JPH0517839B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention is applicable to powders with a particle size of 100 to 200 μm, ranging from a sucrose single crystal with a particle size of about 10 to 40 μm.
The present invention relates to a continuous sucrose crystallization method and an apparatus therefor, which can produce crystals of sucrose consisting of a single crystal of about 1.0 m in size, depending on the intended use. [Prior Art] Conventionally, various methods have been established for manufacturing various refined sugar products by precipitating sucrose crystals from purified sucrose liquid, depending on the purpose. For example, Shiroshita, which has a solid content of about 90% by weight and consists of fine single crystals with a particle size of 40 μm or less, which is widely used in the food industry as a foundation (this Shiroshita can be solidified by drying or densifying it by an appropriate method) ) can be used by concentrating a sucrose solution containing about 8% starch syrup based on the solid content to a concentration of about 90% by weight, cooling and stirring as appropriate, and instantly producing a large amount of crystals. It is produced by generating nuclei, growing crystals, and desugarizing the mother liquor. The method for industrially producing the above-mentioned foundation powder is as follows. First, a sucrose solution containing 4-8% by weight starch syrup based on solid content is prepared, introduced into a concentrator and concentrated at atmospheric pressure to obtain a high-temperature concentrated sugar solution with a concentration of 88-90% by weight and a temperature of 118-120°C. shall be. Next, this sugar solution is introduced into a horizontal screw mixer, etc., and is rapidly cooled to generate a large amount of crystal nuclei, which is desugarized in the process of sequential feeding while stirring and mixing, and stabilized foundation-like whites are produced. Manufactured. In this case, rapid cooling generally requires forced cooling with a refrigerant. Alternatively, the most widely used refined sugar is
We produce Shiroshita consisting of a single crystal of 100 to 600 μm,
The product is made by drying the crystals that are separated from this Shiroshita using a centrifuge, but the Shiroshita used here is either a refined sugar solution or a refined sugar solution that has been repeatedly decanted one to several times and separated into honeydew. It is produced by a decoction operation in which sugar is introduced into a vacuum crystallizer and discharged after the stages of concentration, crystallization, crystal growth, and desaccharification. This sugar brewing operation is usually performed as follows. First, a sugar solution with a solid content concentration of 60 to 68% by weight is introduced into a vacuum crystallizer equipped with a steam heat exchanger, and heated and evaporated under vacuum to concentrate to a temperature of 50 to 55℃ and a concentration of 72 to 74% by weight. do. Next, heating is stopped or crystallization is performed under gentle heating conditions. Crystallization is an operation that generates crystals in an amount corresponding to the particle size of the final product, and involves introducing a foundation-like slurry containing a predetermined amount of crystals into a can, and adding powdered sugar to a slightly higher supersaturated state. There is a method in which the required amount of crystal nuclei is generated by the impact of injecting the crystal. The amount of crystal nuclei or fine crystal particles after crystallization is small compared to the sugar solution in the can, and their surface area is small, so there is a risk that new crystal nuclei will be generated in the supersaturated mother liquor. be. For this reason, water is introduced into the can to grow crystals while adjusting the degree of supersaturation, and the mother liquor is desaccharified to stabilize the white state. Next, start the crystal growth operation. This crystal growth operation involves introducing a sugar solution into a can, evaporating it by steam heating while maintaining the supersaturation degree of the mother liquor at around 1.2, growing crystals, and stopping the supply of sugar solution when a predetermined crystal grain size is reached. , the sucrose content in the mother liquor is discharged through a desaccharification operation that transfers as much of it as possible to crystals. In this case, fine crystals newly generated during crystal growth must be dissolved by appropriately introducing water into the can, and only the crystals generated during the crystal growth process must be grown. Furthermore, as a method for producing amorphous sugar, a method is used in which the sugar is concentrated in an open can at high temperature (120 to 130°C) to a concentration of 90% by weight or more, and then solidified by cooling and stirring. In Brazil, a concentrated liquid concentrated to a concentration of 93 to 94% by weight at atmospheric pressure (this concentrated liquid has a high temperature of 126°C or more due to an increase in the boiling point) is sent to a Peter crystallizer (stirring crystal assistant). There is also a method in which crystals are generated as the temperature decreases, and residual moisture is evaporated and solidified by the release of crystal energy. Alternatively, Japanese Patent Publication No. 55-9200 and Japanese Patent Application Laid-open No. 57-122759 disclose that high-speed shear stirring is performed on a supersaturated sugar solution that has been concentrated to the crystallization region under atmospheric pressure to generate crystal nuclei. A method of obtaining fine crystals of Danto size is disclosed. [Problems to be Solved by the Invention] However, in any case, the conventional methods have many problems that need to be improved, such as energy cost, high temperature treatment, equipment cost, and operability. For example, in the production of fondant-like white shavings,
The temperature of the concentrated sugar solution is adjusted to prevent the formation of natural crystals.
