JP3913684B2 - Waste gasification and melting system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fluidized bed gas constituting the first stage in a gasification and melting system for treating waste such as municipal waste, solidified fuel (RDF), waste plastic, waste FRP, biomass waste, automobile waste, waste oil and the like. The present invention relates to a processing apparatus and a processing method for processing a combustible gas leaking from an incombustible discharge line installed at the bottom of a chemical reactor.
[0002]
[Prior art]
As shown in FIG. 3, the fluidized bed gasification furnace 11 has a diffuser plate disposed on the furnace bottom 11 a, combustion air b for partial combustion is supplied from the furnace bottom 11 a, and the fluidized medium p is supplied onto the diffuser plate. A fluidized bed is formed. When the waste a supplied to the fluidized bed gasification furnace 11 falls into the fluidized bed, it is quickly pyrolyzed by contacting the fluidized medium heated to 450 to 750 ° C. and the combustion air, and combustible gas ( (Including flammable components), tar, and solid carbon.
[0003]
The gaseous gas and tar generated by the thermal decomposition are discharged from the outlet duct 11b of the fluidized bed gasification furnace 11 together with fine solid carbon. Solid carbon having a large particle size generated during pyrolysis is finely pulverized by vigorous disturbing motion of the fluidized bed and partial combustion, and is then discharged from the outlet duct 11b along with the gas and tar.
On the other hand, incombustible materials such as iron, aluminum, copper, and debris contained in the waste are discharged from the bottom of the furnace together with the fluid medium p through the in-furnace chute 12 and then sent to the incombustible material processing facility.
[0004]
As shown in FIG. 3, the conventional incombustible material treatment facility includes an incombustible material discharge device 21, a vibration sieve 23, a sand circulation elevator 24, and a sand injection valve 25. The mixture of the incombustible material and the fluidized medium discharged from the furnace bottom 11 a of the fluidized bed gasification furnace 11 passed through the lower furnace chute 12, carried out by the incombustible material discharge device 21, and sent to the vibrating sieve 23. Then, the vibrating sieve 23 separates the incombustible material having a large particle size into a fluid medium having a small particle size, and the separated fluid medium is conveyed in the vertical direction by the sand circulation elevator 24, and is fluidized through a sand input valve. It was returned to the gasifier 11. Non-combustible materials including iron, aluminum, copper, rubble, etc., which were separated by the vibration sieve 23, were disposed of in landfills after recovering valuable materials such as metals.
[0005]
[Problems to be solved by the invention]
Normally, the freeboard part of the fluidized bed gasifier is kept at a negative pressure of about several tens of mmH ₂ O. However, when the fluidized medium is fluidized, pressure loss occurs above and below the fluidized bed, so the furnace bottom is at a positive pressure. It becomes. Therefore, the leakage of flammable gas is prevented by filling the mixture of the fluid medium and the incombustible material in the in-furnace chute and the incombustible material discharge device and performing the material seal. A mechanical seal means represented by a double damper may be installed between the incombustible discharge device and the vibrating screen to further ensure the prevention of flammable gas leakage.
[0006]
Actually, it is difficult to completely seal a material seal by filling the in-furnace chute and the incombustible material discharge device with a mixture of a fluid medium and an incombustible material, and a gas flow occurs due to a pressure difference in the material seal part. Causes flammable gas leakage. Even when a double damper, which is a mechanical seal means, is provided, the combustible gas leaks due to the differential pressure before and after the double damper when the double damper is opened and closed. Furthermore, complete sealing with a double damper under operating conditions of high-temperature powder is technically difficult, and sealing of the double damper becomes incomplete due to biting or the like, causing leakage of combustible gas. The leaked combustible gas may contain a trace amount of harmful components, but it was released into the atmosphere only by dust removal even if it was left untreated or treated. If the leaked combustible gas stays around the incombustible material discharge facility, the working environment may be significantly deteriorated.
