JPH09256016A - Improver for conveyability of pulverized fine coal - Google Patents

Abstract

(57) 【Abstract】 PROBLEM TO BE SOLVED: To improve the transportability of pulverized coal and enable it to be used as a blown fuel for a metallurgical furnace or a combustion furnace. We also provide pulverized coal that can prevent shelving from hanging in the hopper, blow through, and blockage of piping. SOLUTION: A compound selected from one or more of alcohols having 10 or less carbon atoms and amines having 10 or less carbon atoms has an average HGI of raw coal of 30 or more and is blown into a metallurgical furnace or a combustion furnace. Impregnated with pulverized coal that is dry in the mouth.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention improves the transportability of pulverized coal blown from the inlet of a metallurgical furnace or a combustion furnace, and makes it possible to stably blow a large amount of pulverized coal. The present invention relates to a method of operating a metallurgical furnace or a combustion furnace using the.

[0002]

In the operation of metallurgical furnaces such as blast furnaces,
The method of alternately charging coke and iron ore from the top of the furnace has been generally used, but in recent years, a part of the coke charged from the top of the furnace was replaced with pulverized coal that is inexpensive, highly combustible, and has a high calorific value. The method of substituting by blowing from the blowing port of the blast furnace together with hot air is actively used. Such a pulverized coal blowing operation method is superior in that the fuel cost can be reduced as compared with the all coke operation.

Further, coal has been reviewed as an alternative to heavy oil as a fuel for combustion furnaces such as boilers. CWM (coal-water slurry), COM (coal heavy oil mixed fuel), pulverized coal, and the like are used as coal in the combustion furnace. Among them, the pulverized coal combustion furnace particularly requires other media such as water and oil. And because it doesn't, it is getting attention. However, this pulverized coal combustion furnace also has the same problem as the use of pulverized coal in blast furnace operation.

In blowing pulverized coal, pulverized coal is produced by dry pulverization of raw coal, classification, storage / discharge in a hopper,
Follow the steps of gas transportation through piping, blowing into the metallurgical furnace or combustion furnace from the blowing port, and combustion within the metallurgical furnace or combustion furnace.The discharge of pulverized coal from the hopper and gas transportation through piping are as follows. There is a problem.

That is, the basic physical properties of the powder such as the fluidity of the pulverized coal change depending on the coal type, particle size, and water content of the pulverized coal to be discharged / transported, so that the discharge / transport situation greatly changes. For this reason, if the basic physical properties of pulverized coal are out of the optimum range, suspending and blowing through the hopper with a hopper,
This may cause pipe blockage during gas transportation, and it is difficult to continue stable pulverized coal injection for a long period of time.

In order to solve such a problem, it is considered to improve the transportability of pulverized coal, and various methods have been proposed in the past. For example, char in pulverized coal 5-20
% Mixing (Japanese Patent Laid-Open No. 4-268004), inert in coal (MICLINIT prescribed by JIS M8816-1979,
1/3 Semi-Fujinit, Fujinit and mineral substances) After adjusting the amount of components, finely pulverized (JP-A-5-95)
18, JP-A-5-25516, JP-A-5-222415
Gazette), the coal type of pulverized coal to be blown is limited so that the fluidity index is equal to or higher than the reference value of the blast furnace (Japanese Patent Laid-Open No. 4-224610), and the friction coefficient between the pulverized coal and the pipe is adjusted (special feature). (Kaihei 5-214417), and control the water content in the pulverized coal to an appropriate value (Japanese Patent Laid-Open No. 5-78675).
And the like. Further, as a method for improving the pulverization efficiency of pulverized coal, a method of adsorbing a dispersant (Japanese Patent Laid-Open No. 63-224744).
However, this method does not mention the transportability of pulverized coal.

[0007]

However, in the above-mentioned method, the kinds of coal that can be used for blowing pulverized coal are limited, the hanging and blowing through of the hopper in the hopper, and the clogging of the pipe are not sufficiently solved, and the control is not possible. However, there is a problem in that the equipment and facilities are expensive, and a method that is practically satisfactory is not provided.

Further, for example, in the current method of operating a blast furnace,
The amount of pulverized coal blown from the blowing port is about 50 to 250 kg / pig of pig iron, but it is desirable to further increase the amount of pulverized coal blown from the viewpoint of cost. However, since the pulverized coal is not always sufficiently conveyed by the above method, it is not possible to significantly improve the blowing amount of the pulverized coal.

Therefore, the object of the present invention is to solve the above-mentioned problems in the conventional method and to improve the transportability of pulverized coal.
The purpose is to remove restrictions on coal types, prevent pipe blockages and hanging in hoppers, and enable stable large-scale injection of pulverized coal.

