JP5432665B2 - Hot air drying method for inorganic materials - Google Patents

Description

  The present invention mainly relates to a drying method capable of drying an inorganic material to a desired moisture value accurately.

Conventionally, so-called municipal waste is dried and reused as solid fuel. As an example, the drying equipment S ′ used for this purpose, as shown in a skeleton diagram in FIG. 5, feeds the workpiece H or the like from the supply hopper 11 a ′ to the dryer 1 ′, and further counts from the burner 51 ′. Drying is performed by supplying hot air of Baidu and contacting with the workpiece H to obtain a dried product D.
As a method for obtaining a dried product D having a desired moisture value using such a drying facility S ′, the exhaust gas temperature exhausted from the dryer 1 ′ is measured, and this value becomes a constant target value. In addition, control for adjusting the amount of fuel used is performed (see, for example, Patent Document 1).

In such a method, the relationship between the amount of fuel used and the exhaust gas temperature with respect to the input amount of the workpiece H and the moisture value so that the dried product D has the target moisture value is obtained in advance, and the drying is performed from the exhaust gas temperature. The moisture value of the product D is estimated. For this reason, if the moisture region at the time of reduced rate drying tends to start from a high moisture value, such as organic materials such as municipal waste, if the drying is performed with the reduced rate drying region as the end point of drying, it is desired. It is easy to obtain a dried product D having a moisture value.
In addition, this method can be said to be feedback control since the temperature of the exhaust gas is a condition.

On the other hand, in the case of an inorganic material (steel making dust, etc.) where constant rate drying continues to a low moisture region, the dried product D may already be in a state where moisture is close to zero when the change in exhaust gas temperature appears. Many. For this reason, when applying the method disclosed in Patent Document 1 to a drying process in which the moisture value of the dried product D is required to be about 6%, the dried product D becomes too dry. In addition, it is necessary to provide a hydration step before supplying the dried product D to the next step, and it was impossible to avoid an increase in initial cost due to the installation of the apparatus and an increase in production cost due to the increase in the hydration step. .
In addition, the method of measuring the moisture value of the dried product D with a moisture meter and controlling the amount of fuel used based on the measured value is also a so-called feedback control. In the case of an inorganic material, a desired moisture value is greatly deviated or a defective moisture product is produced in a large amount.

Japanese Patent No. 3113780

  The present invention has been made from such a background, and is a novel inorganic material that can reliably dry a substance having constant drying to a low moisture region, such as an inorganic material, to a desired moisture value. The technical issue is to develop a hot air drying method.

That is, in the method for drying hot air of an inorganic material according to claim 1, the charging device is connected to the inlet of the drying cylinder in the dryer provided with the stirring blade, the hot air furnace is connected to the hot air inlet, and the outlet is connected to the outlet. In a method for obtaining a dried product by drying an inorganic material as a processing object using a drying equipment connected to a take-out conveyor and further connected to an exhaust fan at an exhaust port, the processing object supplied to the input port The material input speed V1 and the material moisture W1 are measured, and using these values and the dried product target moisture W20 of the dried product discharged from the discharge port, a moisture evaporation amount E in the drying cylinder is derived, Further, the moisture evaporation amount E can be realized by using a relational expression derived in advance between the moisture evaporation amount E and the dryer inlet temperature setting value T10 of the drying gas supplied to the hot air inlet. Calorie dry torso It is intended to determine the fuel flow rate set point M0 and the dryer inlet temperature set value T10 that is required to supply, to derive the heat transfer capacity coefficient C1 during actual operation of the dryer, the heat transfer capacity coefficient The number of revolutions of the drying cylinder and / or the number of revolutions of the stirring blade is changed so as to correct a deviation between C1 and a heat transfer capacity coefficient C0 derived in advance during a test operation. It is.

Moreover, the hot air drying method of the inorganic material according to claim 2 is based on the fuel flow rate setting value based on the dryer outlet temperature T21 and / or the dried product temperature T31 of the dry gas discharged from the exhaust port in addition to the requirements. It is characterized by correcting M0.
The above problems can be solved by using the configuration of the invention described in each of the claims as a means.

