The OV tobacco is exiting the unit. The relative humidity RH entering the spiral humidifier was controlled so that the outgoing tobacco did not exhibit a significant cylinder volume loss.

In order to realize the present invention, other methods may also be used to effect a gradual change in relative air humidity, such as the unit shown in FIG. 4. According to this FIG. 4, the tobacco enters the feeder 43 at the tobacco inlet 40 and exits the tobacco outlet 41. The air of increasing humidity is introduced to blow up or down the tobacco layer 42 in several zones 44 and thus reproduce the stepped moisture effect in the apparatus of FIG. . This stepwise effect can also be achieved by moving the air from one source following the serpentine pattern from right to left in FIG. 4, which essentially represents the countercurrent flow of air to move the tobacco. Thus, the air exiting the particular zone becomes the incoming air for the adjacent zone on the left.

In order to carry out the process of the present invention, it is possible to process both the whole tobacco leaf, bright tobacco, chopped or cut, either expanded or unexpanded, or selected portions of tobacco such as stems or reconstituted tobacco. The process can be applied to any of the above species, including aromatized tobacco. For a particular case of tobacco drying, it has been found that an unexpanded tobacco charge can

-129133 be dried continuously at substantially room temperature in a substantially countercurrently modified spiral dryer with feeder, Frigoscandia, from a moisture content of from about 21 to about 15% in about an hour. In this case, air entered the top of the unit at about 29.5 ° C, with a RH of 58% and exited at 25 ° C and a RH of 68%. Drying was carried out with little or no heat treatment of the tobacco.

Alternatively, the process of the invention may be used to dry tobacco having a temperature significantly higher than room temperature, e.g., tobacco at 93.3 ° C to 121 ° C. When the tobacco is dried at this high temperature, the temperature and relative humidity of the drying air are adjusted to create suitable conditions for carrying out the process of the invention.

Analogously to tobacco humidification, it has been found that drying is best accomplished in a minimum amount of time by adjusting the final air humidity level lower than would be appropriate to prepare the tobacco at the desired final humidity, thereby increasing the air-tobacco humidity gradient and accordingly, the driving force causing drying. However, unlike the humidification process, the air flow can be maintained at a level much lower than that which equilibrates with tobacco of the desired OV content after drying.

Experiment 1

To demonstrate the advantage of the humidification process for dry expanded tobacco in which the water is dosed more slowly than in the spray method in a cylindrical vessel, we placed 20 g of tobacco fill in a sealed desiccator. This sample was impregnated with liquid carbon dioxide and expanded in an expansion tower at 288 ° C. The VOC content of this tobacco fill was 3.4%. It has been calculated that about 1.89 grams of water will be needed to increase the OV content to 11.5%. This amount of water was placed in a small glass container with a rubber stopper with a 3.2 mm inner diameter glass tube passing through the stopper. This vessel was also tightly sealed in a desiccator. After nine days, all water was adsorbed by tobacco. Its subsequent analysis revealed a volatile matter, OV, of about 11.5%. Here we mean tobacco before it has been equilibrated with air at 60% relative humidity and a temperature of 23.9 ° C for 24 to 48 hours. This alignment procedure is generally used as a means to achieve

-139133 of the standard state of the tobacco before measuring the cylinder volume CV and specific volume SV, as well as before the screening tests. After this standard alignment, the tobacco moistened in the desiccator had a cylindrical volume, CV, of about 9.5 cm ³ / g and a specific volume, SV, of about 2.9 cm ³ / g with a volatile matter content, OV of about 11.6% ·. For comparison, if a sample of the same tobacco was placed directly inside the buffer chamber under standard conditions, then the equilibrium volatile content, OV, was 11.3% and the CV and SV were successively 9.4 cm ³ / g and 2.7 cm ³ / respectively. . A third sample of expanded tobacco filling would be moistened in a spray column so that the volatile content was about 11.5%. After equalizing this sample, the CV showed about 8.5 cm ³ / g and an SV of about 1.9 cm ³ / g at an equilibrium OV of about 11.6%.

As can be seen from the TAB data. 1, the tobacco moistened slowly in the desiccator showed a significant improvement in the CV and SV equilibrium values compared to the values for the sample which had been humidified by the spray method. This sample also showed a slight improvement in CV and SV values over the sample that was directly leveled in the buffer chamber.

