RU2241925C1 - Method for granulation of sugar powder in suspended vortex layer - Google Patents

Abstract

FIELD: drying and granulation of dust-like food materials, such as sugar power, dry cocoa, soluble coffee, casein, dry milk, dry cream etc.

SUBSTANCE: method involves feeding sugar powder to suspended layer together with descending and ascending flows or by means of mechanical dosing device, with suspended vortex toroidal layer being sprayed with wet steam at the side of axis of rotation of flows. Ratio of descending and ascending flow rates to total flow rate is, respectively, from 5% to 35% and from 30% to 50%. Method allows effective combined dust catching and granulation processes to be performed in suspended vortex layer in single apparatus and spherical sugar granules to be produced without deteriorating of their consumer properties.

EFFECT: increased efficiency in dust catching of sugar powder by means of equipment with oppositely directed vortex flows.

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Description

The invention relates to the drying and granulation of pulverulent materials and relates to a method for granulating pulverulent food materials, for example, such as icing sugar, cocoa, instant coffee, casein, milk powder and cream, and others.

A known method of granulation of pulverulent materials in counter swirling flows (CDW), providing for the creation of a downward dusted mineral fertilizer, such as urea, a swirling stream in a cylindrical cavity, around a vertical axis and swirling in the same direction of the upward flow of air - coolant. In the known method, it is possible to create a weighted, torus-twisted layer of pulverized material, which provides the formation of granulation centers, which in a thermolabile state, by rolling grow to spherical granules of the required diameter and drop out of the suspended layer into a storage hopper [1], [2].

The disadvantage of these known methods is that in order to achieve coagulation of individual dust particles in a suspended swirl layer, in an apparatus with counter swirl flows, they must be brought to a thermolabile state, i.e. to the melting of their surface layer, which is completely unacceptable for food products, because this may lead to a violation of consumer qualities of the food product.

The closest technical solution, selected as a prototype [3], is the scientific article “On the question of granulation of sugar dust in devices with counter swirling flows”.

The disadvantage of the proposed method is that it is carried out according to the same technology as for granulation of mineral fertilizers in the apparatus of the CDW, such as urea and ammonium nitrate, i.e. by heating sugar dust to its surface melting, which is unacceptable, since sugar will lose its consumer qualities.

The problem to which the invention is directed is to obtain spherical sugar granules from powdered sugar without affecting the consumer qualities of sugar, as well as to combine two separate technological processes, such as highly efficient dust collection of powdered sugar and its granulation in a suspended swirl layer, in one volume of the apparatus CDW.

This is achieved by the fact that the method of granulation of powdered sugar in a suspended swirl layer, including the creation of a centrifugal field in the inner cylindrical cavity with a vertical axis of symmetry, provided with downward and upward swirling air flows, both flows swirling along the same direction, which, when combined, create the total output stream purified from the dust fraction, and between them create a weighted toroidal, swirling dust layer. In this case, the icing sugar is fed to the suspended layer together with the descending stream or together with the descending and ascending flows, or with a mechanical batcher in the initial zone of the already swirling downward flow, and on the side of the axis of rotation of these flows, the toroidal layer of icing sugar is irrigated with wet steam, while the cost ratio downward and upward flows with respect to the total flow rate of purified air are, respectively, 5 to 35% and 30 to 50%.

The invention is illustrated by the drawing, which shows a flow diagram of the movement of air flows, powdered sugar from a mechanical batcher and the precipitation of sugar granules from the layer, in the axial section of the apparatus with counter-flowing flows, limited by the internal cylindrical cavity of the apparatus.

The method of granulation of powdered sugar in a suspended swirl layer is as follows.

Into the inner cylindrical cavity of the apparatus 1 with counter-swirling flows with a vertical axis of symmetry 2, along which, in the ceiling area there is an outlet pipe 3 for air free of powdered sugar, a downward air flow 4 is introduced tangentially or twisted by an axial swirler, into which through downward 4 and 5 ascending flows, or powdered sugar is introduced by a separate mechanical or pneumatic flow 6. In the central part of the apparatus with the height, due to the ratio of downstream 4 and ascending 5 flow rates With respect to stream 7 in the outlet pipe 3, for example, 10 and 35%, respectively, a weighted swirling, toroidal layer 8 of powdered sugar 6 is created 6. At the same time, on the side of the axis of symmetry, moist steam 9 is sprayed onto layer 8, while moistened micro-dusts 10 of powdered sugar, coagulate each other by mutual rolling and quickly form spherical granules 11, which are kept near the lower boundary of layer 8 only due to the speed of movement from the swirling upward flow 5. As the diameter of granules 11 grows, their mass also grows. Moreover, as soon as the mass of an individual granule 11 exceeds a certain value, such a granule 11 falls out of the layer 8 and rolls into the storage hopper.

The inventive method will allow you to save tons of sugar, which in the form of micropowder passes through numerous separating cyclones, or cloth filters installed in all sugar factories in Russia, and is irretrievably lost in the environment, causing irreparable harm to it. In the inventive method, a vapor-flow stream directed to a dusty stream has the additional function of wet cleaning the air discharged into the atmosphere. Moreover, one such apparatus, installed in the technological chain of dust collection and purification of air discharged into the atmosphere, can replace several ineffective, but widely used Cyclone apparatuses in sugar production. The most economical and preferred technological scheme for using the proposed method will be that when dusty powdered sugar air enters the volume of the CDW apparatus simultaneously with the descending and ascending flows.

Sources of information

1. Candidate dissertation “Development of apparatus for the implementation of the process of granulation of pulverulent materials in counter swirling flows”, specialization 05.17.08. - processes and apparatuses of chemical technology. M., Moscow Textile Institute. A.N. Kosygina, 1982

2. USSR author's certificate No. 1164526 of 03/01/1985

3. Zemlyakov N.V. To the question of granulation of sugar dust in an apparatus with counter-swirling flows. - Orel: Oryol State Technical University. Collection of scientific works, volume 10, 1996, pp. 80-84.

Claims (1)

A method of granulating powdered sugar in a suspended swirl layer, including the creation of a centrifugal field in an inner cylindrical cavity with a vertical axis of symmetry, provided by downward and upward swirling air flows, both flows swirling along the same direction, which, when combined, create a common, free from dust fraction the output stream, and between them create a weighted toroidal swirling dust layer, characterized in that the powdered sugar is fed to the suspended layer together with the descending it with a stream or together with descending and ascending flows, or a mechanical batcher, and from the side of the axis of rotation of these flows, the toroidal layer of powdered sugar is irrigated with wet steam, while the ratios of the flow rates of the descending and ascending flows with respect to the total flow rate of purified air are 5-35%, respectively and 30-50%.