JP6277935B2 - Waste gasification and melting equipment - Google Patents

Description

  The present invention relates to a waste melting apparatus for thermally decomposing and burning waste in a shaft furnace type waste gasification melting furnace and melting residual ash.

  As a technique for treating waste such as municipal waste and shredder dust, a waste melting process is known in which waste is pyrolyzed and burned to melt residual ash to form slag and discharge it.

  In this treatment method, the heat of combustion can be recovered by pyrolyzing and gasifying the waste, and the remaining ash must be melted and discharged as slag and then disposed of in landfills. It has the advantage that the volume can be reduced. There are several methods for such melting treatment, and a shaft furnace type waste gasification melting furnace having a vertical shape is widely used as one of the apparatuses for that purpose.

  This shaft furnace type waste gasification melting furnace, for example, burns coke deposited in the lower part of the furnace, throws the waste on this high temperature coke, pyrolyzes and partially oxidizes it to gasify It is a furnace that performs a process of melting residual ash to form slag (see Patent Document 1). Further, in this type of shaft furnace type waste gasification and melting furnace, coke and limestone as a component adjusting material for slag generated by combustion of waste are often introduced into the furnace as a subsidiary material ( (See Non-Patent Document 1, pages 3-4). Hereinafter, the shaft furnace type waste gasification melting furnace of Patent Document 1 and the auxiliary material supply device of Non-Patent Document 1 will be sequentially described.

<Shaft furnace type waste gasification melting furnace>
In the shaft furnace type waste gasification and melting furnace of Patent Document 1, the interior of the vertical cylindrical furnace body is roughly divided into three regions in the vertical (vertical) direction. That is, a high-temperature combustion zone having a coke bed with coke deposited at the lower part of the furnace is formed, a waste layer is formed on the high-temperature combustion zone, and a large space is freed above the waste layer in the upper part of the furnace. A board portion is formed.

  In such a waste gasification melting furnace, oxygen-containing gas is blown into the furnace in each of the three regions of the high-temperature combustion zone, the waste layer, and the free board portion. The main tuyere is provided in the high-temperature combustion zone at the lower part of the furnace, and oxygen-enriched air is blown into it. In the high-temperature combustion zone, the coke in the coke bed that has been thrown in is burned and the remaining ash is melted. It is a melting heat source. Further, the waste layer is provided with a sub tuyere, air is blown in, and the waste deposited and flowed gently, and the waste is thermally decomposed and partially oxidized. In addition, the free board part is provided with a three-stage tuyere, air is blown in, and a part of the pyrolysis gas (combustible gas) generated by pyrolyzing the waste is partially burned to bring the inside to a predetermined temperature. To maintain.

  As described above, the shaft furnace type waste gasification and melting furnace is a facility capable of performing both pyrolysis gasification treatment and melting treatment in one furnace as the waste falls in the furnace. The input waste is pyrolyzed to produce gas and ash. The coke in the coke floor is combusted by blowing oxygen-enriched air from the main tuyere to form a high-temperature combustion zone, and the ash content of the waste is melted to produce molten slag and molten metal. Limestone for adjusting the slag component is introduced together with coke as an auxiliary material, and the limestone works as an adjusting material that makes the properties of slag in which ash is melted preferable. Molten slag and molten metal drip the gap between the coke masses and reach the furnace bottom. The molten slag and molten metal are homogenized by the time they reach the furnace bottom, their properties are stabilized, and the molten slag and molten metal are discharged from a tap provided at the furnace bottom.

  The high-temperature gas generated by coke combustion in the high-temperature combustion zone heats the waste in the waste layer formed on the high-temperature combustion zone, and the waste is thermally decomposed by blowing air from the sub tuyere. The gas containing the combustible gas generated by the gas rises in the waste layer, passes through the free board portion, and is discharged from the discharge port provided in the upper portion of the furnace to the secondary combustion chamber outside the furnace. The gas contains a large amount of combustible gas and is combusted in the secondary combustion chamber, and heat is recovered by the boiler to generate steam, which is used for power generation and the like. Exhaust gas treatment, such as removing relatively coarse dust with a cyclone, cooling with a temperature reducing device, removing harmful gas by reaction with a hazardous substance remover, and removing dust with a dust collector And then released from the chimney to the atmosphere.

