SU1404774A1 - Device for automatic regulation of annealing process in fluidized bed furnace - Google Patents

Abstract

This invention relates to the automation of fluidized bed furnaces. The purpose of the invention is to improve the quality of calcination by reducing fluctuations in the residence time of the material in the calcination zone. With a change in temperature in the layer measured by converter 1, an unbalance corresponding to this change appears at the outputs of the regulators 4, 5. The controller 4 actuates the actuator 6, which changes the position of the valve 7. And the amount of cheese loaded. When the temperature difference at the inlet of the regulator 5 is greater than the threshold for its operation, the latter through the mechanism 8 and the valve 9 changes the gas supply to the zone for combustion. 1 il. about

Description

"

The invention relates to the automatisation of fluidized bed furnaces and can be used in the iron and steel industry, the chemical industry, as well as in the production of building materials.

The purpose of the invention is to improve the quality of firing by reducing fluctuations in the residence time of the material in the layer.

The drawing shows a block diagram of the device.

The device contains a temperature measuring transducer 1 installed in the layer of the burning zone 2 and a secondary device connected to it

3. The first 4 and second 5 controllers are connected to the outputs of the latter. Regulator 4 contains the output of the first actuator 6, articulated with the valve 7 of the overflow device, controller 5 contains the output of the second actuator 8 with a feedback sensor (not shown) articulated with the valve 9 of the gas for combustion, To the second inputs Both controllers are connected by their outputs, setpoint 10. In addition, a feedback sensor of the actuator 6 is connected to the third input of the controller 5, The feedback sensor and the secondary device 3 are connected to the controller 5, and The one of this regulator is chosen higher than the regulator.

4, and its upper limit is chosen based on the ratio

IT „5

rC, {T-T,)

V g

K-p. K, Cj

45

de & t | - the threshold of operation of the additional "controller,

C, is the specific heat capacity of limestone, kJ / kg-K;

T is the temperature of the fluidized bed, K;

T, - temperature loaded

material. K; cf.

Gb — CaCOj content in limestone,%;

q is the amount of heat required for dissociation. 1 kg of limestone, kJ / kg; 2 degree of burning of limestone,%;

V is the gas consumption for the process,

55

0

0

five

five

0

five

0

five

R.

five

G - furnace productivity,

kg / h;

LT.d is the initial increment of the feedback sensor signal corresponding to a given temperature in the fluidized bed, K; D C - the maximum allowable increment of the residence time of the material in the layer, s; - material stays in

layer, with;

С - specific heat capacity of combustion products, kJ / m K; K - specific amount of exhaust gases at an air excess factor of about. eleven . The device works as follows.

In the initial state, the temperature in the zone 2 layer is equal to the specified one. As a result, the difference between the signals from the secondary device 3 and the setting device 10 at the input of the controller 4 is zero, and it does not affect the actuator 6. This mechanism and the valve 7 of the transducer are in an intermediate position corresponding to the middle of the control characteristic of the valve 7 and the nominal amount of material loaded into the zone, in which the residence time of the material in the layer and the quality of firing are equal to the specified,

In the initial state, the difference between the signals at the input of the controller 5, which is determined by subtracting the signal of the setpoint 10 in it from the total signal from the secondary device 3 and the feedback sensor of the actuator 6, is also zero. As a result, the regulator 5 does not affect the actuator 8 which, together with the valve 9, is in a position corresponding to the nominal gas flow rate for combustion,

With a change in temperature in the layer at the inputs of both controllers, an imbalance corresponding to this change appears. In this case, the main regulator 4 actuates the actuator 6, which begins to change the position of the valve 7 and the amount of material loaded into the zone towards eliminating the temperature change that has occurred. The state of the controller 5 in this case depends on the magnitude of the initial change in temperature T,

one

If & T «: lt, then the controller 5 remains in the same neutral state, and the temperature change is eliminated as a result of the described action of the main control system.

If, in addition to the main controller, the controller 5 is activated, the actuator 8 and the valve 9 are actuated. In this case, the temperature deviation is compensated for by a joint change in the material supply to the zone and the gas for combustion. Due to this, a smaller change in the amount of material is required, which contributes to the stabilization of the residence time of the material in the layer and to improve the quality of firing.

If THT is possible, then the controller 5 may be triggered some time after the start of operation of the main control system, especially in those cases when the temperature in the layer changes monotonously in one direction and the change in the residence time of the material in the layer reaches an acceptable value as a result of summing up the individual actions of the main regulator.

In all cases, due to the deistants of both control systems, the proposed device allows temperature stabilization in two ways: small deviations of the temperature

ki material, and large - more and the change in gas consumption for combustion. This eliminates significant variations in the residence time of the material in the layer.

All this allows to significantly improve the quality of firing.

 the invention

A device for automatic control of the firing process in a fluidized bed furnace, containing the first controller, to the inputs of which the unit is connected and through a secondary device - a temperature measuring transducer, and the output of which, through the first actuator, is connected to the material flow control valve, that, in order to improve the quality of firing by reducing fluctuations in the residence time of the material in the burning zone, it is equipped with a second regulator and a second actuator IOM, the inputs of the second controller are connected via a secondary device with a temperature transmitter, with zadatchi- com and sensor feedback of the first actuator, and The output from the second actuator connected to the gas supply valve

Pensiat change only boot-35 burning.

Claims (1)

Formula invented for automatic; control of the firing process in a fluidized bed furnace, comprising a first controller, to the inputs of which a setter is connected and, through a secondary device, a temperature measuring transducer, and the output of which through the first actuator is connected to a valve for controlling the flow of material into the firing aeon, characterized in that, by increasing quality of firing for reducing fluctuations in the time of the material in the firing zone, wife of the second controller and the second actuator, and the inputs of the second controller are connected through a secondary a device with a temperature measuring transducer, with a setter and a feedback sensor of the first actuator, and an output with a second actuator connected to the gas supply valve for combustion. the retention account is