RU2410614C2 - Method of processing granular materials and device to this end - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to processing of loose, primarily, inhomogeneous, materials to be used in chemical, food, microbiological and other industries. Proposed method comprises feeding material into rotary drive with lifting vanes, blowing the curtain of falling particles by gaseous agent or gas-fluid mix, controlling relationship between time of falling of particles in drum lifting and lowering sections by sending different-magnitude pulses to them in direction of discharge. Rotary drum with extension comprises system of lifting vanes secured on the drum inner surface and deflecting elements fixed in horizontal plane and arranged in parallel and symmetry about drum axis. Said deflecting elements are made up of funnels with inclined pouts. It comprises also rotary plate secured on adjacent edges of said funnels. Said pouts are secured on funnels to vary direction of their inclination via turn about vertical axis.

EFFECT: invention improves uniformity of processing and expands process performances.

Description

The invention relates to technology and equipment for the processing of bulk, mostly heterogeneous, materials by arranging their contact with a gaseous agent (vapor-gas or gas-liquid mixture) in the chemical, food, microbiological and other industries.

There is a method of processing bulk materials, which consists in feeding them into a rotating drum, adjusting the average processing time by changing the fill factor of the drum and unloading materials (see USSR author's certificate No. 1486720, class F26B 11/04, BI No. 22 of 15.06. 89). A device that implements this method contains a rotating inclined drum having a retaining ring in its discharge part, made with an adjustable damper in the form of a rotary sector, pivotally connected through a rod with a drive.

The disadvantage of these technical solutions is the heterogeneity of the processing of particles that vary in size and density, due to the different time spent in the working volume, due to the formation of segregated flows of material in a rotating drum. Controlling the average residence time of particles does not exclude the heterogeneity of their processing.

The closest in technical essence to the claimed method is a method of processing bulk materials (see USSR author's certificate No. 1326857, CL F26V 11/04, 25/16, BI No. 28 of 07/30/87), which consists in feeding material into a rotating drum with lifting blades, purging the curtain of falling particles with a gaseous agent, impulses to particles falling in the lifting and lowering parts of the drum, for the purpose of their longitudinal movement and unloading of the material. A device that implements this method is a nozzle of a rotating drum containing a system of lifting blades mounted on the inner surface of the drum and deflecting elements fixed in the form of funnels with oblique chutes and fixed on adjacent the edges of the funnels of parallel rows of a rotary plate.

The disadvantage of such solutions is the heterogeneity of the processing of materials consisting of particles that are heterogeneous in size and (or) density, due to the difference in their heat and mass transfer properties and different uncontrolled residence times of such particles in the working volume.

The objectives of the proposed method and nozzles are to increase the uniformity of processing bulk materials consisting of particles of various sizes and densities, and expand their technological capabilities.

The solution of the technical problem is achieved by the fact that:

1. In the method of processing heterogeneous bulk materials, which consists in feeding material into a rotating drum with lifting blades, blowing a curtain of falling particles with a gaseous agent or gas-liquid mixture, and sending pulses to particles falling in the lifting and lowering parts of the drum, and unloading the material, according to the invention, the ratio is controlled processing time of particles falling in the lifting and lowering parts of the drum by communicating them with different pulses in the discharge direction.

2. In a device for processing inhomogeneous bulk materials, mainly a heat and mass transfer device, consisting of a rotating drum and a nozzle of a rotating drum, containing a system of lifting blades mounted on the inner surface of the drum, and deflecting elements that are fixedly mounted in a horizontal plane in parallel rows symmetrically relative to its axis, made in the form of funnels with inclined chutes, and a rotary plate fixed to adjacent edges of the funnels of parallel rows, with publicly invention estrus fixed to the funnels with the possibility of changing direction of inclination, for example by pivoting them about a vertical axis in order to control the ratio of processing time of inhomogeneous particles falling into the lifting and descending parts of the drum.

The essence of the proposed method is as follows.

When bulk material is fed together with a gaseous agent into a rotating drum with lifting blades, a material backfill is formed in its lower part, the segment height of which is greater than the height of the blades, which is necessary for the nozzle to function normally. In the filling of material above the blades of the lower part of the drum, a segregated shear gravitational flow of particles is formed. Moreover, near the open surface of the backfill, the segregated stream is enriched in large and less dense particles, while small and denser particles are concentrated near the base of the stream. As a result, the blade is initially filled with larger and less dense particles from the open surface of the segregated stream and then with smaller and denser particles from its deep layers. As a result, small and denser particles are poured from the blades in the lifting part of the drum, and then larger and less dense particles fall in the lower part of the drum.

Since the size and density of particles falling in the lifting and lowering parts of the drum are different, as well as the hydrodynamic conditions of their movement in the drum, the required ratio of their residence time in the rotating drum is established to ensure their processing uniformity. This is achieved by communicating to the inhomogeneous particles falling in the lifting and lowering parts of the drum different pulses in the discharge direction.

Figure 1 presents a diagram of a heat and mass transfer device for implementing the proposed method for processing heterogeneous bulk materials, figure 2 is a section aa in figure 1, and figure 3 is a section bB in figure 1.

