JP4063449B2 - Waste incineration gas reforming method, incineration gas reforming device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an incineration gas reforming method and apparatus for reforming an incineration gas of a waste incinerator and removing harmful components contained therein.
[0002]
[Prior art]
It is widely practiced to incinerate industrial waste and domestic waste (household waste). Since various harmful gases may be generated when these wastes are incinerated, severe restrictions are imposed on the operating conditions and location required for the incinerator.
[0003]
Therefore, in the conventional incinerator, the combustion temperature is strictly controlled to suppress the generation of harmful gas, or the kind of waste to be burned is limited. In addition, exhaust gas is purified by passing the incineration gas through an electric dust collector and a special harmful gas removal device.
[0004]
[Problems to be solved by the invention]
As the demand for exhaust gas purification has become increasingly severe in recent years, some existing incinerators have become difficult to meet this demand. In this case, it is necessary to stop the operation or to destroy the incinerator and rebuild it to the latest model. In particular, rebuilding an incinerator requires large-scale construction and a huge budget.
[0005]
OBJECT OF THE INVENTION
The present invention has been made in view of such circumstances, and the facilities are relatively simple, and it is possible to improve waste incineration gas that can utilize existing incinerators as they are to prevent generation of harmful gases and purify exhaust gases. The first object is to provide a quality method. A second object is to provide a reforming apparatus that is directly used for carrying out this method.
[0006]
[Structure of the invention]
The first object according to the invention, waste hot incineration gases leaving the combustion chamber of the incinerator, reforming said heated gas component by injecting the plasma jet towards the path of the incinerated gases This is achieved by a method for reforming waste incineration gas, which is characterized by preventing generation of harmful gas through a catalyst . That is, since the plasma jet becomes a high temperature of about 4,000 to 7,000 ° C, by heating the incineration gas with this plasma jet, various components in the incineration gas are decomposed into a plasma state and reformed into a completely different gas. Can do. In order to gas reformed by the plasma jet is prevented from changing again noxious gas by recombination, after heating at the plasma jet, Ru stabilized instead of harmless gases and particles by the catalyst.
[0007]
Here the plasma jet heat the incineration gases through the passage by injection into the incineration gas passage. That is, by applying a plasma jet to the hot incineration gases just leaving the incinerator is because it is possible to effectively utilize the incineration heat with incineration gas itself.
[0008]
The second object is achieved by a plasma torch which emits the plasma jet into the gas passage for guiding the incineration gases of high temperature exiting from the combustion chamber is discharged from the waste incinerator, and a catalyst provided downstream of the plasma torch The waste incineration gas reforming apparatus is characterized in that the incineration gas is heated and reformed by the plasma torch and then passed through the catalyst to prevent generation of harmful gas .
[0009]
Plasma torch used here, because provided between the incinerator and downstream of the exhaust treatment device, Ru can be used effectively heat energy of the exhaust itself immediately after leaving the incinerator. The exhaust treatment device where harmful gas removal equipment with catalyst is used. If the plasma torch is designed to inject the plasma jet obliquely in the downstream direction of the gas flow path, the flow direction of the shield gas and the incineration gas ejected from the plasma torch will match, and the incineration gas The flow is smooth.
[0010]
A plurality of plasma torches may be provided in the gas passage. The plasma torch used here applies a DC voltage between the center electrode and the nozzle electrode, sends a plasma working gas between the two electrodes to form a plasma gas, and ejects it from the nozzle electrode. A shield gas is supplied so as to surround the gas to eject a plasma jet flow.
[0011]
Embodiment
FIG. 1 is an overall view of an incinerator using one embodiment of the present invention, FIG. 2 is an enlarged perspective view of a cross section of the essential part, and FIG. 3 is a control system diagram of a plasma torch. In FIG. 1, reference numeral 10 denotes a dust pit, and 12 denotes a dust inlet. The garbage truck 14 throws in garbage from the garbage inlet 12 and the garbage is accommodated in the garbage pit 10.
[0012]
An incinerator 16 has a dry grate 18, a combustion grate 20, a post-combustion grate 22, an auxiliary burner 24, and the like. Garbage is thrown into the charging hopper 28 from the garbage pit 10 by the garbage supply crane 26, and the garbage thrown into the charging hopper 28 is sequentially sent to each grate 18, 20, 22 and burned. If necessary, the auxiliary burner 24 operates to assist incineration of garbage.
[0013]
30 is an ash removal device, and 32 is an ash pit. Garbage incinerated in each grate 18, 20, 22 becomes ash and falls to the ash removal device 30. The ash removal device 30 includes an ash removal conveyor, and sends the ash dropped from each grate 18, 20, 22 to the ash pit 32. The ash stored in the ash pit 32 is carried out by the ash crane 34.
