PL172905B1 - Method of controlling moisture content in organic materials - 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

The present invention relates to a method of controlling the moisture content of organic materials such as pharmaceuticals and agricultural produce, including fruit, vegetables, grains, coffee and tea.

The way in which the moisture content of the tobacco is changed can have a lasting effect on the physical, chemical and subjective properties of the final product. Accordingly, methods used to effect changes in the moisture content of tobacco or other organic materials are of importance.

The reordering of expanded tobacco is a specialty process. Typically, the tobacco resulting from the depressurization process will have a moisture content of less than 6%, often less than 3%. At such a low moisture content, tobacco is very prone to breaking. Moreover, the expanded structure collapses during reordering, that is, it partially or fully reverts to a non-expanded state. This sinking causes a loss of filling power, thereby reducing the benefit of the expansion process.

Various methods of reordering expanded tobacco were used. The best known method is to subject the tobacco to a jet of water, typically while tumbling the tobacco in a rotary cylinder. The next way is to use saturated steam as an ordering agent. Yet another method is to blow high humidity air through a moving tobacco bed on a conveyor, as shown in US Patent No. 4,178,946.

None of the above methods have been found to be entirely satisfactory for use with expanded tobacco. The tumbling of the tobacco in the spray cylinder breaks the brittle, expanded tobacco. Direct contact with water causes the expanded tobacco structure to collapse. The reorganizing water vapor also causes the expanded tobacco structure to collapse. While this may be partly attributed to the high temperatures in the surrounding water vapor, exposure of the expanded tobacco to any gaseous environment in which water condenses occurs, such as steam or a highly humid air environment, also causes the tobacco to sink.

One method used to avoid these difficulties is to place the dry, expanded tobacco in the air-containing chamber at the desired humidity level, and allow the tobacco in the chamber to equilibrate within 24 hours to 48 hours. The air velocity through the chamber is very low, usually not greater than about 0.13 m / s. This procedure causes little or no collapse of the expanded tobacco structure. However, the long periods required, namely 24 to 48 hours, limited the use of this procedure to laboratory purposes only.

Attempts have been made to reduce the holding time needed for such balancing methods by increasing air velocity. These attempts have been unsatisfactory due to the inability to replicate the maintenance of filling power experienced with slow laboratory equilibration, the size of the conveyors needed to convey the tobacco to accommodate the long residence times needed, the non-uniformity of the moisture content of the tobacco product exiting such conveyors and the occurrence of fires in such units. as described in US Patent No. 4,202,357.

The use of desiccation as a moisture control agent during tobacco processing is just as important as it is in reordering. During the drying of the tobacco, both physical and chemical changes can occur which degrade the physical and subjective quality of the product. Therefore, the method of drying the tobacco is of particular importance.

There are two types of drying equipment typically used in the tobacco industry: rotary dryers and belt or screen dryers. Pneumatic type dryers are also sometimes used. The particular type of dryer is selected according to the desired drying operation. For example, belt or sheath dryers are typically used for strand tobacco and rotary dryers are used for cut tobacco. Both rotary and belt dryers are used to dry steam streams.

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In the belt dryer, the tobacco is spread over the perforated belt and air is directed either from above or below through the belt and the tobacco bed. There is often inconsistent drying of the tobacco due to the flow of drying air through channels in the bed, allowing local bypass of the tobacco.

Most rotary dryers used in the tobacco industry are lined with steam guide coils and may act as direct or indirect heat dryers depending on whether the heat is externally or internally applied to the tobacco dryer shell. Moreover, they can be activated either concurrently when the tobacco and air are flowing in the same direction or in the opposite direction when the tobacco and air are flowing in opposite directions. Rotary drying must be carefully controlled to avoid overdrying, which causes both chemical changes and undesirable breakage through rotation. Additionally, if drying occurs too quickly, an impermeable layer may form on the outer surface of the tobacco, making it difficult for moisture to diffuse from the inside of the tobacco to the surface. The formation of such a layer slows down the drying rate and causes uneven drying.

The use of a rotary or belt dryer to dry the tobacco can cause a thermal treatment that produces chemical and physical changes to the tobacco. While these changes are not always undesirable, they are caused by the removal of water from the tobacco. In common tobacco applications, the need to dry the tobacco in a limited amount of time induces a thermal treatment from the drying step, preventing the optimization of the heat treatment beyond the process constraints imposed by drying.

The present invention relates to a method of controlling the moisture content of organic materials, in which a bed of organic material is formed on a conveyor by depositing the material in multiple layers, and then contacting the organic material on the surface of the bed with an air stream with a relative humidity close to that of the organic material under equilibrium conditions. . The air flows from layer to layer along a path in a direction substantially opposite to the direction of movement of the organic material, whereupon the relative humidity of the air stream in contact with the organic material at the surface of the bed increases. In the method of the embodiment, the humidity of the organic material is also increased, and the relative humidity of the air stream is kept close to the equilibrium conditions of the organic material until the appropriate moisture content of the organic material is obtained. The air stream is dehydrated and the material is irrigated as the air flows substantially in the opposite direction to the flow of the organic material bed.

Preferably, the temperature of the organic material is below 311K before it is brought into contact with the air stream, and the organic material has an initial moisture content of from about 1.5% to about 13%, and particularly from about 1.5% to about 6%.

The air stream in contact with the organic material has a relative humidity of about 30% to about 64% at a temperature of about 294 K to about 322 K.

In the process of the invention, the organic material is tobacco, particularly puff tobacco, cut tobacco, whole leaf tobacco, cut or broken tobacco, stalks, processed tobacco or any combination thereof.

The organic material contacts the air flow at a velocity of about 0.23 m / s to about 1.22 m / s by directing the air flow either up or down through the bed of organic material, or by directing the air flow both downward. and up through the bed of organic material.

The organic material is hygroscopic, and selected from the group consisting of fruits, vegetables, grains, coffee, pharmaceuticals, tea, and any combination thereof.

The conveyor used in the solution is a spiral conveyor and the air stream is passed essentially through successive layers.