The heat and mass transfer device comprises a rotating drum 1 with a peripheral L-shaped nozzle 2, a loading chamber 3 with nozzles 4 and 5 for introducing material and a gaseous agent, an unloading chamber 6 with nozzles for conveying material 7 and spent agent 8. In the drum, its axes are fixedly mounted symmetrically two rows of deflecting elements made in the form of funnels 9 with oblique chutes 10 mounted on funnels with the possibility of rotation about a vertical axis. In order to autonomously control the magnitude of the longitudinal impulse acting on the falling particles in the lifting and lowering parts of the drum, the heat of each row is pivotally connected by a common rod 11 with a drive additionally installed outside the drum. A rotary plate is fixed on the mating edges of the funnels of the parallel rows.

The magnitude of the longitudinal impulse is controlled by changing the angle α formed by the estrus axis and the axis of the drum in projection onto a horizontal plane (Fig. 3). The magnitude of the pulse is proportional to cos (α), and the smaller the angle a, the shorter the average residence time of the corresponding particles in the apparatus. The necessary ratio of the residence time of particles falling in the lifting and lowering parts of the drum is established by adjusting the ratio of the values of the corresponding pulses.

In the absence of distinguishing features of the proposed method and device, particles of material that are heterogeneous in size and density move in the working volume in segregated flows and have different residence times in the drum. As a result of this, as well as due to various heat and mass transfer properties of the particles, heterogeneity of their processing occurs.

It is advisable to install deflecting elements in the immediate vicinity of the blades, since these areas are characterized by the highest density of the flow of falling particles (see Kartoshkin A.D., Shapovalova O.G., Kipriyanov Yu.I. Obtaining mineral fertilizers in drums of granulator-dryers. Chem. prom., 1979, No. 1, pp. 40-43). The width of the elements can be equal in the limit to the radius of the drum minus the height of the lifting blades.

The angle of inclination of the leaks of the deflecting elements to the horizon should obviously be greater than the angle of friction of the material on the surface of the elements. The choice of the length of the deflecting elements should be carried out for the following reasons.

EXAMPLE. In a drum dryer of granular mineral fertilizers with a drum with a diameter of 0.3 m and a length of 1.25 m, having L-shaped blades 0.03 m high along the entire length and installed motionlessly in the axial zone horizontally, symmetrically to its axis, 2 rows of deflecting elements, made in the form of funnels with estrus, inclined at an angle of 40 ° to the horizontal, superphosphate granules with a particle size distribution of + 1.0-4.0 mm are fed in countercurrent with a drying agent. In each row, 8 deflecting elements were installed - funnels having a receiving neck with a size of 0.115 × 0.15 m. A rotary plate 1.2 m long and 0.115 m wide was fixed on the mating sides of the funnels of parallel rows.

The leaks are fixed on the funnels with the possibility of rotation relative to the vertical axis of the funnels. In each row, all estrus are pivotally connected to a common rigid longitudinal thrust, which is brought out of the drum and connected to an autonomous drive. The drive provides the possibility of longitudinal movement of the thrust, which is accompanied by the rotation of the leaks relative to the axis of the funnels.

In order to increase the uniformity of moisture content in the dried material, different residence times of large and small granules in the apparatus are established. For this, the heat of the funnels located in the lifting part of the drum is set at an angle of 0 °, and the heat of the funnels in the lower part of the drum is set at an angle of 75 ° to the axis of the drum in a horizontal projection in the discharge direction.

As a result, the average residence time of a large fraction of granules (+ 2.5-4.0 mm) is 1.7 times the average residence time of the material in the apparatus.

The proposed method and device allows you to use the effect of separation of particles by size and density, observed in a curtain of falling particles in a rotating drum with lifting blades, for the rational organization of the processing of bulk materials prone to segregation by controlling the ratio of the processing time of inhomogeneous particles in the working volume of the apparatus. Compared with the prototype, the proposed technical solutions provide a higher uniformity of material processing, expand the functionality of the equipment and increase the technical and economic indicators of its functioning.

Claims (2)

1. The method of processing heterogeneous bulk materials, which consists in feeding the material into a rotating drum with lifting blades, purging the curtain of falling particles with a gaseous agent or gas-liquid mixture, sending impulses to particles falling in the lifting and lowering parts of the drum, and unloading the material, characterized in that it is controlled the ratio of the processing time of particles falling in the lifting and lowering parts of the drum, by communicating them different pulses in the direction of discharge. 2. The nozzle of a rotating drum, mainly a heat and mass transfer device, for implementing the method according to claim 1, comprising a system of lifting blades mounted on the inner surface of the drum and deflecting elements fixed in the horizontal plane in parallel rows symmetrically relative to its axis, made in the form of funnels with inclined estrus, and a rotary plate fixed on adjacent edges of the funnels of parallel rows, characterized in that the estrus is fixed on the funnels with the possibility of change the direction of their inclination, for example, by rotating them relative to the vertical axis in order to control the ratio of the processing time of inhomogeneous particles falling in the lifting and lowering parts of the drum.

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