JPH09208050A - Powder and granular material blowing-control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize the blow by stably controlling the D/S differential pressure in blowing the powder and granular material, and to minimize the consumption of a gas to be used in the blow. SOLUTION: In a control device, the powder and granular material A, B stored in each pressure vessel is fluidized by the aeration gas 9 to be separately fed from pressure vessels 7, 8 through one blow line 4 connected to each pressure vessel, a pressure regulating valve 35 is adjusted in a powder and granular material-blowing facility to feed the powder and granular material into a tank 6 (a reaction vessel), the decompression is controlled to keep the differential pressure between the pressure vessel and the blow line 4 while a part of the gas in the pressure vessel is discharged into a discharge control line 14, and the blowing quantity of the powder and granular material to the tank 6 from the pressure vessel is controlled. An independently operable gas pressure replenishing means is provided in which the gas quantity for the pressure drop generated as at least the powder and granular material is discharged is replenished into the pressure vessel when the powder and grain is blown.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is suitable for use when a powder or granular material blow-in control device is blown, and particularly when a powdery or granular material is blown into a reaction vessel from one or more pressure vessels through one blowing line. The present invention relates to a powder and granular material blowing control device.

[0002]

2. Description of the Related Art The pressure difference between a pressure container (hereinafter, also referred to as a dispenser: D / S) containing a powder and granular material and a single blowing line connected thereto (hereinafter referred to as a D / S differential pressure). It is also used to blow powder particles into the reaction vessel through the blowing line. FIG. 5 schematically shows an example of the ironmaking equipment for blowing the powder or granular material.

In this blowing equipment, a carrier gas 1 is supplied to a blowing line 4 via a carrier gas line 2 or, if necessary, a blowing gas line 3 and finally connected to the blowing line 4. It is designed to be blown into the pot (reaction vessel) 6 from the tip of the lance. Then, in this equipment, two types of powder particles, A and B, are discharged from the respectively stored A-D / S7 and B-D / S8,
Since they are supplied to the middle of the same blowing line 4 through the pipes, these powder particles are carried by the carrier gas 1, respectively, and blown together with the carrier gas into the pan 6 from the tip of the lance 5 to be supplied. It has become.

The method of discharging the powdery particles from the above D / S (pressure vessels) 7 and 8 to the blow-in line 4 is substantially the same in any pressure vessel, so the case of A-D / S7 is representative. Then, the method will be described in detail.

An aeration gas 9 for bringing the powder or granules into a fluid state is introduced into the lower part of the D / S 7 through an aeration line 10 and mixed with the contained powder or granules. . In the upper part of the D / S7, a pre-pressurization line 12 used for supplying the pressurized gas 11 at the start of the pressurizing operation and the pressurizing operation are completed,
D / S differential pressure (pressure gauge 26
(The difference between the measured value of the pressure in the blowing line 4 by the pressure gauge and the measured value in the D / S by the pressure gauge 30) is less than the reference value, and the pressure difference is the same as the pressure line 13 used for controlling the pressure. Is above the reference value. Particularly, the exhaust line 14 used for pressure reduction control and the like is connected via a single pipe, and each of these lines can be operated independently.

In the above D / S7, after the D / S differential pressure reaches a predetermined value, the variable valve 27 is adjusted and, for example, 0.2 to 0.5 Nm ³ / min from the aeration line 10.
Blow gas at a flow rate of 10
To the outlet of the D / S
By discharging from the pot, the supply to the pot 6 at a target blowing speed is controlled.

That is, since the blowing speed of the granular material, the D / S differential pressure, and the opening degree of the variable valve 27 generally have a relationship as shown in FIG. 6, a target corresponding to the blowing speed is set. While setting the D / S differential pressure set value in advance and performing constant value control of the pressure control valve 35 by PID (proportional / integral / derivative) control so that the actual value of the D / S differential pressure becomes the target set value, Use the variable valve 27 so that the actual blow speed is set to the target blow speed set value by PID.
Control.

The constant value control of the D / S differential pressure is performed by the differential pressure control means including the pressure control valve 35, the pressure control line 13, the pressure control valve 33, the exhaust control line 14, the exhaust valve 34, etc. It is executed as follows.

That is, for example, as shown in FIG. 7, when the actual value of the D / S differential pressure is larger than the deviation L (reference value) lower than the differential pressure target value SV, the exhaust valve 34 is opened and the exhaust control line ( When the actual D / S differential pressure is less than the deviation L, the “pressure reduction system” 14 is used to perform “pressure reduction control” for controlling the D / S pressure control valve 35 while discharging a part of the gas in the D / S 7. , The D / S pressure adjusting valve 35 is controlled by opening the pressurizing valve 33 and using the pressurizing control line 13 to flow the pressurized gas into the D / S 7. The control method is switched according to the actual value of the S differential pressure.

