JPS6354513A - Multistage incinerator - Google Patents

Abstract

PURPOSE:To prevent high-temperature air within an incinerator from flowing out and to suppress the dispersion of heat to the minimum by closing cut-off valves provided at the flue of the incinerator and the rotary shaft cooling air outlet of a rotary stirring device during the period of stopping the incinerator. CONSTITUTION:It is confirmed that a furnace charge conveyor 8 is stopped and an incinerator 1 is set in a temperature holding step. After lapse of about one hour the starting of the temperature holding, when materials to be burnt are all discharge out of the incinerator 1, an exhaust gas fan 24 and a fuel pump 12 are stopped. After lapse of about one minute, an electric dust collector 23, a scrubber pump 22, a shaft cooling fan 19, and a furnace shaft 5 are all stopped, and further an incinerator outlet 28 is closed. Thereafter, when a shaft cooling air outlet valve 27 is closed, the incineratator 1 is put into a heat hold ing state. By these procedures. Since the fuel consumption is reduced by the stoppage of the burner and power is also reduced by the stoppage of respective apparatuses and further at the time of re-starting of the burner, lowering of the furnace temperature is less. Therefore, the heating time can be shortened and excellent re-starting of the furnace can be made.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to multi-stage incinerators used to incinerate sludge etc. generated in sewage treatment plants, and in particular, when the multi-stage incinerator is stopped for a short period of time such as at night. The present invention relates to a multistage incinerator control device that prevents a temperature drop and is suitable for reducing the power of exhaust gas treatment equipment, exhaust gas fans, etc., and the fuel consumption of burners.

[Conventional technology]

As described in Japanese Patent Application Laid-Open No. 59-24113, conventional equipment uses heat in high-temperature exhaust gas from combustion stages during multistage incinerator operation to heat combustion air through a heat exchanger, thereby saving energy. Although energy measures were taken, short-term shutdowns such as when the incinerator was shut down at night were not taken into account.

Sludge incinerators are expensive equipment, and in consideration of unforeseen circumstances and the future increase in materials to be combusted, the sludge incinerator has a processing capacity that is higher than the current required processing capacity, and it is not possible to operate it unmanned due to the use of fire. However, because it is difficult to secure staff at night, they are often shut down at night. As described above, incinerators often stop frequently for short periods of time, and it is necessary to consider not only energy saving during operation as in the above-mentioned conventional method, but also energy saving measures when the incinerator is stopped.

[Problems that the invention attempts to solve]

The above conventional technology reduces power consumption during the shutdown period of the multistage incinerator;
There were problems such as no consideration was given to reducing fuel consumption, and no consideration was given to energy saving in this case, which requires heating when restarting.

The purpose of the present invention is to reduce the amount of power and fuel used during the stop period of the multi-stage incinerator, prevent the generation of exhaust smoke from the multi-stage incinerator during the stop period, and reduce the temperature drop of the multi-stage incinerator. An object of the present invention is to provide a multistage incinerator device that reduces the amount of heating fuel used when starting combustion again.

[Means for solving problems]

The above purpose is to determine the completion of combustion of the to-be-combusted material after stopping the input of the to-be-combustible material into the multi-stage incinerator, and after the completion of combustion, to stop the exhaust gas fan, flue gas treatment equipment, and burner, and to This is accomplished by closing shutoff valves provided at the flue outlet and the shaft cooling air outlet to confine the high temperature air within the multistage incinerator.

[Effect]

According to the present invention, after the input of the materials to be burned into the multistage incinerator is stopped and after it is confirmed that the combustion of the materials to be burned is completed, the exhaust gas fan and the flue gas treatment equipment.

The burner is stopped and the shutoff valves installed at the flue outlet and shaft cooling air outlet of the multistage incinerator are closed, preventing the generation of exhaust smoke.
It is possible to reduce the power of the exhaust gas fan, etc., and prevent the temperature of the multistage incinerator from decreasing due to the outflow of high-temperature air inside the multistage incinerator.

〔Example〕

Next, one embodiment of the present invention will be described based on the drawings. FIG. 1 shows an embodiment of the present invention. In FIG. 1, a multistage incinerator 1 has a plurality of vertically arranged fences 2, and a rotating shaft 5 is disposed in the center thereof. This rotating shaft 5 is driven by an electric motor 22. At the top of the multi-stage incinerator 1, a furnace input feeder 6 is provided into which materials to be burned are input. Sludge is introduced by a belt conveyor 8 and then from a furnace input feeder 6. Furthermore, a gas outlet 4 for discharging exhaust gas and a shaft cooling air outlet 21 for discharging air within the rotating shaft are also provided at the top of the fired furnace 1. Furthermore, an ash discharge port 3 is provided at the bottom of the incinerator 1. The inside of the incinerator 1 is heated by hot air generated by the burner 15.

The burner is supplied with a fuel pump 1 from a fuel storage tank (not shown).
2. Fuel is supplied via a fuel control valve 13 and a flow meter 14 . The burner is also supplied with air from a burner blower 128. The amount of air supplied to the burner 15 can be adjusted as required, or can be supplied at a constant rate. In this embodiment, it is assumed that a constant amount is supplied. The fuel control valve 13 is connected to the temperature sensor 1 in the incinerator by the controller 17.
The temperature measured from step 6 is controlled to be the combustion temperature (about 750° C.). A stirring arm 7 is attached to each stage of a rotating shaft 5 located at the center of the incinerator 1, and an axial cooling fan 8 is provided to send air into the rotating shaft in order to cool the rotating shaft. Axial cold air is released directly into the atmosphere through the chimney. The exhaust gas from the incinerator 1 is processed by a scrubber pump 22 that spews out a caustic soda aqueous solution in the form of a shower in the flue gas treatment tower 20.
After coarse dust is removed in the electrostatic precipitator 23 and fine dust is removed in the electrostatic precipitator 23, the dust is discharged into the atmosphere from the chimney. An exhaust gas fan 24 is provided to suck exhaust gas, and the inside of the incinerator is made to have a negative pressure, so that the exhaust gas does not directly flow out from the incinerator 1 into the atmosphere.

