JPH11148622A - Waste thermal decombustion gassifying/melting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To take out thermally decomposed gas produced in an external heat kiln furnace as high calory gas with low hydrogen chloride concentration so as to obtain a higher evaluation for usage. SOLUTION: A ventilating dryer 18 is provided on an upstream side of an external heat kiln furnace 1 for previously drying waste 6. A lime powder charge line 20 for charging lime powder is provided on the ventilating dryer 18. A recovery line 25 for thermally decomposed gas 6a is connected in a hot gas producing furnace 9 for feeding high temperature gas 10 to the external heat kiln furnace 1. Hydrogen chloride produced by drying the waste 6 with the ventilating dryer is solidified with a reaction with the lime powder, and is removed to the outside of the system. The waste 6 after dried is thermally decomposed in the external heat kiln furnace 1, and the thermally decomposed gas 6a is fed to a hot gas producing furnace 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waste pyrolysis gasification and melting apparatus for pyrolyzing waste such as municipal waste and melting a pyrolysis residue.

[0002]

2. Description of the Related Art As a current waste disposal system, a combustion system in which waste is burned in an incinerator is employed.

[0003] However, in the case of the above-mentioned combustion system,
There is a problem of dioxin generation in the flue gas, the amount of gas is large, the efficiency of using heat energy is inefficient, the ash is generated in large quantities, the treatment is difficult, and the capacity of landfills is approaching its limit. Issues have been raised.

Therefore, as a next-generation waste treatment method, waste is heated and pyrolyzed in an inert atmosphere, and the generated pyrolysis gas and pyrolysis residue (char) are melted at an air ratio of 1.3 in a melting furnace. A gasification and melting system has been developed in which ash in waste is taken out as molten slag by burning at a high temperature with a small amount of air, and demonstration operation has been performed in some of them. In such a method, an external heat kiln is used to thermally decompose the waste into gas, and the waste is indirectly heated and dried by heat from the outside to be thermally decomposed.

As shown in FIG. 2, a pyrolysis gasification / melting apparatus used for pyrolysis gasification and melting of wastes has an outlet 3 at one end rather than an inlet 2 at one end.
Inlet 2 at one end in the longitudinal direction of a rotary type external heat kiln furnace 1 arranged sideways with its side inclined at about 3 degrees lower
In addition, a dust feeder 4 is provided so that waste 6 is charged from a charging hopper 5, and a pyrolysis gas 6 a and a pyrolysis residue 6 b are provided to an outlet 3 at the other end in the longitudinal direction of the external heat kiln 1. A separation chamber 7 for separating the wastewater is provided, and in a state where the external heat kiln furnace 1 is rotated at a low speed, the waste 6 charged from the charging hopper 5 is gradually supplied into the external heat kiln furnace 1 by the duster 4. While the heat recovery air 13
The hot gas (hot air) 10 generated in the hot-air generating furnace 9 using the gas and the auxiliary fuel 12 flows through the high-temperature gas supply line 11 from the outlet 3 side to the inlet 2 side, and is discharged from the combustion exhaust gas line 17. Thereby, the waste 6 in the external heat kiln 1 is heated, dried, and thermally decomposed, and the generated pyrolysis gas 6a is passed through a pyrolysis gas extraction line 14 connected to the upper part of the separation chamber 7 at the three outlets. It is sent to the downstream melting furnace 15, and on the other hand, the pyrolysis residue 6 b containing metals is recovered to the melting furnace 15 through the pyrolysis residue line 16 after recovering the metals 6 d, and further burned at a high temperature of 1300 ° C. or more. Then, the molten slag 6c is taken out. In addition,
The combustion exhaust gas 10 a of the external heat kiln 1 is circulated to the hot air generator 9 by the fan 30, and the surplus is guided to the exhaust gas outlet of the melting furnace 15.

[0006]

However, in the case of the above-mentioned pyrolysis gasification and melting apparatus, when waste containing a relatively large amount of plastics such as polyvinyl chloride is pyrolyzed, the concentration of hydrogen chloride in the pyrolysis gas 6a is reduced. If the amount of water contained in the waste 6 is large, the moisture of the pyrolysis gas 6a also increases, so that the pyrolysis gas 6a cannot be taken out as a gas having a low hydrogen chloride concentration and a high calorie. . Further, it has been difficult to use the pyrolysis gas 6a as a heat source of the external heat kiln furnace 1 because the calorific value is low and hydrogen chloride is a corrosion source.

