JPH11257619A - City refuse combustion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress discharge of a chlorine compound generated by combustion of city refuse and a heavy metal. SOLUTION: This combustion device comprises a furnace 2 to perform thermal decomposition of city refuse 1, an adsorption device to adsorb a hazardous material by char 33 generated by the thermal decomposition furnace 2, an adsorbent treating device to separate the hazardous material and treat it into a non-hazardous state, and a means to supply the char 33 to a melt combustion furnace 12. The thermal decomposition char 33 is used as an adsorbent for a hazardous material, and by providing a means to bring the hazardous material into a non-hazardous state, even when city refuse is burnt, the amount of a generating hazardous material is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion apparatus capable of effectively removing dioxin and the like in flue gas from a combustion furnace for burning municipal solid waste.

[0002]

2. Description of the Related Art Municipal garbage is approximately 1 watt in terms of chlorine converted to weight.
t% included. When this chlorine burns, HCl or Cl ₂ gas is generated. These chlorine gases react with unburned carbon to generate dioxins. Dioxin has recently been reported to be a carcinogenic toxic substance, and the control of the generation of these toxic gases has been set by guidelines of the Ministry of Health and Welfare. Against this background, large-scale facilities that incinerate municipal solid waste have reduced the concentration of dioxin in the flue gas to a level of 0.1.
It is required to reduce it to 1 ng TEQ / Nm ³ or less.

[0003] Conventional refuse combustion equipment employs a method in which a bag filter is provided downstream of a refuse heat boiler, and activated carbon or slaked lime is supplied to combustion exhaust gas from upstream of the bag filter. In these methods, harmful substances are adsorbed on activated carbon or slaked lime and collected on the bag filter surface. Inventions relating to such a method are described in JP-A-9-29046, JP-A-9-108535, JP-A-5-261359 and the like. Further, as an invention in which a bag filter and a moving layer are combined, for example, there is an invention described in Japanese Patent Application Laid-Open No. 6-281128.

In the method of supplying activated carbon or slaked lime to combustion exhaust gas from upstream of a bag filter, harmful substances such as dioxin are adsorbed by slaked lime or activated carbon. For example, as described in JP-A-9-29046, a method of regenerating and repeatedly using an adsorbent or, for example, a method of melting, reducing, and solidifying as described in JP-A-5-261359 has been used. .

On the other hand, instead of using expensive activated carbon, there is a method in which garbage is pyrolyzed to generate char, and the char is blown into combustion exhaust gas to adsorb harmful substances. Typical examples of these inventions include the invention described in JP-A-9-53815.

[0006] One of the methods for incinerating municipal solid waste is to increase the combustion efficiency compared to conventional incinerators.
Attempts have been made to reduce dioxin production by reducing unburned components. As a representative invention of this method, Japanese Patent Application Laid-Open
There are inventions described in JP-A-9-112855 and JP-A-1-49816.

[0007]

According to the method for adsorbing harmful substances, it is possible to remove harmful substances from a waste incineration plant, but this does not mean that the harmful substances generated when the adsorbent is regenerated are eliminated. Had not been completely removed. Furthermore, in this method, it is necessary to attach a regenerating device for the adsorbent to the waste incinerator, which has reduced the operability of the municipal waste combustion device.

[0008] Further, when the fly ash containing the adsorbent is reduced in volume and solidified, there is no doubt that the adsorbed harmful substances are scattered into the atmosphere again, and this may become a new pollution source.

In the method using char as an adsorbent instead of activated carbon, the treatment method for separating harmful substances from char is basically the same as the above method. For this reason,
No drastic improvement can be expected in terms of operability of waste incineration equipment and re-dispersion of harmful substances from adsorbents.

[0010] On the other hand, with respect to the combustion method for reducing unburned components by increasing the combustion efficiency, no solution has been given for the reduction of chlorine, and the diffusion of chlorine compounds into the air or the ground has been eliminated. Is impossible. For this reason, a combustion exhaust gas purifier is provided in front of the chimney. However, in this purifier as well, harmful substances may be scattered again for the above-mentioned reason.

