JP2956979B2 - Waste plastics combustion furnace and combustion equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a waste plastics combustion furnace and a combustion facility using the same. More specifically, the present invention relates to a waste plastics combustion furnace capable of constantly heating and melting waste plastics to be gasified, and capable of completely burning while supplying sufficient air, and a waste plastics combustion furnace generated during combustion. The present invention relates to waste plastics combustion equipment capable of detoxifying and exhausting harmful gases generated.

(Conventional technology and its problems) Conventionally, combustible waste such as industrial waste and garbage has been burned in an incinerator. For example, wastes made of plastics materials are usually treated by incineration.

Generally, it is known that the ignition temperature of a flammable solid substance is around 500 ° C.
It is also known that the volatile gas ignites at around 500 ° C., generating a flame.

However, plastics generally have a low-temperature melting property. For example, for polyethylene and polypropylene, the ignition temperature of their volatile gas is about 500 ° C. as described above, but their melting is ignition. It starts at about 120 ° C, which is much lower than the temperature. When burning plastics having such a low-temperature melting property, the melting temperature is significantly different from the combustion temperature, so that the melting speed is higher than the ignition speed, and as a result, the melting without gasification is performed. It is easy to fall under the grate in the state. The dropped melt is cooled to a temperature below the melting temperature and solidified, and remains in the incinerator. Removal of the residual plastics is not always easy, and also causes a reduction in the life of the incinerator.

Also, the temperature of the flame when burning plastics is
It is also known that the temperature is about 200 to 300 ° C. higher than general petroleum fuel. That is, while the temperature of the tip of a flame of a normal petroleum-based liquid fuel or gaseous fuel is about 1200 to 1300 ° C., in the case of plastics combustion, the temperature becomes about 1500 to 1800 ° C. For this reason,
In the design of incinerators, it is necessary to select materials that can withstand such high temperatures as furnace materials.

Furthermore, since plastics is a high-molecular polymer, incomplete combustion due to lack of air is likely to occur in its combustion, and toxic gases such as carbon monoxide, aldehydes, hydrogen chloride, and cyanogen gas are generated. There was also a problem that dust and soot were easily generated.

Gases that are toxic to the human body vary depending on the type of such plastics, but are generally as shown in Table 1.

For example, of the toxic gases shown in Table 1,
Carbon monoxide and aldehydes can be prevented from being generated by burning while sufficiently supplying air.

However, for hydrogen chloride and cyanide gas, increasing the amount of air only causes some decomposition,
It is difficult to completely remove the generated hydrogen chloride and cyan gas.

The present invention has been made in view of the above circumstances, eliminates the disadvantages of the conventional waste plastic combustion treatment, and can constantly heat and melt waste plastics, and furthermore, can be gasified. An object of the present invention is to provide a waste plastics combustion furnace capable of completely burning while supplying sufficient air, and a waste plastics combustion facility capable of detoxifying and exhausting toxic gas generated during the combustion. I have.

(Means for Solving the Problems) According to the present invention, as a means for solving the above-mentioned problems, a bottom portion having a conical projection concentric with an inner wall portion, and air for supplying air and combustion flame to the bottom portion from above. A melting / evaporating section provided with a supply port and a combustion flame supply port connected to a burner;
There is provided a waste plastics combustion furnace characterized in that a combustion section provided with an air supply port and a combustion flame supply port connected to a burner is provided above the combustion section.

The present invention also provides a waste plastics combustion facility which is connected to the waste plastics combustion furnace with a gas absorption tower and a duct for discharging exhaust gas.

(Operation) In the waste plastics combustion furnace of the present invention, a conical protruding body concentric with the inner wall is provided at the bottom, and a melting / evaporating unit for supplying necessary air and combustion flame from above the bottom is provided. As a result, the waste plastic can be melted and vaporized at all times, and the volatile gas can be completely burned in the combustion section provided above the melting and evaporating section. The combustion flame supplied from the melting / evaporation section and the combustion section can be swirl flame, and gasification and combustion of plastics can be effectively realized. For this reason,
Carbon monoxide, aldehydes was easy to occur, NO _x is not generated. No soot is generated.

