JPH086098B2 - Fine powder raw material gasifier and its operating method - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to a carbon fine powder raw material gasifier such as coal, coke and coal liquefaction residue, and more particularly to a gasifier for efficiently gasifying carbon fine powder raw materials having different properties and an operating method thereof.

[Prior art]

Conventionally, various systems using a fixed bed, a fluidized bed, a spouted bed, etc. have been proposed for a gasifier. Among these methods, the method using a spouted bed is a method in which a raw material such as coal is made into a fine powder and is mixed with an oxidizing agent such as oxygen or air to have a melting point of 1300 to 16
It is supplied to the gasifier at a temperature of 00 ℃) to gasify the carbon fine powder raw material, so the gasification efficiency is high, the applicable raw material species are wide, and there are few pollution by-products, compared to other methods. It is suitable for production of synthesis gas, combined power generation, and fuel production such as fuel cells. As a spouted bed type carbon fine powder raw material gasifier, carbon fine powder raw material such as pulverized coal or char (carbon particles that scatter with gas because the volatile content of the raw material disappears) and gasification agent (oxygen, air, steam, etc.) There are a one-stage type device that blows from the same burner and a two-stage type device that installs a burner that blows only pulverized coal or char alone in addition to the above-mentioned burner. The gasification reaction is roughly classified into the following methods. Raw material → Char, H ₂ , CO, CO ₂ ,, CH ₄ …… (1) Char ＋ O ₂ → CO ₂ , CO, H ₂ …… (2) Raw material ＋ O ₂ → CO, CO ₂ , H ₂ …… (3 ) Equation (1) is a thermal decomposition reaction, and is likely to occur in the above-described two-stage system due to a burner that blows only raw materials such as pulverized coal alone. As a well-known representative example of the system in which the reactions of the formulas (1) and (2) are clearly distinguished and coexisted, there is the US BI-GAS process. Further, there is a process based on the reaction formula (3) in which the carbon fine powder raw material and the gasifying agent are simultaneously supplied from the burner and the formulas (1) and (2) are not intentionally distinguished, and a typical example is the Texaco process. , Shell-Kop
There is a pers process etc. Further, the inventors of the present invention, for example, as shown in Japanese Patent Application No. 58-47162 and Japanese Patent Application No. 58-50496, provided two stages of burners with different distributions of the oxidant in the gasifier, and provided two stages. We are proposing a two-stage process with multiple burners installed. FIG. 5 shows a schematic configuration diagram of the gasifier. The gasifier is generally a pressurizing device in order to make the device compact, and the carbon fine powder raw material is quantitatively supplied to the feeder 40 via the atmospheric hopper 10 and the two pressurizing hoppers 20 and 30, and A carrier gas such as nitrogen gas introduced through a carrier line 51 by an ejector 50 downstream of 40 is supplied to an upper burner 61 and a lower burner 62. Oxidants such as oxygen and air are sent to the upper burner 61 and the lower burner 62 from lines 63 and 64, respectively. Then, the carbon fine powder raw material is gasified in the gasification chamber 65 of the gasifier 60, and the produced gas is discharged from the line 69. By distributing the oxidant supply amount to the lower burner 62 more than that to the upper burner 61,
The temperature in the lower part of 65 is raised to the temperature at which the slag melts. By distributing the oxidant as described above, especially in the lower burner 62, raw material + O ₂ → CO ₂ + H ₂ O …… (4) Especially in the upper burner 61, char + CO ₂ → 2CO …… (5) Char + H ₂ O → H ₂ + CO …… (6) makes the reaction easier. In this method, a large amount of the oxidant is distributed to the lower burner 62, the lower part in the gasification chamber 65 is heated to a high temperature, and the upper burner 61 attempts to generate active char. Since the gasification reaction represented by the formulas (5) and (6) has a reaction rate as small as about 1/20 to 1/50 as compared with the dry distillation reaction of the formula (1), the formulas (5) and (6) are represented. It is important how quickly the reaction of can be performed.

