JP2825726B2 - Control method for preventing accumulation and blow-by of coal drying and classification equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coal flow for preventing the formation of an initial fluidized bed and the accumulation and blow-through of coal during steady operation for stable coal transportation at the start of coal input and steady operation in a coal drying and classifying apparatus. The present invention relates to a method for controlling the thickness of a floating layer.

[0002]

2. Description of the Related Art As disclosed in the embodiment of Japanese Utility Model Application No. 02-010845, the fluidized-drying chamber has a superficial velocity of hot air of 0.1 to 3 m so that pulverized coal in coking coal is prevented from scattering as much as possible. In order to carry out drying and classification, the classifying chamber is set so that the superficial velocity becomes 4 to 10 meters / second so that the flow rate of hot air is determined by the driver.

[0003]

However, in the above-mentioned method, accumulation or blow-through occurs just below the charging port at the start of coal input, and the amount of input coal changes even during a steady operation, and the moisture fluctuation in the input coal occurs. However, the present invention has an object to solve the above-mentioned problem in that similar deposition or blow-through occurs when operating conditions such as change.

[0004]

According to the present invention, there is provided a method for controlling a flow rate of hot air in a fluidized-bed coal drying oven by measuring a fluidized-bed thickness meter of a fluidized-bed provided in a fluidized-conveying section of a fluidized-drying chamber immediately below a coal inlet. Open and close the flow control valve for hot air blown from the lower part of each divided layer and the flow control valve for hot air bypass blown from the side of the drying chamber near the coal input port with an appropriate operation order and an appropriate opening change amount. It is like that.

That is, the gist of the present invention is to provide a fluidized drying chamber for blowing hot air from below a horizontally arranged dispersing plate and fluidizing and drying the coal supplied on the dispersing plate.
A classifying chamber for classifying fine and fine coal and coarse coal, a hot air exhaust device provided at the upper part of the fluidized drying chamber and the classifying chamber, and a hot air bypass blowing device for introducing hot air just below the coal inlet. And, in a coal drying and classifying device composed of a coarse coal cutout device that discharges coarse coal, the value measured by a bed thickness gauge of a fluidized bed equipped in the fluidized conveyance section immediately below the coal input of the fluidized drying chamber. Therefore, by opening and closing the flow control valve of hot air blown from the lower part of each divided layer and the flow control valve of hot air bypass blown from the side of the drying room near the coal input port in an appropriate order and opening change amount A method for preventing coal deposition and blow-through of a coal fluid drying and classifying apparatus, wherein coal deposition and blow-through are prevented during formation of an initial fluidized bed and in steady operation thereafter.

[0006]

The operation of the present invention will be described with reference to FIG.
As a result of repeated experiments on how to prevent the occurrence of coal accumulation or blow-through immediately below the coal inlet at the start of coal input and during steady operation in a fluidized coal drying furnace, the layer thickness meter installed just below the coal input By opening and closing the hot air flow control valve of the divided fluidized drying chamber and the hot air bypass flow control valve that blows just below the coal input port in the proper order and in the proper amount by the measurement signal of We have obtained important knowledge for this facility that it is effective in controlling running process characteristics, accumulation or blow-through.

[0007] The sign of the accumulation is judged by the increase of the measured value of the layer thickness gauge 19, and the hot air bypass flow control valve 26 is first operated in the closing direction according to the judgment result of the accumulation phenomenon, so that the fine powder blown off by the hot air is reduced as much as possible. It is dropped to improve the flowability of coarse coal which tends to accumulate just below the inlet. If this operation does not eliminate the accumulation phenomenon, the hot air flow control valve 22 immediately below the inlet is opened to increase the hot air flow rate, and to further activate the fluidization and transportability. If the sedimentation phenomenon is not improved even after performing these operations, the transportability is impaired due to the accumulation of the next section from the inlet, so that the hot air flow control valve 23 of the next section is opened to increase the hot air flow rate, and the next section is heated. Activate fluid transportability.