[0010]

Means for Solving the Problems As a result of intensive studies aimed at achieving the above object, the present inventors have found that an organic compound having a polar group and substantially soluble in water has an average HGI of 30 or more in raw coal. It has been found that the transportability of such pulverized coal is dramatically improved by impregnating it with the pulverized coal of No. 3, and has completed the present invention.

That is, the present invention comprises one or two or more alcohols and / or amines having a carbon number of 10 or less contained in a compound, and blowing of a raw coal into a metallurgical furnace or a combustion furnace having an average HGI of 30 or more. Pulverized coal transportability improver characterized by being used for pulverized coal that is dry in the mouth,
And a pulverized coal comprising such a transportability improver and fine pulverized coal. The present invention also provides a method for operating a metallurgical furnace or a combustion furnace using such a transportability improver and fine pulverized coal.

The compound used in the present invention comprises one or more alcohols and / or amines having 10 or less carbon atoms contained in the compound. Alcohols and / or amines having 11 or more carbon atoms contained in the compound are not preferable because of the effect of improving transportability.

Examples of the pulverized coal transportability improver selected from one or more alcohols and / or amines having 10 or less carbon atoms contained in the compound include compounds having the following structures.

[0014]

Embedded image

In the above formula, the number of carbon atoms contained in the compound is 1.
It is 0 or less, and R ₁ , R ₂ and R ₃ are H, a C _{1 to} C ₉ linear or branched alkyl group or alkenyl group, a phenyl group or a phenyl group substituted with an alkyl group. Preferably, the compound contains 6 or less carbon atoms, R ₁ ,
R ₂ and R ₃ are H or a C _{1 to} C ₅ linear or branched alkyl group or alkenyl group, more preferably 4 or less carbon atoms contained in the compound, and R ₁ , R ₂ and R ₃ is H or
A straight-chain or branched alkyl or alkenyl group of C ₁ -C _3.

[0016]

Embedded image

In the above formula, the number of carbon atoms contained in the compound is 1.
It is 0 or less, and R ₁ , R ₂ , R ₃ and R ₄ are H, a C _{1 to} C ₈ linear or branched alkyl group or alkenyl group, a phenyl group or a phenyl group substituted with an alkyl group. Preferably, the number of carbon atoms contained in the compound is 6 or less,
R ₁ , R ₂ , R ₃ and R ₄ are H and C _{1 to} C ₄ linear or branched alkyl groups or alkenyl groups, and more preferably the number of carbon atoms contained in the compound is 4 or less, and ₁ , R ₂ , R ₃ ,
R ₄ is H, a C ₁ -C ₂ linear or branched alkyl group or alkenyl group.

[0018]

Embedded image

In the above formula, the number of carbon atoms contained in the compound is 1.
0 or less, R ₁ , R ₃ , R ₄ and R ₅ are H, C _{1 to} C ₈ linear or branched alkyl group or alkenyl group, phenyl group or phenyl group substituted with alkyl group, R ₂ : C ₂ or less alkylene group or alkenylene group. Preferably
R ₂ is —CH ₂ —, R ₄ and R ₅ are H, R ₁ and R ₃ are H or C ₂ or less alkyl or alkenyl groups.

(4) Triol or higher polyol. For example, glycerin, polyglycerin, sorbitol, martinol, glucose, fructose, pentaerythritol, trimethylolpropane, polyethylene glycol, polypropylene glycol, etc.

[0021]

Embedded image

In the above formula, the number of carbon atoms contained in the compound is 1.
0 or less, and at least one of R ₁ , R ₂ and R ₃ is C ₁
To C ₁₀ linear or branched hydroxyalkyl group or hydroxyalkenyl group, and the rest are H or C _{1 to} C ₉ linear or branched alkyl group or alkenyl group. Preferably, the compound contains 8 or less carbon atoms, and at least one of R ₁ , R ₂ and R ₃ is a C _{1 to} C ₈ linear or branched hydroxyalkyl group or hydroxyalkenyl group. And the remainder is H or a C ₁ -C ₇ linear or branched alkyl or alkenyl group. More preferably, the number of carbon atoms contained in the compound is 6 or less,
At least one of R ₁ , R ₂ and R ₃ is a C _{1 to} C ₆ linear or branched hydroxyalkyl group or hydroxyalkenyl group, and the rest is H or C _{1 to} C ₅ linear or branched. Is an alkyl group or an alkenyl group.

