JPH11118124A - Fluidized gassifying/melting apparatus, and method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the function of a fluidized bed gassifying/melting system for a combustible substance contained in various wastes such as municipal waste and/or industrial waste, and hence ensure stable operation. SOLUTION: Gas produced by thermally decomposing waste in a fluidized bed gassifying furnace 2 using a fluid medium is combusted in a combustion furnace 45, and resulting combustion gas is used to heat exchange with a heat exchange medium in an independent superheater 26, and then recirculation gas 19 after the heat exchange is used as a fluidizing fluid 13 of the fluid medium in the fluidized bed gassifying furnace 2. Thus, single operation is ensured in a state where the fluidized bed gassifying furnace 2 is separated from a melting furnace 4 and a heat recovery apparatus 5, and even when the operation of the fluidized bed gassifying furnace 2 or the succeeding melting furnace 4, etc., are interrupted for the purpose of maintenance or failure, the system including a fluidized bed gassifying furnace 2 system and the system including the melting furnace 4 and the heat recovery apparatus 5 are ensured to be single operated (warm-up operation). Thus, there is ensured a desirable state of the fluidized bed gassifying furnace 2 and the melting furnace 4 where temperature lowering due to the operation interruption should be avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluidized bed gasification and melting method for combustibles contained in municipal solid waste and / or various wastes using a fluidized bed.

[0002]

2. Description of the Related Art Various methods of treating municipal solid waste and various types of waste (hereinafter, simply referred to as garbage in the present invention) have been developed. Is pyrolyzed and ash is melted using the generated pyrolysis gas or char as a heat source. As one of the methods, there is a gasification and melting system in which combustibles contained in refuse are gasified by a fluidized-bed gasifier, and ash is melted and solidified.

In the above gasification and melting system, refuse supplied to a fluidized-bed gasification furnace is blown while being mixed with a fluidization medium such as sand and fluidized using a fluidization fluid such as air. It reacts with air and is gasified in a reducing atmosphere, producing flammable pyrolysis gas and solid char. Then, all of the obtained pyrolysis gas is burned in a pyrolysis gas combustion furnace and introduced into an exhaust heat recovery device. In addition, incombustibles (residues from the bottom of the combustion furnace) such as metals and debris in the garbage are contained in the char or separated from the char by utilizing the difference in physical properties such as particle size and specific gravity. After the metals in the incombustibles are recovered, the ash is used for landfilling or the like after being melted and solidified or as it is. The combustible gas, char and fly ash are sent to the ash melting furnace located on the downstream side of the fluidized bed gasifier to be used as a heat source, and most of the incombustibles such as fly ash are melted. You. The gas after these treatments are purified by the exhaust gas purification device,
Released into the atmosphere.

[0004]

In the prior art fluidized bed gasification and melting system, a combustion furnace for pyrolysis gas, a melting furnace, an exhaust heat recovery device and an exhaust gas are provided downstream of the fluidized bed gasification furnace. Since a purification device is provided, the fluidized fluid for the fluidized bed gasification furnace is used when the gasification and melting system is started or when the system is restarted after maintenance of each device that composes the melting furnace and the like. It is not possible to obtain a predetermined temperature until the whole system is warmed up and a steady state is reached, so that a fluidized bed gasifier cannot be started up quickly. That is, there is a disadvantage that it takes a long time to start up the entire system.

In addition, since a portion of a refuse pyrolyzer including a fluidized-bed gasifier and a portion including a subsequent heat recovery device including a melting furnace are systematically interconnected, each is operated independently. Can not do. That is, when the operation is stopped in any of these parts for maintenance or due to a failure or the like, it is necessary to completely stop the entire system. The fluidized-bed gasification furnace is filled with a fluid medium consisting of a large amount of sand and the like in a high temperature state, and the melting furnace is operated as much as possible (warm air operation Is desirable, but there is a disadvantage that the fluidized bed gasification melting system of the prior art is extremely difficult.

[0006] Furthermore, municipal solid waste and various industrial wastes that are put into a fluidized-bed gasifier contain chlorine and various heavy metals (the heavy metals can be catalytic elements that accelerate the corrosion of equipment). As a result, the chlorine and the like may accompany the pyrolysis gas and corrode components of the heat recovery unit. Therefore, high-temperature superheated steam cannot be obtained,
Therefore, high-efficiency power generation could not be realized using this fluidized-bed gasification and melting system.

In addition, combustibles such as refuse introduced into the fluidized-bed gasification and melting system are not uniform in properties, and the amount charged into the gasification furnace may fluctuate greatly with the passage of time. It was difficult to maintain the fluidized bed combustion. In particular, not only fluctuations in the amount of refuse, but also fluctuations in the water content of the refuse, the amount of auxiliary fuel supplied rapidly increases when refuse with a large amount of water is thrown into the gasifier in large quantities at once. Otherwise, fluidized bed gasification combustion may not be maintained.

An object of the present invention is to improve the function of a fluidized-bed gasification and melting system for combustibles contained in various kinds of wastes such as municipal solid waste and / or industrial wastes, to enable a stable operation, and to achieve a high operation efficiency. It is to realize efficient power generation.

Another object of the present invention is to enable quick start-up at the time of start-up, and to perform partial operation of some devices in a fluidized-bed gasification treatment system at the time of maintenance or at the time of failure of some devices. Is to make it possible. Another object of the present invention is to make it possible to quantitatively and quantitatively and quantitatively and quantitatively inject a refuse having a large quantity or property into a fluidized bed gasification furnace.

[0010]

The object of the present invention is solved by the following constitution. (1) A fluidized-bed gasifier for pyrolyzing and gasifying combustibles containing solids using a fluidized medium, and a melting furnace for melting solids such as fly ash obtained by pyrolyzing and gasifying the combustibles. Fluidized bed gasification comprising a heat recovery device that recovers heat using hot gas obtained in a fluidized bed gasification furnace system and / or a melting furnace, and an exhaust gas purification device that purifies exhaust gas discharged from at least one of the above devices. In the melting device, a pyrolysis gas combustion furnace that burns pyrolysis gas generated in a fluidized bed gasification furnace, an independent heat exchanger that performs heat exchange using combustion gas from the combustion furnace, and an independent heat exchanger A fluidized-bed gasification / melting apparatus comprising a gas circulation system including a recirculation gas flow path in which the combustion gas after heat exchange is used as a fluidization fluid of a fluidized-bed gasification furnace.