TAB. 1

Sample as such balanced OV [%] SV [cm ³ / g] OV [%] CV [cm ³ / g] SV [cm ³ / g] Exit sz sz carries 3.4 3.0 11.3 9.4 2.7 Moistened in the cylinder 11.5 1,8 11.6 8.5 1, 9 desiccator 11.5 2.7 11.6 9.5 2.9

A second set of experiments was performed in a buffer chamber for humidifying the tobacco fill. A PGC (Parameter Generation and Control) chamber ⁹ was used for this purpose. This chamber was equipped with a Micro-Pro 2000 microprocessor supplied by Parameter Generation and Control Inc., which allowed a controlled escalation of ¹⁹ conditions inside the chamber.

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Experiment 2

About 1359 g of smoke treated tobacco impregnated with liquid carbon dioxide and expanded under conditions similar to those described in Test No. 1 was placed on a sieve in a layer about 5 cm high. The screen had solid edges and mesh at the bottom and was placed in a buffer chamber. The sample was humidified for one hour in air at a temperature of about 23.9 ° C with an initial relative humidity of about 36%, which was gradually increased to a final relative humidity of about 60%. The downward movement of the air through the tobacco layer had a velocity of about 23 cm / sec. This experiment was repeated at intervals of 3, 6 and 12 hours. The results are presented in TAB. 2 and show that, for periods of up to about 6 hours and under these experimental conditions, it does not affect the wetting rate of CV and SV tobacco. The slower the speed, the higher the CV and SV values were found. In addition, the humidification of the present invention provides CV values of at least about 1 cm ³ / g and SV values of at least 0.2 cm ³ / g higher than those achieved with tobacco moistened in spray cylindrical containers. However, it has been found that the greatest benefit is obtained by escalating in time as short as one hour.

TAB. 2

sample such balanced in the buffer chamber OV [%] SV [cm ³ / g] OV [cm ³ / g] CV [cm ³ / g] exit from the tower 3.1 3.06 11.33 9.71 spray can 11.51 1.61 11.37 8.61 escalation 1 hour 10.83 1.85 11.38 9.72 escalation 3 hours 11.44 1.88 11.36 9.81 escalation 6 hours 11.45 1, 90 11.30 9.88 12 hour escalation 11.41 1.97 11.27 9.89

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Experiment 3

A laboratory study was conducted on the effect of humidification rate and temperature on the CV and SV values of tobacco. Seven sets of experiments were carried out with tobacco impregnated with carbon dioxide and expanded in an expansion tower at 288 ° C. The expanded tobacco was moistened in the following ways:

1) Equalizing at 24 hours in a buffer chamber at 60% RH and 23.8 ° C at an air velocity of tobacco bed of about 12.7 cm / sec;

2) Spraying with water to increase the OV content to about 7.5% and then leveling for 24 hours as in method (1).

3) Spraying with water up to 7.5% OV and then final wetting in a spray barrel;

4) Spraying water at about 7.5% OV and then using a stepwise varying relative humidity from 46 to 60%; and

5) Increasing air humidity from RH 46 to 60%.

Humid air humidification was performed inside a PGC buffer chamber equipped with a microprocessor to control the gradation at selected intervals. The following conditions were selected:

1) Grading times: 30, 60 and 90 minutes;

2) Air temperatures of 23.8 ° C and 35 ° C

3) successive air velocities upward through a layer of tobacco of about 23 cm / sec and downward through a layer of tobacco of 89 cm / sec; and

4) Tobacco layer thickness: 51 mm

Tobacco used in all humidifiers, except that passed through a cylindrical spray can, was removed at the exit of the tower after expansion and sealed in a double plastic bag prior to humidification. Therefore, the tobacco had to be cooled to room temperature from 93 ° C, which is the temperature at the exit of the expansion tower, before being humidified. The tobacco, still in the sealed sack, was sufficiently heated prior to humidified air at 35 ° C to prevent condensation of the water on the tobacco when contacted with humid air. The data for these test sets is shown in the TAB. 3a to 3e.