First, according to the first aspect of the present invention, by deriving the amount of water evaporation in the dryer, it becomes possible to supply the amount of heat commensurate with the amount of water evaporation into the drying cylinder at an appropriate temperature. Even an inorganic material that continues to a low moisture region can be reliably dried to a desired moisture value.
Moreover, since it is possible to prevent over-drying of the object to be processed, it is not necessary to provide a hydration step and the like, and an increase in initial cost and manufacturing cost can be avoided.
Furthermore, even if the material input speed fluctuates greatly or the properties of the object to be processed change greatly, the heat transfer capacity coefficient of the dryer determined by the operation performed in advance on a trial basis is obtained. By changing the number of revolutions of the drying cylinder and / or the number of revolutions of the agitating blade, the fuel flow setting value, the dryer inlet temperature setting value, the correction based on the dryer outlet temperature, and the correction based on the temperature of the dried product The control using can be continued, and the moisture value of the dried product can be set to a desired value.

  According to the second aspect of the present invention, the moisture value of the dried product can be set to a desired value even if the drying state of the object to be processed in the drying cylinder has changed for some reason.

1 is a skeleton diagram showing a drying facility that is an apparatus for carrying out the present invention. It is a graph which shows a water evaporation amount-fuel flow rate setting value characteristic. It is a graph which shows the moisture evaporation amount-dryer inlet temperature setting value characteristic. It is a graph which shows the moisture evaporation amount-dryer exit temperature normal value characteristic. It is a graph which shows a moisture evaporation amount-dry product temperature normal value characteristic. It is a skeleton figure which shows the drying equipment for implementing the conventional method.

  The best mode of the method for drying hot air of an inorganic material of the present invention is as shown in the following examples. However, it is possible to appropriately modify this example within the scope of the technical idea of the present invention. .

Hereinafter, an example of a drying facility to which the present invention is applied will be described based on the drawings, and an operation method of the drying facility of the present invention will be described together with the operating state of the facility.
FIG. 1 schematically shows a drying facility S, which comprises a dryer 1, a charging device 2, a take-out conveyor 3, a hot stove 5 and a control panel 6 as main members.
A charging device 2 is connected to the charging port 11 of the drying drum 10 of the dryer 1, a take-out conveyor 3 is provided below the discharge port 12, and a hot stove 5 is connected to the air supply port 13. The exhaust fan 14 is connected to the exhaust port 14.

Hereinafter, the members constituting the drying equipment S will be described in detail.
First, the dryer 1 will be described. A rotary drum dryer is applied as an example, and four support rollers are arranged on an appropriate base (not shown), and the support rollers are placed on the support rollers. A drying drum 10 which is a rotating drum is placed and provided.

The drying cylinder 10 is rotationally driven by a variable speed motor (hereinafter referred to as a motor 10m), and both ends of the drying cylinder 10 are closed with a boundary portion appropriately sealed by a lid member. .
In this embodiment, the rotating shaft 17a including the stirring blade 17 is driven to rotate by a variable speed motor (hereinafter referred to as a motor 17m) so as to penetrate the vicinity of the center of the drying cylinder 10.
A temperature sensor 16 is provided in the vicinity of the exhaust port 14, and the temperature sensor 16 measures the dryer outlet temperature T 21 of the dry gas A discharged from the exhaust port 14.
Further, in this embodiment, the supply port 11 is provided with a supply hopper 11a.

Next, the charging device 2 will be described. This device is arranged with the discharge end of the conveyor 21 facing the charging port 11 (in this embodiment, the supply hopper 11a) in the drying drum 10, and further the conveyor 21. The load cell 22 can measure the weight.
Further, the moisture value of the workpiece H on the conveyor 21 can be measured by a non-contact moisture meter 23 (optical type or the like).

Next, the take-out conveyor 3 will be described. This is provided with a screw conveyor at the bottom of the U-shaped trough, and the dried product D dropped into the U-shaped trough is sequentially discharged by the rotation of the screw conveyor.
Furthermore, the temperature (dry product temperature T31) of the dry product D transferred by the take-out conveyor 3 can be measured by a non-contact thermometer 31 (optical type or the like).