[0007]
The present invention provides a processing apparatus and a processing method capable of preventing the combustible gas discharged from the fluidized bed gasifier furnace bottom through the incombustible material discharging means from being released into the atmosphere and appropriately processing it. For the purpose.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, a gasification and melting system according to the present invention includes, for example, a fluidized bed gasification furnace 11 for gasifying waste a and a product generated in the gasification furnace 11, as shown in FIG. In a gasification and melting system comprising a melting furnace 31 that melts and burns; a non-combustible material contained in the waste a from the bottom 11a of the gasification furnace 11 together with a fluid medium, and a material seal is performed between the incombustible material and the fluid medium Incombustible matter discharging means 21 for discharging while : means 23 for separating the discharged incombustible substance and fluid medium; and means for discharging the combustible gas leaking from the gasification furnace 11 through the incombustible matter discharging means from between the outlet side upper or means 23 for separating the incombustible discharge means 21 of 21, the mixed gas suction means 1a for mixed gas sucked by the blower together has passed the means 23 for separating air Combustion air supply means 41 and 42 for supplying combustion air and the mixed gas to at least one of the gasification furnace 11 and the melting furnace 31; and conveying the mixed gas to the combustion air supply means 41 and 42 A mixed gas transport means 65 is provided.
[0009]
If comprised in this way, the mixed gas which conveys mixed gas to the combustion air supply means which supplies the mixed gas containing a combustible gas to at least any one of a fluidized bed gasification furnace or a melting furnace, and a combustion air supply means Since the conveying means is provided, the amount of flammable gas dissipated into the atmosphere is reduced as much as possible, and can be appropriately processed. Moreover, since it suck | inhales with an air blower, the mixed gas containing a combustible gas can be processed safely in a gasification melting system. It is particularly suitable when the treated combustible gas contains a trace amount of harmful components.
[0010]
As shown in FIG. 1, for example, the gasification melting system according to the present invention includes a fluidized bed gasification furnace 11 for gasifying waste a and a melting furnace for melting and burning products generated in the gasification furnace 11. in gasification melting system consisting of 31; with incombustible the fluidized medium contained in the furnace bottom 11a wastes from a gasifier 11, incombustible discharge for discharging while material seal between the incombustible and flowable media means 21 and; said the discharged incombustibles a means 23 for separating for separating the fluid medium; outlet side upper portion of the incombustible discharge means 21 the combustible gas leaked from the gasification furnace 11 through the incombustible discharge means or from between the means 23 for separating the incombustible discharge unit 21, and the mixed gas suction means 1a a mixed gas sucked by the blower together has passed the means 23 for separating air; the mixed gas Comprising a mixed gas conveying means 65 for conveying at least either one of the gasification furnace 11 or melting furnace 31.
[0011]
By comprising in this way, since the mixed gas containing combustible gas can be guide | induced to at least one of a fluidized bed gasification furnace or a melting furnace, the quantity which dissipates combustible gas in air | atmosphere reduces as much as possible. Can be processed appropriately. Moreover, since it suck | inhales with an air blower, the mixed gas containing a combustible gas can be processed safely in a gasification melting system. It is particularly suitable when the treated combustible gas contains a trace amount of harmful components.
[0012]
The gasification and melting system according to the present invention may include means 1b for removing dust from the mixed gas in the gasification and melting system.
[0013]
If comprised in this way, since the dust in mixed gas will be removed by the means which removes the said mixed gas, the long-term stable operation | movement of a gasification melting system will be attained. In particular, when a means for removing dust is provided in front of the mixed gas suction means as shown in FIG. 1, for example, dust troubles in a blower that is the mixed gas suction means can be avoided.
[0014]
Further, in the gasification and melting system according to the present invention, for example, as shown in FIG. 2, the mixed gas suction means 1a is a mixture for sucking the combustible gas from between the nonflammable material discharge means 21 and the means 23 for separating. A gas suction means 1a; provided with a mechanical sealing means 22 disposed between the non-combustible discharge means 21 and the separating means 23; the mixed gas suction means 1a is flammable from the downstream side of the mechanical sealing means 22; Gas may be aspirated.
[0015]
By comprising in this way, since a mechanical sealing means is provided, the quantity of the combustible gas which leaks can further be reduced. Further, since the combustible gas is sucked from the downstream side of the mechanical seal means, it is possible to prevent the combustible gas in the gasification furnace from being forcibly sucked.