The invention also relates to a method of controlling the moisture content of organic materials, wherein a bed of organic material is formed on a conveyor by depositing the material in multiple layers. The organic material is then contacted with a stream of air flowing from layer to layer in a substantially transverse direction

172 905 opposite to the flow direction of the organic material bed. The relative humidity of the air stream is close to or less than that of the organic material at equilibrium conditions. The relative humidity of the air stream in contact with the organic material is then lowered, also reducing the moisture content of the organic material, while the relative humidity of the air stream in contact with the organic material is kept close to or below that of the organic material under equilibrium conditions until a complex moisture content is reached. the moisture content of the organic material. The organic material gradually dehydrates and the air flow gradually irrigates as the air flows substantially in the opposite direction to the flow of the bed of organic material.

Preferably, the temperature of the organic material is below about 311K before it is brought into contact with the air stream, and the organic material has an initial moisture content of from about 1.5% to about 13%, and preferably from about 1.5% to about 6%.

The organic material is tobacco, preferably puffed tobacco, cut or unpolluted tobacco, whole leaf tobacco, cut or broken tobacco, stalks, processed tobacco or any combination thereof.

Additionally, the organic material is preheated to a temperature of from about 311 K to about 394 K before the bed of organic material is formed on the conveyor, preferably the temperature of the organic material is below 394 K or below 311 K before contacting it with the air stream.

Prior to the step of contacting the organic material with the air stream, the organic material has a moisture content of from about 11% to about 40% and the air stream in contact with the organic material has a relative humidity of from about 20% to about 60% at a temperature of about 294 K to about 40%. about 322 K, and preferably the temperature of the air stream is from about 297 K to about 394 K.

The organic material is contacted with the air stream flowing at a speed from about 0.23 m / s to about 1.22 m / s, the air stream being directed up or down through the bed of organic material, or both up and down through organic material bed.

The organic material is hygroscopic with the hygroscopic organic material being fruit, vegetables, grains, coffee, pharmaceuticals, tea, and any combination thereof.

The conveyor used in the solution is a spiral conveyor and the air stream is passed essentially through successive layers.

The present invention has the advantage that tobacco or other suitable moisture absorbing agricultural products, including fruit, vegetables, grains, coffee and tea, can be cleaned or dried with little or no breakage, even with brittle tobacco emerging from the expansion process. . It further has the advantage of reordering the expanded tobacco with little or no loss of expanded tobacco structure and allows the tobacco or other suitable hygroscopic organic material to be dried at approximately atmospheric pressure, for example, without the use of a vacuum and at the selected temperature. can be controlled during the process to an extent not achievable with conventional tobacco drying methods.

In the preferred method of using the invention, changes in the moisture content of tobacco or other suitable organic materials are brought about by contacting the tobacco with air having a well controlled relative humidity above or below the equilibrium relative humidity of the organic material with which it is in contact. The relative humidity of the air increases or decreases continuously as needed during processing to maintain a controlled difference between the relative humidity of the air and the relative humidity of the equilibrium of the organic material with which it is in contact. Accurate, continuous control of the relative humidity enables the rate of moisture mass transfer between the organic material and the environment to be controlled so that structural changes to the tobacco are minimized. Utilizing relative humidity as the main driving force for mass transfer of moisture enables independent control of the heat treatment.

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This process can be carried out in series or continuously. Moreover, the process can be carried out without the use of rotary cylinders and the resulting breakage.

The subject of the invention will be illustrated in the drawing, in which: Fig. 1 shows a diagram of the relationship of the relative air humidity (RH) in percent in relation to the moisture content of tobacco or OV, Fig. 2 - a schematic diagram of a laboratory device for reordering hygroscopic organic material according to the invention by limiting the relative air humidity over a certain time, fig. 3 - a fragment of a view of an exemplary device for continuously implementing the invention, fig. 3a - a section of a part of the spiral conveyor shown in fig. 3, showing the path of air flow in relation to of the path of hygroscopic organic material, Fig. 4 is a schematic diagram of an alternative device suitable for carrying out the invention on a continuous basis, Fig. 5 is a block diagram illustrating the application of the invention to an ordering method, and Fig. 6 is a typical course of relative humidity RH of air in the vicinity of tobacco versus time. will get while tidying up in the device of Fig. 3.

The present invention relates to methods of controlling the moisture content of tobacco or other suitable hygroscopic organic material such as pharmaceutical and agricultural products including fruits, vegetables, grains, coffee and tea while minimizing breakage, changes in the physical structure, or thermally triggered changes in the chemical composition of the tobacco intended for use. machining. More particularly, the present invention relates to the use of humidity controlled air to either organize 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 and continuously increasing or decreasing the relative humidity of the air in contact with the tobacco or other suitable hygroscopic organic material as needed. In this way, moisture transfer is controlled, allowing other process variables such as temperature, air velocity, and air pressure to be optimized separately.

Two commonly used parameters characterizing the physical structure of tobacco are the cylindrical volume (CV) and the specific volume (SV). These measures are of particular importance in determining the benefits of this method for the ordering of tobacco.

The characteristic quantities discussed below will be described in more detail below.

Cylindrical volume (CV).

Tobacco filler weighing 20 grams when un-swollen or 10 grams when swollen is placed in a 6 cm diameter cylinder, model No. DD-60, designed by Heinr. Borgwaldt Company, Heinr. Borgwaldt GmbH, Germany. A piston weighing 2 kg in diameter was placed on the tobacco in the cylinder for 30 seconds

5.6 cm. The resulting compressed tobacco volume was read and divided by the weight of the tobacco sample to determine the cylinder volume as cm ³ / gram. The test determines the volume of a given weight of tobacco filler. The resulting filler volume is shown as the cylinder volume. This test is carried out under standard ambient conditions when the temperature usually reaches 297 K and a relative humidity of 60% RH, usually, unless otherwise stated, the sample is preconditioned in this environment for 24-48 hours.

Specific volume (SV).