(2) In addition to the above configuration, a char entrained by the pyrolysis gas generated by the fluidized-bed gasification furnace provided in the gas flow path between the fluidized-bed gasification furnace and the pyrolysis-gas combustion furnace is provided. A fluidized bed gasification / melting apparatus comprising a separator for separating pyrolysis gas and a char storage tank for storing the char separated by the separator.

(3) A fluidized bed gasifier for pyrolyzing and gasifying combustibles containing solids using a fluidized medium, and a melting furnace for melting solids obtained by pyrolyzing and gasifying the combustibles and fluidizing A fluidized bed gasification / melting device comprising a heat recovery device for recovering heat using a hot gas obtained in a bed gasification furnace and / or a melting furnace, and an exhaust gas purification device for purifying exhaust gas discharged from at least one of the above devices. 3. The fluidized-bed gasification and melting apparatus according to claim 1, further comprising a pretreatment device for supplying a solid combustible to a fluidized-bed gasification furnace while leveling the thickness of the combustible by reciprocating motion of a plurality of movable plates.

(4) Pyrolytic gasification of a combustible material including a solid substance in a fluidized bed gasifier using a fluidized medium, and recovering heat in a heat recovery medium using a pyrolyzed gas obtained as a heat source, and recovering the combustible material. In a fluidized-bed gasification and melting method in which a solid content obtained by pyrolysis gasification is melted, a pyrolysis gas generated in a fluidized-bed gasification furnace is burned, and heat from the combustion heat of the combustion gas is transferred to a heat recovery medium. A fluidized-bed gasification / melting method in which after the exchange, the combustion gas after the heat exchange is used as a fluidizing fluid of a fluidized medium of a fluidized-bed gasifier.

(5) Pyrolytic gasification of a combustible material including a solid substance in a fluidized-bed gasification furnace using a fluidized medium, and recovering heat in a heat recovery medium using a pyrolysis gas obtained as a heat source; In the fluidized-bed gasification melting method of melting the solids obtained by pyrolyzing and gasifying the combustible material, the combustible material is dried while the layer thickness is leveled, and the combustible material has a substantially uniform thickness and moisture content. Fluidized-bed gasification and melting method in which materials are sequentially supplied to a fluidized-bed gasification furnace.

Thus, according to the present invention, the flammable pyrolysis gas generated in the fluidized bed gasifier is burned in the pyrolysis gas combustion furnace, introduced into an independent heat exchanger such as an independent superheater, and completely burned. . The combustion gas recovered by heat in an independent heat exchanger such as an independent superheater is recycled as a fluidizing fluid in a fluidized-bed gasification furnace. With this configuration, it is possible to completely start up the fluidized-bed gasification furnace or to continue the operation, completely separated from the operation of the downstream melting furnace and the exhaust heat recovery unit.

According to the present invention, since the fluidized bed gasifier can be operated independently in a state of being separated from the melting furnace and the heat recovery apparatus, the maintenance can be performed during maintenance of the fluidized bed gasifier or the subsequent melting furnace. Or, when these are stopped due to troubles, it is possible to continue the operation (warm-up operation) of each of the gas circulation system including the fluidized bed gasification furnace, the solid content and the gas treatment system including the melting furnace and the heat recovery unit independently. Become. This can provide a desirable condition in a gas circulation system including a fluidized-bed gasifier and a solids and gas processing system including a melting furnace and a heat recovery unit, in which it is desired to avoid a temperature decrease due to a shutdown as much as possible.

Further, when the gasification and melting furnace of the present invention is started, when the amount of pyrolysis gas is small or at low temperature, the air-fuel ratio of the fluidized-bed gasification furnace is adjusted by adjusting the combustion amount of the auxiliary fuel in the independent heat exchanger. Since it is easy to meet the predetermined conditions, the fluidized-bed gasifier can be quickly started.
In addition, a desalinating agent such as slaked lime is supplied to the fluidized bed gasifier,
By maintaining appropriate garbage pyrolysis conditions, that is, maintaining the temperature of the fluidized bed in the fluidized bed gasifier at 500 to 700 ° C, chlorine contained in the garbage and generated hydrogen chloride are reduced to calcium in slaked lime and ash. And the pyrolysis gas becomes a clean gas with a low hydrogen chloride content.

Further, in the present invention, when a solids separator such as a cyclone is provided in the gas flow path on the downstream side of the fluidized bed gasifier, char, ash, reaction products (such as calcium chloride) are provided in the separator. And the heavy metals and the like are separated from the gas components, and the reaction is promoted in the separator, so that the hydrogen chloride gas content can be further reduced. At this time, a desalinating agent such as slaked lime may be supplied into the separator.

By circulating the clean gas to various devices constituting the gasification and melting apparatus of the present invention, these chlorides which adversely affect the operation of the gasification and melting apparatus of the present invention, including the fluidized bed gasifier, are used. Concentration and accumulation of hydrogen and heavy metal components are eliminated, and there is an effect on maintenance and maintenance of the gasification and melting equipment.

In particular, since a clean pyrolysis gas containing a small amount of chlorine, which causes high-temperature corrosion of the superheater, can be supplied to the independent superheater, high-temperature, high-pressure steam can be recovered by the independent superheater, and high-efficiency power generation can be realized. . In addition, a combustion furnace for clean pyrolysis gas with low chlorine content obtained from a fluidized-bed gasification furnace was placed in front of the independent superheater, which is a typical example of an independent heat exchanger, and its combustion was stabilized by controlling its combustion. High-temperature steam (about 500 ° C.) can be easily obtained, and high-efficiency power generation can be achieved.

