SU1216267A1 - Method of heat treatment of disintegrated wood material - Google Patents

Description

" one

The invention relates to methods for heat treatment of lumpy plate-like materials and can be used in pulp and paper industry in the heat treatment of process chips, bark and shredded wood.

The purpose of the invention is to increase the intensity of heat treatment of crushed wood material.

The drawing shows a device for implementing the method.

The device contains a loading device 1, an apparatus 2 for drying, a perforated bottom 3 of the apparatus, a transporting device 4 for transporting material during the drying process, an unloading device 5, an injection device 6 for supplying the coolant to the apparatus 2, a regulator 7 for the coolant flow rate damping capacity 8, the pulsator 9, the gas distribution box 10 of the apparatus 2.

Pulsed filtration of the coolant through a layer of wood material is carried out at a pulse frequency of 1-5 Hz, the borehole flow rate (the ratio of the pulse duration to the period between pulses) is 0.25-0.75 and the flow rate (the coolant at the moment of pulse action total section of the apparatus at the level of its perforated bottom (1.25-1.85 / i p, where O p is the critical filtration rate, determined by the formula

II / O. - -Frm-prl / -Rit / - /

where a is the acceleration of free

incidence equal to 9.80 m / s 5 h - thickness average) particles

material, m;

RM - density of the material, kg / m; WG heat carrier density,

kg / m

It was established experimentally that the effect of periodic separation of particles from each other with their return to the initial state of the bulk layer is achieved only if the specified parameters are specified simultaneously in the named limits.

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The constants I, 25 and 1.85 are obtained as a result of experimental testing of the proposed method and determine the range of the task

5 of the filtration rate of the heat carrier in fractions of the magnitude of the velocity and Crete which, in combination with the specified range of the frequency of interruption of the flow of the heat transfer medium, to it

10 porosity provides high-intensity heat treatment of the material.

When setting the ratio below 1.25, the separation of particles stops.

5 from each other, regardless of the implemented frequency and the pulse duty cycle. The material in the chamber remains in the bulk layer state. When setting a ratio higher than 1.85

20, the periodic return of the material to the initial state of the bulk layer is absent. There is a trend of ablation of material ie apparatus in the mode of pneumatic transport.

25 Based on the experiments, it was found that setting the flow ratio below 0.25 leads to a sharp drop in the intensity of the layer shaking. Particles of material do not separate 30 from each other. This effect is observed regardless of the realized pulse frequency and coolant flow rate.

An increase in the flow ratio above 0.75 causes the layer to become unstable. Periodic shaking of the material is eliminated. The return of the material to its original state of bulk

40 layers is missing. There is a tendency to carry away material in the mode of piston or pneumatic transport, regardless of the realized values of the frequency of the pulses and the speedy filtering of the coolant.

With a pulse frequency below 1 Hz, the intensity of the shaking of the material and the separation of particles from each other decreases sharply. The effect can be eliminated by an increase in the flow rate of the heat transfer medium, but this leads to the carry-over of material from the apparatus in the mode of piston or pneumatic transport.

55 With an increase in the pulse frequency of over 5 Hz, the intensity of the shaking of the material also decreases sharply. An increase in the consumption of heat ositel and the pulse porosity leads to the ablation of material from the apparatus in the mode of piston or pneumatic transfer motion.

The method is carried out in the following way.

The treatment material is continuously loaded into the apparatus 2 through the loading device 1, which is loosely poured onto the perforated bottom 3 to form a bulk layer up to 1.0 m. A pulsed flow of heat carrier is fed through the holes in the perforated bottom 3, the parameters of which are chosen within the specified range. The interruption frequency of the coolant flow in the range of 1-5 Hz and the flow ratio in the range of 0.25-0.75 provide the pulsator 9, the flow rate of the coolant filtration rate of the coolant at the time of arrival of the pulse in the range (1.25-1, 85) in the calculation of the total cross-section of the apparatus at the level of its perforated bottom 3, it is provided with a regulator 7 of the coolant flow rate.

The heat carrier flow pulses, thus formed, when filtering through the material in the apparatus, periodically shake the material, separating the particles from each other, and then returning them to the initial position of the bulk layer after the impulse stops. This is

0.25-0.750.80-1,200,540,5031-57

. 0,25-0,751,250,5-0,790,5077-98

0,25-0,751,550,75-0,790,5097-123

0,25-0,751,850,75-0,790,50109-W8

0.25-0.75, 2.00-3,000.87-0.930.50

0.171.25-1.850.51-0.540.5031-57

0.831.25-1.850.83-0.910.50

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The developed surface of the interaction of the material with the coolant and, accordingly, the intensity of heat treatment is high, and 5 also the stability and stability of the process.

In the process of heat treatment in the apparatus, the material is moved in the horizontal direction along the perforated bottom 3 in the direction of the unloading device 5 through a mechanical device 4 of the scraper conveyor type 10, through which the material is continuously

15 outputs from the device. The spent coolant is removed from the apparatus and fed into the gas cleaning system and further into the atmosphere.

The table shows the experimentally obtained data for; different modes of processing bark. In the experiments, a material of polydisperse composition with a particle gap of 1-30 mm was used.

25

As follows from the data in the table, high heat exchange intensity and stability of its implementation are achieved while setting

30 pulse frequencies in the range of I - 5 Hz; the duty ratio of the flow is 0.25-0.75. and the filtration rate of the coolant in the calculation of the total section of the apparatus at the level of its perforated bottom in the range U / U | c «UT 1.25-1.85. .

Caperns was driving

Particle separation FRIEND from a friend

Also -

The material is carried away by the apparatus of the porthole mode of dvdzhknn

Material be dva zhui

The material is carried away by the machine.

Claims (1)

METHOD FOR THERMAL PROCESSING OF MILLED WOOD MATERIAL by pulsing purging of a material layer with a gaseous heat carrier stream, characterized in that, in order to intensify the processing of the material, the purge is carried out at a pulse frequency of 1-5 Hz, a duty cycle of 0.25-0.75 and a heat carrier flow rate when it enters the material layer (1.25-1.85) 0 _K p _IT , where _{k? ig} is the critical purge rate, which is determined by the formula ^where is the density of the material being processed, kg / m *; Рт - heat carrier density, ‘kg / m * ·, h - material particle thickness, m; - acceleration of gravity, 9.8 m / s. SU. 1216267