[0011]

In order to solve the above-mentioned problems, the present invention comprises a furnace for pyrolyzing municipal waste, and an adsorption device for adsorbing harmful substances with char generated by the pyrolysis furnace. A municipal solid waste combustion device including a sorbent treatment device for separating harmful substances from char and detoxifying the char, and a means for supplying the char to a melting and burning furnace.

The char produced in the pyrolysis furnace preferably has a specific surface area of the char particles of at least 10 square meters per gram. Chars with such characteristics can reduce municipal waste.
It is produced by passing through an atmosphere having a temperature range of 400 ° C. to 500 ° C., at most 600 ° C., and an oxygen concentration of 1% or less. More specifically, it is desirable to use a kiln for the pyrolysis furnace, and the char is formed by municipal solid waste that has passed through a kiln containing combustion exhaust gas having a low oxygen concentration.

The effluent from the pyrolysis furnace contains rubble and metal in addition to char. Rubble and metal are separated from the char,
The particle size of the char is adjusted according to the form of the adsorption device. For example, when the bag filter is used as a harmful substance adsorption device, the char particle diameter is adjusted to 2 mm or less. As a method for adjusting the particle size, it is convenient to provide a cyclone on the upstream side of the bag filter and supply the char from the upstream side of the cyclone. The coarse particles in the char are collected by the cyclone, and only the fine particles passing through the cyclone can be supplied to the bag filter. Alternatively, a method may be used in which an airflow is applied to the char particles and a particle size that follows the flow velocity is selected.

[0014] A moving bed can be used in the adsorption device. In this case, it is desirable that the char particle is adjusted to 2 mm or more. More preferably, it is also possible to use a material which is sorted so as to have a uniform particle diameter, or which is obtained by compressing and solidifying a char to form a pellet having a uniform shape.

The adsorption device is installed in a region where the temperature of the combustion exhaust gas is 150 to 300 ° C. The char adsorbs harmful substances to the pores of the char. The adsorption amount of harmful substances increases almost in proportion to the specific surface area and the amount of char. The performance of adsorbing harmful substances decreases with increasing temperature under temperature conditions higher than 300 ° C. When the temperature of the flue gas falls below 150 ° C., the flue gas becomes white smoke at the smoke outlet. In order to prevent white smoke from the flue gas, it is necessary to reheat the temperature of the flue gas flowing into the chimney to 150 ° C. or higher, and the thermal efficiency of the municipal solid waste incinerator decreases.

After the harmful substances are fixed to the char and collected, they are made harmless by the adsorbent treatment device. The method of washing the char with an aqueous alkali solution is suitable for an adsorbent treatment apparatus.
As the aqueous alkaline solution, a suspension of calcium hydroxide, potassium hydroxide, magnesium hydroxide, and sodium hydroxide can be used. The method of further cleaning the adsorbent by stirring or ultrasonic waves is effective for removing harmful substances having a small molecular weight. Using this method, HCl is immobilized in the form of alkali metal chlorides and chlorine is recovered in the form of harmless solids. It is desirable that higher molecular weight substances, such as dioxin, do not dissolve in the aqueous alkaline solution and remain adsorbed on the adsorbent. The char adsorbing dioxin and heavy metals is supplied to the melting and burning furnace. As a result, among the harmful substances having a high molecular weight, combustible substances such as dioxins are decomposed at a high temperature of 1200 ° C. or more, and heavy metals are fixed to the molten slag.

As described above, the harmful substances in the combustion exhaust gas are detoxified by being adsorbed by the char and fixed in the form of chlorides, etc., and thermally decomposed or melted by returning the char to the melting combustion furnace. Included in slag. To further increase the efficiency of the above system, it is desirable that the char be washed with an alkali metal absorbing solution in the upper stage of the melting and burning furnace. As a result, the chlorine compound contained in the char is fixed by the absorbing liquid, so that the amount of the chlorine compound flowing into the melting and burning furnace can be reduced. Since chlorine is one of the sources of dioxin, dioxin generation can be reduced by reducing chlorine. At the same time, the chlorine concentration in the combustion exhaust gas is also reduced, thereby preventing the heat exchanger from chlorine corrosion. When the municipal solid waste combustion device is provided with a power generation device, the steam temperature is increased by preventing chlorine corrosion, so that the power generation efficiency is increased as compared with the conventional method.

