LV11096B - Process for adjusting the moisture content of organic materials - Google Patents
Process for adjusting the moisture content of organic materials Download PDFInfo
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- LV11096B LV11096B LVP-93-1174A LV931174A LV11096B LV 11096 B LV11096 B LV 11096B LV 931174 A LV931174 A LV 931174A LV 11096 B LV11096 B LV 11096B
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- A—HUMAN NECESSITIES
- A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
- A24B—MANUFACTURE OR PREPARATION OF TOBACCO FOR SMOKING OR CHEWING; TOBACCO; SNUFF
- A24B3/00—Preparing tobacco in the factory
- A24B3/04—Humidifying or drying tobacco bunches or cut tobacco
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- A—HUMAN NECESSITIES
- A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
- A24B—MANUFACTURE OR PREPARATION OF TOBACCO FOR SMOKING OR CHEWING; TOBACCO; SNUFF
- A24B3/00—Preparing tobacco in the factory
- A24B3/12—Steaming, curing, or flavouring tobacco
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- Manufacture Of Tobacco Products (AREA)
- Drying Of Solid Materials (AREA)
- Treatment Of Sludge (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Processing Of Solid Wastes (AREA)
- Tea And Coffee (AREA)
- Polysaccharides And Polysaccharide Derivatives (AREA)
- Storage Of Fruits Or Vegetables (AREA)
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- Macromolecular Compounds Obtained By Forming Nitrogen-Containing Linkages In General (AREA)
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- Chemical Or Physical Treatment Of Fibers (AREA)
- Artificial Filaments (AREA)
- Control And Other Processes For Unpacking Of Materials (AREA)
- Investigating Or Analyzing Materials By The Use Of Fluid Adsorption Or Reactions (AREA)
- Solid-Sorbent Or Filter-Aiding Compositions (AREA)
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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
LV 11096
PROCESS FOR ADJUSTING THE MOISTURE CONTENT OF ORGANIC MATERIALS
This invention relates to processes for reordering, i.e., increasing the moisture content, and drying tobacco or other hygroscopic organic materiāls, such as pharmaceutical and agricultural products, including but not limited to fruits, vegetables, cereals, coffee, and tea. More particularly, this invention relates to the use of controlled humidity air to moisten or drv these materiāls.
The art has long recognized the desirabilitv of controlling the moisture content of various organic materiāls, including tobacco. For example, the moisture content of tobacco that has been processed into a useful product has been altered numerous times. Each processing step, e.g., stem removal, cutting, blending components, adding flavors, expansion and fabricating into cigarettes, requires certain optimum moisture Ievels, vhich must be controlled carefully, to ensure top quality tobacco and other hygroscopic organic material products. Moreover, the manner in which the moisture content of the tobacco ls altered can have a lasting effect on the physical, Chemical and subjective characteristics of the final product. Accordingly, the methods used for bringing about 2 changes in the moisture content of tobacco or other organic materiāls are important.
Reordering of expanded tobacco is a particularly demanding process. Typically, tobacco 5 obtained from the expansion process will have a moisture content below 6%, and often less than 3%. At such low moisture contents the tobacco is verv susceptible to breakage. Additionally, the expanded tobacco structure is subject to collapse upon 10 reordering, i.e., a full or partial return of the tobacco to its unexpanded state. This collapse results in a loss of filling power, thus decreasing the benefit derived from the expansion process.
Various means for reordering expanded tobacco 15 have been used. The most common method is to subject the tobacco to a water spray, typically while tumbling the tobacco in a rotāting cylinder. Another method is to use saturated steam as the reordering medium. Yet another method is to blow high humidity air through a 20 moving bed of tobacco on a conveyor, as shown in U.S. Patent No. 4,178,946.
None of the above methods has been found to be completely satisfactory for use on expanded tobacco. Tumbling tobacco in a spray cylinder results in 25 breakage of the fragile expanded tobacco. Direct contact with iiouid vater tends to cause collapse of the expanded tobacco structure. Steam reordering also results in expanded tobacco structure collapse. While this may be partially attributed to the high 30 temperatures in a steam environment, exposing expanded tobacco to any gaseous environment in which vater condensation occurs, such as a steam or highly humidified air environment, results in collapse.
One method, which has been emploved to avoid 35 these difficulties, is to place dry, expanded tobacco LV 11096 in a chamber containing air at a desired humidity Ievel and allow the tobacco to equllibrate in the chamber over a period of from 24 hours to 48 hours. Air velocity through the chamber is ķept very low, 5 typically not more than about 25 feet per minūte. This procedure results in little or no collapse of the expanded tobacco structure. However, the long times required, 24 hours to 48 hours, have limited its application to laboratory purposes. 10 Attempts have been made to reduce the residence time required of such equilibration processes by increasing air velocity. Such approaches have been unsuccessful due to an inability to duplicate the maintenance of filling power observed in slow 15 laboratory equilibration, the size of conveyors required to carry the tobacco in order to accomnodate the long residence times required, the nonuniformity of the moisture content of the tobacco product exiting such conveyors, and the incidence of fires in such 20 units as described in U.S. Patent No. 4,202,357.
The use of drying as a means for controlling moisture content during the processing of tobacco is of equal importance as that of reordering. When tobacco is dried, both physical and Chemical changes can occur 25 that affect the phvsical and subjective qualitv of the product. Therefore, the method of drying tobacco is exceedingly important.
There are tvo types of drying eguipment generally used by the tobacco industry: rotary driers 30 and belt or apron driers. Pneumatic-type driers are also used occasionally. The particular dryer used is chosen for the drying operation required. Belt or apron driers, for example, are normally used for strip tobacco, vhereas rotary driers are used for cut 4 tobacco. Both rotary and belt driers are used for drying stems.
In a belt dryer, tobacco is spread on a perforated belt and air is directed either upward or 5 dovnvard through the belt and tobacco bed. Nonuniform drying of the tobacco often occurs due to channels being blovm in the bed allowing the drying air to locally bypass the tobacco.
Most rotary driers used in the tobacco 10 industry are lined with steam coils and may function as either indirect or direct heat driers depending on vhether the heat is applied outside or inside the drier Shell containing the tobacco. Moreover, they may be operated either co-currently where the tobacco and air 15 flow in the same direction or countercurrently where the tobacco and air flow in opposite directions.
Rotary drying must be controlled carefully to avoid overdrying, vhich causes both Chemical changes and unnecessary breakage by the rotary motion. In 20 addition, if drying occurs too quickly, an impervious layer may be formed on the outer surface of the tobacco making it difficult for moisture on the inside of the tobacco to diffuse to the surface. The formation of such a layer slows the drying rāte and results in 25 nonuniformity in drying.
Use of a rotary or belt drier to drv tobacco can result in a thermal treatment that may result in Chemical and physical changes to the tobacco. while not always undesirable, these changes are driven bv the 30 objective of removing water from the tobacco. In typical tobacco applications, the need to drv the tobacco in a limited amount of time dictates a thermal treatment result from the drying step, preventing optimization of thermal treatment apart from the 35 process constraints imposed by drying. - 5 - LV 11096
The present invention is defined by the independent claims, to which reference should be made.
Embodiments of the invention have the advantage that tobacco or other suitable hygroscopic and agricultural products, including but not limited to fruits, vegetables, cereals, coffee and tea may be recordered or dried with little or no breakage, even of fragile tobacco exiting the expansion process. It further has the advantage of reordering expanded tobacco with little or no loss of expanded tobacco structure and enables drying of tobacco or other suitable hygroscopic organic material at approximately atmospheric pressure, for example, without the use of vacuum and at a selected temperature wherein the thermal treatment imparted can be controlled during the process to an extent unattainable in conventional tobacco drying processes.
In a preferred process embodying the invention, changes in the moisture content of tobacco or other suitable organic materiāls are affected by contacting the tobacco with air which has 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 of the air is continuously increased or decreased, as appropriate, during processing to maintain a controlled differential between the relative humidity of the air and the equilibrium relative humidity of the organic material with which it is in contact. Careful, continuous control of relative humidity allows control of the rāte of moisture mass transfer between the organic material and its environment so that structural changes to the tobacco are minimized. Utilization of relative humidity as the primary driving force for moisture mass transfer allows independent control of thermal treatment. This process can be carried out in 6 either a batch or continuous fashion. Furthermore, the process can be carried out without the use of rotating cylinders and the consequent breakage that occurs with their use.
