JP2825734B2 - Control device for coal drying / classifying device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for forming a proper fluidized bed and stably transporting it in a coal drying / classifying apparatus, and more particularly to a bed thickness measurement and bed thickness control of a fluidized bed and an exhaust gas temperature control. Things.

[0002]

2. Description of the Related Art FIG. 3 shows a conventional control device, in which coal is charged from a coal charging device 4 and a fluidized drying chamber 1 is provided.
The coal is dried while forming a fluidized bed and transported in the classifier 2. The fine and fine coal is blown up in the classification chamber 2 while the coarse coal is formed in the lower part and transported to the cut-out device 9 on the outlet side Is done. The operation of the flow of coal and the flow of hot air for drying and classifying the coal are performed in a fluidized drying chamber 1 and a classifying chamber 2 separately. The fluidized-drying chamber 1 is supplied with hot air from one hot-air supply pipe 3 and has an empty space of 0.1 to 3.0 m / sec to such an extent that the fine coal in the coal charged from the coal input device 4 is not scattered. Hot air is blown from the dispersing plate 5 at the tower speed to carry out drying and fluidization and transportation of the coal. The setting of the hot air flow rate for this purpose is performed by operating the hot air flow control valve 22 of the hot air supply pipe 3. In the classifying chamber 2, the setting operation of the hot air adjusting valve 25 of the hot air supply pipe 7 is performed so that the superficial superficial velocity is within the superficial superficial velocity of 4 to 10 meters / second. The setting operation of each hot air flow rate is frequently performed by the driver who determines the amount of coal input, the moisture in the coal, the particle size distribution of the coal, and the like. Classification room 2
The coarse coal which has been flow-conveyed from is deposited at the discharge section where the cutout control device 9 is located, and the driver estimates the appropriate cutout amount based on the input coal quantity, the classification ratio of fine and fine coal and coarse coal, and the like. The setting operation of the cutout control device 9 is performed.

[0003]

However, when a hot air flow rate operation is performed by a single hot air supply device with respect to a fluidized drying chamber, it is difficult to obtain an appropriate superficial velocity distribution in the flowing and conveying direction. Due to frequent transport troubles and fluctuations in the amount of coal charged, moisture, etc., there is a problem that the setting operation of the hot air flow rate must be frequently performed.
Further, in the conventional method, it is difficult to take a means for preventing the adhesion of the fine coal blown up in the discharge pipe due to the condensation of the moisture in the exhaust gas and the promotion of corrosion due to the condensation of the highly corrosive components.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has been made to reduce the operational troubles by improving the fluid transportability of a fluidized drying chamber and preventing dew condensation in exhaust gas, and to save labor for monitoring operation. For the purpose of

[0005]

According to the present invention, there is provided a control apparatus for a coal drying / classifying apparatus in which a hot air supply control of a fluidized drying chamber is divided into three parts to improve a fluid conveyance property, and an upstream of the three divided fluidized drying chambers. The two sections on the side are provided with a thickness gauge for measuring the thickness of the fluidized floating bed for grasping fluidization, and the flow by automatically changing the hot air flow rate of the hot air supply pipe based on the measurement value of the thickness gauge is measured. It is equipped with a layer thickness control device and an exhaust gas temperature control device that enable stabilization of transportation, labor saving of operation operation, and adjustment of exhaust gas temperature by blowing hot air directly below the coal inlet. That is, the gist of the present invention is as follows.

[0006] (1) A fluidized drying chamber in which hot air is blown up from below a horizontally arranged dispersing plate to convey the coal supplied onto the dispersing plate while fluidizing it, and to which a discharge pipe for discharging the hot air is connected to the upper portion. And a classifying chamber for blowing fine and fine coal while classifying the coal conveyed from the fluidized drying chamber further to the discharge path side to classify the coal into fine and fine coal and coarse coal, In a coal drying / classifying device comprising a coarse-grained coal cutting device for discharging coal and a hot air supply device for supplying hot air from the bottom of the fluidized drying chamber and the classifying chamber, a fluidized drying chamber divided into three A hot air flow rate control device, a layer thickness gauge that measures the layer thickness of the fluidized floating layer of the coal being flow-conveyed, and an exhaust gas temperature control device that adjusts the exhaust gas temperature by introducing hot air just below the coal inlet A control device for a coal drying / classifying device, characterized in that:

(2) The flow rate of hot air supplied to the fluidized drying chamber is
The control of the coal / classification apparatus according to the above (1), further comprising a hot air flow rate control device capable of automatically changing a hot air flow rate based on a measured value of a layer thickness meter provided in the fluidized drying chamber. apparatus.