[Problems to be Solved by the Invention]

In countries that rely on imports for most of their coal, such as Japan, it is rare for a gasifier to use only one type of feedstock, and it is common to use several types of feedstock. As for raw materials, there is an increasing need for gasifying not only coal but also raw materials having poor reactivity such as coal liquefaction residue and petroleum coke. Since the softening point of coal liquefaction residue is about 200 ° C or less, the raw material melts at this temperature and expands when the temperature is further raised, so the specific surface area is much smaller than that of coal and the reactivity is poor. . According to the results of elemental analysis, coal liquefaction residue and petroleum coke have a small proportion of oxygen and hydrogen and a large proportion of carbon. When such a raw material is supplied into a high-temperature furnace, hydrogen and oxygen are quickly released from the raw material in the formulas (1) and (6) to form char, but since the proportion of oxygen and hydrogen is small, char is It becomes a char with a small specific surface area, that is, poor reactivity. However, as described above, when gasifying various raw materials, simply mixing raw materials having different properties has low efficiency, and in some cases, the gasifier may not operate normally. For example, since the coal liquefaction residue has a softening point of about 200 ° C. or lower as described above, the raw material adheres to the furnace wall in an atmosphere with a small amount of oxidizer, where it melts and softens to remove volatile components and carbonize. , A large carbon flower may be formed on the furnace wall and block the tip of the burner installed on the same stage. FIG. 6 shows the test results regarding the adhesion of coal liquefaction residue to the furnace wall. This is a study of adhesion by changing the amount of oxidizer and the temperature in the gasification furnace. The adhesion of the raw material to the furnace wall cannot be weakened unless the temperature inside the furnace is raised and the oxidizer / raw material supply weight ratio is raised.
Therefore, in the case of gasifying such a raw material, if a large amount of oxidant is supplied in an attempt to eliminate the adherence of the raw material on the wall of the gasification furnace, the produced gas will have no calorific value such as water (H ₂ O) and carbon dioxide. The proportion of (CO ₂ ) will increase. Therefore, when trying to increase the reactivity of a raw material such as coal liquefaction residue and mixing highly reactive coal and supplying it to the furnace, the oxidizer reacts with the highly reactive coal first, so that the reactivity is poor. The nature of the raw material cannot be changed. The object of the present invention is to eliminate the above-mentioned drawbacks of the prior art,
Even if you use raw materials with different properties, especially those with poor reactivity,
It is to provide a gasification apparatus and an operation method capable of obtaining high gasification efficiency.

[Means for Solving the Problems]

The above object is achieved by the configurations described below. That is, in a gasification apparatus equipped with two or more stages of burners for ejecting the carbon fine powder raw material together with oxidizers such as oxygen and air in the gasification reaction region of the carbon fine powder raw material, the carbon fine powder raw material having different properties for each stage burner. Is provided, and the carbon fine powder raw material supply line system for each stage of the burner is a fine powder raw material gasifier equipped with a supply line capable of mutually exchanging the raw materials. Further, in the above fine powder raw material gasifier, at least the burner at the lowermost stage of the carbon fine powder raw materials having different properties is supplied with the carbon fine powder raw material having inferior reactivity together with the oxidant, and at least the burner at the uppermost stage is made to have a high reactivity. It is a method of operating a gasifier that supplies a good carbon fine powder raw material. Anhydrous / ashless base elemental analysis (hydrogen + oxygen) / low carbon value raw material or highly caking raw material is used as a carbon fine powder raw material with poor reactivity. A raw material having a high (hydrogen + oxygen) / carbon value or a raw material having a low caking property in the ashless base elemental analysis may be used. When using carbon fine powder raw materials having different caking properties,
Operation to supply raw material with high caking property during steady operation, and to supply burner with low caking property to burner at least in the lowest stage instead of raw material with high caking property only when starting and stopping the fine powder material gasifier The method may be adopted.

[Action]