Next, the operation will be explained. Furnace input feeder 6 of multistage incinerator 1
The materials to be burned are fed from the periphery to the center on each shelf 2 by the stirring arm 7 attached to the rotating shaft 5.
Further, they are sent alternately from the center to the circumference, and fall to the lower stage through holes provided in the gap between the rotating shaft 5 and the shelf 2 and the outer periphery of the shelf 2.

The objects to be burned are dried and burned as they fall one after another.

The combustible material becomes inorganic ash by combustion, is cooled as it moves to the lower stage, and is discharged from the discharge port 3.

The falling speed of the material to be burned is constant because the rotating shaft rotates at a fixed speed, and the time taken to complete combustion is a fixed value (about 1 to 2 hours). The rotating shaft 5 may be deformed due to the application of force for stirring the materials to be burnt and the high temperature inside the incinerator, so to prevent this deformation, cooling air is supplied to the rotary shaft 5. ing. In addition, the flue gas generated by the treatment of the materials to be combusted is sucked by the flue gas fan 24, washed with a shower of caustic soda aqueous solution in the flue gas treatment tower 20, and after removing fine dust in the electrostatic precipitator 23, the flue gas is sucked in by the flue gas fan 24. released.

Now, the control system when the incinerator temporarily stops combustion at night or due to a temporary shortage of materials to be combusted, and enters the heat retention process to maintain the temperature of the incinerator at a high temperature until the next combustion starts. The operation of 26 will be explained with reference to the flowchart shown in FIG.

First, in step S1, it is confirmed that the furnace charging conveyor is stopped. Next, in step S2, it is determined whether or not the incinerator 1 is in the heat retention process. If the incinerator 1 is in the heat retention process in step 3, the temperature inside the incinerator is During the period (1 hour in the case of this embodiment) until the combustion of the material to be combusted is completed, the exhaust gas fan, burner, etc. are all operated to carry out normal combustion, but in step S4, the furnace input feeder is stopped.

When one hour has elapsed since the start of heat retention and all the burnt materials have been discharged from the incinerator, the exhaust gas fan is stopped in step S5, and the fuel supply pump is stopped in step S6.

After the output of the exhaust gas fan stop command and the time required for the air flow from the incinerator to the exhaust gas fan to settle down (1 minute in this example), the electrostatic precipitator, scrubber pump, and axial cooling fan are activated in step 8.

All furnace shaft drives are stopped, and a command to close the incinerator outlet valve 28 is output.

After a period of time (in this embodiment, 30 seconds) for the flow of the shaft cooling air to settle down, a command to close the shaft cooling air outlet valve 27 is output, and the incinerator enters the heat retention state. In this way, after the input of the materials to be burned into the multi-stage incinerator is stopped, and after confirming that the combustion of the materials to be burned is completed, the exhaust gas fan is stopped to prevent exhaust smoke from leaving the incinerator. This has the effect of reducing fuel consumption by stopping combustion in the burner, and reducing power consumption by stopping fuel supply pumps, flue gas treatment equipment, and electrostatic precipitators. There is.

In addition, by closing the incinerator outlet valve and the shaft cooling air outlet valve, it is possible to prevent the temperature inside the incinerator from decreasing without heating by burner combustion. When restarting after stopping, the time required for heating can be shortened and a good restart can be achieved.

The inner surface of the incinerator 1 is usually covered with heat-resistant bricks,
It has a heat retention effect, and by closing the incinerator outlet valve and shaft cooling air outlet valve, the incinerator internal temperature decreases by approximately 100℃/1.
It can be kept down to about 2 hours (at night (PM7:
00-AM7: OO) After the warming operation, the next morning when the vessel was re-floated, the temperature had decreased by approximately 100°C. ).

〔Effect of the invention〕

As described above, according to the present invention, during the shutdown period, the flow path for discharging heat inside the incinerator to the outside, that is, the flue and the rotary shaft cooling air outlet, are sealed by shutting off, so that the inside is protected from heat. Dissipation can be suppressed to a minimum. As a result, it is possible to save energy.

[Brief explanation of the drawing]

Figure 1 is an equipment configuration diagram of one embodiment of the present invention, and Figure 2 is a diagram of the equipment configuration of an embodiment of the present invention.
It is an explanatory diagram of the operation of the incinerator control device shown in the figure. DESCRIPTION OF SYMBOLS 1... Incinerator, 20... Flue gas treatment tower, 23... Electrostatic precipitator, 24... Exhaust gas fan, 26... Incinerator control device, 27... Shaft cooling air outlet valve, 28 ...Incinerator exit valve.

Claims (1)

[Scope of Claims] 1. A multistage incinerator that has multiple shelves in the vertical direction, and in which sludge placed on the top shelf of the shelf is sequentially dropped to the lower stage using a rotary agitation device and is then combusted using a heating burner. In the above, the inside of the incinerator is sealed by closing the seal valves provided at the flue of the incinerator and the rotary shaft cooling air outlet of the rotary agitation device, respectively, during the incinerator's stop period. Features a multi-stage incinerator.