Must be kept below the saturation point. Additionally, because of its high concentration, the boiling point rises high, resulting in high-temperature treatment of approximately 120°C. During crystallization, equipment costs and running costs for heat exchange equipment and chilling units for forced cooling of this high-temperature sugar solution are large. Sensible heat loss when concentrating a sugar solution with a concentration of 70% by weight to produce fondant-like Shiroshita amounts to as much as 20% of the input heat. On the other hand, in the production of refined sugar Shiroshita, the number of crystals generated in the crystallization process is regulated using a vacuum crystallizer and the crystals are grown to the required crystal grain size, so the supplied sugar solution reaches the saturation point at the vacuum evaporation temperature. The following concentration (approximately 68% by weight)
The following is common. ), and to prevent new microcrystals from forming at each stage of roasting sugar.
The degree of supersaturation must be adjusted by introducing water as appropriate. Even in the case of caster sugar, which is the easiest to boil, this amount of water reaches 6 to 10% by weight of the amount of white sugar, and corresponds to 14 to 20% of the input heat. Further, the operation of the vacuum crystallizer is a stepwise operation of concentration, crystallization, crystal growth, and desugarization. Therefore, the operation is complicated and requires skill, and batch operations are generally performed. Automatic control is also a complicated control mechanism and requires precise adjustment.
Furthermore, the crystallized can for efficient roasting sugar is equipped with a stirrer to circulate the white sugar inside the can, and the crystallized sugar can ^is
Large-scale equipment equipped with a heat exchanger with a heat transfer area of ~4 m ² is required, and the equipment cost including accessory equipment is high. Alternatively, in the production of amorphous sugar, sugar solution is
In order to concentrate to a high concentration of 90% by weight or more, the sugar solution must be kept below the saturation point and must be concentrated at a high temperature of 120°C or higher. The degree of coloration of the sucrose solution progresses as the heating temperature and heating time increase.
Decrease the quality of the product. This is particularly noticeable when the invert sugar and non-sugar contents are high. Therefore,
There is a need for equipment that can process in the shortest possible time.
Processing sugar solutions with a low percentage of pure sugar poses problems. The present invention was proposed in view of these circumstances, and it improves thermal efficiency, enables short-time processing at low temperatures, and allows continuous production of high-quality white undercoats. We have developed a continuous sucrose crystallization method and equipment that can produce white sucrose with various average particle sizes depending on the application, from Dant size (particle size of 40 μm or less) to soft sugar size (particle size of 100 to 200 μm). The purpose is to provide. [Means for Solving the Problems] In order to achieve the above object, the sucrose continuous crystallization method of the present invention is such that a sucrose solution that has been concentrated in advance to a solid concentration of 80 to 86% by weight at a temperature higher than the saturation temperature, After rapidly reducing the pressure to cause an increase in concentration and a decrease in temperature due to self-evaporation, and instantaneously creating a supersaturated state and generating crystal nuclei, new crystal nuclei are naturally generated in the sucrose solution containing the crystal nuclei. In order to suppress
It is characterized by growing crystals while being kept warm or slowly cooled. Furthermore, the continuous sucrose crystallization apparatus of the present invention has an evaporation chamber in the upper part, which rapidly reduces the pressure of the sucrose solution to generate crystal nuclei, and also uses a stirrer to ensure that the generated crystal nuclei are sufficiently fluidized and mixed. The crystallization zone is equipped with a stirring/progressive mechanism that is continuous below the crystallization zone and suppresses the vertical mixing of the fluid and constantly and gently mixes and contacts the crystal nuclei and the sucrose solution. It consists of a crystal growth zone equipped with a heat exchanger to maintain an appropriate temperature and adjust the growth rate of crystals and the generation of fine crystals.