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TAB. 3a

as it is balanced sample OV [%] SV [cm ³ / g] OV [%] CV [cm ³ / g] X exit from the tower 3.43 3.02 11.31 9.04 S spray only 8.06 2.14 11.68 8, 66 C spray & roller 11.53 1, 81 . 11.59 8.59 F spray & step 90 ¹² min (46 to 60% RH, 23.9 ° C) 11.27 1.87 11.51 9.01 H spray & stepwise 90 min (46 to 60%) RH, 23.9 ° C) 10.96 1.98 11.36 9.48 I sample H held 15 min at 60% RH and 23.9 ° C) 11.54 1.95 11.56 9.40 J spray & stepwise 60 min (46 to 60% RH, 23.9 ° C) 10.37 2.38 11.28 9.58 K sample J held 15 min at 62% RH and 35 ° C) 11.17 2.26 11.22 9.88

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TAB. 3b

as it is balanced sample OV [%] SV [cm ³ / g] OV [%] CV [cm ³ / g] X exit from the tower 3.01 2.58 11.34 9.23 S spray only 7.51 2.13 11.39 8, 87 C spray & roller 11, 86 1.59 11.64 8.07 F spray & stepwise 60 min (46 to 60% RH, 23.9 ° C) 10.55 1.64 11.45 8.86 G sample F held 15 min at 60% RH and 23.9 ° C) 11.56 1.64 11.42 8.61 H spray & step 30 min (46 to 60%) RH, 23.9 ° C) 10.28 1.97 11.27 8.99 I sample H held 15 min at 62% RH and 23.9 ° C) 11.73 1.82 11.25 8, 61

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TAB. 3 c

as it is balanced sample OV [%] SV [cm ³ / g] OV [%] CV [cm ³ / g] X exit from the tower 1.81 2.78 11.37 9.23 B in steps of 60 min (46 to 60% RH, Deň: 32 ° C 10.91 1.86 11.47 8.86 C in steps of 60 min (46 to 60% RH, 23.9 ° C 10.53 2.02 11.28 9.20 D stepwise 90 min (46 to 60% RH, Deň: 32 ° C 10.84 1.99 11.45 8.90 E just spray 5.39 2.37 11.25 8.71 F spray & directly placed for 30 min at 60% RH, 35 ° C 10.80 1.81 11.27 8.39 G spray & stepwise 60 min (46 to 60% RH, 35 ° C) 10.66 1.85 11.23 8.65 H spray & stepwise 90 min (46 to 60% RH, 35 ° C) 10.76 1.82 11.24 8.62 I spray & staged 60 min (46 to 60% RH, 23.9 ° C) 10.65 1.90 11.23 8.75 J spray & stepwise 90 min (46 to 60% RH, 23.9 ° C) 10.57 1.87 11.38 8.74 K spray & directly inserted for 30 min to 60% RH, 23.9 ’C 10.73 1.87 11.22 8.64 L spray & roller 10.98 1.60 11.39 8.28

-199133

TAB. 3d

as it is balanced sample ov ST OV CV [%] [cm ³ / g] [%] [cm ³ / g] TI exit from the tower 2.83 3.01 11.92 9.46 T2 loaded directly for 30 min, to RH 60% at 23.9 ° C 11.24 2.27 11.77 9.08 T3 stepwise 90 min, 30 to 60% RH, 23.9 ° C 11.08 2.24 11.83 9.29 T4 stepwise 90 min, 30 to 60% RH, 23.9 ° C 9.77 2.24 11.85 9.43 SI just spray 4.78 2.82 11.66 8.98 S2 spray & directly for 30 min to 60% RH, 23.9 ° C 11.10 2.19 11.64 8.89 S3 spray & stepwise 90 min 46-60% RH, 23.9 ° C 10.54 2.25 11.27 9.05 S4 spray & stepwise 60 min 46-60% RH, 23.9 ° C 10.56 2.22 11.73 9.03 S5 spray & incrementally 30 min 46-60% RH, 23.9 ° C 9.74 2.29 11.67 9.19 C spray & roller 10.48 1.95 11.81 8.80

