RU2269731C2 - Powder material drying plant - Google Patents

Abstract

FIELD: drying equipment, particularly for agriculture, food and other industries.

SUBSTANCE: drying plant for drying powder material, preferably grain, comprises loading hopper, drying part including chamber with fluidized powder material layer, cooling part, electric heater and centrifugal pump. The chamber has conical body provided with inclined perforated grids arranged in the body. Grain layer thickness stabilizers are arranged inside the chamber over perforated grids. The grain layer thickness stabilizers are made as vertical plates sliding along vertical axis. Cooling chamber comprises grain drying and cooling governors made as frequency-controlled rotary dischargers.

EFFECT: increased efficiency.

1 cl, 2 dwg

Description

The invention relates to techniques for drying bulk materials and can be used in agriculture, food and other industries.

The well-known "Installation for bulk materials" (patent No. 2041434, priority from 08.30.95), which includes a fluidized bed dryer in the form of a cylindrical body with alternating central funnels located in the form of a belt, made in the form of a straight peripheral cone oriented upward and installed axisymmetrically in a cylindrical housing, and peripheral funnels in the form of a truncated cone, oriented to large bases upward, adjacent to the walls of the housing, with overflows in the form of an annular mana formed by the cylinder and the body in the periphery of the central funnels and in the form of transfer pipes in the centers of the peripheral funnels, the angle of inclination of the forming central funnels is 1.2-1.5 times, and in the peripheral 2-4 times the angle of repose of the bulk material, the perforations of the funnels for the passage of the drying agent are made in the form of arched slots with a convexity upwards, arranged in concentric circles with respect to the axes of the funnels, the direction of the axes of the arched slots is tangential at the central funnels and at an acute angle to the image from the perforation to the center, and to the same side on the peripheral funnels, a pipe in the lower part of the housing for the wire of the drying agent and a tangentially attached pipe in the upper part of the housing, coinciding with the direction of the axes of the arched slots, the central pipe up to enter the dried bulk material and a central nozzle at the bottom for discharging dried bulk material, a cyclone connected to an outlet nozzle of the housing, a suction fan connected to an exhaust nozzle of the cyclone; the unit is equipped with an additional large-diameter fluidized bed dryer and the same design with similar central and peripheral perforated funnels and transfer devices, nozzles for introducing and discharging the drying agent and bulk material, elevators for feeding the dried material to the upper part of the shaft dryer, the dried material with the bottom of the shaft dryer, a fan for the dryer, the installation is also equipped with a cooler with a fluidized bed of dried material, made similarly as and the first dryer.

The closest analogue in design to the inventive installation for drying bulk materials is the following device.

Known multi-chamber cylindrical dryer with inclined grates (company Lurgi, Germany) ("Food Industry" Moscow. 1966, p.104). This installation consists of a drying chamber, a cyclone, grates, a hopper, a heater, a fan and a zone for unloading dry material, the drying and cooling zones being directly interconnected and the air passing through the cooler after dusting and additional heating is sent to the drying zone. This installation is characterized by high efficiency and cost-effectiveness of bulk materials with high initial humidity, and due to the use of the heat of chilled grain, the thermal efficiency of the apparatus increases significantly, but it is very metal-consuming, cumbersome and not suitable for use in small farms, besides, grain located on the inclined surfaces of the funnels are distributed unevenly, the thickness of its layer cannot be regulated, which leads to uneven drying of the grain.

The closest analogue to the claimed device is a heat exchanger A.S. No. 289274, cl. F 26 B 17/12 is a prototype in which baffles are installed over the inclined gas distribution grid to level the layer of the material to be dried with mixing, made in the form of concentrically arranged shells with bases placed at the level of the bases of the respective shelves forming the gas distribution grid.

This heat exchanger has the following disadvantages: it is difficult to carry out controlled release of grain when it leaves the gas distribution grid, an increase in the productivity of the device will lead to an excessive increase in the diameter of the base of the cone, and an increase in the unevenness of the grain flow, i.e. determine different aerodynamic drag of the grain layer and lead to uneven cooling. In addition, intense heat transfer in the fluidized bed of grain, especially in the upper part of the device, will slow down the evaporation of moisture from the grain when it is cooled and may cause, due to a sharp change in temperature, the formation of cracks and a decrease in cereal yield for cereal crops.