Examples of processes embodying the invention and of preferred embodiments thereof will now be described with reference to the accompanying drawings, in which:
Figurē 1 is a plot of air relative humidity (RH) percent versus tobacco moisture content or OV;
Figurē 2 is a schematic diagram of a laboratory apparatus for reordering hygroscopic organic material according to this invention by ramping air RH over time;
Figurē 3 is a cut-away view of an exemplary apparatus for carrying out this invention on a continuous basis;
Figurē 3a is a cross-sectional view of a portion of the spiral conveyor stack shown in Figurē 3, which shows the path of the air flow relative to the path of the hygroscopic organic material;
Figurē 4 is a schematic diagram of an alternate apparatus suitable for carrying out this ivnention on a continuous basis;
Figurē 5 is a bl-ock diagram illustrating the application of the present invention to a reordering process; and
Figurē 6 represents a typical RH profilē of the air adjacent to the tobacco over time, obtained during reordering in the apparatus of Figurē 3 .
The present invention relates to processes for adjusting the moisture content of tobacco or other suitable hygroscopic organic material, such as pharmaceutical and agricultural products, including but not limited to fruits, vegetables, cereals, coffee, and LV 11096 - 6 A - tea while minimizing breakage, changes to the physical structure, or thermally driven changes to the Chemical composition of the tobacco to be treated. More particularly, the present invention relates to the use of controlled humidity air for the purpose of either reordering or drying tobacco or other suitable hygroscopic organic material. The moisture content of tobacco or other1suitable hygroscopic organic material is either increased or decreased by gradually and continuously increasing or decreasing, as appropriate, the relative humidity of the air contacting the tobaccor or other suitable hygroscopic organic material. In this manner moisture transfer is controlled, allowing other process variables such as temperature, air velocity, and air pressure to be optimized separately.
Two commonly used methods for characterizing the physical structure of tobacco are cylinder volume. 7 (CV) and specific volume (SV). These measurements are particularly valuable in assessing the benefits of this process in reordering tobacco.
Cylinder Volume (CV)
Tobacco filler weighing 20 grams, if unexpanded, or 10 grams, if expanded, is placed in a 6-cm diameter Densimeter cylinder, Modei No. DD-60, designed by the Heinr. Borgvaldt Company, Heinr. Borgvaldt GmbH, Schnackenburgallee No. 15, Pos-fack 54 07 02, 2000 Hamburg 54 West Germany. A 2-kg piston, 5.6 cm in diameter, is placed on the tobacco in the cylinder for 30 seconds. The resulting volume of the compressed tobacco is read and divided by the tobacco sample veight to yield the cvlinder volume as cc/grara. The tēst determinēs the apparent volume of a given weight of tobacco filler. The resulting volume of filler is reported as cylinder volume. This tēst is carried out at Standard environmental conditions of 75°F and 60% RH; conventionally, unless otherwise stated, the sample is preconditioned in this environment for 24-48 hours. 'Specific Volume (SV)
The term "specific volume" is a unit for measuring the volume occupied by solid objects, e.g., tobacco, using Archimedes1 principle of fluid displacement. The specific volume of an object is determined by taking the inverse of its true density. Specific volume is expressed in "cc/grams". Both mercury porosity and helium pycnometry are suitable methods for making these measurements, and the results have been found to correlate well. When helium pycnometry is used, a veighed sample of tobacco, either "as is", dried at 100°C for 3 hours, or eguilibrated, - 8 - LV 11096 is placed in a celi in a Quantachrome Penta-Pycnometer Modei 2042-1 (manufactured by Quantachrome Corporation, 5 Aerial Way, Syosset, New York). The celi is then purged and pressured vith helium. The volume of helium 5 displaced by the tobacco is compared with volurae of helium required to fill an empty sample celi. The tobacco volume is deterrained based on the fundamental principles of the ideal gas law. As used throughout this application, unless stated to the contrary, 10 specific volume was determined using the same tobacco sample used to determine OV, i.e., tobacco dried after exposure for 3 hours in a circulating air oven controlled at 100°C.
As used herein, moisture content may be 15 considered equivalent to oven-volatiles content (OV) since not more than about 0.9% of tobacco veight is volatiles other than water. Oven-volatiles determination is a simple measurement of tobacco veight loss after exposure for 3 hours in a circulacing air 20 oven controlled at 100°C. The veight loss as percentage of initial veight is oven-volatiles content. "Sieve tēst" refers to a method of measuring the shred-length distribution of a sample of cut filler. This tēst is frequently used as an indicator 25 of degradation of shred length during processing.
Tobacco filler veighing 150 ± 20 grams, if unexpanded, or 100 ± 10 grams, if expanded, is placed in a shaker apparatus. The shaker apparatus utilizēs a series of 12-inch diameter, round screen trays (manufaccured by 30 W.s. Tyler, Inc., a subsidiary of Combustion
Engineering Inc. Screening Division, Mentor, Ohio 44060) that meet ASTM (American Society of Testing Materials) standards. Normai screen sizes for sieve trays are 6 mesh, 12 mesh, 20 mesh, and 35 mesh. The 35 apparatus has a shaking distance (stroke) of about 9 1-1/2 inches, and a shaking speed of 350 ± 5 rpm. The shaker agitates the tobacco for a period. of 5 minūtes in order to separate the sample into different particle size ranges. Each of the particle size ranges is weighed, thus yielding a particle size distribution of the sample.
Laboratory experiraents have shown that attempts to reorder tobacco rapidlv by exposing the tobacco to high humidity air results in CV losses. It has also been shown that CV losses occur when either condensation or overwetting occur within a bed of expanded tobacco. Condensation occurs when humid air contacts tobacco which is at a temperature below the dew point of the humid air. Overwetting can occur when moisture variations are created within a tobacco bed due to non-uniform exposure to humid air. Therefore, a successful humid-air reordering system must operate at a relatively slow rāte with good control of the air relative humidity, air temperature, air flow and pressure through the bed of tobacco. This is best accomplished by gradually increasing the moisture content of the humid air passing through the tobacco in such a manner that the tobacco is exposed to a stream of air which is nearly at equilibrium with the tobacco.
Referring to FIG. 1, line ABC is an isotherm for 750F for a typical expanded bright tobacco. This isotherm relates the tobacco1s OV to the RH of the air surrounding it at eouilibrium for a given temperature. Thus point B indicates that at 75°F and 60% RH, this sample of expanded tobacco will have an OV of about 11.7% upon equilibration. Line DEF of FIG. 1 represents a typical RH profilē for tobacco which is reordered, according to this invention. Line GEF of FIG. 1 represents an alternative RH profilē which also has been found satisfactory. Line HF of FIG. 1 LV 11096 - ίο - represents a path typical o£ the prior art such as laboratory reordering in an equilibrium chamber at verv low air velocities. Line IJ of FIG. 1 represents the application of this invention to the drying of the tobacco. FIG. 1 shows that reordering tobacco frora an OV of about 6.5%, where it would be in equilibrium with air having about 30% RH, to an OV of about 11.7%, where it would be in equilibrium with air having about 60% RH, could be accomplished by exposing it to air which is increased in moisture from about 40% RH in small increments over a period of time until it reaches about 60% RH', rather than being exposed to 60% RH air directly. When carried out under these slovlv changing conditions, mass transfer between the air stream and the tobacco is relatively slow because the driving force is small, and the expanded tobacco structure is maintained. Reordering of expanded tobacco with no loss in CV may also be achieved by exposing the tobacco to air v/hich is increased in moisture content from about 40% RH in small increments over a period of time of about 40 to about 60 minūtes until it reaches an RH of about 62%. This reduces the overall time required to complete the reordering process without significantly changing the expanded tobacco structure. Thus, lines DEF and GEF of FIG. 1 each represent effective embodiments of the present invention when reordering'tobacco.