Specific volume is a unit for measuring the volume occupied by solid objects such as tobacco using the Archimedes principle of fluid displacement. The specific volume of an object is determined by the inverse of its specific density. The specific volume is expressed in cm ³ / gram. Both the mercury porosity pycnometry and the helium pycnometry are suitable methods for making such measurements, and the results correspond to each other. If helium pycnometry is used, then a weighed tobacco sample, or as it is, dried at 373 K for 3 hours, or equilibrated, is placed in a Quantachrome Model 2042-1 penta-penta-penta chamber. The chamber is then removed and pressurized helium injected into it. The volume of helium displaced by the tobacco is compared with the volume of helium needed to fill the empty

172,905 sampling chamber. Tobacco volume is determined based on the basic principles of the ideal gas law. In the present application, unless stated otherwise, the specific volume was determined by using the same tobacco sample used for the determination of OV, i.e. tobacco dried after exposure for 3 hours in a circulating air oven controlled at 373K.

As used herein, the moisture content can be considered equivalent to the OV content because no more than about 0.9% by weight of the tobacco is volatile substances other than water. The kiln volatiles determination is a simple measurement of the weight loss of tobacco after exposure for 3 hours in a circulating controlled air kiln at 373K. The weight loss as a percentage of the initial weight is the kiln volatiles content.

The sieve test refers to a method of measuring the shred distribution of a sample of cut filler. This test is often used as an indicator of shred degradation during processing. A tobacco filler weighing 150 ± 20 grams if not swollen or 100 ± 10 grams if swollen is placed in a shaker. The shaker uses a series of 30.5 cm diameter circular sieve trays. The normal sieve sizes for the sieve trays are 6, 12, 20 and 35 mesh over a length of 2.5 cm. The device has a shaking distance (stroke) of about 2.5-1.25 cm and a shaking speed of 350 ± 5 rpm. The shaker agitates the tobacco for 5 minutes to divide the sample into ranges of various particle sizes. Each of the particle size ranges is weighted, thereby determining the particle size distribution of the sample.

Laboratory studies have shown that attempts to quickly rearrange the tobacco by exposing the tobacco to high humidity air causes CV losses. CV losses have also been shown to occur when condensation or over-moistening occurs inside the puffed tobacco bed. Condensation occurs when moist air comes into contact with tobacco that is below the dew point of the humid air. Over-humidification occurs when changes in moisture occur within the tobacco bed due to non-uniform exposure to moist air. Therefore, a suitable humid air reordering system must operate at a relatively low speed with proper control of the relative air humidity, air temperature, air flow and pressure through the tobacco bed. This may best be accomplished by gradually increasing the moisture content of the humid air passing through the tobacco such that the tobacco is exposed to an air stream that is close to equilibrium with the tobacco.

As shown in Fig. 1, the ABC line is the 297K isotherm of a typical expanded glossy tobacco. This isotherm relates the OV of the tobacco to the RH of the ambient air at equilibrium for a given temperature. Thus, point B indicates that at 297 K and 60% RH, the expanded tobacco sample will have an OV of about 11.7% after equilibration. The DEF line in Fig. 1 represents a typical RH profile for a tobacco that is rearranged according to this invention. The GEF line in Fig. 1 represents an alternative RH profile which also proved to be satisfactory. The HF line of Fig. 1 represents a path typical of the prior art such as laboratory reordering in a balancing chamber at very low air velocities. Line IJ of Figure 1 represents the use of the invention for drying tobacco.

Figure 1 shows that the rearrangement of the tobacco from an OV of about 6.5% when equilibrated with air at about 30% RH to an OV of about 11.7% when equilibrated with air at about 60% RH can be be accomplished by exposing it to air which has an increased humidity from about 40% RH in small increments over time until it reaches about 60% RH, rather than exposing it directly to air at 60% RH. Under these slowly changing conditions, the mass transfer between the airflow and the tobacco is relatively slow as the driving force is low and the expanded tobacco structure is maintained.

Rearrangement of expanded tobacco without loss of CV can also be accomplished by exposing the tobacco to air which has an increasing moisture content of about 40% RH in small increments over time and about 40 to about 60 minutes as long as

172,905 will not reach an RH of about 62%. This reduces the overall time required to complete the reordering process without significantly changing the structure of the expanded tobacco. Thus, the DEF and GEF lines of Figure 1 represent effective embodiments of the present invention in reordering tobacco.

As shown in Fig. 1, conditions close to equilibrium between the air flow and the tobacco are illustrated by the line segment EF and the line ABC. It should be noted that with an OV of tobacco below about 7%, the difference between the relative humidity of the air at equilibrium with the tobacco and the relative humidity of the humid air stream used for rearrangement can be quite large without adversely affecting the filler strength of the tobacco. It should also be noted that with a tobacco OV of about 7.5% to about 11.5%, the relative humidity of the reordering humid air stream used may be from about 2% to about 8% above the relative humidity of the air in equilibrium with the tobacco, with a greater deviation to equilibrium corresponding to the lower OV of the tobacco, without negatively affecting the filling power of the tobacco.

When using the present invention to dry tobacco, no measured loss of tobacco CV was observed. This was found to be the case even if the relative humidity of the drying air stream was well below the relative humidity of the air in equilibrium with the tobacco, that is, the relative humidity of the drying air stream was below the equilibrium conditions of the tobacco. In this regard, it should be noted that the line IJ of Figure 1 only illustrates one of the many possible paths that may be used in drying tobacco in accordance with the present invention.

The present invention may be applied to a batch or continuous process. In carrying out the batch reordering process, the relative humidity of the air stream in contact with the tobacco is increased over a period of time to cause a continuous increase in the moisture content of the tobacco. This may be accomplished in an environmental chamber such as that shown in Figure 2. The tobacco to be rearranged is placed, at a bed thickness of about 5 cm, in trays having mesh bottoms inside the environmental chamber such that a stream of controlled humidity air can pass through the tobacco. towards the bottom. The chambers have a size from about 0.6 m ³ and about 2.4 m ³ and have been used in many studies. The environmental chambers were equipped with a microprocessor, which allowed for a controlled increase in the air humidity conditions inside the chamber. Studies have been conducted in which dry expanded tobacco was rearranged from initial OV levels of about 2% to final Ov levels of about 11.5% by incrementally raising RH from initial levels as low as about 30% RH and as high as about 52% RH in the sections times from about 30 minutes to about 90 minutes, to final RH levels of between about 59% and about 65%. Air velocities in the range of about 0.26 m / s to about 1.1 m / s were used. RH and temperature measurements were monitored on a Thunder instrument model 4A-1. Air velocities were measured using an Alno Thermo model 8525 anemometer.