Next, the hot air furnace 5 will be described. In this furnace, the fuel F is burned by the burner 51 in the combustion furnace 50 lined with a refractory material, thereby heating the outside air sucked by the blower 52 to a desired temperature. Is an apparatus for generating the dry gas A. Note that a damper 57 whose opening degree is controlled by a control motor 57a is provided in a pipe line connecting the blower 52 and the combustion furnace 50.
The amount of fuel F supplied to the burner 51 is adjusted by the control valve 53, and the fuel flow rate M1 is measured by a flow meter 54 provided on the upstream side of the control valve 53.
Here, the output signal of the flow meter 54 is input to a flow rate regulator 58 provided in the control panel 6 and is compared with a fuel flow rate set value M0 described later, whereby the flow rate regulator 58 outputs the signal. A PID control signal is sent to the control valve 53 to adjust the opening degree of the control valve 53.
A temperature sensor 55 is provided in the vicinity of the supply outlet 50 a of the dry gas A in the combustion furnace 50, and the dryer inlet temperature T 11 of the dry gas A is measured by this temperature sensor 55, and an output signal thereof is sent to the control panel 6. While being input to the prepared temperature controller 56 and compared with a dryer inlet temperature setting value T10 described later, a PID control signal is sent from the temperature controller 56 to the control motor 57a, and the damper 57 The opening is adjusted.

  The output signals of the load cell 22, moisture meter 23, flow meter 54, temperature sensor 16, temperature sensor 55, and thermometer 31 are input to the control panel 6, and a programmable logic controller 6P (PLC) provided in the control panel 6 is further provided. Control signals are output from the flow controller 58 and the temperature controller 56 to the control valve 53, the control motor 57a, the motor 10m, and the motor 17m.

  The drying equipment S to which the present invention is applied has the above-described configuration as an example. Hereinafter, the operating state of the equipment will be described, and the hot air drying method for the inorganic material of the present invention will be described. In this embodiment, the fuel F is LNG. The workpiece H is an inorganic material such as steelmaking dust.

[Activation of drying equipment]
In drying the workpiece H using the drying equipment S to obtain a dried product D having a desired moisture value, first, the motor 10m is activated to rotate the drying cylinder 10, and the motor 17m is activated. Then, the stirring blade 17 is rotated. The take-out conveyor 3 is also activated.
Next, outside air is sucked by the blower 52, and the control valve 53 is further adjusted to supply the fuel F to the burner 51 and burn it to generate dry gas A having a predetermined temperature at the time of start-up. 10 is supplied.
At this time, the rotational speed of the drying cylinder 10 and the stirring blade 17, the flow rate of the fuel F, and the opening degree of the damper 57 (introduction amount of outside air) are set to values set for the start-up operation.

[Measurement of material input speed and material moisture]
Next, the supply hopper 11a and the conveyor 21 are activated to input the workpiece H into the dryer 1. At this time, the material charging speed V1 and material moisture W1 of the workpiece H supplied to the inlet 11 are set. taking measurement. Specifically, the control panel 6 derives the material charging speed V1 from the detected value of the load cell 22 by the programmable logic controller 6P, and further measures the material moisture W1 by the moisture meter 23.

[Derivation of moisture evaporation in drying cylinder]
In the programmable logic controller 6P, the material charging speed V1 [t / h] and the material moisture W1 [% W. B. ], The dry product target moisture W20 [% W. of the dry product D discharged from the discharge port 12]. B. ], The water evaporation amount E [t / h] from the workpiece H in the drying cylinder 10 is derived at regular intervals.
Specifically, calculation using the following formula (1) is performed. In this embodiment, as an example, the dry product target moisture W20 is set to 4 [% W. B. ], The material charging speed V1 is 25 [t / h], and the material moisture W1 is 12 [% W.]. B. ], The water evaporation amount E [t / h] was derived as shown below.