In view of the above, the present invention enables the pyrolysis gas generated in an external heat kiln furnace to be extracted as a gas having a low hydrogen chloride concentration and a high calorie. It is intended to make it possible to use it effectively as a heat source.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a method of drying and thermally decomposing waste in an external heat kiln using a high-temperature gas generated in a hot-air generating furnace as a heat source. In a waste pyrolysis gasification and melting apparatus, which is configured to send gas and pyrolysis residue to a downstream melting furnace for processing,
On the upstream side of the external heat kiln furnace, a through-air dryer for drying waste before being supplied to the external heat kiln furnace is installed,
In addition, lime powder can be introduced into the through-air dryer, and a dust collector is installed in an exhaust line of the through-air dryer.

When lime powder is introduced into the through-air dryer through a lime powder introduction line, hydrogen chloride generated in the drying stage is fixed as an alkali metal salt, and is removed from the system by being collected by a dust collector. Also, some lime powder is sent to the external heat kiln furnace together with the refuse and HCl generated in the pyrolysis stage.
To the pyrolysis residue side. On the other hand, the waste is supplied to the external heat kiln furnace after a large amount of water is removed, so that the amount of water in the pyrolysis gas can be reduced. Therefore, the pyrolysis gas can be taken out as a gas having a low hydrogen chloride concentration and a high calorie.

[0010] In addition, the recovery line for the pyrolysis gas generated by the pyrolysis in the external heat kiln furnace is provided to the hot blast furnace, so that the hydrogen chloride concentration is low and the high-calorie pyrolysis is performed. Since the gas is led to the external heat kiln furnace through the hot air generating furnace, it can be used as a heat source of the external heat kiln furnace without causing a concern about corrosion.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. In a configuration similar to that shown in FIG. 2, a waste before being supplied to the external heat kiln furnace 1 is disposed upstream of the external heat kiln furnace 1. A ventilation dryer 18 for drying the object 6 is installed as a pretreatment device, and a flue gas line 17 of the external heat kiln furnace 1 is connected to the ventilation dryer 18 so that the external heat kiln 1
The flue gas 10a after being subjected to the thermal decomposition of the waste 6 is guided as a drying heat source for the through-air dryer 18 and slaked lime is supplied to the duster 19 (or the flue gas line 17) of the through-air dryer 18. A lime powder input line 20 for inputting lime powder such as lime powder or quick lime powder is provided to convert hydrogen chloride (Cl) generated in the drying stage of the waste 6 into an alkali metal salt (C).
aCl ₂ ), and the exhaust line 21 of the through-air dryer 18 is branched and introduced into the hot-air generating furnace 9 and the exhaust gas outlet 22 of the melting furnace 15. A dust collector 23 is installed in the dust collector 23 so that the alkali metal salt of chlorine contained in the dried exhaust gas 10b discharged from the through-air dryer 18 can be collected by the dust collector 23 and removed outside the system.

In addition, a dust collector 24 is installed in the middle of a pyrolysis gas extraction line 14 connected between the separation chamber 7 of the external heat kiln furnace 1 and the downstream melting furnace 15. The recovery line 25 is branched from the middle of the pyrolysis gas extraction line 14 located on the downstream side of the
5 is introduced into the hot air generator 9 so that the pyrolysis gas 6 a after passing through the dust collector 24 can be supplied to the hot air generator 9. In between, a return line 26 for returning the pyrolysis residue 6b collected by the dust collector 24 to the pyrolysis residue line 16 is provided.

Reference numeral 27 denotes an open / close control valve provided in the recovery line 25 so as to be opened / closed by a command from a temperature controller 28 provided in the high-temperature gas supply line 11. Reference numeral 31 denotes a fan for pyrolysis gas.

In the waste pyrolysis gasification and melting apparatus of the present invention having the above-mentioned structure, the waste 6 is heated and dried in the external heat kiln 1 before being thermally decomposed. It is dried to remove about 50% of water, and the dried waste 6 is supplied to the external heat kiln furnace 1.

In the above case, when the operation is performed such that the high-temperature gas 10 generated in the hot-air generating furnace 9 is passed through the high-temperature gas supply line 11 to the heating flow path 8 of the external heat kiln furnace 1, During the combustion, the combustion exhaust gas 10 a after being subjected to the thermal decomposition of the waste 6 in the external heat kiln furnace 1 is supplied to the ventilation dryer 18 through the combustion exhaust gas line 17 as a heat source of the ventilation dryer 18.

In the through-air dryer 18, the waste 6 is dried by direct contact heating with the supplied combustion exhaust gas 10 a. At this time, the lime powder passes through the lime-powder input line 20 in the through-air dryer 18. Since it is in the charged state, hydrogen chloride (C) generated from the waste 6 in the drying stage
l) is converted into a solid of an alkali metal salt (CaCl ₂ ) by the reaction, and the solid of the alkali metal salt is collected by a dust collector 23 through an exhaust line 21, so that the solid can be removed outside the system. it can.