[0023]

Embedded image

In the above formula, the number of carbon atoms contained in the compound is 1
0 or less, at least one of R ₁ , R ₂ , R ₃ , and R ₄ is a C _{1 to} C ₉ linear or branched hydroxyalkyl group or hydroxyalkenyl group, and the remainder is H or C _1. it is a linear or branched alkyl or alkenyl group -C _9. R ₅ is an alkylene group having C ₂ or less or an alkenylene group. Preferably, the number of carbon atoms contained in the compound is 8 or less, and at least one of R ₁ , R ₂ , R ₃ and R ₄ is C _{1 to} C _7.
Is a linear or branched hydroxyalkyl group or hydroxyalkenyl group, and the rest is H or a C _{1 to} C ₇ linear or branched alkyl group or alkenyl group, and R ₅ is
It is an alkylene group having C ₂ or less or an alkenylene group. More preferably, the number of carbon atoms contained in the compound is 6 or less, and at least one of R ₁ , R ₂ , R ₃ and R ₄ is a C _{1 to} C ₅ linear or branched hydroxyalkyl group or A hydroxyalkenyl group, the remainder being H or a C _{1 to} C ₅ linear or branched alkyl or alkenyl group, and R ₅ being C ₂
The following are alkylene groups or alkenylene groups.

The operation method of the metallurgical furnace or the combustion furnace using the transportability improver of the present invention is 0.01% by weight or more to 30% by weight with respect to the pulverized coal blown from the blowing port of the metallurgical furnace or the combustion furnace.
% By weight or less, preferably 0.05% by weight or more and 15% by weight
The following transportability improver is added to pulverized coal. When the content of the organic compound is 0.01% or more, it is more preferable than the effect of improving the transportability, and even if it is added in an amount of more than 30% by weight, the effect corresponding to the added amount is not improved and it is economically disadvantageous. .

The pulverized coal which is the object of the present invention is pulverized coal whose raw coal has an average HGI of 30 or more and is dried at the injection port of a metallurgical furnace or a combustion furnace. Here, "dried" means that the amount of water is 0.1% by weight to 30% by weight according to the dry weight loss measurement method defined in JIS M8812-1984. Pulverized coal with a high water content is not suitable as a fuel for blowing in a metallurgical furnace or a combustion furnace.

Although pulverized coal having an average HGI of 30 or more of such raw coal has poor transportability, the transportability improving method of the present invention enables smooth transport of such pulverized coal. Furthermore, the present invention is also effective for pulverized coal having an average HGI of 50 or more of raw coal, which is considered to be extremely difficult to transport by gas using the present technology.

Here, "HGI" means "Hardgrov"
e Grinding Index "(grinding power index), which is an index of coal crushing resistance defined in ASTM D409.

As a result of investigations, the present inventors have found that it is necessary to add the above-mentioned transportability improver in order to solve the above-mentioned problem of pulverized coal.

As an index of the transportability of the pulverized coal, the fluidity index and the pressure loss in the pipe transportation test described in detail in Examples described later were used. The fluidity index can simulate discharge characteristics in a hopper, and the pressure loss can simulate flow characteristics in a pipe during gas transportation. In order to improve transportability, it is necessary to improve the fluidity index by 3 points or more and reduce the pressure loss by 3 mmH ₂ O / m or more. Also, for pulverized coal that has a very poor transportability that causes blockage in an actual machine, the fluidity index is 40 or more and the pressure loss is 16
It is preferable to set it to mmH ₂ O / m or less.

It is preferable to disperse these as they are or to dissolve them in a solvent at an appropriate concentration to dilute the concentration and to disperse them. In that case, a concentration of 1% by weight or more is more convenient for drying the solvent.

[0032]

BEST MODE FOR CARRYING OUT THE INVENTION The transportability improver of the present invention exhibits the same effect when added at any time before crushing from raw coal to pulverized coal, during crushing, after crushing, before drying, and after drying. However, it is preferable to add it before or / and during the pulverization. Further, the particle size of the pulverized coal to be the target is not particularly limited either, but from the effect of improving the transportability, 106 of the pulverized coal after pulverization is used.
It is preferable that the proportion of μm or less is 10% by weight or more. In the case of pulverized coal in which the proportion of particles of 106 μm or less of pulverized coal after pulverization is 10% by weight or less, high transportability is obtained as compared with pulverized coal of which the proportion of particles of 106 μm or less in pulverized coal is 10% by weight or more. Therefore, the effect obtained by using the method for improving transportability of the present invention is smaller.

As a metallurgical furnace and a combustion furnace to which the present invention is applied, a furnace using pulverized coal as a fuel and / or a reducing agent (blast furnace, cupola, rotary kiln, smelting reduction furnace, cold iron source melting furnace, boiler, etc.) And a carbonization device using pulverized coal (for example, fluidized bed carbonization furnace, gas reforming furnace, etc.).

