RU2146711C1 - Method of preparing seed material - Google Patents

Abstract

FIELD: sugar industry. SUBSTANCE: invention relates to seed materials used in sugar fillmass digestion process. Surfactant is added to saturated sugar solution prepared at 50 C to initiate crystallization to form fine crystals under vibration agitation in the course of cooling to 40-30 C. Crystal mass is subjected to precipitation centrifugation to separate concentrated suspension of crystals from intercrystalline solution. To that suspension is added surfactant, which is homogeneously distributed in bulk under vibration agitation. Resultant seed material is packed in cylindrical fluoroplastic holders wherein solid- like structure is formed. EFFECT: stabilized properties of seed material on storage. 2 ex

Description

 The invention relates to the sugar industry, in particular to the production of seed material, and can be used for boiling sugar massecuite for filling crystals in a vacuum apparatus.

 A known method of producing seed material, providing for the formation of crystals in a supersaturated solution by applying shear forces at a speed gradient from 5000 to 107000 cm / s / cm for 0.001 - 1.0 s. (SU 618054, C 13 F 1/02, 07/30/78).

 The disadvantages of this method are the difficulty of controlling the process of nucleation of crystals as a result of the short duration of impacts, as well as ineffective regulation of crystal growth, carried out by maintaining the solution and its gradual depletion.

The closest technical solution to the proposed one is a method for producing seed material, which involves preparing a saturated sugar solution at elevated temperature, crystallizing it by cooling to a temperature of 40 - 30 ^o C with vigorous stirring with the formation of fine crystals and packing the resulting seed material in molds (SU 82299, C 13 F 1/00, 05/28/49).

The disadvantages of this method are to obtain a seed material with polydisperse crystals (with a high coefficient of heterogeneity) formed during crystallization with uncontrolled cooling of a supersaturated solution with a very high supersaturation; the continuous formation of secondary crystallization centers (“flours”) along with the growth of primary crystals, since after cooling the solution with a mass fraction of solids of 88% to a temperature of 40 ^o C, the crystallization process is carried out with an initial supersaturation ratio of about 3 units. The seed material cannot be stored long enough due to the completion of the crystallization process with a high excessive supersaturation of the intercrystal solution, as a result of which the material completely hardens and is difficult to use.

 The technical result of the invention is to obtain a seed material having a solid viscoplastic structure with monodisperse crystals and stable storage properties.

This result is achieved by the fact that in the proposed method for producing seed material, which involves preparing a saturated sugar solution, crystallizing the latter with the formation of finely dispersed crystals by cooling with stirring to a temperature of 40-30 ^° C and packing the resulting seed material, when preparing a sugar solution, its saturation state is reached at a temperature of 50 ^o C. Before crystallization, a surfactant is added to the solution and the process is carried out using vibration stirring, followed by precipitating centrifugation of the crystalline mass to separate the concentrated suspension of crystals from the intercrystal solution, and a surfactant is added to this suspension, followed by vibrational stirring for its uniform distribution in the mass. For filling the seed material using fluoroplastic cylindrical pencil cases and maintain it in them until a solid structure is formed.

 The method is as follows.

A sugar solution is prepared by dissolving granulated sugar with a purity of 99.75% at 60 ^o C while stirring so that its saturation is reached at 50 ^o C.

If a saturated solution is prepared at a temperature much higher than 50 ^o C, then this will subsequently lead to an excessive increase in the initial coefficient of supersaturation at 40 ^o C and spontaneous crystal growth, as well as secondary crystal formation (the appearance of "flour"). Saturated solutions prepared at lower temperatures of 50 ^° C, on the contrary, have at 40 ^° C a low supersaturation coefficient, insufficient for stable crystallization.

Cooling a sugar solution saturated at 50 ^° C. to 40 ^° C. creates in it a supersaturation coefficient α = 1.1, which is necessary to initiate sucrose crystallization.

The prepared solution is placed in a crystallizer, and crystallization is carried out by cooling at an adjustable cooling rate of up to 40 ^° C. with low-intensity vibration mixing. When this temperature is reached, the intensity of vibration mixing is increased to a predetermined value of 0.092 - 2.49 m ² / s ³ . Before crystallization begins, a surfactant is added to the solution, which is distributed in the solution by vibration mixing.

The use of nonionic surfactants having a melting point of 28-30 ^° C, for example, acetylated stearic acid monoglyceride of 100% acetylation degree (AMHS-100), is contemplated as surfactants. AMGS-50 (50% acetylation degree), AMHD (distilled acetylated monoglyceride), etc. can also be used.

The cooling of the solution in the crystallizer from 50 to 40 ^o C is carried out with low-intensity vibration mixing to equalize the temperature of the solution, intensifying heat transfer and eliminating the premature appearance of crystallization centers before the start of controlled cooling from a temperature of 40 ^o C. The low vibration mixing intensity is controlled by the absence of crystals in the supersaturated solution before exit at a predetermined temperature of 40 ^o C. The use of high intensity mixing of supersaturated solutions can lead to cr building up. As established, this value of the intensity of vibration mixing corresponds to 0,092 - 2,49 m ² / s ³ .