Referring to FIG. l, near-equilibrium conditions betveen the air stream and the tobacco are illustrated by line segment EF and line ABC. It will be appreciated that at tobacco OV's below about 7% the difference between the relative humidity of the air in equilibrium with the tobacco and the relative humidity of the huraid-air stream used for reordering can be 11 quite large without adversely affecting the filling power of the tobacco. It will also be appreciated that at tobacco OV's from about 7.5% to about 11.5% the relative humidity of the humid air stream used for reordering can be from about 2% to about 8% above the relative humidity of the air in equilibrium with the tobacco, with the greater deviation from eguilibrium corresponding to the lower tobacco OV, vithout adversely affecting the filling power of the tobacco.
When the present invention was used to dry tobacco, no measured loss in tobacco CV was observed. This was found to be the case even when the relative humidity of the drying air stream was significantly below the relative humidity of the air in eguilibrium vith the tobacco, i.e., the relative humidity of the drying air stream was below the eguilibrium conditions of the tobacco. Therefore, it will be appreciated that line IJ of FIG. 1 illustrates only one of manv possible paths which may be used when drying tobacco according to the present invention.
The present invention may be carried out as either a batch or a continuous process. When carried out as a batch reordering process, the relative humidity of the air stream contacting the tobacco is increased over time to provide a continuous increase in moisture content of the tobacco. This may be accomplished in an environmental chamber such as the one illustrated in FIG. 2. The tobacco to be reordered is placed at a bed depth of about 2 inches, in trays having screen mesh bottoms, inside an environmental chamber so that a stream of controlled humidity air mav pass through the tobacco in a downward direction. Chambers ranging in size from about 20 cubic feet to about 80 cubic feet (manufactured by Parameter Generation and Control, Inc. , 1104 Old US 70, West, - 12 - LV 11096
Black Mountain, N.C. 28711) were used in a nuraber of studies. The environmental chambers were equipped with microprocessors which permitted controlled ramping of humid-air conditions vithin the chamber. Tests were conducted in which dry, expanded tobacco was reordered frora initial OV Ievels of about 2% to final OV Ievels of about 11.5% by incrementally ramping the RH from initial Ievels as low as about 30% RH and as high as about 52% RH over periods ranging from about 30 minūtes to about 90 minūtes to final RH Ievels between about 59% and about 65%. Air velocities in the range of about 50 feet/minute to about 200 feet/minute were used. RH and temperature measurements were monitored vith a Thunder modei 4A-1 instrument (manufactured by Thunder Scientific Corp., 623 Wyoming, S.E.,
Albuquerque, New Mexico 87123). Air velocities were measured with an Alnor Thermo Anemometer modei 8525 (manufactured by Alnor Instrument Co., 7555 N. Linder Ave, Skokie, Illinois 60066) . Tests in which relative humidities were ramped from starting values as high as about 52% to final RH values as high as about 62% in time as short as about 40 minūtes, resulted in a reordered tobacco with full CV retention when compared to similar tobacco reordered in an environmentally controlled room with air maintained at 60% RH and 75°F passing through the tobacco at low velocity for 24 hours to 48 hours. Ramping in this manner was successful with humid-air velocities as high as about 200 feet/minute and temperatures from about 75°F to about 90°F. Expanded tobacco reordered in this manner shoved minimal, if any, loss of CV compared to expanded tobacco reordered in an environmentally controlled room.
The present invention may be carried out as a continuous process most effectively in a Frigoscandia 13 self-stacking spiral conveying machine, such as the one shown in FIG. 3. This apparatus is a specially modified Modei GCP 42 spiral freezer supplied by Frigoscandia Food Process Systems A8 of Helsingborg, Sweden. Dry tobacco to be reordered enters the unit 10 on a conveyor 13, is conveyed through the unit 10 in a spiral georaetry from the bottom to the top of the spiral stack 14 as shown, and exits at the tobacco exit 11 after reordering. Humidified air is blown down through the tobacco from the humid air inlet 15 to the bottom of the spiral stack 14 where it exits through the humid air exit 16, essentially flowing countercurrent to the direction of tobacco flow, i.e., the majority of the humid-air flow is from the top of the stack downward through the tiers of the tobacco bed, while the tobacco moves upv/ard following the spiral path of the conveyor. A small portion of the humid air follows the spiral path of the convevor stack from top to bottom in a true countercurrent path.
These types of air flov/s are shown in FIG. 3a. This arrangement has been found to effectively duplicate the ramping of RH obtained in the apparatus of FIG. 2.
Referring to FIG. 3a, which is a cross-sectional view of a portion of the spiral conveyor stack 14 shown in FIG. 3, the path of the air flow 20 and 22 relative to the path of the tobacco bed 21 is illustrated. As shown in FIG. 3a, the air flow 20 and 22 is from the top of the stack downward. The tobacco flow is from the bottom to the top of the unit and is illustrated as moving from the right to the left-hand side of FIG. 3a as it progresses up the spiral conveyor stack 14. The major portion of the air flow 20, wnich is essentially countercurrent to the path of the tobacco, is directed through the tier of the tobacco bed 21 and contacts the tobacco bed on the Ievel - 14 - LV 11096 immediately below, while a sraall portion of the air flow 2 2 passes ove'r the tobacco bed 21 in a direction countercurrent to the path of the tobacco bed 21. This portion of the air flow 22 may later pass through the tobacco bed 21.
Key to the successful implementation of this invention, in the case of reordering, is providing a means of steadily increasing the relative humidity of the air in contact with the tobacco as the tobacco OV increases. The Frigoscandia self-stacking spiral conveyor, by virtue of its self-stacking design, channels the majority of air flow downward through the multiple tiers of conveyor (the conveyor stack), which are carrying tobacco. 8y feeding tobacco into the bottom of the conveyor stack and humidified air into the top of the stack, the overall flow of air and tobacco is essentiallv countercurrent. This essentially countercurrent flow provides a natūrai continuous RH gradient in the air contacting the tobacco because the air is progressivelv dehydrated as it moves downward through the tiers of tobacco undergoing the reordering process. By judicious selection of conveyor belt speed, air and tobacco flow rātes, and control of entering air temperature and RH, conditions like those used in batch laboratorv ramped reordering experiments can be approximated on a continuous basis. For reordering approximately 150 Ib/hr of 3% OV expanded tobacco, belt speeds which provide from about 40 minūtes to about 80 minūtes residence time and air conditions of from about 75°F to about 950F with entrance relative humidities of from about 61% to about 64% at air flov/s of from about 1000 cubic feet per minūte (CFM) to about 2500 CFM have been found to provide full reordering vithout significant CV 15 loss or measurable breakage of the tobacco using the modified Frigoscandia GCP 42 spiral unit.
Devices for recording relative huraidity over time such as Modei 29-03 RH/Temperature recorder (manufactured by Rustrak Instruments Co. of E. Greenwich, RI) , have been run through the Frigoscandia unit while reordering tobacco. These devices have shown a steady increase in air relative humidity as the device is conveyed up the spiral stack, with initial RH recordings of from about 3 5% to about 45% at the bottom of the stack, where tobacco is driest, to about 62% at the top of the stack, where the tobacco is most fully reordered. FIG. 6 is a typical curve of RH versus time obtained with the Rustrak unit. The percent RH of the air adjacent to the tobacco bed versus time is shown in FIG. 6. Tobacco with an initial OV of about 3% entered the spiral reordering unit and was contacted with air having an RH of about 43% (Point A of FIG. 6) . FIG. 6 shovs that as the tobacco progressed through the spiral reordering unit, the RH of the air adjacent to the tobacco increased from about 43% to about 62% at the exit of the unit (Point B of FIG. 6) . The tobacco had i an OV of about 11% upon exiting the spiral reordering unit. The RH of the air entering the spiral reordering unit was controlled to yield reordered tobacco with no significant loss of CV.
