SU1048276A1 - Method of automatic control of process of drying loose material - Google Patents

Description

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The invention relates to automating the process of drying bulk materials and can be used in the chemical industry, for example, in drying calcium borate in rotating drums.

There is a method of automatically controlling the drying process of bulk materials in a drum dryer by affecting the speed of rotation of the drum according to the moisture content of the material at the drum outlet and the rate of change of the temperature inside the drum tl 3

The disadvantage of this method is the high specific fuel consumption for drying due to the lack of control and regulation of the vacuum in the mixing chamber.

There is also known a method of automatically controlling the drying process of bulk material, implemented by an automatic control of the drying mode, by measuring the moisture content of the dried material, changing the position of the exhaust fan damper on the humidity of the dried material, stabilizing the temperature in the mixing chamber by changing the C2 fuel supply.

A disadvantage of the known method is the lack of an estimate of the speed of movement of the material along the drying drum, which leads to specific fuel consumption.

The purpose of the invention is to increase the languor in regulating the drying process.

The goal is achieved by the method of automatically controlling the drying process of the bulk material by stabilizing the temperature in the mixing chamber by changing the fuel supply and changing the smoke exhauster damper on the humidity of the dried material after the drying drum to measure the vacuum in the mixing chamber and the speed of the material moving through the drying drum and the position of the smoke exhauster damper additionally changed according to measured parameters.

The essence of the method lies in the fact that the speed of movement on the dryer drum depends on many parameters: initial moisture, flow rate, particle size distribution of the material, etc. Consequently, the rate of movement of the material through the tumble dryer can be used in

as a complex paoametra characterizing the total perturbation of the drying process.

Figure 1 presents the block diagram 5 of the device that implements the proposed method; Fig. 2 shows an example of graphs of changes in the values of the heights of material lifting in the first (n (t) and second (Hnit) cross-sections of xx. drying

O drum by time t; FIG. 3 is an example of a graph of the variation of the interrelations. relational function (R (C).

The device, the implementation of this method, contains a dryer drum 1,

5 loading chute 2, mixing chamber 3, exhaust fan k, gate 5 of the exhaust fan, temperature sensor 6 in the mixing chamber, temperature controller 7, actuator 8, vacuum regulator 9, humidity sensor

10 dried material, sensor times; 11 in the mixing chamber, sensors for lifting material 12 and 13, memory blocks I and 15, a correlator 16, a unit for determining time of movement of material 17, a unit for determining the speed of movement of material 18.

The method is carried out in the following manner.

0 The wet material through the chute 2 enters the rotating drum 1, where, in the flue gas flow, it moves to the discharge end of the drum 1. The exhaust gases from the drying process suck the exhaust fan.

A system for automatic control of the drying process with an ostoit of two independent control loops.

0 Circuit I control is intended to stabilize the temperature in the mixing chamber by changing the fuel supply (for example, gas, fuel oil).

Regulator 7 changes em

The position of the actuator 8, standing on the fuel supply pipe, according to the temperature in the mixing chamber 3, measured by the sensor 6. While controlling the fuel consumption, the amount of air is not changed, since the fuel in the furnaces of the drying drums is burned with large excess air.

Control circuit II is designed to control the vacuum in the mixing chamber.

The regulator 9 changes the position of the damper gate 5 k according to the magnitude of the vacuum measured by the sensor 11. The vacuum in the mixing chamber is adjusted according to the moisture content of the dried material measured by the sensor 10, as well as by the speed of the material moving through the drying drum obtained after the block 18.

For determining the speed of movement of the material, V values of the lifting heights of the material in the first (second (N2 / drum cross sections 1, measured by sensors 12 and 13 (for example, radioactive J, are remembered in blocks 14 and 15, and the change in H value and H2 is random) The correlator 16 determines the mutual correlation function R (C) of the parameters Hg according to the values of H and Well, which it chooses from the N and IS blocks. The calculation is based on the following dependence: t

Y {t} H (t-r) dt;

R (f)

i 2

, ..., ..........

T - variable temporary intergde shaft;

T is the time of observation of the process. In block 17, which is a sequence of memory cells in which, with discrete time f, the values of the function Res are recorded from block 16, the time of movement of the materials T / from the first to the second transverse is determined

drum section 1 as follows. The computer analyzes the numbers recorded in all memory cells and selects the largest of them. The time here is determined as follows:

.

W

f

 material movements

Where

M

(corresponds to the maximum

R (f) functions; .

N mc "x memory number, e

which recorded the most

number; ds - period of discrete recording

R (t) functions to follower

ness of memory cells.

In block 18, the distance E between: the first and second sections of drum 1 is divided by time ijvv from block 17. Moreover, distance K is the distance between sensors 12 and 13, which remains unchanged, and is stored in block 18 as a constant .

The application of the proposed method makes it possible to improve the quality of control of the thermal mode by disturbance, and consequently, more rational use of fuel, whose specific consumption is reduced by 1-1.5% at a given moisture content of the dried material.

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Fig.Z

Claims (1)

’METHOD FOR AUTOMATIC CONTROL OF DRYING OF BULK MA TERIAL by stabilizing the temperature in the mixing chamber by changing the fuel supply and changing the position of the exhaust fan gate according to the humidity of the dried material after the drying bar, characterized in that, in order to improve accuracy, measure the vacuum in the mixing chamber and the speed of movement of the material along the drying the drum and the position of the exhaust fan gate are additionally changed in accordance with the measured parameters.