Studies in which relative humidities were raised from initial values as high as about 52% to final RH values as high as about 62% for as little as about 40 minutes resulted in rearrangement of tobacco with complete CV retention compared to similar reordered tobacco in an environmentally controlled room with air maintained at 60% RH and 297 K passing through the tobacco at low speed for 24 to 48 hours. Lifting in this manner was satisfactory for humid air velocities as high as about 1.1 m / s and temperatures from about 297 K to about 305 K. The swollen tobacco reordered in this manner exhibited minimal, if any, CV loss compared to swollen reordered tobacco. in an environmentally controlled room.

The present invention can also be operated as a continuous process most efficiently in a Frigoscandia self-loading spiral guide device as shown in Fig. 3. This device is a particularly modified GCP 42 model of a spiral cooler. The dry tobacco to be reordered enters the unit 10 on the conveyor 13, is guided through the unit 10 in a spiral geometry from the bottom to the

172 905 of the top of the spiral stack 14 as shown, and exits at the tobacco outlet 11 after reordering. Moist air is blown down through the tobacco from moist air inlet 15 to the bottom of helical stack 14 where it exits through moist air outlet 16 flowing substantially countercurrent to the tobacco flow direction, i.e. the main flow of moist air is from the top of the stack down through layers of the tobacco bed, and the tobacco moves up the helical path of the conveyor. A small portion of the moist air flows along the helical path of the conveyor from top to bottom in a truly counter-rotating pattern. These types of air flows are shown in Fig. 3a. This setup showed an effective representation of the increase in RH value obtained with the apparatus of Fig. 2.

Figure 3a is a cross-sectional view of a portion of the helical conveyor 14 shown in Figure 3, with the flow path of the air 20 and 22 relative to that of the tobacco bed 21 showing in detail. As shown in Figure 3a, the flow of air 20 and 22 takes place. from the top of the stack down. The tobacco flow is from the underside to the top of the unit and from right to left of Fig. 3a as the spiral conveyor 14 is moved upward. A major portion of the air flow 20, which is substantially opposite to the tobacco flow, through the tobacco bed layer 21 contacts with the tobacco bed at the level immediately below, while a small portion of the airflow 22 passes over the tobacco bed 21 in a direction opposite to the movement of the tobacco bed 21. This portion of the airflow 22 may later pass through the tobacco bed 21.

Essential to proper tooling in reordering is the use of a means to continuously increase the relative humidity of the air in contact with the tobacco as the tobacco OV increases. The Frigoscandia spiral collector conveyor, by virtue of its self-stacking characteristic, channels the major part of the airflow downward through the multiple layers of the conveyor (stack of conveyors) that convey the tobacco. By feeding tobacco to the bottom of the conveyor stack and humidified air to the top of the stack, the total flow of air and tobacco is substantially counter-rotating. This substantially counter-rotating flow creates a natural constant gradient of RH in the air contacting the titanium as the air is gradually dewatered as it moves down through the tobacco layers undergoing the reordering process. By judiciously selecting the conveyor belt speed, air and tobacco flow rates, and controlling the temperature and RH of the incoming air, conditions similar to those used in serial laboratory elevated reordering tests can be continuously approximated. For reordering about 68 kg / hr of expanded tobacco having 3% Ov, belt speeds of about 40 minutes to about 80 minutes hold time and air conditions of about 297 K to about 308 K at input relative humidities of about about 40 have been found to be suitable. 61% to about 64% at air flows of from about 30 m ³ / min. to about 75 m ³ / min. for complete reordering with no significant loss of CV or measurable tobacco breakage, using the modified Frigoscandia GCVP 42 spiral unit.

During the tobacco reordering, devices for recording the relative humidity over time, such as a Model 29-03 RH / temperature recorder, were passed through the Frigoscandia unit. These devices showed a steady increase in relative air humidity as the device was driven up the spiral stack, with initial RH records from about 35% to about 45% at the bottom of the stack where the tobacco is driest, to around 62% at the top of the stack where the tobacco is. completely rearranged.

Figure 6 shows a typical RH curve as a function of time obtained with the Rustrak unit. Figure 6 shows the percent RH of the air adjacent to a tobacco bed as a function of time. Tobacco with an initial OV of about 3% entered the helical reordering unit and was contacted with air having an RH of about 43% (Point A in Figure 6). Figure 6 shows that as the tobacco passed through the helical reordering unit, the IH-I reliance in the vicinity of the tobacco increased from about 43% to about 62% at the exit of the unit (Point B in Figure 6). The tobacco had an OV of about 11% after exiting the helical reorder unit. The RH of the air entering the spiral reordering unit was controlled to obtain reordered tobacco with no significant loss of CV.

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Other means of supplying air with increasing RH, such as the unit shown in Fig. 4, may also be used to implement the invention on a continuous basis. As shown in Figure 4, the tobacco enters the unit at the tobacco inlet 40 onto the conveyor 43 and exits at the tobacco outlet 41. Air is blown through the tobacco bed 42 at a continuously increasing relative humidity, either in an upward or downward flow, in numerous zones 44 to duplicate the lifting effect in the apparatus of FIG. 2. The lifting effect may be realized by feeding air from a single source in a serpentine manner from right to left in FIG. 4, producing a substantially counter-rotating air flow relative to the direction of travel of the tobacco. Thus, the air exiting from a given zone will be entering the next zone on its left hand side.

