JP3074617B2 - Superheated steam generation method and device by refuse incineration - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for generating superheated steam by incinerating refuse containing chlorine compounds. More specifically, the present invention relates to a method for incompletely burning refuse without using a desalinating agent to remove a part of the refuse. Along with the char, the chlorine contained in the ash contained in the char is fixed, and the char is burned to generate a combustion gas having an extremely low HCl concentration.
The present invention relates to a method and an apparatus for generating superheated steam with this gas. Since the char does not contain moisture,
If the char is burned at a low temperature, the combustion gas contains almost no HCl.

[0002]

2. Description of the Related Art When refuse is burned with excess air, Cl in chlorine compounds such as vinyl chloride and salt in the refuse reacts with H in moisture to form HCl gas, which is contained in the exhaust gas. Therefore, there is a problem that the HCl gas corrodes a heat exchanger and the like. For this reason, conventionally, refuse is burned at a low temperature of 450 to 550 ° C.
A method is known in which O, CaCO ₃ , Ca (OH) ₂ , Na ₂ CO _3, etc. are added to cause a reaction such as CaO + 2HCl → CaCl ₂ + H ₂ O to remove HCl as CaCl ₂ from the combustion gas ( For example, JP-A-6-2
01114). In the conventional method, 1500pp
The refuse which discharges the exhaust gas containing HCl of m 2 is burned in a fluidized bed, and CaO or the like is charged into the refuse to desalinate to about 100 ppm at 550 ° C.

[0003]

As described above, in the conventional method, CaO, CaCO ₃ , Ca (O
H) ₂ , Na ₂ CO _3, etc. are required, so maintenance costs are incurred. Further, there is a problem that low-temperature combustion is inevitable in order to cause a reaction, and combustion efficiency is low. The present inventor, in order to solve the above problems, as a result of repeated experiments and research, as a result of incomplete combustion (lack of air or low-temperature combustion) of the garbage, when some of the garbage is char, This char also contains chlorine, but since there is no moisture, it was found that when the char was burned at a low temperature, HCl was hardly contained in the combustion gas. In addition, when air is injected only in a required air amount or less (air ratio is 1 or less) and a gasification reaction (partial combustion, reduction combustion) of the garbage is caused, Cl in the garbage is not converted into HCl, and NaCl, KCl , CaCl _2, etc., and remained in the ash.

[0004] The present invention has been made based on the above findings, and an object of the present invention is to partially burn refuse into char containing chlorine and burn the char by burning the refuse incompletely. To generate high-temperature steam without causing corrosion of the heat exchanger.

[0005]

In order to achieve the above object, a method for generating superheated steam by incineration of refuse according to the present invention comprises the steps of incompletely burning refuse containing chlorine compounds in a refuse incinerator to reduce waste. Part of the char and included in the char
The chlorine content is fixed to the ash and the hydrogen chloride concentration is low.
Give no combustible gas, a low temperature the char in the char combustion furnace
In by burning of generating less combustion gas having hydrogen chloride concentration
The combustion gas is configured to generate superheated steam. The incomplete combustion is partially burned in an air ratio of 0.25 to 0.95, preferably 0.5 to 0.7 or / and 500 to 750 ° C, preferably 550 to 700 ° C.
By performing low temperature combustion in the range of When the air ratio is less than the above range, there is a disadvantage that the gasification reaction is insufficient and the temperature of the fluidized bed is lowered. There is an inconvenience that the heat amount is not more than a large amount. When the incomplete combustion temperature is lower than the above range, char formation is insufficient, and there is a disadvantage that the char contains hydrogen. On the other hand, when the temperature exceeds the above range, carbon crystallization (graphite) of the char may occur. Has the disadvantage of becoming flame-retardant char.

The waste incineration and char combustion may be carried out in a rotary kiln furnace or stoker furnace, but more preferably in a fluidized bed furnace. In addition, the method of controlling the temperature of the fluidized bed of the refuse incinerator to 500 to 750 ° C., preferably 550 to 700 ° C. reduces the air ratio, puts a heat transfer tube in the fluidized bed, A method of injecting water and cooling is adopted. If the fluidized bed is not cooled,
It is not preferable because the temperature of the fluidized bed rises to 750 ° C. or more.