[0008]

According to the present invention, the three divisions of the hot air flow rate control in the fluidized drying chamber further improve the fluidized drying property, and the thickness gauge contributes as an index of the flow conveying condition, and the measured value of the thickness gauge can be increased. If the measured value is small, it is predicted as a blow-by phenomenon and acts to decrease the hot air flow rate. The hot air flow rate control of each section divided into three sections ensures that the value of the hot air flow rate of each section is within the appropriate control range in order to ensure the quality of coal drying and classification while maintaining proper fluidized bed formation and transportability. It is performed by the operation setting according to the driver's judgment so as to be within. Changes in the flow state due to changes in operating conditions such as changes in coal input and fluctuations in moisture in coal are detected by a layer thickness gauge in each section, and the hot air flow rate is automatically adjusted to eliminate accumulation or blow-by for each section. change. Condensation of water in the exhaust gas is prevented by increasing the flow rate of hot air blown just below the coal input and raising the temperature of the exhaust gas when the temperature of the exhaust gas falls below the condensation temperature.

[0009]

An embodiment of the present invention will be described with reference to FIG. In order to obtain more stable fluid transportability in the fluidized drying chamber 1, the hot air flow rate supply of the fluidized drying chamber 1 is divided into three sections 15, 16 and 17, and in particular, the A section 15 in which the fluid transport trouble often occurs. And B section 16
A layer thickness meter 1 for measuring the layer thickness of the fluidized floating layer of coal
9 and 20, taking into account operating conditions such as the amount of input coal and moisture in the coal, the flow rate can be transported and the index F of the air volume calculation equation of equation (1) can be set so as not to cause accumulation or blow-by. The appropriate value is determined by the driver for each section, and the hot air flow control devices 6, 10 and 1 of the fluidized drying chamber 1 are set.
1 is set for each. The flow control device 6,1
0 and 11 are controlled by operating the hot air flow rate so that the calculated value of the index F becomes a set appropriate value. As described above, in particular, regarding the flow control devices 6 and 10 of the A section 15 in which coal accumulation or blow-through troubles occur frequently,
The set value of the index F of each section is automatically changed based on the measured values of the thickness gauges 19 and 20.

F = (K · ρ · U ² ) / 2 · g (1) In the equation (1), K is the aperture ratio of the dispersion plate 5, ρ is the specific gravity of the hot air obtained by the equation (2), g Is the acceleration of gravity, and U is the actual flow velocity of the discharge from the hot air nozzle holes on the dispersion plate, which is obtained by the equation (3).

Ρ = ρ _O {273 / (273 + T)} (2) U = Q {(273 + T) / 273} / a · 3600 (3) In the equation (2), ρ _O is the specific gravity of hot air in the reference state, In the equations (2) and (3), T is the temperature of the hot air, Q in the equation (3) is the hot air flow rate, and a is the total nozzle area.

In the classifying chamber 2, that is, the hot air flow control device 8 in the D section 18, an appropriate value determined by the driver using the similar index F is set and operated in the control device 8, so that stable flow conveyance / classification characteristics are obtained. The hot air flow rate is controlled so as to be obtained.