The aim of the invention is to increase productivity and efficiency when cooling bulk material by air, reducing the metal consumption of the device, the possibility of using dryers in small farms.

This goal is achieved in that the design of the installation for drying bulk materials consists of a loading hopper, a drying and cooling zone, an electric air heater, a centrifugal fan, while the drying zone consists of a chamber with a fluidized bed of granular material in the form, for example, of a conical body with located perforated inclined gratings, stabilizers of the thickness of the grain layer, made in the form of vertically placed plates and mounted with the possibility of moving them vertically axis, and the cooling chamber contains a controller for drying and cooling the grain, made in the form of a lock gate with an adjustable speed.

The installation for drying bulk materials is shown in the drawings.

Figure 1 - General view of the installation.

Figure 2 is a view along arrow A.

The installation for drying bulk materials consists of a feed hopper of raw grain 1, a drying chamber 2 and a cooling zone (chamber) 3, an electric air heater 6, a centrifugal fan 7, an unloading device 8. The drying chamber 2 consists of a conical body 4, an inclined perforated grate 5, stabilizers the thickness of the grain layer 6. The cooling zone (chamber) 3 consists, see FIG. 2, of two inlet boxes 10, the end sides of which are open (indicated by a + sign in FIG. 2) and three outlet boxes 11, one of whose end sides is closed yta (in Figure 2 indicated by the sign -), and the other - is open (not shown), a suction fan nozzle 9 July.

Installation for drying bulk materials works as follows.

Raw grain is loaded into the hopper 1 and sent to the perforated grate 5 of the drying chamber 2, on which the grain layer of a given thickness is placed. The thickness of the grain layer is formed due to the installation of stabilizers 6, which are vertically arranged plates mounted with the possibility of their movement along the vertical axis, which allows you to adjust the gap between them and the perforated grate 5. The grain layer on the grate 5 is fluidized by a drying agent supplied through a centrifugal electroheater 6 a fan 7, the suction pipe 9 of which is connected to the cooling chamber 3. Due to the fact that the perforated grate 5 is inclined and the grain layer penetrates drying agent and flows through the perforated grate 3 from top to bottom into the cooling chamber 3. The cooling chamber 3 consists of two inlet boxes 10, the end sides of which are closed, and three outlet boxes 11, one of the end sides of which is closed and the other is open to the suction pipe 9 centrifugal fan 7. When the cooling chamber 3 is full, the grain is intensively cooled by blowing air through it. Atmospheric air through the inlet ducts 10 blows a dense layer of grain and through the outflow ducts 11 by the fan 7 is directed to the drying chamber 2 after it is preheated - heating in the air heater 6. This saves energy costs for heating and cooling the grain. For more intensive cooling of the grain layer, the walls of the boxes 10 and 11 are made louvered.

The length of time the grain stays on the grate 5 is regulated by the unloading device 8 of the cooling chamber 3, which, in fact, performs the function of a grain drying and cooling regulator made in the form of a lock gate with an adjustable rotation speed. When the drying control is completely stopped, the grain layer “boils” on the grate 5 and does not move. When the drying control rotates, the grain layer moves along the grate. Thus, the duration of drying and cooling the grain is controlled by the speed of the drying controller.

A feature of the inventive installation for drying bulk materials is that to fluidize the grain on an inclined grate, a slight pressure of the drying agent under the grate is necessary, and to prevent the grain from draining along the inclined surface of the grate, the device is equipped with stabilizers for the thickness of the grain layer. The presence in the device of the cooling chamber contributes to the cooling and more intensive removal of moisture of the grain.

Claims (1)

Installation for drying bulk materials, mainly grain, including a loading hopper, a cooling zone, a drying zone, consisting of a chamber with a fluidized bed of granular material in the form of, for example, a conical body with perforated inclined gratings and stabilizers of the thickness of the grain layer located in it, characterized in that the stabilizers of the thickness of the grain layer are mounted with the possibility of movement along the vertical axis.

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