JPH10236801A - Method and device for recycling organic waste - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To solve various problems associated with incineration and dumping of organic waste and to provide a method of recycling organic waste to obtain inexpensive H ₂ and use it for NH ₃ synthesis. I do. SOLUTION: Two-stage gasification of organic waste a 24, 25
The gas obtained as a result is converted into H ₂ by a CO conversion 27 reaction, and is used as a raw material for NH ₃ synthesis 30 as a method for recycling organic waste. It is a combination of low-temperature gasification and high-temperature gasification. A fluidized-bed gasification furnace is used for low-temperature gasification, and a melting furnace is used for high-temperature gasification.
The melting furnace used for gasification at 0 to 650 ° C. and 600 to 850 ° C. in the freeboard part and used for the high temperature gasification is 1300
By burning at a high temperature at a temperature of not less than ° C, char and tar components can be gasified, and ash can be converted into molten slag and discharged from the furnace bottom.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the recycling of organic wastes, and more particularly to municipal solid waste, waste plastics and waste F.
RP, biomass waste, automobile waste, low-grade coal,
Gasification and combustion of waste oil and fuel substitutes etc. solidified or slurried of these, discharge metals and ash contained in the waste in a recyclable state, and obtain CO and CO obtained by the recovered gas. The present invention relates to a method and an apparatus for recycling organic waste, which uses H ₂ -containing gas as a raw material for NH ₃ (ammonia) synthesis. The above-mentioned fuel substitutes are called RDF (solidified fuel), which is obtained by crushing and sorting municipal solid waste, adding quicklime, etc., and compression-molding the municipal solid waste. Includes oily slurry fuels. FRP is a fiber reinforced plastic, and waste biomass includes water and sewage waste (contaminants, sewage, sewage sludge, etc.), agricultural waste (rice husk, rice straw, surplus products, etc.), forest waste (no Waste, bark, thinned wood, etc.), industrial waste (pulp chips, dust, etc.), and construction waste. Low-grade coal includes peat with a low degree of coalification, or waste produced during coal cleaning. In addition, the present invention is applicable to oil shale, kitchen garbage, corpses of beasts, waste clothing, paper waste, and any other organic matter.

[0002]

2. Description of the Related Art NH ₃ (ammonia) is a basic raw material in the chemical industry which is mass-produced as a raw material for nitric acid, various fertilizers (ammonium, ammonium sulfate, urea), acrylonitrile, caprolactam and the like. NH ₃ is synthesized from N ₂ and H ₂ under high pressure using a catalyst. H ₂ is formed by steam reforming such as natural gas and naphtha, or partial combustion of hydrocarbons such as petroleum, coal and petroleum coke. It has been obtained by gasification. On the other hand, municipal solid waste, waste plastic, waste FR
Organic waste typified by P, biomass waste, and automobile waste has been reduced in volume by incineration or has been landfilled untreated. Both directly and indirectly, the amount of these recycled is very small overall. H ₂ , a raw material of NH ₃ , is made from natural gas, naphtha, petroleum, coal, petroleum coke, etc. Most of these are imported from overseas. You have lost your competitive edge. For this reason, there has been a long-felt desire for raw materials that are inexpensive and can be procured locally.

[0003] On the other hand, incineration of solid waste also has the following problems and problems. Up to now, stoker furnaces and fluidized bed furnaces have been used for incineration treatment.
This has created disadvantages for energy recycling. That is, the air ratio during combustion is high, so the amount of exhaust gas is large, harmful dioxins are contained in the exhaust gas, the metals discharged from the furnace are not suitable for recycling because they are oxidized, and ash landfill This is the bottom of the land. The number of places to install volume reduction facilities such as ash melting facilities has recently been increasing, but this has resulted in an increase in the construction and operating costs of the entire waste disposal system. Furthermore, recently, there has been an increasing desire to make the most of the energy of solid waste. If solid waste is dumped on land without being treated, it becomes difficult to secure a dumping place and it is no longer acceptable for environmental protection. As a result, scrapped shredder dust and the like became extremely difficult to dispose of.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, and not only recovers resources in waste by establishing a utilization method, but also opens a route for separation and reuse. The degree of combustion is adjusted to an incomplete state to generate a synthesis gas having a preferable composition as a raw material of the NH ₃ synthesis raw material, to solve various problems associated with incineration and dumping of organic waste, and to obtain inexpensive H ₂ . Another object of the present invention is to provide a method and an apparatus for recycling organic waste used for NH ₃ synthesis and the like.

[0005]

In order to solve the above-mentioned problems, according to the present invention, an organic waste is gasified at a low temperature in a fluidized-bed gasification furnace, and the obtained gaseous substance and char are introduced into a melting furnace. Gas at high temperature, and CO and H ₂ O in the obtained gas
Is converted into H ₂ by a CO conversion reaction, and the H ₂ is recovered. In the above resource recycling method, the recovered H ₂ is
This is reacted with N _{2 in the} presence of a catalyst to provide NH ₃ as an ammonia synthesis raw material, and the incombustible substances can be converted into slag and recovered. The gasification at a low temperature and / or a high temperature in the above method can proceed under a pressure of 10 to 40 atm. As a gasifying agent, air is separated into N ₂ and N ₂ -free gas in a gas separation step. After that, the gas containing no N ₂ can be used as a gasifying agent for gasifying the organic waste. The fluidized-bed gasifier has an internal temperature of 45.
0-800 ° C. and the temperature of the fluidized bed is 450-650 ° C.
The gasification furnace comprises a fluidized bed portion and a free board portion, and the temperature of the fluidized bed portion is controlled to 450 to 650.
° C, and the temperature of the free board portion may be 600-800 ° C.

