SU1753218A1 - Pneumatic gas drier for peat - Google Patents

Abstract

Using; drying technology of milling peat in pneumotubes in the manufacture of briquettes, which provides an intensification of the drying process and increase reliability by reducing the abrasive wear of pneumotubes. Summary of the Invention; the pneumotube above the loading unit is made. in the form of a Venturi tube with a multi-blade swirler placed in its confused part. In this case, the lower edges of the swirler are placed on the border of the Venturi tube, and the upper edges are cut at an angle to the horizontal plane. Moreover, the sides of the nodes converge at the point of intersection of the boundary line with the axis of the pneumatic tube, which is concentric with the top inlet pipe of the heat transfer medium with a living cross-section area of 10-15% of the pneumatic cutting live area. 2 or

Description

The invention relates to a technique for drying dispersed materials and can be used for drying milled peat in the manufacture of briquettes.

In pneumogas pipe-dryers, flue gases are at the same time heat carrier, transporting medium and drying agent. Peat particles, suspended in the flue gas flow, overcome the distance from the loading point to the cyclone in a short time, without having managed, as a rule, to reach standard humidity. In order to achieve the required moisture content of the material particles while maintaining the specified performance, -Dryers This leads to an increase in metal consumption, an increase in energy consumption.

Known pneumatic dryer for bulk materials, containing a vertical chamber with reinforced on its inner

wall reflectors arranged in an upward spiral with a variable pitch.

The pneumogas peat dryer is also known, which contains a vertical pneumatic pipe, lower and upper heat carrier inlets, a source material loading unit placed between them, radial rods mounted on the inner surface of the pneumatic pipe in a spiral and having a length equal to the width of the upper input.

Devices in the form of segmental reflectors, snails with pins perform the function of braking devices that reduce the velocity of particles, increase the residence time of particles in a stream of gases, additionally grind the largest particles and ensure, therefore, the achievement of equal and conditioned moisture of particles, i.e. . devices of this type contribute to the intensification of drying processes.

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However, during the turbulization of the flow created by these devices, particles of the material, being in a swirling flow, when rubbing against the surface of the pipe, create local zones of gas-abrasive wear in the pipe, in cochleas with pins. In dryers with segment reflectors, wear is localized at the corners of the interface between the reflector and the pipe surface. In these places, after 10–12 thousand hours of the dryer’s operation, at a pipe wall thickness of 10 mm, holes appear.

The known structure does not ensure uniform distribution of the material in the gas suspension flow across the cross section due to the formation of stagnant zones in the flow of cold areas behind the reflectors, which impairs heat transfer and reduces the intensity of drying,

In addition, the shredder turbulator in the form of radial rods acts only on the peripheral layer of the flow, and in the core of the turbulization it is small and the particles are not crushed. This reduces the drying intensity and the productivity of the dryer due to the inefficient use of its volume. On the pins, the peat fiber may hang, which reduces the reliability of the dryer. When the coolant is supplied externally to the pin area, there is a significant heat loss to the environment.

The purpose of the invention is to increase reliability by reducing the abrasive wear of the pneumatic tubing,

This goal is achieved by the fact that in a pneumogas drier for peat containing a vertical pneumatic tube with upper and upper coolant inlets and a material loading unit placed between them, the pneumatic tube above the loading unit is made in the form of a Venturi pipe with a multi-blade swirler placed in its confusing part. In this case, the lower edges of the swirler are placed on the border of the Venturi tube, and the upper edges are cut off at an angle to the horizontal plane, and the sides of the corners converge at a point lying on the border with the axis of the pneumatic tube, The main pipe of which is installed is the top inlet pipe of the heat transfer medium with the area of the living section constituting 10-15% of the area of the living section of the pneumatic tube.

FIG. 1 shows a diagram of the dryer: in FIG. 2 - View A in FIG. one.