[0016]
Moreover, in embodiment which concerns on this invention, as shown , for example in FIG. 1, after gasifying the waste a in the fluidized bed gasification furnace 11, the product produced | generated in the gasification furnace 11 is made into the melting furnace 31. In the gasification and melting method of waste that melts and burns; combustible gas that leaks when incombustible material contained in the waste a is discharged together with air from the bottom 11a of the gasification furnace 11 together with air A method of gasifying and melting waste that is supplied to at least one of the fluidized bed gasification furnace 11 and the melting furnace 31 together with combustion air after transporting the mixed gas can be used.
[0017]
With this configuration, for example, as shown in FIG. 1, the mixed gas containing the treated combustible gas is supplied to at least one of the fluidized bed gasification furnace and the melting furnace. The amount dissipated inside can be reduced as much as possible, and can be handled appropriately. It is particularly suitable for processing when the combustible gas contains a trace amount of harmful components.
[0018]
Moreover, in embodiment which concerns on this invention, as shown , for example in FIG. 1, after gasifying the waste a in the fluidized bed gasification furnace 11, the product produced | generated in the gasification furnace 11 is made into the melting furnace 31. In the gasification and melting method of waste that melts and burns; combustible gas that leaks when incombustible material contained in the waste a is discharged together with air from the bottom 11a of the gasification furnace 11 together with air As a gas, a waste gasification melting method in which the mixed gas is supplied to at least one of the fluidized bed gasification furnace 11 and the melting furnace 31 can be used.
[0019]
If comprised in this way, since the mixed gas containing a combustible gas can be guide | induced to at least any one of the fluidized bed gasification furnace 11 or the melting furnace 31, the quantity which dissipates combustible gas in air | atmosphere will reduce as much as possible. Can be processed appropriately. It is particularly suitable for processing when the combustible gas contains a trace amount of harmful components.
[0020]
In the embodiment according to the present invention, the mixed gas may be dedusted in the waste gasification and melting method.
[0021]
With this configuration, for example, as shown in FIG. 1, dust in the mixed gas is removed by the dust removing device 1b, so that dust troubles in the blower 1a can be avoided, and gasification and melting can be performed stably for a long period of time. It becomes.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the mutually same or equivalent member, and the overlapping description is abbreviate | omitted.
[0023]
With reference to FIG. 1, the gasification melting system which is the 1st Embodiment of this invention is demonstrated. This figure shows the fluidized bed gasification furnace 11 and a large amount of combustible gas sucked from the atmosphere including a small amount of harmful components discharged from the bottom of the fluidized bed gasification furnace through the lower chute 12 and the incombustible material discharge device. It is a block diagram of the gasification melting system which shows the structure provided with the mixed gas processing apparatus 1 of the mixed gas which consists of air, and the conveyance flow path 65 which guides the mixed gas containing the processed combustible gas.
[0024]
Waste as the object to be treated is supplied to the fluidized bed gasification furnace 11 and thermally decomposed into combustible gas, tar and solid carbon in a fluidized bed maintained at 450 to 750 ° C. The fluidized bed gasification furnace 11 has an outlet duct 11b, and most combustible gas and tar generated by pyrolysis in the fluidized bed gasification furnace 11 are discharged from the outlet duct 11b with fine solid carbon, It is introduced into the swirl melting furnace 31. Coarse incombustible materials such as iron, aluminum, copper, rubble and the like are extracted from the furnace bottom 11a of the gasification furnace together with the fluid medium, and are sent to the incombustible material unloading device 21 through the furnace bottom chute 12. The mixture of the incombustible material and the fluid medium discharged from the incombustible material carry-out device 21 is separated into the incombustible material having a large particle size and the fluid medium having a small particle size by the vibrating sieve 23. After valuable materials such as iron and aluminum are separated and recovered from the incombustible material having a large particle size by the valuable material recovery facility 26, the rest is disposed of in landfills. On the other hand, the fluid medium having a small particle diameter is conveyed vertically upward by the sand circulation elevator 24, returned to the fluidized bed gasification furnace 11 through the sand injection valve 25, and reused as the fluid medium.
[0025]
Since in the facility, is usually in the freeboard 11c of the gasification furnace is maintained at a negative pressure of about several tens mmH ₂ O, resulting in the vertical direction on the pressure loss of the fluidized bed and to fluidize the fluidized medium, the furnace The bottom 11a is operated at a positive pressure of about 1500 mmH ₂ O. For this reason, as a means for preventing the combustible gas in the gasification furnace from leaking into the atmosphere, the in-furnace chute 12 and / or the incombustible discharge device 21 is filled with a mixture of a fluid medium and incombustibles, so-called material. The seal is done. However, complete sealing with a material seal is impossible, and it is inevitable that a small amount of combustible gas leaks into the atmosphere.