[Equation 1]
E = V1 × (1− (100−W1) / (100−W20)) (1)
= 25 × (1- (100-12) / (100-4))
= 25 × (1-88 / 96)
= 2.08 [t / h]

[Setting of fuel flow rate]
The amount of heat that can realize the moisture evaporation amount E [t / h] is supplied to the drying cylinder 10, and the fuel flow rate setting value M0 [m ³ N / h] required for this purpose is set. Derived using the following equation (2).
In the formula (2), the values of a and b are determined based on actually measured values obtained experimentally using the dryer 1. Here, the square symbols in FIG. 2 are points where measured values are dotted, and the straight line is a plot of theoretical formulas obtained from these measured values by the method of least squares. It is a line represented by a linear function of the water evaporation amount E.
In this example, a = 93.434 and b = 15.136.

[Equation 2]
M0 = a × E + b (2)
= 93.434 × 2.08 + 15.136
= 209.48 [m ³ N / h]

[Dry gas temperature setting]
Next, the dryer inlet temperature setting value T10 of the drying gas A generated by the hot stove 5 is set to a value that can realize the moisture evaporation amount E.
Specifically, it is derived using the following formula (3). In formula (3), the values of c and d are experimentally measured using the dryer 1 as shown in the graph of FIG. It is determined based on the actually measured value. Here, the square symbols in FIG. 3 are points where measured values are plotted, and the straight line is a plot of theoretical formulas obtained from these measured values by the least squares method, and the dryer inlet temperature setting value It is a line representing T10 as a linear function of water evaporation E.
In this example, c = 122.77 and d = 153.41.

[Equation 3]
T10 = c × E + d (3)
= 122.77 × 2.08 + 153.41
= 408.8 [° C]

Then, the operation of the dryer 1 is performed with the fuel flow rate setting value M0 = 209.48 [m ³ N / h] and the dryer inlet temperature setting value T10 = 408.8 [° C.] thus set as the setting values. Material moisture W1 = 12 [% W. B. ] To be processed H, dry product moisture W21 = dry product target moisture W20 = 4 [% W. B. The dried product D is obtained.
That is, based on the measured value (fuel flow rate M1) of the flow meter 54, the opening degree of the control valve 53 is controlled by the flow rate regulator 58, and the fuel flow rate M1 is the fuel flow rate set value M0 = 209.48 [m ³ N / h]. Further, the opening degree of the damper 57 is controlled based on the measured value (dryer inlet temperature T11) of the temperature sensor 55, and the dryer inlet temperature T11 is set to the dryer inlet temperature set value T10 = 408.8 [ ° C].
According to the present invention, by deriving the water evaporation amount E in the dryer 1, it becomes possible to supply the heat amount capable of realizing the water evaporation amount E into the drying drum 10, and the constant rate drying is low. Even when the material to be processed H is an inorganic material that continues to the moisture range, it can be reliably dried to a desired moisture value.
Further, since the dryer inlet temperature setting value T10 of the drying gas A is set to a value that can realize the water evaporation amount E in the dryer 1, the moisture value of the dried product D (dried product moisture W21) is reliably ensured. It can be set as a desired value (dried product target moisture W20).
For this reason, overdrying of the to-be-processed object H can be prevented, and it becomes unnecessary to provide a hydration process separately, and the increase in initial cost and manufacturing cost can be avoided.

[Fuel flow correction]
Then, the fuel flow rate setting value M0 is corrected based on the dryer outlet temperature T21 and / or the dried product temperature T31 of the dry gas A discharged from the exhaust port 14.
First, when the dryer outlet temperature T21 of the drying gas A measured by the temperature sensor 16 shows a value different from a planned temperature, that is, a normal value (dryer outlet temperature normal value T20), the following is shown. Such measures are taken at regular intervals.
That is, when the dryer outlet temperature T21 becomes lower than the dryer outlet temperature normal value T20, the fuel flow rate set value M0 is corrected in an increasing direction.
On the other hand, when the dryer outlet temperature T21 becomes higher than the dryer outlet temperature normal value T20, the fuel flow rate set value M0 is corrected in a decreasing direction.
The dryer outlet temperature normal value T20 is determined based on an actually measured value experimentally performed using the dryer 1, as shown in FIG. Here, the square symbols in FIG. 4 indicate the actual measurement values, and the curve is a plot of a theoretical formula obtained from these actual measurement values by the least square method. It is a line representing T20 as a quadratic function of the water evaporation amount E.
Further, in the formula (4), the values of e, f, and g are determined based on actually measured values experimentally performed using the dryer 1 as shown in the graph of FIG. In the example, e = 2.0408, f = 0.2766, and g = 71.692.
Accordingly, the dryer outlet temperature normal value T20 when E = 2.08 is obtained as follows.