The municipal solid waste combustion device is composed of a plurality of pyrolysis furnaces and one
When the system is composed of two melting furnaces, the operation method with excellent system operability is to manufacture the char to be supplied to the adsorption device in the first pyrolysis furnace and melt the char generated in the other pyrolysis furnace. Incineration in a combustion furnace. After starting up the first pyrolysis furnace, this system will start the second pyrolysis furnace according to the amount of waste.
The third pyrolysis furnace can be sequentially activated. The first pyrolysis furnace can supply the char to the melting and burning furnace after producing the required amount of char in the adsorption device. Furthermore, in order to operate this system stably, the state quantity of the melting and burning furnace, for example, the temperature of the flue gas at the outlet of the melting and burning furnace is detected, and the fuel is manufactured from municipal waste such as char so that the temperature is constant. It is possible to control the supply amount of the fuel or the supply amount of the auxiliary fuel supplied to the melting and burning furnace. As a result, the temperature of the portion where the molten slag is discharged is determined within the set range, so that the condition under which the molten slag easily flows can be realized regardless of the load of the molten combustion furnace.

[0019]

1 shows an embodiment of a municipal solid waste combustion apparatus. In this embodiment, a pyrolysis furnace 2 and a melting combustion furnace 1
2, a heat exchanger 16, a turbine 17, an air heater 18, a bag filter 23, a moving bed 54, and a chimney 24.

The refuse 1 is supplied to a pyrolysis furnace 2. The pyrolysis furnace 2 is adjusted to an atmosphere having a temperature of 300 to 600 ° C. and an oxygen concentration of 1% or less, and the residence time of the refuse 1 is about 1 hour. The refuse 1 is pyrolyzed in the pyrolysis furnace 2 and supplied to the separation tower 3. In the separation tower 3, the refuse 1 is separated into a pyrolysis gas 30 and a char 33. The pyrolysis gas 30 is converted into a high-temperature gas 32 in the combustor 10 using the air 31 supplied from the blower 26.
Generate The high-temperature gas 32 becomes the exhaust gas 47 after heating the pyrolysis furnace 2 and becomes the exhaust gas 4 on the upstream side of the moving bed 54.
Mix with 5.

The char 33 is sorted by the sieve 4 into a metal rubble 48 and a char 33 from which the metal rubble has been removed. Metal rubble 48
Are sorted by magnetic force or wind force. The char 33 is supplied to the crusher 5. The crusher 5 crushes the char and separates the char into a coarse char 36 having a particle diameter of 2 mm or more and a fine char 35 having a particle diameter equal to or less than the particle. The fine-grain char 35 is stored in the chamber 6, and is conveyed by air flow according to a load command from a control device (not shown).
Squirted to.

The melting furnace 12 is a cylindrical furnace.
A plurality of burners 11 are mounted on the inner wall surface. A swirling flow is formed in the melting and burning furnace 12 by the interaction of the air flow from the burner 11. The char is burned in the melting and burning furnace 12 to form a temperature atmosphere of 1200 ° C. or higher. The ash contained in the char is collected on the inner wall surface by the swirling flow formed in the melting and burning furnace 12 and turned into slag by the high temperature atmosphere. The slag is discharged from a slag elution port 13 provided at the furnace bottom, rapidly cooled by a water-sealed cooler 14, and recovered as a molten ash 51 by a discharger 15.
On the other hand, the exhaust gas 45 is exhausted from the upper part of the melting and burning furnace 12. Although a single burner 11 can generate a swirling flow in the melting and burning furnace 12, 4 to 16 burners 11
Is preferred. It is preferable that the ejection direction of the burner 11 is directed to the direction in contact with a circle smaller than the inner peripheral wall diameter. Since the melting and burning furnace 12 has a high temperature atmosphere of 1200 ° C. or more, the combustible components in the char burn at a high combustion efficiency of 99.9% or more. Thereby, the unburned carbon content involved in the production of dioxin decreases. On the other hand, harmful components such as heavy metals contained in the char are included in the molten slag. Since the molten ash 51 is solidified in a glass state, there is no possibility that heavy metals are eluted. After the exhaust gas 45 is exhausted from the melting and burning furnace 12, the heat exchanger 1
6. Air is exhausted from the chimney 24 through the air heater 18, the bag filter 23, and the moving layer 54. The heat exchanger 16 generates steam, which turns the turbine 17 to generate electricity.