[0026]
The mixed gas processing apparatus 1 includes a bag filter 1b as a dust removing device that is a means for removing dust from the mixed gas, and a blower 1a as a mixed gas suction means. The bag filter 1b is installed on the upstream side of the blower 1a. Further, in order to prevent leakage gas from the fluidized bed gasification furnace 11 from being discharged to the outside, a line 61 is connected to the upper part of the incombustible discharge device 21, and a line 62 is connected to the chute above the vibrating sieve 23, A suction port is provided above the sand circulation elevator 24, and a line 63 is connected to the suction port. The lines 61 to 63 merge with the line 64, and the line 64 is connected to the bag filter 1b.
[0027]
In this way, the combustible gas can be concentrated without leaking outside. Here, the place to be sucked is not clearly specified, and it is only necessary to achieve the purpose of preventing external leakage of the combustible gas. However, the vicinity of the incombustible discharge device 21 having the highest concentration of combustible gas is most effective and preferable. Further, in order to make the combustible gas out of the explosion limit by diluting with a large amount of air, the combustible gas is diluted and mixed gas by injecting air from the atmosphere through the valuable recovery device 26 and the vibration sieve 23. Is supplied to the bug filter 1b. The mixed gas is dedusted by the bag filter 1b and then guided to the blower 1a.
[0028]
Here, the amount of air to be introduced is preferably at least twice as much as the amount of flammable gas leakage, but more preferably at least five times. If it is twice or more, the external leakage of the combustible gas can be prevented almost certainly. If the amount of air is too small, the temperature of the mixed gas becomes high, the temperature of the combustible gas falls within the explosion limit range, and if there is an ignition source, there is a possibility of explosion. Therefore, it is necessary to suck a sufficient amount of the low-temperature atmosphere and dilute the combustible gas sufficiently. If it is 5 times or more, external leakage can be prevented more reliably.
[0029]
The mixed gas composed of the combustible gas and a large amount of air sucked by the blower 1 a is a secondary blower that sends air to the suction line 51 of the pusher blower 41 that supplies air to the gasification furnace 11 and the melting furnace 31 through the pipe 65. 42 is supplied to the suction line 53. The suction lines 51 and 53 suck air from the garbage pit. In this way, air containing bad odor in the pit is prevented from leaking to the outside.
The mixed gas is mixed with the air from the waste pits and then introduced into the gasification furnace or melting furnace 31. Thus, since the combustible gas leaked from the gasification furnace 11 is burned at a high temperature, even if organic harmful components are contained, these are completely oxidized and decomposed.
[0030]
In this figure, the pipe 65 is connected to the suction line 51 of the forced blower 41 that supplies air to the gasification furnace 11 and the suction line 53 of the secondary blower 42 that sends air to the melting furnace 31. You may connect to either one of the suction line 51 or the suction line 53 of the secondary air blower 42. Further, the gas may be supplied directly to the gasification furnace 11 and / or the melting furnace 31 without passing through the blowers 41 and 42. When the mixed gas is supplied to the melting furnace 31, the same effect can be expected regardless of whether it is supplied to any of the primary combustion chamber 31a, the secondary combustion chamber 31b, and the tertiary combustion chamber 31c constituting the melting furnace 31. .
[0031]
FIG. 2 shows a second embodiment. A double damper 22 as a mechanical sealing means is provided between the incombustible discharge device 21 and the vibration sieve 23, and a mixed gas composed of combustible gas and air is sucked from the upstream side of the vibration sieve 23 downstream of the double damper 22. (Line 62) is supplied to the bag filter 1b. In this case, suction from the incombustible discharge device 21 is not necessary. This is because when the double damper 22 with high sealing performance is used, the suction from the incombustible discharge device 21 (corresponding to the line 61 in FIG. 1) forcibly sucks the combustible gas in the gasification furnace 11. This is because it is not preferable. The other points are the same as in FIG.
[0032]
If a mechanical sealing means represented by a double damper is provided as the sealing means, the amount of flammable gas that leaks can be reduced, so that it can be said to be a method particularly suitable for treating waste with a high calorific value. This is because the concentration of the combustible component in the generated combustible gas is high.