[0010]

However, the above-mentioned conventional powdery-particle injection control device has a problem in control reliability. For example, there were the following problems when performing post mix injection. As in the equipment shown in FIG. 5, when two kinds of powders, A and B, are blown into one blowing line 4 to perform postmixing, the pressure of the blowing line 4 is A and B. It changes according to the total blowing speed of the powder. This pressure change in the blow-in line 4 appears remarkably when the blow-in speed is changed or when the blow-in becomes unstable due to some disturbance.

FIG. 8 shows how the state changes during such blowing. In order from the top, each blowing speed of A-D / S, B-D / S, each pressure, blowing line pressure, A-D / S,
It is a time change regarding each differential pressure of B-D / S.

In FIG. 8, the pressure reduction control method is used for A and B.
When both the powder and granules of B are blowing under the condition that the D / S differential pressure is normally controlled according to the target value, the change when the target blowing speed setting of B is increased from 40 kg to 60 kg at time t ₁ It is shown. At this time, since the actual blow speed of BD is increased, the blow line pressure is increased, and the actual differential pressure of AD is decreased accordingly. In this case, the blowing speed is controlled by the variable valve 27 at the same time, but since the blowing speed of the granular material A also decreases as the actual differential pressure decreases, eventually A-D.
The actual differential pressure of / S is less than the deviation L, and AD / S7
Then, the pressure reducing control may be changed to the pressure increasing control. When the pressure control is switched to the pressure control in this way, the actual AD pressure differential pressure is recovered and returns to the deviation L or more, and therefore the pressure control is switched again. At the same time, the blowing speed of the granular material A is recovered, and the blowing line pressure also rises with it. Then, the actual result of the B-D / S differential pressure decreases, and the A-D / S
As in the case of S, the BD / S differential pressure control is also switched from the pressure reduction control to the pressure control, and further from the pressure control to the pressure reduction control. Switching of both types of control is repeated,
Eventually, the blowing velocity converges, but in some cases it may not be converged only by repeating these.

Further, tuning of the PID parameter is performed at the time of switching between the pressure reducing control and the pressurizing control, but there is a problem that the control is not successful due to a response delay at the time of switching the control system due to the limitation of the tuning. Also, when switching is performed when the opening of the control valve 35 is large, rapid pressurization and rapid exhaust may occur, and conversely, when the opening of the control valve 35 is small, exhausting and pressurizing may take too long. was there.

Further, when the actual D / S differential pressure becomes negative, the gas flows back into the D / S, so that the blow from the tip of the lance is stopped for a moment, and the hot metal flows back into the lance, which is then inserted. It may become in a state and become unable to operate.

Therefore, considering the stability of the blow as the first,
The D / S differential pressure may be controlled only by decompression control while pressurizing the pressurization line 12 forcibly and pressurizing with more gas than necessary. In this case, of course, there is a problem that more gas is consumed than necessary.

[0016] These problems described above lead to the instability of the blowing speed, resulting in fluctuation of the blowing line pressure, which makes it impossible to perform stable D / S differential pressure control.

The present invention has been made to solve the above-mentioned conventional problems. The D / S differential pressure at the time of blowing a powder or granular material is stably controlled to stabilize the blowing of the powder or granular material. At the same time, it is an object of the present invention to provide a powdery or granular material blowing control device capable of suppressing the consumption of gas used for blowing to a minimum.

[0018]

DISCLOSURE OF THE INVENTION The present invention relates to a granular material contained in each pressure vessel from one or two or more pressure vessels via one blowing line connected to each pressure vessel. Is fluidized by aeration gas that is separately flowed in, and is then blown into the reaction vessel to be supplied by being blown into the reaction vessel, and the pressure difference between the pressure vessel and the blowing line is controlled by the pressure difference control means. In a powder-particle injection control device for performing a pressure-reduction control for maintaining a part of the gas in the pressure-reduction system while exhausting the gas to a pressure-reduction system, and controlling the powder-particle injection amount from the pressure vessel to the reaction vessel based on the pressure difference. , When blowing powder,
The pressure vessel is provided with a gas pressure replenishing means operable to replenish at least a gas amount corresponding to a pressure drop caused by the discharge of the granular material from the pressure vessel, the gas pressure replenishing means being operable independently of the differential pressure control means. As a result, the above problems have been solved.