[0014]
An incineration gas passage 36 guides the incineration gas from the incinerator 16 to the electric dust collector 38. The incineration gas is sucked into the suction blower 40 through the electric dust collector 38, and further led to the chimney 44 through the harmful gas removing device 42 having a catalyst . The electric dust collector 38 and the harmful gas removing device 42 form an exhaust treatment device.
[0015]
In the incineration gas passage 36, a plasma torch 46, a cooling device 48, and a cold water shower device 50 are sequentially provided from the incinerator 16 side toward the electric dust collector 38. The plasma torch 46 heats the incineration gas by injecting the plasma jet 52 into the gas passage 36 as will be described later. That is, the plasma jet 52 is an extremely high temperature (4,000 to 7,000 ° C.) plasma gas flow, and the incineration gas is heated to an extremely high temperature to reform its components.
[0016]
The cooling device 48 has a water pipe in close contact with the outside of the gas flow path 36. The cooling water is circulated in the water pipe to cool the inner wall of the gas passage 36, protect the inner wall from heat, and cool the incineration gas. To do. The cold water shower device 50 sprays the cooling water into the gas passage 36 in a shower shape, thereby bringing the cooling water into direct contact with the incineration gas. The incineration gas is directly cooled by the heat of vaporization of the cooling water. Cooling water that does not evaporate is sent to a purified water tank (not shown) to be purified, and then circulated again for use.
[0017]
The plasma torch 46 can be configured as shown in FIG. 3, for example. In FIG. 3, 54 is a center electrode, and 56 is a nozzle electrode surrounding the center electrode 54. A shield cap 58 surrounds the nozzle electrode 56. Cooling water is supplied to the electrodes 54 and 56 from the cooling water pump 60 and is always cooled. This cooling water is cooled and circulated through the heat exchanger 62.
[0018]
A plasma working gas is supplied from the plasma working gas supply means 64 between the center electrode 54 and the nozzle electrode 56. As this plasma working gas, argon gas, neon gas, oxygen gas, hydrogen gas, helium gas, air, a mixed gas thereof or the like is used. Here, air or a mixed gas mainly composed of air is used from the viewpoint of economy. A shield gas is supplied between the nozzle electrode 56 and the shield cap 58. As the shielding gas, air is used here from the viewpoint of economy. The shield gas is supplied from the shield gas supply means 66.
[0019]
A DC high voltage supplied from the controller 68 is applied between the center electrode 54 and the nozzle electrode 56. Here, the center electrode 54 is connected to the negative electrode (-electrode), and the nozzle electrode 56 is connected to the anode (+ electrode). The controller 68 is supplied with electric power generated using the exhaust heat of the incinerator 16.
[0020]
The incinerator 16 is provided with a furnace wall and a cooling pipe (not shown) heated by incineration gas, and transmits heat of the cooling liquid circulating through the cooling pipe to the turbine working liquid via the heat exchanger 70. The turbine working fluid is sent to the turbine 72 to drive the turbine 72. The coolant in the cooling pipe may be directly circulated to the turbine 72 without going through the heat exchanger 70. Further, the turbine 72 may be driven using the exhaust heat of the cooling device 48. The generator 74 is driven by the rotational output of the turbine 72. The electrical output of the generator 74 is sent to a transformer (transformer) 76, where it is converted to a predetermined voltage and then sent to a controller 68.
[0021]
When this plasma torch 46 is used, a plasma arc is generated when the plasma working gas passes through the gap between the center electrode 54 and the nozzle electrode 56. The plasma arc is ejected from the nozzle of the nozzle electrode 56, and the diameter of the plasma arc is reduced to a small size due to the pinch effect caused by the shielding gas cooling outside the plasma arc, and the inside of the arc is heated to an abnormally high temperature (4,000 to 20,000 ° C), and the degree of plasma (ionization) becomes stronger. For this reason, it is ejected as an ultra-high temperature plasma jet 52. The plasma jet 52 has a temperature of about 7,000 ° C. inside the excited jet jet and a temperature of about 4,000 ° C. near the tip.
[0022]
The incinerator gas discharged from the incinerator 16 is heated by the plasma jet 52 in the gas passage 36, whereby the incinerator gas component changes. For example, nitrogen oxide (NO _x ) is considered to be decomposed into nitrogen gas (N ₂ ) and oxygen gas (O ₂ ). Similarly, carbon oxides (CO, CO _2, etc.) are considered to be modified to carbon (C) and oxygen gas (O ₂ ). Ammonia gas (NH ₃ ) and dioxin are also considered to be decomposed and made pollution-free.