The mechanical sealing means is not limited to a double damper, and a triple damper or a sealing means using a plurality of gate valves may be used.
[0033]
As described above, the gasification and melting system according to the embodiment of the present invention includes the combustible gas leaking through the incombustible discharge port of the fluidized bed gasification furnace constituting the gasification and melting system and the air sucked from the atmosphere. The mixed gas sucked by a blower constituting the processing apparatus is for treating mixed gas, the combustion air supplied to the fluidized bed gasification furnace, the combustion air supplied to the melting furnace, or the flow Since it is led directly to at least one of the bed gasification furnace and the melting furnace, the leaked combustible gas can be treated appropriately and effectively. Furthermore, since it passes through the high temperature combustion zone of the melting furnace, a trace amount of harmful components can be oxidatively decomposed.
[0034]
【The invention's effect】
As described above, according to the present invention, the combustion air supply means for supplying the mixed gas containing the combustible gas to at least one of the fluidized bed gasification furnace and the melting furnace, and the mixed gas to the combustion air supply means Since the mixed gas transporting means for transporting is provided, it is possible to provide a gasification and melting system that can reduce the amount of combustible gas that is dissipated into the atmosphere as much as possible and can appropriately process it.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a gasification melting system according to a first embodiment of the present invention.
FIG. 2 is a block diagram showing a gasification melting system according to a second embodiment of the present invention.
FIG. 3 is a block diagram showing a conventional fluidized bed gasification furnace including an exhaust treatment device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Mixed gas processing apparatus 1a Blower 1b Dust removal apparatus 11 Fluidized bed gasification furnace 12 Furnace chute 21 Incombustible material discharge apparatus 22 Double damper 23 Vibrating sieve 24 Sand circulation elevator 25 Sand injection valve 26 Valuables recovery apparatus 31 Melting furnace 31a Melting furnace Primary chamber 31b Melting furnace secondary chamber 31c Melting furnace tertiary chamber 41 Pressing blower 42 Secondary blower a Waste b Combustion air p supplied to gasification furnace Fluid medium

Claims (4)

In a gasification and melting system comprising a fluidized bed gasification furnace for gasifying waste and a melting furnace for melting and burning the product produced in the gasification furnace;
A non-combustible material discharging means for discharging the non-combustible material contained in the waste from the bottom of the gasification furnace together with a fluid medium while performing material sealing with the non-combustible material and the fluid medium ;
Means for separating the discharged incombustibles from the fluid medium;
Air that has passed through the means for separating combustible gas that leaks from the gasification furnace through the means for discharging incombustible material from the upper part on the outlet side of the means for discharging incombustible material or between the means for discharging incombustible material and the means for separating. And a mixed gas suction means sucked with a blower to make a mixed gas;
Combustion air supply means for supplying combustion air and the mixed gas to at least one of the gasification furnace and the melting furnace;
A mixed gas transporting means for transporting the mixed gas to the combustion air supply means;
Gasification melting system. In a gasification and melting system comprising a fluidized bed gasification furnace for gasifying waste and a melting furnace for melting and burning the product produced in the gasification furnace;
A non-combustible material discharging means for discharging the non-combustible material contained in the waste from the bottom of the gasification furnace together with a fluid medium while performing material sealing with the non-combustible material and the fluid medium ;
Means for separating the discharged incombustibles from the fluid medium;
Air that has passed through the means for separating combustible gas that leaks from the gasification furnace through the means for discharging incombustible material from the upper part on the outlet side of the means for discharging incombustible material or between the means for discharging incombustible material and the means for separating. And a mixed gas suction means sucked with a blower to make a mixed gas;
A mixed gas transfer means for transferring the mixed gas to at least one of the gasification furnace and the melting furnace;
Gasification melting system.   The gasification and melting system according to claim 1 or 2, further comprising means for removing dust from the mixed gas. The mixed gas suction means is a mixed gas suction means for sucking the combustible gas from between the incombustible discharge means and the separating means;
  Mechanical sealing means disposed between the incombustible discharge means and the separating means;
  The mixed gas suction means sucks the combustible gas from the downstream side of the mechanical seal means;
  The gasification melting system according to any one of claims 1 to 3.

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