Further, in the gas absorption tower of the present invention, the honeycomb-shaped toxic gas absorbing element disposed inside in a multi-stage manner,
Gas-liquid contact between the combustion gas and the toxic gas absorbing liquid can be sufficiently performed, and the ventilation resistance of the combustion gas can be reduced. The absorption rate of harmful gas components is improved.

Furthermore, in the waste plastics combustion facility of the present invention, the combustion gas can be completely detoxified and released to the atmosphere, and air pollution due to the waste plastics combustion treatment can be reliably prevented.

(Example) Hereinafter, an example is shown along with a drawing and the waste plastics combustion furnace and the combustion equipment of this invention are demonstrated in more detail.

FIG. 1 is a longitudinal sectional view showing an embodiment of a waste plastics combustion furnace according to the present invention. Also, FIG.
FIG. 2 is a cross-sectional view of the waste plastics combustion furnace illustrated in FIG.

As shown in this example, in the waste plastics combustion furnace of the present invention, an air supply port (4) is provided above a bottom (3) having a conical projection (2) concentric with the inner wall (1). And a melting / evaporating section (6) comprising a combustion flame supply port (5). The air supply port (4) and the combustion flame supply port (5) provided in the melting and evaporating section (6) are each inclined downward by an angle (θ ₁ ), and are provided at the bottom (3). The angle of inclination of the side surface of the conical protrusion (2) is substantially the same. Further, as shown in FIG. 2, the air supply port (4) and the combustion flame supply port (5) are arranged in parallel so as to be at an angle (θ ₂ ) from the tangential direction of the inner wall (1). I have. There is no particular limitation on the size of such angles (θ ₁ ) (θ ₂ ), and for example, each may be about 30 °. The air supply port (4) is connected to an air supply system such as a fan (not shown), and the combustion flame supply port is connected to a burner (7) that supplies liquid fuel or gas fuel. I have. Thus, the waste plastic to be supplied to the bottom portion (3) is provided by providing the conical protruding body (2) on the bottom portion (3) and arranging the air supply port (4) and the combustion flame supply port (5) in an inclined manner. The gas can be reliably melted and evaporated, and the volatile gas of the gasified waste plastic can be swirled inside the combustion furnace to form an upward flow. At the same time, the combustion flame supplied from the combustion flame supply port (5) also becomes swirling flame, and the inner wall portion (1) can be uniformly heated.

As described above, the material of the inner wall portion (1) can withstand a high temperature of about 1500 ° C. to 1600 ° C.,
Moreover, an appropriate material such as a stainless steel alloy having corrosion resistance can be used. Preferably, it can withstand up to about 2000 ° C.

As illustrated in FIG. 1, an air supply port (8) connected to an air supply system and a combustion flame supply port (10) connected to a burner (9) are provided above the melting / evaporating section (6). Combustion sections (11) provided on the left and right are also provided. The air supply port (8) and the combustion flame supply port (10) provided in the combustion section (11) are respectively provided so as to be orthogonal to the vertical inner wall section (1), and
Similar to the arrangement configuration of the air supply port (4) and the combustion flame supply port (5) of the melting / evaporation section (6) as illustrated in the figure,
It may have a configuration inclined with respect to the tangential direction of the inner wall portion (1). By doing so, the combustion flame in the combustion section (11) can be made to be swirl flame, and it is possible to effectively burn waste plastics.

In this way, the multi-stage configuration of the melting / evaporating section (6) and the combustion incineration (11) enables the inner wall of the combustion furnace (plastic) such as polyethylene or polypropylene to have a low-temperature melting property. The heating state of 1) can be sufficiently maintained, and the gasification of the melt can be promoted. Even if the melt drops to the bottom (3) after the melting, the molten state can be maintained, Moreover, the swirl flame supplied from the combustion flame supply port (5) allows the melt to be evaporated again. Along with this,
Air sufficient for combustion can be supplied into the combustion furnace from the air supply ports (4) and (8) provided in the evaporating section (6) and the combustion section (11), and complete combustion of waste plastics is realized. You. Further, depending on the material and the like of the waste plastic, it is also possible to burn in the melting / evaporation section (6), and further promote the combustion in the combustion section (11) to completely burn the waste plastic. . For this reason, even in the case of waste plastics that are contaminated with chemical substances, bacteria, viruses, etc. that are toxic or harmful to the human body, such as disposals that are discarded from hospitals, etc., these toxic and harmful elements can be easily removed. Combustion treatment can be performed while removing.