That is, in the present invention, the gas pressure replenishing means constituted by a pressurizing line or the like capable of automatically adjusting the flow rate is provided so as to be operated independently of the original differential pressure control means. Therefore, the pressure drop caused by the discharge of the powder or granules from the pressure vessel during the blowing (in the same case as the equipment shown in FIG. 5, the powder or granules discharged from the D / S and The difference between the pressure drop due to the gas and the amount pressurized by the aeration gas flow rate) is used as the minimum gas replenishment amount, and the flow rate is controlled from the pressurization line to replenish and pressurize the D / S to obtain the D / S difference. Since it is possible to maintain the pressure at a constant positive pressure that is equal to or greater than the deviation L,
Since the D / S differential pressure control can always be performed by the pressure reducing control method, it is not necessary to switch between the conventional pressure reducing control and the pressure increasing control, and the D / S differential pressure control can be stabilized. Become. As a result, the amount of gas used for blowing the powder or granules can be reduced to a minimum, and the powder or granules can be stably blown.

[0020]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a schematic structure of a powder or granular material injection facility to which a powder or granular material injection control device according to an embodiment of the present invention is applied, and FIG. 2 shows the overall structure of the control device. It is the block diagram shown typically.

The equipment used in this embodiment is
As the gas pressure replenishing means that can be operated independently of the differential pressure control means for the D / S, except that the pressurized gas flow rate control valve 39 is attached to the pressurizing line 12, as shown in FIG. Are substantially the same. Although not shown in FIG. 5, reference numeral 38 is a cut-out valve used when the powder or granular material is stored in the D / S, and is normally closed after the powder or granular material is stored.

The control device of this embodiment comprises a powder and particle blowing facility 40 shown in FIG. 1 and a control computer (DD) for producing and outputting various control signals to the facility 40.
C) 50, a process computer 60 connected to the control computer 50, and an operation desk 70 for inputting information to the computer 50.

The control operation by the above-described powdery or granular material blowing control device will be described in detail below. After accepting the powders A and B from the cut-out valve 38 into the D / S 7 and 8, respectively, the aeration valve 37 is opened and the pressurizing valve 33 and the pre-aeration valve 33 are preheated so that each D / S has a predetermined pressure. Both the pressurizing valve 32 and the pressurizing valve 32 are opened to apply pressure. At this time, the D / S pressure control valve 35 and the pressurized gas flow rate control valve 39 are set to predetermined openings.

After the inside of the D / S reaches a predetermined pressure, the pressurizing valve 33 and the pre-pressurizing valve 32 are closed and the exhaust valve 34 is opened so that the D / S pressure becomes a predetermined pressure. The pressure control valve 35 is controlled. Control in this state is called D / S pressure control.

Next, the blowing operation is started. At that time, the carrier gas valve 24 and the blow gas valve 22 are opened, and the lance 5 is lowered in this state. At this time, the carrier gas flow rate control valve 25 is opened by a predetermined opening.
The control valve 25 is controlled so as to reach a target carrier gas flow rate set value according to the blowing speed after a lapse of a predetermined time by a timer from the opening operation of the outlet valve 28 described later.

When the lance 5 reaches a predetermined position, D
/ The outlet valve 28 of S7 is opened, and the blowing of the granular material is started. From the opening operation of the outlet valve 28 of the D / S 7, after a predetermined time has elapsed by the timer, the D / S pressure control is started.
Move to differential pressure control. This D / S differential pressure control is performed by a differential pressure control means including an exhaust control line (pressure reducing system) 14, an exhaust valve 34, a pressure control valve 35, etc.
The difference between the measured value by the blow line pressure gauge 26 and the measured value by the blow line pressure gauge 26, that is, the D / S differential pressure is set to a target D / S differential pressure set value which is predetermined according to the blow speed set value. This corresponds to performing the pressure reduction control while controlling the regulating valve 35 and discharging a part of the gas in the D / S 7 from the exhaust control line 14.

Simultaneously with the above D / S differential pressure control, the pre-pressurization valve 32 is opened to supplement the D / S pressure drop due to the blowing of the powder or granular material, and the D / S due to the blowing of the powder or granular material is opened. The gas flow rate for supplementing the difference between the S pressure drop and the D / S pressure pressurization by aeration is calculated by the computer (DDC) 50, and the calculated gas flow rate is at least supplemented to obtain the D / S.
The pressurized gas flow rate control valve 39 is controlled so that the differential pressure is always maintained at, for example, a positive pressure equal to or more than the deviation L, and the D / S is controlled.
7 is pressurized.

