JP3286853B2 - Ash Level Control Method in Stirred Incinerator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stirrer incinerator in which the surface of an incinerator is renewed by scraping on the hearth to enable uniform combustion, and in particular, the level of incineration ash accumulated on the hearth is detected. The present invention relates to a method for controlling an ash layer level so that an optimum operating condition can be realized.

[0002]

BACKGROUND OF THE INVENTION A circular stirred incinerator having a stirrer in the hearth that rotates horizontally while blowing air is used to treat human waste sludge,
It is widely used to incinerate sewage sludge.
In this stirred incinerator, the incineration material introduced from the furnace wall moves to the center of the hearth while being incinerated while being stirred by the stirrer, and the resulting incineration ash falls to the discharge chute provided in the center of the hearth. , Is pulled out by a screw conveyor or the like. The inside of the incinerator is usually operated at a negative pressure in order to prevent the incineration gas from leaking to the outside.

Therefore, if the incinerated ash is extracted too much, the so-called material seal due to the incinerated ash is broken, and the outside air flows into the incinerator through the screw conveyor and the discharge chute. There is a disadvantage that clinker is generated. Also, a decrease in the level of the ash layer reduces the stirring effect of the stirrer, and thus increases the combustion load of the incinerator. On the other hand, if the extraction of ash is neglected, the ash layer level rises, and the power of the agitator becomes overloaded. Therefore, for stable operation of the incinerator, it is necessary to keep the ash layer in the hearth at an appropriate level. However, since the inside of the hearth is at a high temperature of 700 ° C. or more, a normal level sensor cannot be installed, and it is difficult to visually check through an inspection window fitted with heat-resistant glass due to flame and dust.

Therefore, conventionally, a discharge weir is provided at the opening of the discharge chute, the height of the weir is adjusted, a damper is provided in the discharge chute, or the operation of the discharge conveyor is turned on and off for a fixed time. Attempts were made to do so.
However, the method using the discharge weir cannot adjust the lower limit of the ash layer level, and the damper method involves clinker clogging, which causes a problem of sealing performance. Further, the method of turning the discharge conveyor on and off with a timer does not follow the change in the amount of ash generated since the ash layer level is not detected.

Accordingly, the present applicant has filed Japanese Patent Application No. 3-209498.
Proposed a method of detecting pressure changes by providing a contact-type pressure sensor that constantly blows pressurized air inside the incineration ash discharge chute or above the opening of the incineration ash discharge chute or at a position facing the opening. . However, in this method, it takes time and effort to install a pressure sensor in an existing incinerator, and therefore, it has been desired to develop a simpler method for controlling the ash level.

[0006]

[Technical matters attempted to be developed] The present invention has been made in view of such a background, and has attempted to develop an ash layer level control method which can be easily adopted even in an existing incinerator. .

[0007]

Configuration of the Invention

That is, a ash layer level control method in a stirred incinerator according to a first invention of the present application comprises a rotating shaft rotated by the power of an electric motor, a plurality of arms provided for the rotating shaft, An incinerator having a stirring mechanism comprising a stirring rod attached to the arm floor so as to face the hearth, and an incinerator having an incineration ash discharging mechanism at the bottom of the furnace body. Controlling the discharge amount of the electric motor based on the power change of the electric motor ,
A mode for driving the screw provided in the incineration ash discharge mechanism
According to the power load of the electric motor in the stirring mechanism.
To periodically drive for a fixed time and stop for a fixed time.
By controlling to repeat, the discharge rate of incinerated ash
Controlling and adjusting the ash level on the hearth .

The ash layer level control method in a stirred incinerator according to the second invention according to the present invention is characterized in that in addition to the above requirements, a change in power of the electric motor is grasped by a current value, and incineration is performed based on the change in the current value. It controls the rate of ash discharge,
Transmits different signals to the motor according to the pointer of the ammeter
Thus, the drive interval of the motor is controlled. The present invention aims to achieve the above object.

[0009]

According to the present invention, the amount of incinerated ash discharged by the incinerated ash discharging mechanism is controlled based on the power change of the electric motor.
By detecting a power change corresponding to the ash layer level, an appropriate amount of incinerated ash can be discharged or the discharge can be stopped to maintain the target ash layer level.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on the illustrated embodiment. In describing the present invention, first, the structure of a circular stirring incinerator to which the present invention is applied will be schematically described, and then the features of the present invention will be described. First, reference numeral 1 denotes a circular stirring incinerator to which the present invention is applied, which includes a furnace 2a and a hearth 3 formed inside a furnace body 2 made of refractory, and a rotating hearth 3 A stirring mechanism 5 having a shaft 4 is provided, and an incineration ash discharging mechanism 6 is provided from the vicinity of the rotating shaft 4 to the outside of the furnace 2a.
Is formed.