After reaching a cooling temperature of 30 ^° C, crystallization is stopped, the resulting suspension is discharged from the crystallizer and concentrated by separating the crystals from the intercrystal solution by precipitation centrifugation at a separation factor of 1100 - 1600. A surfactant is added to the obtained highly concentrated crystal suspension with a mass fraction of crystals of 90 - 95% and using vibro-mixing with an intensity of 0.092 m ² / s ³ evenly distribute it in the volume of the suspension of crystals. After this, the resulting seed material is packed into fluoroplastic cylindrical canisters having a longitudinal separation of the body and maintained until the appearance of the properties of a solid visco-plastic system in the natural temperature conditions of the production room. The use of fluoroplastic canisters having low adhesion allows free extraction of calibrated cylindrical blanks of the seed material.

 Example 1

A sugar solution is prepared by dissolving granulated sugar with a purity of 99.75% at 60 ^° C. while stirring so that cooling is reached at 50 ^° C. The solution is then placed in a crystallizer. For a more uniform cooling of the solution to 40 ^o C carry out vibration mixing of the solution with low intensity. Before crystallization, a surfactant is added to the sugar solution - acetylated stearic acid monoglyceride of 100% acetylation degree (AMHS-100) in an amount of 0.002 wt.%. Upon reaching the upper limit of a predetermined cooling temperature range of 40 ^o C, the intensity of vibration mixing is increased to 0,092 m ² / s ³ . Controlled cooling is carried out at a rate of 2 ^o C / h The formation of crystals in a sugar solution is initiated by the vibrational action of a mixing device. Due to the addition of a surfactant to the solution, a slow decrease in the degree of supersaturation of the sugar solution occurs, which allows you to control the crystal growth process. When the lower limit of the specified range of the cooling temperature of 30 ^o C is reached, crystallization is stopped. The size of the sucrose crystals is 20 - 25 microns. After that, the resulting suspension is discharged from the crystallizer and concentrated, separating the crystals from the intercrystal solution by precipitation centrifugation at a separation factor of 1100. Then, the obtained highly concentrated suspension with a mass fraction of crystals of 90% is mixed with AMGS-100 in an amount of 1 wt. % and using vibro-mixing with an intensity of 0,092 m ² / s ³ distribute the surfactant in the volume of the suspension of crystals to prevent agglomeration and impart plastic properties. The resulting seed material is packaged in fluoroplastic cylindrical cases having a longitudinal separation of the body and the resulting seed material is maintained until the appearance of the properties of a solid structure in the natural temperature conditions of the production room.

 Example 2

A saturated sugar solution is prepared in the same manner as in Example 1. Before the crystallization, the surfactant AMGS-100 is added to the sugar solution in an amount of 0.01 wt.%. Upon reaching a cooling temperature of 40 ^o C, the intensity of vibration mixing is increased to 2.49 m ² / s ³ . Controlled cooling is carried out at a rate of 2 ^o C / h The formation of crystals in a sugar solution is initiated by the vibrational action of a mixing device. Due to the addition of AMGS-100, they slow down the decrease in the degree of supersaturation in solution. Upon reaching 30 ^o C crystallization is stopped. The crystal size is 10-15 microns. As in example 1, the resulting suspension is discharged from the crystallizer, the crystals are separated from the intercrystal solution by precipitation centrifugation at a separation factor of 1600. AMHS-100 is added to the resulting highly concentrated suspension with a mass fraction of crystals of 95% in an amount of 95% by weight and by vibration mixing. with an intensity of 0.092 m ² / s ³ distribute the surfactant in the volume of the suspension of crystals. The packaging of the obtained seed material is carried out in the same way as in example 2.

 Using the proposed method for producing seed material in comparison with the known one provides obtaining seed material with the properties of a solid viscous-plastic system and with a monodisperse composition of crystals and allows you to save quality indicators and properties of the seed material for a long time in unregulated temperature conditions.

Claims (1)

A method of producing seed material, comprising preparing a saturated sugar solution, crystallizing the latter with the formation of fine crystals by cooling with stirring to a temperature of 40-30 ^° C and packaging the resulting seed material, characterized in that when preparing the sugar solution, its saturation state is reached at a temperature of 50 ^o C, in this case, before crystallization, a surfactant is added to the solution and the process is carried out using vibrational mixing e, followed by precipitating centrifugation of the crystalline mass to separate the concentrated suspension of crystals from the intercrystal solution, and a surfactant is added to this suspension followed by vibrational mixing to distribute it uniformly in the mass, and fluoroplastic cylindrical cans are used to pack the seed material and hold it in them until formation of a solid structure.