The present invention is characterized in that a detection device is provided at the bottom of the crystal growth zone. That is, in the present invention, first, the raw sugar solution is concentrated in as short a time as possible at a temperature that is kept below its saturation point, and immediately supplied to a vacuum can whose pressure is reduced to a predetermined degree of vacuum. Then, the sugar solution supplied into the vacuum can reaches the boiling point temperature at the above degree of vacuum (= the evaporation temperature of water corresponding to this degree of vacuum plus the boiling point increase corresponding to the concentration of the sugar solution). The sugar solution is rapidly cooled, and at the same time evaporation occurs corresponding to the temperature difference between the supplied sugar solution temperature and the cooled sugar solution, and the sugar solution concentration increases. This rapid increase in concentration and decrease in temperature instantaneously brings the sugar solution into a highly supersaturated state, generating crystal nuclei. The rate of crystal nucleus generation changes depending on the pure sugar ratio, but in the case of pure sucrose solutions, it increases rapidly when the degree of supersaturation reaches 1.5 or higher. Therefore, setting the degree of supersaturation is the first factor that determines the grain size of the white undercoat. That is,
It is determined by the temperature and concentration of the supplied sugar solution and the vacuum degree in the can (=temperature of the sugar solution in the can). The generated crystal nuclei rapidly grow in contact with the highly supersaturated mother liquor, become fine crystals, and move to the lower crystal growth zone. The mixed fluid of crystals and mother liquor causes the sucrose content of the mother liquor to precipitate on the crystal side over time, the crystals gradually grow, the mother liquor increases in sugar, and its supersaturation level decreases. When the supersaturation degree of the mother liquor becomes 1.2 or less,
The degree of generation of new crystal nuclei decreases, and the white state becomes stable. The downward flow under the white must be as perfect a piston flow as possible, and the crystals and mother liquor must be in a constant state of fluidity and mixing. When producing foundation-sized Shiroshita with a high pure sugar percentage according to the above-mentioned method, a large amount of crystal nuclei are generated in the crystallization zone with a high degree of supersaturation reaching 2.5 to 3.0. In other words, if the temperature of the supplied sugar solution is 90 to 110℃ and the concentration is 82 to 84% by weight, and the inside vacuum level is around 60mmHg (the sugar solution temperature is 50 to 60℃), the concentration will be 86 to 90% by weight due to self-evaporation. The degree of supersaturation reaches 2.0-3.0, and the density of the produced white material reaches 86-90. In this case, the total crystal surface area is large in the initial stage, the desugarization of the mother liquor proceeds rapidly, the occurrence of pseudocrystals (microcrystals newly generated during crystal growth) is small, and the operation is performed at a relatively high flow rate. can do. Further, under these conditions, heating or cooling is not performed during crystal growth unless it is particularly necessary, but it is also possible to heat the crystal before discharging, for example, in order to lower the viscosity. Shiroshita with a relatively large crystal grain size (grain size 100~200μ
When producing m), the amount of crystal nuclei generated must be controlled by lowering the degree of supersaturation in the crystallization zone. In the case of pure sucrose solution, a suitable amount of nuclei is generated in the crystallization zone with a degree of supersaturation of 2.0 to 2.5. At this time, since the degree of supersaturation is relatively low, if the generation of crystal nuclei is slow, the generation of nuclei can be promoted by shock seeding. By the way, in this case, since the total surface area of crystals generated in the crystallization zone is small, the rate of transfer of sucrose content from the mother liquor to the crystal nuclei generated in the crystallization zone is slow, and therefore the generation of pseudocrystals to some extent can be avoided. I can't.