The waste before being put into the fluidized bed gasifier is put into a pretreatment device such as a great dryer.
At that time, the height of the piled-up debris is averaged by a pre-treatment device such as a great dryer, and can be discharged uniformly from the discharge port. Supply becomes easy. At the same time, refuse having a uniform moisture content is uniformly and sequentially introduced into the fluidized-bed gasification furnace, so that there is an advantage that it is not necessary to use an auxiliary fuel for refuse combustion in the fluidized bed in the gasification furnace.

Further, at this time, at least one of the gasification and melting apparatuses of the present invention, such as a fluidized bed gasification furnace, a melting furnace, a heat recovery apparatus, or an independent heat source, is used as a waste drying fluid to be introduced into the pretreatment apparatus. By introducing preheated air or hot gas obtained from an exchanger or the like, and further guiding the fluid after drying the waste discharged from the pretreatment device to at least any one of the gasification and melting devices of the present invention, for drying the waste. The amount of the fluid discharged outside the system of the gasification and melting apparatus can be reduced.

As the fluid after the refuse is dried, a part of the preheated air used in the gasification furnace is used, or a hot gas discharged from an independent heat exchanger or a heat recovery device is used. When the preheated air is used for refuse drying, after the refuse is dried, it is supplied to a fluidized bed gasifier, a melting furnace, and a pyrolysis gas combustion furnace, and the refuse is dried for hot gas discharged from an independent heat exchanger or a heat recovery device. When used for wastewater, after the refuse is dried, it is supplied to a fluidized bed gasifier or a heat recovery unit. In addition, the burden of purifying the odor-removed refuse-dried fluid at the time of discharge to the atmosphere is reduced, and at the same time, even if the refuse-drying fluid leaks, it is still the system of the gasification and melting apparatus of the present invention. Therefore, no trouble occurs in the post-processing.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic flow of the gasification and melting system of the present embodiment, and the outline of this flow will be described. Municipal refuse and / or various wastes (hereinafter, sometimes referred to as refuse) supplied from the pretreatment facility 1 to the fluidized bed gasifier 2 are burned and separated into solids and pyrolysis gas. After the solid content such as char accompanying the pyrolysis gas is separated from the pyrolysis gas by a separator such as a cyclone separator 25, the solid content is burned in a combustion furnace 45 in front of an independent superheater 26 which is a feature of the present invention. Is recovered by an independent superheater 26 into superheated steam. On the other hand, the ash and char in the solid content obtained in the fluidized-bed gasification furnace 2 are sent to the melting furnace 4 via the separation facility 3, and at the same time, the heat from the fluidized-bed gasification furnace 2 is supplied to the melting furnace 4. The cracked gas and solids such as char entrained by the pyrolyzed gas are also supplied, and the ash in the solids obtained from the refuse is melted. The hot gas obtained in the melting furnace is used for heat exchange of fluid in the superheater 6, the evaporator 7, the air preheater 8 and the economizer 9 in the secondary combustion furnace 5, and then purified by the exhaust gas treatment device 10. It is processed and released from the chimney 31 into the atmosphere.

In FIG. 1, crushed refuse 11 is introduced from a pretreatment facility 1 having a drying function and the like into a fluidized bed gasification furnace 2 from an introduction section 12 via a constant-rate feeder 32. Under the condition that the air-fuel ratio is about 0.3 in the fluidized bed gasifier 2, the crushed waste 11 is thermally decomposed by the fluidizing fluid 13, and the pyrolysis gas and the char are separated from the top of the fluidized bed gasifier 2 It is taken out as pyrolysis gas 15. The pyrolysis gas 15 containing no char varies depending on the composition of the refuse and the like, but the following components and their content ratio (% by weight) are shown in an example where slaked lime described below is not added into the gasification furnace 2. And its calorific value was 1,066 kcal / kg. _{CO 12.4; CH 4 8.4; N} 2 22.7; H 2 O 50.2; CO 2 6.2; Cl 2 200ppm

Further, combustion residues such as metals, incombustibles, and chars (also referred to as furnace bottoms) are discharged from the furnace bottom of the gasification furnace 2 by a noncombustibles / char extracting device 33, and separated by a separation facility 3.
Resources 14 such as metals and ash-char mixture 16
Is separated into The pyrolysis gas 15 generated in the fluidized-bed gasification furnace 2 is sent to a cyclone separator 25, which converts the pyrolysis gas 15 into a gas component composed of the pyrolysis gas 15 and a solid component composed of ash and char accompanying the pyrolysis gas 15. Separated. The gas component separated by the cyclone separator 25 is burned in a combustion furnace 45 provided in a stage preceding the independent superheater 26. In the combustion furnace 45, only the pyrolytic gas and char having high combustibility are burned.
A 200 ° C. hot gas is obtained. However, if necessary at the time of starting the gasification and melting system, the auxiliary fuel 17 using kerosene, propane gas, or the like may be added and burned. Then, this combustion heat is supplied into the superheater 26, and is used for superheating the steam at about 250 to 300 ° C in the superheater 26, so that superheated steam at about 500 ° C can be obtained. This steam is used for a steam turbine (not shown).

About 400 to 4 used in the independent superheater 26
A part of the combustion gas 23 at 50 ° C. is used as the recirculation gas 19 and merges with the high-temperature air 24 supplied to the gasification furnace 2 to become the fluidized fluid 13 of the mixture of the fluidized medium and the refuse. The pressure of the recirculated gas 19 used as the gas to be recirculated to the fluidized bed gasifier 2 needs to be increased to a pressure higher than the pressure required for the fluidized fluid 13. Is done. Thus, the recirculated gas 19
It is necessary to increase the pressure above the pressure required as the fluidizing fluid 13 used in the gasification furnace 2, but the pressure of the pyrolysis gas 15 may be increased instead of the recirculation gas 19.

Pyrolysis gas 1 in cyclone separator 25
Char separated from 5 is a char service hopper 34
Once stored. Also, from the bottom of the gasifier 2,
The incombustibles and the char are extracted through a flow path composed of a water-cooled jacket, for example, by an extracting device 33 composed of a screw conveyor or the like. By the method 3, the material 14 is separated into a recyclable material 14 such as a metal or a metal product and a mixture 16 of ash and char by, for example, particle size or specific gravity difference. Then, the mixture 16 of ash and char is also supplied to the char service hopper 34. The combustion residue of the combustion furnace 45 is also supplied from the furnace bottom of the independent superheater 26. When a fluid medium (such as sand) is contained in the mixture 16 of ash and char, the mixture may be appropriately separated and returned to the gasification furnace 2. The transport of these solids is performed by airflow transport using an inert gas or the like.