The above D / S differential pressure control is similarly executed for BD-8.

The method of calculating the gas flow rate of the supplemental amount, which is executed by the computer 50, will be described in detail later. The powder / particle blowing rate used in this calculation is the detection signal of the flow rate W from the D / S weight scale 29. Is calculated by moving average. Further, the variable valve 27 is controlled so that it becomes the set value of the powder and particle blowing speed. Then, in each D / S, when its own outlet valve 28 is open, that is, when the D / S itself is blowing, the D / S
The differential pressure is controlled only by the pressure reduction control performed by opening the exhaust control line 14.

The calculation of the gas flow rate set value for the replenishment when controlling the pressurized gas flow rate control valve 39, which is carried out by the computer 50, is performed by the equation for obtaining the required pressurized gas flow rate F as shown in FIG. It can be calculated by substituting the values obtained from the detected values of the D / S weight gauge 29, the blow line pressure gauge 26, and the D / S tank pressure gauge 30, which are field instruments. Here, a method of deriving the formula shown in FIG. 3 used for the calculation executed by the computer 50 will be described.

To properly control the D / S differential pressure, the D / S
It is necessary to exhaust the air from and to pressurize the D / S. However, one of the factors that make the D / S differential pressure unstable by the conventional method
The reason is that, as described above, the exhaust line and the pressurizing line are switched to perform two-way control with one control valve 35. Therefore, in consideration of the blowing stability as a first priority, the D / S differential pressure control may be performed by forcibly opening the pressurization line and only by reducing the pressure while pressurizing the gas flow more than necessary.
Economic loss is large. Therefore, control is performed to supplement the gas amount calculated according to the following idea.

The D / S pressure is determined by the amount of powder and particles discharged from the D / S and the amount of gas flowing into the D / S.
Therefore, the amount of gas required to replenish the amount of the D / S pressure that drops due to the particles discharged from the D / S and the amount of the gas discharged together with the particles are calculated from the blowing speed. ,
It is sufficient to supplement the amount of gas flowing into the D / S from the sum of these two, that is, the amount of gas obtained by subtracting the aeration gas.

The amount of gas required to replenish the pressure drop due to the particulate matter discharged from the D / S can be obtained from the following equation (1). Further, the amount of gas discharged together with the granular material can be obtained from the equation (2) by assuming the solid-gas ratio. Therefore, the required pressurized gas amount F1 can be obtained from the following equation (3). The F4 flushing gas flow rate included in the equation (3) corresponds to the aeration gas amount.

F2 = (Ws / γs) × (Ps + 1.0332) /1.0332 (1) F2: Gas flow rate required to hold the amount of pressure drop due to the particulate matter discharged from D / S (Nm ³ / min) Ws: Injecting speed of powdery particles (kg / min) γs: Bulk density of powdery particles (kg / m ³ ) Ps: D / S pressure (kg / cm ² G) F3 = Ws / (S / G x γg) (2) F3: Gas flow rate (Nm ³ / min) discharged together with the granular material.
) S / G: Solid-gas ratio γg: Carrier gas density (kg / m ³ ) F1 = F2 + F3-F4 (3) F1: Pressurized gas flow rate (Nm ³ / min) required at steady state F4: Flushing gas flow rate ( Nm ³ / min)

The gas flow rate given by the above equation (3) is the amount of gas required in a steady state. In a non-steady state such as when changing the blowing speed of the powder or granules, the target D / S differential pressure setting value changes, so it is necessary to add or subtract that amount. ) Equation.

F5 = [(Q−W / γs) × {(ΔP2−ΔP1) + (P02−P01)}] / T1 (4) F5: Required pressurized or depressurized gas flow rate (Nm ³
/ Min) Q: D / S effective volume (m ³⁾ W: D / S Weight (kg) [Delta] P2: D / S differential pressure after the change (kg / cm ²⁾ ΔP1: before the change D / S differential pressure ( kg / cm ² ) T1: Pressurization or depressurization time (min) P02: Blow line pressure after change (kg / cm ² G) P01: Blow line pressure before change (kg / cm ² G)

Therefore, in the non-steady state, the pressurized gas flow rate is given by the following equation (5). However, if this theoretical calculation equation is used as it is, it will be excessive due to instrument errors and response delays. There may be a shortage. Therefore, in order to prevent the powder and granular material from being unstable and to replenish the amount of gas that can be controlled with a small opening of the D / S pressure control valve, the actual pressurized gas flow rate set value F is set to the correction gas. It is calculated by the following equation (6) in which the amount is added. The equation (6) corresponds to the equation shown in FIG.

