JP2002333107A - Method and equipment for combusting waste containing agglomerate components - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a method and equipment for combusting agglomerative waste which can combust the agglomerative waste having agglomerate components (Na, K, P, Al and S) without bringing about lumps of ashes (clinkers) and can prevent clogging of a duct and fixing of fluidized sand. SOLUTION: In the present method for combusting the waste containing the agglomerate components, the waste A is charged in a furnace main body 2 and combusted in a boiled state together with a fluidizing medium, and combustibles are exhausted as exhaust gas from an exhaust tube 41, while incombustibles are discharged as ashes from drawing tubes 44 and 52 of a bed part 6. In this fluidized bed type combusting method, the waste A containing the agglomerate components such as Na, K, P, Al and S in large quantities is charged in the furnace main body 2 and granulated in a half-molten state, with the temperature of the bed part 6 set at 500-900 deg.C. The waste A is combusted in a fluidized state with the half-molten granules used as the fluidizing medium and the combustibles are combusted completely in the main combustion chamber 4 of the furnace main body 2 and exhausted from the exhaust tube 41, while the half-molten granules being the fluidizing medium are discharged as the ashes G and F from the drawing tubes 44 and 52 and recovered.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluidized bed combustion method in which waste such as municipal solid waste is fluidized and burned, and more particularly, to a method in which a large amount of agglomerated components such as Na, K, P, Al and S are contained. When combusting waste containing, these agglomerated components are melted in a semi-molten state to form semi-molten particles, the semi-molten particles are used as a fluid medium, and the waste is fluidly burned, and the agglomerated components are efficiently recovered as ash. The present invention relates to a method and an apparatus for burning waste containing flocculating components.

[0002]

2. Description of the Related Art Waste includes various kinds of waste such as municipal waste and industrial waste. When the waste is classified by its melting point, it is classified into waste having a high melting point and waste having a low melting point. Generally, combustible substances are removed as exhaust gas when the waste is burned, and finally, non-combustible substances remain. In the present invention, the melting point of the non-flammable residue is 500 ° C to 90 ° C.
The non-combustible residue distributed at 0 ° C. is called an agglomerated component, and a waste containing a large amount of the agglomerated component is called an agglomerated waste.

The main constituent element of the agglomerated component is sodium (N
a), potassium (K), phosphorus (P), and aluminum (Al), sulfur (S), and the like. The agglomerated component is a substance recovered as ash, for example, NaC
1, KCl, K ₂ SO _{4 and the} like.

[0004] Even if the melting point of a single substance exceeds 900 ° C, if the melting point of a mixture of the two substances falls to 900 ° C or less, this mixed substance is included in the concept of the agglomerated component. As an example where the melting point of the mixed substance is lowered, a mixture of NaCl and KCl will be described as an example. It is known that the melting point of NaCl is 803 ° C. and the melting point of KCl is 768 ° C. However, when KCl is added to NaCl, the melting point drops to 700 ° C. or less due to the freezing point drop.
A mixture of and KCl also becomes an aggregation component.

[0005] Waste containing these flocculated components is called flocculable waste. The cohesive waste includes, for example, soy sauce cake, coffee cake, straw, etc. When this cohesive waste is burned, combustibles are removed as exhaust gas, but non-combustibles remain as coagulation components, and the combustion device Of the combustion furnace by sticking to the wall surface of the wall, blocking the duct, or causing a failure of the combustion furnace.

[0006]

In recent years, due to the problem of dioxins, there is a tendency to increase the combustion temperature of municipal solid waste. Dioxin is found to be generated by low temperature combustion,
It was also found that high-temperature combustion can suppress the generation and decompose the generated dioxins and their precursors. Therefore, measures to completely burn garbage without generating dioxins by effective combustion gas stirring at a combustion temperature of 850 ° C. or more (preferably 900 ° C. or more) and a residence time of 2 seconds or more are being established.

This high temperature combustion technique has been introduced for many wastes. However, when this high-temperature combustion method is applied to the above-mentioned cohesive waste, heating at 850 ° C. or more is performed, so that most of the cohesive components remaining as incombustible components of the cohesive waste are converted into gas. It evaporates and is discharged as exhaust gas.