An embodiment of the control will be described in detail with reference to section A. The hot air flow rate control device 6 determines the set value FSA with the above-described index F based on the hot air flow rate according to the driver's judgment so that appropriate flow conveyance and drying characteristics can be obtained from operating conditions such as the amount of coal input and moisture in the coal. The control unit 6 sets the calculated value FPA according to the equation (1) to the set value FSA.
The hot air flow rate QA supplied to the A section is controlled by the hot air flow control valve 22 so that

Next, the control by the layer thickness gauge will be described with reference to FIG. Measured value PVA of layer thickness gauge 19 of A section 15
Exceeds the set value PHA, the aforementioned set value FSA for the hot air flow control device 6 is increased by + α, and the timer setting T
After waiting for 1A time, it is determined whether or not the measured value PVA is equal to or less than the set value PHA. If the measured value PVA is equal to or less than the set value PHA, the control is continued as it is. The measured value PVA is equal to the set value PH.
If the measured value PVA becomes equal to or less than the set value PHA, the set value FSA is further increased by + α, and the set value FSA becomes equal to or less than the set value PHA. Continue control with the stop. When the set value FSA has reached the upper limit set value FSAH, the control for changing the set value based on the signal of the layer thickness gauge is stopped, and an alarm is generated as control is impossible.

Conversely, when the measured value PVA of the layer thickness gauge 19 becomes smaller than the set value PLA, the set value FS of the hot air flow controller 6 is set.
A is decreased by -α, and after waiting for the timer set time T2A, if the measured value PVA becomes equal to or more than the set value PLA, the control is continued as it is. The value FSA is repeatedly decreased in -α steps, and the measured value PVA of the thickness gauge 19 is obtained.
Becomes equal to or more than the set value PLA, the control is continued while maintaining the state at that time. Set value FSA is lower limit set value FSA
When it reaches L, the control of changing the set value by the signal of the layer thickness gauge is stopped, and an alarm is generated as control is impossible.

In the above control operation, the measured value PVA of the layer thickness gauge 19 which has become equal to or more than the set value PHA within the set time of the timer set time T1A becomes equal to or less than the set value PHA and again becomes equal to or more than the PHA. However, the set value FSA is not added until the set time T1A has elapsed. Also, even if the measured value PVA of the layer thickness gauge 19 which has become equal to or less than the set value PLA within the set time of the timer set time T2A becomes equal to or less than the set value PLA and becomes equal to or greater than the PLA again, the set time T2A elapses. Does not subtract the set value FSA.

In the embodiment of section A, PHA =
880 Pascal (hereinafter referred to as Pascal = Pa), PL
A = 560 Pa, + α = + 2%, −α = −2%, FSA
H = 2000, FSAL = 1500, T1A = 5 minutes, T
Good results were obtained with a setting of 2A = 5 minutes.

In the embodiment of the B section 16 as well, the hot air flow rate control and the automatic change of the set value of the index F by the layer thickness gauge can be performed in exactly the same manner as the A section 15, and the values of various settings are the same as those of the A section. Good results were obtained.

Next, an embodiment of the exhaust gas temperature control will be described. A bypass hot air line 27 acting as a bypass is provided for the fluidized drying chamber 1 and the classifying chamber 2, and an exhaust gas temperature control device 12 and a hot air flow control valve 26 are provided. Measured value H from detection end 30
The exhaust gas temperature controller 12 opens and closes the hot air flow control valve 26 so that the PV becomes the target value HSV set by the driver. During the control by the humidity HPV at the bag filter outlet, when the temperature TPV at the bag filter inlet at the temperature detecting end 29 becomes equal to or higher than the upper limit set value TSVH, the exhaust gas temperature control device 12 is switched from automatic to manual and the control by the humidity HPV is performed. Is stopped, β is subtracted from the value MV of the operation output at that time for the flow control valve 26, and the control valve 26 is operated in the closing direction by β to suppress the abnormal rise of the bag filter inlet temperature, thereby reducing the bag filter. Prevents burning of the filter cloth inside. Bag filter entrance temperature TPV is set value TS
When the temperature returns to VL or less and returns to normal, the exhaust gas temperature controller 12 is returned to the automatic mode and normal humidity control is continued.

In the embodiment, TSVH = 100 ° C., TSVH
Good results were obtained with L = 90 ° C. and β = 2%.

[0021]

According to the present invention, the operation for operating the coal drying / classifying apparatus is greatly reduced, and a great result is achieved in labor saving. In addition, problems such as coal accumulation or blow-through during fluid conveyance are reduced, and abnormal temperature rise and dew condensation in the exhaust gas pipe line are also eliminated.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a control apparatus for a fluidized-flow coal oven of the present invention.

