JPH0989227A - Waste pyrolysis melting system - Google Patents

Abstract

(57) [Summary] [Purpose] To provide an economically efficient waste pyrolysis / melting system by effectively utilizing the energy originally possessed by waste itself. [Structure] A waste heat boiler 2b for burning gas generated in a thermal decomposition furnace 5 to recover steam, and steam 1 generated in the waste heat boiler 2b.
1 further burns the residue 3 of the thermal decomposition furnace 5 in the melting furnace 1 at high temperature,
In order to overheat the exhaust gas 7, a super heater 2a is provided and configured.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a thermal decomposition furnace and a melting furnace for waste, a waste heat boiler for generating steam from combustion heat of gas generated in the thermal decomposition furnace, and a waste heat boiler. The present invention relates to a waste pyrolysis / melting system including a power generator that generates electric power after superheating steam with exhaust gas from a melting furnace.

[0002]

2. Description of the Related Art In recent years, attention has been paid to a garbage power generation system for effectively generating heat by using heat generated in an incinerator for municipal waste, but a heat transfer tube using sulfides or chlorides contained in exhaust gas from the incinerator. In order to prevent high temperature corrosion of heat exchange parts such as
The steam generated by the waste heat boiler could not be superheated to a high temperature of 300 ° C or higher. Therefore, conventionally, in order to raise the steam temperature and improve the power generation efficiency, a combustion type superheater using city gas or propane gas as a supply fuel is provided outside the refuse incinerator, and the combustion type superheater is used to The steam generated in the waste heat boiler was superheated to about 500 ° C or higher under high pressure.

On the other hand, semi-fluid organic matter such as sewage sludge is dehydrated by a dehydrator or dried by a gas stream dryer utilizing the waste heat of an incinerator, and then directly used in a rotary kiln or a fluidized bed type incinerator. Since it was thrown in and incinerated, the same inconvenience occurred even if the waste heat boiler was installed in the incinerator, and it was necessary to install the combustion type superheater outside the refuse incinerator.

[0004]

However, in the conventional refuse power generation system, it is necessary to install a separate combustion type superheater in addition to the waste heat boiler, and to use new fossil fuel, which is a point of saving energy resources. Therefore, it was required to generate electricity with high efficiency by effectively utilizing the waste itself.

An object of the present invention is to provide a waste pyrolysis / melting system which is highly economical and stable by effectively utilizing the energy originally possessed by the waste itself.

[0006]

In order to achieve this object, the characteristic constitution of the waste pyrolysis / melting system according to the present invention is as follows.
A thermal cracking furnace and a waste heat boiler that combusts the gas generated in the thermal cracking furnace to generate steam, and a melting furnace that melts the residue of the thermal cracking furnace, and melts the steam generated in the waste heat boiler. The point is that a super heater is provided that overheats the high-temperature exhaust gas of the furnace.

[0007]

In other words, organic substances contained in sludge, municipal waste, etc. are essentially hydrocarbons as main components, and these are put into a pyrolysis furnace using, for example, a rotary kiln or a fluidized bed furnace, When decomposed at a temperature of 600 ° C. to 800 ° C., combustible gases such as carbon monoxide and hydrogen are produced together with acidic gases such as sulfides and chlorides and gaseous tar.

On the other hand, the residue decomposed in the thermal decomposition furnace does not contain chlorine or sulfur which is a source of harmful gas. Its main components are char and carbon. Therefore, when the residue of the thermal decomposition furnace is incinerated and melted by the melting furnace, it becomes a clean high temperature exhaust gas and the problem of high temperature corrosion is solved, and the superheater using the exhaust gas as a heat source superheats the steam.

Moreover, in the secondary combustion chamber, the generated gas is incinerated, but the gaseous tar contained in the combustible gas is also incinerated at the same time. Therefore, tar and organic acid generated as a result of purification by the exhaust gas treatment device are The troublesome treatment of dissolved wastewater does not occur.

[0010]

As described above, according to the present invention, it is possible to effectively utilize the energy originally possessed by the waste itself, and to provide a waste power generation system having a high economic efficiency.