[Equation 4]
T20 = e × E ² + f × E + g (4)
= 2.0408 × 2.08 ² + 0.2766 × 2.08 + 71.692
= 81.1 [° C]

When the dryer outlet temperature T21, which is a measurement value of the temperature sensor 16, shows a value that is different from the value of the dryer outlet temperature normal value T20 obtained by the above equation (4), the fuel flow rate is set according to the deviation. The value M0 is corrected.
For example, the deviation ± 10 ° C. of the dryer outlet temperature T21 from the dryer outlet temperature normal value T20 is made to correspond to ± 10% of the fuel flow rate setting value M0, and the dryer outlet temperature T21 is higher than the dryer outlet temperature normal value T20. If the temperature is higher by 3 ° C., the fuel flow rate setting value M0 is corrected by changing the setting by −3%. When the dryer outlet temperature T21 is 5 ° C. lower than the dryer outlet temperature normal value T20, the fuel flow rate set value M0 is changed by + 5% and corrected.
Even if the dry state of the workpiece H in the drying cylinder 10 is changed for some reason by taking such measures, the dry product moisture W21 is set to a desired value (dry product target moisture W20). It can be.

Further, when the temperature of the dried product D (dried product temperature T31) measured by the thermometer 31 shows a value different from the planned temperature, that is, a normal value (dried product temperature normal value T30), as shown below. Measures are taken at regular intervals.
That is, when the dry product temperature T31 becomes lower than the dry product temperature normal value T30, the fuel flow rate setting value M0 is corrected in the increasing direction.
On the other hand, when the dry product temperature T31 becomes higher than the dry product temperature normal value T30, the fuel flow rate setting value M0 is corrected in a decreasing direction.
The dry product temperature normal value T30 is determined on the basis of an actual measurement value experimentally performed using the dryer 1, as shown in FIG. Here, the square symbols in FIG. 5 indicate the actual measurement values, and the curve is a plot of a theoretical formula obtained from these actual measurement values by the least square method, and the dry product temperature normal value T30. Is a line represented by a quadratic function of the water evaporation E.
Further, in the formula (5), the values of h, i, and j are determined based on actually measured values experimentally performed using the dryer 1 as shown in the graph of FIG. In the example, h = −0.9524, i = 9.2857, and j = 57.917.
Accordingly, the dry product temperature normal value T30 when E = 2.08 is obtained as follows.

[Equation 5]
T30 = h × E ² + i × E + j (5)
= −0.9524 × 2.08 ² + 9.2857 × 2.08 + 57.917
= 73.1 [° C.]

When the dry product temperature T31, which is a measurement value of the thermometer 31, shows a value that is separated from the dry product temperature normal value T30 obtained by the above equation (5), the fuel flow rate setting value M0 is set according to the deviation. Is to correct.
For example, when the deviation ± 1 ° C. of the dry product temperature T31 with respect to the normal value T30 of the dry product corresponds to ± 10% of the fuel flow rate setting value M0, the dry product temperature T31 is 1 ° C. higher than the normal value T30 of the dry product temperature Corrects the fuel flow rate setting value M0 by changing the setting by -10%. When the dry product temperature T31 is 0.5 ° C. lower than the dry product temperature normal value T30, the fuel flow rate setting value M0 is changed by + 5% and corrected.
Even if the dry state of the workpiece H in the drying cylinder 10 is changed for some reason by taking such measures, the dry product moisture W21 is set to a desired value (dry product target moisture W20). It can be.