The mixture 16 of ash and char is sent from the char service hopper 34 to the melting furnace 4. In the melting furnace 4,
Approximately 1400 to 1400 depending on the char supplied from the char service hopper 34 and the heat of combustion of the auxiliary fuel 17 as necessary.
At 1500 ° C. the ash is melted. Further, a part of the gas components separated by the cyclone separator 25 is also supplied to the melting furnace 4 and serves as a heat source for melting the ash. Further, the molten slag 18 from the melting furnace 4 flows down to a water tank 21 of a water cooling system and is collected as granulated slag 40.

The hot gas of about 1400 to 1500 ° C. obtained by melting the ash in the melting furnace 4 is cooled by the water cooling wall of the secondary combustion furnace 5 to about 1100 ° C., and the superheater 6, the evaporator 7, the air preheating It is used for heating the vessel 8 and the economizer 9.
Further, by setting the air-fuel ratio in the secondary combustion furnace 5 to about 1.3, the secondary combustion furnace 5 including the gas from the melting furnace 4 can be used.
The gas components are completely burned inside.

Air at a normal temperature is supplied to the air preheater 8 from the air blower 28 and the air preheater 8
The air at 400 ° C. is used as combustion air for pyrolysis gas, char and auxiliary fuel 17 in the independent superheater 26, and air sent to the diffuser 22 of the fluidized bed gasifier 2. Further, the ash in the scattered gas is collected at the bottom portion on the most downstream side of the secondary combustion furnace 5, and the collected fly ash is pushed into the melting furnace 4 by a blower or compressed air by a compressor 38. And melted again.

The ash and char mixture 16 or the melting furnace 4
If a desalinating agent such as slaked lime is charged in the tank, chlorine contained in the ash and the like is removed. The gas discharged from the secondary combustion furnace 5 is sent to an exhaust gas treatment facility 10. Although not shown in the exhaust gas treatment equipment 10, since a cooling tower, a back filter, a denitration catalyst tower, an activated carbon tower, and the like are arranged, the exhaust gas treatment equipment 10 allows the exhaust gas The gas is cooled to about 150 ° C. to increase the dust collection efficiency at the bag filter, and then subjected to denitration. Further, dioxin generated by the chlorine component is almost completely suppressed in the melting furnace 4 and the secondary combustion furnace 5 under a high-temperature atmosphere, but between the outlet of the furnace and the gas treatment equipment 10, Dioxin to be resynthesized is removed by a bag filter, and traces of remaining dioxin and heavy metal components are removed by a denitration catalyst tower or an activated carbon tower.

From the exhaust gas treatment equipment 10 to the chemical treatment device 36
The combustion fly ash is discharged, and the chemical treatment device 36 prevents the elution of heavy metals by chelating and immobilizing treatment, renders it harmless, and performs landfill treatment. In addition, exhaust gas treatment equipment 10
The purified gas component discharged from the air is sent to the chimney 31 by the induction ventilator 30 and discharged to the atmosphere. In FIG. 1, the combustion fly ash 20 collected in the exhaust gas treatment facility 10 is to be used for landfill after being treated in the chemical treatment tank 36, but this may be returned to the melting furnace 4. . Further, a passage opening / closing valve 44 is provided in each fluid passage of FIG. FIG. 1 shows an example of a melting furnace 4 for melting ash by burning char or the like. Instead of the melting furnace 4, another combustion furnace, a hot blast furnace or a heating furnace may be individually arranged. .

The present invention is characterized in that a desalinating agent such as slaked lime is added from the empty tower in the fluidized-bed gasification furnace 2, and the slaked lime contained in the litter and the like is expressed by the following formula (1). The component can be immobilized as calcium chloride. Ca (OH) ₂ + HCl → CaCl ₂ + 2H ₂ O (1) Since this reaction proceeds at an optimum temperature of 500 to 700 ° C.,
The temperature inside the fluidized-bed gasification furnace 3 is adjusted to be within this temperature range. This temperature adjustment is performed by controlling the supply amount of the preheated air 24 from the air diffuser 22 and the amount of the recirculated gas 19 mixed with the preheated air 24.

As described above, since the chlorine concentration in the composition of the pyrolysis gas is about 200 ppm, about 3 to 5 mol of a desalinating agent such as slaked lime is added to the fluidized bed with respect to hydrogen chloride generated from the chlorine component. It is added into the gasification furnace 2. Here, in place of the slaked lime, other desalting agents, for example, quicklime, magnesium hydroxide, caustic soda, potassium and the like may be used.

The pyrolysis gas 15 and the scattered char generated in the fluidized bed gasifier 2 are supplied to the cyclone separator 25 from the top of the gasifier 2. The process proceeds even from the furnace 2 to the cyclone separator 25. Since the pyrolysis gas 15 contains an alkali component (calcium, sodium, potassium, etc.), the desalination reaction proceeds not only with the calcium component from slaked lime added as the desalting agent but also with the alkali component. In particular, since the pyrolysis gas 15 is agitated in the cyclone separator 25, the contact efficiency between the alkali component entrained in the pyrolysis gas 15 and the chlorine component generated from dust and the like is good, and the reaction of the above formula (1) The reaction between the alkali component and the chlorine component similar to the above is effectively performed. According to the measured values, the concentration of hydrogen chloride in the gas at the inlet of the cyclone separator 25 was 200 ppm, but the concentration in the gas at the outlet of the cyclone separator 25 was reduced to 50 ppm.

Further, since the pyrolysis gas 15 and the ash / char mixture 16 are separated by the cyclone separator 25, chlorine is easily fixed to the ash / char mixture 16. Since the chlorine content in the gas 15 is further reduced, the effect of preventing the high temperature corrosion of the independent superheater 26 is effective. Note that a desalinating agent such as slaked lime may be added to the cyclone separator 25.