An exhaust gas outlet 7 is formed in the upper part of the furnace body 2, an auxiliary burner 7a is provided in the middle, and an incineration material supply port 8 is formed in the middle of the inner wall of the furnace body 2. Is done.
An incinerator supply hopper 10 provided outside the furnace body 2 is connected to the incinerator supply port 8, and the incinerator A is supplied into the furnace 2a by a screw conveyor 11.

A circulating gas guide path 12 is formed at the bottom of the outer peripheral wall of the furnace body 2, while a plurality of circulating gas discharge holes 13 communicating with the circulating gas guide path 12 are formed at a constant interval at the bottom of the inner peripheral wall of the furnace body 2. Is formed. Incidentally, the circulating gas outlet 13 blows out the circulating gas tangentially to the furnace peripheral wall, and
a for forming a swirling flow in the combustion flame in a.
This circulating gas is supplied from a circulating gas inlet 14 formed in the circulating gas guide path 12.

Next, the stirring mechanism 5 has, for example, four arms 15 mounted on the rotating shaft 4 so as to project radially, and each arm 15 has a plurality of stirring rods 17 each having a plurality of blowout holes 16. Is attached downward so as to face the hearth 3. In addition, the rotating shaft 4, the arm 15, and the stirring rod 1
Each of the combustion blowers 7 has a hollow interior, and is formed continuously to form an air guide passage 18. The combustion blower 1 provided outside the furnace body 2 through the air guide passage 18.
The structure is such that the combustion air taken in from 9 is blown out from the blowout hole 16.

A sprocket 2 is provided at the lower end of the rotating shaft 4.
0 is provided, and a chain 23 is wound between the sprocket 20 and a sprocket 22 provided on an output shaft of a motor 21 provided in the vicinity, so that the power of the motor 21 is transmitted to the stirring mechanism 5 side. Has become.

Next, as shown in FIG. 3, the incineration ash discharging mechanism 6 has an opening 30 formed in the vicinity of the rotating shaft 4, from which an incineration ash discharging chute 29 extends obliquely downward, and incineration to the other end. The ash discharge conveyor 31 is connected. The incineration ash discharge conveyor 31 drives the screw 3
By rotating the incineration ash 2, the incineration ash B is transferred.

Next, as a configuration related to the present invention, a wiring 21a extends from the electric motor 21 to a power source.
An ammeter 40 is provided on the way, and a relative change in power consumption of the electric motor 21 under a constant voltage can be confirmed by a pointer on a display unit 41 thereof. Further, the ammeter 40 employs a meter relay as an example, and the display section 41 is divided into a B zone 42b, an A zone 42a, and a C zone 42c from the left side as shown in FIG. A low-level contact 43 indicating the lower limit of the ash layer level is provided between the A zone 42a and the A zone 42a.
Between the zone 42a and the C zone 42c, a high-level contact 44 indicating the upper limit of the ash layer level is provided.

The circular stirring incinerator 1 has the above-described structure, and the features of the present invention will be described below while describing the operation state of the device. First, the incinerated material A is put into the furnace 2a from the incinerated material supply port 8,
When ignited, vaporized gas and pyrolysis gas are generated from the incinerated material A as the temperature of the incinerated material A rises, and these are generated by the combustion air blown out from the outlet 16 of the stirring rod 17. Burn.

The incinerated material A is supplied to a stirring mechanism 5.
As a result, the surface is constantly renewed, and the combustible gas is generated on the hearth 3 on average. Further, the circulating gas is blown from the circulating gas outlet 13 so as to form a swirling flow in the combustion flame in the furnace 2a, and is completely burned in the upper furnace 2a.

After the gas is released, the solid mainly composed of carbon comes into contact with the combustion air while being stirred and mixed with the red ash, and gradually moves to the center of the furnace by so-called burning. In the vicinity of the opening 30 of the incineration ash discharge chute 6 in the center of the furnace,
The incinerated ash is cooled by the combustion air blown out from the blowout hole 16 of the stirring rod 17.

Here, the combustion state in the furnace will be schematically described. As shown in FIG. 4, the vicinity of the incineration material supply port 8 is a drying zone 45 in which moisture evaporates, from which a circulating gas flows. A main combustion zone 46 is formed outside on the downstream side. A red-hot carbide combustion zone 47 is formed inside the main combustion zone 46, and an incineration ash zone 48 is formed inside the zone.

As described above, the incineration ash B accumulates on the hearth 3.
As a result, the electric motor 21 receives a load of power according to the thickness of the incinerated ash B. This power burden appears on the pointer of the ammeter 40 under a constant voltage, and it is possible to know the ash layer level depending on whether the pointer indicates the A zone 42a, the B zone 42b, or the C zone 42c.