To carry out the method of the present invention, whole preserved tobacco leaf, cut or broken tobacco, puffed or unswollen tobacco, or selected tobacco parts such as stalks or processed tobacco may be treated. The method can be used in any or all of the above cases with or without the addition of flavoring substances. For the particular case of tobacco drying, it has been found that unswollen cut filler can be dried continuously, substantially at ambient temperature, by substantially counter-rotating flow through a modified Frigoscandia self-accumulating spiral conveyor, from a tobacco moisture content of about 21% OV to about 15% OV over a period of about one hour. In this case, air was entering the top of the unit at about 302.5 K and about 58% RH and was exiting at about 298 K and about 68% RH. Draining was performed with little or no heat treatment of the tobacco.

Alternatively, the method of the present invention can be used to dry tobacco having a temperature well above ambient temperature, for example tobacco at about 366.3 K to about 394 K. When the tobacco is dried within this temperature range, the RH and the temperature of the drying air are controlled. to obtain suitable conditions for carrying out the process according to the present invention.

In analogy to rearranging the tobacco, it was found that drying was best accomplished in the minimum amount of time by setting the final air humidity content lower than the humidity that would be needed to test the tobacco to the desired final air humidity level, thereby increasing the tobacco-air humidity gradient, and according to with driving force as for drying. Unlike the rearrangement process, the final moisture content of the air stream can be kept well below the level that is at equilibrium with the tobacco at the desired OV level after drying.

Example 1 To demonstrate the benefits of reordering dry, expanded tobacco by adding less water to it as compared to reordering in a spray cylinder, a sample of 20 grams of tobacco filler was placed in a sealed desiccator. This sample was saturated with liquid carbon dioxide and swollen in an expansion tower at 560.7 K. The OV of this expanded tobacco filler was 3.4%. It was calculated that approximately 1.89 grams of water was needed to increase this OV content of the sample to 11.5%. This amount of water was put into a small glass bottle with a rubber stopper having a glass tube with an inside diameter of 0.3 cm extending through it. The bottle was also sealed in a desiccator. After nine days, all of the water was adsorbed by the tobacco.

The tobacco was then tested and found to have an appropriate OV of about 11.5%. As used herein, the proper term is raised to the tobacco prior to equilibration in the environmental chamber with air maintained at 60% Rh and 297 K, passed through the chamber at low velocity for a period of 24 to 48 hours. This balancing process is basically used as a means to bring tobacco to a standard state prior to CV, SV and sieve measurements. After this standard equilibration, the tobacco reordered in the desiccator had a CV of about 9.5 cm ³ / gram and an SV of about 2.9 cm ³ / gram with an OV of about 11.6%. For comparison, when a second sample of the same tobacco was placed directly inside the balance chamber and matched by balancing

Under standard conditions, the equilibrium OV was about 11.3%, and the CV and SV values were about 9.4 cm ³ / gram and about 2.7 cm ³ / gram, respectively. A third sample of the expanded tobacco filler was reordered in the spray cylinder to a proper OV of about 11.5%. After equilibration, this sample had a CV of about 8.5 cm3 / gram and an SV of about 1.9 cm3 / gram with OV equilibrium of about 11.6%.

As can be seen from the data in Table 1, the tobacco sample that was reordered in the desiccator by slowly dispensing water showed a significant improvement in CV and SV balancing compared to the sample reordered by spraying. This sample also showed a slight improvement in CV and SV compared to the sample equilibrated directly in the equilibration chamber.

Table 1

A sample

Right

Balanced

OV (%) SV (cm ³ / g) OV (%) CV (cm ³ / g) SV (cm ³ / g)

Tower outlet 3, 4 thirty 11, 3 9, 4 Order- 11 1.8 11, 6 8.5 in cy- the cylinder Desiccator 11.5 2.7 11, 6 9, 5

2.7

1.9

2.9

A second set of experiments were performed using an environmental chamber to rearrange the 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, allowing controlled elevation of conditions inside the chamber.

Example II. About 1.3 kg of glossy tobacco saturated with liquid carbon dioxide and expanded under conditions similar to those described in Example No. 1 was placed in a bed about 5.08 cm thick inside the tray. This tray, having uniform sides and a mesh bottom, was placed inside the environmental chamber. The sample then rearranged over a 1 hour period with air at about 297 K with an initial RH of about 36% raised to a final RH of about 60%. The air movement was downwardly through the tobacco bed at a speed of about 0.24 m / s. This experiment was then repeated at time intervals of 3 hours, 6 hours, and 12 hours. The results, summarized in Table 2, indicate that for time periods increasing to about 6 hours, the rate of reordering affects the titanium CV and SV under these experimental conditions. The slower the rearrangement speed, the greater the observed CV and SV values.

In addition, the ordering of the invention results in CV values of at least about 1 cm3 / gram greater and SV at least 0.2 cm3 / gram greater than the values observed in the spray cylinder. However, it has been found that most of this yield is obtained by floating for as little as 1 hour.

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Table 2

Proper Balanced in an environmental chamber

OV (%) SV (cm3 / g) OV (%) CV (cm ³ / g) Tower outlet 3.10 3.06 11.33 9, 71 Spray cylinder 11.51 1, 61 11.37 8, 61 Lifting by 1 hour 10.83 1.85 11.38 9, 72 Lifting by Three hours 11.44 1.88 11.36 9, 81 Lifting by 6 hours 11.45 1, 90 11.30 9, 88 Lifting by 12 hours 11.41 1, 97 11.27 9, 89

Example ΓΠ. Laboratory studies were conducted on the effects of both ordering speed and temperature on tobacco CV and SV. Seven runs were carried out using carbon dioxide tobacco and expanded in a expansion tower at approximately 560.7 K. The expanded tobacco was reordered as follows:

(1) by equilibrating for 24 hours in an environmental chamber at 60% RH and 297 K with air moving through the tobacco at about 0.13 m / s;

(2) by spraying with water to increase the OV to about 7.5%, then equilibrating at 60% RH and 297 K for 24 hours, such as in (1);

(3) by spraying with water to increase the OV to about 7.5%, followed by final reordering in the spray cylinder;

(4) by spraying water to about 7.5% OV, then by applying humid air lift from an initial RH of about 46% to a final RH of about 60%; and (5) by blowing with moist air from about 46% RH to about 60% RH.