When the concentration of hydrogen chloride in the pyrolysis gas 15 is 50 p
When the pressure is about pm, the corrosiveness of the gas 15 hardly matters. Therefore, the pyrolysis gas 15 is used as a fuel source and burned in a combustion furnace 45 provided in a stage preceding the independent superheater 26 to generate a hot gas of about 1100 to 1200 ° C. Is heated,
Since there is almost no chlorine component, the heat transfer tube of the independent superheater 26 is not likely to be corroded.

When combustibles contained in conventional refuse and the like are burned, the concentration of hydrogen chloride in the obtained combustion gas increases.
Since high-temperature gas with high hydrogen chloride concentration is highly corrosive, even if it is used for heating the superheater, only superheated steam of at most 400 ° C. is obtained, and therefore, a sufficiently superheated steam for a steam turbine is supplied. I couldn't do that. But,
According to the present invention, a hot gas free from high-temperature corrosion can be obtained by the above-described desalting treatment by the fluidized-bed gasification furnace 2 and the cyclone separator 25. Further, by burning in the combustion furnace 45 using the high-temperature hot gas thus obtained, a high-temperature superheated steam of about 500 ° C. can be obtained from the independent superheater 26 immediately after the cyclone separator 25.

After the superheated steam is heated by the independent superheater 26, the hot gas 23 at about 450 ° C. passes through a recirculation gas passage provided with a recirculation pump 35, and is converted into a recirculated gas 19 by fluidized bed gasification. The gas is supplied to the diffuser 22 of the furnace 2 and used as the fluidizing fluid 13. Thus, the fluidized fluid 13 in the fluidized bed gasifier 2 is generally recirculated to the high temperature (about 350 to 400 ° C.) air 24 heated by the air preheater 8 or a suitable temperature range (about 450 ° C. or less). The gas 19 is recycled and used alone or as a mixture.

As shown in FIG. 4, the independent superheater 26 detects the steam temperature in the steam pipe 51 at the outlet of the independent superheater 26 with a thermometer 52a and a steam flow rate with a flow meter 52b. A controller 56 is provided at the connection between the supply amount of the pyrolysis gas 15 and the heat transfer tube 52 of the independent superheater 26 so that the temperature is maintained at a constant temperature regardless of the variation in the property and supply amount of the refuse. The adjustment of the supply amount of the cooling water 55 to the temperature reducer 53 is controlled by the respective on-off valves 57,
Step 8 In this manner, the amount of superheated steam obtained in the independent superheater 26 can be stabilized, and drive control of a steam turbine (not shown) is facilitated. Further, in the present invention, equipment for fluid heating such as an air preheater and a water heater can be installed instead of the independent superheater 26 shown in FIG.

The pretreatment device 1 is a great drying device, and its detailed view is shown in FIG. FIG. 5A is a longitudinal sectional view of the pretreatment device 1, and FIG.
It is a figure showing the accumulation situation of the garbage seen from the direction of A. A waste inlet 1a is provided at one end of the ceiling of the pretreatment device 1, a casing 1c provided with a heat insulating material provided with a waste outlet 1b at the lower end of the side wall at the other end, and a movable grate 61 at the bottom of the casing 1c. A plurality of fixed greats 62 are alternately arranged in a state where they are alternately partially overlapped with each other. The movable grate 61 is fixed to a movable frame 63 extending from the dust inlet 1a to the discharge outlet 1b over the entire bottom surface of the casing 1c, and the fixed grate 62 is supported and fixed to the casing 1c at a location not shown. Support shaft 6
The movable frame 63 reciprocates in a direction indicated by an arrow in FIG.

Therefore, as shown in FIG. 5 (a), the refuse introduced from the refuse inlet 1a is piled up in a mountain shape having a vertex on the inlet 1a side. Then, the height of the piled-up garbage is averaged in the casing 1c, and the garbage is sequentially and uniformly discharged from the discharge port 1b. Therefore, there is also an effect that the quantitative supply of the refuse to the gasification furnace 2 by the quantitative supply device 32 in the next stage becomes easy.

In FIG. 5 (b), the portion where the dust is not sufficiently diffused is graded as a blind grade (having no holes) near the dust inlet so that the air flow can be shut off. The partition wall 6 is located below the movable frame 63.
8, two chambers 69, 70 are formed, and a fluid for drying dust is introduced from the chamber 69 on the side of the dust outlet 1b.
The drying fluid may be a movable great 61 or a fixed great 6
The dust is blown out toward the dust from a large number of holes provided in 2, so that the dust is dried. As the fluid for refuse drying, hot air may be newly introduced, but any device of the present gasification and melting system, for example, fluidized bed gasification furnace 2, melting furnace 4, secondary combustion furnace 5, or air Hot gas or preheated air obtained from the preheater 8 or the like may be introduced. By this pretreatment device 1, for example, refuse having a moisture content of about 50% by weight (combustible component 40% by weight, ash content 10% by weight) is dried to become refuse having a moisture content of about 30% by weight.

[0045] The waste-dried fluid discharged from the pretreatment device 1 can be any one of the devices in the present gasification and melting system.
For example, by introducing the fluidized bed gasification furnace 2, the melting furnace 4, the secondary combustion furnace 5, the pyrolysis gas combustion furnace 45, or the like, the amount discharged to the outside of the system of the present system is reduced, and the odor-dried fluid having a strong odor is dried. The burden of purifying the waste for air discharge is reduced, and at the same time, even if the waste drying fluid leaks to the fixed-quantity feeder 32 side, since it is within the system of the present system, trouble occurs in post-processing. Does not occur. Since the fluid after refuse drying has a high water content, after discharging from the pretreatment device 1, it is quickly cooled, cooled to a temperature lower than the dew point of the corrosive component contained in the fluid, and circulated and supplied to the respective devices. Things are desirable.