The fluidized-bed gasifier used in the present invention includes:
In particular, it is preferable to use an internal circulation type fluidized bed gasification furnace. The internal circulation type fluidized bed gasification furnace is for forming a circulating flow of a fluidized medium in a fluidized bed in the same reaction vessel, and the circulating flow is partially formed by a fluidized gas blown into the fluidized bed. This is caused by setting strong and weak parts.
Therefore, unlike a simple bubbling type fluidized bed, it has excellent waste dispersion and crushing functions, does not have the complexity and size of a simple circulating (external circulation) type fluidized bed, and has better dispersion and crushing functions than this. Therefore, it is easy to take a form and configuration that are easy to use as a pressurized mold. The internal circulation type fluidized bed gasification furnace is particularly preferably a cylindrical type.

The melting furnace has an internal temperature of 1300.
C. or more, and in the present invention, the fluidized-bed gasification furnace preferably has an internal temperature of 450 to 800 ° C., and the melting furnace has an internal temperature of 1300 ° C. or more. In the present invention, the gasifying agent fed into the fluidized-bed gasification furnace and the melting furnace for gasification has a total oxygen amount contained in total of the theoretical combustion oxygen amount necessary for completely burning waste. It is preferable that the amount of oxygen supplied to the fluidized-bed gasification furnace is 0.1 to 0.6 of the theoretical combustion oxygen amount.
It is better to be in the range of 1 to 0.3. The fluidized-bed gasification furnace can recover metals such as iron, copper, and aluminum in wastes from the furnace bottom in a non-oxidized and clean state, and the melting furnace converts ash into molten slag. Can be discharged from the furnace bottom.

[0008] Further, according to the present invention, the organic waste is produced at a low temperature.
Fluidized bed gasifier for gasification, and from the fluidized bed gasifier
A melting furnace for gasifying the gas at a high temperature; and
A quenching chamber for quenching gas and harmful gas and dust in the gas
Cleaning scrubber to be removed, CO and H in gas_TwoO to H_Two
And CO_TwoAnd CO in the gas_TwoAnd H
_TwoAn acid gas removing device for removing O and purified H_TwoWhen
N_TwoTo react with NH _ThreeHaving a reactor for synthesizing
An organic waste recycling system characterized by
You. In this resource recycling device, N_TwoAnd O_TwoSeparate
Air separator to separate the separated N_TwoTo the N
H_ThreeMeans for introducing into the synthesis reactor and separated O_TwoBefore
Means for introducing the fluidized bed gasifier and / or the melting furnace;
May be deployed.

[0009]

DETAILED DESCRIPTION OF THE INVENTION The organic waste used in the present invention is:
One or more of municipal solid waste, solidified fuel, slurry fuel, waste plastic, waste FRP, biomass waste, automobile waste, low-grade coal, and waste oil can be used.
A solid fuel such as coal and / or oil coke can be added to the organic waste as an auxiliary material depending on the properties to be used. The gasification is a combination of low temperature gasification and high temperature gasification. A fluidized bed gasification furnace is used for low temperature gasification, and a melting furnace is used for high temperature gasification. The fluidized-bed gasification furnace used for the low-temperature gasification has a fluidized-bed portion of 450 to 650.
C., and the free board section is maintained at 600 to 850 C., and the supplied waste is partially burned. From the furnace bottom, metals such as iron, copper and aluminum in the waste are recovered in an unoxidized and clean state. The melting furnace used for the high-temperature gasification,
Char and tar-containing gas supplied from the gasifier
At a high temperature of 300 ° C. or more, partial combustion occurs instantaneously, and ash is converted into molten slag and discharged from the furnace bottom.

At this time, if the melting furnace is a rotary melting furnace,
While high load combustion is possible, the char contained in the gas is blown to the furnace wall due to the centrifugal force accompanying the swirling flow,
It is burned over time in the slag phase formed on the wall. In this manner, since the char can be completely burned, a device or the like for reburning the char is not required. Implementing the gasification and slag simultaneously in parallel is an extremely effective resource recycling measure. Therefore, it is preferable to employ a rotary melting furnace as the melting furnace. Further, in the gasification, a mixed gas of O ₂ and steam obtained by air separation is used as a gasifying agent for producing H ₂ , while N ₂ obtained by air separation is used for NH ₃ synthesis. For the air separation, any of an adsorption method such as a cryogenic separation method PSA and a TSA method and a method using a separation (rich) membrane can be applied. Also, using oxygen-enriched air as a gasifying agent, H ₂
And a mixed gas having a composition ratio of N ₂ of 3: 1 can be used as it is for NH ₃ synthesis.

Further, according to the present invention, there is provided a fluidized bed gasifier for partially burning organic waste, a melting furnace for partially burning gas from the fluidized bed gasifier at a high temperature, and a gas from the melting furnace. And a quench chamber for cooling the organic waste. In the resource recycling apparatus, a scrubber for removing harmful gases such as HCl in the entrained gas and dust is provided downstream of the quenching chamber, and then CO for converting CO and H ₂ O in the gas into H ₂ and CO ₂ is provided.
It is preferable to provide a converter and an acid gas removing device for removing CO ₂ and H ₂ O after CO conversion, and a reactor for synthesizing NH ₃ by reacting purified H ₂ and N ₂ . Further, in the organic waste recycling apparatus,
Separately, an air separator for separating N ₂ and O ₂ is provided,
Means for introducing the separated N ₂ into the NH ₃ synthesis reactor and means for introducing the separated O ₂ into the fluidized-bed gasification furnace and / or the melting furnace may be provided.