In this high-temperature combustion method, the temperature of the main combustion chamber and the bed of the combustion device is set to 850 ° C. or higher. Exists. Accordingly, the evaporated coagulation component is discharged from above the furnace body as coagulation exhaust gas, but the coagulation gas component coagulates on the wall surface of the low-temperature region to form ash clump (hereinafter, referred to as clinker). This clinker is a troublesome solid that cannot be easily peeled off because it sticks to the wall.

The clinker causes various troubles, such as clogging of a duct, causing abnormal combustion, and the use of sand as a fluid medium, causing the fluid sand to adhere and stop the operation of the incinerator. I was

[0010] Accordingly, an object of the present invention is to provide a method and an apparatus for burning a waste containing an agglomerated component, which can combust difficult-to-treat waste (or agglomerated waste) having an agglomerated component without generating clinker. The purpose is to provide.

[0011]

According to the first aspect of the present invention, waste is charged into a furnace body and burned in a boiling state together with a fluid medium, and combustibles are completely burned in a combustion chamber, and then discharged from an exhaust pipe as exhaust gas. In a fluidized bed combustion method in which exhaust is performed and non-combustible components are discharged as ash from a discharge pipe of a bed, Na · K ·
Waste containing a large amount of a coagulated component called P · Al · S is charged into the furnace body, the temperature of the bed is set to 500 ° C. to 900 ° C., and the waste is granulated in a semi-molten state. Is used as the fluid medium to flow and combust the waste, combustibles are completely burned in the main combustion chamber of the furnace body and exhausted from the exhaust pipe, and the semi-molten particles as the fluid medium are discharged as ash from the extraction pipe. This is a method for burning waste containing an agglomerated component, which is characterized in that the waste is recovered after being collected.

According to a second aspect of the present invention, there is provided the method for burning waste containing coagulated components according to the first aspect, wherein the vicinity of the extraction pipe is water-cooled to prevent ash from sticking to the vicinity of the extraction pipe. .

According to a third aspect of the present invention, when the temperature of the bed is lower than an appropriate temperature, the temperature of the primary air supplied to the bed is raised via a preheating device, and the heated primary air is cooled. The method for burning waste containing coagulated components according to claim 1, wherein the waste is supplied to the bed to raise and adjust the temperature of the bed to an appropriate temperature.

According to a fourth aspect of the present invention, when the temperature of the bed is higher than an appropriate temperature, water is sprayed on the bed to adjust the temperature of the bed to a proper temperature. It is a method of burning waste.

A fifth aspect of the present invention provides a furnace body for flowing and burning waste introduced from a waste introduction device, a preheater for adjusting the temperature of primary air, and a furnace body for heating the preheated primary air. Supply to the bed part and raise the bed part temperature 1
A secondary air nozzle, a water spray device that sprays water onto the bed to adjust the temperature of the bed to a low temperature, an extraction pipe that removes inflammable ash from the bed of the furnace body, and water cooling near the extraction pipe An apparatus for burning waste containing an agglomerated component, comprising a water-cooling jacket for preventing ash from sticking.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION
Incineration of cohesive waste having a coagulation component at 900 ° C.,
As a result of intensive research to efficiently collect the ash,
500 ° C to 900 ° C, the melting point of the bed of the furnace body
To make the agglomerated component into semi-molten particles, use the semi-molten particles instead of sand as the fluid medium to efficiently combust the cohesive waste in the boiling state, and efficiently collect the semi-molten particles as ash We came up with a new burning method.

In this combustion method, the bed temperature is 500
Since the temperature is set to between 900C and 900C, the agglomerated component only becomes a semi-molten state and becomes particles, and almost no evaporation of the agglomerated component occurs. In other words, since the agglomerated component is not discharged as exhaust gas, it does not agglomerate and adhere to a low-temperature portion such as a duct, and the piping system of the combustion device can be kept clean.

The agglomerated components that have become semi-molten particles are brought into a boiling state by blowing primary air, and the cohesive waste is finely and reliably burned by the semi-molten particles that boil and disturb, and the combustible components are burned by the combustion. It becomes exhaust gas and is efficiently exhausted and removed.