<Sub-material supply device>
Limestone as a component adjusting material for slag generated by the combustion of coke and waste is called a secondary material. In Non-Patent Document 1, the secondary material is put into a furnace by a secondary material supply device. In the auxiliary material supply apparatus shown in Non-Patent Document 1, after the coke receives coke and limestone from the coke bunker (hopper) and limestone bunker (hopper), the coke and limestone are heated to a high temperature gasification direct melting furnace (shaft). It is transported to the inlet provided in the upper part of the furnace-type waste gasification and melting furnace), and supplied into the furnace through this inlet. More specifically, as shown in FIG. 3 of the accompanying drawings, the auxiliary material supply device 50 of Non-Patent Document 1 includes a coke hopper 51 having a coke cutting feeder 51A at its lower part and a limestone hopper 52 having a limestone cutting feeder 52A at its lower part. The coke and limestone are supplied to the auxiliary material metering conveyor 53 through the chutes 51B and 52B provided below them. The auxiliary material weighing and supplying conveyor 53 is formed as a belt conveyor, and an auxiliary material conveying conveyor 54 having a bucket 54A is disposed at a lower position in the conveying direction (arrow A). The auxiliary material conveying conveyor 54 is connected to an inlet provided in the upper part of the high temperature gasification melting furnace.

  According to the auxiliary material supply device 50 of Non-Patent Document 1, coke and limestone are cut out from the coke hopper 51 and the limestone hopper 52 by the coke cutting feeder 51A and the limestone cutting feeder 52A such as an electromagnetic vibration feeder, and then the chute 51B. , 52B and then dropped to the auxiliary material weighing and supplying conveyor 53. The auxiliary material weighing and supplying conveyor 53 is a conveyor having weighing means such as a load cell, and measures and supplies the supply amount of coke and limestone. Coke and limestone are delivered from the auxiliary material metering conveyor 53 to the auxiliary material conveyor 54 and then brought to the inlet of the high temperature gasification direct melting furnace by the auxiliary material conveyor 54. To the high-temperature gasification direct melting furnace as an auxiliary material. From the coke hopper 51 and the limestone hopper 52, a predetermined amount of coke and limestone to be supplied next is cut out.

JP 09-060830 A JFE Engineering High-temperature gasification direct melting furnace Catalog 2003 Catalog No. CA3038 <http://www.jfe-eng.co.jp/products/environment/pdf/CA3038.pdf>

  However, in the secondary material supply apparatus of Non-Patent Document 1, the secondary material conveyance conveyor has two types of the secondary material weighing and supply conveyor and the secondary material conveyance conveyor located above and below, and both are substantially in series. Therefore, a large installation space, particularly in the transport direction, is required, and the entire facility cannot be made compact.

  Next, if the auxiliary material measurement and supply conveyor is in the form of a belt conveyor, the coke and limestone on the conveyor belt may not be completely delivered to the subsequent auxiliary material conveyance conveyor.

  Moreover, if the conveyance speed of the auxiliary material weighing and supplying conveyor is not an appropriate speed, delivery to the auxiliary material conveying conveyor is not performed smoothly, which may cause trouble.

  Furthermore, the conveyor belt may be bitten by the auxiliary material metering conveyor, and the conveyor belt may be bent and coke and limestone may be spilled.

  Furthermore, since the auxiliary material metering conveyor passes through the two stations of the limestone hopper and the coke hopper, the conveying length is relatively large, and it takes a long time for the conveying. Time was generated and operational efficiency was low.

  In view of such circumstances, an object of the present invention is to provide a waste gasification and melting device including a compact and efficient auxiliary material supply device.