Cleanup with humid air was performed inside the environmental chamber

PGC equipped with a microprocessor to control lifting at selected intervals. The following conditions were selected:

(1) Lifting times: 30, 60 and 90 minutes;

(2) Air temperature: 297K and 308K;

(3) Air velocities: up through the tobacco bed at about 0.23 m / s, and down through the tobacco bed at about 0.88 m / s;

(4) Thickness of the tobacco bed; 5.08 cm.

The tobacco used for all rearrangements except the spray cylinder was collected at the tower outlet after swelling and sealed in double plastic bags prior to reordering. As a result, the tobacco cooled from about 366.3 K, the temperature of the tobacco at the exit of the expansion tower, to ambient temperature before

172 905 rearrangement. In ordering by lifting at about 308 K, the tobacco while still in the sealed bags was sufficiently pre-heated to avoid condensation upon contact with moist air prior to exposure to the elevated conditions. Data from these runs are summarized in Tables 3a through 3e.

Table 3a

Proper Sample Balanced

OV (%) SV (cm ³ / g) OV (%) CV (cm3 / g) X Outlet tower 3, 43 3, 02 11.131 9, 04 S Via nozzles only 8.06 2.14 11, 68 8, 66 C Through nozzles and cylinder 11.53 1.81 11.59 8.59 F By nozzles and lifted by 90 min. (46% RH to 60% RH, 297K) 11.27 1, 87 11.51 9, 01 H Via nozzles and lifted by 90 min. (46% RH to 60% RH, 297K) 10, 96 1, 98 11, 36 9, 48 I Sample H held 15 min. at 60% RH, 297K) 11.54 1, 95 11.56 9, 40 J By nozzles and picked up by 60 min. (46% RH to 62% RH, 308K) 10.37 2.38 11.28 9, 85 K Sample J held 15 min. at 62% RH, 308KC) 11, 17 2.26 11, 22 9, 88

172 905

Table 3b

A sample Right Balanced OV (%) SV (cm3 / g) OV (%) CV (cm ³ / g) X Tower outlet 3, 01 2.58 11, 34 9, 23 S Via nozzles only 7.51 2.13 11.39 8, 87 C Through nozzles and cylinder 11.86 1, 59 11, 64 8.07 F By nozzles and lifted by 60 min. (46% RH to 60% RH, 297K) 10.55 1, 64 11, 45 8.86 G Sample F held 15 min. at 60% RH, 297K. 11.56 1, 64 11, 42 8, 61 H By nozzles and lifting for 30 min. (46% RH to 60% RH, 297K) 10, 28 1, 97 11.27 8, 99 I Sample H held 15 min. at 60% RH, 297K 11.73 1.82 11.25 8, 61

172 905

A sample Table 3c Right Balanced OV (%) SV (cm ³ / g) OV (%) CV (cm ³ / g) A The discharge tower 1, 81 2, 78 11, 37 9, 23 B Raised for 60 minutes. (46% RH to 60% RH, 308K) 10, 91 1.86 11, 47 8.86 C Raised for 60 minutes. (46% RH to 60% RH, 297K) 10.53 2, 02 11, 28 9, 20 D Raised for 90 minutes. (46% RH to 60% RH, 308K) 10, 84 1, 99 11.45 8, 90 E Through nozzles 5, 39 2.37 11.25 8.71 F By atomizers and inserted directly at 60% RH, 308K for 30 min. 10, 80 1, 81 11.27 8.39 G By nozzles and lifted by 60 min. (46% RH to 60% RH, 308K) ' 10, 66 1, 85 11.23 8, 65 H Via nozzles and lifted by 90 min. (46% RH to 60% RH, 308K) 10.76 1, 82 11, 24 8, 62 And by sprayers and picked up by 60 min. (46% RH to 60% RH, 297K) 10, 65 1, 90 11.23 8.75 J By nozzles and picked up by 90 min. (46% RH to 60% RH, 297K) 10, 57 1, 87 11.38 8.74 K By atomizers and directly inserted at 60% RH, 297K for 30 min. 10, 73 1, 87 11.22 8, 64 L Through nozzles and cylinder 10, 98 1, 60 11.39 8.28

172 905

3d table

A sample Right Balanced OV (%) SV (cm ³ / g) OV (%) CV (cimtyg) Tl Outlet of the tower 2.83 3, 01 11, 92 9, 46 T2 Inserted directly at 60% RH, 297K, 30 min. 11.24 2, 27 11.77 8.08 T3 Raised for 90 minutes. (46% RH to 60% RH, 297K) 11, 08 2.24 11, 83 9.29 T4 Raised for 90 minutes. (30% RH to 60% RH, 297K) 9.77 2, 39 11, 85 9.43 S1 By nozzles 4.78 2.82 11, 66 8, 98 S2 By atomizers and inserted directly at 60% RH, 297K for 30 min. 11.10 2, 19 11, 64 8, 89 S3 By nozzles and lifted by 90 min. (46% RH to 60% RH, 297K) 10.54 2.25 11.27 9, 05 S4 By nozzles and lifted by 60 min. (46% RH to 60% RH, 297K) 10, 56 2.22 11, 73 9.03 S5 By nozzles and lifted by 30 minutes. (46% RH to 60% RH, 297K) 9, 74 2, 29 11, 67 9, 19 C Through nozzles and cylinder 10, 48 1, 95 11.81 8, 80

172 905

Table 3e

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The data tabulated in Tables 3a to 3e show that yields of from about 0.5 cm3 / gram to about 1 cm3 / gram for CV and from about 0.3 cm3 / gram to about 0.4 cm / gram for SV can be obtained by raising rearranging cooled tobacco, that is tobacco at about 297K to about 308K, compared to reordering in a hot tobacco spray cylinder exiting from the expansion tower. Raised reordering of OV directly from the tower outlet proved advantageous for the first tobacco spraying to increase its Ov content to about 7%, followed by ascending reordering. There was no significant difference in the CV or SV of the tobacco ordered by lift with humid air at an initial RH of about 46% compared to tobacco ordered by lift from the initial RH of approximately 30% or tobacco ordered by lift over a period of time or approximately 60 minutes. or about 90 minutes.