Also, since sand is not used as a fluid medium,
The durability of the furnace main body can be improved without the furnace main body being damaged by the sand that is flowing and turbulent. Further, the non-combustible component becomes semi-molten particles as an agglomerated component, and the semi-molten particles are discharged from the bottom or upper portion of the bed portion through an extraction pipe, and are efficiently collected as ash when the temperature is lowered.

Hereinafter, embodiments of the method and apparatus for burning waste containing coagulated components according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic configuration diagram of an embodiment of a combustion apparatus according to the present invention. The furnace body 2 is composed of an upper main combustion chamber 4 and a lower bed 6 on which waste is deposited. The waste A is injected into the furnace main body 2 from the waste input device 8.

The primary air B is supplied to the supply pipe 30 via the preheating device 10 and blown from the primary air nozzle 32 into the bed 6 as hot air. The preheating device 10 includes two systems: a bypass line 14 for supplying the primary air B without preheating, and a main line 12 for supplying the preheated air. The bypass line 14 includes a flow controller 26 and a primary air supply unit 2.
The primary air B at room temperature, which has been flow-regulated and has been adjusted at normal temperature, is sent from the primary air nozzle 32 to the bed 6 as it is. That is, the bypass line 14 is used not only for supplying air but also for cooling the bed temperature.

Primary air B flowing from the main line 12
The flow rate is controlled by a flow controller 16, preheated to a predetermined temperature by a preheater 18 having a heater 20 therein, and supplied to a primary air supply unit 28. The preheated primary air B is supplied from the primary air nozzle 32 to the bed 6 to assist the combustion of the waste A in the bed 6. Preheated 1
When the supply of the next air B is cut off, the preheated air is discharged to the outside by the discharge line 22 and the flow rate controller 24.

When the cohesive waste A is injected from the waste input device 8, the waste A is burned in the bed 6, and the combustibles are burned to become volatiles 36 to the main combustion chamber 4. To rise. The secondary air C blown from the blowing nozzle 38 completely burns the volatile matter 36, is discharged from the exhaust pipe 41 as a complete combustion gas 40, and the exhaust gas D is discharged to a subsequent device.

The bed 6 is set at a temperature at which the coagulated component of the coherent waste A, that is, the non-combustible component is melted. In the present invention, since the melting point of the agglomerated component is defined as 500 ° C to 900 ° C, the temperature of the bed 6 is adjusted to its melting temperature range, that is, 500 ° C to 900 ° C. Therefore, the agglomerated component is melted in the semi-molten state in the bed 6 and takes a semi-molten particle form due to surface tension.

The semi-molten particles are innumerably formed in the bed 6 and fluidize the entire bed 6 to a boiling state while being disturbed by the supply of the preheated primary air B. That is, in the present invention, the semi-molten particles of the agglomerated component become the fluid medium, and the cohesive waste A is fragmented and efficiently burned by the boiling of the fluid medium.

Generally, in a fluidized combustion furnace, sand is used as a fluid medium, and the combustion of the bed accelerates due to the boiling disturbance of the sand. In the present invention, the sand is not used as the fluid medium, and the semi-molten particles formed by converting the agglomerated components of the waste material into the semi-molten state are used as the fluid medium. Can be improved.

The semi-molten particles and other ash (solid components) fall into a lower extraction pipe 44 provided at the lower part of the bed 6 and are discharged to a water cooling screw device 48. The semi-molten particles are cooled to ash during the discharging process. The ash is pumped by a screw, and the discharge port 48b and the discharge pipe 48c
Is supplied to the vibrating screen device 50 via the.

The bottom of the furnace body 2 is a hopper section 42 having a tapered cross section, and ash falls from the hopper section 42 by its own weight. A lower water cooling jacket 46 is provided around the hopper section 42 and the lower extraction pipe 44 to prevent ash from sticking to the wall surface. The water W is configured to enter from the inlet 46a and exit from the outlet 46b.

Further, semi-solid particles and other ash (solid components)
Overflows from the surface of the bed 6 and is discharged from the upper extraction pipe 52. Also in this discharging process, the semi-molten particles are cooled and become ash. This upper extraction pipe 52
A water cooling jacket 54 is also arranged around the
Water W flows from 4a to the outlet 54b to cool the vicinity and prevent ash from sticking to the wall surface.