As described above, in the method of gasifying the carbon fine powder raw material by the gasification reaction of two or more stages, the gasification furnace is heated to a temperature at which the ash content of the raw material is melted by increasing the supply amount of the oxidizer in the lower burner more than in the upper stage. On the other hand, in the upper burner, the oxidizer is distributed in a small amount in the upper burner to convert it into char with high activity, and it is reacted with CO ₂ and H ₂ O produced in the lower burner to produce gasification reaction into CO and H _2. It is something that is going to be done. Anhydrous and ashless-based elemental analysis generally indicates that the thermal decomposition of carbon fine powder raw materials generally releases compounds containing hydrogen and oxygen, such as hydrogen and methane, at the initial stage of thermal decomposition. If so, the higher the (H + O) / C in the anhydrous / ashless elemental analysis, the higher the proportion of the compound containing hydrogen atoms and oxygen atoms released from the raw material. That is, it is converted into char having a large specific surface area. Therefore, a raw material with poor reactivity is supplied to the lower burner that distributes a large amount of the oxidizer and raises the ambient temperature above the melting point of ash.First, CO ₂ and H ₂ O are generated from the carbon fine powder raw material, and the lower burner is generated. A high gasification efficiency can be obtained by supplying a highly reactive raw material without distributing a small amount of oxidant to the upper burner in order to react the CO ₂ and H ₂ O generated in step ₂ with char. Of. The same applies to carbon fine powder raw materials having different caking properties.
A raw material with a high caking property, that is, a high Button index is supplied to the lower burner that distributes a large amount of oxidizer, and the raw material is burned as much as possible to prevent the raw material from adhering to the furnace wall, and at the same time CO ₂ and H ₂ O is produced, and CO ₂ and H ₂ O are produced to produce an active char in the upper burner to which the raw material having low caking is supplied. At this time, since the raw material having low caking property is supplied to the upper burner, even if the distribution amount of the oxidizer is reduced, the raw material does not adhere to the furnace wall and a high carbon gasification rate can be obtained. Further, when starting or stopping the carbon fine powder raw material gasifier where the furnace wall temperature is lowered, the raw material having low caking property can be supplied to the lower burner to prevent the raw material from adhering to the furnace wall.

【Example】

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing an embodiment of the gasifier of the present invention. Generally, the gasification furnace is a pressurizing device in order to make the device compact.When using carbon fine powder raw material, the atmospheric hopper 10 and the two pressurizing hoppers 20 for the upper burner 61 and the lower burner 62, respectively. and
The carbon fine powder raw material is supplied to the burner by the carrier gas such as nitrogen gas introduced from the carrier gas line 51 in the ejector 50 downstream of the hopper 40, which is supplied in a fixed amount through the feeder 30. That is, in the present invention, separate supply systems are installed for the upper burner 61 and the lower burner 62, respectively. Also, from the pressure hopper 30 'for the upper burner,
The raw material for the upper burner can also be supplied to the feeder 40 for the lower burner through the line 36 provided with the valve 34. Gasifier 60 upper burner 61 and lower burner 62
Oxidizers such as oxygen and air are sent to the respective units via supply lines 63 and 64. The carbon fine powder raw material is gasified in the gasification chamber 65, and the produced gas is discharged from the line 69 at the upper end of the gasifier 60. By distributing the supply amount of the oxidant to the lower burner 62 more than that of the upper burner 61, the temperature of the lower portion of the gasification chamber 65 is raised to the temperature at which the slag melts. The generated slag is cooled by the cooling water 66 at the bottom of the gasifier 60 and discharged through the hopper 68. An example of the driving method of the present invention is shown in FIG. Upper burner
61 is a raw material having a high (H + O) / C ratio by elemental analysis on an anhydrous / ashless basis, and the lower burner 62 is a coal having a low analysis value. In a gasifier 60 in which two burners with different functions are installed in the furnace to carry out a gasification reaction, in the lower burner 62, the oxidizer is distributed in the upper burner 61.
By increasing the amount, the ash content of the raw material is raised to a temperature at which it melts, and the upper burner 61 distributes the oxidizing agent in a small amount to convert the carbon fine powder raw material into char rich in activity, and the CO produced in the lower burner 62.
It is intended to carry out a gasification reaction of CO and H ₂ by reacting with ₂ and H ₂ O. Therefore, the lower burner
The function of 62 is to form a high temperature atmosphere, and since a large amount of the oxidant is distributed, whether or not the reactivity of the raw material is good does not matter. On the other hand, since the function of the upper burner 61 is to generate active char and to carry out gasification reaction, it is possible to increase the gasification efficiency by generating char with the best reaction. An active char is a char with a large specific surface area, and a compound having elements of H and O is released by thermal decomposition. Therefore, it is (H + O) / C in anhydrous / ashless base elemental analysis. The raw material of high quality is supplied to the upper burner 61. Therefore, the lower burner 62, which distributes a large amount of oxidizer and raises the ambient temperature above the melting point of ash, supplies a raw material with poor reactivity, and the upper burner that generates active char by distributing a small amount of oxidizer. By supplying a highly reactive raw material to 61, high gasification efficiency can be obtained. Table 1 shows the test results of the gasification method of the present invention, and Table 2 shows the properties of the raw materials used. In Table 1, the raw materials added, for example, A + B or C + D, is a raw material prepared by mixing raw materials having different properties at a ratio of 1: 1. As is clear from the test Nos. 1-1 and 1-2 in Table 1, as compared with the case of mixing the raw material with high (H + O) / C and the raw material with low (H + O) / C, the raw material with high (H + O) / C was Upper burner 61
It can be seen that the gasification efficiency is improved by 4% by supplying to. Furthermore, in the case of a raw material having a caking property higher than those of Test Nos. 2-1 and 2-2, that is, a raw material having a high Button index and a raw material having a low Button index, the raw material adhered to the furnace wall of the upper burner 61 facing and melted. Although the burner outlet was blocked and could not be gasified, a gasification test could be performed by supplying a raw material with a high Button index to the lower burner 62 that distributes a large amount of oxidizer.
A high carbon gasification rate was obtained. FIG. 3 shows a method of operating a gasifier for carbon fine powder raw materials having different caking properties. As shown in FIG. 6, the raw material such as the coal liquefaction residue (raw material D in Table 2) shown in Example 1, when the temperature inside the furnace was low, the raw material ejected from the burner adhered to the furnace wall to form a large lump of carbon. To form. Therefore, the raw material having a lower caking property than the lower burner is supplied at the time of starting and before the shutdown of the gasifier where the temperature in the furnace becomes low. That is, the pressure hopper 30 shown in FIG.
The valve 31 at the outlet is closed and the valve 34 is opened to supply the raw material having low caking property to the lower burner 62. In FIG. 1, the line 36 and the valve 34 are installed in the feeder 40 for the lower burner 62 from the pressure hopper 30 'for supplying the raw material to the upper burner 61, but as shown in FIG. The same effect can be obtained by providing two groups of hoppers to be supplied to.