[Correction of heat transfer capacity coefficient]
As described above, in the present invention, the fuel flow rate set value M0 and the dryer inlet temperature are respectively calculated using the relational expressions (2) and (3) derived from the graphs shown in FIGS. The set value T10 is obtained, and the operation is controlled so that each set value is obtained.
Further, the fuel flow rate setting value M0 is corrected using the equations (4) and (5), which are the relational expressions derived from the graphs shown in FIGS.
Such control corresponds to the change in the workpiece H earlier than the feedback control, and can control the moisture fluctuation of the dried product D, and handles the workpiece H that does not allow a large moisture fluctuation. In such a case, a dry product D having poor moisture content is not generated.
However, when the material charging speed V1 varies greatly or the properties of the workpiece H change significantly, sometimes the drying is performed only by the control according to the equations (2), (3), (4), and (5). The product moisture W21 may deviate from the target moisture (dried product target moisture W20).
For this deviation, it is effective to perform control for correcting the deviation of the heat transfer capacity coefficients C0 and C1 of the dryer 1 as described below.

Here, the heat transfer capacity coefficient C1 of the dryer 1 in the actual operation (operation for manufacturing as a product) is the dryer inlet temperature T11, the dryer outlet temperature T21, the dried product temperature T31, and the workpiece H before being charged. The logarithm average temperature difference derived from the temperature, the internal volume of the drying cylinder 10 and the amount of heat derived from the fuel flow rate M1 are used to derive by a regular method. The formula used for the regular method is (heat transfer capacity coefficient) = (heat quantity) / {(internal volume of the dryer) × (logarithm average temperature difference)}.
Here, the measured value of the temperature of the workpiece H before the input is input to the programmable logic controller 6P by a temperature sensor (not shown). Further, the internal volume of the drying cylinder 10 is input to the programmable logic controller 6P in advance. The various derivations are performed at regular intervals by the programmable logic controller 6P.
On the other hand, since the heat transfer capacity coefficient C0 obtained by the operation performed experimentally using the dryer 1 is also input and set in advance in the programmable logic controller 6P, the heat transfer obtained by the actual operation is set as described above. Comparison with the capacity coefficient C1 is performed at a predetermined time by the programmable logic controller 6P, and a deviation of these heat transfer capacity coefficients C0 and C1, that is, a deviation is derived.
As shown below, the deviation of the heat transfer capacity coefficients C0 and C1 is obtained by changing the rotation speed of the drying drum 10 and / or the rotation speed of the stirring blade 17 so that the heat transfer capacity coefficient C1 becomes the heat transfer capacity coefficient C0. It is corrected to approach.

[Setting of rotation speed of drying cylinder]
First, an embodiment in which the rotational speed of the drying cylinder 10 is changed will be described. The motor 10m, which is a variable speed motor, is rotated by a drive frequency of 55 Hz by an inverter as an example, and the motor 10m is driven around this frequency. For example, the frequency is changed in a range of −10 to +10 Hz.
Specifically, when the heat transfer capacity coefficient C1 in actual operation is larger than the heat transfer capacity coefficient C0 during the test, the rotation speed of the drying cylinder 10 is increased.
On the other hand, when the heat transfer capacity coefficient C1 in actual operation is smaller than the heat transfer capacity coefficient C0 in the test, the rotational speed of the drying cylinder 10 is reduced.
Specifically, when the heat transfer capacity coefficient C1 in actual operation is larger than the heat transfer capacity coefficient C0 during the test by +80 kJ / (m ³ · h · ° C.), the rotational speed of the drying cylinder 10 is +8 Hz. The setting is changed to 63 Hz.
On the other hand, when the heat transfer capacity coefficient C1 in actual operation is as small as −40 kJ / (m ³ · h · ° C.) than the heat transfer capacity coefficient C0 during the test, the rotational speed of the drying cylinder 10 is set to −4 Hz and 51 Hz. The setting is changed to.
By changing the rotational speed of the drying cylinder 10 in this way, even if the material charging speed V1 fluctuates greatly, for example, the deviation of the heat transfer capacity coefficients C0 and C1 is corrected, and the equations (2) and ( 3) The control using the equations (4) and (5) can be continued, and the dried product moisture W21 can be set as the dried product target moisture W20.