Other means of providing ramped RH air, such as the unit shown in FIG. 4, may also be used to carry out this invention on a continuous basis. Referring to FIG. 4, tobacco enters the unit at the tobacco inlet 40 on conveyor 43, and exits at the tobacco exit 41. Air with steadily increasing relative humidity is blovn, either up flow or down flow, through the tobacco bed 42 in a multiplicity of zones 44 to reproducē the effect - 16 - LV 11096 of ramping in the apparatus of FIG. 2. This ramping effect could be accomplished by moving air from a single source in a serpentine fashion from the right to left in FIG. 4, providing essentially countercurrent air flow to the direction of tobacco movement. Thus, air exiting a given zone would become the inlet air to the adjacent one on its left.
To carry out the process of the present invention, one may treat whole cured tobacco leaf, tobacco in cut or chopped form, either expanded or non-expanded tobacco or selected parts of tobacco such as stems or reconstituted tobacco. The process may be applied to any or ali of the above with or vithout flavorings added. For the specific case of drying tobacco, it has been found that non-expanded cut filler can be dried continuously, at essentially ambient temperature, by essentiallv countercurrent flow through the modified Frigoscandia self-stacking spiral convevor from a tobacco moisture content of about 21% OV to about 15% OV in about one hour. In this case, air entered the top of the unit at about 85°F and about 58% RH and exited at about 77°F and about 68% RH. Drying was accomplished with little or no thermal treatment of the tobacco.
Alternatively, the process of the present invention may be used to dry tobacco having a temperature significantly above ambient temperature, e.g., tobacco at about 200°F to about 250°F. When tobacco in this temperature range is dried, the RH and temperature of the drying air is adjusted to provide appropriate conditions for carrying out the process of the present invention.
Analogous to reordering tobacco, it was found that drying was best accomplished in a minimum amount of time by setting the final air moisture content lower 17 than that which would be required to bring the tobacco to its desired.final air moisture Ievel, thereby increasing the air-tobacco moisture gradient, and accordingly, the driving force to bring about the drying. Unlike the reordering process, the final moisture content of the air stream can be maintained at a Ievel much less than that: which v/ould be in eguilibrium with the tobacco at the desired OV Ievel after drying.
Ex~periment No. 1
To demonstrate the advantage of reordering dry, expanded tobacco by metering water to .it slowly as compared to spray cvlinder reordering, a 20-gram sample of tobacco filler was placed in a sealed desiccator. This sample had been impregnated with liquid carbon dioxide and expanded in an expansion tower at 550°F.
The OV of this expanded tobacco filler was 3.4%. It was calculated that approximately 1.89 grams of water would be required to increase this sample's OV content to 11.5%. This amount of water was put into a small glass bottle with a rubber stopper having a l/8-inch inside diameter glass tube extending through it. The bottle was also sealed in the desiccator. After nine days, ali of the water had been adsorbed by the tobacco. The tobacco was then analyzed and found to have an as-is OV of about 11.5%. As used herein, asis refers to tobacco prior to being equilibrated in an environmental chamber with air maintained at 60% RH and 75°F passing through it at a low velocity for a period of from 24 hours to 48 hours. This process of equilibration is generally used as a means for bringing tobacco to a Standard condition prior to CV, SV and sieve measurements being made. After this Standard eguilibration, the desiccator-reordered tobacco had a - 13 - LV 11096 CV of about 9.5 cc/grara and an SV of about 2.9 cc/gram at an OV of about 11.6%. By comparison, when a second sample of the same tobacco was placed directly inside the equilibration chamber and reordered bv equilibration under Standard conditions, the eguilibrated OV was about 11.3% and the CV and SV values vere about 9.4 cc/gram and about 2.7 cc/gram, respectively. A third sample of the expanded tobacco filler was reordered in a spray cylinder to an as-is OV of about 11.5%. After equilibration, this sample had a CV of about 8.5 cc/gram and an SV of about 1.9 cc/gram at an eguilibrium OV of about 11.6%.
As seen from the data in TABLE 1, the tobacco sample that was reordered in the desiccator by a slow raetering of water showed a significant improvement in equilibrium CV and SV compared to the sample that had been spray reordered. This sample also showed a slight improvement in CV and SV when compared with the sample eguilibrated directly in the ecuilibration chamber TABLE l Samole As _Ls Eouilibraced OV(%) S V(cc/gm) OV(%) CV(cc/gm) SV(cc/gm) Tavver Eac 3.4 3.0 113 9.4 2.7 Cylioder Reordered 11-3 1.8 11.6 8.5 1.9 Desiccacor 11.5 2.7 11.6 9.5 2.9 A second sec of experiments was carried out using an environraental chamber to reorder expanded tobacco filler. For this purpose, a Parameter Generation and Control (PGC) chamber was used. This chamber was equipped with a Micro-Pro 2000 microprocessor supplied by Parameter Generation and Control Inc., which permitted controlled ramping of the conditions inside the chamber. 19
Exoeriment No. 2
Approximately 3 pounds of bright tobacco impregnated with liguid carbon dioxide and expanded under conditions similar to those described in Experiraent No. 1, vas placed at a bed depth of about 2-inches inside a tray. The tray, vhich had solid sides and a screen mesh bottom, vas placed inside an environmental chamber. The sample was then reordered over a 1-hour period using air at about 75°F with an initial RH of about 36% ramped to a final RH of about 60%. Air movement vas in a downward direction through the tobacco bed at a velocity of about 45 ft/min. This experiment was then repeated over time intervāls of 3 hours, 6 hours, and 12 hours. The results, presented in TABLE 2, indicate that for ramping periods up to about 6 hours the rāte of reordering does affect tobacco CV and SV, at these experimental conditions.
The slover the rāte of reordering, the higher the CV and SV observed. Moreover, reordering according to the present invention results in CVs at least about 1 cc/gram greater, and SVs at least about 0.2 cc/gram greater than those observed for tobacco reordered in a spray cylinder. Hovever, it has been found that most of this benefit is achieved by ramping in as little as one hour. LV 11096 - 20 -TABLE 2
Equilibraced Ια An
As fs EnvironmentaI Chamber OV(%) SV(cc/gm) ov(%) CV(cc/gm) Tower Exic 3.10 3.06 1153 9.71 Spray Cylinder 1151 1.61 11.37 8.61 Ramped 1 hr. 10.83 1.85 1158 9.72 Ramped 3 hr. 11.44 l.SS 1156 9.81 Ramped 6 hr. 11.45 1.90 11.30 9.83 Ramped 12 hr. 11.41 Γ.97 11.27 9.S9
Exoeriment No. 3 A laboratory studv was conducted on the affect of both reordering rāte and temperature on tobacco CV and SV. Seven sets of runs were carried out using tobacco impregnated with carbon dioxide and expanded in an expansion tower at about 550eF. The expanded tobacco was reordered by the following methods: (1) By equilibrating for 24 hours in an environmental chamber at 60% RH and 75°F with air movement through the tobacco at a rāte of about 25 ft/min; (2) By spraying with water to increase the OV to about 7.5%, then equilibrating at 60% RH and 75°F for 24 hours as in (1); (3) By spraying with water to increase the OV to about 7.5%, then final reordering in a spray cylinder; (4) By spraying with water to about 7.5% OV, then using humid-air ramped from an initial RH of about 46% to a final RH of about 60%; and - 21 - (5) By ramping with humid air from about 46% RH to about 60% RH.
Reordering with humid air was carried out inside a PGC environmental chamber equipped with a microprocessor to control ramping over selected time intervāls. The follov/ing conditions were selected: (1) Ramping times: 30, 60, and 90 minūtes; (2) Air temperatures: 75°F and 95eF; (3) Air Velocities: upward through the tobacco bed at about 45 ft/min, and downward through the tobacco bed at about 175 ft/min; and (4) Tobacco bed thickness: 2 inches.
