JP2003230875A - Waste treatment plant - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a waste treatment plant which can reduce the operating cost by reducing the cost required for removing dioxins from exhaust gas. <P>SOLUTION: This waste treatment plant is provided with a pyrolysis reactor 12, a combustion melting furnace 13 for receiving pyrolyzed gas, a carbon residue selected from a pyrolysis residue to burn them, an exhaust gas treatment part 6 for treating exhaust gas with a bag filter 17, an activating means 30 for supplying a part of the carbon residue to an activator 35 without feeding it to the combustion melting furnace 13 and for activating the carbon residue in the activator 35 by carbon dioxide gas supplied into the activator 35, and an activated carbon residue supply means 31 for supplying the activated carbon residue to the bag filter 17. The supply of carbon dioxide gas to the activator 35 is performed in a way where exhaust gas discharged from the activator 35 is collected, oxygen is supplied to the collected exhaust gas to generate carbon dioxide gas, and the carbon dioxide gas is returned and fed to the activator 35. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is provided with a pyrolysis reactor for pyrolyzing waste into a pyrolysis residue and a pyrolysis gas, and the pyrolysis gas and the carbon residue selected from the pyrolysis residue are provided. The present invention relates to a waste treatment plant provided with a combustion melting furnace for receiving and burning, and an exhaust gas treatment unit for treating exhaust gas with a bag filter.

[0002]

2. Description of the Related Art Conventionally, in the above waste treatment plant,
In order to remove dioxins from the exhaust gas, a bag filter is provided in the exhaust gas treatment section and an activated carbon supply section that supplies commercially available activated carbon to the bag filter is provided so that the activated carbon adsorbs dioxins.

[0003]

However, according to the above-mentioned conventional structure, since the activated carbon is supplied to the bag filter, there is a problem that the cost required for the activated carbon becomes high and the operating cost becomes high.

An object of the present invention is to provide a waste treatment plant capable of reducing the operating cost by reducing the cost required for removing dioxins from exhaust gas.

[0005]

The constitution, action and effect of the invention according to the constitution of claim 1 are as follows.

[Structure] In the waste treatment plant described at the beginning, a part of the carbon residue is replaced by
Supplying to an activator without going to the combustion melting furnace side, an activating means for activating in the activator by the carbon dioxide gas supplied to the activator, and activated carbon supplying activated carbon residue to the bag filter A residue supply means is provided to supply carbon dioxide gas to the activator, recover exhaust gas discharged from the activator, and generate carbon dioxide gas by supplying oxygen to the recovered exhaust gas. It is configured to be supplied back to the activator.

[Action] The activating means supplies a part of the carbon residue selected from the pyrolysis residue to the activator without directing it to the combustion melting furnace side, and the carbon dioxide supplied to the activator. Activated in gas in the activator. And
The activated carbon residue supply means supplies the activated carbon residue to the bag filter of the exhaust gas treating section.

Like the activated carbon, the activated carbon residue is likely to adsorb dioxins. By supplying this carbon residue to the bag filter, dioxins in the exhaust gas can be removed.

[0009] For example, in the technique of supplying activated carbon to the bag filter to adsorb dioxins in the exhaust gas to the activated carbon, the cost required for activated carbon increases, but according to the configuration of claim 1, activated carbon is supplied to the bag filter. It doesn't have to be, and you don't have to pay for activated carbon.

Further, activated carbon and charcoal-activated carbon residue may be supplied to a bag filter to remove dioxins in the exhaust gas. In such a case, a small amount of activated carbon is required for activated carbon. Cost can be reduced.

When activating the carbon residue in the activator,
At the beginning of operation, carbon dioxide gas is supplied from a carbon dioxide gas storage part such as a gas tank to the activator, but thereafter, carbon dioxide gas generated by the activation means is supplied.

More specifically, most of the exhaust gas discharged from the activator is composed of carbon monoxide (CO) and carbon dioxide gas (CO ₂ ). Therefore, the exhaust gas discharged from the activator is recovered and recovered as exhaust gas. Oxygen is supplied to react carbon monoxide in the exhaust gas with oxygen to generate carbon dioxide gas. As a result, most of the recovered exhaust gas can be converted to carbon dioxide gas. Then, this carbon dioxide gas is supplied as an activating gas back to the activator.