At present, a "gasification combustion system" is under development as a new environmental protection type waste treatment technology that can replace incineration treatment. The present invention basically uses this system in terms of the device configuration. ing. The features when this gasification and melting system is used for incineration of waste are shown. Since the gas combustion replaces the conventional solid combustion, a low air ratio combustion of about 1.3 is realized, and as a result, the amount of exhaust gas is significantly reduced. The dioxins and their precursors in the exhaust gas are almost completely decomposed by the high-temperature combustion. Ash in the waste is collected as harmless slag.
Therefore, the life of the landfill can be prolonged, and it can be used for roadbed materials and the like. Since the functions of dioxin decomposition and ash melting are incorporated in the system, the entire apparatus is made compact, and the construction cost is lower than adding each function to a conventional incinerator. Significant reduction of exhaust gas volume also leads to cost reduction of exhaust gas treatment equipment.

[0013] Since the energy of gas, char, and tar generated in the gasifier can be effectively used for melting the ash, electric power and the like required when dedicated equipment for melting the ash is not required, and the operating cost can be kept low. It is easy to make a high efficiency power generation type flow. Metals such as iron, copper, and aluminum can be recovered in a recyclable, unoxidized and clean state. Although air is used as an O ₂ source in a normal incineration process, a fuel gas can be recovered by replacing it with pure O ₂ or oxygen-enriched air. The present invention is a process in which a gasification combustion system is integrated with an NH ₃ production facility, and solid waste such as municipal solid waste, waste plastic, waste FRP, biomass waste, automobile waste, and low-grade coal,
By collectively gasifying waste oil, various problems associated with incineration and dumping are solved, and the waste itself is effectively used.

In order to gasify the organic waste, it is preferable to use a gasification and melting system in which a fluidized bed gasification furnace and a melting furnace are combined. In a fluidized bed gasifier, sand (silica sand, olivine sand, etc.), alumina, iron powder, limestone, dolomite, etc. are used as a fluidizing medium. Among organic wastes, municipal waste, biomass waste, plastic waste, automobile waste, and the like are roughly crushed to about 30 cm. Solid fuel and slurry fuel are used as they are. 40 for low-grade coal
Crush coarsely to less than mm. These are divided and received in a plurality of pits, and after being sufficiently stirred and mixed in each pit, they are supplied to a gasification furnace as appropriate. Of course, the supply to the gasification furnace may be performed separately from each pit or may be performed by mixing. In addition, depending on the properties of the waste to be gasified (calorific value and moisture), coal, oil coke, or the like is added as an auxiliary material as needed. The amount to be added is appropriately set depending on the properties of the waste.

The organic waste is supplied to a gasification furnace, and is heated at 450 to 650 ° C. in a fluidized bed section and 600 ° C. in a free board section.
Perform low temperature gasification at ~ 800 ° C. Further, high-temperature gasification is performed at 1300 ° C. or higher in a subsequent melting furnace. In the gasification reaction, a mixed gas of O ₂ and H ₂ O or O ₂ alone is used as a gasifying agent after preheating as necessary. Therefore, the amount of heat required for gasification at each stage is obtained by partial combustion of the raw material. Gas, tar, and char are generated by gasification in the fluidized bed, but the lower the temperature, the higher the rate of tar and char generation and the lower the gas generation rate. On the other hand, among the metals contained in the waste, those having a melting point higher than the fluidized bed temperature are discharged from the bottom of the gasifier together with the fluidized medium. Therefore,
For example, aluminum can be recovered as a metal because the fluidized bed temperature is lower than 660 ° C., which is the melting point of aluminum.

In the free board section of the gasifier, 600 to 8
Although gasification is performed at 00 ° C., a considerable amount of undecomposed tar and char still remains. Freeboard gasification reduced the load on the melting furnace and increased the gasification rate, making it possible to reduce the size of the melting furnace. In addition, the capacity of the freeboard portion of the gasifier can be effectively used for gasification. However, freeboard gasification is not essential. In the latter melting furnace, tar and char are completely decomposed by high temperature gasification of 1300 ° C. or more, and the generated gas is H ₂ , C
It becomes a gas composed of O, CO ₂ , N ₂ and H ₂ O. Also,
The ash that has been turned into molten slag is continuously discharged from the furnace bottom of the melting furnace and then granulated, and is used as aggregate and other materials for civil engineering and construction materials.

[0017] The fluidized bed temperature of the gasifier is 450 ° C to 650.
The reason why the temperature is set to ° C is as follows. FIG. 6 shows the RDF
2 shows the thermal decomposition characteristics of the sample in a nitrogen atmosphere. In low-temperature gasification, it is desirable to gas the wastes and the like and gas components of tar as much as possible and to reduce solid components composed of combustibles and ash. For solid component chars, small-particle chars are transported to the melting furnace on the rising airflow in the gasifier, but large-particle chars that are not pulverized in the fluidized bed are discharged from the bottom together with incombustibles. . When the ratio of solid components is large, the amount discharged from the furnace must be increased in order to prevent accumulation in the fluidized bed. The discharged char is reused after removing sand and incombustibles, but the amount is preferably small. As shown in FIG. 6, the lower the pyrolysis temperature, the more solid components are generated. In addition, when the temperature is lower than 450 ° C., the thermal decomposition rate becomes extremely slow, and the operation becomes difficult because undecomposed substances are deposited on the fluidized bed. Conversely, as the temperature increases, the proportion of the solid component decreases, which is advantageous for gasification.
However, since the waste and the like are charged into the gasification furnace as nearly as possible without crushing, if the temperature becomes too high, the reaction speed increases. For this reason, the fluctuation of the amount accompanying the supply of the waste causes the fluctuation of the gas generation amount and the furnace internal pressure, and adversely affects the operation of the subsequent melting furnace. For example, a gasification and melting test using scrap car shredder dust showed that the gasification temperature was 6
It was found that when the temperature was set to 50 ° C. or lower, CO in the exhaust gas could be suppressed to 10 ppm or lower. In addition, many wastes contain metals, and it is an important theme to collect and recycle these metals without being oxidized. Among metals, recovery of aluminum is important, but since the melting point of aluminum is 660 ° C., the gasification temperature must be lower than this. Therefore, the upper limit temperature of gasification is preferably set to 650 ° C.