The air heater 18 exchanges heat between the air 41 supplied from the blower 28 and the exhaust gas 45,
Is raised to 200 to 300 ° C. This air 41 is supplied to the burner 11 and used as combustion air.

The bag filter 23 is mounted under a temperature condition of 300 to 400.degree. Bag filter 23 is exhaust gas 45
The ash 44 contained in the water is collected. At the same time, heavy metals whose vapor partial pressure has decreased at this temperature are collected in the ash 44.
The ash 44 is returned to the burner 11 and turned into slag in the melting and burning furnace 12. As described above, the ash 44 is scattered to the downstream side by the exhaust gas 45. However, since the ash 44 is collected and slagged by the bag filter 23, there is no need to provide a device for melting the ash 44 separately from the municipal waste combustion device, and the device configuration And the efficiency of the system is increased. Furthermore, heavy metals can also be collected together with the ash 44 and included in the slag, so that scattering of heavy metals can be suppressed. The moving bed 54 has a duct 52 and a duct 53 before and after it, and the flow passage area is set to be about 1 m / s of the wind tower speed of the exhaust gas 45 in the moving bed 54. The moving layer 54 supplies the coarse-grained char 36 whose particle diameter has been adjusted from above. Coarse grain char 36
Is preferably adjusted to 2 mm or more. More preferably, the particles are sorted so as to have the same particle size, or the coarse-grained char 36
May be used after compression-solidifying and processing into pellets of uniform shape. The coarse-grained char 36 adsorbs a compound having a small vapor partial pressure such as a chlorine compound contained in the exhaust gas 45 and is discharged from the lower part of the moving bed 54. The following effects are obtained by attaching the moving layer 54 to the rear stage of the bag filter 23. Since the ash 44 is collected by the bag filter 23, an increase in the pressure loss of the moving bed 54 in a short time is suppressed. Further, since heavy metals are recovered together with the ash 44, the coarse-grained char 36 adsorbs a substance having a low vapor partial pressure and a chlorine-based compound. For this reason, in the water washing process described below, it is possible to specialize in removing chlorine compounds.

The coarse char 36 is washed by the washing machine 7 with the absorbing solution 39. The absorbing solution 39 is a suspension of an alkaline aqueous solution 50 in which an alkali metal hydroxide is dissolved. The alkaline aqueous solution 50 is calcium hydroxide, potassium hydroxide, magnesium hydroxide, sodium hydroxide, or the like. The method for cleaning the coarse-grained char 36 by stirring, ultrasonic waves or warm water is as follows.
It is effective in removing toxic substances having a small molecular weight. Chlorine compounds, especially HCl, are fixed as alkali metal chlorides and recovered by the salt ion recovery unit 9 as harmless solid salts 49. The absorption liquid 39 is circulated by the circulation pump 27,
The alkali aqueous solution 50 is supplied so that the alkalinity of the absorbing liquid 39 is constant. A substance having a larger molecular weight, for example, dioxin is adjusted so as not to be dissolved in the absorbing solution 39.