[0034]

EFFECTS OF THE INVENTION According to the present invention, by adding a transportability improver, the transportability of pulverized coal which has an average HGI of raw coal of 30 or more and is dried at the inlet of a metallurgical furnace or a combustion furnace is improved. Therefore, a large amount of transportation of such pulverized coal can be achieved. Further, by carrying the method for improving the transportability of the present invention on coal having poor transportability, the transportability can be improved and a large amount can be transported, so that the types of coal that can be used for blowing pulverized coal can be expanded.

At the same time, since the pulverized coal to be blown from the blowing port treated by the method for improving the transportability of the present invention has a good fluidity, it is possible to prevent hanging in the hopper and further to suspend it from the hopper. It is possible to greatly reduce the temporal change of the cutout amount and the deviation of the distribution amount.

[0036]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

Examples 1-43 and Comparative Examples 1-8 [1] Crushing of raw coal and adjustment of pulverized coal for evaluation <Addition before crushing> The raw coal shown in the table is dried to a water concentration of 0.1% by weight. 2. A predetermined amount of dried raw coal is sampled.

3. The transportability improver is added so that the set additive concentration (converted to dry coal) is achieved. 4. If necessary, water is added so that the water content becomes the set water content at the time of grinding (if the additive is an aqueous solution, the water content is subtracted). 5. If necessary, dry until the set water content during grinding is reached.

Grind so that the ratio of pulverized coal of 6.106 μm or less reaches a set value. The crusher at this time is a small crusher SCM-40A (manufactured by Ishizaki Electric). 7. The pulverized coal is dried or humidified so that the water content is 0.5% by weight.

<Addition after grinding> 1. The raw coal shown in the table is dried to a water concentration of 0.1% by weight.

2. A predetermined amount of dried raw coal is sampled.

3. If necessary, water is added so that the water content becomes the set water content at the time of grinding (if the additive is an aqueous solution, the water content is subtracted). 4. If necessary, dry until the set water content during grinding is reached.

Grind so that the ratio of pulverized coal having a particle size of 5.106 μm or less reaches a set value. The crusher at this time is a small crusher SCM-40A (manufactured by Ishizaki Electric). 6. The transportability improver is added so that the set additive concentration (converted to dry coal) is achieved. 7. Pulverized coal and additives are mixed by hand shaking in a polybin so as to be uniform. 8. The pulverized coal is dried or humidified so that the water content is 0.5% by weight.

Here, the ratio of particles of 106 μm or less in the pulverized coal after pulverization is defined by the following formula.

[0045]

[Equation 1]

The sieve is an industrial sieve (made by Iida Kogyo Co., Ltd.) having an opening of 106 μm and a wire diameter of 75 μm defined by JIS Z 8801, and the vibrator is a micro type electromagnetic vibration sifter M-2 type (Tsutsui physicochemical equipment). (Manufactured by KK) was used with a vibration intensity of 8 (vibration adjusting scale) and a vibration time of 2 hours.

[2] Raw Coal Used for Evaluation The following two types of raw coal having different HGIs were used for evaluation. a charcoal: HGI48 b charcoal: HGI55 Among these, the b char of HGI55 or higher has troubles such as pipe clogging in the actual machine, hanging in the hopper, etc., and the current technology is to produce pulverized coal for combustion furnace or metallurgical furnace blowing. It cannot be used as raw coal.

<Flowability Index Measuring Method> The fluidity index is an index for evaluating the fluidity of the powder, and the four factors of the powder (repose angle, compressibility, spatula angle, cohesion degree) are indexes. It is obtained from the sum of each index. For details on the measurement method and index of each factor, refer to 151-in "Handbook of Powder Engineering" (edited by Japan Society of Powder Engineering, published by Nikkan Kogyo in 1987).
It is described on page 152. In addition, the measuring method of each factor is described below. 1. Angle of repose: The powder is passed through a standard sieve (25 mesh) and further injected through a funnel onto a disk having a diameter of 8 mm, and the inclination angle of the formed sedimentary layer is measured. 2. Compressibility: Cylindrical container for filling powder (volume 100c
m ³ ), the degree of compression is calculated from the bulk density ρ _s (g / cm ³ ) in the loosely packed state and the dense packing density ρ _c (g / cm ³ ) after tapping a certain number of times (180 times). ψ (%) is calculated by the following formula. ψ = (ρ _c −ρ _s ) × 100 / ρ _c (%) 3. Spatula angle: A spatula (spatula) with a constant width (22 mm) is inserted into the accumulated powder, and the spatula is lifted and the inclination angle of the powder placed on the spatula is measured. Next, a slight impact is applied to the spatula, this angle is measured again, and the average value of these two is taken as the spatula angle. 4. Cohesion degree: Three kinds of sieves with different mesh openings (each sieve is 60, 100, 200mesh from the upper stage) are piled up, 2 g of powder is placed on the uppermost stage, and then these are vibrated at the same time, and left on each sieve after vibration is stopped. Weighing the amount of the powder, (the amount of powder of the upper sieve / 2g) × 100, (the amount of powder of the intermediate sieve / 2g) ×
100 x 3/5, and (amount of powder in the lower sieve / 2g) x
It is calculated by summing the three calculated values of 100 × 1/5. Incidentally, in the case of pulverized coal as used in the present invention, there is no difference in the amount of pulverized coal remaining in each sieve, it is difficult to calculate the cohesion, in the present invention, the angle of repose, the degree of compression, the spatula angle of The liquidity index was evaluated from the three total points.