Conversely, if the blow-through phenomenon is determined due to a decrease in the measured value of the layer thickness gauge 19, the hot air bypass control valve 2
6, the hot air flow control valves 22 and 23 immediately below the inlet and the next section are sequentially operated in the closing direction and in the direction opposite to the accumulation. By these operations, the occurrence of accumulation or blow-by caused by a change in operating conditions such as a change in the amount of input coal and a change in moisture in the input coal is prevented.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A control method for preventing coal deposition and blow-through in a fluidized-bed drying furnace according to the present invention will be described with reference to FIGS. First, regarding the prevention of deposition, the layer thickness meter 1 of the A section 15 was used.
9 is compared with the set value SHH set higher than the value of the layer thickness gauge 19 during normal operation, and a sign of a deposition phenomenon is predicted with the set value SHH or more, and the hot air bypass flow control valve 26 is set. The control mode of the exhaust gas temperature control device 12 is automatically switched from automatic to manual, and the opening degree at this time is set to αT
At step C, the timer is closed until the change amount reaches MTC at every timer set time TT1C. After waiting for TT2C after the change amount reaches the MTC, it is determined whether or not the measured value PVA of the layer thickness gauge 19 has become equal to or less than a value STH set lower than the set value SHH. If the value is equal to or less than the set value STH, the exhaust gas temperature control device 12 is returned to the automatic mode, and the automatic operation based on the exhaust gas temperature is performed.

Conversely, if the measured value PVA of the layer thickness gauge 19 does not fall below the set value STH even after waiting for TT2C, the control mode of the hot air flow control device 6 of the A section 15 is further switched from automatic to manual. The hot air flow control valve 22 is set to the timer setting time TA in αA0 steps from the opening at that time.
Open every 10 until the change amount reaches MA0. Wait for TA20 after the change amount reaches MA0, and set value SA
It is determined whether or not H or less. If the value is equal to or less than the set value SAH, the exhaust gas temperature controller 12 is returned to the automatic mode to perform automatic operation based on the humidity-temperature of the exhaust gas, and the hot air flow controller 6 in the A section 15 is returned to the automatic mode to perform the automatic operation. Do.

If the measured value PVA does not fall below the set value SAH even after the opening of the hot air bypass flow control valve 26 and the hot air flow control valve 22 is adjusted, the B layer 16
The control mode of the hot air flow control device 10 is switched from automatic to manual, and the hot air flow control valve 23 of the B section 16 is set to the timer setting time TB in αB0 steps from the opening at that time.
Open every 10 until the change amount reaches MB0. Wait for TB20 after the change amount reaches MB0, and set value SB
It is determined whether or not H or less. If the value is equal to or less than the set value SBH, the exhaust gas temperature controller 12 is returned to the automatic mode, and the automatic operation is performed based on the humidity-temperature of the exhaust gas.
Similarly, the hot air flow control device 6 in the layer 15 and the hot air flow control device 10 in the B layer 16 return to the automatic mode and perform the automatic operation.

The measured value PVA of the layer thickness gauge 19 of the A section 15 is set even if the opening of the hot air bypass flow control valve 26, the hot air flow control valve 22, and the hot air flow control valve 23 is adjusted. If the value does not fall below the value SAH, it is determined that control is impossible and an alarm is issued.

In the embodiment, the set value SHH is 980 Pa,
STH, SAH, and SBH are each 690 Pa, the step change amount αTC is −2%, and the step change amounts αA0 and αB.
0 is + 2% each, maximum change amount MTC, MAC, MB
C is 10% each, timers TT1C, TA10, T
B10 is 2 minutes, waiting time TT2C, TA20, TB20
Gave good results with each setting of 3 minutes.

Next, prevention of blow-through will be described. A
The measured value PVA of the thickness gauge 19 in the section 15 is compared with the set value SLL set lower than the value of the thickness gauge at the time of normal operation. The control mode of the exhaust gas temperature control device 12 is automatically switched from automatic to manual, and the flow control valve 26 is opened from the opening degree at this time in αT0 steps at every timer set time TT10 until the change amount becomes MT0. Timer setting time T after the change amount reaches MT0
After waiting for T20, it is determined whether or not the value is equal to or more than the STL set to a value higher than the set value SLL. If it is equal to or higher than the set value STL, the exhaust gas temperature controller 12 is returned to the automatic mode, and the automatic operation is performed based on the humidity-temperature of the exhaust gas.