-209133

TAB. 3e

conditions of escalation as it is balanced start OV I%] speed air [cm / sec] time (mini Temperature I ° c 1 RH range > £ About - SV Icm ³ / g] OV [%] CV cm ´ / g | SPRAY INTO THE TOWER -9.2 0.79 1 1,86 5,05 OUTPUT FROM THE TOWER 3.94 2.82 11.72 9.49 OUTPUT 1. SPRAYING STAGES 5.64 2.72 11.82 9.48 EXIT FROM CYLINDER CONTAINER 10.36 2.04 11.66 9.28 AND 3.9 119 60 23.9 30-58 6.67 2.39 11.65 9.76 (B) 5.6 89 60 23.9 30-58 8.44 2.45 11.82 9.91 C 3.9 97 60 23.9 45-58 7.83 2.25 11.65 9.57 D 5.6 97 60 23.9 45-58 8.44 2.39 11.79 9.66 E 3.9 97 60 23.9 47-62 11.10 2.33 11.74 10,02 F 5.6 89 60 23.9 47-62 10.10 2.41 11.59 10,08 G 3.9 91 60 23.9 30-62 8.13 2.20 11.89 9.63 H 5.6 89 60 23.9 30-62 9.41 2.41 11.79 10.11 AND 3.9 102 60 23.9 47-62 10.21 2.15 11.76 8.98 J 3.9 91 60 23.9 47-64 10.18 2.13 11.94 9.03 TO 3.9 91 60 23.9 35-64 9.07 2.23 11.90 9.51 L 3.9 91 60 32.2 35-60 8.65 2.17 12.09 8.59 M 3.9 91 60 32,3 » 45-60 10.11 2.39 11.92 10,02 N 5.6 91 60 32.2 45-60 10,08 2.39 11.93 10,02 0 3.9 122 60 32.2 47-64 10.88 2.31 11.96 9.51 P 3.9 122 60 32.2 47-64 11.30 2.33 11.95 9,30

The data presented in TABs 3a to 3e show a gain in CV values ranging from 0.5 to about 1 cm ³ / g and a gain in SV values from about 0.3 to about 0.4 cm ³ / g, which may be achieved by a stepwise change in the RH of air in the humidification of cold tobacco, i.e. tobacco at a temperature of from 23.9 ° C to about 35 ° C, as compared to spraying in a cylindrical vessel used in the humidification of hot tobacco leaving the expansion tower. The volatile matter content, OV achieved by using a stepwise humidification directly at the tower outlet, proved to be more advantageous than an initial tobacco spraying of increasing the OV value to about 7%, followed by a stepwise humidification. There was no significant difference in SV and CV values for step-humidified tobacco using humid air with an initial RH around

5 / .; .--., ......,. ... "._............................................ ..........................

-21- 9133% compared to tobacco humidified in a stepwise manner with an initial RH of about 30%, or tobacco humidified in either 60 or 90 minutes. It has also been observed that the tobacco can be wetted either by moving the air downward at speeds from about 89 to about 119 cm / s or upwards at speeds up to about 23 cm / s without observing significant differences in SV and CV values. Additionally, it was observed that the stepwise humidification yielded equivalent or better CV and SV values than tobacco after expansion in an expansion chamber humidified by direct exposure to 60% RH at 23.9 ° C in the buffer chamber. Finally, it was found that water spraying leading to an increase in OV of about 7.5% and subsequent staged humidification provided better CV and SV values than spraying followed by final wetting in the spray cylinder.

Experiment 4

Attempts have been made to determine the effect of air flow and its velocity on the abduction, channeling, and compaction of tobacco. These tests were performed using two PGC buffer chambers. In both chambers, the actual air flow was approximately 14.16 m ³ per minute. The air flowed through a layer of tobacco upwardly in one chamber and downwardly in the other chamber. Tobacco samples in a 51 mm deep layer were placed inside the 124 x 145 mm open mesh sieves with the sulfur at the bottom and the solid edges 102 mm high. These screens were located inside the buffer chambers. The air was forced to flow through the samples by covering the unoccupied floor area with cardboard and sealing all gaps with tape. The air velocity was varied by varying the number of sample screens that were loaded into the chamber. Tobacco for these experiments would be impregnated with carbon dioxide and expanded at about 288 ° C. The tobacco was moistened in the first stage by spraying with water to about 8% OV immediately after expansion. The conditions inside the test chamber were controlled at 23.9 ° C and 60% RH. Both the blade anemometer (Airflow Instrumentation, Model LCA 6000, Frederick, Maryland) and the hot wire anemometer ¹³ (Alnor Instrument Company, Skokie, Illinois, Thermometer Model 8525) were used to measure air velocities. These instruments were positioned to measure upstream immediately above, and downstream below the sample layer.