Since the occurrence of pseudocrystals decreases as the crystal growth zone moves and the supersaturation level of the mother liquor decreases, the crystallization conditions must be set so that the pseudocrystals that occur at this initial stage also reach the required number of crystals. Bye. However, the crystal grain size distribution in the white undertone is determined by the state, amount, and timing of the occurrence of pseudocrystals. Therefore, when producing Shishita by such a method, the standard deviation value of the particle size distribution increases as the crystal grain size of Shishita increases. For the production of refined sugar, the above Shiroshita is 100~
An average particle size of 200 μm is appropriate in terms of quality. When producing Shiroshita with a relatively large crystal grain size, it is also possible to reduce the occurrence of pseudocrystals and adjust the grain size distribution by programming the temperature gradient of the crystal growth zone. For example, in the case of a sugar solution with a high percentage of pure sugar, the temperature of the supplied sugar solution is 100℃, the concentration is 84% by weight,
If the crystallization operation is performed at a vacuum level of 130 mmHg in the can, the temperature of the sugar solution in the can will be 64°C, the concentration will be 88% by weight, and the degree of supersaturation will be 2.5, and crystal nuclei will be generated. The temperature at the top of the crystal growth zone is kept at 64℃, and the temperature is lowered from the position where the supersaturation level is 1.2 or less to grow the crystals, and the supersaturation level is 1.1 to 1.2.
If crystal growth is maintained while maintaining the concentration, the concentration will be 88% by weight and the average particle size will be
It is discharged from the bottom in the form of a stable white layer of 100 to 150 μm. In the present invention, increasing the temperature of the crystallization zone (lowering the degree of vacuum) causes sensible heat loss corresponding to the difference from the discharge temperature, and in extreme cases, energy saving, which is one of the features of the present invention, occurs. It will lose its effectiveness. Therefore, it is preferable to suppress the concentration of the supplied sugar solution to 86% by weight or less. Furthermore, if the concentration of the supplied sugar solution is less than 80% by weight, the concentration of the resulting white undercoat will be too low. In the method of the present invention, the concentration of the supplied sugar solution is preferably in the range of 80 to 86% by weight,
More preferably, it is 82 to 84% by weight. The apparatus for carrying out the present invention includes a sugar solution concentration can,
It consists of a crystallization device and a white discharge device. The sugar solution concentrator is preferably a one-pass type that completes evaporation in a short time, and there are no particular restrictions on the model, but if an evaporative vapor recompression type is adopted, it can be used as a continuous crystallization system that does not require steam energy. Become. Furthermore, due to its thixotropic nature, it is desirable to keep the liquid under stirring and mixing as much as possible until the discharge is complete. If so, it can be discharged using a white-bottom pump. The residence time of the sugar solution in the device is adjusted by the discharge rate. [Action] Solids concentration 80-86% by weight at temperatures above saturation temperature
When a concentrated sucrose solution is rapidly depressurized, the concentration increases due to self-evaporation and the temperature decreases, resulting in instantaneous supersaturation and the generation of crystal nuclei. At this time,
The number of crystal nuclei generated can be adjusted by selecting the degree of vacuum. Next, by keeping warm or slowly cooling to suppress the natural generation of new crystal nuclei and grow the crystals, depending on the number of crystal nuclei generated and the concentration of the supplied sucrose, the sizes range from foundation size to commercially available soft sugar size. Until then, white undercoats with various particle sizes are produced. [Example] Example of continuous sucrose crystallization device An example of a continuous sucrose crystallization device to which the present invention is applied will be described below with reference to the drawings. As shown in FIG. 1, the continuous crystallization apparatus of the present invention is configured as a vertical cylindrical crystallization can, and has a large-diameter evaporation chamber 1 at the top, and a crystallization zone below the evaporation chamber 1. 