On the other hand, even if it waits for TT20, A section 1
If the measured value PVA of the layer thickness gauge 19 of the fifth layer 5 does not exceed the set value STL, the hot air flow control device 6 of the layer A 19
Is switched from automatic to manual, and the hot air flow control valve 22 is closed from the opening degree at that time in the αAC step at every timer set time TA1C until the change amount becomes MAC. Waiting for the timer setting time TA2C after the change amount reaches MAC, the measured value PV of the layer thickness gauge 19 of the A layer 15 is measured.
It is determined whether or not A has exceeded the set value SAL. If the set value is equal to or higher than the set value SAL, the exhaust gas temperature control device 12 is returned to the automatic mode to perform the automatic operation based on the humidity-temperature of the exhaust gas, and is returned to the control mode of the hot air flow control device 6 to perform the automatic operation.

When the measured value PVA of the layer thickness gauge 19 of the A section 15 does not exceed the set value SAL even when the opening degree of the hot air bypass flow control valve 26 and the hot air flow control valve 22 of the A section 15 are adjusted. Further, the control mode of the hot air flow control device 10 in the B section 16 is switched from automatic to manual, and the amount of change becomes MBC for each timer set time TB1C in the αBC step from the opening degree at that time in the hot air flow control valve 23. To close. The change amount is MBC
, And waits for TB2C to determine whether the measured value PVA of the layer thickness gauge 19 in the A section 19 has become equal to or greater than the set value SBL. If the value is equal to or higher than the set value SBL, the exhaust gas temperature control device 12 is returned to the automatic mode, and the automatic operation is performed based on the exhaust gas temperature.
Similarly, the hot air flow control devices 6 and 10 return to the automatic mode and perform the automatic operation.

Even when the opening degree of the hot air bypass flow control valve 26, the hot air flow control valve 22, and the hot air flow control valve 23 is adjusted, the measured value PVA of the layer thickness gauge 19 of the A section 15 remains at the set value. If it does not exceed SLL, it is determined that control is impossible and an alarm is issued.

The layer thickness gauge 20 installed in the B section 16 of the fluidized drying chamber 1 is not used for control, and a measured value is displayed as a monitoring of the fluid transportability in the B section 16.

In the embodiment, the set value SLL is 294 Pa,
STL, SAL, SBL are each 690 Pa, the step change amount αT0 is + 2%, and the step change amounts αAC, αB
C is -2% each, maximum change amount MT0, MA0, MB
0 is 10% each, timer TT10, TA1C, T
B1C is 2 minutes, waiting time TT20, TA2C, TB2C
Gave good results with each setting of 3 minutes.

By implementing the present invention, as shown in Table 1, it was possible to greatly reduce the accumulation or blow-through of coal, which was generated by the sudden change in the amount of coal input and the moisture in the input coal in the conventional method.

[0021]

[Table 1]

[0022]

According to the present invention, the occurrence of deposition or blow-through can be greatly reduced, and a great effect is obtained in labor saving of operation and work. A very valuable new control method has been established for this process.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a control apparatus of a fluidized-bed drying furnace for coal in which a control method of the present invention is implemented.