The ash discharged from the upper extraction pipe 52 is transferred from the discharge port 52b to the discharge pipe 56 and further to the discharge pipe 48c by its own weight, and all the discharged ash is supplied to the vibrating screen device 50. .

In the vibrating screen device 50, the ash vibrates while falling on the filter 57, and the coarse ash F having a large particle size falls from the discharge port 58 while riding on the filter 57 and is collected as the ash deposit 60. You. The fine ash G falls from the filter 57, and is discharged from the outlet 62 and the feedback pipe 64.
Is returned from the charging pipe 66 to the inside of the furnace main body 2. Therefore, the fine ash G falls on the bed 6 and repeats the above-described process again.

In the present invention, since the coagulated component is converted into semi-molten particles and used as a fluid medium, setting the temperature of the bed 6 is extremely important. The temperature of the bed 6 needs to be set at 500 ° C. to 900 ° C., which is the melting point of the agglomerated component
It fluctuates up and down according to the combustion rate of the waste A. In particular, in order to granulate the agglomerated component into semi-molten particles, it is necessary to adjust the balance between the adhesion force between the particles based on the cohesion and the dissociation force between the particles due to fluidization, and the bed temperature is set to a predetermined value It is desirable to control within ± 20 ° C. based on the above.

Therefore, a heating means and a cooling means are required to control the temperature of the bed 6 within the above-mentioned error range. As the heating means, a primary air B preheating device 10 is used. The preheater 18 is equipped with a heater 20, and the temperature of the primary air B can be controlled by the heater 20 to raise the temperature of the bed 6 to a predetermined temperature when the temperature of the bed 6 is low.

As the heater 20, exhaust gas D discharged from the main combustion chamber 4 is used, high-temperature steam generated by driving a boiler by exhaust heat of the main combustion chamber 4 is used, or an electric heater is used. Or you can.

As a cooling means for the bed 6, there is a water spraying device 35 for spraying the cooling water W onto the bed 6. The water spray device 35 is configured to connect a water pipe from the outside to the inside of the furnace main body 2 and spray water to cool the bed 6 to a predetermined temperature when the temperature of the bed 6 becomes higher than a predetermined temperature.

The combustion method of the present invention is characterized in that semi-molten particles obtained by melting and aggregating agglomerated components are effectively used as a fluid medium without using sand as fluidized sand. However, it is preferable to use liquid sand when starting the combustion furnace. That is, it is desirable that sand is placed in a furnace, and the sand is boiled and fluidized in the initial stage to promote the combustion of the waste A. As this sand, silica sand having a particle size of 0.1 to 3.0 mm is used.

After the fluidized combustion reaches the stable stage, silica sand is not required, and the semi-molten particles of the agglomerated component function as fluidized sand. Therefore, the fluid sand may be collected in the ash deposit 60 by adjusting the mesh of the filter of the vibrating screen device 50. When the mesh is coarsened, the sand returns to the bed 6 again via the feedback pipe 4 and continuously functions as fluidized sand. In this case, both the fluidized sand and the semi-molten particles can be used as the fluidized medium.

The present invention is not limited to the above embodiments and examples, but includes various modifications and design changes within the technical scope without departing from the technical idea of the present invention. Needless to say.

[0040]

According to the first aspect of the present invention, since the waste is burned near the melting point of the agglomerated component, the agglomerated component contained in the waste is granulated in a semi-molten state, and the semi-molten particles are used as a fluid medium. Utilization makes it possible to increase the efficiency of fluid combustion of waste, and because semi-molten particles are extracted and collected as ash, no flocculated components adhere to the wall surface or block the ducts, and when flocculated components are contained The certainty and stability of fluid combustion can be achieved.

According to the second aspect of the present invention, since the vicinity of the extraction pipe for extracting the ash to the outside is cooled with water, the ash does not adhere to the vicinity of the extraction pipe. It can be collected reliably.