2, and a crystal growth zone 3 continuous below the crystallization zone 2. The evaporation chamber 1 is evacuated from the exhaust port 4 by a vacuum pump via a condenser (not shown), and the degree of vacuum is adjusted. Further, the evaporation chamber 1 has a capacity capable of smoothly discharging self-evaporated steam and preventing entrainment of the self-evaporated steam due to rapid pressure reduction of the supplied sugar solution. A stirrer 5 is installed in the crystallization zone 2 to mix and stir the sugar solution supplied from the concentrated sugar solution supply port 20. Since the sugar solution supplied to the crystallization zone 2 is violently flowing up and down due to rapid self-evaporation, there is no problem even if the stirrer 5 is rotated at a low speed. On the other hand, in the crystal growth zone 3, a plurality (5 stages in this embodiment) of screw-type stirring blades 6 are installed to prevent vertical mixing of the fluid and obtain a smooth downward flow. A plurality of curved stirring blades 7 (four stages in this embodiment) are installed between the stirring blades 6 to stir and mix the center portion and the outer peripheral portion. The screw-type stirring blades 6 at the bottom stage keep the viscosity of the thixotropic fluid at its lowest level, while
It plays a role in smooth discharge. It is preferable that each of the stirring blades 6 and 7 be kept in constant fluid contact, rotate at a low speed that does not cause vertical turbulence, and be driven by a variable speed motor of about 0 to 20 revolutions/minute. In this embodiment, the stirrer 5 in the crystallization zone 2, the stirring blade 6 in the crystal growth zone 3,
7 are attached to the same shaft 8, and are rotationally driven by an agitator electric motor 9 provided at the top. A heat insulating jacket 10 serving as a heat exchanger is attached to the outer periphery of the crystallization zone 2 and the crystal growth zone 3. The thermal jacket 10 is divided into three parts: an upper jacket 10a, a middle jacket 10b, and a lower jacket 10c. It has an inlet nozzle 11 and an outlet nozzle 12 for water. Here, in order to maintain the crystallization temperature, the temperature of the insulating water sent to each compartment jacket 10a, 10b, 10c may be the same temperature, but if the grain size of the white bottom produced is large, the crystallization temperature is relatively high, and in the initial stage, the temperature of the warm water in the upper section jacket 10a is adjusted in order to maintain the crystallization temperature for a certain period of time or to moderate the temperature drop gradient. Further, when the white undertone concentration is high and the viscosity is high, the temperature of the warm water in the lower section jacket 10c is increased. The bottom of the crystal growth zone 3 is shaped like an inverted cone, and a discharge port 13 is provided at the bottom thereof. Therefore, the produced white matter is transferred to this discharge port 1 by the screw-type stirring blade 6 at the bottom of the crystal growth zone 3.
Sent out from 3. As a discharge mechanism, as shown in the figure, a mechanism that includes two vacuum mixers 14 and alternately and continuously discharges with compressed air can be considered, but is not limited to this. degree is
If it is below 160mmHg, it can be discharged directly with a high viscosity slurry pump. The tower height of the above-mentioned continuous crystallization device is determined by the device capacity, manufacturing conditions, etc., but is typically determined by the liquid height/
It is appropriate that the column diameter is approximately 2.0 to 5.0. Note that here, the liquid height is the height of the liquid level of the sugar solution, and the tower diameter is the inner diameter of the apparatus in the crystallization zone 2 and the crystal growth zone 3. When a fixed amount of sugar solution concentrated to a predetermined concentration is supplied by the concentrator from the concentrated sugar solution supply port 20 of the continuous crystallization apparatus configured as described above, the sugar solution is rapidly depressurized in the crystallization zone 2 and becomes self-sustained. Evaporation and temperature drop occur, resulting in a supersaturated state and the generation of crystal nuclei. The steam generated by the self-evaporation is discharged to the outside through an evaporation chamber 1 for reducing pressure. When crystal nuclei are generated, the self-evaporation gradually subsides, and then the crystal nuclei are transferred to the crystal growth zone 3 by the screw type stirring blades 6 and the curved type stirring blades 7. The crystal nuclei in this sugar solution are in this crystal growth zone 3.
The particles grow as they gradually move downward, and are discharged from the discharge port 13 at the bottom by the vacuum mixer 14 in the form of white grains of a predetermined particle size. In the crystal growing zone 3, the outer periphery is covered with a heat insulating jacket 10.