It has also been found that tobacco can be ordered either by moving air down through the tobacco bed at speeds from about 0.88 m / s to about 1.18 m / s or by air blowing up through the tobacco bed at speeds up to about 0.225 m / s, with no significant difference in CV or SV. Moreover, it was observed that the elevated rearrangement showed equivalent or better CV or SV values compared to the tobacco ordered by placing it directly into an environmental chamber at 60% RH and 297 K after exiting the expansion tower. Finally, it was observed that spraying with water to increase the OV to about 7.5% followed by lifting with humid air resulted in better CV and SV values compared to spraying followed by final clean-up in the spray cylinder.

Example IV. Research was conducted to determine the effects of air flow and air velocity on tobacco suspension, ducting and compaction. These studies were carried out with the use of two environmental PGC chambers. In both chambers, actual air movement was approximately 1.5 m ³ / min. The movement of air was upward through the tobacco bed in one PGC chamber and downwardly through the tobacco bed in the other. Tobacco samples having a thickness of 5.08 cm were placed inside 12.7 x 1.9 cm open top trays having mesh bottoms and 10.2 cm high solid sides. These trays were placed on shelves inside the environmental chambers. Air was forced through the shelves by covering the unoccupied surface of the shelves with cardboard and sealing any gaps with tape. The air velocity was varied by changing the number of sample containers through which the air passed. The tobacco used for this study was impregnated with carbon dioxide and swelled at about 561 K. The tobacco was rearranged in a first stage by spraying with water to about 8% OV immediately after expansion. The conditions inside the chambers during the study were controlled at about 297 K and about 60% RH. A blade anemometer and a hot wire anemometer were used to measure the air velocity. These instruments were placed directly above or below the samples to adequately measure the upward and downward motion of the air.

With the upward movement of the air, a slight lift of the direct tobacco was observed after the air was admitted at medium velocities, as low as about 0.13 m / s. Small air channels then formed and the tobacco was deposited. As a result of the formation of these channels, the air flow was very heterogeneous through the tobacco bed (about 0.11 m / s to about 0.225 m / s for an average flow of about 0.13 m / s). With increasing average air flows, there was more drainage, and at over 0.225 m / s, significant tobacco suspension and blown off resulted in significant drainage of the bed.

With the downward movement of air at all tested speeds, a certain compaction and corresponding reduction in air velocity were observed. This is shown in Table 4. At an initial speed of about 0.96 m / s, the thickness of the tobacco bed was densified by about 28%, and as a result, the air velocity through the bed was reduced to about 0.7 m / s. At initial air velocities of about 0.7 m / s or less, the compaction of the tobacco bed was about half that observed at about 0.96 m / s and the air flow through the tobacco bed was reduced to a much lesser extent.

172 905

Table 4

Influence of bed compaction on air velocity through the bed Air velocity (m / s) Bed thickness (cm)

Beginning End % Change Beginning End % Change 0, 96 0.7 27 5, 08 3, 69 28 0, 8 0, 72 11 5, 08 4.19 18 0.7 0, 67 6 5, 08 4.32 15 0.52 0, 49 6 5, 08 4.57 10 0, 22 0.21 5 5, 09 4.83 5

Based on the above examples, it has been determined that the expanded tobacco can be rearranged preferably by lifting under the following conditions:

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

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

(c) Temperature: from about 297 K to about 308 K;

(d) Airflow: upward at speeds up to about 0.225 m / s, or downward at speeds up to about 1.18 m / s.

Example 5 About 68 kg / hr. a mixture of glossy and burley tobacco saturated with expanded carbon dioxide as described in the above examples was passed through a cooling conveyor to reduce its temperature from about 366 K to about 302 K before being fed to a modified Frigoscandia Model GCP 42 self-assembly spiral unit. The tobacco flow through the spiral unit was carried out by from bottom to top. The air flow was from the top to the bottom of the unit, resulting in a substantially counter-rotating flow of tobacco relative to air. This arrangement gave rise to an increased rearrangement of the tobacco as a result of the continuous dehydration of the air through the tobacco. Tobacco entered the process at about 3% OV and exited at about 11% Ov. Equilibrated CV feed material was about 10.53 cm ³ / g and balanced if CV reordered material was about 10.46 cm 3 / g, indicating no significant loss of filling power of tobacco by the process of ordering, i.e. no statistically significant loss of filling power, determined by standard analysis of the variance procedure. In addition, there was no measurable reduction in tobacco particle size as determined by the sieve test during the reordering process.

Several experiments have been carried out using various grades of expanded tobacco at different tower temperatures, in which the tobacco has been ordered according to the process of the present invention. In each run, about 68 kg / hr of tobacco was reordered, based on the weight of the reordered tobacco, in the modified Frigoscandia self-accumulating spiral unit described in Example 5. The inlet air to the reorder was at a temperature of about 302 K and a relative humidity of about 62%. The air leaving the reordering unit was typically about 305 K to about 308 K and a relative humidity of about 40% to about 45%. As shown in Table 5, the tobacco ordered according to the method of the present invention showed no significant loss in filling power.

172 905

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172 905

Example VII. About 90.7 kg / hr of shiny tobacco having an OV of about 21.6% was fed to the modified Frigoscandia self-accumulating unit described in Example 5, operating as a drying unit. The tobacco flow through the spiral drying unit was from bottom to top. Air flow was from the top to the bottom of the unit, resulting in a substantially counter-rotating flow of tobacco relative to air. The tobacco is preferably dried to about 12.2% OV for about 60 minutes hold time, using air with an input temperature of about 308 K and an input RH of about 35%. The air leaving the dehumidification unit was about 301 K and about 62% RH. The tobacco entering and exiting the drying unit was cooled to a touch-judged temperature of about 297K, indicating that substantially no heat treatment of the tobacco had occurred. There was no change in the tobacco balance as a result of the drying process. This particular drying example was designed to minimize heat treatment. Similar drying results can be obtained by using higher temperatures to obtain a controlled degree of heat treatment.