F6 = F1 + F5 (5) F6: Corrected pressurization flow rate setting value (Nm ³ / min) F = F6 + F7 (6) F: Pressurization flow rate setting value (Nm ³ / min) F7: Correction gas amount (Nm ³ / min)

Next, an example of various data in the steady state (before change) and the non-steady state (change) when the control is performed using the pressurized gas flow rate set value calculated in this embodiment,
It is shown in Table 1 below. Here, the solid-gas ratio was obtained from the solid-gas ratio in the blowing line, and then from the ratio of the cross-sectional areas of the blowing pipe and the variable valve 27.

[0041]

[Table 1]

FIG. 4 shows the result of performing the control according to this embodiment for the same example as in the case of FIG. From this result, it can be seen that the blowing speeds of AD / S and BD / S can be controlled stably.

As described above in detail, in this embodiment, the D / S pressurization gas flow rate required during the blowing of the powdery or granular material is obtained, and the D / S pressurization is performed while pressurizing the D / S. Since the S differential pressure control is performed, the control can be performed according to the D / S differential pressure set value. Further, since the amount of gas required for blowing was calculated and the pressure was increased, the amount of blow control gas was minimized. In addition, the stable D / S differential pressure enables stable blowing of the powder or granular material.

Although the present invention has been specifically described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the invention.

For example, in the above-mentioned embodiment, the case of the blowing equipment for mixing two kinds of powder and granules has been described, but the present invention is not limited to this, and a single blowing or a mixture of three or more kinds of powder and granules is possible. It may be a blow-in facility or a powder-grain blow-in facility by controlling the D / S internal pressure.

Further, the gas pressure replenishing means is not limited to the pressurizing line 12 whose flow rate can be adjusted by the adjusting valve 39 or the like, but may be a means for controlling the flow rate of the aeration gas, which is also used as the aeration means. Good.

[0047]

As described above, according to the present invention,
It is possible to stabilize the blowing by controlling the D / S differential pressure at the time of blowing the powder and granules, and to minimize the gas consumption amount used for the blowing.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a schematic configuration of a powder or granular material injection facility to which a powder or granular material injection control device according to an embodiment is applied.

FIG. 2 is a block diagram showing an outline of the above-mentioned powdery or granular material blowing control device.

FIG. 3 is an explanatory diagram showing a calculation procedure of a required pressurized gas flow rate set value according to the above embodiment

FIG. 4 is a diagram showing a control result according to the above embodiment.

FIG. 5 is an explanatory view showing an outline of a powdery or granular material blowing facility used for conventional control.

FIG. 6 is a diagram showing a relationship between a blowing speed, a D / S differential pressure, and a variable valve opening.

FIG. 7 is a diagram illustrating a conventional D / S differential pressure control method.

FIG. 8 is a diagram showing a control result by a conventional powder / particle injection control device.

[Explanation of symbols]

 1 ... Carrier gas 2 ... Carrier gas line 3 ... Blow gas line 4 ... Blow line 5 ... Lance 6 ... Pan 7 ... A / D / S 8 ... BD-S 9 ... Aeration gas 10 ... Aeration line 11 ... Addition Pressure gas 12 ... Pressurization line 13 ... Pressure control line 14 ... Exhaust control line 27 ... Variable valve 28 ... Outlet valve 35 ... Pressure control valve 39 ... Pressurized gas flow rate control valve

Claims (2)

[Claims] 1. An aeration gas in which powder particles contained in each pressure vessel are separately introduced from one or more pressure vessels via one blowing line connected to each pressure vessel. After being fluidized in, the powder and granules are blown into the reaction vessel, and the pressure difference between the pressure vessel and the blowing line is controlled by the pressure difference control unit to reduce the pressure of a part of the gas in the pressure vessel. Performing depressurization control to maintain while exhausting to the system, in the powder and granular material blowing control device for controlling the powder and granular material blowing amount from the pressure vessel to the reaction vessel based on the pressure difference, at the time of blowing the powder and granular material, The pressure vessel is provided with a gas pressure replenishing means operable to replenish at least a gas amount corresponding to a pressure drop caused by the discharge of the granular material from the pressure vessel, the gas pressure replenishing means being operable independently of the differential pressure control means. Control device for blown powder Place. 2. The powder / particle injection control device according to claim 1, wherein the gas amount corresponding to the pressure drop is calculated based on an actually measured powder / particle injection speed.