Further, when refuse having a non-uniform quantity and a large change in water content is put into the gasification furnace, refuse having a water content of about 50%, for example, is put into the gasification furnace 2 at once. In this case, the combustion of the refuse cannot be sustained without the auxiliary fuel, but in the present invention, the height of the refuse accumulated in a mountain shape is reduced by using a movable type 61 by using a great drying apparatus as the pretreatment apparatus 1. And averaged on the fixed grade 62, and are uniformly discharged from the discharge port 1b sequentially and dried at the same time, so that the quantitative supply of the refuse to the gasification furnace 2 by the quantitative feeder 32 becomes easy,
Since the refuse having a uniform moisture content is uniformly supplied, there is an advantage that it is not necessary to use an auxiliary fuel for refuse combustion in the fluidized bed in the gasification furnace.

Further, there is a pretreatment apparatus for drying refuse using a rotary kiln in the prior art. However, plastic in the refuse easily adheres to the inner surface of the kiln and the attached parts of the kiln. If a certain amount of drying air is introduced, some of the refuse adhering to the inside of the kiln will burn and partial gasification will occur, so the calorific value of the pyrolysis gas obtained in the gasification furnace may decrease. The above-mentioned great-type pretreatment device 1 of the present invention does not have such a problem.

In the gasification and melting system shown in FIG.
The combustible pyrolysis gas 15 generated in the fluidized bed gasifier 2 is completely burned by the combustion furnace 45 and possibly using the auxiliary fuel 17 before being introduced into the independent superheater 26. Combustion gas 23 used for heat recovery in the independent superheater 26
Is recycled as a fluidizing fluid in the fluidized-bed gasification furnace 2. Accordingly, the fluidized bed gasifier 2 is completely separated from the operation of the melting furnace 4 and the secondary combustion unit 5 which is the exhaust heat recovery device disposed downstream of the fluidized bed gasifier 2 in the gas flow path. It is possible to start or continue the operation.

For example, the components of the melting furnace 4 at a high temperature of about 1400 to 1500 ° C. often need to be replaced, or the operation of the melting furnace 4 for removing clinker deposited on the inner wall of the melting furnace 4 or the like. As described above, even when the melting furnace 4 and the secondary combustion unit 5 serving as the exhaust heat recovery device are shut down for reasons such as failure repair or repair work, the melting furnace 4 and the melting furnace 4 may be stopped. The operation of the fluidized-bed gasification furnace 2 and the independent superheater 26 can be completely separated from the operation of the secondary combustion unit 5 or the exhaust gas purification equipment 10 or the like.

At this time, the pyrolysis gas 15 from the fluidized-bed gasification furnace 2 is not only recirculated to the fluidized-bed gasification furnace 2 but also introduced into the vicinity of the superheater 6 of the secondary combustion furnace 5 whose operation is stopped. Or into the exhaust gas treatment facility 10. Further, the combustion gas 37 in the independent superheater 26 before the heat exchange is performed.
Is introduced into the upstream region of the superheater 6 of the secondary combustion furnace 5 by the blower 35, and is used for heating boiler water and steam circulating between the superheater 6, the steam drum 43, and the independent superheater 26, for example. Can be.

The char component separated by the cyclone separator 25 or the ash / char mixture 16 obtained from the bottom of the fluidized bed gasifier 2 is stored in the char service hopper 34, and the melting furnace 4 This can be used when starting operation. Similarly, if the fluidized-bed gasifier 2 and the independent superheater 26 are out of order,
When performing repairs, the melting furnace 4 and the secondary combustion furnace 5 can be operated independently.

When starting or restarting the refuse gasification / melting system, first, the fluidized bed gasification furnace 2 is started up. Since the pyrolysis gas 15 is not generated in the initial stage of the startup, the auxiliary fuel 17 of the independent superheater 26 is burned to generate the combustion gas 23, which is used as the fluidized fluid 13. When the pyrolysis gas 15 is generated,
By reducing the amount of the auxiliary fuel 17, the combustion gas 23
Is adjusted to an air-fuel ratio suitable for fluidized bed gasification. However, if the calorific value of the crushed refuse 11 is high, the calorific value of the pyrolysis gas 15 also increases, and the fuel itself burns only by the calorific value of the pyrolysis gas 15, so that the auxiliary fuel 17 may not be necessary.

As described above, when the entire refuse gasification and melting system is started, when the amount of the pyrolysis gas 15 is small or at a low temperature, the amount of combustion of the auxiliary fuel 17 in the independent superheater 26 is adjusted so that the fluidized fluid 13 is formed. Since the predetermined conditions can be easily set, the fluidized-bed gasification furnace 2 can be quickly started. This makes it possible to easily and quickly generate and operate the fluidized fluid 13 required for starting up the fluidized-bed gasifier 2, and therefore the fluidized-bed gasifier 2 and the entire gasification and melting system. Can be started or restarted quickly.

FIGS. 2 and 3 show another embodiment of the present invention.
Shown in FIG. 2 shows an example in which the cyclone separator 25 for separating the char in the pyrolysis gas 15 shown in FIG. 1 is not provided. The other configuration is the same as that shown in FIG. 1, and the description thereof is omitted. In the example shown in FIG. 3, an independent air preheater 29 is provided instead of the independent superheater 26, and a gas cooling tower 27 having an air preheater 8 is provided on the downstream side of the gas flow of the secondary combustion furnace 5. This is an example of arrangement. The installation position of the air preheater 8 may be on the downstream side of the gas flow of the gas cooling tower 27. A spray nozzle 42 for spray water 41 is provided downstream of the gas flow of the air preheater 8 in the gas cooling tower 27. The other configuration shown in FIG. 3 is the same as that shown in FIG. 1, and the description thereof is omitted. Further, a cyclone separator 25 for separating the char in the pyrolysis gas 15 shown in FIG. 2 may be installed at the top outlet of the gasification furnace 2 in the example shown in FIG.

In the example shown in FIG. 3, when the gasification and melting system is started or when the melting furnace 4 and the gas cooling tower side 27 downstream thereof are shut down, the independent air preheater 29 is supplied from the air blower 28. The air is supplied to the independent air preheater 29 directly from the bypass channel 47 that bypasses the air preheater 8.

