SU1156749A1 - Apparatus for dust removal from granular materials - Google Patents

Abstract

THE DEVICE FOR DRAINING GRAINY MATERIALS, comprising a case in the lower part of which there are inclined perforated shelves fixed from one end to the side walls of the case and in the upper part of the case solid tilt Ie shelves with upper and lower gaps between their ends and side walls chassis, a charging nipple installed in the lower part of the hull, a nipple for supplying air and unloading nipples, so that, in order to improve the quality of dedusting by reducing the hydraulic The device is equipped with triangular cross-section inserts mounted on the side walls of the body across their entire width below the lower gap of each solid flange, and the size of the top 1 gap is determined from the ratio 0.53 6;, / i 0.58, the bottom - from ( L & Ratio 0.08, where and 6i, respectively, the value of upper, and lower gaps, ab the width of the body.

Description

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CD The invention relates to devices for the dedusting of polydisperse materials in the air stream and can be used in the chemical industry. A weighing device containing a housing, in the lower part of which there are inclined shelves, branch pipes for supplying and discharging material and air, wedge-shaped gas distribution grids p. The disadvantage of this device is the low efficiency of depletion. The wedge-shaped lattice does not practically affect the transport capacity of large parts, which is dangerous for ash. In this case, it is possible that the lattice is clogged, which increases the hydraulic resistance and disrupts the process conditions. The closest to the invention to the technical essence and the achieved result is a device comprising a case, in the lower part of which inclined perforated shelves are mounted, fixed from one end to the side walls of the case, and in the upper part of the case solid inclined shelves with upper and lower gaps between their ends and side walls of the casing, the loading nozzle installed in the lower part of the case, the nozzle for supplying air and the discharge nozzles i2j. The disadvantages of the known device are the low quality of dust removal and high hydraulic resistance. In addition, a change in the size of one of the gaps relative to the other adjacent leads to a decrease in the efficiency of dust removal. The purpose of the invention is to improve the quality of de-dusting by reducing the hydraulic resistance. This goal is achieved by the fact that the pondering machine, comprising a housing, in the lower part of which are installed inclined perforated shelves, fixed from one end to the side walls of the housing in the upper part of the housing - solid inclined shelves with upper and lower gaps between their ends and the side the walls of the casing, the loading step of the chutes, mounted in the lower part of the casing, the nipple for supplying air and unloading nipples, are provided with inserts of a triangular cross section mounted on the side walls of the casing. Rene under the lower gap of each solid shelf, and the upper gap is determined from the ratio of 0.53 in the lower - from the ratio of 0.08 to 0.15. where i and 0, respectively, the value of the upper and lower gaps, and B - the width of the body. FIG. 1 shows the apparatus, a general view; in fig. 2-3 - dependence of the dedusting efficiency of the material on the size of the upper and lower gaps, respectively; in fig. 4-5to the same, from the installation of the insert rectangular section. The apparatus for securing granular materials consists of a body 1 of rectangular cross-section, in the lower part of which there are perforated shelves 2 fixed by an upper end to the side walls of the body. Solid inclined shelves 3 with two gaps — upper 4 and lower 5 — are installed in the upper part of the body. A box 6 of rectangular shape is installed under the lower gaps. For feeding the source material, there is a loading nozzle 7, and for supplying air 1 a nozzle 8 with a gate 9. The finished products are unloaded through the nozzles 10 and 11. The apparatus works as follows. The source material through the nozzle 7 enters the space between the shelf 2 and the apparatus wall, where as a result of its interaction with the upward air flow coming through the nozzle 8 with a predetermined flow rate, which is regulated by pin 9, the trajectory of the material jets is curved and the jet hits the shelf where it slows down is loosened and scattered around the shelf. Small particles and some large ones are picked up by the air flow and carried to the upper separation part of the apparatus (above shelf 2). Here the stream meets shelf 3 and flows smoothly around it on the lower surface (the inlet 6) closes the entrance to the lower gap 5. With the accelerated movement of particles along the lower surface of the shelf 3, they are affected by inertial forces that depend on

3

the masses of the latter. Having reached the end of the shelf, the stream of particles crosses the upper gap 4 in the transverse direction. As a result of interaction with an exaggerated air flow, particle separation occurs. Large particles change the path of their movement less and more quickly than small particles reach the walls of the apparatus, where they lose their speed and fall down. The small particles and a part of the large ones are picked up by the air flow in the upper gap 4 and move to the next shelf 2. As a result of the flow turning, the particles are subject to centrifugal forces depending on their mass. This fact and the fact that the air velocity in the inter-shelf space is approximately equal to the velocity in the free cross section of the apparatus leads to the precipitation of particles (mostly large) onto the upper surface of the lower shelf 2. A layer of particles forms on the shelf, which moves to the lower gap and overloads . Since the air velocity in the lower gap 5 is approximately equal to its value in the upper 4, this ensures the effective release of small particles from the overloaded dense phase. The triangular insert 6 pulls the material away from the wall, eliminating the near-wall effect, reducing the quality of depletion. The separation process on the subsequent shelves 2 proceeds in a similar way. The selected pie leaves the apparatus through the nozzle 11, and the large particles through the nozzle 10.