Usually, when producing a synthesis gas for a chemical industrial raw material, gasification is performed under a pressure of 10 to 40 atm.
Gasification is performed at normal pressure, and gas purification after CO conversion is 30 ~
It is considered as a practical method to perform the process under a pressure of 40 atm. As the gasifying agent used in the gasification furnace, H ₂ O is usually mixed with pure O ₂ obtained by cryogenically separating air, but CO ₂ recovered in the acid gas removing step may be mixed. . Similarly, N ₂ obtained by cryogenic separation of air is used directly as a raw material for NH ₃ synthesis. Alternatively, a method using O ₂ -enriched air as a gasifying agent is also conceivable. O ₂
If the composition ratio of H ₂ and N ₂ after CO conversion is adjusted to 3: 1 by adjusting the concentration, the raw material gas for NH ₃ synthesis can be used as it is. However, since the gas flow rate increases, the size of the gas processing equipment may increase. As described above, when waste is used as a raw material for synthesizing NH ₃ , there is a problem that the amount of waste is secured or the quality is stabilized. Another problem is how to deal with changes in waste quality during operation.

In order to solve such a problem in a practical manner, in the case where it is difficult to perform stable operation using only the waste or when starting up a plant, the present invention uses the waste as a high calorie such as coal or oil coke. in properties stable of, yet it may be used in combination solid fuel proven in H ₂ production. That is, it is possible to stabilize the quantity and quality of the gasification raw material by blending coal or oil coke so as to be about 20 to 40% of the whole. During the operation, if the quality of waste decreases for some reason and the concentration of H ₂ or CO in the product gas decreases, the properties of the product gas are stabilized by increasing the supply ratio of the solid fuel. I can do it. In addition, the coal used here is
It is not a low-rank coal belonging to waste, but rather a sub-bituminous coal and a bituminous coal class with a high degree of coalification.

Next, the present invention will be specifically described with reference to the drawings. FIG. 1 is a configuration diagram of a gasification and melting system used for incineration of ordinary waste. In the figure, 1 is a hopper, 2 is a fixed-quantity feeding device, 3 is a fluidized bed gasifier, 4 is a fluidized bed, 5 is a free board, 6 is a burner, 7 is a trommel,
8 is a bucket conveyor, 9 is a rotary melting furnace, 10 is a primary combustion chamber, 11 is a secondary combustion chamber, 12 is a slag separation section, 13
Is a burner. a is organic waste, b is air (for fluidized bed), b 'is air (for freeboard), b "is air (for melting furnace), c is coarse incombustible, d is silica sand, and e is generated gas ,
e ₁ is a combustion exhaust gas, and f is slag.

Organic waste a previously crushed as required
Is supplied to a fluidized-bed gasification furnace 3 using a screw-type quantitative supply device 2 after being supplied to a hopper 1. Air b is fed from below the fluidized bed gasifier 3 as a gasifying agent, and a fluidized bed 4 of silica sand is formed on the dispersion plate. The organic waste a is charged above the fluidized bed 4 and 450 to 70
In contact with O ₂ in air in a fluidized bed 4 maintained at 0 ° C.,
It is quickly gasified by pyrolysis. The fluidized medium is discharged from the bottom of the gasification furnace 3 together with the incombustibles, and the coarse incombustibles c are removed by the trommel 7. The separated silica sand d is transported upward by the bucket conveyor 8 and returned to the fluidized bed gasification furnace 3. Metals are contained in the coarse incombustibles c,
Practically, by setting the fluidized bed temperature to 500 to 600 ° C., iron, copper, and aluminum can be recovered in an unoxidized and clean state.

The organic waste a charged into the fluidized bed 4 is
It becomes gas, tar and carbide by pyrolysis gasification. The gas and tar vaporize and rise in the furnace. The carbide is finely pulverized by the disturbing motion of the fluidized bed 4 to form char. Because the char is porous and light, it is entrained in the upward flow of product gas. The use of hard silica sand as the fluid medium facilitates the grinding of carbides. Air b 'is blown into the free boat 5, and gasification is performed again at 600 to 850C. In this way, gas components are reduced in molecular weight and decomposition of tar and char proceeds. The product gas e discharged from the furnace top is supplied to the primary combustion chamber 10 of the swirling melting furnace 9 and gasified at a high speed of 1300 ° C. or higher while being mixed with the preheated air b ″ in the swirling flow. Gasification is completed in the secondary combustion chamber 11 and the gasified gas e
₁ is discharged from the slag separation section 12. The ash contained in the char as a result of the high temperature gasification becomes slag mist, is captured by the molten slag phase on the furnace wall of the primary combustion chamber 10 by the centrifugal force of the swirling flow, flows down the furnace wall, and enters the secondary combustion chamber 11. ,
It flows down from the bottom of the slag separation unit 12. Each of the primary combustion chamber 10 and the secondary combustion chamber 11 of the swirling type melting furnace 9 is provided with one burner 13 for raising the temperature. Thus,
Low air combustion of about 1.3 and melting of ash into slag are achieved.