【The invention's effect】

According to the present invention, carbon fine powder raw materials having different properties can be gasified efficiently according to their properties and without generation of carbon flower or the like. Even for carbon fine powder raw materials with particularly low reactivity, it is possible to efficiently gasify them by combining the highly reactive carbon fine powder raw materials and the supply amount of the oxidizer for each raw material efficiently, and the coal liquefaction residue Alternatively, it can be applied to gasification of petroleum coke.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a gasifier of the present invention, FIGS. 2 and 3 are operation methods of the gasifier of the present invention, and FIG. 4 is gasification of the present invention. FIG. 5 is a schematic configuration diagram showing an embodiment of the apparatus, FIG. 5 is a schematic configuration diagram of a conventional gasification apparatus, and FIG. 6 is a diagram showing the amount of oxidizer of a highly caking raw material and the temperature in the furnace. The test results of the adhesiveness are shown below. 61 …… Upper burner, 62 …… Lower burner, 34 …… Valve,
65 ... Gasification chamber

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Isao Oyama 2-6-2 Otemachi, Chiyoda-ku, Tokyo Babcock Hitachi Ltd. (72) Inventor Yoshiki Watanabe 6-9 Takaramachi, Kure-shi, Hiroshima Babcock Hitachi Kure Factory Co., Ltd. (56) Reference JP 64-22998 (JP, A) JP 61-266491 (JP, A) JP 61-246287 (JP, A) JP 2-202993 ( JP, A)

Claims (5)

[Claims] 1. A gasifier having two or more burners for ejecting carbon fine powder raw material together with an oxidizing agent such as oxygen and air in a gasification reaction region of the carbon fine powder raw material, the burner having different properties for each stage. A fine powder raw material gasifier, characterized in that a supply line system for supplying a fine carbon raw material is provided, and the fine powder raw material supply line system for each stage of the burner is provided with a supply line capable of mutually exchanging the raw materials. 2. A raw material having poor reactivity is supplied together with an oxidant to at least the lowermost burner, and a raw material having good reactivity is supplied to at least the uppermost burner. Method for operating fine powder gasifier. 3. A raw material having poor reactivity is a raw material having a low value of (hydrogen + oxygen) / carbon in elemental analysis on an anhydrous / ashless basis,
The raw material having good reactivity is a raw material having a high value of (hydrogen + oxygen) / carbon in an element analysis on an anhydrous / ashless basis, and the method for operating a fine powder raw material gasifier according to claim 2. 4. The fine powder raw material gasifier according to claim 2, wherein the raw material having poor reactivity is a raw material having high caking property and the raw material having good reactivity is a raw material having low caking property. Driving method. 5. A raw material having a high caking property is supplied to at least the bottom burner which supplies a highly caking material during a steady operation, only when the fine powder raw material gasifier is started and stopped. 5. Feeding low raw material.
A method for operating the fine powder raw material gasifier described.