[0007] A superheated steam generator for incineration of waste according to the present invention comprises a fluidized bed incinerator for incompletely burning waste containing chlorine compounds, and an incompletely combusted material extracted from the fluidized bed of the incinerator for large incombustibility. objects and the chlorine content in the ash immobilized <br/> char and secondary classification to classifier, chlorine is immobilized in the ash by introducing a combustible gas containing char from the incinerators
A dust separator which is char and separating the less inflammable gases hydrogen chloride concentration, low hydrogen chloride concentration char from the dust separator and the classifier is burned at a low temperature
A fluidized bed char combustion furnace Ru to generate combustion gases have a superheated steam generation tube provided in the fluidized bed of the char combustion furnace,
It is characterized by consisting of. In the above device,
Instead of providing the superheated steam generation tube in the fluidized bed of the char combustion furnace, it is also possible to provide it on a free board of the char combustion furnace.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an example of an apparatus for carrying out a method for generating superheated steam by incineration of waste according to the present invention. This example shows a case where a fluidized bed furnace is used as the refuse incinerator 10 and the char combustion furnace 12. The fluidized bed 14 is made of ash and silica sand as a fluidized medium, and refuse is injected into the fluidized bed 14 and incompletely burned. 16 is a garbage hopper. An air ratio of 0.25 to 0.95, preferably 0.5
The air in the range of ~ 0.7 is supplied and dispersed and ejected into the fluidized bed 14 through the air dispersion plate 20 to fluidize the fluidized medium, and a heat transfer tube is provided in the fluidized bed to recover heat, or By pouring water into the fluidized bed, the temperature of the fluidized bed is controlled in the range of 500 to 750 ° C, preferably 550 to 700 ° C. Alkali metal oxides such as Na ₂ O and K ₂ O in ash and alkaline earth metal oxides such as CaO react with Cl in garbage to be fixed as chlorides such as NaCl, KCl and CaCl ₂ . The HCl contained in the char is greatly reduced in the combustible gas. This combustible gas contains dust (char) containing Cl and a small amount of HCl.
Will be contained.

The char containing ash having Cl immobilized thereon is extracted from the fluidized bed 14 together with the large incombustible material, and the large incombustible material and the ash having Cl immobilized thereon are separated by a classifier 22 such as a vibrating sieve. The char is divided into the char and the char combustion furnace 12 by the air from the blower 26 through the char hopper 24.
Is transported by airflow to the fluidized bed 28 and burned. Reference numeral 30 denotes a discharger, 32 denotes a wind box, and 34 denotes an air distribution plate. The combustible gas from the fluidized bed 14 of the refuse incinerator 10 is supplied to a free board 36.
, And is introduced into a dust separator 38 such as a cyclone, where char containing ash containing about 10% Cl and combustible gas are separated. Combustible gas includes CO, H
₂ etc. are included. Combustible gases further include CH ₃ and C
₂ H _{6 and the} like may be included. This flammable gas is
Since the HCl concentration is extremely low, it is burned in another combustion furnace or combustor (not shown) and then sent to a boiler or turbine (not shown) to recover heat or power.

The dust (char) containing ash containing Cl separated in the dust separator 38 is supplied to the fluidized bed 28 of the char combustion furnace 12 and burned. A superheated steam generating tube 40 is provided in the fluidized bed 28, for example, 4
It is configured such that steam of about 50 ° C. is supplied to generate high-temperature superheated steam of about 600 ° C. The temperature of the fluidized bed 28 is around 800 ° C. The char supplied to the fluidized bed 28 contains chlorine, but does not contain moisture, and when burned at a low temperature, CaCl ₂ + H ₂ O
→ No reaction such as 2HCl + CaO occurs and HCl is hardly contained in the combustion gas. This combustion gas passes through the free board 42 and is introduced into a dust separator 44 such as a cyclone to remove dust, and then discharged outside the system.

In FIG. 1, the case where the superheated steam generation pipe is provided in the fluidized bed has been described. However, as shown in FIG. 2, the superheated steam generation pipe 40a can be provided in the free board 42.