FIG. 2 is a functional flowchart showing a control method of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Fluid drying room 2 ... Classification room 3 ... A section layer hot air supply pipe 4 ... Coal charging device 5 ... Dispersion board 6 ... A section hot air flow control device 7 ... D section hot air supply tube 8 ... D section hot air flow control device 9 ... Coarse-coal cutting device 10 ... B section hot air flow control device 11 ... C section hot air flow control device 12 ... Exhaust gas temperature control device 13 ... B section hot air supply pipe 14 ... C section hot air supply pipe 15 ... Flow drying oven A section 16 ... Fluid drying oven B section 17 ... Fluid drying oven C section 18 ... Fluid drying oven D section 19 ... A section layer thickness gauge 20 ... B section layer thickness gauge 22 ... A section hot air flow control valve 23 ... B section hot air flow control valve 24 ... C section hot air flow control valve 25 ... D section hot air flow control valve 26 ... Hot air bypass flow control Valve 27: bypass hot air line 28: bag filter PVA: measured value of A section layer thickness gauge (Pa) SHH: upper and lower limit set value (Pa) SLL: lower and lower limit set value (Pa) STH: when operating hot air bypass flow control valve Upper limit set value (Pa) STL ... Lower limit set value when operating hot air bypass flow control valve (Pa) SAH ... Upper limit set value when operating section A flow control valve (Pa) SAL ... Lower limit setting when operating A section flow control valve Value (Pa) SBH: Upper limit setting value when operating section B flow control valve (Pa) SBL: Lower limit setting value when operating section B flow control valve (Pa) αTC: Step operation amount when closing hot air bypass flow control valve ( ΑT0: Step operation amount when hot air bypass flow control valve is open (%) αA0: Step operation amount when A section hot air flow control valve is open (%) αAC: Step operation amount when A section hot air flow control valve is closed (%) αB0 ... Step operation amount when B section hot air flow control valve is open (%) αBC ... Step operation amount when B section hot air flow control valve is closed (%) MTC ... Maximum operation amount when the hot air bypass flow control valve is closed (%) MT0 ... Maximum operation amount when the hot air bypass flow control valve is open (%) MA0 ... Maximum operation amount when the A section hot air flow control valve is open (%) MAC ... Maximum operation amount when A section hot air flow control valve is closed (%) MB0 ... Maximum operation amount when B section hot air flow control valve is opened (%) MBC ... Maximum operation amount when closing B section hot air flow control valve (%) TT1C … Time interval of step change when hot air bypass flow control valve is closed (minutes) TT10… Time interval of step change when hot air bypass flow control valve is open (minutes) TA10… A section hot air flow Time interval of step change when control valve is opened (minute) TA1C: Time interval of step change when section A hot air flow control valve is closed (minute) TB10: Time interval of step change when section B hot air flow control valve is opened (minute) ) TB1C: Step change time interval when the B section hot air flow control valve is closed (minutes) TT2C: Waiting time after the maximum change when the hot air bypass flow control valve is closed (minutes) TT20: Maximum when the hot air bypass flow control valve is open Waiting time after change (minutes) TA20 ... Waiting time after maximum change when opening section A hot air flow control valve (minutes) TA2C ... Waiting time after maximum change when closing section A hot air flow control valve (minutes) TB20 ... Waiting time after the maximum change when the section B hot air flow control valve is opened (minutes) TB2C ... Waiting time after the maximum change when the section A hot air flow control valve is closed (minutes)

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C10L 5/00 B07B 4/08

Claims (1)

(57) [Claims] 1. A fluidized drying chamber for blowing up hot air from below a horizontally arranged dispersing plate to fluidize and dry the coal supplied on the dispersing plate, and to form fine and fine coal and coarse coal. A classifying chamber for classifying, a hot air exhaust gas discharging device provided at the upper part of the fluidized drying chamber and the classifying chamber, a hot air bypass blowing device for introducing hot air just below a coal inlet, and a coarse particle for discharging coarse coal In a coal drying and classifying device composed of a coal cutting device, blow in from the lower part of each divided layer based on the measurement value of the fluidized bed thickness gauge installed in the fluidized conveyance section just below the coal charge in the fluidized drying chamber. A hot air flow control valve,
By opening and closing the hot air bypass blowing flow control valve, which blows from the side of the drying chamber near the coal input port, in an appropriate order and opening amount, coal deposition and blow-through during the initial fluidized bed formation and subsequent steady operation A method for controlling coal deposition and blow-by of a coal fluid drying / classifying apparatus, characterized in that coal is prevented from flowing.