On the other hand, the waste 6 dried by the through-air drier 18 is then supplied to the external heat kiln furnace 1, and in the external heat kiln 1, much water has been removed. Since the waste 6 is thermally decomposed, the amount of water in the pyrolysis gas 6a is also reduced, and a high-calorie gas can be taken out. At this time, even in the external heat kiln furnace 1, some hydrogen chloride is generated in the pyrolysis stage, but unreacted lime powder is also supplied from the through-air dryer 18. 6b side. Therefore, the high-calorie pyrolysis gas 6a having the minimum hydrogen chloride concentration can be taken out.

Further, the pyrolysis gas 6a is supplied from the pyrolysis gas extraction line 14 through the recovery line 25 to the hot air generating furnace 9.
Therefore, the pyrolysis gas 6a can be effectively used as a heat source of the external heat kiln furnace 1 without fear of corrosion.

Although the dried exhaust gas 10b after drying the waste 6 by the through-air dryer 18 contains an odorous component, it is led to the exhaust gas outlet 22 of the melting furnace 15 through the exhaust line 21. Here, by being mixed into the molten exhaust gas 29 having a high temperature of 1300 ° C. or more, it is decomposed and discharged at a high temperature.

[0021]

As described above, according to the present invention, the following excellent effects are exhibited. (1) The waste in the external heat kiln furnace is dried and pyrolyzed using the high-temperature gas generated in the hot air generator as the heat source, and the pyrolysis gas and pyrolysis residue are sent to the downstream melting furnace for processing. In a waste pyrolysis gasification / melting apparatus, a ventilation dryer for drying waste before being supplied to the external heat kiln furnace is installed upstream of the external heat kiln furnace, and the ventilation dryer is Lime powder can be fed into the air dryer, and a dust collector is installed in the exhaust line of the above-mentioned through-air dryer. Fixed as salt,
It can be collected by a dust collector and removed outside the system, while
The waste from which much water has been removed is pyrolyzed in an external heat kiln furnace, which reduces the amount of moisture in the pyrolysis gas. By being supplied to the furnace, the hydrogen chloride generated in the pyrolysis stage can be fixed to the pyrolysis residue side, and therefore, the hydrogen chloride gas concentration is low and a high calorie pyrolysis gas can be taken out. The utility value of the pyrolysis gas can be increased. (2) By adopting a configuration in which a recovery line for pyrolysis gas generated by pyrolysis in an external heat kiln furnace is introduced to a hot air generation furnace, a low hydrogen chloride concentration and high calorie pyrolysis gas can be obtained. Since the gas can be led to the hot-air generating furnace, the pyrolysis gas can be effectively used as a heat source of the externally-heated kiln furnace without causing a fear of corrosion.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing one embodiment of a waste pyrolysis gasification and melting apparatus of the present invention.

FIG. 2 is a schematic diagram illustrating an example of a waste pyrolysis gasification and melting apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 External heat kiln furnace 6 Waste 6a Pyrolysis gas 6b Pyrolysis residue 6c Melt slag 8 Heating path 9 Hot air generator 10 High temperature gas 10a Combustion exhaust gas 18 Ventilation dryer 20 Lime powder input line 21 Exhaust line 23 Dust collector 25 Collection line

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁶ Identification code FI F23G 5/20 ZAB F23G 5/20 ZABA F23J 1/00 F23J 1/00 B (72) Inventor Munetaka Hagiya Toyosu, Koto-ku, Tokyo 3-1-1-15 Ishikawajima Harima Heavy Industries, Ltd.

Claims (2)

[Claims] 1. A method of drying and thermally decomposing waste in an external heat kiln furnace using a high-temperature gas generated in a hot air generating furnace as a heat source, and sending a pyrolysis gas and a pyrolysis residue to a downstream melting furnace for processing. In the waste pyrolysis gasification and melting equipment that has been
On the upstream side of the external heat kiln furnace, a through-air dryer for drying waste before being supplied to the external heat kiln furnace is installed,
A waste pyrolysis gasification / melting apparatus characterized in that lime powder can be introduced into the through-air dryer and a dust collector is installed in an exhaust line of the through-air dryer. 2. The waste pyrolysis gasification and melting apparatus according to claim 1, wherein a recovery line for the pyrolysis gas generated by the pyrolysis in the external heat kiln furnace is installed in the hot air generation furnace.