The combustion gas generated after the combustion can be guided to a predetermined portion of the gas absorption tower, which will be described later, through an exhaust port (12) provided above the combustion section (11).

In the example shown in FIG. 1, an inlet (13) for waste plastics is provided between the melting / evaporating section (6) and the combustion section (11). The waste plastics to be supplied are transferred to the bottom (3) by the piston (14). Another air supply port (15) is provided in the vicinity of the waste plastic input port (13) to further increase the amount of air supplied into the combustion furnace. Of course, there is no particular limitation on the configuration of such a combustion furnace, and in addition to the example illustrated in FIG. 1, for example, a configuration as illustrated in FIG. 3 may be employed.

That is, the combustion part (11) is located immediately above the melting / evaporation part (6).
It is also possible to install a waste plastic input section (17) having an input port (13) via a connection section (16). Further, the exhaust port (12) can be provided on the side of the combustion furnace. Furthermore, in addition to this example, it is also possible to arrange the combustion units (11) in multiple stages. An appropriate configuration can be adopted according to the amount of waste plastics to be burned, the size of the space in which the combustion furnace is installed, and the like.

FIG. 4 is a sectional view showing one embodiment of the gas absorption tower of the present invention.

In this example, a gas inlet (18) for introducing the combustion gas burned in the combustion furnace and an outlet (19) for discharging the absorbing liquid absorbing the harmful gas are provided at the lower part, and the harmless exhaust gas is provided. An exhaust port (20) for discharging and a supply port (21) for supplying a toxic gas absorbing liquid for removing toxic gas components contained in the combustion gas are provided at the upper part. The outlet (19) for discharging the toxic gas absorbing liquid is inclined to make the flow of the absorbing liquid smooth.

Inside the gas absorption tower, toxic gas absorption elements (22a) and (22b) for mixing flammable gas and toxic gas absorbing liquid in a gas-liquid mixture to remove toxic gas components contained in the combustion gas are arranged in two stages. ing. FIG. 5 shows a cross section of the harmful gas absorbing element (22a) (22b).

As exemplified in FIG. 5, the harmful gas absorbing element (22
a) (22b) has a honeycomb-shaped cross section, and makes the gas-liquid contact between the combustion gas and the toxic gas absorbing liquid sufficiently in the space (23) to reduce the absorption rate of the toxic gas component contained in the combustion gas. In addition to the improvement, the ventilation resistance of the combustion gas is reduced.

In addition, as illustrated in FIG. 4, by arranging the harmful gas absorbing elements (22a) and (22b) in two stages, the gas-liquid contact efficiency between the combustion gas and the toxic gas absorbing liquid is improved,
It is possible to completely remove toxic gas components contained in the combustion gas. Such a toxic gas absorbing element (22
a) The arrangement of (22b) is not particularly limited, and the arrangement can be further multi-tiered. Also, there is no particular limitation on the material, for example, a metal having corrosion resistance,
Suitable examples include polymers and ceramics.

A door (24) is provided at the center of the back of the gas absorption tower to facilitate replacement of the toxic gas absorption elements (22a) (22b).

Regarding the removal of toxic gas components contained in the combustion gas,
A lime emulsion (Ca (OH) ₂ ) or the like can be used as the toxic gas absorbing liquid. Of course, the harmful gas absorbing liquid is not limited to a lime emulsion (Ca (OH) ₂ ), and various liquids can be appropriately used.