-229133 cm / s was observable and followed by significant

Upon moving the air, a slight lifting of the tobacco was observed immediately after switching on the average flow rate, even at speeds as low as 13.2 cm / s. Then small air ducts formed and the tobacco settled. As a result of these channels we have found that the flow rate is very inhomogeneous from 11.2 cm / s to 22.86 cm / s for an average flow rate of about 13.2 cm / s. As the average air flow rate increased, the channeling became more pronounced and, at flow rates above 22.9, the kidnapping and blowing of the tobacco channeling became significant.

With downward air movement, some layer compaction was observed and a corresponding decrease in air velocity through the layer was observed at all speeds studied. This is shown in TAB. 4. At an initial velocity of about 97.5 cm / s, the tobacco layer was compacted by 28% and as a result the air velocity of the layer was reduced to about 72 cm / s. At an initial velocity of about 72 cm / sec or less, the compaction of the layer was about half that at 97.5 cm / sec and the air flow through the tobacco was much less reduced.

TAB 4.

INFLUENCE OF LAYER COMPACTITY ON LAYER AIR FLOW Initial air velocity [cm / s] layer depth [mm] beginning end change [%] beginning end change [%] 97.5 71.6 27 Mar: 51 39.1 28 81.8 73.2 11 51 41.9 18 71.6 67.6 6 51 43.2 15 Dec 52.8 49.8 6 51 45.7 10 21.8 20.8 5 51 48.3 5

On the basis of these experiments, it has been determined that expanded tobacco can be preferably wetted by the step method under the following conditions:

(a) Time: from about 60 to 90 minutes;

(b) RH: from an initial RH of about 30 to 45% to a final RH of about 60 to 64%;

(c) Temperature: from about 23.9 to 35 ° C;

(d) Airflow: upward speed to 22.9 or downward to about 112.7 cm / sec.

-239133

Pokus č.5

Approximately 65.25 kg per hour of a mixture of smoke and burley ¹⁴ impregnated with carbon dioxide according to the procedure described in co-pending and co-pending application Cho et al., SN 07 / 717,067, and expanded as described above of the examples, passed through a cooling conveyor to reduce the temperature from about 93.3 to about 29.4 ° C prior to introduction into the Frigoscandia Model GCP 42 spiral unit. Tobacco passes through the spiral unit from bottom to top. Air flows from above to the bottom, essentially creating a countercurrent flow of tobacco and air. This arrangement provides a stepwise moistening of the tobacco as a result of the continuous dehydration of the tobacco air. Tobacco enters the process with about 3% and comes out with 11% OV. The CV value of the leveled feed material was about 10.53, while the CV value of the leveled wetted material was 10.46 cm ³ / g, indicating no significant loss of tobacco filler performance in the humidification process, in other words, no statistically significant variance analysis was found. loss of filling capacity. In addition, the sieve test did not show a measurable decrease in tobacco particle size due to the humidification process.

Pokus č.6

Numerous experiments have been carried out with tobacco expanded at different tower temperatures in which the tobacco has been humidified in the process of the invention. In each experiment, about 68 kg / h of tobacco relative to the moistened tobacco mass was moistened in the modified Frigoscandia spiral unit described in Experiment 5. The temperature of the air entering the humidifier was set to about 29.4 ° C and the relative humidity to about 62%. The air exiting the humidifier unit typically had a temperature of about 32.2 to 35 ° C and a relative humidity of about 40 to 45%. As shown in TAB. 5, the tobacco moistened according to the present invention showed no decrease in filling capacity.