The pneumogas dryer for peat consists of a vertical pneumatic tube 1 with a lower inlet 2 of the heat-transfer gas and a unit 3 for loading the source material (Fig. 1). A replaceable device, made in the form of a Venturi tube 4, is installed above the loading unit. In the confused part of the Venturi tube there is a multi-swirl swirler 5 (Figs. 1 and 2). The blades 6 are angled to the flow of the gas suspension and secured with one

5 sides on the confuser surface, on the other hand are connected to the axial nozzle 7, the lower edges of the inclined blades of the swirler are placed on the border of the Venturi tube, and the upper edges are cut at an angle to

0 of the horizontal plane, with the sides of the corners converging at a point lying on the border with the axis of the pneumatic tube, with a pneumatic tube concentrator, the upper inlet 8 of the heat carrier is installed. The area of the living section of the upper input f- - 0.10-0.15 F, where F is the area of the living section of the pneumatic tube. The outlet of the dryer is connected via a cyclone to a fan (not shown).

The dryer works as follows.

0 The heat-transfer gas entering the dryer is spontaneously distributed into two streams; The main flow of the suspension is directed into the space bounded by confuser surfaces,

5 nozzle 7 and blades; swirl; the rest of the flow (10-15%) is in the upper inlet 8. The source material enters the pneumatic tube 1 through the loading unit 3 and is picked up by the heat-transfer gas fed through the lower inlet 2. When the flow of the gas suspension passes through the fuser 5 under the influence of inclined blades 6 there is a more uniform distribution of peat particles over the area

5 cross-section pneumatic tubes, additional grinding of the largest particles on the blades, their braking and spinning over the entire cross-sectional area. Turbulization on the blades of a swirler of a material that is evenly distributed over the cross section of the pneumatic tubing and entering a fresh portion of the coolant along the shortest path, i.e. along the axis of the pyothotrub with a concentrically set

5 nozzle top entry, intensified drying.

With a uniform distribution of the gas suspension flow over the swirl section, the wear is concentrated mainly on

0 popast and to a lesser extent on the walls of the pipe. This eliminates the zone of local gas-abrasive wear, as observed in dryers with segmental reflectors.

5 The arrangement of a multi-blade swirl in the confused part of the Venturi tube allows, due to the conical surface, to somewhat compress the flow of the gas suspension and direct it to the blades of the swirler. Some

almost no increase in flow rate

influences the wear pattern of the swirler and the adjacent pipe surfaces and helps to ensure that the fibrous parts of the end face pass along the surface of the blades without smearing them. This increases the reliability of the dryer.

By placing the lower edges of the swirler on the border of the Venturi tube, a more accurate assembly of the swirl structure is achieved, and the fact that the upper edges of the blades are cut at an angle to the horizontal plane and the sides of the angles converge at the point lying on the boundary of the pneumatic tube, the surface of the blades and their best twist. For larger and heavier particles, a longer runway path is required. Particles of smaller mass, including the fibrous parts of peat, have a slightly higher speed, are distributed closer to the flow axis and accelerate faster in shorter parts of the blade.

The ratio of the area of the living section of the upper entry and the area of the living section of the pneumatic tube is calculated by calculation and according to simulation data equal to 10-15% based on ensuring that 10-15-15% of the fresh heat carrier is supplied to the zone of the Venturi pipe for drying peat.

The results of the investigation of the wear processes of pneumogas dryers show that due to a more even distribution of the flow of gas suspension across the cross section of the pneumatic tubes in the proposed dryer, the temperature field is equalized in the cross section of the casing behind the Venturi tube and the decrease in the intensity of the gas abrasive wear of the dryer casing. Destruction of welds and warping of the hull are excluded. Depreciation is localized mainly on

the blades of the vortex of the Venturi tube, which, after working off a given resource, is subjected to restoration or replaced by a new one.

Intensification of drying in the proposed

a pneumogas drier for peat allows you to increase the productivity of the dryer, reduce the outlet temperature, reduce the moisture content of the dried product, or reduce the length of the pneumatic tube.

Claims (1)

Invention Formula Pneumogas peat dryer containing a vertical pneumatic tubing with the lower and upper coolant inlet pipes and a material loading unit placed between them, so that, in order to increase reliability by reducing abrasive wear pneumatic tubes, last above the loading unit, are made in the form of a Venturi tube, with the lower edges of the swirler placed at the entrance to the Venturi tube, and the upper edges are angled to the horizontal plane, the sides of the angles converging at the point lying at the intersection of the plane of the Venturi pipe entrance junction and vertical section of pneumatic tubing with pneumatic tubing axis, which is concentrically mounted the upper inlet pipe of the heat carrier with a living cross-section area of 10-15% of the air-cutting live cross-section area.  four 7