The tobacco used for ali reordering except through the spray cylinder, was collected at the tower exit after expansion and sealed in double plastic bags prior to reordering. As a result, the tobacco cooled from about 200eF, the temperature of the tobacco at the expansion tower exit, to ambient temperature before reordering. When reordering by ramping at about 95°F, the tobacco, while stili in the sealed bags, was pre-warmed sufficiently to avoid condensation upon contact with the humid air before being exposed to the ramped conditions. Data for these runs is presented in TABLES 3a through 3e. LV 11096 - 22 -TABLE 3a
As 1s Eoui' iibrated SamDle OV(%) SV(cc/gm) O < 0 < n n 1 X Exic Tower 3.43 3.02 1131 9.04 s Through Spraycrs Only 8.06 2.14 11.63 8.66 c Through Sprayers & Cylinder 11-53 LSI 11.59 859 F Through Sprayers & Rampcd 90 min (46% RH to 60% RH, 75° F) 11.27 1.87 1151 9.01 H Through Sprayers &. Rampcd 90 min (46% RH to 60% RH. 75° F) 10.96 1.98 1156 9.48 I Sample H Hcld 15 min at 60% RH, 75° F 11.54 1.95 1156 9.40 J Through Sprayers & Ramoed 60 min (46% RH to 62% RH, 95° F) 10.37 2.38 11.28 9.85 K Sample J Held 15 min at 62% RH, 95° F 11.17 2.26 11.22 9.88 TABLE 3b As !s Eoui iibrated Samole OV(%) sv( cc/gm) OV(%) CV(cc/gm) X Exu Tower 3.01 2-58 1134 9.23 s Through Sprayers Only 7.51 2.13 1139 8.87 c Through Spraycrs &. Cylinder 11.S6 1.59 11.64 8.07 F Through Spravcrs &. Rampcd 60 min (46% RH to 60% RH, 75° F) 10.55 1.64 11.45 8.86 G Sample F Held 15 min at 60% RH, 75° F 11.56 1.64 11.42 8.61 H Through Sprayers & Ramoed 30 Min (46% RH to 60% RH, 75° F) 10.23 1.97 11.27 8.99 I Sample H Held 15 min at 60% RH, 75° F 11.73 1.82 11.25 8.61 23 TABLE 3c
As f$ Eauilibraterl SamDle 0V(%) SV(cc/gm) 0V(%) CV(cc/gm) A Exit Tower 1.81 2.78 1137 9.23 5 B Ramped 60 min (46% RH to 60% RH, 95° F) 10.91 1.36 11.47 8.86 C Ramped 60 min (46% RH (o 60% RH, 75° F) 10.53 2.02 11.28 9.20 10 D Ramped 90 min (46% RH to 60% RH, 95° F) 10.84 1.99 11.45 8.90 E Through Sprayers 5.39 2.37 11.25 8.71 F Through Sprayers &. Put Directly at 60% RH, 95° F for 30 min 10.80 1.81 11.27 839 15 G Through Sprayers & Ramped 60 min (46% RH to 60% RH, 95° F) 10.66 1.85 11.23 8.65 H Through Sprayers & Ramped 90 min (46% RH to 60% RH, 95° F) 10.76 1.S2 11.24 8.62 I Through Sorayers & Ramped 60 min (46% RH to 60% RH, 75° F) 10.65 1.90 11.23 8.75 20 J Through Sprayers & Ramped 90 min (46% RH to 60% RH, 75° F) 10.57 1.87 1138 8.74 K Through Sprayers &. Put Directly at 60% RH, 75° F for 30 min 10.73 1.87 11.22 8.64 L Through Sprayers and Cylinder 10.98 1.60 1139 8.28 - 24 - LV 11096 TABLE 3d
As Is Eauilibrated Samoie OV(%) Sv(cc/gm) OV(%) CV(cc/gm) T1 Exic Towcr 2.S3 3.01 11.92 9.46 5 T2 Put Directly at 60% RH, 75° F, 30 min 11.24 2.27 11.77 9.08 T3 Ramped 90 mia (46% RH to 60% RH, 75° F) 11.03 2.24 11.83 9.29 10 T4 Ramped 90 min (30% RH to 60% RH, 75° F) 9.77 2.39 11.85 9.43 S1 Through Sprayers 4.78 2.32 11.66 8.98 S2 Through Spraycrs & Put Dircctlv at 60% RH, 75° F for 30 min 11.10 2.19 11.64 8.89 15 S3 Through Sprayers & Rampcd 90 min (46% RH to 60% RH, 75° F) 10.54 2.25 11.27 9.05 S4 Through Sprayers &. Ramped 60 min (46% RH to 60% RH, 75° F) 10.56 2.22 11.73 9.03 S5 Through Spraycrs & Ramped 30 min (46% RH to 60% RH, 75° F) 9.74 2.29 11.67 9.19 20 C Through Sprayers and Cylinder 10.48 1.95 11.81 8.80 ε
C£J CN 04 oo _ oo OO O — o> O o O ON U ΤΓ Ol o- CN O\ Ό o O p o CN > CN Cn o Cn CN CN CN oo -O CJ ā oli e? cni 04 o no 04 Ol On ΤΓ CN ON CN Ό > r- OO p p OO p Γ-* r-* no OO O* O» o — —v s CO wo 04 04 ΤΓ CN Όι O| O ro o __ υ p oo Γ- O r-i ΤΓ 04 m ro ΤΓ 04 ΤΓ vn o 1-0 04 04 Ol Ol Ol 04 04 04 04 04 04 04 > <$| < co o £ OO NT — Ό r- ro tt O O ΓΟ cļ > _ CN Ό ON Ό CO ΤΓ — —- — 5* 04 < o rS WN o Ό od O»’ od — o OO CN O r—1 oo oo oo oo 04 04 04 04 04 — C ^ CN no n*N no CO| Ό Ό Ό Ό Ό tη —* « .p OS 0£ r- O O CO o ON no nO ΤΓ r~- ΤΓ O- O ON o ON o rr CM crH α C 1 o ε u. f- L· o; Ό» Όι no CO ιΛ nO no CO CO «/“i r- {— o- o* P- O- r- O» o» c c CJ Ε I H 3 o o O o o O o O O CC o o <5 •o Ό vO o Ό Ό c , >»^ ε ·- ~ <= < ^ '5 WO nO O o O nO o ηΛ O sa o = >· on r- C\ CN CN r- oo O* O > u — < 04 04 Cž. < > ^3 C. “ es oc ΛΧ 2 > <3 U1 UJ CN Ό CN o CN O CN cO CN (λ ot > o 1- e: LU > UJ O <; G 2 _1 oN no rn nO ON nO ro n<N ON o δ > H H CJ Q f- t— J- UJ — u X X X u. UJ UJ UJ < α o Q U1 U. o — — IT) O in ·—c rH LV 11096
Start AvgAir Time Temp RH 0V(%) SV(cc/gm) 0V(%) CV(cc/gm) m O cn
τ CN
νΛ ON
Ov od O <Z>
<*nj O O
Ov' Ο m Ο Ο Ο ΟΝ ο r\j Ον m Ό ΝΟ Ον Ον Ον m m r- Ον ΟΝ _ rn — OJ — m m m m ΓΝ OJ ΓΝ OJ rvi r^i r^i oo r- wn — oo oo o — o NO — O CO r*r O ON od O O o z o CO rr rr o o O ΤΓ c ^ O t o 1 vO NO NO nO NO ¢3 ^ r-* VTN r- r-· "5Γ c-v m rr *7 ΤΓ "T lu vn O O O O o o r-* r- Ov ON ON Ov ON Ο Ό Ο Ο Ο Ο ο νΟ ο ο Ο Ό
Ο ΟΟ > ο ιη Ο Ό Ο οο Ο οο Ο οο Ο οο Ο Ο -3· Ό* rvi γν ON ON Ov Ov O Ov ON m m m m vn m Σ Ζ Ο e- 27
The data presented in TABLES 3a through 3e show that gains of from about 0.5 cc/grara to about 1 cc/gram in CV and from about 0.3 cc/gram to about 0.4 cc/gram in SV may be achieved by raroped reordering of cooled tobacco, i.e., tobacco at about 75°F up to about 95°F, as compared to cylinder spray reordering of hot tobacco exiting the expansion tower. Ramped reordering directly from the tower exit OV was found to be preferable to first spraying the tobacco to increase its OV content to about 7% folloved by ramped reordering. No significant difference was seen in the CV or SV of tobacco reordered by ramping using humid air with an initial RH of about 46% as compared to tobacco reordered by ramping from an initial RH of about 30%, or in tobacco reordered by ramping over a period of either about 60 minūtes or about 90 minūtes. It was also observed that tobacco could be reordered either with the air movement directed downward through the tobacco bed at velocities of from about 175 ft/min to about 235 ft/min or with the air directed upward through the tobacco bed at up to about 45 ft/min with no significant differences in CV or SV. Additionally, it was observed that ramped reordering yielded equivalent or better CVs and SVs as compared to tobacco reordered by placing it directly in an environmental chamber at 60% RH and 75°F after exiting the expansion tower. Finally, it was observed that spraying with vater to increase the OV to about 7.5% folloved by ramping with humid air resulted in better CVs and SVs as compared to spraying folloved by final reordering in a spray cylinder.