The char slurry 38 washed by the water washing machine 7 is separated into a char and an absorbing liquid by the dehydrator 8, and is recovered while adsorbing dioxin and heavy metals condensed at the temperature of the moving bed 54 on the char. This char is supplied to the melting and burning furnace 12. As a result, the combustibles of dioxins are 1
While being decomposed at a high temperature of 200 ° C. or more, heavy metals are fixed to the molten slag.

FIG. 2 shows another embodiment of the municipal solid waste combustion apparatus. In this embodiment, a pyrolysis furnace 2, a melting and burning furnace 12,
It comprises a heat exchanger 16, a turbine 17, an air heater 18, a cyclone 21, a bag filter 23, and a chimney 24. In the embodiment of FIG. 2, only the parts different from the embodiment of FIG. 1 will be described. In this embodiment, the refuse 1 is supplied to the melting and burning furnace 12 together with the calcium hydroxide. By adjusting the temperature and residence time of the pyrolysis furnace 2, chlorine derived from vinyl chloride contained in the refuse 1 is in the form of Ca (OH) Cl,
The aCl is recovered together with the char 33 as it is. The char 33 is made of metal rubble 48 using the sieve 4 and the crusher 5.
Is removed and supplied to the chamber 6.

The washing machine 7 is supplied with the char 37 from the chamber 6 and also with the absorbing liquid 39 from the circulation pump 27. The alkalinity of the absorbing solution 39 is adjusted with an aqueous alkaline solution 50. Ca (OH) contained in char 37
Cl or HCl forms an alkali metal chloride by the absorbing solution 39. At the same time, NaCl contained in the char 37 elutes into the absorbing solution 39. In order to promote these reactions, it is desirable that the molar ratio of the alkali metal contained in the absorbing solution 39 and the chlorine content in the char be 1 to 3. Making this molar ratio larger than 3 is not preferable from the viewpoint of economy. Further, this reaction is promoted by controlling the alkalinity of the absorbing solution 39 and by the action of stirring, ultrasonic waves or the like. The char slurry 38 is separated into a char 40 and an absorbent 39 by the dehydrator 8. The alkali metal chloride eluted in the absorbing solution 39 is recovered as the salt 49 by the salt ion recovery device 9. A suitable method for the salt ion recovery machine 9 is to heat and evaporate the absorbing solution 39 using exhaust gas as a heat source to concentrate the absorbing solution 39 to crystallize the salt. Using the exhaust gas 45 or the exhaust gas 47 on the upstream side of the moving bed as the heat source is suitable from the viewpoint of increasing the thermal efficiency of the municipal solid waste combustion device.

By the above series of processing, 90% or more of the chlorine contained in the char 37 is removed, and the chlorine contained in the char 40 is reduced. This desalting treatment has the following effects. First, since the concentration of the chlorine-based compound in the exhaust gas 45 of the melting combustion furnace 12 can be reduced, chlorine corrosion of the heat transfer tube in the heat exchanger 16 can be suppressed. This indicates that the steam temperature of the heat exchanger 16 is increased, and the power generation efficiency can be reduced from 15% in the conventional municipal solid waste combustion device to 20% to 30%. Become.
Next, the concentration of dioxins in the exhaust gas 45 is reduced to 0.1 ngT by the synergistic effect of reducing the chlorine concentration in the exhaust gas 45 and improving the combustion efficiency in the melting combustion furnace 12.
EQ / Nm ³ or less.

The method of supplying a part of the char 40 to the exhaust gas 45 is effective for removing heavy metals. In the embodiment shown in FIG. 2, the cyclone 21 and the bag filter 2
3 are arranged. The char 40 is mixed with the exhaust gas 45 by the char sprayer 19 provided in the duct 20 on the upstream side of the cyclone 21. The water content of the char 40 is
While being retained by the exhaust gas 45, and the char 40
Is dried and flows into the cyclone 21. The cyclone 21 has a char 46 having a particle diameter of 2 mm or more in the chamber 22.
And supplies the char 40 having a particle diameter smaller than the particle diameter to the bag filter 23. Air 4 supplied by compressor 29
3 transports the char 42 to the washing machine 7 by the ejector 25. The char supplied to the bag filter 23 accumulates on the filter surface and adsorbs harmful substances such as HCl and heavy metals remaining in the exhaust gas 45. These harmful substances are collected together with the ash 44 and supplied to the melting and burning furnace 12 through the burner 11. The ash 44 and heavy metals are included in the molten slag and collected as a glassy molten ash 51. On the other hand, since the char 42 adsorbs the HCl in the exhaust gas 45, it is possible to prevent the concentration of the chlorine-based gas from increasing due to the recirculation of the ash 44.