A waste gasification and melting apparatus according to the present invention is a waste gasification and melting furnace of a shaft furnace type, and waste is pyrolyzed, gasified and burned by introducing waste into the furnace from the inlet at the top of the furnace, and remains. A waste gasification and melting device for melting ash content
An auxiliary material supply device is provided for supplying the auxiliary material to the waste gasification melting furnace from the input port.

In such a waste gasification and melting apparatus, in the present invention, the auxiliary material supply apparatus includes a coke hopper, a limestone hopper, and a mixing hopper, and the coke hopper and the limestone hopper are mixed below each chute. Connected to the mixing hopper so that coke and limestone flow into the hopper,
The mixing hopper has a metering discharge unit for metering and discharging a mixture of coke from the coke hopper and limestone from the limestone hopper,
Under the mixing hopper, there is provided an auxiliary material conveying conveyor for receiving the mixture from the metering discharge portion of the mixing hopper and conveying it to the charging port of the waste gasification melting furnace.

  In the present invention, the coke hopper is preferably provided with a coke cutting feeder at the bottom, and the limestone hopper is preferably provided with a limestone cutting feeder at the bottom.

  In the present invention having such a configuration, coke and limestone are supplied and supplied to the waste gasification and melting furnace as auxiliary materials in the following manner.

  Coke is transferred from the coke hopper of the auxiliary material supply device, and limestone is transferred from the limestone hopper to a common mixing hopper and stored therein. The coke hopper and limestone hopper outlet openings are set so that coke and limestone are fed to the mixing hopper at an appropriate ratio.

  The coke and limestone are mixed in the mixing hopper, and the mixture is weighed so that the mixture becomes a predetermined amount by the metering discharge portion of the mixing hopper, discharged by a predetermined amount, and supplied to the auxiliary material conveying conveyor located below. The mixture is fed into the furnace from the inlet of the waste gasification melting furnace by the auxiliary material conveyor.

  In the furnace, coke contributes to the combustion of waste and contributes to the formation of a coke bed in the lower part of the furnace, and limestone contributes to the adjustment of slag components after ash melting.

  In the present invention, as described above, the auxiliary material supply device is provided with the mixing hopper below the coke hopper and the limestone hopper, and the coke and limestone are mixed as a mixture by the mixing hopper and then supplied to the auxiliary material conveying conveyor. Therefore, it is no longer necessary to use a secondary material metering conveyor that is long in the direction of conveyance provided below the coke hopper and limestone hopper as in the past, and as a conveyor, the auxiliary material conveyance provided below the hopper Since only one conveyor is required, the equipment can be made compact in the transport direction by the amount that does not require a secondary material weighing and supplying conveyor. The problem can be avoided, and the mixture hopper can be used according to the operating conditions such as the conveyance speed of the auxiliary material conveyor. Since it is only necessary to perform metering discharge, the delivery of the mixture as a subsidiary material to the subsidiary material conveyor is ensured, and moreover, the waste gasification and melting furnace is charged by the amount not using the conventional subsidiary material metering conveyor. There is no waiting time on the auxiliary material transfer conveyor for transferring the auxiliary material to the mouth, and the transfer efficiency is increased.

It is a figure which shows the outline | summary structure of the waste gasification melting furnace in one Embodiment apparatus of this invention. It is a figure which shows the schematic structure of the auxiliary material supply apparatus for the apparatus of FIG. It is a figure which shows schematic structure of the conventional auxiliary material supply apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 and 2 of the accompanying drawings. The waste gasification and melting apparatus of the present embodiment includes a shaft furnace type waste gasification and melting furnace and a secondary material supply device that supplies coke and limestone as secondary materials to the waste gasification and melting furnace. Prior to the description of the waste gasification and melting apparatus, a schematic configuration of a shaft furnace type waste gasification and melting furnace used in the apparatus will be described.

<Outline configuration of waste gasification and melting furnace>
A shaft furnace type waste gasification and melting furnace 1 according to an embodiment of the present invention shown in FIG. 1 has a waste gasification and melting furnace 1 as an object to be treated and a fuel as a fuel in the upper part of the waste gasification and melting furnace 1. An inlet 2 is provided for introducing limestone as a component adjusting material for coke and generated slag into the furnace, and a gas outlet for exhausting the gas in the furnace to the outside on the upper side. 3 is provided. In addition, an outlet 4 for discharging molten slag and molten metal is provided at the bottom of the waste gasification melting furnace 1.