[Setting of rotation speed of stirring blade]
Next, the case where the rotation speed of the stirring blade 17 is changed will be described. As an example, the motor 17m, which is a variable speed motor, is rotationally driven by an inverter at a driving frequency of 55Hz, and the motor 17m is driven around this frequency. For example, the frequency is changed in a range of −10 to +10 Hz.
Specifically, when the heat transfer capacity coefficient C1 in actual operation is larger than the heat transfer capacity coefficient C0 in the test, the rotational speed of the stirring blade 17 is decreased. When the heat transfer capacity coefficient C1 is larger than the heat transfer capacity coefficient C0 during the test by +50 kJ / (m ³ · h · ° C.), the rotational speed of the stirring blade 17 is set to −5 Hz, and the setting is changed to 50 Hz.
On the other hand, when the heat transfer capacity coefficient C1 in the actual operation is smaller than the heat transfer capacity coefficient C0 in the test, the rotation speed of the stirring blade 17 is increased, specifically, the heat transfer in the actual operation. When the capacity coefficient C1 is as small as −60 kJ / (m ³ · h · ° C.) than the heat transfer capacity coefficient C0 at the time of the test, the rotational speed of the stirring blade 17 is set to +6 Hz and the setting is changed to 61 Hz.
By changing the rotation speed of the stirring blade 17 in this way, even if the material charging speed V1 fluctuates greatly, for example, the deviation of the heat transfer capacity coefficients C0 and C1 is corrected, and the above equations (2) and ( 3) The control using the equations (4) and (5) can be continued, and the dried product moisture W21 can be set as the dried product target moisture W20.

S Drying equipment 1 Dryer 10 Drying drum 10m Motor 11 Input port 11a Supply hopper 12 Discharge port 13 Air supply port 14 Exhaust port 15 Exhaust fan 16 Temperature sensor 17 Stirring blade 17a Rotating shaft 17m Motor 2 Input device 21 Conveyor 22 Load cell 23 Moisture Total 3 Unloading conveyor 31 Thermometer 5 Hot air furnace 50 Combustion furnace 50a Supply outlet 51 Burner 52 Blower 53 Control valve 54 Flow meter 55 Temperature sensor 56 Temperature controller 57 Damper 57a Control motor 58 Flow controller 6 Control panel 6P Programmable logic controller A Dry gas D Dry product F Fuel H Processed object T10 Dryer inlet temperature set value T11 Dryer inlet temperature T20 Dryer outlet temperature normal value T21 Dryer outlet temperature T30 Dry product temperature normal value T31 Dry product temperature E Moisture steam The amount W1 material moisture W20 dried product target moisture W21 dried product moisture V1 material charging rate M0 fuel flow rate set value M1 fuel flow rate C0 heat transfer capacity coefficient C1 heat transfer capacity coefficient

Claims (2)

An input device is connected to the inlet of the drying cylinder in a dryer equipped with a stirring blade, a hot air furnace is connected to the hot air inlet, an extraction conveyor is connected to the outlet, and an exhaust fan is connected to the exhaust outlet. In a method for obtaining a dry product by drying an inorganic material as a processing object using a connected drying equipment, the material input speed V1 and material moisture W1 of the processing object supplied to the input port are measured, and these And the dry product target moisture W20 of the dry product discharged from the discharge port, the water evaporation amount E in the drying cylinder is derived, and the water evaporation amount E and supplied to the hot air blowing port. Fuel required to supply the drying cylinder with a heat quantity capable of realizing the water evaporation amount E using a relational expression derived in advance with the drying gas dryer inlet temperature setting value T10. Flow rate set value M0 Is intended to determine the fine drier inlet temperature set value T10, the dryer heat transfer capacity coefficient C1 at the time of actual operation is derived, and the heat transfer capacity coefficient C1, pre-derived test operation during the heat A method of drying an inorganic material with hot air , wherein the rotational speed of the drying cylinder and / or the rotational speed of the stirring blade is changed so as to correct a deviation from the moving capacity coefficient C0 . The hot air drying of an inorganic material according to claim 1, wherein the fuel flow rate setting value M0 is corrected based on a dryer outlet temperature T21 and / or a dried product temperature T31 of the dry gas discharged from the exhaust port. Method.

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