-249133

TAB. 5

balanced The type of tobacco Experiment no. Tower temperature [° C] OV input 1% l OV exit I% 1 CV input [om '/ gl OV entrance! % l CV exit [crrP / gl OV output [% l Bright FO 205C 287.8 2.70 11.16 9.93 11.87 9.40 12.00 FO 205A 321 2,1 1 11.58 10.41 11.57 10.83 11.56 FO 205B 329 1.87 9.99 11.30 1 1,30 10.90 11.50 Bright FO 206A 304 2.47 11.09 10.00 12.34 10.20 11.74 FO 217 321 2.59 10.86 10.49 11.79 10.51 11.63 Burley FO 206B 248 3.11 10.75 12.39 10.91 12.31 10.52 FO 206C 271 2.95 10.22 12.08 10.85 12.41 10.40 FO 214 271 3.00 10.4 11.3 10.4 11.2 10.4

smoke-treated tobacco light tobacco from Kentucky

Experiment No. 7

About 90.6 kg of smoke treated tobacco per hour with OV about

21.6% were fed to the modified Frigoscandia unit described in Experiment 5 operating as an oven. The tobacco flow on the spiral conveyor of the drying unit was oriented from bottom to top. Air flowed from the top to the bottom of the unit, creating essentially countercurrent flow of tobacco relative to the air. The tobacco was successfully dried to about 12.2% OV in a residence time of about 60 minutes using air having an inlet temperature of about 35 ° C and a RH of about 35%. The air leaving the drying unit was about 28.3 ° C and had a humidity of 62% RH. The tobacco entering and leaving the unit was cold to the touch with an estimated temperature of about 23.8 ° C, indicating that no heat treatment of the tobacco took place. There was no change in the CV value of the balanced tobacco due to drying. This particular drying experiment was designed to minimize heat treatment. Similar drying results can be obtained using higher temperatures in controlled heat treatment.

Although the invention has been specifically described in connection with the preferred embodiments, it is to be understood that various changes in the process and details may be made without departing from the spirit and scope of the patent.

Claims (34)