According to the third aspect of the present invention, the preheating device
Because the temperature of the primary air can be adjusted freely, even if the bed temperature is lower than the appropriate temperature, the bed temperature can be immediately raised to the melting point temperature of the agglomerated component, and the fluidized combustion is stabilized by the agglomerated component. It is possible to maintain the efficiency of the ash recovery of the agglomeration and aggregation components.

According to the fourth aspect of the present invention, even when the temperature of the bed is higher than the appropriate temperature, water can be sprayed on the bed to control the temperature of the bed to a low temperature of the melting point of the coagulated component. It is possible to stabilize fluid combustion by the components and to improve the efficiency of ash recovery of the coagulated components.

According to the invention of claim 5, a device for burning waste containing coagulated components can be specifically configured, and the effects of claims 1 to 4 can be realized as a specific device. As described above, the present invention has excellent practical utility.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of a combustion device according to the present invention.

[Explanation of symbols]

2 is a furnace body, 4 is a main combustion chamber, 6 is a bed section, 8 is a waste charging device, 10 is a preheating device, 12 is a main line, 14
Is a bypass line, 16 is a flow controller, 18 is a preheater,
20 is a heater, 22 is a discharge line, 24 is a flow controller,
26 is a flow controller, 28 is a primary air supply unit, 30 is a supply pipe, 32 is a primary air nozzle, 34 is a fluidized bed, 35 is a water spray device, 36 is volatile matter, 38 is a blowing nozzle, and 40 is complete Combustion gas, 41 is an exhaust pipe, 42 is a hopper section, 44 is a lower extraction pipe, 46 is a lower water cooling jacket, 46a is an inlet,
46b is an outlet, 48 is a water-cooled screw device, 48b is a discharge port, 48c is a discharge pipe, 50 is a vibrating screen device, 5
2 is an upper extraction pipe, 54 is an upper water cooling jacket, 54a is an inlet, 54b is an outlet, 56 is a discharge pipe, 57 is a filter,
58 is an outlet, 60 is an ash deposit, 62 is an outlet, 64 is a feedback pipe, 66 is an input pipe, A is waste, and B is 1
Secondary air, C is secondary air, D is exhaust gas, E is a fluid medium, F
Is coarse ash, G is fine ash.

Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat II (Reference) F23G 5/30 F23C 11/02 308 5/44 ZAB 311 F Term (Reference) 3K064 AA04 AA18 AB03 AC02 AC06 AC12 AD08 AE08 AE13 AF01 AF10 3K065 AA11 AB03 AC01 BA04 BA08 HA05

Claims (5)

[Claims] 1. A waste containing a large amount of a coagulated component such as Na, K, P, Al, S is charged into a furnace body, and the temperature of a bed portion is set at 500 ° C to 900 ° C, so that the waste is in a semi-molten state. The waste is flow-combusted using the semi-molten particles as a fluid medium, the combustibles are completely burned in the main combustion chamber of the furnace body and exhausted from an exhaust pipe, and the semi-molten particles as the fluid medium are discharged. A method for burning waste containing coagulated components, wherein the waste is collected by discharging as ash from an extraction pipe. 2. The method of burning waste containing coagulated components according to claim 1, wherein the vicinity of the extraction pipe is water-cooled to prevent ash from sticking to the vicinity of the extraction pipe. 3. When the temperature of the bed is lower than an appropriate temperature, the temperature of the primary air supplied to the bed is increased through a preheating device, and the heated primary air is supplied to the bed. The method for burning waste containing coagulated components according to claim 1, wherein the temperature of the bed portion is adjusted to an appropriate temperature by heating. 4. The combustion of waste containing coagulated components according to claim 1, wherein when the temperature of the bed is higher than an appropriate temperature, water is sprayed on the bed to adjust the temperature of the bed to a proper temperature. Method. 5. A furnace main body for flowing and burning the waste input from the waste input device, a preheater for adjusting the temperature of the primary air, and supplying the preheated primary air to a bed portion of the furnace main body. A primary air nozzle that raises and adjusts the bed temperature
A water spraying device that adjusts the bed temperature to a low temperature by spraying water on the bed, an extraction pipe that removes non-combustible ash from the bed of the furnace body, and ash adheres by water cooling near the extraction pipe An apparatus for burning waste containing an agglomerated component, comprising a water-cooled jacket for preventing waste.