Since a predetermined temperature gradient is formed by covering the sugar solution, new fine crystals will not be generated in the sugar solution. An example of a continuous sucrose crystallization apparatus to which the present invention is applied has been described above.Next, an experimental example in which various types of Shiroshita were produced using the continuous crystallization apparatus shown in FIG. 1 will be described. Experimental Example 1 A refined sugar solution was concentrated to a temperature of 90° C. and a concentration of 84% by weight, and the concentrated sugar solution was supplied to a continuous crystallization apparatus set at a vacuum degree of 40 mmHg. Crystallization temperature 48°C, residence time in the apparatus 20 minutes, upper section jacket 10a and middle section jacket 10
Temperature of b is 50℃, temperature of lower section jacket 10c
The temperature was set to 60°C, and the viscosity of the white undercoat produced was lowered and discharged. The discharged Shiroshita was a creamy fondant with a pleasant texture consisting of very fine crystals, and it did not solidify even after being stored in a sealed container at 18℃ for one month, with only a slight honey layer on the surface. Almost no changes were observed from the state at the time of manufacture. The refined sugar solution used and the resulting white brix Bx, pure sugar rate, reducing sugar rate, ash content, color value, and crystal grain size were investigated. In addition, Brix Bx was dissolved by diluting the sugar solution and Shiroshita twice, and was measured at 20°C using a Shugar refractometer. In addition, the pure sugar rate is sugar content /
Bx, color value (AI) of the sample is Bx50±0.2, PH7
After adjusting the absorbance at 420 nm using a spectrophotometer, the absorbance was determined using the following formula. Color value (AI)=1000×(−logT _420on )/l×C Here, l is the length of the cell used, and C is the sugar concentration (g/ml) of the material determined from Bx. Grain size was measured with a micrometer under a microscope. Reducing sugar and ash content are values per Bx. The results are shown in Table 1.

[Table] Experimental Example 2 A refined sugar solution was concentrated to a temperature of 105°C and a concentration of 83.5% by weight, and this concentrated sugar solution was supplied to a continuous crystallization device with a vacuum degree of 160 mmHg. Crystallization temperature 66℃, upper section jacket 10a64
℃, middle section jacket 10c55℃, lower section jacket 10c65℃, residence time in the device
Shiroshita was discharged in 35 minutes. The temperature inside the device is the crystallization section 66.
The temperature at the middle part was 64°C, the bottom part was 65°C, and the temperature at the bottom of the discharge was 65°C. Next, place this white bottom into a basket with a diameter of 20 cm.
Pour 0.6 into a centrifuge at 3000 RPM and separate for 4 minutes. Bx.82, 10 ml of Visco with a conversion rate of 90%.
After spreading it over the entire surface, the centrifuge was immediately stopped and the sugar inside the basket was scraped off to obtain 458 g of sugar. The solids recovery rate of this sugar was 52%. This sugar was mixed and air-dried to a moisture content of 0.8%, and the product obtained by sieving the corn sugar through a wire mesh with an opening of 4 mm had a product similar in appearance and texture to fine refined white sugar. The refined sugar solution used, the obtained white sugar and sand syrup, and commercially available white sugar for comparison were examined for Brix Bx, pure sugar percentage, reducing sugar, ash content, and color value. The results are shown in Table 2.

[Table] In addition, the obtained Shiroshita is made into honey without adding Visco,
The particle size distribution of the mixed and dried sugar was examined using a sieve with a 0.5 mm opening to remove lumps.
The results are shown in Table 3. In the table, MA is the average particle size, which is the opening of the sieve through which 50% of the sample passes. CV is a coefficient of variation, and is expressed as CV=standard deviation of particle size/average particle size.

[Table] Experimental example 3 A sugar solution containing decoction molasses from the refined sugar process was heated to a temperature of 105
℃ to a concentration of 84.0% by weight, and the concentrated sugar solution was supplied to a continuous crystallization apparatus with a vacuum degree of 120 mmHg. Crystallization temperature 58℃, upper circular jacket 10a60
℃, middle section jacket 10c50℃, lower section jacket 10c60℃, residence time in the device
Shiroshita was discharged in 40 minutes. The temperature inside the device is the crystallization section 62.
℃, the middle part was 56°C, the bottom part was 52°C, and the temperature at the bottom of the discharge was 56°C. Next, this Shiroshita was put into the same centrifuge as in Example 2, and when it was separated for 6 minutes,
15 ml of Bx.82 with a conversion rate of 90% was sprinkled over the entire surface, the centrifugation was immediately stopped, and the sugar inside the basket was scraped off to obtain 464 g of sugar. The solids recovery rate of this sugar was 52.5%. This sugar was mixed and air-dried to a moisture content of 1.4%, and the product obtained by sifting the corn sugar through a wire mesh with an opening of 4 mm had a product similar in appearance and texture to samuna sugar. The refined sugar solution used, the obtained Shiroshita and sugar, and commercially available brown sugar for comparison were examined for Brix Bx, pure sugar percentage, reducing sugar, ash content, and color value. The results are shown in Table 4.