As described above, it is sufficient to supply the carbon dioxide gas from the carbon dioxide gas storage section into the activator only at the beginning of the operation, so that the cost required for the carbon dioxide gas can be reduced.

[Effect] Therefore, it was possible to provide a waste treatment plant capable of reducing the operating cost by reducing the cost required for removing dioxins from exhaust gas.

Structure and operation of the invention according to the structure of claim 2
The effects are as follows.

[Structure] In the structure of the present invention according to claim 1, a neutralization processing unit for neutralizing the recovered exhaust gas is provided.

[Operation] In addition to the same operation as the operation according to the first aspect of the present invention, a high temperature corrosion of the pipeline and the activator is provided because the neutralization processing section for neutralizing the recovered exhaust gas is provided. Can be prevented.

[Effects] Therefore, in addition to the same effects as the effects according to the first aspect of the invention, the waste disposal plant can be operated smoothly and the number of maintenances can be reduced. Could be provided.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a pyrolysis gasification and melting plant which is a processing plant for general waste such as household waste and industrial waste such as car shredder dust and electric appliances.

The pyrolysis gasification and melting plant comprises a pretreatment facility 1, a pyrolysis facility 2, a pyrolysis residue sorting facility 3, a high temperature combustion melting facility 4, a boiler power generation facility 5, and an exhaust gas treatment facility 6. Next, each facility will be described.

[Pretreatment facility 1] The waste stored in the waste pit 7 is crushed by a crusher, and the crushed waste is sent to the thermal decomposition facility 2 by a transport device or the like.

[Pyrolysis facility 2] The waste from the waste pit 7 is conveyed and supplied to the pyrolysis drum 12 (corresponding to a pyrolysis reactor), and the heating gas is supplied to the pyrolysis drum 12 by the heating gas supply means 102. To do. Then, while indirectly heating the waste with this heating gas, the waste is pyrolyzed into a pyrolysis gas of about 450 ° C. and a pyrolysis residue in an oxygen-free or low-oxygen atmosphere, and the pyrolysis gas is burned at a high temperature described later. It is sent to the melting furnace 13 and the pyrolysis residue is sent to the pyrolysis residue sorting facility 3.

[Pyrolysis Residue Sorting Equipment 3] Pyrolysis Drum 1
The pyrolysis residue from 2 is sent to the pyrolysis residue sorting device 99 by a vibration feeder 70 or the like.

In the thermal decomposition residue sorting device 99, the iron sorted by the magnetic separator 91 is recovered in the iron yard 96, and the aluminum sorted by the aluminum sorter is collected in the aluminum yard 97.
To collect.

Then, the pyrolysis residue after the iron, aluminum, etc. are selected is crushed by a crusher 93. The foreign matters of the crushed ones are collected in the foreign matter yard 98, the carbon residues other than the foreign matters are sent to the carbon residue silo 61 through the first carbon residue pipeline 32, and the carbon residue in the carbon residue silo 61 is removed by the carbon residue blower 48. It blows into the high temperature combustion melting furnace 13 of the high temperature combustion melting equipment 4 from the furnace top side through the second carbon residue pipeline 33.

[High Temperature Combustion and Melting Facility 4] Carbon residue, pyrolysis gas, and dust dust are blown into the high temperature combustion and melting furnace 13 from the furnace top side, and these are swirled and burned. The incinerated ash and dust collected will be melted and continuously discharged from the bottom of the furnace.

[Boiler power generation equipment 5] Exhaust gas is cooled in the boiler radiation zone, and is brought to a uniform temperature in the evaporation tube group, and then sent to the heated steam group. The boiler 18 recovers heat from the steam, and the turbine 94 / generator 95 recovers it as electricity.

[Exhaust Gas Treatment Facility 6] A gas cooling tower 21 for the exhaust gas from the boiler 18, a first bag filter 17, and a second bag filter 22 are provided, and a chimney 25 for exhausting the exhaust gas treated by these devices is provided. is there.

Then, a dust silo 89 for accommodating the dust collecting dust from the boiler 18, the gas cooling tower 21, and the first bag filter 17 is provided, and the dust collecting dust in the dust silo 89 is passed through the dust blower 49 through the dust pipe line 50. As described above, the high temperature combustion melting furnace 13 is configured to be blown from the furnace top side.