As in the system shown in FIG. 3, even when the water-cooling type gas cooling tower 27 is installed without installing the secondary combustion furnace 5 shown in FIG. It is possible to independently operate the gas circulation system on the fluidized bed gasifier 2 side or the gas treatment system on the melting furnace 4 side independently, and to operate the respective systems independently during maintenance or failure or in the fluidized bed gasifier. (2) There is an effect that the starting or restarting of the gasification and melting system can be quickly performed.

FIG. 2 shows an example in which the cyclone separator 25 provided in the system shown in FIG. 1 is not provided. Similarly to this, the example shown in FIG.
In place of the independent superheater 26, air preheater, water heater, etc.
The cyclone separator 25 may or may not be provided even when equipment for heating the fluid is provided.

[0058]

According to the present invention, since the fluidized bed gasification furnace can be operated independently in a state of being separated from the melting furnace and the heat recovery unit, maintenance can be performed in the fluidized bed gasification furnace or the subsequent melting furnace. It is possible to continue the operation (warm-up operation) independently of each other even in the case of stopping due to the above or a failure or the like. In addition, the fluidized bed furnace can be quickly started up to a steady state, and the entire gasification and melting apparatus can be quickly started and restarted.

Further, hydrogen chloride in the pyrolysis gas in the fluidized-bed gasifier is used to concentrate the components without adversely affecting the operation of the fluidized-bed gasifier, including the fluidized-bed gasifier, by circulating the clean gas. This eliminates accumulation and has an effect on system maintenance and maintenance.In particular, clean pyrolysis gas with low hydrogen chloride, which causes high-temperature corrosion of the superheater, can be supplied to an independent heat exchanger such as an independent superheater. High-temperature and high-pressure steam can be collected in a superheater, and the amount of high-temperature superheated steam in the independent superheater can be easily stabilized by controlling the combustion of the pyrolysis gas in the furnace before the independent superheater. Therefore, high-efficiency power generation can be achieved.

The refuse before being put into the fluidized-bed gasifier is averaged by a pretreatment device which is a great dryer,
Since the waste can be discharged uniformly from the discharge port, it is easy to supply the refuse to the fluidized-bed gasification furnace at the same time, and at the same time, the garbage with a uniform moisture content is uniformly introduced into the fluidized-bed gasification furnace. In addition, there is no need to use an auxiliary fuel for burning waste in a fluidized bed in a fluidized bed gasifier. In addition, a fluid for refuse drying to be introduced into the pretreatment device and at least one of the devices of the gasification and melting device of the present invention, such as a fluidized-bed gasification furnace, a melting furnace, a heat recovery device, or an independent heat exchanger. Using the obtained preheated air or hot gas, the refuse-dried fluid discharged from the pretreatment device is guided to at least one of the gasification and melting devices to be discharged out of the gasification and melting device system. And the refuse drying fluid can be self-contained in the system.

[Brief description of the drawings]

FIG. 1 is a flow chart of a fluidized bed gasification and melting system according to an embodiment of the present invention.

FIG. 2 is a flow chart of a fluidized bed gasification and melting system according to an embodiment of the present invention.

FIG. 3 is a flow chart of a fluidized bed gasification and melting system according to an embodiment of the present invention.

FIG. 4 is a diagram showing an independent superheater according to an embodiment of the present invention.

FIG. 5 is a diagram of a pretreatment device according to an embodiment of the present invention.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 Pretreatment equipment 2 Fluidized bed gasifier 3 Separation equipment 4 Melting furnace 5 Secondary combustion furnace 6 Superheater 7 Evaporator 8 Air preheater 9 Economizer 10 Exhaust gas treatment device 25 Cyclone separator 26 Independent superheater 27 Gas cooling tower 29 Independent air preheater 33 Incombustibles / char extraction device 34 Char service hopper 45 Combustion furnace

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) The inventor, Manabu Yamamoto, 3-36, Takara-cho, Kure-shi, Hiroshima Pref. Babcock Hitachi Kure Research Laboratory (72) The inventor, Hiromichi Fujiwara 1-2-10, Isogo, Isogo-ku, Yokohama-shi, Kanagawa Inside the Babcock Hitachi, Ltd. Yokohama Engineering Center (72) Inventor Hideharu Mori 1-2-10 Isogo, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Inside the Babcock Hitachi, Ltd. Yokohama Engineering Center

Claims (18)