In order to determine the optimal values characterizing the design parameters of contact elements (shelves) in the upper separation part of the apparatus, research was carried out in a laboratory setup on a series of materials with densities, quartz sand 2600, corundum 3500, ferrochrome 7800 powder.

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in the apparatus with two shelves (fed perforated and solid. in the upper part of the apparatus) from experience to experience change the size of the upper gap 1 last, which is expressed in relative units 1 / B, from 1 (there is no upper shelf) to O, i.e. . 1 0. At the same time, the passage of the material is possible only through the lower gap, the size of which in all experiments remains constant Ij / B 0.1 and provides 567494

It controls overload without blockage of the material that has fallen on the shelf. The inclination angle of the solid shelf to the horizon is 40 °. As follows from FIG. 2 5 (experimental material corundum), with a decrease in IY / V, the concentration of large Y and small (dust) Od, particles in ablation decreases. With a decrease from 1 to 0.55, the CC decreases by 6.7 times, 10 a Beats only by 1.9 times. Wherein

extraction efficiency E practically does not change, but at the same time the relative content of fine particles in the oi entrainment increases from 70% (1 / В 1) tS to 92% (1 / В 1) to 92% (1 / В 0.55), t . The quality of dusting is drastically increased. At, 53 and 1 / B / 0.58, the concentration of large particles of U in ablation increases dramatically, 20 decreases the value of V. As follows from FIG. 2, the maximum efficiency of depletion falls on a change interval of 0.58 0.53.

In the second group of experiments, the value of the upper gap 25 is constant (0.55), and the value of the lower Ij / B varies from 0 (there is no lower gap, the material accumulates on the shelf, not overloaded) to Ij / B 1 30 (upper shelf not). The bottom gap plays a dual role: it provides overloading of the material that has entered the shelf and its additional blowing (cleaning). The dependence of the concentration of large particles in the fly ash on the ratio Ij / B is complex (Fig. 3). The most optimal shelf mode at 0.15

IJ / B 0.08. At the same time, the MC with a change from 1 to 0.11 decreases approximately by 3 times, at the same time providing material overload from the shelf without its collapse at an optimum specific productivity for devices of this type of 10 s. At l2 / B 0.08 and at 12 / V 0.15, the concentration of large particles in the ablation increases dramatically, the effectiveness of dust removal decreases.

0 As follows from FIG. 2, the installation of a solid shelf in the upper separation part of the apparatus at 1 / B 0.55 and Ij / B 0.1, i.e. these values fall within the optimal ranges of the ratio and Ij / B, leading to a more significant decrease in the concentration of large particles Y, in ablation, as compared to small ones. Po511

the concentration of fine particles Uff in entrainment, and, consequently, the efficiency of dedusting, can be increased by increasing the resistance to the passage of air in the lower gap. As a result of this, a redistribution of its part to the upper gap occurs, and consequently, an increase in the speed of the air flow in this place. The latter is carried out by installing under the lower gap, across the entire width of the channel of the insertion of a triangular cross section, whose height is approximately equal to the length of the lower gap. KftK follows from figure 4 (quartz sand experimental material), the installation of the insert (scheme 2) compared with the device without the insert (scheme 1) leads to an increase in the concentration of small particles Y / vi in the bleed (at the optimal value of 1 ;, / В, which, as for Fig. 1 (corundum material) is 0.53 0.58) 1.3 times. The latter leads to an increase in the efficiency of dedusting E; by 8%, while the concentration of large particles in the fly ash remains almost unchanged. The latter is significantly the relative content of fine particles in the ash

67496

Using the AE-1 hot-wire anemometer, the velocity distribution of a single-phase flow and the effect on this insert and the size of the upper gap are examined, 5 At the same time, the Ij / V 0.1 value. In an apparatus without an insert (Scheme 2), the single-phase flow velocity in the lower gap. Vjj exceeds its value in the upper V by 1.7 times (Fig. 5).

О In an apparatus with an insert (scheme 1), the single-phase flow velocity in both gaps is approximately the same, i.e. air velocity in the lower gap, and hence the air flow

5 through it; diminishes to 1.7. times. At the same time, the air flow rate through the upper gap increases by 1.08 times, which leads to an increase in the removal of small particles, increasing them by 1.3 times.

20 concentration in the ash (Fig. 4).

Since the air velocity in both gaps is about the same, this ensures the same and high dedusting efficiency in both

25 gaps.

The use of the proposed apparatus will improve the quality of the dusty van materials.

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Claims (1)

APPARATUS FOR SPRAYING OF GRAIN MATERIALS, comprising a casing, in the lower part of which there are inclined perforated shelves fixed at one end to the side walls of the casing, and in the upper part of the casing - solid inclined shelves with upper and lower gaps between their ends and side walls of the casing, a loading nozzle installed in the lower part of the housing, a nozzle for air supply and discharge nozzles, which can be used in order to improve the quality of dust removal by reducing the hydraulic resistance claimed, the device is provided with inserts of triangular cross section mounted on the side walls over their whole width of the housing under the bottom gap each solid shelf, and the value 1 of the upper gap is determined from the ratio 0.53 / A 0.58, the lower one is ¹ from the ratio 0.08 ^ -jp / 0.15, where A and 6d are the magnitude of the upper and lower gaps, and the width of the body. 1 1156749. 2