  Above the waste gasification and melting furnace 1, a waste supply device 7 and a secondary material supply device 20 are disposed for supplying coke and limestone as secondary materials together with waste such as municipal waste into the furnace. Waste, coke and limestone are fed into the furnace through the inlet 2 at the top of the furnace.

  A secondary combustion chamber 10 is connected to the gas discharge port 3 and combustible gas generated by pyrolyzing waste is combusted in the secondary combustion chamber 10. The secondary combustion chamber 10 is preferably provided with an air blowing port 11 for blowing air for secondary combustion. Further, the secondary combustion chamber 10 is provided with a boiler 12 adjacent to which heat is recovered from the combustion gas obtained by burning the combustible gas in the secondary combustion chamber 10.

  In such a shaft furnace type waste gasification and melting furnace 1, the internal space in the furnace is divided into four regions in the vertical direction, and from below, the coke packed bed A, the moving bed B, and the gasification bed C A free board portion D is formed.

  In the waste gasification and melting furnace 1, tuyere is provided in each of the coke packed bed A and the gasification layer C, and oxygen-containing gas is blown into the furnace. That is, the main tuyere 5 is provided in the coke packed bed A in the lower part of the furnace, and oxygen-enriched air is blown in. The gasification layer C is provided with a sub tuyere 6 and air is blown in.

  When coke is charged into the waste gasification and melting furnace 1 having the tuyere 5 and 6, the coke descends to the lower part of the furnace, and the coke is burned by the oxygen-enriched air blown from the main tuyere 5. The generated high-temperature combustion gas serves as a heat source for thermal decomposition of waste, and further serves as a heat source for melting ash.

  Air is blown into the gasification layer C from the sub tuyere 6, the waste is dried, and then pyrolyzed and partially oxidized to gasify the combustible component.

  Moreover, in the free board part D, a part of pyrolysis gas (flammable gas) produced by pyrolyzing the waste is partially burned to maintain the inside of the furnace at a predetermined temperature.

<Sub-material supply device>
The waste gasification and melting furnace 1 configured and functioning as described above includes a secondary material supply device 20 for appropriately supplying coke and limestone as secondary materials.

  As shown in FIG. 2, the auxiliary material supply device 20 includes a coke hopper 21 and a limestone hopper 22 that store coke and limestone as auxiliary materials, respectively, and a mixing hopper that receives coke and limestone from these hoppers and stores them as a mixture. 23, and further, there is an auxiliary material conveying conveyor 24 that receives the mixture and conveys it to the charging port 2 of the waste gasification melting furnace 1.

  The coke hopper 21 and the limestone hopper 22 have a coke cutting feeder 21 </ b> A and a limestone cutting feeder 22 </ b> A such as an electromagnetic vibration feeder, respectively, in the lower part thereof. The coke cutting feeder 21A and the limestone cutting feeder 22A are adjustable and set so that their cutting amounts are adjustable and the ratio of the coke and limestone cutting amounts is a predetermined value. The coke cutting feeder 21A and the limestone cutting feeder 22A only need to be able to change and set the cutting amount ratio to an appropriate value as described above, and need not have a function of measuring the cutting amount.

  The coke cutting feeder 21A and the limestone cutting feeder 22A are provided with a coke chute 21B and a limestone chute 22B extending downward, respectively.

  A mixing hopper 23 is provided below the coke hopper 21 and the limestone hopper 22 so as to receive both coke and limestone falling from the coke chute 21B and the limestone chute 22B and store them as a mixture of coke and limestone. It has become. The mixing hopper 23 has a weighing feeder 23A as a weighing discharge portion at a lower portion thereof, and a mixture chute 23B is suspended from the weighing feeder 23A. Thus, in the mixing hopper 23, a mixture in which coke and limestone are mixed at a predetermined ratio is weighed and discharged by a predetermined amount by the weighing feeder 23A. The measurement discharge timing and the measurement discharge amount can be appropriately changed and set.