FIG. 2 is a schematic functional conceptual diagram of the control device of the present invention.

FIG. 3 is a schematic configuration diagram of a control device of a conventional coal fluidized-bed drying furnace.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Fluid drying chamber 16 ... Fluid drying furnace B section 2 ... Classification chamber 17 ... Fluid drying furnace C section 3 ... A section hot air supply pipe 18 ... Fluid drying furnace D section 4 ... Coal charging device 19 ... A section layer thickness gauge 5 ... Dispersion plate 20 ... B section layer thickness gauge 6 ... A section hot air flow control device 21 ... Missing 7 ... D section hot air flow control valve 22 ... A section hot air flow control valve 8 ... D section hot air flow control device 23 ... B section hot air flow Control valve 9 ... Coarse-coal cutting device 24 ... C section hot air flow control valve 10 ... B section hot air flow control device 25 ... D section hot air flow control valve 11 ... C section hot air flow control device 26 ... Hot air bypass flow control valve 12 ... Exhaust gas temperature control device 27 bypass hot air line 13 section B hot air supply pipe 28 bag filter 1 The aperture ratio of ... C section hot air supply pipe 29 ... temperature detectors 15 ... fluidized drying oven A section 30 ... temperature detectors F ... hot air flow indicators (no unit) Q ... hot air flow rate (Nm ³ / h) K ... dispersion plate (No unit) T: Hot air temperature (° C) ρ _O : Specific gravity of reference condition (No unit, ratio to air) ρ: Specific gravity of use condition (No unit, Ratio to air) g: Acceleration of gravity (m / S ²⁾ U: Actual discharge velocity of the hot air nozzle on the dispersion plate (m / S) a: Total area of the nozzle (m ² ) FSA: Set value of index F of section A FPA: Index F by hot air flow rate (QA) of section A
FSAL ... Upper limit value of index F in section A FSAL ... Lower limit value of index F in section A QA ... Measured value of hot air flow rate in section A (Nm ³ / h) PVA ... Measured value (Pa) PHA: High-side set value of layer thickness control of A section (Pa) PLA: Low-side set value of layer thickness control of A section (P
a) + αA... A section FSA addition amount (%) −αA... A section FSA subtraction amount (%) T1A... control timer setting time (FSA subtraction) for A section A FSA subtraction Set time of control timer at time (minutes) HPV: Measured value of exhaust gas humidity at outlet of bag filter (relative humidity%) HSV: Measured value of exhaust gas humidity at outlet of bag filter (relative humidity%) β: Open of hot air bypass flow control valve Degree of change (%) TPV: Measured value of exhaust gas temperature at bag filter inlet (° C) TSVH: Upper limit set value of exhaust gas temperature at bag filter inlet (° C) TSVL: Lower limit set value of exhaust gas temperature at bag filter inlet (° C)

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) C10L 5/00 B07B 4/08

Claims (2)

(57) [Claims] 1. A fluidized drying chamber in which a hot air is blown up from below a horizontally arranged dispersion plate to convey the coal supplied on the dispersion plate while fluidizing the coal, and a discharge pipe connected to an upper portion thereof for discharging the hot air. A classifying chamber for blowing up fine and fine coal while classifying fine coal into fine coal and coarse coal while further transporting the coal conveyed from the fluidized drying chamber to the discharge path side; In the coal drying and classifying apparatus composed of a coarse coal cutting device for discharging coal and a hot air supply device for supplying hot air from the bottom of the fluidized drying chamber and the classifying chamber, the fluidized drying chamber divided into three It has a hot air flow control device, a layer thickness gauge for measuring the layer thickness of the fluidized floating layer of the coal being flow-conveyed, and an exhaust gas temperature control device for adjusting the exhaust gas temperature by introducing hot air just below the coal inlet. Characteristic control device for coal drying and classifying device. 2. A hot air flow rate control device which enables automatic change of a hot air flow rate based on a measured value of a layer thickness meter provided in the fluidized drying chamber, wherein the hot air flow rate supplied to the fluidized drying chamber is provided. The control device for a coal and classification device according to claim 1, wherein