FIG. 2 is another block diagram of the gasification and melting system used in the present invention, which is used for producing a synthesis gas of 10 to 40 atm. In the figure, the same reference numerals as those in FIG. 1 have the same names, 14 and 14 'are lock hoppers, 15 and 15' are screens, 16 is a fluid medium circulation line, 17 is a rotary melting furnace (integral type), and 18 is High temperature gasification room, 19 is quenching room,
20 is a cyclone, 21 is a gas scrubber, and 22 is a settler. Incidentally, a 'coal or oil coke for supplementary fuel, g and g' is the gasifying agent comprising a mixed gas of O ₂ and H ₂ O, g "is O _2. Pre crushed organic waste a is supplied quantitatively to the fluidized bed gasifier 3 through a lock hopper or the like (not shown), and from below the fluidized bed gasifier 3, a mixture of O ₂ and H ₂ O is used as a gasifying agent g. Then, the fluidized bed 4 of silica sand is formed on the dispersing plate 4. The organic waste a is introduced above the fluidized bed 4 and 450 to 650.
It contacts with the gasifying agent g in the fluidized bed 4 maintained at a temperature of 10 ° C. and a pressure of 10 to 40 atm, and is rapidly gasified by pyrolysis. The fluidized medium is discharged from the bottom of the fluidized-bed gasification furnace 3 together with the incombustibles, passes through the lock hopper 14, and the coarse incombustibles c are removed by the screen 15. The silica sand d under the sieve is transported upward by a fluidized medium circulation line 16 constituted by a bucket conveyor or the like, and returned to the fluidized bed gasification furnace 3. Although metals are contained in the coarse incombustibles c, iron, copper and aluminum can be recovered in an unoxidized and clean state by setting the fluidized bed temperature to 500 to 600 ° C. in practice.

By gasification in the fluidized bed 4, gas, tar,
Carbides are formed. The gas and tar vaporize and rise in the furnace. The carbide is finely pulverized by the disturbing motion of the fluidized bed 4 to form char. Because the char is porous and light, it is entrained in the upward flow of product gas. The use of hard silica sand as the fluid medium facilitates the grinding of carbides. The free boat 5 O ₂ and the H ₂ O gas agent g comprises a mixture of 'is blown, the gasification is carried out at 600 to 850 ° C.. In this way, gas components are reduced in molecular weight and decomposition of tar and char proceeds. The generated gas e ₂ discharged from the furnace top is supplied to the high temperature gasification chamber 18 of the swirling type melting furnace 17 and the preheated O ₂
Is burned and gasified at 1300 ° C. or higher by the gasifying agent g ″. The ash in the gas becomes slag mist due to high temperature and enters the quenching chamber 19 together with the gas. It is discharged to the outside via the lock hopper 14 ', and is separated by the screen 15' into coarse slag f 'and fine slag f''.

FIG. 3 is another structural diagram showing a fluidized bed gasifier and a melting furnace used in the present invention and peripheral parts of both furnaces.
It is also used for syngas production at about 40 atm. In this figure, an internal circulation type fluidized bed furnace is used for the fluidized bed gasification furnace 3 and a swirling type melting furnace is used for the melting furnace 17. FIG. 3 is different from FIG. 1 in that an internal circulation type fluidized bed furnace is used for the fluidized bed gasifier, and the discharge discharged from the bottom of the fluidized bed gasifier is first classified by the screen 15 and then classified. The coarse incombustible material c on the sieve and the fluid medium d under the sieve are separately placed in a lock hopper 14
The point is that the pressure is reduced through. In other words, by using an internal circulation type fluidized bed furnace as a gasification furnace, even if waste is injected from above the fluidized bed to the extent of coarse crushing, it is swallowed by the bed without accumulating on the fluidized bed, and the generated char Gasification of the char is promoted because it is uniformly dispersed in the fluidized bed,
The pulverization of the char is promoted by the swirling motion of the fluidized medium, the large-sized incombustibles c are smoothly discharged without staying in the fluidized bed, and the hotbed is hardly generated in the fluidized bed, so that agglomeration occurs. It is possible to enjoy the advantages of avoiding troubles such as clinker and clinker. As a result, taking out large incombustibles outside is a problem,
By separating the incombustibles and the fluid medium at first, large incombustibles are discharged through a specially designed lock hopper that prevents bridges, while the fine fluidic media is discharged through a commonly used lock hopper for high-temperature powder. Because of the discharge, the reliability of the device can be increased.

FIG. 4 is another block diagram showing the fluidized bed gasification furnace, the melting furnace, and the peripheral parts of both furnaces, and is used for producing synthesis gas at about 40 atm. Also in this drawing, an internal circulation type fluidized bed furnace is used as the fluidized bed gasifier 3 and a swirling type melting furnace is used as the melting furnace 9. 4 differs from FIG. 3 in that the discharge from the fluidized-bed gasification furnace 3 is reduced in pressure through a lock hopper 14 and then classified by a screen 15, and that the melting furnace 9 has high-temperature gasification chambers 10, 11 Is a rotary melting furnace having two chambers. That is, in this embodiment, since it is assumed that the organic waste does not contain the large-sized incombustible material c, the discharged material taken out from the furnace bottom is:
After the pressure is reduced through the commonly used high-temperature powder lock hopper 14, the noncombustibles c and the fluid medium d are separated by a classification operation using a screen. Also, as shown in FIG. 4, the high-temperature gasification chamber is not formed as a single vertical cylinder, but instead of a vertical cylinder 10 and a horizontal cylinder 11.
By combining the two high temperature gasification chambers, the residence time of the molten slag in the furnace is lengthened to reduce the amount of unburned carbon in the slag, Volatilization can be promoted.