[Claims] 1. A fluidized bed gasification furnace system for pyrolyzing and gasifying combustibles containing solids using a fluidized medium, and a melting furnace for melting solids obtained by pyrolyzing and gasifying the combustibles. A fluidized bed gasification / melting device comprising a heat recovery device for recovering heat using a hot gas obtained in a bed gasification furnace and / or a melting furnace, and an exhaust gas purification device for purifying exhaust gas discharged from at least one of the above devices. In the fluidized bed gasifier system, a pyrolysis gas combustion furnace that burns pyrolysis gas generated in the fluidized bed gasifier, and an independent heat exchanger that performs heat exchange using the combustion gas of the combustion furnace, A fluidized-bed gasification / melting system comprising a gas circulation system including a recirculation gas flow path that uses combustion gas after heat exchange in the independent heat exchanger as a fluidization fluid of a fluidized-bed gasification furnace. apparatus. 2. A solid content and gas treatment system including a melting furnace and a heat recovery unit in addition to the gas circulation system including the fluidized bed gasifier, the independent heat exchanger, and the recirculation gas flow path,
2. The fluidized bed gasification and melting apparatus according to claim 1, wherein each of the two processing systems can be operated independently. 3. The fluidized-bed gasification and melting apparatus according to claim 1, further comprising an addition section for adding a desalting agent to the fluidized-bed gasification furnace system. 4. The fluidized-bed gasification and melting apparatus according to claim 1, wherein the independent heat exchanger is a steam superheater, an air preheater, or a feedwater heater. 5. A steam superheater is installed as an independent heat exchanger, steam temperature measuring means and steam flow rate measuring means are provided at a steam outlet of the steam superheater, and steam is measured based on measured values of the two measuring means. 2. A fluidized bed gasification and melting apparatus according to claim 1, further comprising a control device for controlling the combustion of the pyrolysis gas combustion furnace so that the superheated steam temperature and the superheated steam amount at the superheater outlet become predetermined values. . 6. A fluidized-bed gasification furnace system for pyrolyzing and gasifying combustibles containing solids using a fluid medium, and a melting furnace for melting solids obtained by pyrolyzing and gasifying the combustibles. A fluidized bed gasification / melting device comprising a heat recovery device for recovering heat using a hot gas obtained in a bed gasification furnace and / or a melting furnace, and an exhaust gas purification device for purifying exhaust gas discharged from at least one of the above devices. In the fluidized bed gasifier system, a pyrolysis gas combustion furnace that burns pyrolysis gas generated in the fluidized bed gasifier, and an independent heat exchanger that performs heat exchange using the combustion gas of the combustion furnace, A gas circulation system including a recirculation gas flow path that uses combustion gas after heat exchange in the independent heat exchanger as a fluidizing fluid of a fluidized bed gasifier, a fluidized bed gasifier and a pyrolysis gas combustion furnace; Generated by a fluidized-bed gasifier installed in the gas flow path between A separator for separating the char entrained in the gas and the pyrolysis gas, the fluidized bed gasification melting apparatus characterized by having a char storage tank for storing the separated char in the separator. 7. A char transfer path capable of supplying char from a char storage tank to a melting furnace is provided.
An apparatus for pyrolysis gasification and melting of combustibles as described in the above. 8. A solid-state furnace including a fluidized-bed gasifier, an independent heat exchanger, a gas circulation system including a recirculation gas flow path, a melting furnace using a char supplied from a char storage tank, and a heat recovery device. The fluidized-bed gasification and melting apparatus according to claim 7, wherein a separation and gas treatment system is provided, and each of the two treatment systems is operable independently. 9. A steam superheater is installed as an independent heat exchanger, steam temperature measuring means and steam flow rate measuring means are provided at a steam outlet of the steam superheater, and heat is measured based on measured values of the two measuring means. 7. The fluidized bed gasification and melting apparatus according to claim 6, further comprising a control device for controlling combustion of the cracked gas combustion furnace. 10. A fluidized-bed gasifier for pyrolyzing and gasifying combustibles containing solids using a fluidized medium, a melting furnace for melting solids obtained by pyrolyzing and gasifying the combustibles, and a fluidized bed. In a fluidized bed gasification / melting apparatus comprising a heat recovery apparatus for recovering heat using a hot gas obtained in a gasification furnace and / or a melting furnace and an exhaust gas purification apparatus for purifying exhaust gas discharged from at least one of the apparatuses. A fluidized-bed gasification and melting apparatus, comprising a pretreatment device for supplying a solid combustible to a fluidized-bed gasification furnace while leveling the thickness of the combustible by reciprocating motion of a plurality of movable plates. 11. Hot air generated from at least one of devices constituting a fluidized-bed gasification / melting device including a fluidized-bed gasifier, a melting furnace, a heat recovery device, and an exhaust gas purification device in a pretreatment device. 11. The fluidized-bed gasification and melting apparatus according to claim 10, wherein a gas flow path for supplying a gas other than hot air and hot air for drying the combustibles is provided. 12. An apparatus constituting a fluidized-bed gasification and melting apparatus including the fluidized-bed gasification furnace, a melting furnace, a heat recovery apparatus, and an exhaust gas purification apparatus by using the combustible material drying gas discharged from the pretreatment apparatus. The fluidized-bed gasification and melting apparatus according to claim 11, wherein the gas is supplied to at least one of the apparatuses. 13. A heat recovery medium using a pyrolysis gas obtained by pyrolyzing a combustible material containing a solid substance in a fluidized bed gasifier using a fluidizing medium as a heat source, recovering the combustible material by heat. In a fluidized bed gasification and melting method for melting a solid content obtained by cracking gasification, a pyrolysis gas generated in a fluidized bed gasification furnace is burned, and heat exchange is performed from a combustion heat of the combustion gas to a heat recovery medium. And then using the combustion gas after heat exchange as a fluidizing fluid of a fluidized medium in a fluidized bed gasifier. 14. A pyrolysis gas generated in a fluidized-bed gasification furnace is burned, heat is recovered from a combustion heat of the combustion gas to a heat recovery medium, and the combustion gas after the heat exchange is converted to a fluidized-bed gasification furnace. A gas circulation system used as a fluidizing fluid for the fluidized medium, and a solid content obtained by melting a solid content obtained by pyrolyzing and gasifying the combustible material and recovering heat from a hot gas generated during the melting to a heat recovery medium. And a gas processing system, wherein each processing system can be operated independently.
The fluidized bed gasification melting method as described in the above. 15. In the fluidized bed gasifier, char is generated in addition to the pyrolysis gas, and when the char is entrained by the pyrolysis gas, the char is separated from the pyrolysis gas and then separated. 2. A method according to claim 1, wherein the char is temporarily stored, and the stored char is used as a heat source when a solid content obtained by pyrolyzing and gasifying a combustible material is melted.
5. The fluidized bed gasification and melting method according to 4. 16. A desalting agent when pyrolyzing and gasifying the combustibles in a fluidized-bed gasifier or separating chars entrained by the pyrolysis gas generated in the fluidized-bed gasifier from the pyrolysis gas. The fluidized bed gasification and melting method according to claim 14, wherein a desalting reaction of the pyrolysis gas is carried out by adding a gas. 17. When the pyrolysis gas generated in the fluidized-bed gasifier is burned and heat is recovered to the heat recovery medium from the heat of combustion of the combustion gas, superheated steam is used as the heat recovery medium. 15. The fluidized-bed gasification and melting method according to claim 14, wherein the combustion control of the pyrolysis gas is performed such that the temperature and the amount of steam superheated by the heat of combustion of the gas become predetermined values. 18. A heat recovery medium using a pyrolysis gas obtained by pyrolyzing a combustible material containing a solid matter in a fluidized bed gasifier using a fluidized medium, and recovering the combustible material. In the fluidized-bed gasification and melting method for melting a solid content obtained by pyrolysis gasification, the combustible material is dried while the layer thickness of the combustible material is leveled, and the combustible material whose layer thickness and moisture content are substantially uniform Is supplied to a fluidized bed gasifier in sequence.