While the invention has been shown and described with particular reference to the preferred embodiments, it should be appreciated that various changes may be made in form and detail without departing from the scope of the invention.

172 905

Fig. 2

AIR

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172 905

Fig. 3a

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Fig.1

Publishing Department of the UP RP. Circulation of 90 copies. Price PLN 4.00

Claims (33)

Patent claims A method for controlling the moisture content of organic materials, characterized in that the bed of organic material is formed on a conveyor by depositing the material in multiple layers, and then contacting the organic material on the surface of the bed with an air stream with a relative humidity close to that of the organic material under the conditions of equilibrium, with air flowing from layer to layer along the path in a direction substantially opposite to the direction of movement of the organic material, whereupon the relative humidity of the air stream in contact with the organic material on the surface of the bed increases, the humidity of the organic material increases, and the relative humidity of the stream the air is kept close to the equilibrium conditions of the organic material until the appropriate moisture content of the organic material is obtained, the air stream dehydrating and the material hydrating as the air flows substantially in the direction u opposite to the flow of the organic material bed. 2. The method according to p. The process of claim 1, wherein the temperature of the organic material is below 311 K before it is brought into contact with the air flow. 3. The method according to p. The method of claim 1, wherein prior to the step of contacting the organic material with a stream of air, the organic material has an initial moisture content of from about 1.5% to about 13%. 4. The method according to p. The method of claim 1, wherein prior to the step of contacting the organic material with a stream of air, the organic material has an initial moisture content of from about 1.5% to about 6%. 5. The method according to p. The method of claim 1, wherein the air flow in contact with the organic material has a relative humidity of about 30% to about 64% at a temperature of about 294 K to about 322 K. 6. The method according to p. The process of claim 1, wherein the organic material is tobacco. 7. The method according to p. The method of claim 6, wherein the tobacco is expanded tobacco. 8. The method according to p. The tobacco according to claim 7, wherein the tobacco is cut tobacco. 9. The method according to p. The method of claim 6, wherein the tobacco is puffed or unpolluted tobacco, whole leaf tobacco, cut or broken tobacco, stalks, processed tobacco, or any combination thereof. 10. The method according to p. The method of claim 1, wherein the organic material is contacted with the flow of air flowing at a speed of about 0.23 m / s to about 1.22 m / s. 11. The method according to p. The process of claim 1, wherein the organic material is in contact with the air flow, the air flow being directed either up or down through the bed of organic material, or both up and down through the bed of organic material. 12. The method according to p. The method of claim 1, wherein the organic material is a hygroscopic organic material. 13. The method according to p. The method of claim 12, wherein the hygroscopic organic material is selected from the group consisting of fruits, vegetables, grains, coffee, pharmaceuticals, tea, and any combination thereof. 14. The method according to p. The process of claim 1, wherein the conveyor is a spiral conveyor and the air flow is passed substantially through successive layers. 15. A method for controlling the moisture content of organic materials wherein the bed of organic material is formed on the conveyor by depositing the material in multiple layers and then contacting the organic material with a stream of air flowing from layer to layer in a direction substantially opposite to the flow direction beds of organic material, where the relative humidity of the air stream is close to or lower than the humidity of the organic material under equilibrium conditions, then the relative humidity of the air stream in contact with the organic material is lowered, also reducing the moisture content of the organic material, the relative humidity of the air stream being in contact with the organic material is kept close to or below the moisture content of the organic material under equilibrium conditions until the complex moisture content of the organic material is reached, the organic material being The air flow gradually dehydrates and the air flow gradually irrigates as the air flows substantially in the opposite direction to the flow of the bed of organic material. 16. A method according to any one of claims 1 to 16 The method of claim 15, wherein the temperature of the organic material is below about 311 K before it is brought into contact with the air flow. 17. The method according to p. The method of claim 15, wherein prior to the step of contacting the organic material with a stream of air, the organic material has an initial moisture content of from about 1.5% to about 13%. 18. The method according to p. The method of claim 17, wherein the organic material has an initial moisture content of from about 1.5% to about 6% prior to the step of contacting the organic material with the air flow. 19. The method according to p. 15. The process of claim 15, wherein the organic material is tobacco. 20. The method according to p. 19. The process of claim 19, wherein the tobacco is expanded tobacco. 21. The method of p. 19. The process of claim 19, wherein the tobacco is cut tobacco. 22. The method according to p. The method of claim 19, wherein the tobacco is puffed or unblown tobacco, whole leaf tobacco, cut or broken tobacco, stalks, processed tobacco, or any combination thereof. 23. The method according to p. The method of claim 15, further preheating the organic material to a temperature of from about 311K to about 394K before forming the bed of organic material on the conveyor. 24. The method according to p. The process of claim 15, wherein the temperature of the organic material is below 394K prior to contacting it with the air flow. 25. The method according to p. The process of claim 15, wherein the temperature of the organic material is below 311 K before it is brought into contact with the air stream. 26. The method according to p. The method of claim 15, wherein the organic material has a moisture content of from about 11% to about 40% prior to the step of contacting the organic material with the air flow. 27. The method according to p. The method of claim 15, wherein the flow of air in contact with the organic material has a relative humidity of from about 20% to about 60% at a temperature of from about 294 K to about 322 K. 28. The method of any one of claims 28 to The process of claim 15, wherein the temperature of the air stream is from about 291 K to about 394 K. 29. The method according to p. The method of claim 15, wherein the organic material is in contact with the air stream flowing at a speed of about 0.23 m / s to about 1.22 m / s. 30. The method according to p. The method of claim 15, wherein the organic material is in contact with the air flow wherein the air flow is directed up or down through the bed of organic material or both up and down through the bed of organic material. 31. The method according to p. The method of claim 15, wherein the organic material is a hygroscopic organic material. 32. The method according to p. The method of claim 15, wherein the hygroscopic organic material is fruit, vegetables, cereals, coffee, pharmaceuticals, tea, and any combination thereof. 33. The method according to p. The method of claim 15, characterized in that the conveyor is a spiral conveyor and the air flow is passed substantially through successive layers.