Exoeriment No. 4
Tests were conducted to determine the effect of air flow and air velocity on entrainment, - 28 - LV 11096 channeling, and compaction of the tobacco. These tests were carried out using two PGC environmental chambers. In both chambers, actual air movement was approximately 500 CFM. Air movement was in an upward direction 5 through the tobacco bed in one PGC chamber, and in a downward direction through the tobacco bed in the other. Tobacco samples, 2-inches in depth, were placed inside open-top trays 5" X 5 3/4" with screen mesh bottoms and with 4-inch high solid sides. These trays 10 were placed on shelves inside the environmental chambers. Air was forced through the samples by covering the non-occupied shelf area with cardboard and sealing any cracks with tape. Air velocity was varied by changing the number of sample containers through 15 which the air passed. Tobacco used for these tests was impregnated with carbon dioxide and expanded at about 550°F. The tobacco had been reordered through a first stage by spraying with water to about 8% OV immediatelv after expansion. Conditions inside the chambers during 20 the tests were controlled at about 75°F and about 60% RH. Both a vane anemometer (Airflow Instrumentation, Modei LCA 6000, Frederick, Maryland) and a hot-wire anemometer (Alnor Instrument Company, Skokie, Illinois, Thermometer Modei 8525) were used to measure air 25 velocities. These instruments were placed directly above or below the samples for air movement in the upvard and downward directions, respectively.
With air movement in an upvard direction, some slight lifting of the tobacco was observed 3 0 inuaediately when the air was turned on at average velocities as low about 26 ft/min. Small air channels then formed, and the tobacco would settle. As a result of these channels, air flow was found to be very non-uniform across the tobacco bed (about 22 ft/min to 35 about 45 ft/min for an average flow of about 29 26 ft/min). With increasing average air flows, more channeling was apparent, and at above 45 ft/min considerable entrainraent and "blov up" of tobacco vas observed, folloved by significant channeling of the 5 bed.
With air movement in a downward direction some compaction and corresponding reduction in air velocity through the beds vas observed at ali velocities studiea. This is shovn in TABLE 4. At an 10 initial velocity of about 192 ft/min, tobacco bed depth compacted about 28%, and, as a result, the air velocity through the bed vas reduced to about 141 ft/min. At initial air velocities of about 141 ft/min or less, tobacco bed compaction vas about half that observed at 15 about 192 ft/min, and air flov through the tobacco bed vas reduced much less. 20 25 TABLE 4 Effccc of Bed Comnaction on Air Velocitv Through Bed Air Ve!ocicy (ft/min) Bed Dcpih (in) Start End % Chamte Start End % Chamze 192 141 27 2 1.45 28 161 144 11 2 1.65 1S 141 133 6 2 1.70 15 104 98 6 2 1.80 10 43 41 5 2 1.90 5
Based on the above experiments it vas determined that expanded tobacco can be reordered preferably by ramping at the folloving conditions: 30 (a) Time: from about 60 minūtes to about 90 minūtes; (b) RH: from an initial RH of from about 30% to about 45% to a final RH of from about 60% to about 64%; (c) Temperature: from about 75 °F to about 9 5 ° F ; 35 - 30 - LV 11096 (d) Air flow: upward at velocities up to about 45 ft/min or downward at velocities up to about 235 ft/min.
Exūeriment No. 5
Approximately 150 lb/hr of a mixture of bright and burley tobacco, which had been impregnated with carbon dioxide according to the process described in co-pending and commonly assigned application Cho et al., S.N. 07/717,067, and expanded as described in the above examples, was passed through a cooling conveyor to reduce its temperature from abouu 200°F to about 85°F prior to being fed to a modifiea Frigoscandia Modei GCP 42 self-stacking spiral unit. Tobacco flow through the spiral unit was from the bottom to the top. Air flow vas from the top to the bottom of the unit, providing an essenciallv countercurrent flow of tobacco to air. This arrangement provided ramped reordering of the tobacco as a result of the continuous dehydration of the air bv the tobacco. Tobacco entered the process at about 3% OV and exited at about 11% OV. Equilibrated CV of the feed material was about 10.53 cc/gm, while the eguilibrated CV of the reordered material vas about 10.46 cc/gm, indicating no significant loss of filling pover of the tobacco across the reordering process, i.e., no statistically significant loss of filing power as determined by Standard analysis of variance procedure. Additionally, there vas no measurabie reduction in tobacco particle size, as determined by the sieve tēst, during the reordering process.
Experiment No. 6 A series of experiments was carried out using various types of tobacco expanded at different tower temperatures in vhich the tobacco was reordered 5 according to the process of the present invention. In each run, approximately 150 lb/hr of tobacco, based on reordered tobacco mass, was reordered in the modified Frigoscandia self-stacking spiral unit described in Experiment No. 5. The inlet air to the reordering unit 10 was set at about 85°F with a relative humiditv of about 62%. The air exiting the reordering unit was typically about 900F to about 95°F with a relative humidity of about 40% to about 45%. As shown in TABLE 5, tobacco reordered according to the process of the present 15 invention shoved no significant loss of filling pover. LV 11096 Τ3 Φ Ρ ια u Ρ ο ιΟ σ U r-* ο ιη ιη 3 « , • > 0 '—* 04 rH f—4 ο rH rH rH Η V tn Ο r“) Ο 3 GO σ\ > Ο Ο . . υ 0 <3\ Ο ο '—' |Ή 1—4
-<τ η 04 Ο θ' ιο ιη ΗΓ rH rH ο Ο Ο rH γΗ rH rH ι—4 Ο rH rH ι—4 04 ιη Π Τ oj Ο ο (Ν (Ν ι-Η r—1 γΗ rH rH rH wl *—·» C ον® ο* ο CC η η Ο . . . ι—4 rH (—4 ι—4 γ—4 rH £ σ' η rH Ο C —>, σ\ η > ·-* 0 • . ο υ σι ο rH γΗ «—4
•c* rH in η o* σι co T OJ rH o o o rH rH rH rH rH ΙΟ W5 < ε-
«5 CC σ\ m σ\ 4J r—« > 3 ον° ι—4 rH σι Ο 0 w •—4 rH
o cn o> co o m O n o O 04 OJ rH rH rH rH r—4 <—4 cn lO in OJ o CO θ' OJ *3* rH o o O O rH rH rH rH rH
CM η I
> c θ\° . 70 . 11 . 87 Ο -Η OJ 04 rH θ' <Tl rH n O n rH σι o OJ OJ n OJ co U . <U α 3 ε U* Ο ο ιη 0 α» 0 ιη rH OJ ε* "— m 10 νο O o O O o CO rH co OJ OJ n iO τ in in Ο < 00 ιη ιη ιη ο σ ο (Ν CM 04 C • 3 0 Ο Ο Ο IX 2 ΰ~ι &Η < CO cj VO Ό vO o rH O O rH OJ 04 OJ CM 04 O o o O O £u uu Cžm X Ct·
0 u 4-1 P u J3 Oi <0 0) cn σ> rH xi α •*H •rH U O >1 i-l 3 ε» £-< en 03 00 in O 33
Exoeriment No. 7
Approximately 200 lb/hr. of bright tobacco with an OV of about 21.6% was fed to the modified Frigoscandia self-stacking unit described in Experiment 5 No. 5 operating as a drying unit. Tobacco flow through the spiral drying unit was from the bottora to the top. Air flow was from the top to the bottom of the unit, providing an essentially councercurrent flow of tobacco to air. The tobacco was successfullv dried to about 10 12.2% OV in about 60 minūtes residence time using air with an inlet temperature of about 95°F and an inlet RH of about 35%. Air exiting the drying unit was at about 83°F and about 62% RH. The tobacco entering and exiting the drying unit was cool to the touch, with an 15 estimated temperature of about 75°F, indicating that substantially no thermal treatment of the tobacco had taken place. No change in the equilibrated tobacco CV occurred as a result of the drying process. This particular drying experiment was designed to minimizē 20 thermal treatment. Similar drying results could be achieved using higher temperatures to provide a controlled degree' of thermal treatment.