FIG. 3 shows another embodiment of the municipal solid waste combustion apparatus. In this embodiment, the thermal decomposition furnace 2, the heat treatment unit 57, the melting and burning furnace 12, the heat exchanger 16, the turbine 17, the air heater 18, the cyclone 21, the bag filter 23, and the chimney 24 are used.
Consists of In the embodiment of FIG. 3, only the portions different from the embodiment of FIG. 1 or FIG. 2 will be described.

In this embodiment, the fine-grained char 35a and the fine-grained char 35b
Distributed to The fine-grain char 35a is supplied to the melting and burning furnace 12 after being housed in the chamber 55. Fine Char 35
b is supplied to the heat treatment device 57. The heat treatment device 57 uses the part of the high-temperature gas 32 generated from the pyrolysis gas 30 to cause the fine-grain char 35b to stay in an inert gas atmosphere at 500 to 700 ° C. The fine char 35b is supplied from the char sprayer 19 to the duct 20. The hot gas 32 is the char sprayer 1
The gas is mixed with the exhaust gas 45 on the upstream side of 9. The heat treatment device 57 can increase the reaction activity by increasing the specific surface area of the fine char 35b. In this process, the amount of char used as an adsorbent can be made smaller than that in the embodiment shown in FIGS.

The chamber 22 collects a mixture of char having a particle diameter of 2 mm or more collected by the cyclone 21, char having a particle diameter of 2 mm or less collected by the bag filter 23, and ash 44 collected by the bag filter 23. Char 4 mixed with ash 44
6 is supplied to the washing machine 7 and mixed with the absorbing liquid 39 to form a char slurry 38. The char slurry 38 is separated by the dehydrator 8 into an absorbing solution 39 and a char 42, and HCl and NaCl contained in the char 42 are dissolved in the absorbing solution 39. The salt ion recovery machine 9 recovers the salt 49 from the absorbing solution 39.
On the other hand, the char 42 is supplied through the burner 11 to the melting furnace 12
And the heavy metals adsorbed on the ash 44 and the char are included in the molten ash. At the same time, dioxin is melted in furnace 1
Decomposition and detoxification at 2.

FIG. 4 shows still another embodiment of the municipal solid waste combustion apparatus. This embodiment includes a plurality of pyrolysis furnaces 2, a melting and burning furnace 12, a heat exchanger 16, a turbine 17, an air heater 18, a bag filter 23, and a chimney 24. The illustration of the heat exchanger 16, the turbine 17, and the chimney 24 is omitted. In the embodiment of FIG. 4, only the portions different from the embodiments of FIGS. 1 to 3 will be described.

In this embodiment, the first pyrolysis furnace 2 comprises:
A char 33 used as an adsorbent in the bag filter 23;
The char 33 that burns in the melting and burning furnace 12 is generated. Second
The subsequent pyrolysis furnace 2 is a char 3 burning in the melting combustion furnace 12.
3 is generated. Although not shown in FIG.
In No. 3, the metal rubble 48 contained in the char is removed.

A plurality of burners 11 are attached to the melting and burning furnace 12. The number of burners 11 and the number of pyrolysis furnaces 2 are desirably the same.
It is more desirable to be installed every time. Further, in addition to the burner 11, an auxiliary burner not shown in the embodiment of FIG. 4 is provided. This auxiliary burner supplies a combustion aid 58 to the melting combustion furnace 12 via the compressor 29. A gaseous fuel, a liquid fuel, or a solid fuel can be used for the auxiliary agent 58.