PATENT CLAIMS A process for increasing the humidity of an organic material having the following steps: (a) contacting the organic material with an air stream of relative humidity near the equilibrium conditions of the organic material, and (b) increasing the relative humidity of the air stream in contact with the organic material to increase the content. humidity of the organic material in such a way that the relative humidity of the air stream in contact with the organic material is maintained near the equilibrium conditions of the organic material until the desired humidity of the organic material is reached. 2. The process of claim 1, wherein the CV of the aligned organic material after step (b) is not significantly less than the equalized CV of the organic material before step (a). 3. Procedure for increasing the humidity of organic material, which consists of the steps of: (a) forming an organic material layer by depositing it on a conveyor, (b) contacting the organic material with an air stream flowing substantially countercurrent to the organic material, and (c) realizing conditions in which a portion of the air stream moisture content passes into the organic material that the relative humidity of the air stream in contact with the organic material is maintained near the equilibrium conditions of the organic material, causing a gradual dehydration of the air stream, and the organic material is gradually hydrated with substantially countercurrent airflow relative to the organic material flow until the desired moisture content of the organic material. -269133 4. Method claimed in claim 13 ^15, characterized in, that the value of the sample equilibrated CV of the organic material after step (c) is not significantly less than the equilibrated CV of the organic material prior to step (b). 5. A process according to any one of Claims 1 to 4 wherein the temperature of the organic material is below 38 [deg.] C. before contact with the air stream. 6. The process of any one of claims 1 to 5, wherein before the step of bringing the organic material into contact with the air stream, the initial moisture content of the material is in the range of 1.5-13%. 7. The process of claim 6 wherein prior to the step of bringing the organic material into contact with the air stream, the initial moisture content of the material is in the range of 1.5 to 6%. 8. The process of claim 3 wherein the desired moisture content of the organic material after step (c) is in the range of about 11 to about 13%. 9. The process of any one of the preceding claims, wherein the air stream coming into contact with the organic material has a relative humidity of about 30 to 64% and a temperature of about 21 to 49 ° C. 10. A process according to any preceding claim, wherein the temperature of the air stream is selected to provide the desired thermal treatment to the organic material, wherein the relative humidity of the air stream is selected to humidify. 11. A process according to any one of the preceding claims, wherein the material to be processed is tobacco. -279133 12. The process of any one of the preceding claims, wherein the treated material is expanded tobacco. 13. The process of claim 11 wherein the tobacco is selected from the group consisting of expanded and unexpanded tobacco, whole leaf tobacco, cut or chopped tobacco, stems, recombined tobacco, and any combination thereof. 14. A process for reducing the moisture of an organic material comprising the steps of: (a) contacting the organic material with an air stream ¹⁰ having a relative humidity close to or below the equilibrium conditions of the organic material, and (b) reducing the relative humidity of the air in contact with the organic material while reducing the moisture content of the organic material in such a way the relative humidity of the air stream in contact with the organic material is maintained near or below the equilibrium conditions of the organic material until the desired humidity of the organic material is reached. 15. The process of claim 14, wherein the CV value of the balanced organic material after step (b) is not significantly lower than the CV value of the balanced organic material before step (a). 16. A process for reducing the moisture content of an organic material comprising the steps of: (a) forming an organic material layer by depositing it on a conveyor, (b) contacting the organic material with an air stream flowing substantially upstream of the organic material layer, and (c) realizing conditions where part of the moisture content of the air stream becomes organic -289133 material in such a way that the relative humidity of the air stream in contact with the organic material is maintained near the equilibrium conditions of the organic material, causing a gradual hydration of the air stream and the organic material gradually dehydrated with substantially countercurrent airflow relative to the organic material flow up to when the desired moisture content of the organic material is achieved. 17. The method of claim 16, wherein the CV value of the aligned organic material sample after step (c) is not significantly less than the equalized CV value of the organic material prior to step (b). 18. The process of any one of items 14 to 17, further comprising the step of heating the organic material from about 38 ° C to about 121 ° C prior to step (a). 19. The process of any one of claims 14 to 18, wherein the temperature of the organic material is below 121 [deg.] C. prior to the contact with the air stream. 20. The process of claim 19 wherein the temperature of the organic material is below 38 [deg.] C. prior to the contact with the air stream. 21. The process of claims 14 to 20 wherein the organic material has a moisture content of from about 11 to 40% prior to the step of contacting the air stream. 22. The process of Claims 14 to 20 wherein the air stream has a relative humidity of from about 20 to about 60% and a temperature of from about 21 ° C to about 49 ° C prior to the step of contacting the organic material. 23. The method of any one of claims 14 to 22, wherein the temperature of the air stream is -299133 selected to provide the necessary heat treatment. 24. The process of any one of claims 14 to 22, wherein the temperature of the air stream is selected so as not to cause substantially any heat treatment. 25. Method according to any of points 14 to 24 on č u j and- c i s e t i m that temperature air flow is in range from about 24 to 121 ° C. 26. Method according to any of points 14 to 25 on č u j i - wherein the organic material is tobacco. 27. The method of claim 26, wherein the tobacco is cut tobacco. 28. The method of claim 26, wherein said tobacco is selected from the group consisting of expanded or unexpanded tobacco, solid tobacco, cut or chopped tobacco, stems, recombined tobacco, and any combination thereof. 29. The process of any preceding claim, wherein the step of contacting the organic material with the air stream is carried out in a continuous manner using a spiral conveyor wherein the air stream flows in a substantially countercurrent flow direction of the organic material. 30. The process of any preceding claim, wherein the step of contacting the organic material with the air stream is carried out in a continuous manner using a linear conveyor. 31. The method of claim 30, wherein the linear conveyor is designed to form a plurality of multiple zones of increasing humidity. -309133 32. The process of any one of the preceding claims, wherein the step of contacting the organic material with the air stream is conducted such that the air stream has a velocity of from about 0.23 m / s to about 1.22 m / s. 33. The process of any preceding claim, wherein the step of contacting the organic material with the air stream is carried out such that the air stream is directed either downward or upward and passes through the organic material. 34. The process of any one of items 1 to 10 and 15 to 25, wherein the organic material is a hygroscopic organic material. 35. The method of claim 29, wherein the hygroscopic organic material is selected from the group consisting of fruits, vegetables, cereals, coffee, pharmaceuticals, tea, and any combination thereof. 36. The method of claim 29, wherein the spiral conveyor comprises a reservoir having a plurality of trays, and the air substantially flows through the reservoir sequentially through the individual trays.