When vinyl chloride, styrene, or the like is mixed in the waste plastics, the combustion gas contains hydrogen chloride (HCl), sulfuric anhydride (SO ₃ ), and sulfur dioxide (SO ₂ ). The harmful gas such as these causes a chemical reaction in the harmful gas absorbing elements (22a) and (22b) illustrated in FIG. 4 when they come into contact with the lime emulsion (Ca (OH) ₂ ), resulting in calcium chloride and calcium sulfate. And removed as calcium sulfide.

Further, cyan gas is also removed from the combustion gas by using an appropriate absorbing liquid.

In this way, the combustion gas is transferred to the harmful gas absorbing element (22
a) When passing through (22b), the harmful gas component is completely removed by the harmful gas absorbing liquid supplied from the supply port (21).

In order to supply the harmful gas absorbing liquid to the gas absorbing tower and discharge the same from the gas absorbing tower, for example, as shown in FIG.
A waste liquid port (26) connected to the absorption liquid recovery system or the like via 5) can be provided. Solid matter generated by absorbing and removing harmful gas components in the combustion gas is discharged from the waste liquid port together with the absorbing liquid. Although not shown, the absorbent having solids is passed through a recovery system connected to the waste liquid port (26), and is separated from the absorbent and discarded. A storage tank (27) for the toxic gas absorbing liquid is provided near the waste liquid port (26), and this storage tank (27) is connected to a conduit (28) connected to the supply port (21). A pump (29) is provided at a predetermined position of the conduit (28) to pump up the harmful gas absorbing liquid filled in the storage tank (27). Of course, the supply / discharge system of such a harmful gas absorbing liquid is not limited.

FIG. 6 is a sectional view showing the configuration of an embodiment of the waste plastics combustion equipment according to the present invention.

In this example, a waste plastics combustion furnace (A) illustrated in FIG. 1 and a gas absorption tower (B) illustrated in FIG. 4 are connected.

The air supply ports (4), (8), and (15) provided in the waste plastics combustion furnace (A) are connected to fans (30) and (31), and burn air from the fans (30) and (31). It is supplied inside the furnace. After completely burning the waste plastics in the waste plastics combustion furnace (A), the combustion gas is led to the gas absorption tower (B), where the harmful gas components contained in the combustion gas are removed and exhausted, as described above. Exhaust into duct (32) connected to mouth (20).
The duct (32) is provided with another fan (33) so that the exhaust gas can be reliably discharged to the atmosphere.

As described above, by combining the waste plastics combustion furnace (A) and the gas absorption tower (B), waste plastics contaminated by chemical substances, bacteria, viruses, and the like that are toxic or harmful to the human body, and harmful gas by combustion. Even in the case of waste plastics or the like, which may generate waste gas, it can be completely burned, and its exhaust gas is rendered harmless and released to the atmosphere. As a result, environmental pollution due to the waste plastic combustion processing can be prevented.

In this waste plastics combustion facility,
If it is made of only hydrocarbons such as polyethylene and polypropylene and there is no danger of generating harmful gases,
The combustion gas can be exhausted without passing through the gas absorption tower (B).

FIG. 7 is a sectional view showing the configuration of another example of the waste plastics combustion equipment of the present invention.

In this example, a waste plastics combustion furnace (A) illustrated in FIG.
4) is connected. The scrubber (34) adopts a method of showering a harmful gas absorbing liquid (35) from above, and has a harmful gas absorbing section (37) in which a porous material (36) made of ceramics or the like is stacked in multiple stages. . The lower part is provided with a waste liquid port (38). The combustion gas exhausted from the waste plastics combustion furnace (A) is supplied to the scrubber (34)
When it is introduced from the lower part and rises upward, it comes into contact with the shower-like toxic gas absorbing liquid (37) to remove its harmful gas components. The detoxified exhaust gas from which the harmful gas components have been removed is discharged into the atmosphere from the duct (32) as in FIG.