FIG. 5 shows NH from organic waste of the present invention.
FIG. ₃ is an overall process diagram in the case of synthesizing No. ₃ ;
0, carbon monoxide conversion step 200, acid gas removal step 30
0, a nitrogen washing step 400, an ammonia synthesis step 500, and a sulfur recovery step 600. In the figure, 21 is a gas scrubber, 23 is an air separator, 24 is a low temperature gasifier for organic waste, 25 is a high temperature gasifier, 3
6 is a CO converter, 40 is an absorption tower, 41 is a condensate tank, 44 is a CO ₂ stripping tower, 50 is an H ₂ S stripping tower, 53 is an adsorption tower, 56 is an N ₂ washing tower, 57 is a cooler,
58 is an N ₂ gas compressor, 59 is an O ₂ gas compressor, 60 is a synthesis gas compressor, 62 is an NH ₃ synthesis tower, 68 is an NH ₃ refrigerator, 70 is an NH ₃ separator, and 72 is an NH ₃ storage tank. Is shown. Reference numerals 38, 48, 52, 57, 64, 66
Denotes a heat exchanger, and 30, 46, and 54 denote pumps.
In addition, i represents air, j represents O ₂ , q represents sulfur, and r represents ammonium sulfite.

The air i is separated from the O ₂ j by the 23 air separators.
And is divided into k of N _2, j of O ₂ is O ₂ gas compressor 59
After that, the organic waste a is provided as a gasifying agent for the low-temperature gasifier 24 and the high-temperature gasifier 25. Also, k of N ₂ after being compressed by the N ₂ gas compressor 58, which serve as an ammonia synthesis gas. Note that a cryogenic separation method is usually used for the air separation means. Gasification process 10
0, the organic waste a and the auxiliary raw material a ′ are subjected to low-temperature gasification at a low temperature, for example, 450 to 650 ° C. in the gasification furnace 24, and then, in the high temperature gasification furnace 25, the temperature is 1300 ° C. or more and the pressure is 1
Under operating conditions of 0 to 40 kg / cm ₂ G, it reacts with O ₂ , water vapor, etc. to be gasified, and generates a gas mainly composed of CO, H ₂ , H ₂ O, and CO ₂ . High temperature gasifier 2
The temperature in 5 is adjusted mainly by the amount of oxygen.
The high-temperature gasification furnace 25 is of a direct cooling type. In the high-temperature gasification furnace 25, a high-temperature gasification chamber 18 is provided at an upper part, and a quenching chamber 19 is provided at a lower part. After being cooled, it is discharged.

The rapid cooling generates a large amount of water vapor and accompanies the generated gas, and removes most of the slag generated in the high-temperature gasification chamber 18. Slag and water slurry are fed to the ash treatment process. The generated gas accompanied by a large amount of steam when leaving the cooling chamber 19 is washed by a venturi scrubber (not shown) and a gas scrubber 21 to remove accompanying ash, and then sent to a carbon monoxide conversion step 200. . On the other hand, the ash washing liquid at the bottom of the gas scrubber 21 is circulated and sent again to the quenching chamber 19 via the pump 30, and a part is sent to the ash processing step. In the carbon monoxide conversion step 200, the generated gas containing steam supplied from the gasification step 100 is treated as a raw material. The gas exiting the gas scrubber 21 is combined with the gas exiting the first-stage catalyst layer and the heat exchanger 38 to a temperature suitable for the CO conversion reaction.
After being heated by the CO, the CO in the gas sent to the CO converter 36 reacts with the accompanying steam on the CO conversion catalyst to generate H ₂ . The CO converter 36 is composed of a two-stage catalyst layer, and the catalyst filled in the CO converter 36 is a Co-Mo type catalyst. The first stage catalyst layer inlet temperature is about 300 ° C. The steam / dry gas ratio is about 1.5 (mol / mol) and the outlet temperature is 4 mol / mol.
Do not exceed 80 ° C.

The temperature at the inlet of the second-stage catalyst layer is about 300 ° C., the conversion is 90-95% or more, and the concentration of CO in the dry gas at the outlet of the CO converter 36 is 1-95.
It becomes 2% or less. Incidentally, the CO conversion reaction is as follows. _{CO + H 2 O = CO 2} + H 2 The reaction is exothermic, hot gases exiting the first stage catalyst layer, CO converter inlet gas and by heat exchange is cooled, into the second stage catalyst layer. The CO conversion reaction proceeds further in the second stage catalyst layer. The gas passing through the CO converter 36 is cooled down to about 40 ° C. in the heat exchanger 39 on the way.
Subsequently after being separated into condensed water and gas condensate tank 41, which will be described later N ₂ gas cooling part and the heat exchanger has been -17 ° C. in the purified gas leaving the wash column top 56 the next step the acid gases It is sent to the removal step 300. In the acid gas removal step 300, a lectizole method, which is a physical absorption process, is used to remove H ₂ S, COS, and CO ₂ which are impurities in the converted gas sent from the CO conversion step 200.

The gas cooled to -17 ° C. is introduced into the absorption tower 40. The absorption of CO ₂ gas in the absorption tower 40 is performed in countercurrent contact with methanol under a temperature operating condition of about −60 ° C., but the concentration of CO _{2 in} the gas leaving the absorption tower 40 is 10 to 20 ppm, and H ₂ S is about 0.1 ppm. The methanol used as the absorption liquid rises in temperature as it absorbs CO ₂ gas, and its absorption capacity decreases. Therefore, it is extracted from the middle of the absorption tower 40, cooled by the refrigerant ammonia and cold methanol, and returned to the absorption tower 40 again. It is. In this case, since methanol extracted from the middle of the absorption tower 40 contains H ₂ and CO in addition to CO ₂ and H ₂ S, a methanol (not shown) is used to recover H ₂ and CO. The dissolved H
Releases ₂ and CO. The released H ₂ and CO are pressurized by a compressor and used for circulation. On the other hand, in order to recover high-purity CO ₂ absorbed in methanol,
While being sent to the CO ₂ stripping tower 44 and decompressed, N ₂
The gas is stripped, most of the CO ₂ in methanol is released, and the released CO ₂ is recovered.