[0011]

EXAMPLES Examples will be described below. As shown in FIG. 1, the waste pyrolysis / melting system includes a pyrolysis furnace 5 that pyrolyzes sludge, municipal waste, etc. to produce a flammable gas, and a flammable gas produced in the pyrolysis furnace 5. A secondary combustion chamber with a waste heat boiler 2b that burns and recovers energy as steam, a melting furnace 1 that combusts and melts the residue of the pyrolysis furnace 5, and an exhaust gas 7 generated in the furnace 1 installed after the melting furnace 1. 2 that superheats the steam of the waste heat boiler 2b from the heat retained by the
a and a power generation device 4 for generating power by the steam 11 generated in the waste heat boiler 2b.

The thermal decomposition furnace 5 heats organic waste such as municipal waste and sewage sludge at a high temperature of about 600 ° C. to 800 ° C. under the restriction of the air supply amount to generate combustible gas. A fluidized bed furnace or a rotary kiln furnace as shown in FIGS. 2 and 3 is used. As shown in FIG. 2, the fluidized bed furnace has a structure in which an air ejection nozzle 5c is provided below a combustion chamber 5a with a wind box 5b interposed therebetween, and a sand layer 5d is placed on the air ejection nozzle 5c. The sand layer floats and becomes a fluidized state to form a fluidized bed, and after heating the sand layer 5d by the starter burner 5e, waste such as sludge is supplied therein to be combusted and gasified. In the rotary kiln furnace, as shown in FIG. 3, a cylindrical furnace body 5f in an inclined posture rotates, and the incineration objects such as wastes supplied inside from the supply port 5g are sequentially stirred to form a supply port 5g. While transferring to the opposite side, it is sequentially combusted and gasified.

The exhaust gas treating apparatus 10 converts the oxidizing gas such as SOx and HCl from the exhaust gas from the secondary combustion chamber into CaSO ₄ ,
An exhaust gas treatment device 10 is provided for spraying powdered slaked lime 13 for absorption reaction from the flue 9 in order to remove it by reacting with CaCl ₂ or the like and finally removing it together with dust.

The melting furnace 1 does not have to be limited to any particular model, and may be a swirling type, a surface type, a shaft type or the like.

The residue 3 from the pyrolysis furnace is composed of carbon, sand, glass, metal, etc., and the volatile chlorine, sulfur, etc., which were present in the waste, have been scattered into the generated gas, so the above residue Since the high temperature corrosive gas of the super heater 2a is hardly present in the exhaust gas 7 obtained by high temperature combustion of 3 in the melting furnace 1, for example, the steam generated in the waste heat boiler 2 is about 100 kg / m ^{2 in the} super heater. 500 at high pressure
It can be heated above ℃.

The power generator 4 is composed of a steam turbine and a generator, and the steam supplied to the steam turbine is returned to the waste heat boiler 2b via a condenser 14 and an economizer 2c.

The method and structure of the thermal decomposition furnace are not particularly limited, and methods other than the rotary kiln method and fluidized bed method described above may be adopted, and the structure thereof is also arbitrary.

The structure and system of the melting furnace are not limited to the particular ones, and a swirling flow system, a blast furnace system and the like can be used.

The exhaust gas treating apparatus is not particularly limited and can be constructed by various known methods.

It should be noted that reference numerals are added to the claims for convenience of comparison with the drawings, but the present invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a waste pyrolysis / melting system.

FIG. 2 is a configuration diagram of a main part.

FIG. 3 is a configuration diagram of a main part

[Explanation of symbols]

 1 Melting Furnace 2a Super Heater 2b Waste Heat Boiler 4 Generator 5 Pyrolysis Furnace 10 Exhaust Gas Treatment Device

Claims (1)

[Claims] 1. A thermal decomposition furnace (5) and a waste heat boiler (2b) for combusting gas generated in the thermal decomposition furnace (5) to generate steam.
And a melting furnace (1) for melting the residue of the thermal decomposition furnace (5), and superheats the steam generated in the waste heat boiler (2b) by the high-temperature exhaust gas of the melting furnace (1). The waste thermal decomposition melting system provided with (2a).