A slaked lime supply mechanism 56 for supplying slaked lime to the second bag filter 22 is provided. The second bag filter 22 can remove HCl and SOx.

Further, a part of the carbon residue of the carbon residue selected from the thermal decomposition residue in the thermal decomposition residue selection equipment 3 is supplied to the activator without being directed to the high temperature combustion melting furnace 13 side, An activating means 30 for activating in the activating furnace 35 by the carbon dioxide gas supplied to the activating furnace 35 (corresponding to an activating device), and an activating carbon residue supplying means 3 for supplying the activated carbon residue to the first bag filter 17.
1 and are provided.

Explaining the activating means 30, the first carbon residue pipe 32 and the third carbon residue pipe 34 of the thermal decomposition residue sorting facility 3 are branched, and the weighing conveyor 52 is connected to the third carbon residue pipe 34. It is provided. Then, the carbon residue from the weighing conveyor 52 is activated by the activation furnace 3
It is configured to accept 5.

At the branch portion of the first carbon residue pipeline 32 and the third carbon residue pipeline 34, there are a first state in which carbon residue is flown to the carbon residue silo 61 side and a second state in which it is flown to the activation furnace 35 side. A switching damper 51 that can be switched is provided. Further, the activation furnace 35 is provided with a stirrer 36, a temperature measuring device 37, a temperature controller 38, and an electric heater 39, and a gas tank 41 (corresponding to a carbon dioxide gas storage portion) for storing carbon dioxide is connected to the inside of the activation furnace 35. is there.

Exhaust gas from the activation furnace 35 is exhaust pipe 40.
Through the high temperature combustion melting furnace 13. Further, the exhaust pipe 40 is branched to collect exhaust gas. Then, carbon dioxide is generated by supplying oxygen to the recovered exhaust gas, and the carbon dioxide is returned to the activation furnace 35 and supplied.

More specifically, the branch pipe 104 branched from the exhaust pipe 40 is connected to the activation furnace 35, and a sodium bicarbonate packed column 100 as a neutralization processing unit for neutralizing the recovered exhaust gas with sodium bicarbonate is provided in the middle of the branch pipe 104. And the baking soda packed tower 10
A reaction tower 101 for reacting carbon monoxide in exhaust gas with oxygen is connected to a branch pipe portion on the downstream side of 0,
A gas suction fan 103 is provided in the branch pipe portion downstream of 1.

With the structure described above, carbon dioxide gas as an activating gas is supplied from the gas tank 41 to the activating furnace 35 at the beginning of the operation. When the exhaust gas is discharged from the activation furnace 35, the exhaust gas is driven by the gas suction fan 103 to branch the pipe 10.
4 and neutralize through a baking soda packed column 100. Then, in the reaction tower 101, oxygen is supplied to the exhaust gas to react them. Most of the exhaust gas discharged from the activation furnace 35 is carbon monoxide (CO) and carbon dioxide (CO ₂ ), and carbon monoxide among them reacts with oxygen to become carbon dioxide. As a result, most of the recovered exhaust gas can be carbon dioxide gas. The activation furnace 35 uses this carbon dioxide gas as the activation gas.
Supply back to.

As a result, the carbon dioxide gas as the activating gas need only be supplied from the gas tank 41 into the activating furnace 35 only at the beginning of operation, and the cost required for the carbon dioxide gas can be reduced.

The activated carbon residue supply means 31 stores a conveyor 42 that conveys the activated carbon residue, an activated carbon residue storage tank 43 that stores the carbon residue from this conveyor 42, and a carbon residue in this tank 43. The air transport mechanism 55 blows the activated carbon residue blower 45 through the activated carbon residue conduit 46 into the exhaust gas conduit 44 upstream of the first bag filter 17.

A fixed amount supply mechanism 53 is provided on the bottom side of the activated carbon residue storage tank 43 so that a fixed amount of activated carbon residue can be blown into the exhaust gas pipeline 44 in a fixed amount.

With the above structure, the switching damper 51
Is switched to the second state side, the carbon residue is supplied to the weighing conveyor 52, and the set amount of carbon residue measured by the weighing conveyor 52 is supplied to the activation furnace 35.