  In this embodiment, the auxiliary material conveying conveyor provided below the mixing hopper 23 is formed as a bucket conveyor having buckets 24A, and the bucket 24A is configured to move the mixture chute 23B of the mixing hopper 23 in the conveying direction. It moves from the position immediately below to the position of the inlet 2 of the waste gasification melting furnace 1. The weighing feeder 23A or the mixture chute 23B of the mixing hopper 23 has an opening / closing valve, and the opening timing of the opening / closing valve is synchronized when the bucket 24A comes to the position of the mixture chute 23B.

  In the waste gasification and melting furnace apparatus according to this embodiment configured as described above, the waste gasification and melting treatment is performed in the following manner. The procedure will be described in the order of gasification and melting in the waste gasification and melting furnace and supply of the secondary material by the secondary material supply device.

<Gasification and melting in waste gasification and melting furnace>
Waste from the waste supply device 7, coke and limestone as auxiliary materials from the auxiliary material supply device 20 pass through the inlet 2 provided in the upper part of the waste gasification melting furnace 1, and each in a predetermined amount. Then, oxygen-enriched air is blown from the main tuyere 5 and air is blown from the sub tuyere 6 into the furnace. From the main tuyere 5, oxygen-enriched air is blown into the coke packed bed A.

  The coke put into the furnace descends to the lower part of the furnace, and the coke is burned by the oxygen-enriched air blown from the main tuyere 5 to provide a heat source for melting waste ash, and the generated high-temperature combustion gas Provides a heat source that heats up and heats up for the pyrolysis of waste and forms a coke bed.

  Waste introduced from the inlet 2 accumulates in the furnace to form a gasification layer C of the waste, and passes through the moving bed B from the coke packed bed A at the lower part of the furnace and rises at high temperature. It is heated by gas and air blown from the sub tuyere 6, dried and then pyrolyzed. Combustion gas containing combustible gas generated by pyrolysis rises, a part of the combustible gas is combusted in freeboard part D, maintains the inside of the furnace at a predetermined temperature, and harmful substances and tar generated by pyrolysis It is used so that the process which decomposes | disassembles a part may be given. The gas that has passed through the freeboard part D is discharged from the discharge port 3 provided in the upper part of the furnace to the secondary combustion chamber 10 outside the furnace. The gas contains a large amount of combustible gas and is combusted in the secondary combustion chamber 10, and heat is recovered by the boiler 12 to generate steam, which is used for power generation and the like. The gas discharged from the boiler 12 has relatively coarse dust removed by a cyclone (not shown), further cooled by a temperature reducing device (not shown), and removed by reaction with a hazardous substance remover. Then, after exhaust gas treatment such as dust removal with a dust collector (not shown), it is emitted from the chimney (not shown) to the atmosphere.

The waste is thermally decomposed in the gasification layer C to generate gas, and the fixed carbon and ash generated by the thermal decomposition descend together with the coke and limestone to form the moving layer B. In the moving bed B, the temperature of the solid descending is increased by the high temperature gas rising from the coke packed bed A, and at the same time, the fixed carbon generated by the thermal decomposition of the waste is gasified by the high temperature CO ₂ gas. The In the coke packed bed A, the oxygen-enriched air blown from the main tuyere 5 burns the coke and the fixed carbon of the waste that remains without being gasified, and the heat of combustion melts the ash content of the waste, Molten metal is produced. Limestone charged into the furnace as the auxiliary material from the charging port 2 serves as an adjusting material that makes the slag melted with ash preferable. Further, the generated high-temperature combustion gas rises and becomes a heat source for heating for thermal decomposition of the waste.

