JPS58156107A - Fluidized bed type combustion furnace - Google Patents

Abstract

PURPOSE:To reduce the production of NOX, by forming a single-stage combustion chamber, in which an object to be incinerated is burnt by fluidized gas having a low air ratio to produce a reducing atmosphere, and a two-stage combustion chamber for performing a perfect combustion of an unburning content contained in the reducing atmosphere. CONSTITUTION:An object 14 to be incinerated charged into a single-stage combustion chamber 9 through a charging inlet 15 for object to be incinerated is burnt over fluidization. An air ratio of fluidized gas 12 is set to a lower value compared with the quantity of the object 14 to be incinerated, whereby a combustion temperature is prevented from rising to high temperature, and a quantity of NOX produced can be suppressed. Additionally, an air amount is insufficient, and as a result, gas, such as carbon monoxide, having a reducing property, is produced. The reducing atmosphere decreases the reduced NOX to produce nitrogen gas, and thereby the quantity of NOX produced can be decreased. Reduced gas containing an unburning content such as carbon monoxide is intruduced in a two-stage combustion chamber 10 to perfectly burn it in an oxidizing atmosphere.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fluidized bed incinerator that incinerates materials to be incinerated such as industrial waste while fluidizing them with a fluidizing gas, and particularly relates to a fluidized bed incinerator that incinerates materials to be incinerated such as industrial waste, and in particular nitrogen oxides (hereinafter abbreviated as r, NOxJ). The present invention relates to a fluidized bed incinerator that can reduce the amount of waste generated as much as possible. - Generally, a fluidized bed incinerator is known as a device for incinerating materials to be incinerated such as municipal waste and industrial waste.

To explain the specific VC of this conventional fluidized bed incinerator based on the attached drawings, first, as shown in FIG. The 3 t of materials to be incinerated are incinerated while being fluidized by the fluidizing gas injected from the aeration pipe 4 together with the sand as a fluidizing medium.

The residue generated after the incineration process continues to flow down and is discharged outside the furnace from the residue discharge port 5 provided at the bottom of the incinerator, while the generated exhaust gas 6 is discharged from the exhaust gas discharge lower provided at the top of the incinerator. It is being ejected from the furnace. Since this exhaust gas 6 contains NOx generated by the incineration process, depending on the regulation value, it may be necessary to remove NOx with a denitrification device (not shown) and then discharge it to the outside of the system as clean gas. There is.

By the way, this type of incinerator does not take any measures to reduce NOx, so it generates a considerable amount of NOx, which is a harmful gas, and therefore the amount of NOx, which is a harmful gas, from the exhaust gas is below the regulation value. In order to remove the nitrogen, a large-sized denitrification device (not shown) had to be installed separately, which forced an increase in equipment costs.

The present invention was devised to effectively solve the above-mentioned problems, and its purpose is to solve the problems described above.
a single-stage combustion chamber that generates a reducing atmosphere by burning the incinerated material with a fluidizing gas having a low air ratio to suppress the amount of Ox;
A two-stage combustion chamber is formed to completely burn the unburned substances contained in this reducing atmosphere, thereby reducing NOx, which is a harmful gas.
The object of the present invention is to provide a fluidized bed incinerator that can reduce the generation of 1tt as much as possible.

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

First, as shown in FIG. 2, the fluidized bed incinerator 8 generates N.
In order to suppress the amount of Ox, a fluidizing gas vc↓ with a low air ratio is used to burn the material to be incinerated to generate a reducing atmosphere. A round two-stage combustion chamber 10 that completely burns the unburned content
It is mainly composed of.

Specifically, in the lower part of the first-stage combustion chamber 9, a hook is provided between the side walls of the casing 11a that partitions the chamber, and a hook is provided at a predetermined interval from each other for injecting the fluidizing gas 12 into the combustion chamber. A plurality of air diffusers 13... are formed. A to-be-incinerated material inlet 15 is formed on the side wall of the casing above these diffuser pipes 13 for injecting 14 tons of incinerated materials such as industrial waste into the combustion chamber 9. The material to be incinerated 14 can be incinerated while being fluidized by fluidizing gas 12 as primary air injected from the aeration pipe 13. In particular, the fluidizing gas 12 supplied at this time is set so that its air ratio is 1 or less compared to the amount of the material to be incinerated, thereby suppressing the generated NOx 'Ik't-. At the same time, the atmosphere within the combustion chamber can be made into a reducing atmosphere of carbon monoxide (CO) or the like.

An exhaust gas port 16 is formed in the upper side wall of the casing l1m to introduce the exhaust gas or 1f light atmosphere in the first stage combustion chamber 9 into the second stage combustion chamber 10. The combustion chamber 9 is connected to a two-stage combustion chamber 10. This two-stage combustion chamber 10 is vertically elongated with the exhaust gas port 16 located approximately in the center.

The side wall of the casing llb that partitions this combustion chamber 10 is filled with air (
2 for introducing secondary air) 17 into the two-stage combustion chamber 10.
A secondary air supply pipe 18 is provided to completely burn the unburned content contained in the reducing atmosphere and create an oxidizing atmosphere therein. A narrow gas cooling water introduction pipe 19 is provided at the top to reduce the temperature of the exhaust gas and remove soot from the exhaust gas (oxidizing atmosphere). The temperature of the exhaust gas after the fuel is completely combusted is lowered, and the soot and dust contained therein can be removed by adhering to the cooling water 20.