Next, carbon dioxide gas is uniformly supplied from the gas tank 41 into the activation furnace 35 through the diffuser pipe. Further, the stirrer 36 is operated to stir so that the carbon dioxide gas and the carbon residue are contacted uniformly. The carbon residue is heated by the electric heater 39. In this case, the temperature measuring device 37 and the temperature controller 38 raise the temperature in the furnace at a predetermined temperature increase rate of 750 to 900 ° C.

Since the supply of carbon dioxide gas into the activation furnace 35 is as described above, its explanation is omitted. After activating the carbon residue, the electric heater 39 is turned off to cool the carbon residue. Then, the cooled carbon residue is supplied to the activated carbon residue storage tank 43, and the set amount of carbon residue is supplied to the air transport mechanism 55 side by the fixed amount supply mechanism 53 on the tank bottom side, and the set amount is set by the air transport mechanism 55. The carbon residue of the above is supplied to the exhaust gas pipeline 44 on the upstream side of the first bag filter 17.

Like the activated carbon, the activated carbon residue is likely to adsorb dioxins. By supplying this carbon residue to the first bag filter 17, the dioxins in the exhaust gas can be removed. . The carbon residue having adsorbed dioxins is screened together with dust from the filter cloth of the first bag filter 17, stored in the dust silo 89, and blown into the high temperature combustion melting furnace 13 from the furnace top side.

[Other Embodiments] The recovered exhaust gas may be neutralized with something other than baking soda.

The heating of the activation furnace may be heating using an electric heater or more, for example, kerosene or a gas burner.

The present invention can be applied to a waste treatment plant provided with a fluidized bed type pyrolysis furnace for pyrolyzing waste, instead of the pyrolysis drum 12. The fluidized bed type pyrolysis furnace is generally called a pyrolysis reactor.

The numerical values mentioned in the above embodiment are examples and may be different numerical values.

[Brief description of drawings]

FIG. 1 Schematic of waste treatment plant

[Explanation of symbols]

6 Exhaust gas treatment section 12 Pyrolysis reactor 13 Combustion melting furnace 17 Bug Filter 30 activation means 31 Activated carbon residue supply means 35 Activator

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B01J 20/20 F23G 5/027 Z 4D004 20/30 5/16 Z 4G066 B09B 5/00 5/44 Z F23G 5/00 115 B09B 3/00 ZAB 5/027 303Z 5/16 5/00 Z 5/44 B01D 53/34 134E F23J 15/02 F23J 15/00 CF Term (reference) 3K061 AA24 AB02 AB03 AC01 BA05 CA07 DA02 DA12 DA18 DA19 FA02 FA09 FA17 FA21 FA28 3K065 AA24 AB02 AB03 AC01 BA05 HA03 3K070 DA05 DA06 DA13 DA32 DA76 3K078 AA05 BA08 BA26 BA27 CA02 CA17 CA21 CA24 4D002 AA02 AA19 AA21 AC41 BA12 DA41 A41 A41 DA41 DA41 DA41 DA02 DA05 DA05 DA05 DA05 DA05 DA06 AA46 CA04 CA09 CA24 CA28 CA29 CB04 CB13 CB42 CB45 CB47 4G066 AA04B AA43D CA33 DA02 FA18 GA25

Claims (2)

[Claims] 1. A combustion melting system in which a thermal decomposition reactor for thermally decomposing waste into thermal decomposition residue and thermal decomposition gas is provided, and the thermal decomposition gas and carbon residue selected from the thermal decomposition residue are received and burned. A waste treatment plant in which a furnace is provided and an exhaust gas treatment unit that treats exhaust gas with a bag filter is provided, and some of the carbon residues are left behind without being directed to the combustion melting furnace side. And an activation means for activating in the activator by the carbon dioxide gas supplied to the activator, and an activated carbon residue supply means for supplying the activated carbon residue to the bag filter, and carbon dioxide in the activator. When supplying the gas, the exhaust gas discharged from the activator is recovered, and carbon dioxide is generated by supplying oxygen to the recovered exhaust gas, and the carbon dioxide gas is supplied back to the activator. Waste treatment plant that is configured to so that. 2. The waste treatment plant according to claim 1, further comprising a neutralization processing unit for neutralizing the recovered exhaust gas.