The melting and burning furnace 12 has a sensor for monitoring temperature conditions in the combustion furnace. The simplest sensor is a thermometer 59. The measurement position of the thermometer 59 is a duct of the exhaust gas 45 in the melting and burning furnace 12.
Attaching at this position is excellent in that the temperature change inside the melting and burning furnace 12 is quickly measured and that erosion of the thermometer 59 by molten ash is prevented.

The output signal of the thermometer 59 is input to the control device 60. The control device 60 controls the supply amount of the auxiliary combustion agent 58 so as to reduce the temperature change inside the melting combustion furnace 12.
This control is excellent from the viewpoint of keeping the heat input of the melting and burning furnace 12 constant. This control method can quickly absorb fluctuations in the calorific value of the char 33. As a result, the temperature inside the melting and burning furnace 12 can be controlled to be constant, so that the molten ash is well discharged from the slag elution port 13 to the cooler 14. Since the viscosity of the molten ash strongly depends on the temperature of the molten combustion furnace 12, the above-mentioned temperature control is important for stable operation of the municipal solid waste combustion apparatus.

Further, in this embodiment, the residence time of the pyrolysis furnace 2 for generating the char 33 used as the adsorbent is kept constant over a wider load range as compared with the case where a single pyrolysis furnace 2 is used. Therefore, the adsorption performance of the char 33 is kept constant.

[0040]

As described above, according to the present invention, chars generated by thermally decomposing municipal waste adsorb chlorine compounds and heavy metals, and the char is washed with an aqueous solution of an alkali metal to produce municipal waste. The chlorine contained is recovered as a salt, and the ash contained in the exhaust gas and the char that adsorbs dioxin and heavy metals are melted and burned. Therefore, harmful chlorine compounds and heavy metals are not discharged from the municipal solid waste combustion equipment to the outside of the combustion equipment.

Further, the present invention provides a municipal solid waste combustion apparatus in which a plurality of pyrolysis furnaces and a single melting and burning furnace are combined, so that the amount of adsorbent used is lower than when a single pyrolysis furnace is used. The adsorption performance is kept constant over a wide load range of the device.

Further, according to the present invention, since a sensor for monitoring the temperature state of the melting and burning furnace is provided, the temperature change inside the melting and burning furnace can be quickly measured, and the flow temperature condition of the molten ash can be kept constant by the supply amount of the auxiliary agent. Can be controlled.

[Brief description of the drawings]

FIG. 1 is a diagram showing a flow of a municipal solid waste combustion apparatus according to one embodiment of the present invention.

FIG. 2 is a diagram showing a flow of a municipal solid waste combustion apparatus according to another embodiment of the present invention.

FIG. 3 is a diagram showing a flow of a municipal solid waste combustion apparatus according to another embodiment of the present invention.

FIG. 4 is a diagram showing a part of a flow of a municipal solid waste combustion apparatus according to still another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Garbage, 2 ... Pyrolysis furnace, 3 ... Separation tower, 4 ... Sieve, 5 ... Crusher, 6, 22, 55, 56 ... Chamber, 7 ... Washer,
8 ... dehydrator, 9 ... salt ion recovery machine, 10 ... combustor, 11
... Burner, 12 ... Melting combustion furnace, 13 ... Slag leaching port, 1
4 ... cooler, 15 ... discharger, 16 ... heat exchanger, 17 ... turbine, 18 ... air heater, 19 ... char sprayer, 2
0, 52, 53 ... duct, 21 ... cyclone, 23 ... bag filter, 24 ... chimney, 25 ... ejector, 26, 28
... Blower, 27 ... Circulation pump, 29 ... Compressor, 3
0: pyrolysis gas, 31, 41, 43 ... air, 32: high temperature gas, 33, 37, 40, 42, 46 ... char, 35 ...
Fine char, 36 ... coarse char, 38 ... char slurry,
39 ... absorbent, 44 ... ash, 45, 47 ... exhaust gas, 48 ...
Metal rubble, 49 ... salt, 50 ... alkaline aqueous solution, 51 ... molten ash, 54 ... moving bed, 57 ... heat treatment device, 58 ... combustion agent,
59: thermometer, 60: control device.