On the other hand, the harmful gas absorbing liquid having absorbed the harmful gas component is discharged from the waste liquid port (38) and guided to the precipitation tank (39).
In this sedimentation tank (39), the solid matter generated by the absorption of the harmful gas component is sedimented and separated, and the supernatant liquid is transferred to the stirring tank (40). Here, the mixture is mixed with a new harmful gas absorbing liquid (35) and adjusted to a certain concentration, and then supplied to the scrubber (34) by the pump (41).

Of course, the present invention is not limited by the above examples. The entire structure of waste plastics combustion furnace, gas absorption tower and waste plastics combustion equipment and their individual configurations, the arrangement angle of air supply port and combustion flame supply port provided in waste plastics combustion furnace, and dispose in gas absorption tower It goes without saying that various aspects are possible for the details of the shape and arrangement of the gas absorbing element and the type of the harmful gas absorbing liquid.

As detail above description (Effect of the Invention), this invention makes it possible to complete combustion of the waste plastics in the combustion furnace, carbon monoxide, aldehydes, it is possible to prevent the occurrence of NO _x. Further, even in the case of waste plastics contaminated with chemical substances, bacteria, viruses and the like that are toxic or harmful to the human body, it is possible to easily and completely burn the waste plastics. Hydrogen chloride, sulfurous acid gas, sulfuric anhydride, cyanide gas, etc., which may be generated by the combustion process, can be effectively absorbed by the toxic gas absorbing solution by the gas absorption tower connected to the combustion furnace, and the absorption rate is further increased. It can also be improved. The combustion gas can be sufficiently rendered harmless and released into the atmosphere. Therefore, there is no concern about environmental pollution. The waste plastics can be completely and highly efficiently burned.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of a waste plastics combustion furnace according to the present invention. FIG. 2 is an α-α sectional view of the waste plastics combustion furnace exemplified in FIG. FIG. 3 is a longitudinal sectional view showing another example of the waste plastics combustion furnace of the present invention. FIG. 4 is a sectional view showing one embodiment of the gas absorption tower of the present invention. FIG. 5 is a sectional view showing one embodiment of the harmful gas absorbing element. FIG. 6 is a sectional view showing the configuration of an embodiment of the waste plastics combustion equipment according to the present invention. FIG. 7 is a sectional view showing the configuration of another example of the waste plastics combustion equipment of the present invention. DESCRIPTION OF SYMBOLS 1 ... Inner wall part 2 ... Conical protruding body 3 ... Bottom part 4,8,15 ... Air supply port 5,10 ... Combustion flame supply port 6 ... Melting / evaporation part 7,9 ... Burner 11 ... … Combustion section 12,20… exhaust port 13… inlet port 14… piston 16… connection section 17… injection section 18… gas introduction section 19… exhaust port 21… supply port 22a, 22b… Hazardous gas absorption element 23 Space 24 Door 25 Backflow prevention valve 26, 38 Waste liquid port 27 Reservoir 28 Pipe, 29, 41 Pump 30, 31, 33 Fan 32 … Duct 34 scrubber 35 harmful gas absorbing liquid 36 porous material 37 harmful gas absorbing part 39 sedimentation tank 40 stirring tank

Claims (4)

(57) [Claims] 1. A melting / evaporating method comprising: a bottom having a conical protruding body concentric with an inner wall, an air supply port for supplying air and combustion flame from above to the bottom, and a combustion flame supply port connected to a burner. A waste plastics combustion furnace characterized by comprising a part and a combustion part provided with an air supply port and a combustion flame supply port connected to a burner above the part. 2. A waste plastics combustion facility comprising a waste plastics combustion furnace according to claim 1 connected to a gas absorption tower and an exhaust gas discharge duct. 3. The gas absorption tower has a combustion gas introduction port and a discharge port for discharging a toxic gas absorbing liquid at a lower portion, and has an exhaust port for discharging exhaust gas through a honeycomb-shaped toxic gas absorption element. 3. The waste plastics combustion equipment according to claim 2, wherein a supply port for supplying a toxic gas absorbing liquid is disposed at an upper portion. 4. The waste plastics combustion equipment according to claim 3, wherein a toxic gas absorbing element is arranged in multiple stages in the gas absorbing tower.