[Table] In addition, the obtained Shiroshita is made into honey without adding Visco,
The particle size distribution of the mixed and dried sugar was examined using a sieve with a 0.5 mm opening to remove lumps.
The results are shown in Table 5.

〔Effect of the invention〕

As is clear from the above explanation, according to the method of the present invention, all the sensible heat needed to keep the pre-concentrated sucrose solution below the saturation point is used for self-evaporation, so the energy saving effect is extremely high. big.
Further, according to the method of the present invention, it is possible to obtain a highly concentrated white undercoat. For example, when a sugar solution with a concentration of 82% by weight is crystallized at a temperature of 110°C and a vacuum degree of 40 mmHg inside the can,
The concentration increase reaches as much as 7%, and it is possible to produce 89% by weight Shiroshita. Furthermore, according to the method of the present invention, depending on the setting of conditions, the particle size (particle size of 40 μm or less)
Soft sugar size (particle size 100~
It is possible to manufacture products with a thickness of up to 200 μm), and it is also possible to directly commercialize them as foundationants.
In addition, it is also possible to turn Shiroshita into amorphous sugar by drying methods such as spray drying or vacuum drying, and then to make products by sizing and granulating it, or to produce refined sugar by separating Shiroshita into honey. be. Furthermore, since the method of the present invention allows low-temperature treatment, there is almost no coloring during concentration and crystallization, and it is possible to obtain a white undercoat of excellent quality. In particular, when manufacturing amorphous sugar, additives such as various sweeteners, minerals, vitamins, amino acids, flavorings, and colorants are occluded within the amorphous structure, but in this case, they are also decomposed by heat or There is no risk of deterioration and it is possible to produce multi-purpose sugar products. On the other hand, according to the continuous crystallization apparatus of the present invention, continuous operation is possible by simply controlling the temperature and concentration of the supplied sugar solution, the degree of vacuum inside the can, the temperature of the water supplied to the heat insulating jacket, and the discharge speed, greatly improving productivity. In addition, automatic control of the device is easy. Additionally, the equipment of the present invention requires approximately half the equipment capacity per production volume compared to conventional vacuum crystallizers, and does not require a large heat exchanger, so equipment costs can be reduced. be.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing an example of a continuous sucrose crystallization apparatus to which the present invention is applied. DESCRIPTION OF SYMBOLS 1... Evaporation chamber, 2... Crystallization zone, 3... Crystal growth zone, 5... Stirrer, 6... Screw type stirring blade, 7... Curved stirring blade, 10... Heat insulation jacket, 13... …Vent.

Claims (1)

[Claims] 1. Solids concentration 80-86 at a temperature higher than the saturation temperature in advance
A sucrose solution concentrated to % by weight is rapidly depressurized to cause an increase in concentration and a decrease in temperature due to self-evaporation.
After instantaneously generating crystal nuclei in a supersaturated state, in order to suppress the spontaneous generation of new crystal nuclei in the sucrose solution containing the crystal nuclei, the crystals are grown while being kept warm or slowly cooled. Characteristic continuous sucrose crystallization method. 2. A crystallization zone that has an evaporation chamber at the top, rapidly reduces the pressure of the sucrose solution to generate crystal nuclei, and is equipped with a stirrer to ensure that the generated crystal nuclei are sufficiently fluidized and mixed; Continuing below the zone, there is a stirring/progressive mechanism that suppresses the vertical mixing of the fluid and constantly and gently mixes and contacts the crystal nuclei and the sucrose solution, and maintains an appropriate temperature in stages in the vertical direction to control the growth rate and fineness of the crystals. 1. A continuous sucrose crystallization apparatus, comprising a crystal growth zone equipped with a heat exchanger for regulating the generation of crystals, and a detection device provided at the bottom of the crystal growth zone.