While the invention has been particularly shown and described with reference to preferred 25 embodiments, it will be understood by those skilled in the art that various changes in form and details may be made vithout departing from the spirit and scope of the invention. LV 11096
- 34 -CLAIMS 1. A process for increasing the moisture content of organic material which comprises the steps of: (a) contacting organic material with an air stream having a relative humidity near the equilibrium conditions of the organic material, and (b) increasing the relative humidity of the‘ air stream contacting the organic material to increase the moisture content of the organic material in such a manner that the relative humidity of the air stream contacting the organic material is maintained near the equilibrium conditions of the organic material until the desired moisture content of the organic material is achieved. 2. A process according to claim 1, whereby the equilibrated CV of the organic material after step (b) is not significantly less than the equilibrated CV of the organic material prior to step (a). 3. A process for increasing the moisture content of organic material which comprises the steps of: (a) forming an organic material bed by depositing organic material on a conveyor, (b) contacting the organic material with an air stream flowing in a path essentially countercurrent to the path of the organic material bed, and (c) causing a portion of the moisture content of the air stream to be transferred to the organic material m such a manner that the relative humidity of the air stream contacting the organic material is maintained near the equilibrium conditions of the organic material, whereby the air stream is progressively dehydrated and the organic material is progressively hydrated as the air 35 stream flows essentially countercurrent to the path of the organic material bed until the desired moisture content of the organic material is achieved. 4. The process of claim 13, wherein the 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 of claims l to 4, wherein the organic material temperature is below about 38°C (100°F) prior to contacting it with the air stream. 6. A process according to any of claims 1 to 5 , wherein prior to the step of contacting organic material with an air stream the organic material has an initial moisture content of from about 1.5% to about 13%. 7. A process according to claim 6, wherein prior to the step of contacting organic material with an air stream the organic material has an initial moisture content of from about 1.5% to about 6%. 8. A process according to claim 3, wherein the desired moisture content of the organic material after step (c) is from about 11% to about 13%.
9. A process according to any preceding claim, wherein the air stream contacting the organic material has a relative humidity of from about 30% to about 64% at a temperature of from about 21°C (70°F) to about 49°C (120°F) . - 36 - LV 11096 10. A process according to any preceding claim, wherein the temperature of the air stream is selected to provide a desired thermal treatment to the organic material, while the relative humidity of the air stream is selected to provide reordering. 11. A process according to any preceding claim, wherein the organic material is tobacco. 12. A process according to claim 11, wherein the tobacco is expanded tobacco. 13. A process according to claim 11, wherein tobacco is selected from the group comprised of expanded or non-expanded tobacco, whole leaf tobacco, cut or chopped tobacco, stems, reconstituted tobacco or any combination of these. 14. A process for decreasing the moisture content of organic material which comprises the steps of: (a) contacting organic material stream having a relative humidity near or below the equilibrium conditions of the organic material, and (b) decreasing the relative humidity of the air stream contacting the organic material as the moisture content of the organic material decreases in such a manner that the relative humidity of the air stream contacting the organic material is maintained near or below the equilibrium conditions of the organic material until the desired moisture content of the organic material is achieved. 37 15. The process of claim 14, wherein the equilibrated CV of the organic material after step (b) is not significantly lower than the equilibrated CV of the organic material prior to step (a). 16. A process for decreasing the moisture content of organic material which comprises the steps of: (a) forming an organic material bed by depositing organic material on a conveyor, (b) contacting the organic material with an air stream flowing in a path essentially countercurrent to the path of the organic material bed, and (c) causing a portion of the moisture content of the organic material to be transferred to the air stream in such a manner that the relative humidity of the air stream contacting the organic material is maintained near or below the equilibrium conditions of the organic material, whereby the organic material is progressively dehydrated and the air stream is progressively hydrated as the air stream travels in a path essentially countercurrent to the path of the organic material bed until the desired moisture content of the organic material is achieved. 17. The process of claim 16, wherein the equilibrated CV of the organic material after step (c) is not significantly lower than the equilibrated CV of the organic material prior to step (b). 18. A process according to any of claims 14 to 17, further comprising the step of preheating the organic material temperature of from about 38°C (100°F) to about 1210C (2500F) prior to step (a) . - 38 - LV 11096 19. A process according to any of claims 14 to 18, wherein the organic material temperature is below about 121°C (250°F) prior to the step of contacting.it with the air stream. 20. A process according to claim 19, wherein the organic material temperature is below about 38°C (100°F) prior to the step of contacting it with the air stream. 21. A process according to any of claims 14 to 20, wherein prior to the step of contacting the organic material with an air stream the organic material has a moisture content of from about 11% to about 40%.
22. The process according to any of claims 14 to 21, wherein the air stream which contacts the organic material has a relative humidity of from about 20% to about 60% at a temperature of from about 21°C (70°F) to about 49°C (12 0 0 F) . 23. A process according to any of claims 14 to 22, wherein the temperature of the air stream is selected to provide a desired thermal treatment. 24. A process according to any of claims 14 to 22, wherein the temperature of the air stream is selected to provide substantially no thermal treatment. 25. A process according to any of claims 14 to 24, wherein the temperature of the air stream is from about 24 0C (750F) to about 121°C (250°F) . 26. A process according to any of claims 14 to 25, wherein the organic material is tobacco. 39 27. A process according to any of claim 26, vvherein the tobacco is cut tobacco. 28. A process according to claim 26, vvherein tobacco is selected from the group comprised of expanded or non-expanded tobacco, vvhole leaf tobacco, cut or chopped tobacco, stems, reconstituted tobacco or any combination of these. 29. A process according to any preceding claim, vvherein the step of contacting organic material with an air stream is carried out in a continuous manner using a spiral conveyor in vvhich the air stream flovvs in a path essentially counter current to the direction of flow of organic material. 30. A process according to any preceding claim, vvherein the step of contacting organic material with an air stream is carried out in a continuous manner using a linear conveyor. 31. A process according to claim 30, vvherein the linear conveyor is configured to provide a multiplicity of zones of increasing relative humidity. 32. A process according to any preceding claim, vvherein the step of contacting the organic material with an air stream is carried out using an air stream having a velocity of from about 0.23 m/s (45 feet/minute) to about 1.22 m/s (240 feet/minute). 33. A process according to any preceding claim, vvherein the step of contacting the organic material with an air stream is carried out by directing the air stream either dovvnvvard or upvvard through the organic material bed, or by directing the air stream both dovvnvvard and upvvard through the organic material bed. 34 A process according to any of claims 1 to 10 or 14 to 25, vvherein the organic material is a hygroscopic organic material. LV 11096 - 40 - 35. A process according to claim 29, vvherein the hygroscopic organic material is selected from the group comprised of truits, vegetables, cereals, coffee, pharmaceuticals, tea, and any combination of these. 36. A process according to claim 29, vvherein the spiral conveyor comprises a stack having a plurality of tiers and the air stream essentially flovvs through the stack sequentially through successive tiers. - 43 - LV 11096
ABSTRACT
PROCESS FOR ADJUSTING THE MOISTURE CONTENT OF ORGĀNIC MATERIALS A process for reordering tobacco, which results in no significanc decrease in ecuilibrium tobacco CV or significant tobacco degradation, is provided. Tobacco to be reordered is contacted vith an air stream having a relative humidity near the eguilibrium conditions of the tobacco. As the ov content of the tobacco increases, the relative humidit'/ 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 vith an air stream having a relative humiditv near or belov the equilibrium conditions of the tobacco. As the OV content of the tobacco decreases, the relative humiditv of the air stream contacting the tobacco is decreased to affect drving of the tobacco.