Furthermore, an exhaust gas discharge port 21 is provided on the upper side wall of the casing 11b for discharging purified exhaust gas from which soot and dust has been removed to the outside of the furnace.
A soot and dust outlet 22 is provided at the lower end for discharging all the soot and dust removed from the cooling water 20 to the outside of the furnace.
The cooling water 20 is configured so as not to flow into the first-stage combustion chamber.

In addition, a secondary air supply pipe 1am* is also provided on the upper side wall of the casing 11m that partitions the first-stage combustion chamber 9, so that the amount of carbon monoxide etc. generated in the reducing atmosphere formed here can be increased or decreased as appropriate. The operation of the present invention configured as described above will be explained in detail.

First, the material to be incinerated 14 such as industrial waste thrown into the first-stage combustion chamber 9 from the material to be incinerated input port 15 is mixed with a fluid medium such as sand as primary air injected from the aeration pipe 13. , and are fluidized by the unit 12 and incinerated. At this time, the air ratio of the fluidizing gas 12 is set to be lower than 1 compared to the amount of the incinerated material 14, so that the combustion temperature does not become high and the amount of NOx generated is suppressed. Also, due to the lack of air, reducing gases such as carbon monoxide are generated,
A reducing atmosphere is formed within this single-stage combustion chamber 9. In addition, this reducing atmosphere reduces NOx generated and generates nitrogen gas (N2).
The occurrence of x can be reduced as much as possible.

Here, residues such as incombustible materials generated by the incineration process flow down inside the furnace and are discharged from the furnace through a residue discharge port 23 provided at the bottom.

On the other hand, after the NOx reduction treatment, the reducing atmosphere (I gas) containing carbon monoxide, etc. remaining as unburned matter is then
6 into the two-stage combustion chamber 10. An oxidizing atmosphere is formed in this two-stage combustion chamber 10 because a large amount of secondary air 11 is supplied through secondary air supply pipes 18 to compensate for the lack of air amount. Therefore, unburned carbon monoxide and the like in the reducing atmosphere are completely combusted in the oxidizing atmosphere, producing harmless carbon dioxide.

The exhaust gas whose unburned content has been completely combusted in this way is further cooled sufficiently by the gas cooling water 20 sprayed through the gas cooling water introduction pipe 19 provided at the upper part of the two-stage combustion chamber 10, and then the exhaust gas is It will be discharged from the furnace through the discharge port 21.

In addition, this gas cooling water 20 adsorbs and removes soot in the exhaust gas, creating a single-stage combustion chamber! The air flows down inside the second-stage combustion chamber 10 without flowing into the second-stage combustion chamber 10, and is then discharged to the outside of the furnace from the dust outlet 22 provided at the bottom.◎ As described above, air in the first-stage combustion chamber 9 By incinerating 14 tons of incinerated materials while keeping the ratio low and creating a reducing atmosphere, the combustion temperature is low and the NOx generated is reduced.
Jli f can be reduced, and the NOx generated can be reduced to nitrogen gas in a reducing atmosphere, so the overall amount of NOx generated can be reduced as much as possible.
, 轡a.

Moreover, since the unburned matter produced in the first stage combustion chamber 9 is completely combusted by the secondary air 11 supplied in the second stage combustion chamber 10, the unburned matter is not discharged outside the furnace.

In short, according to the present invention, the following excellent effects can be achieved.

(1) Since the amount of nitrogen oxides (NOx), which is a harmful gas, generated can be reduced as much as possible, the denitrification equipment that was previously required can be eliminated, resulting in a significant reduction in equipment costs. It is possible to aim for

(2) Since the gas cooling water sprayed in the two-stage combustion chamber adsorbs and removes soot and dust, the dust collector can be downsized or made unnecessary.

(3) Since the second-stage combustion chamber provided with the lf gas cooling water inlet pipe is separated from the first-stage combustion chamber, there is no risk of water being sprayed directly into the fluidized bed even if this inlet pipe breaks down.

(4) Since the combustion temperature in the single-stage combustion chamber is lowered, the height of this combustion chamber can be lowered, which allows equipment such as a dust collector to be installed above the combustion chamber.
Convenient layout is possible.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing a conventional fluidized bed incinerator, and FIG. 2 is a longitudinal sectional view showing a fluidized bed incinerator according to a preferred embodiment of the present invention. In addition, 8 out of 1 is a fluidized bed incinerator, 9 is a single-stage combustion chamber, 10 is a two-stage combustion chamber, 12 is a fluidizing gas (primary air), 13 is a diffuser pipe, 14 is a material to be incinerated, and 15 is a combustion chamber. Incineration material input port, 17 is secondary air, 20 is gas cooling water, 21 is exhaust gas outlet, 2
2 is a dust outlet, and 23 is a residue outlet. Patent applicant: Ishikawajima-Harima Heavy Industries Co., Ltd. Agent Patent attorney: Nobuo Kinutani

Claims (1)

[Claims] In a fluidized bed incinerator that incinerates the material to be incinerated while fluidizing it with a fluidizing gas, a single-stage combustion chamber that generates a reducing atmosphere by burning the material to be incinerated while fluidizing it with a fluidizing gas having a low air ratio; It is characterized by comprising a second stage combustion chamber which supplies secondary air to the first stage combustion chamber to generate an oxidizing atmosphere in order to completely burn all the unburned substances contained in the reducing atmosphere generated in the first stage combustion chamber. Fluidized bed incinerator.