In the present invention, different signals are transmitted to the motor M in accordance with the pointer of the ammeter 40, and the driving interval of the motor M is controlled in accordance with each of these signals. Is controlled. That is, for example, when the pointer position is in the A zone 42a, as shown in FIG.
The motor M is controlled so as to periodically repeat the drive stop state for 20 seconds. Incidentally, when in this state, FIG.
Indicates that the level of the ash layer is controlled between H indicating the upper limit level and L indicating the lower limit level, as shown by a solid line in FIG.

When the pointer position is in the B zone 42b, as shown in FIG.
The motor M is controlled so that the drive stop state for 0 seconds is periodically repeated. By the way, when the pointer position is in the B zone 42b, the ash layer level is lower than the lower limit level L as shown by a dashed line in FIG. 5, so that the power load on the electric motor 21 is small and the current value is low. Therefore, the operation interval of the incineration ash discharge conveyor 31 is set to be longer than that in the case of the indicator of the A zone, that is, the incineration ash is discharged at a slower speed so that the ash layer level is increased.

Further, when the pointer position is in the C zone 42c, as shown in FIG.
Motor M so that the drive stop state for 2 seconds is periodically repeated.
Is controlled. Incidentally, when the pointer position is in the C zone 42c, the ash layer level is higher than the upper limit level H as shown by the broken line in FIG. 5, so that the power load on the electric motor 21 is large and the current value shows a large value. Therefore, the operation interval of the incineration ash discharge conveyor 31 is set to be smaller than that in the case of the pointer of the A zone, that is, the discharge speed of the incineration ash is increased so that the ash layer level is controlled to decrease.

In the present embodiment, the measuring range of the ammeter 40 is set to 0 to 5 A as an example. However, such analog information is converted into a digital signal, and a more precise control is performed by using, for example, a programmable controller. It is also possible to do.

[0026]

According to the present invention, since the amount of incinerated ash discharged by the incinerated ash discharging mechanism is controlled based on the power change of the electric motor, the destruction of the material seal due to excessive removal of the incinerated ash is reliably prevented. The temperature inside the furnace can be maintained and clinker can be prevented from occurring, and the overload state of the stirring power due to excessive accumulation of the incineration ash can be prevented, so that the stirring incinerator can be stably operated continuously.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view showing a circular stirring incinerator to which the present invention is applied.

FIG. 2 is a vertical sectional side view of the same.

FIG. 3 is an enlarged longitudinal side view showing the vicinity of the hearth.

FIG. 4 is a schematic diagram showing a combustion state in a furnace.

FIG. 5 is a front view schematically showing an ammeter.

FIG. 6 is a graph showing control waveforms of the incineration ash discharge conveyor when the pointers of the ammeter are in zones A, B, and C.

[Explanation of symbols]

 Reference Signs List 1 circular stirring incinerator 2 furnace body 2a furnace 3 hearth 4 rotating shaft 5 stirring mechanism 6 incineration ash discharging mechanism 7 exhaust port 7a combustion burner 8 incinerator supply port 10 incinerator supply hopper 11 screw conveyor 12 circulation gas guide path Reference Signs List 13 circulating gas outlet 14 circulating gas inlet 15 arm 16 outlet 17 stirring rod 18 air guideway 19 combustion blower 20 sprocket 21 electric motor 21a wiring 22 sprocket 23 chain 29 incineration ash discharge chute 30 opening 31 incineration ash discharge conveyor 32 screw 40 Ammeter 41 Display 42a A zone 42b B zone 42c C zone 43 Low level contact 44 High level contact 45 Drying zone 46 Main combustion zone 47 Carbide combustion zone 48 Incineration ash zone A Incineration material B Incineration ash H Ash layer level Upper limit L Lower limit of ash level M Over data

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-62-294803 (JP, A) JP-A-4-157,000 (JP, A) JP-A-63-84600 (JP, A) JP-A-4- 340009 (JP, A) JP-A-61-17826 (JP, A) JP-A-59-92332 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F23J 1/00 F23G 5 / 28,5 / 00

Claims (2)

(57) [Claims] A rotating shaft that is rotated by the power of an electric motor;
A stirrer mechanism including a plurality of arms provided for the rotating shaft and a stirrer bar attached to the arm so as to face the hearth is provided inside the furnace body, and an incineration ash discharging mechanism is provided at the bottom of the furnace body. In the incinerator, the amount of incineration ash discharged by the incineration ash discharging mechanism is controlled based on a change in the power of the electric motor .
A motor for driving the screw is connected to the stirring mechanism.
For a certain period of time and at a certain
Control to periodically repeat the drive stop during
Control the incineration ash discharge rate by
Ash level control method in a stirred incinerator, characterized in that the ash level is adjusted . 2. A change in power of the electric motor is grasped by a current value, and a discharge rate of incineration ash is controlled based on the change in the current value.
And different signals depending on the ammeter guidelines.
The ash layer level control method in the agitation incinerator according to claim 1 , wherein the driving interval of the motor is controlled by transmitting the signal to the motor .