It, has been found that tobacco can be reordered or dried successfully in a continuous raanner using a self-stacking spiral conveyor.
Claims (35)
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US07/969,035 US5383479A (en) | 1992-10-30 | 1992-10-30 | Process for adjusting the moisture content of tobacco |
| US07/969,109 US5526581A (en) | 1992-10-30 | 1992-10-30 | Process for adjusting the moisture content of organic materials |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| LV11096A LV11096A (en) | 1996-04-20 |
| LV11096B true LV11096B (en) | 1996-06-20 |
Family
ID=27130521
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| LVP-93-1174A LV11096B (en) | 1992-10-30 | 1993-10-29 | Process for adjusting the moisture content of organic materials |
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| JP (1) | JP3696260B2 (en) |
| KR (1) | KR100281931B1 (en) |
| CN (1) | CN1043183C (en) |
| AT (1) | ATE188846T1 (en) |
| AU (1) | AU679003B2 (en) |
| BG (1) | BG62028B1 (en) |
| BR (1) | BR9304433A (en) |
| CA (1) | CA2109153C (en) |
| CO (1) | CO4230157A1 (en) |
| CZ (1) | CZ294159B6 (en) |
| DE (1) | DE69327631T2 (en) |
| DK (1) | DK0595616T3 (en) |
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| EG (1) | EG20133A (en) |
| ES (1) | ES2144002T3 (en) |
| FI (1) | FI103373B1 (en) |
| GR (1) | GR3033102T3 (en) |
| HK (1) | HK1013785A1 (en) |
| HU (1) | HU219164B (en) |
| LV (1) | LV11096B (en) |
| MX (1) | MX9306795A (en) |
| MY (1) | MY109619A (en) |
| NO (1) | NO304095B1 (en) |
| PL (1) | PL172905B1 (en) |
| PT (1) | PT595616E (en) |
| RO (1) | RO111821B1 (en) |
| RU (1) | RU2120217C1 (en) |
| SK (1) | SK281909B6 (en) |
| TR (1) | TR27107A (en) |
| TW (1) | TW296974B (en) |
| UA (1) | UA29384C2 (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2283604C2 (en) | 2002-03-14 | 2006-09-20 | Джапан Тобакко Инк. | Method for regulating of material moisture content and apparatus for performing the same |
| TW201233345A (en) * | 2010-12-23 | 2012-08-16 | Philip Morris Prod | Method of treating burley tobacco stems |
| CN103284294B (en) * | 2013-04-16 | 2015-06-10 | 川渝中烟工业有限责任公司 | Cut tobacco drying technology method adopting HDT to reduce hydrocyanic acid release amount of cigarettes |
| CN105520185A (en) * | 2016-01-20 | 2016-04-27 | 长沙鑫迪电子科技有限公司 | Tobacco leaf baking equipment |
| DE102017120626A1 (en) * | 2017-09-07 | 2019-03-07 | Hauni Maschinenbau Gmbh | Conditioning of tobacco |
| FR3085385B1 (en) * | 2018-09-03 | 2021-04-02 | Remi Heliot | THIN LAYER MALTING PROCESS |
| EA202192248A1 (en) * | 2019-04-03 | 2021-12-15 | ДжейТи ИНТЕРНЕШНЛ СА | METHOD AND SYSTEM FOR PROCESSING TOBACCO |
| CN110720654B (en) * | 2019-11-05 | 2022-04-22 | 福建中烟工业有限责任公司 | Method for controlling moisture content of cigarette |
| CN111728258B (en) * | 2020-07-13 | 2022-05-03 | 广西中烟工业有限责任公司 | Pretreatment process for shredding tobacco flakes |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2105848A (en) * | 1935-04-11 | 1938-01-18 | Wurton Machine Company | Method for treating tobacco |
| GB1257444A (en) * | 1969-03-12 | 1971-12-15 | ||
| DE2103671C2 (en) * | 1971-01-27 | 1982-12-23 | Hauni-Werke Körber & Co KG, 2050 Hamburg | Process and system for conditioning tobacco |
| US4241515A (en) * | 1971-01-27 | 1980-12-30 | Hauni-Werke Korber & Co. Kg | Method and apparatus for conditioning tobacco |
| DE2402538C2 (en) * | 1974-01-19 | 1985-05-09 | Hauni-Werke Körber & Co KG, 2050 Hamburg | Method and device for conditioning tobacco |
| US3879857A (en) * | 1974-02-27 | 1975-04-29 | Amf Inc | Spiral moisture equaliser and method of using same |
| US4178946A (en) * | 1976-06-25 | 1979-12-18 | Philip Morris Incorporated | Apparatus and method for control of air relative humidity with reduced energy usage in the treatment of tobacco |
| US4202357A (en) * | 1978-10-27 | 1980-05-13 | Philip Morris Incorporated | Reordering expanded tobacco by water mist |
-
1993
- 1993-10-22 TW TW082108836A patent/TW296974B/zh active
- 1993-10-25 MY MYPI93002207A patent/MY109619A/en unknown
- 1993-10-25 CA CA002109153A patent/CA2109153C/en not_active Expired - Fee Related
- 1993-10-27 ES ES93308562T patent/ES2144002T3/en not_active Expired - Lifetime
- 1993-10-27 EP EP93308562A patent/EP0595616B1/en not_active Expired - Lifetime
- 1993-10-27 DE DE69327631T patent/DE69327631T2/en not_active Expired - Fee Related
- 1993-10-27 TR TR00984/93A patent/TR27107A/en unknown
- 1993-10-27 SK SK1193-93A patent/SK281909B6/en not_active IP Right Cessation
- 1993-10-27 AT AT93308562T patent/ATE188846T1/en not_active IP Right Cessation
- 1993-10-27 CO CO93415790A patent/CO4230157A1/en unknown
- 1993-10-27 DK DK93308562T patent/DK0595616T3/en active
- 1993-10-27 PT PT93308562T patent/PT595616E/en unknown
- 1993-10-28 RO RO93-01457A patent/RO111821B1/en unknown
- 1993-10-29 NO NO933932A patent/NO304095B1/en not_active IP Right Cessation
- 1993-10-29 UA UA93002130A patent/UA29384C2/en unknown
- 1993-10-29 PL PL93300893A patent/PL172905B1/en not_active IP Right Cessation
- 1993-10-29 FI FI934821A patent/FI103373B1/en active
- 1993-10-29 HU HU9303088A patent/HU219164B/en not_active IP Right Cessation
- 1993-10-29 RU RU93049599A patent/RU2120217C1/en not_active IP Right Cessation
- 1993-10-29 BR BR9304433A patent/BR9304433A/en not_active IP Right Cessation
- 1993-10-29 BG BG98186A patent/BG62028B1/en unknown
- 1993-10-29 CN CN93120741A patent/CN1043183C/en not_active Expired - Fee Related
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- 1993-10-29 LV LVP-93-1174A patent/LV11096B/en unknown
- 1993-10-29 MX MX9306795A patent/MX9306795A/en unknown
- 1993-10-30 EG EG68893A patent/EG20133A/en active
- 1993-10-30 KR KR1019930022825A patent/KR100281931B1/en not_active IP Right Cessation
- 1993-11-01 AU AU50366/93A patent/AU679003B2/en not_active Ceased
- 1993-11-01 JP JP29751093A patent/JP3696260B2/en not_active Expired - Fee Related
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1994
- 1994-09-06 EE EE9400141A patent/EE03289B1/en not_active IP Right Cessation
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1998
- 1998-12-24 HK HK98115332A patent/HK1013785A1/en not_active IP Right Cessation
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2000
- 2000-03-29 GR GR20000400791T patent/GR3033102T3/en not_active IP Right Cessation
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