[0023]
These modified substances (gas) to prevent the underlying material (gas) recombine, Ru using quenched Ri catalyst. 1 and 2, the gas passage 36 is rapidly cooled by a cooling device 38, and generated particles (such as carbon) and water-soluble substances are captured using a water-cooled shower 50. As a result, the components of the gas entering the harmful gas removal device 44 having the electrostatic precipitator 38 and the catalyst are changed, and the gas components emitted from the chimney 44 to the atmosphere through these can be cleaned.
[0024]
In this embodiment, since the plasma torch 46 is attached to the gas passage 36 so that the plasma jet 52 is inclined in the gas flow downward direction, the flow direction of the plasma jet 52 is aligned with the gas flow direction. The flow becomes smooth. In this embodiment, one plasma torch 46 is attached to the gas passage 36, but a plurality of plasma torches 46 may be attached.
[0025]
FIG. 4 shows an embodiment in which two plasma torches 46A and 46A are attached. 4A is a side sectional view thereof, and FIG. 4B is a sectional view taken along the line BB. Here, the torches 46A and 46A are attached so that the gas flow downward direction is obliquely directed from the upper and lower walls of the gas passage 36A. By providing the plurality of plasma torches 46 and 46 in this way, the gas is heated more reliably, and the effect of the present invention is further enhanced. When a plurality of plasma torches are provided, they may be provided separately along the gas flow direction.
[0026]
【The invention's effect】
As described above, the invention of claim 1 heats the combustion gas with the plasma jet and reforms the gas component. Therefore, the harmful component can be reduced and the exhaust gas can be purified. In this case, since it can be carried out by attaching a plasma torch to the incinerator, the facility becomes simple and it is convenient because the existing incinerator can be used as it is.
[0027]
Since the plasma jet you to hit the incineration gases in the hot immediately after leaving the incinerator, we are possible to effectively utilize the heat of incineration gas itself, Ru economical der. Incineration gases can be prevented by passing the catalyze after modified with plasma jet, from changing the original harmful substances and other toxic substances bound once reformed gas again.
[0028]
According to invention of Claim 2 , the apparatus used directly for implementation of this method is obtained. Plasma torch Ru can effectively utilizing the heat held by the treasure incineration gases themselves provided in the gas passage between the incinerator and the catalyst. If the plasma torch injects the plasma jet obliquely in the gas flow direction, the flow of the plasma jet and the flow of the gas are aligned, and the flow of these becomes smooth (Claim 3 ). .
[0029]
Only one plasma torch may be provided in the gas passage, or a plurality of plasma torches may be provided. By providing a plurality, the incineration gas can be more reliably reformed (Claim 4 ). A plasma torch having the structure shown in claim 5 can be used. As the driving power of the plasma torch, the energy can be effectively used by using the power generated by using the exhaust heat of the incinerator (claim 6 ).
[Brief description of the drawings]
FIG. 1 is a general view of an incinerator using one embodiment of the present invention. FIG. 2 is an enlarged perspective view of a cross section of the main part. FIG. 3 is a control system diagram of a plasma torch. Illustration showing installation example [Explanation of symbols]
16 Incinerator 36 Gas passage 38 Electric dust collector 42 as exhaust treatment device Noxious gas removal device 46, 46A as exhaust treatment device Plasma torch 48 Cooling device 50 Cooling shower 52 Plasma jet 54 Center electrode 56 Nozzle electrode 58 Shield cap 68 Controller 74 Generator

Claims (6)

The hot incineration gases leaving the combustion chamber of the waste incineration furnace, and reformed the heated gas component by injecting the plasma jet towards the passage of the incineration gases, preventing the generation of harmful gases through the catalyst A method for reforming waste incineration gas, characterized in that Comprising a plasma torch which emits the plasma jet into the gas passage for guiding the hot incineration gases exiting the combustion chamber is discharged from the waste incinerator, and a catalyst provided downstream of the plasma torch, by the plasma torch A waste incinerator gas reforming apparatus, wherein the incinerator gas is heated and reformed and then passed through the catalyst to prevent generation of harmful gas . The waste incineration gas reforming apparatus according to claim 2 , wherein the plasma torch injects a plasma jet obliquely in a downstream direction of the gas passage. The apparatus for reforming waste incineration gas according to claim 2 , wherein a plurality of plasma torches are attached to the gas passage. The plasma torch is configured to send a plasma working gas between a central electrode to which a DC voltage is applied and a nozzle electrode so as to be ejected from the nozzle electrode as a plasma gas flow, and to eject a shielding gas surrounding the plasma gas flow from the outer periphery of the nozzle electrode. Item 2. A waste incineration gas reformer. The waste combustion gas reforming apparatus according to claim 2 , further comprising a generator driven by using exhaust heat of the incinerator, wherein the plasma torch is driven by using the power generation output of the generator.

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