  In the lower part of the furnace below the main tuyere 5, coke packed bed A is formed in a state in which coke which is high in temperature but not burned out is filled while maintaining a gap between the coke lumps. Molten slag and molten metal Drops the gap between coke lumps and reaches the bottom of the furnace. The molten slag and molten metal are homogenized by the time they reach the bottom of the furnace, their properties are stabilized, discharged from the tap 4 provided at the bottom of the furnace, and supplied to a water granulator (not shown) provided outside the furnace. The supplied granulated slag and granulated metal are recovered by cooling and solidifying. The oxygen-enriched air blown from the main tuyere 5 and the high-temperature combustion gas generated by the combustion of coke and fixed carbon pass from the coke packed bed A through the moving bed B to the gasified bed C and are discarded. A thing is heated and the waste of the gasification layer C is partially oxidized and thermally decomposed by the air supplied from the sub tuyere. In the coke packed bed A, the coke burns to become a heat source for ash melting and waste pyrolysis, and the coke keeps the gaps between the lumps and ventilates the oxygen-enriched air and the high-temperature combustion gas to melt the molten slag and melt It has the function of a high-temperature grate that allows metal to pass through.

<Supply of secondary materials by secondary material supply device>
Coke and limestone as auxiliary materials by the auxiliary material supply device 20 are supplied to the waste gasification and melting furnace 1 as a mixture in the following manner by a predetermined amount ratio.

  Depending on the type and amount of waste to be supplied to the waste gasification and melting furnace 1, the supply conditions of the respective amounts and ratios of coke and limestone as auxiliary materials are set.

  The cutting amounts of the coke cutting feeder 21A and the limestone cutting feeder 22A of the coke hopper 21 are set so that the cutting amount matches the supply condition. Under this cutting amount, coke and limestone are cut out and supplied to the mixing hopper 23 and stored so as to form a mixture through the coke chute 21B and the limestone chute 22B. The mixture is cut out by a predetermined amount by the weighing feeder 23A, and the auxiliary material conveying conveyor which is waiting and stopped immediately below the mixture chute 23B by using an on-off valve provided on the weighing feeder 23A or the mixture chute 23B. The mixture is dropped and supplied to 24 buckets 24A. The bucket 24A is moved to the position of the charging port 2 of the waste gasification and melting furnace 1 by the operation of the auxiliary material conveying conveyor 24, and the mixture is charged into the furnace through the charging port 2.

  Since such a secondary material supply device 20 is used, it is not necessary to use a conventional secondary material metering and supply conveyor that is long in the conveyance direction, so that the equipment is compact in the same direction and the standby of the subsequent secondary material conveyance conveyor is maintained. Compared to conventional devices, such as time is lost and transport efficiency is improved.

DESCRIPTION OF SYMBOLS 1 Waste gasification melting furnace 2 Input port 20 Secondary material supply apparatus 21 Coke hopper 21A Coke cutting feeder 21B Coke chute 22 Limestone hopper 22A Limestone cutting feeder 22B Limestone chute 23 Mixing hopper 23A Metering discharge part (measuring feeder)
24 Sub-material conveyor

Claims (2)

A waste gasification and melting device that heats, decomposes, gasifies, and burns waste into a shaft furnace type waste gasification and melting furnace through the inlet at the top of the furnace and melts the remaining ash There,
In a waste gasification and melting apparatus equipped with a secondary material supply device that supplies secondary material to the waste gasification and melting furnace from the above-mentioned inlet,
The auxiliary material supply device includes a coke hopper, a limestone hopper, and a mixing hopper, and the coke hopper and the limestone hopper pass through their respective chutes so that the coke and limestone flow into the mixing hopper located below. Connected to
The mixing hopper has a metering discharge unit for metering and discharging a mixture of coke from the coke hopper and limestone from the limestone hopper,
Waste material, characterized in that a sub-material conveying conveyor is provided below the mixing hopper, which receives the mixture from the metering discharge section of the mixing hopper and conveys the mixture to the inlet of the waste gasification melting furnace. Gasification and melting equipment.   The waste gasification and melting apparatus according to claim 1, wherein the coke hopper is provided with a coke cutting feeder at a lower portion, and the limestone hopper is provided with a limestone cutting feeder at a lower portion.

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