On the other hand, the methanol containing concentrated H ₂ S from the bottom of the CO ₂ stripper 44 is withdrawn via the pump 46, H ₂ S stripping tower 50 after being heated by the heat exchanger 48
Where it is indirectly regenerated by steam. H ₂ S
The H ₂ S-rich gas exiting from the top of the stripping tower 50 is supplied to the heat exchanger 52.
In cooled, sent to sulfur recovery step 600 is recovered as sulfur q or ₇ ammonium sulfate r. The methanol extracted from the bottom of the H ₂ S stripping tower 50 is supplied to the absorption tower 4 via a pump 54.
0 is circulated to the top. H ₂ rich gas containing CO ₂ and small amounts of CO coming from the absorption tower 40 trace amount, after methanol or CO ₂ is removed through the middle absorption tower 53, -190 ° C. nearby cooler 57 Cooled down to
It is sent to the N ₂ washing tower 56 which forms the nitrogen washing step 500.
In the nitrogen cleaning step 500, trace amounts of CO and CH ₄ are contained in the gas.
Are removed by washing with supercooled liquid nitrogen. on the other hand,
H ₂ gas is without being absorbed by liquid N ₂ since low boiling point, H ₂ rich purified gas containing N ₂ is obtained from the top of the N ₂ wash column 56.

The purified gas discharged from the top of the N ₂ washing tower 56 is mixed with a high-pressure liquid N ₂ gas cooled through a cooler 57 to have a composition suitable for ammonia synthesis, ie, H ₂ and H ₂ . After adjusting the ratio of N ₂ to about 3 (molar ratio),
Heated again through the cooler 57 and the ammonia synthesis step 5
Sent to 00. On the other hand, a part of the high-pressure N ₂ gas compressed by the N ₂ gas compressor 58 is cooled and liquefied by the cooler 57 and then sent to the N ₂ washing tower 56 to be directed to the gas entering from the bottom of the tower. Flow contact, during which CO, Ar, CH ₄
The impurities such as are moved absorbing removed fluid N ₂ side. The liquid N _{2 that} has absorbed CO, Ar, CH _4, etc. is N ₂
After exiting from the bottom of the washing tower 56 and being decompressed, it is sent out as boiler fuel.

The gas sent from the nitrogen cleaning step 500 is supplied to the first stage of the
After the pressure is increased to kg / cm 2 G, the pressure is then increased to 165 kg / cm 2 G in the second stage of the synthesis gas compressor 60 by being combined with the circulating gas from the ammonia separator 70 and sent to the ammonia synthesis tower 62. Ammonia synthesis tower 62
Is composed of a two-stage catalyst layer and is filled with an Fe-based synthesis catalyst. Pressure 164 at the inlet of ammonia synthesis tower 62
kg / cm2G, temperature 250 ° C. Ammonia synthesis is performed while the synthesis gas passes through the catalyst layer, and the ammonia synthesis reaction at this time is as follows. The temperature of the gas that has left the N ₂ + 3H ₂ = 2NH ₃ catalyst layer once exceeds about 500 ° C., but is cooled by a cold gas introduced from the middle of the ammonia synthesis tower 62.

The NH ₃ gas leaving the ammonia synthesis tower 62 has a pressure of 160 kg / cm 2 G and a temperature of 450 ° C.
After being cooled to around room temperature through the heat exchangers 64 and 66, it is further cooled through the ammonia refrigerator 68,
The majority of H ₃ is condensed. The condensed NH ₃ is separated into liquid NH ₃ and gas by the ammonia separator 70,
H ₃ is sent to the ammonia storage tank 72,
The gas separated as described above again enters the second stage of the syngas compressor 60 as a circulating gas, and is 165 kg / cm 2 G
, And circulated to the ammonia synthesis tower 62.

[0036]

According to the present invention, the following effects can be obtained. NH ₃ and H ₂ source such as synthetic, can be converted to procurable organic waste with inexpensive and their country. This gives N
It is substantially reduced the cost of production of H _3. The organic waste is gasified by the H _2,
Various problems associated with conventional incineration can be avoided. That is, exhaust gas disappears and no dioxins are generated.
In addition, since the ash in the waste becomes harmless slag, the life of the landfill can be prolonged, and it can be used as a roadbed material.

[0037] Metals such as iron, copper, and aluminum contained in waste can be recovered without undergoing recyclable oxidation. In this way, from the standpoint of effective use of waste and environmental protection, a gasification facility for organic waste is constructed adjacent to the ammonia synthesis facility, and the two are organically connected from the viewpoint of raw material utilization, thus providing a total You can enjoy the benefits of the system. By supplementing the waste with a solid fuel such as coal or oil coke, it is possible to deal with the problem of fluctuation in the quality and quantity of the waste. In particular, when the quality of generated gas is deteriorated due to a decrease in the quality of waste, a stable operation can be realized by increasing the mixing ratio of the solid fuel.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a gasification and melting system used in the present invention.

FIG. 2 is another configuration diagram of the gasification and melting system used in the present invention.

FIG. 3 is another configuration diagram of the gasification and melting system used in the present invention.

FIG. 4 is another configuration diagram of the gasification and melting system used in the present invention.

FIG. 5 is an overall process diagram in the case of synthesizing NH ₃ from the waste of the present invention.

FIG. 6 is a graph showing the thermal decomposition characteristics of RDF in an N ₂ atmosphere.

[Explanation of symbols]

1: hopper, 2: quantitative feeder, 3: fluidized bed gasifier, 4: fluidized bed, 5: free board, 6: burner, 7:
Trommel, 8: bucket conveyor, 9: revolving melting furnace, 10: primary combustion chamber, 11: secondary combustion chamber, 12: slag separation diagram, 13: burner, 14, 14 ': lock hopper, 15, 15': Screen, 16: Fluid medium circulation line, 17: Swirling melting furnace (integrated type), 18: High temperature gasification chamber, 19: Quenching chamber, 20: Cyclone, 21: Gas scrubber, 22: Settler, 23: Air separator , 24:
Primary gasifier, 25: Secondary gasifier, 34: Carbon scrubber, CO converter, 40: Absorption tower, 41: Condensate separator, 44: CO ₂ stripping tower, 50: H
₂ S stripping tower, 53: adsorption tower, 56: N ₂ wash column, 58:
N ₂ gas compressor, 59: O ₂ gas compressor, 60: synthesis gas compressor, 62: NH ₃ synthesis tower, 68: NH ₃ refrigerator,
70: NH ₃ separator, 72: NH ₃ storage tank, 10
0: gasification step, 200: carbon monoxide conversion step, 30
0: Acid gas removal step, 400: Nitrogen cleaning step, 50
0: ammonia synthesis step, 600: sulfur recovery step, a:
Organic waste, a ': coal or oil coke, b: air (for fluidized bed), b': air (for freeboard),
b ″: air (for melting furnace), c: coarse incombustible, d: silica sand,
e, e ₂ , e ₃ , e ₄ : generated gas, e ₁ : flue gas,
f: slag, f ′: coarse slag, f ″: fine slag,
g, g ′: gasifying agent (mixed gas of O ₂ and H ₂ O),
g ″: O ₂ , i: air, j: O ₂ , k: N ₂ , 1: NH
₃ , m: H ₂ O, n: fuel gas, O: acid gas + H
₂ O, q: sulfur, r: ammonium sulfite

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akisaku Fujinami 4-2-1 Motofujisawa, Fujisawa-shi, Kanagawa Inside Ebara Research Institute, Inc. (72) Inventor Kazuo Takano 11th Asahicho Haneda-cho, Ota-ku, Tokyo No. 1 Inside the Ebara Works Co., Ltd. (72) Inventor Masaaki Irie 11-1 Haneda Asahimachi, Ota-ku, Tokyo Inside the Ebara Works Co., Ltd. (72) Tetsuhisa Hirose 11-1 Haneda Asahi-cho, Ota-ku, Tokyo Stock (72) Inventor Shuichi Nagato 11-1 Haneda Asahi-cho, Ota-ku, Tokyo Ebara Corporation (72) Inventor Takahiro Ohshita 11-1 Haneda Asahi-cho, Ota-ku, Tokyo Ebara Corporation Inside the factory (72) Inventor Toshio Fukuda 2-3-1 Higashishinagawa, Shinagawa-ku, Tokyo UBE Building Ube Industries, Ltd.

Claims (14)

[Claims] 1. An organic waste is gasified at a low temperature in a fluidized-bed gasification furnace, the obtained gaseous substance and char are introduced into a melting furnace to gasify at a high temperature, and CO and H ₂ in the obtained gas are obtained. O
Is converted into H ₂ by a CO conversion reaction, and the H ₂ is recovered. 2. The method according to claim 1, wherein said low-temperature and / or high-temperature gasification comprises
2. The method for recycling organic waste according to claim 1, wherein the process proceeds under a pressure of about 40 atm. 3. The method for recycling organic waste according to claim 1, wherein the recovered H ₂ is used as a raw material for synthesizing NH ₃ , and incombustibles are converted into slag and recovered. Wherein said cold and / or hot gasification, as a gasifying agent, after separation of the air into the gas containing no N ₂ and N ₂ in gas separation processes, the use of a gas that does not contain the N ₂ The method according to claim 1, wherein the organic waste is recycled. 5. The fluidized bed gasifier has an internal temperature of 45.
The method for recycling organic waste according to claim 1, wherein the temperature is 0 to 800C. 6. The method according to claim 1, wherein the fluidized bed gasifier has a fluidized bed temperature of 450 to 650 ° C. 7. The fluidized bed gasifier comprises a fluidized bed section and a freeboard section, and the temperature of the fluidized bed section is 450 to 650.
2. The method for recycling organic waste according to claim 1, wherein the temperature of the free board is 600 to 800 ° C. 8. The method as claimed in claim 1, wherein the melting furnace has an internal temperature of 1300 ° C. or higher. 9. The fluidized-bed gasifier has an internal temperature of 45 ° C.
0-800 ° C, the melting furnace has an internal temperature of 1300 ° C
2. The method for recycling organic waste according to claim 1, wherein: NH ₃ synthesis of 10. The method of claim 3 wherein the resulting H _2, recycling method of organic waste, characterized in that is reacted with N ₂ in the presence of a catalyst to obtain the NH _3. 11. The organic fluidizer according to claim 1, wherein the fluidized-bed gasification furnace collects metals such as iron, copper, and aluminum in wastes from the furnace bottom in a non-oxidized and clean state. How to recycle waste. 12. The method according to claim 1, wherein the melting furnace converts the ash into molten slag and discharges it from the furnace bottom. 13. A fluidized-bed gasifier for gasifying organic waste at a low temperature, a melting furnace for gasifying gas from the fluidized-bed gasifier at a high temperature, and quenching the gas from the melting furnace. A quenching chamber, a cleaning scrubber for removing harmful gases and dust in the gas, a CO converter for converting CO and H ₂ O in the gas into H ₂ and CO ₂ , and a CO ₂ and H ₂ O in the gas. An organic waste resource recycling apparatus comprising: an acid gas removing device for removing; and a reactor for reacting purified H ₂ and N ₂ to synthesize NH ₃ . 14. The resource recycling apparatus according to claim 13, further comprising an air separator for separating N ₂ and O ₂ , and means for introducing the separated N ₂ into the NH ₃ synthesis reactor. Means for introducing separated O ₂ into the fluidized bed gasification furnace and / or the melting furnace.