[0012]

【Example】

Example 1 Using the apparatus shown in FIG. 1, refuse containing 10 wt% of Cl was incinerated. The refuse is treated in the fluidized bed 14 of the refuse incinerator 10 with an air ratio λ = 0.6, a fluidized bed 14 temperature of 700 ° C.
A heat transfer tube was provided inside the heat transfer tube and water was passed through the heat transfer tube.)
0 kcal / kg of dust (char) was collected in cyclone 38. This char was burned at 700 ° C. in the fluidized bed 28 of the char combustion furnace 12 to convert 450 ° C. steam into 600 ° C. superheated steam. The HCl concentration in the combustion gas was 20 ppm. The HCl concentration in the combustible gas (740 ° C.) from the cyclone at the waste incinerator outlet is 20%.
ppm.

[0013]

As described above, the present invention has the following effects. (1) Without using a desalinating agent, incomplete combustion of garbage to make a part of the garbage into char, fix the chlorine content in ash contained in this char, burn this char, and burn HCl Generates very little combustion gas,
Since the heat transfer tube is heated by this combustion gas to generate superheated steam, corrosion of the heat transfer tube such as the superheated steam generation tube can be significantly reduced. (2) It is possible to obtain flammable gas containing only a very small amount of HCl at the same time as incompletely burning garbage without using a desalinating agent. This flammable gas is burned again and used for boilers and turbines. By feeding gas, heat recovery or power recovery can be performed while suppressing corrosion of the boiler or turbine.

[Brief description of the drawings]

FIG. 1 is a system diagram showing an example of an apparatus for implementing a method for generating superheated steam by incineration of waste according to the present invention.

FIG. 2 is a system diagram showing another example of an apparatus for performing the method of the present invention.

[Explanation of symbols]

 Reference Signs List 10 refuse incinerator 12 char combustion furnace 14 fluidized bed 16 refuse hopper 18 wind box 20 air dispersion plate 22 classifier 24 char hopper 26 blower 28 fluidized bed 30 discharger 32 wind box 34 air dispersion plate 36 free board 38 dust separator 40 Superheated steam generation pipe 40a Superheated steam generation pipe 42 Free board 44 Dust separator

────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FIF23G 5/14 ZAB B09B 3/00 ZAB F27B 15/00 303F (56) References JP-A-5-93513 (JP, A) JP-A-6-265121 (JP, A) JP-A-7-71735 (JP, A) JP-A-7-35322 (JP, A) JP-A-60-148830 (JP, U) (58) Int.Cl. ⁷ , DB name) F23G 7/00 B09B 3/00 F23G 5/027 F23G 5/14 F27B 15/00 F23G 5/30 F23C 11/02

Claims (5)

(57) [Claims] Claims: 1. Incomplete combustion of waste containing chlorine compounds in a waste incinerator to turn part of the waste into char
While immobilizing chlorine in the ash contained in the char,
A flammable gas having a low hydrogen chloride concentration is obtained, and the char is burned at a low temperature in a char combustion furnace to produce a fuel having a low hydrogen chloride concentration.
A method for generating superheated steam by incineration of refuse, comprising generating a combustion gas and generating superheated steam with the combustion gas . 2. The method according to claim 1, wherein the incomplete combustion is performed at an air ratio of 0.25 to 0.9.
Partial combustion in the range of 5 or / and 500-75
The method for generating superheated steam by incineration of refuse according to claim 1, wherein the method is carried out by burning at a low temperature within a range of 0 ° C. 3. The method for generating superheated steam by incineration of refuse according to claim 1, wherein refuse incineration and char combustion are performed in a fluidized bed. 4. A fluidized bed refuse incinerator for incompletely burning refuse containing chlorine compounds, and an incompletely burned substance is extracted from the fluidized bed of the refuse incinerator to fix chlorine in large incombustibles and ash. A classifier that classifies the char and the char whose chlorine content is fixed in the ash by introducing flammable gas containing char from the refuse incinerator and the hydrogen chloride concentration
A dust separator for separating a less flammable gases, the dust separator and fluidized bed char combustion furnace to the char from the classifier by <br/> burned at low temperatures Ru generates less combustion gas having a hydrogen chloride concentration And a superheated steam generation pipe provided in a fluidized bed of the char combustion furnace. 5. The superheated steam generator according to claim 4, wherein the superheated steam generation pipe is provided on a free board of the char combustion furnace instead of being provided in the fluidized bed of the char combustion furnace.