Continued on the front page (51) Int.Cl. ⁶ Identification code FI B09B 5/00 ZAB B01D 53/34 136Z F23G 5/00 115 B09B 3/00 302F F23J 1/00 303L 15/00 ZAB 5/00 ZABL F23J 15 / 00 ZABJ (72) Inventor Tsuyoshi Shibata 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Inside the Hitachi Research Laboratory, Hitachi, Ltd. (72) Inventor Shin Tamada 3-1-1 Sachimachi, Hitachi City, Ibaraki Stock Inside the Hitachi Plant of Hitachi, Ltd.

Claims (6)

[Claims] 1. An apparatus for burning municipal solid waste, comprising: a pyrolysis furnace for pyrolyzing municipal solid waste to generate pyrolysis gas and char as a solid fuel; and an apparatus for separating metal rubble from the char. A melting furnace for burning the char separated from the metal rubble to melt the ash contained in the char, a heat exchanger for generating steam by the heat of the exhaust gas from the melting furnace, and warming the air supplied to the melting furnace. An air preheater, an ash collection device that collects ash contained in the exhaust gas, an adsorption device that adsorbs and collects gas components contained in the combustion exhaust gas by a char that separates metal rubble, and an adsorption device used in the adsorption device A municipal solid waste combustion device comprising an adsorbent treatment device for cleaning a char with an aqueous solution of an alkali metal. 2. The dehydration of the char used in the adsorption treatment device,
2. The municipal solid waste combustion apparatus according to claim 1, wherein the ash collected by the ash collector is supplied again to the melting and burning furnace. 3. An apparatus for burning municipal solid waste, comprising: a pyrolysis furnace for pyrolyzing municipal solid waste to produce pyrolysis gas and char which is a solid fuel; and an apparatus for separating metal rubble from the char. A treatment device for removing char contained in the char by washing the char separated from the metal rubble with an alkaline aqueous solution, a melting combustion furnace for melting ash contained in the char treated by the treatment device, and an exhaust gas of the melting combustion furnace A heat exchanger that generates steam with the heat of the heat, an air preheater that warms the air supplied to the combustion furnace, a device that collects ash contained in the exhaust gas, and a char that has passed through the processing device to generate a combustion exhaust gas. An apparatus for burning municipal waste, comprising: an adsorption device for adsorbing and collecting contained gas components; and means for returning the char that has passed through the adsorption device to the processing device. 4. A pyrolysis furnace for pyrolyzing municipal waste to generate pyrolysis gas and a solid fuel, char, and combusts the char generated in the pyrolysis furnace to melt ash contained in the char. A melting combustion furnace, a collector provided in a flue from the melting combustion furnace to the chimney, for collecting ash contained in flue gas generated by combustion of char, and adsorbing harmful gas contained in flue gas flowing through the flue. A municipal solid waste combustion device provided with an exhaust gas purifying device for removing by means of supplying at least a part of the char generated in the pyrolysis furnace to the exhaust gas purifying device as an adsorbent; and a device used in the exhaust gas purifying device. An apparatus for burning municipal solid waste, comprising: a cleaning device for cleaning char with an aqueous solution of an alkali metal; and means for supplying the char treated by the cleaning device to the melting and burning furnace. 5. A plurality of pyrolysis furnaces, a melting and burning furnace for burning the chars generated by the plurality of pyrolysis furnaces, and means for supplying the char generated by one of the pyrolysis furnaces to an adsorption device. The municipal solid waste combustion device according to any one of claims 1 to 4, further comprising: 6. A temperature measuring means for estimating the temperature of the melting and burning furnace, wherein the supply amount of either the char or auxiliary fuel generated in the pyrolysis furnace is adjusted based on the output signal of the temperature measuring means. The municipal waste combustion device according to any one of claims 1 to 5, characterized in that: