JPH11181450A - Integrated gasification furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an integrated gasification furnace that can stably give produced gas having excellent properties in no need of a special pressure balance control between a gasification chamber and a char combustion chamber and a means for mechanical handling of high-temperature particles. SOLUTION: In one fluidized bed furnace, three functions of thermal cracking, gasification and char combustion are simultaneously performed and an elevated- temperature fluid medium in a char combustion chamber 2 is fed to a gasification chamber 1 as a heating medium for feeding the heat for thermal cracking and gasification. In this case, the gasification chamber 1 and a heat-recovering chamber 3 are perfectly partitioned from the furnace bottom to the ceiling with a partition wall 15 or they are arranged so that they may not contact with each other, and the gasification chamber 1 and the char combustion chamber 2 are perfectly separated with a partition wall 11 at the upper part higher than the interface of the fluidized bed, and the fluidization on the gasification chamber near the partition wall 11 is kept relatively weaker than that on the char combustion chamber 2 side. Thus, the fluid medium is allowed to move through an opening formed on the partition wall 11 near the furnace bottom from the char combustion chamber 2 to the gasification chamber 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an integrated gasifier having three functions of pyrolysis and gasification of fuel such as coal and municipal waste, char combustion, and in-bed heat recovery.

[0002]

2. Description of the Related Art At present, various attempts have been made in various countries around the world for a high-efficiency power generation system using coal. In order to improve the power generation efficiency, it is important to convert the chemical energy of coal into electric energy with high efficiency, but in recent years the direction of its development is being reviewed. Integrated Gasification Combined Cycle (IGCC) is a technology that gasifies coal, turns it into clean chemical energy, and then converts it directly to electricity with a fuel cell or high-efficiency power generation with a high-temperature gas turbine. However, since the technology is directed to complete gasification, the reaction temperature of the gasification section must be raised to a temperature range where ash can be melted, and there are many problems such as the problem of discharge of molten slag and durability of refractory materials. Have issues.
In addition, part of the heat energy is consumed by the latent heat of melting of the ash, and the generated gas discharged at a high temperature must be reduced to, for example, about 450 ° C. for gas purification, resulting in extremely low sensible heat loss. And it is necessary to supply oxygen or oxygen-enriched air in order to stably obtain a high temperature. For this reason, not only does the net energy conversion efficiency not increase, but the technology to generate electricity with high efficiency by using the product gas obtained in this way has not been completed, and at the present time the net power generation efficiency is never high. Has been found.

That is, in the integrated gasification combined cycle (IGCC),
The efficiency of the technology that ultimately converts to electrical energy has an upper limit, which is a bottleneck in improving efficiency as a whole. Therefore, the high-efficiency power generation technology that has attracted attention in recent years is
The purpose is to simply generate as much gas as possible at the upper limit of the gas temperature at the inlet of the gas turbine to increase the output ratio of the generated power from the gas turbine. Typical examples are a topping cycle power generation system and a power generation system using an improved pressurized fluidized bed furnace.

[0004] In an improved power generation system using a pressurized fluidized bed furnace, coal is first gasified by a pressurized gasifier and unburned carbon (so-called char) is burned by a pressurized char combustor. After cleaning the combustion gas from the combustor and the gas generated from the gasification furnace, respectively, they are mixed and burned in a topping combustor to obtain a high-temperature gas and drive the gas turbine. What is important in the power generation system using the pressurized fluidized-bed furnace is how to increase the flow rate of the gas flowing into the gas turbine. The most restrictive condition is cleaning of the generated gas.

The cleaning of the produced gas usually requires cooling to about 450 ° C. due to the optimum temperature of the desulfurization reaction in a reducing atmosphere. On the other hand, the higher the gas temperature at the inlet of the gas turbine, the higher the efficiency. Therefore, the temperature should be as high as possible. At present, the temperature is generally increased to less than 1200 ° C due to the heat resistance and corrosion resistance of gas turbine components. That is, the generated gas is required to have a calorific value enough to raise the temperature of the gas from a gas cleaning temperature of 450 ° C. to a gas turbine inlet temperature of 1200 ° C.

Therefore, in the power generation system using the improved pressurized fluidized bed furnace, the development of the system should be promoted in the direction of obtaining a product gas having a small amount as much as possible and having a high unit calorific value. Because, if the amount of generated gas to be cleaned at 450 ° C decreases, the sensible heat loss due to cooling decreases,
In addition, the minimum required calorific value required for the generated gas can be reduced. Furthermore, if the calorific value of the generated gas is equal to or greater than the calorific value required to raise the required gas temperature at the gas turbine inlet, the combustion air ratio can be increased to increase the amount of gas flowing into the gas turbine. This is because a further improvement in power generation efficiency can be expected.

In recent years, high-efficiency refuse combustion power generation technology has been developed in order to actively use municipal refuse as fuel. However, refuse sometimes contains a high concentration of chlorine. However, there is a problem that the steam temperature at the time of heat recovery cannot be increased to 400 ° C. or more due to the problem of corrosion of the heat transfer tube. Therefore, development of a technology that can overcome this problem is awaited.

As a typical example of a conventional gasifier using coal or the like as a fuel, there is a two-tower circulation type gasifier as shown in FIG. The two-tower circulation gasifier is composed of two furnaces (towers), a gasifier and a char combustion furnace, and circulates a fluid medium and char between the gasifier and the char combustion furnace to generate heat required for gasification. Is supplied to the gasification furnace with the sensible heat of the fluidized medium heated by the combustion heat of the char in the char combustion furnace. Since there is no need to burn the generated gas generated in the gasification furnace, there is a feature that the calorific value of the generated gas can be maintained high. However, in the two-tower circulation method, there are problems in handling high-temperature particles, such as ensuring a sufficient amount of particles circulated between the gasifier and char combustion furnace, controlling the amount of particles circulated, and stable operation, and controlling the temperature of the char combustion furnace by other operations. Due to operational issues that could not be achieved independently, the construction of large-scale actual equipment did not take place.

On the other hand, in recent years, as shown in FIG. 14, the entire amount of combustion gas from a char combustion furnace is led to a gasification furnace to compensate for the amount of heat for gasification, which tends to be insufficient only by sensible heat supply by circulating particles. Technology has been proposed. However, in order to direct the combustion gas discharged from the char combustion furnace to the gasification furnace, the system uses the above-mentioned "as little as possible,
It is also preferable to obtain a product gas having a high calorific value. " That is, when the amount of the char combustion gas exceeds the amount required for gasification or fluidization in the gasification furnace, the generated gas is diluted by unnecessary char combustion gas, so that not only the calorific value is reduced, but also the mixed gas is mixed. Even the excess char combustion gas is cooled to 450 ° C. for gas cleaning in a reducing atmosphere, and the amount of heat required to raise the gas temperature to an appropriate gas turbine inlet temperature increases. Conversely, when the char combustion gas amount is insufficient, fluidization of the gasification furnace becomes insufficient or the temperature of the gasification furnace decreases, so that it becomes necessary to supply air to the gasification furnace. Therefore, it is expected that limited coal types suitable for the system must be selected in order to realize this system. Any deviation from this limited coal type would require cooling even the excess char combustion gas to 450 ° C, or reducing the calorific value of the generated gas by introducing air into the gasifier. Therefore, it goes without saying that the efficiency of the entire system is reduced.

In this system, the temperature of the char combustion furnace is controlled by changing the height of the bed to change the heat transfer area in the bed. When the load is low, the combustion gas is exposed by the heat transfer tube exposed above the bed. The temperature of the gasification furnace, the fluidization speed, and the like change because of the cooling of the gas, which affects the gasification reaction speed and makes it difficult to operate the system stably.

[0011]

In view of such a situation, the present inventors have provided a gasification chamber,
We have devised an integrated gasification furnace in which three chambers, a char combustion chamber and a low-temperature combustion chamber, are provided via partition walls, respectively. In this, the char combustion chamber and the gasification chamber, and the char combustion chamber and the low temperature combustion chamber are provided adjacent to each other. This integrated gasifier is designed to overcome the problems of the two-column circulation system described above, and enables a large amount of fluid medium to circulate between the char combustion chamber and the gasification chamber. The heat of gasification can be sufficiently supplied only with heat, and the principle of a power generation system using an improved fluidized-bed furnace, which is the most easily realized, is to "obtain as little generated gas with high calorific value as possible". This is a potential technology.

However, in this technique, since the seal between the char combustion gas and the generated gas is not perfect, if the pressure balance between the gasification chamber and the char combustion chamber is not properly controlled, the combustion gas and the generated gas are mixed and the generated gas is mixed. There is a problem that the properties of the gas are reduced.

In the field of refuse combustion power generation systems,
Pyrolyzes garbage, volatilizes chlorine components with volatiles,
A proposal has been made to perform high-efficiency power generation by performing steam superheating with the combustion heat of the remaining char whose chlorine content has been significantly reduced. However, generally, almost no char is generated in the thermal decomposition of general refuse, so there is a high possibility that the char combustion heat required for steam superheating cannot be obtained. The fluid medium and the char as the heat medium flow from the gasification chamber side to the char combustion chamber side, but the same amount of the fluid medium is supplied from the char combustion chamber side to the gasification chamber side from the point of mass balance. However, in the above arrangement, there is a problem in that there is no other than mechanical conveyance using a conveyor or the like, difficulty in handling high-temperature particles, and large sensible heat loss.

The present invention has been made in view of the above circumstances, and does not require any special pressure balance control between the gasification chamber and the char combustion chamber, and does not require any mechanical means for handling high-temperature particles. Excellent product gas can be obtained stably, and even when flammable waste containing chlorine is used as fuel, there is little corrosion of steam superheaters (tubes) etc. It is an object to provide a mold gasifier.

[0015]

SUMMARY OF THE INVENTION According to the present invention, three functions of pyrolysis / gasification of fuel, char combustion, and in-bed heat recovery coexist in one fluidized bed furnace, and a high temperature inside a char combustion chamber is obtained. In an integrated gasification furnace in which a fluidized medium is supplied to a gasification chamber as a heat medium for supplying a heat source for thermal decomposition and gasification, the gasification chamber and the heat recovery chamber are completely separated from the furnace bottom to the ceiling by a partition wall, Alternatively, the gasification chamber and the char combustion chamber are disposed so as not to be in contact with each other, and the gasification chamber and the char combustion chamber are completely partitioned by a partition wall above the interface of the fluidized bed, and the fluidized state on the gasification chamber side near the partition wall is referred to as the char combustion chamber. By maintaining the fluidized state relatively weaker than the fluidized state on the side, it is possible to move the fluidized medium from the char combustion chamber side to the gasification chamber side through the opening provided near the furnace bottom of the partition wall. Features.

According to the above invention, since the gasification chamber and the char combustion chamber are completely separated by the partition wall above the interface of the fluidized bed, even if the gas pressure in each chamber fluctuates, the pressure balance is maintained. Does not occur and the combustion gas and the produced gas are mixed. Therefore, no special pressure balance control is required between the gasification chamber and the char combustion chamber.
By maintaining the fluidized state on the gasification chamber side near the partition wall relatively weaker than the fluidized state on the char combustion chamber side, an opening provided near the furnace bottom of the partition wall Through this, a large amount of fluidized medium can be stably moved from the char combustion chamber side to the gasification chamber side. For this reason,
No mechanical hot particle handling means is required to move the flowing medium from the char combustion chamber side to the gasification chamber side.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS.

FIG. 1 schematically shows a basic configuration of the present invention. The integrated gasification furnace of the present invention includes a gasification chamber 1, a char combustion chamber 2, and a heat recovery chamber 3 which respectively perform three functions of pyrolysis / gasification, char combustion, and heat recovery. It is housed in a furnace having a shape or a rectangle. The gasification chamber 1, the char combustion chamber 2, and the heat recovery chamber 3 are divided by partition walls 11, 12, 13, 14, and 15, and their bottoms are connected by a fluidized bed having a dense layer. . That is, the first partition wall 11 separates the gasification chamber and the char combustion chamber, the second partition wall 12 separates the char combustion chamber and the heat recovery chamber, and the second partition wall 12 separates the gasification chamber and the heat recovery chamber. It is partitioned by a third partition wall 13. Further, a settling char combustion chamber 4 is provided near the surface of the char combustion chamber in contact with the gasification chamber so that the flowing medium descends. Therefore, a fourth partition wall 14 is provided for partitioning the settling char combustion chamber 4 from other parts of the char combustion chamber. The settling char combustion chamber 4 and the gasification chamber 1 are separated by a fifth partition wall 15.

The first partition wall 11 between the gasification chamber 1 and the char combustion chamber 2 partitions almost entirely from the furnace ceiling 19 to the furnace bottom, but the lower end does not contact the furnace bottom. ,
There is an opening 21 near the furnace bottom. However, the upper end of this opening does not reach above the interface of the dense layer. The second partition wall 12 between the char combustion chamber 2 and the heat recovery chamber 3 has an upper end near the upper end of the dense layer and a lower end near the furnace bottom, and the lower end contacts the furnace bottom similarly to the first partition wall. However, there is an opening 22 near the bottom of the furnace that does not reach above the interface of the dense layer.

The third partition 13 between the gasification chamber 1 and the heat recovery chamber 3 completely partitions from the furnace bottom to the furnace ceiling. The upper end of the fourth partition wall 14 that partitions the inside of the char combustion chamber 2 to provide the settling char combustion chamber 4 is near the interface of the dense layer,
The lower end is in contact with the furnace bottom. A fifth partition wall 15 that separates the settling char combustion chamber 4 from the gasification chamber 1 is similar to the first partition wall 11, and partitions almost entirely from the furnace ceiling to the furnace bottom. There is an opening 25 near the furnace bottom, and the upper end of this opening is below the interface of the dense layer.

The fuel such as coal and refuse introduced into the gasification chamber receives heat from the fluid medium, and is pyrolyzed and gasified. The remaining dry char flows into the char combustion chamber 2 from the lower opening 21 of the first partition wall 11 together with the fluid medium. The fluid medium heated by the combustion heat of the char in the char combustion chamber 2 is the second fluid.
After flowing into the heat recovery chamber 3 over the partition wall 12, the heat is collected and cooled by the in-layer heat transfer tube 41, and then the second partition wall 12 is again formed.
Through the lower opening 22 into the char combustion chamber 2. On the other hand, the fluid medium heated in the char combustion chamber 2 is the fourth partition 1
4, flows into the settling char combustion chamber 4, and then flows into the gasification chamber 1 through the lower opening 25 of the fifth partition wall 15.

In the vicinity of the surface in contact with the settling char combustion chamber 4 inside the gasification chamber 1, a strong fluidized state is maintained as compared with the fluidization of the settling char combustion chamber 4. As a whole, the superficial velocity of the fluidizing gas may be changed depending on the location so as to promote the mixing and diffusion of the injected fuel and the fluidized medium. As an example, a swirling flow is formed as shown in FIG. To do.

The char combustion chamber 2 has a weak fluidized zone 2 in the center.
a, a strong fluidization zone 2b is provided in the peripheral portion, and the fluid medium and the char form an internal swirling flow. It is preferable that the fluidization speed in the strong fluidization zone in the gasification chamber and the char combustion chamber is 5 Umf or more, and the fluidization speed in the weak fluidization zone is 5 Umf or less. If there is a relative clear difference, there is no particular problem even if this range is exceeded. It is preferable to provide a strong fluidization zone 2b in a portion in contact with the heat recovery chamber 3 and the settling char combustion chamber 4 in the char combustion chamber 2. If necessary, the furnace bottom may be provided with a gradient from the weak fluidized region to the strong fluidized region.

The entire heat recovery chamber 3 is fluidized evenly, and is usually maintained at a maximum at a fluidized state weaker than the fluidized state of the char combustion chamber 2 in contact with the heat recovery chamber. Therefore, the superficial velocity of the fluidizing gas in the heat recovery chamber 3 is controlled between 0 and 3 Umf, and the fluidized medium forms a settling fluidized bed while flowing slowly.

The partition walls between the chambers are basically all vertical walls, but a projection may be provided if necessary. For example, as shown in FIG. 2, a central protruding portion 32 may be provided near the interface of the fluidized bed of the char combustion chamber 2 of the partition walls 12 and 14. Thereby, the flow direction of the flowing medium can be corrected near the partition wall, and the formation of the internal swirling flow can be promoted. Further, relatively large non-combustible substances contained in the fuel are discharged from a non-combustible substance discharge port 33 provided at the furnace bottom of the gasification chamber. In addition, the furnace bottom of each chamber may be horizontal, but as shown in FIG. 2, the furnace bottom is inclined according to the flow of the fluid medium near the furnace bottom in order to prevent a stagnant portion of the flow of the fluid medium. You may let it.

The most preferable fluidizing gas for the gasification chamber 1 is to recycle the product gas at a high pressure. In this way, the gas leaving the gasification chamber is purely gas generated from the fuel, and very high quality gas can be obtained. If this is not possible, a gas containing as little oxygen as possible, such as water vapor, should be used. When the bed temperature of the fluidized medium decreases due to an endothermic reaction during gasification, oxygen or a gas containing oxygen, for example, air may be supplied as necessary. The fluidizing gas supplied to the char combustion chamber 2 supplies a gas containing oxygen necessary for char combustion, for example, air, a mixed gas of oxygen and steam. The fluidizing gas supplied to the heat recovery chamber 3 uses air, steam, combustion exhaust gas and the like.

Since the freeboard portions of the gasification chamber 1 and the char combustion chamber 2 are completely separated from each other by a partition wall, as shown in FIG.
Even if the balance between P1 and P2 is slightly disturbed, the disturbance can be absorbed by only slightly changing the height difference between the two fluidized beds.
That is, since the gasification chamber 1 and the char combustion chamber 2 are completely partitioned by the partition wall 15 above the interface of the fluidized bed, even if the pressures P1 and P2 of the respective chambers fluctuate, this is not the case. The pressure difference can be absorbed by the layer height difference, and can be absorbed until one of the layers falls to the upper end of the opening 25. Accordingly, the upper limit of the pressure difference (P1-P2 or P2-P1) between the free space of the char combustion chamber 2 and the freeboard of the gasification chamber 1 that can be absorbed by the layer height difference is determined by the upper end of the lower opening 25 of the partition wall 15 that separates each other. Is almost equal to the head difference of the fluidized bed corresponding to the height from the fluidized bed interface.

FIG. 4 shows an embodiment in which the present invention is applied to a cylindrical furnace. A cylindrical partition wall 10 a concentric with the outer wall is provided in the furnace of the cylindrical integrated gasifier 10, and the inside of the partition wall 10 a forms the char combustion chamber 2. A settling char combustion chamber 4, a gasification chamber 1, and a heat recovery chamber 3 are respectively arranged in a fan shape in an annular portion surrounding the char combustion chamber outside the partition wall 10a.
The gasification chamber 1 and the heat recovery chamber 3 are arranged on opposite sides of the settling char combustion chamber 4 respectively.

FIG. 5 is a horizontal sectional view of the fluidized bed portion of the embodiment shown in FIG. A char combustion chamber 2 is provided at a central portion, a gasification chamber 1 is provided at a peripheral portion, and a heat recovery chamber 3 is provided on the opposite side, and a fan-shaped settling char combustion chamber 4 is provided between the gasification chamber 1 and the heat recovery chamber 3.
Are provided at two places. The aeration device provided at the furnace bottom of the fan-shaped gasification chamber 1 is also divided into a plurality of parts. A relatively slow fluidization zone 1a is provided, and the fluid medium in the gasification chamber also blows up in the strong fluidization zone,
It forms an internal swirling flow that settles in the weak fluidization zone. The fuel F introduced into the gasification chamber is diffused widely throughout the gasification chamber 1 by the swirling flow, and the gasification chamber can be effectively used.

As the fluidizing gas in the gasification chamber 1, a product gas is mainly recycled and used, or a gas containing no oxygen such as steam or combustion exhaust gas is used. However, if the temperature of the gasification chamber is too low, oxygen or a gas containing oxygen such as air may be mixed as necessary. An opening 21 is provided in the vicinity of the furnace bottom in a partition wall 11 between the gasification chamber 1 and the char combustion chamber 2, and a part other than the opening is completely partitioned over the ceiling. Gasification room 1
The fuel F that has undergone thermal decomposition and gasification flows out to the char combustion chamber 2 through the opening. The opening 21 may be provided over the entire surface of the gasification chamber 1 or may be provided only in the weakly fluidized region. In FIG. 5, the black arrow indicates the moving path of the flowing medium due to the sedimentation flow through the partition wall opening at the bottom of the furnace, and the gray arrow indicates the moving path of the flowing medium due to the upward flow over the upper end of the partition wall. Is shown.

The operating temperature of the gasification chamber 1 can be adjusted to an optimum temperature by the fuel. In the case of a fuel such as coal which has a relatively low gasification rate and generates much char, a high gasification rate can be obtained by keeping the temperature of the gasification chamber at 800 to 900 ° C. In addition, in the case of fuel that generates little char, such as municipal solid waste, keep the bed temperature at 350 to 450 ° C to maintain stable desalination and perform stable operation with a reduced volatile emission rate. Can be.

The air diffuser provided at the furnace bottom of the char combustion chamber 2 is divided into a central part and a peripheral part. The central part is a weak fluidized area 2a and the peripheral part is a strong fluidized area 2b. Is diffusing. The strong fluidized zone 2b forms an ascending fluidized bed in which the fluid medium blows up, and the weak fluidized zone 2a forms a settling fluidized bed in which the fluidized medium descends, and forms an internal swirling flow as a whole. In order to complete the char combustion and facilitate the supply of sensible heat to the gasification chamber 1, the char combustion chamber 2 is preferably maintained at a temperature as high as possible, and the bed temperature is preferably maintained at around 900 ° C. Generally, in the case of fluidized-bed combustion in which an exothermic reaction occurs inside, the risk of agglomeration increases in the operation around 900 ° C., but in the above embodiment, the heat diffusion and the char diffusion are promoted by the swirling flow in the char combustion chamber. Thus, stable char combustion without agglomeration can be achieved.

It is desirable that the settling char combustion chamber 4 be in a weakly fluidized state as a whole in order to form a settling fluidized bed.
As shown in FIG. 4, a weak fluidization zone 4a and a strong fluidization zone 4b are provided inside the settling char combustion chamber 4 to promote heat diffusion, and the side in contact with the gasification chamber becomes a settling fluidized bed. An internal swirling flow may be formed. In this embodiment, the partition wall 16 between the settling char combustion chamber and the heat recovery chamber has a lower end contacting the furnace bottom as shown in FIG. 4 and an upper end extending to a position considerably higher than the interface of the fluidized bed. , Settling char combustion chamber 4
The flow of the fluid medium between the heat recovery chamber 3 and the heat recovery chamber 3 is prevented.
This is because, for fuels containing a large amount of fixed carbon, such as coal, it is desirable that the flow medium flowing into the gasification chamber from the sedimentation char combustion chamber be as hot as possible, and that the flow medium cooled in the heat recovery chamber 3 be mixed. , And gasification chamber 1
This is because it is not preferable that the high-temperature fluid medium to flow into the heat recovery chamber 3 flows into the heat recovery chamber 3.

However, when the present invention is used for gasification combustion of refuse, the upper end of the partition wall 16 should be close to the fluidized bed interface,
An opening may be provided near the furnace bottom to cause circulation of the fluid medium between the settling char combustion chamber 4 and the heat recovery chamber 3. This is because, in the case of a fuel having a low char generation rate such as refuse, the combustion temperature in the char combustion chamber becomes insufficient unless the gasification rate is lowered by lowering the temperature of the gasification chamber. In such a case, as shown in FIG. 6, the air diffuser at the furnace bottom of the heat recovery chamber 3 is divided, and the heat recovery chamber 3 is partitioned by the partition wall 16a. The other is for the settling char combustion chamber, which makes it possible to control the temperatures of the char combustion chamber and the gasification chamber independently. At this time, the air diffuser at the hearth of the settling char combustion chamber 4 is preferably divided so that the portion in contact with the heat recovery chamber forms the strong fluidization region 4b.

In the heat recovery chamber 3, an in-layer heat transfer tube 41 is arranged radially, and the fluid medium flowing from the char combustion chamber 2 across the partition wall 12 is cooled there, and the lower opening of the partition wall 12 is opened. 22 returns to the char combustion chamber 2 again, but since the in-layer pipe pitch is widening toward the peripheral portion,
The resistance when the flowing medium flows through the inner tube group is smaller in the peripheral portion. For this reason, the fluid medium flowing from the char combustion chamber 2 is uniformly dispersed also in the peripheral portion, and the entire volume of the heat recovery chamber 3 can be effectively used, so that the overall structure is compact.

FIG. 7 shows an embodiment of a rectangular furnace according to the present invention. When the present invention is carried out at normal pressure, it is not particularly necessary to make the outer wall of the gasification furnace pressure-resistant, so such a rectangular furnace is also suitable from the viewpoint of production. In the case where it is preferable to lower the temperature of the gasification furnace depending on the type of fuel and operate it, the heat recovery chamber 3 is used for the char combustion chamber and the sedimentation char combustion chamber as shown in FIG. Each partition wall 1
It is preferable that the temperature of the fluidized medium supplied to the gasification chamber 1 is controlled by controlling the temperature of the charcoal combustion chamber 2 independently of the temperature of the charcoal combustion chamber 2.

When applied to a rectangular furnace as shown in FIG. 7, the fluid medium in the portion where the weak fluidization zone of the char combustion chamber 2 and the heat recovery chamber 3 are in contact is both in a weak fluidized state. In some cases, a clear moving direction is not determined, and the function does not function effectively as a heat medium. In such a case, as shown in FIG. 8, the portion may be opened to the outside of the furnace and used effectively, for example, by providing a supply port for a recycler.

FIG. 9 shows an embodiment in which the present invention is applied to a combined cycle power generation system. The integrated gasifier 10 of the present invention is disposed in a pressure vessel 50 and operates under pressure. The outer wall of the gasification furnace 10 may have an integral structure also serving as a pressure vessel. A part of the combustible gas generated in the gasification chamber 1 is supplied to a normal-pressure melting furnace 54 and is used as heat of melting ash. The remaining combustible gas is removed together with the char combustion gas and then guided to the topping combustor 53 to generate a high-temperature gas to be supplied to the gas turbine 55.

A heat transfer tube 42 may be provided in the upper part of the char combustion chamber as needed. Even if the fuel contains chlorine, the char combustion gas in the present embodiment hardly contains chlorine.
It can be used for steam superheating of ℃ or more. Since the in-layer heat transfer tube 41 disposed in the heat recovery chamber 3 is not more corrosive than the heat transfer tube 42, the heat transfer tube 42 is used as a steam superheater.
It can handle even higher temperatures. If the chlorine concentration in the fuel is relatively high, the chlorine concentration on the combustible gas side will also be high,
The entire amount of the combustible gas is led to the high-temperature melting furnace 54 to prevent corrosion of the topping combustor 53 and the gas turbine 55.

FIG. 10 shows another embodiment in which the integrated gasifier of the present invention is used in a combined cycle power generation system. In the case of a fuel having a relatively high calorific value, such as coal, the temperature of the high-temperature melting furnace can be raised to a temperature sufficient for melting without bringing the high-temperature melting furnace into a complete combustion state. It is effective to arrange the high temperature gasifier 60 to generate gas. As a high-temperature gasification furnace, a gasification furnace of the type in which both gas and slag flow down, the slag is heated by the heat of the gas, and the gas is once immersed in water and quenched while preventing poor flow due to slag cooling. It is suitable. This is because the product gas thus obtained contains almost no chlorine and can be used not only as a chemical raw material but also as a gas turbine fuel.

FIG. 11 shows an embodiment in which the present invention is applied to a fluidized bed furnace at normal pressure. In this embodiment, even if chlorine is contained in the fuel, the heat transfer tube 41 in the layer disposed in the heat recovery chamber 3 and the heat transfer tube 42 in the free board portion of the char combustion chamber are almost in contact with chlorine as described above. Therefore, the steam temperature can be raised to not less than 350 ° C, which is the maximum steam temperature of the conventional refuse incinerator, and to 500 ° C or more. Further, in a place where the combustion gas is blown from the char combustion chamber 2 to the gasification chamber 1 side, the residual oxygen in the combustion gas reacts with the combustible gas and becomes high temperature, so that the combustion of the char and the decarboxylation of limestone are promoted, Combustion efficiency and desulfurization efficiency can be improved. At this time, the pressure loss when blowing from the char combustion chamber 2 into the gasification chamber 1 is about 200 to 400 mmAq.
The head of the fluidized bed from the bottom of
Since it is not less than 00 to 2000 mmAq, the pressure difference can be maintained naturally only by the height of the gasification chamber being slightly lower than the height of the char combustion chamber as shown in FIG. No control is required.

FIG. 12 is a process flow for melting ash using gas generated from the integrated gasifier of the present invention. In this embodiment, a gasification chamber 1, a char combustion chamber 2, a heat recovery chamber 3, a settling char combustion chamber 4 and the like are provided in a furnace body 10 at normal temperature, and a large amount of a fluid medium is circulated through these chambers. In order to make stable driving possible,
This is the same as each of the above embodiments. Also in this embodiment, as in FIG. 9, a part of the pyrolysis gas in the gasification chamber 1 is introduced into the high-temperature melting furnace 54 and used for the ash melting heat treatment.
The remaining pyrolysis gas, together with the char combustion gas, is removed from the deduster 52.
After being dusted off, it is led to the topping combustor 53,
The high-temperature gas generated by the high-temperature combustion is supplied to a gas turbine 55 directly connected to a generator 57.

[0043]

By configuring the integrated gasifier as in the present invention, the following effects are produced. First of all, in the gasification chamber, the fuel is pyrolyzed and gasified by the sensible heat of the high-temperature fluidized medium flowing from the char combustion chamber through the settling char combustion chamber, so the gas exiting the gasification chamber is pure. It is a gas generated from the fuel or a mixed gas of the gas generated from the fuel and the fluidizing gas necessary for fluidizing the gasification chamber at a minimum, and has a high calorific value. Moreover, since the char combustion gas and the produced gas do not mix, a gas having a high calorific value can be obtained.

If a small amount of gas having a high calorific value is obtained, the heat loss due to cooling for cleaning the generated gas is small, and a high-temperature gas mixed with the char combustion gas and led to the gas turbine can be easily obtained. Power generation efficiency can be improved. In addition, various fuels having greatly different volatile components can be controlled without any modification of the equipment because the temperature of the char combustion chamber and the gasification chamber can be controlled freely.

Even when fuel such as municipal solid waste containing chlorine is used, most of the chlorine in the fuel is released to the gas side in the gasification chamber and hardly remains in the char flowing into the char combustion chamber. . For this reason, the chlorine concentration in the gas in the char combustion chamber and heat recovery chamber is maintained at a remarkably low level, and even if high-temperature steam recovery is performed using the in-layer pipe located in the heat recovery chamber as a superheater pipe, high-temperature corrosion will not occur. There is almost no danger and highly efficient energy recovery is possible.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a basic concept of an integrated gasification furnace of the present invention.

FIG. 2 is a view showing a modification of FIG. 1 in a case where a furnace bottom is inclined and a projection is provided on a partition wall.

FIG. 3 is an explanatory diagram of a pressure control function of the integrated gasification furnace of the present invention.

FIG. 4 is a structural view of an embodiment in which the integrated gasification furnace of the present invention is embodied by a cylindrical furnace.

FIG. 5 is a horizontal sectional view of the fluidized bed portion of FIG.

FIG. 6 is a diagram showing a modification of FIG. 5;

FIG. 7 is a horizontal sectional view of an embodiment in which the integrated gasification furnace of the present invention is embodied by a rectangular furnace.

FIG. 8 is a diagram showing a modification of FIG. 7;

FIG. 9 is an explanatory diagram of an embodiment of a combined cycle power generation system using the integrated gasifier according to the present invention.

FIG. 10 is a diagram showing a modification of FIG. 9;

FIG. 11 is an explanatory view of one embodiment of the normal-pressure integrated gasifier of the present invention.

FIG. 12 is an explanatory diagram of an embodiment of a combined cycle power generation system using the integrated gasifier of FIG. 11;

FIG. 13 is an explanatory view of a conventional two-tower circulation type gasification furnace.

FIG. 14 is an explanatory diagram of a combined power generation system using a conventional fluidized bed furnace.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Gasification chamber 2 Char combustion chamber 3 Heat recovery chamber 4 Sedimentation char combustion chamber 10 Integrated gasifier 11, 12, 13, 14, 15 Partition wall 21, 22, 25 Opening

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI F02C 3/28 F23C 11/02 311 F23C 11/02 311 F23G 5/30 ZABS F23G 5/30 ZAB ZABH B09B 3/00 302F (72 Inventor Nobutaka Kashima 11-1 Haneda Asahicho, Ota-ku, Tokyo Ebara Corporation (72) Inventor Katsutoshi Naruse 11-1 Haneda Asahi-cho, Ota-ku, Tokyo Ebara Corporation (72) Inventor Katsuyuki Aoki 11-1 Haneda Asahi-cho, Ota-ku, Tokyo Inside Ebara Corporation (72) Inventor Shinji Sekikawa 11-1 Haneda Asahi-cho, Ota-ku, Tokyo Inside Ebara Corporation (72) Inventor Shuichi Nagato Tokyo 11-1 Haneda Asahi-cho, Ota-ku, Tokyo Ebara Corporation

Claims (8)

[Claims] 1. A fluidized-bed furnace having three functions of pyrolysis and gasification of fuel, char combustion, and in-bed heat recovery in one fluidized-bed furnace to pyrolyze and gasify a high-temperature fluidized medium in a char combustion chamber. In the integrated gasifier for supplying a heat medium to the gasification chamber as a heat medium, the gasification chamber and the heat recovery chamber are completely separated from the furnace bottom to the ceiling by a partition wall, or are arranged so as not to be in contact with each other. In addition, the gasification chamber and the char combustion chamber are completely partitioned by a partition wall above the interface of the fluidized bed, and the fluidization state on the gasification chamber side near the partition wall is more relative to the fluidization state on the char combustion chamber side. An integrated gasification furnace characterized by moving a fluidized medium from a char combustion chamber side to a gasification chamber side through an opening provided in the vicinity of the furnace bottom of the partition wall by maintaining the fluidized state in a partially fluidized state. . 2. A weakly fluidized region provided at a location in contact with the gasification chamber in the char combustion chamber is a settling char combustion chamber, and is separated from other char combustion chambers by a partition wall extending from the furnace bottom to near the fluidized bed interface. The integrated gasifier according to claim 1, wherein the gasifier is divided. 3. A strong fluidizing zone and a weak fluidizing zone are provided in the char combustion chamber, the settling char combustion chamber, and the gasification chamber, respectively, to generate an internal swirling flow of a fluid medium in each chamber. The integrated gasifier according to claim 1 or 2, wherein 4. The heat recovery chamber is disposed so as to be in contact with the strong fluidization region of the char combustion chamber, and the heat recovery chamber and the char combustion chamber have an opening near a furnace bottom, and the upper end thereof has a fluidized bed interface. The partition wall reaching the vicinity of the partition wall, and the fluidized state on the side of the char combustion chamber near the partition wall is made relatively stronger than the fluidized state on the side of the heat recovery chamber to generate the circulating force of the fluid medium. The integrated gasifier according to any one of claims 1 to 3, characterized in that: 5. The heat recovery chamber is disposed so as to be in contact with a strong fluidization region of a settling char combustion chamber, wherein the heat recovery chamber and the settling char combustion chamber have an opening near a furnace bottom, and the upper end thereof is fluidized. The partition wall reaching the vicinity of the floor interface is partitioned, and the fluidized state on the settling char combustion chamber side near the partition wall is made relatively stronger than the fluidized state on the heat recovery chamber side to generate circulation force of the fluid medium. The integrated gasifier according to any one of claims 1 to 4, wherein: 6. The integrated gasification furnace according to claim 1, wherein a gas containing no oxygen, such as steam, is used as the fluidizing gas in the gasification chamber. 7. The furnace bottom of each of the gasification chamber, char combustion chamber and heat recovery chamber is inclined along a streamline of a fluid medium near the furnace bottom. An integrated gasifier according to any one of the above. 8. The temperature of the gasification chamber according to claim 1, wherein the temperature of the gasification chamber is controlled by controlling the fluidization state of a weak fluidization zone in contact with the gasification furnace in the char combustion chamber. An integrated gasifier according to any one of the above.