<Piping Transport Characteristic Measuring Method> “CAMP-I
SIJ Vol. 6 ”(1993), page 91, in accordance with the method described in detail, the pipe transportation characteristics were evaluated by measuring the pressure loss with the apparatus of FIG. 1, 1 is pulverized coal, 2 is a table feeder, 3 is a flow meter, 4 is a pipe diameter 1
2.7mm horizontal tube, 5 means cyclone. This device measures the pressure loss between the pressure measurement holes (P ₁ , P ₂ ) by transporting the pulverized coal 1 discharged from the powder feeder 2 by a carrier gas. The experimental conditions were as follows. Pulverized coal supply rate 0.8 kg / min Carrier gas Nitrogen (N ₂ ) Carrier gas amount 4 Nm ³ / h (67 liters / min) Transport time 6 minutes Evaluation is as follows. 1. Pressure Loss The pressure gauges P ₁ and P ₂ sample data at 500 Hz. The pressure loss is P ₁ during the transportation time (6 minutes).
Given by the overall average of P ₂ .

[0050]

[Equation 2]

The results are shown in Tables 1-7.

[0052]

[Table 1]

[0053]

[Table 2]

[0054]

[Table 3]

[0055]

[Table 4]

[0056]

[Table 5]

[0057]

[Table 6]

[0058]

[Table 7]

In Tables 1 to 7, "106 μm or less (%)" indicates the proportion (% by weight) of particles having a particle size of 106 μm or less in the pulverized coal. Table 1 shows Comparative Examples 1 and 2 in the case of only raw coal. From Table 1, the fluidity index that can be used without problems in an actual machine is 40 or more, and the pressure loss is 16.0 m.
It can be seen that it is below mH ₂ O / m. Further, Table 2 shows the influence of the ratio of pulverized coal having a particle size of 106 μm or less and the addition timing of the additive when the b coal is used. If the proportion of pulverized coal having a particle size of 106 μm or less is 10% or more, preferably 40% or more, the effect of the additive is exerted and the effect of the additive is greater before the crushing than when after the crushing. Recognize.

Table 3 shows the effect of the concentration of the transportability improver added. It can be seen that the addition concentration must be 0.01% by weight or more, preferably 0.05% by weight or more. Examples of the transportability improver composed of various compounds are shown in Table 4 and thereafter.

Further, as shown in Table 7, the number of carbon atoms is 10
It can be seen that in Comparative Examples 6 to 8 in which the compounds exceeding 5 are used, sufficient improvement of the fluidity index and reduction of pressure loss are not achieved.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an apparatus used for measuring pipe transportation characteristics.

[Explanation of symbols]

 1: Pulverized coal 2: Table feeder 3: Flow meter 4: Horizontal pipe 5: Cyclone

Front page continued (72) Inventor Yoshio Kimura 1 Kanazawa-machi, Kakogawa-shi, Hyogo Prefecture Kamido Steel Works, Ltd. Kakogawa Steel Works (72) Inventor Tsuneo Kamijo 1-kanazawa-machi, Kakogawa-shi, Hyogo Kadogawa Steel Works Kakogawa Inside the steelworks (72) Kenichi Miyamoto 1334 Minato Minato, Wakayama City, Wakayama Prefecture Kao Co., Ltd. (72) Inventor Takashi Matoba 1334 Minato Minato, Wakayama City, Wakayama Prefecture (72) Inventor Hideo Ohashi Wakayama Prefecture 1334 Minato Minato, Wakayama City Research Center, Kao Corporation (72) Inventor Takehiko Ichimoto 1334 Minato Minato City, Wakayama City, Wakayama Prefecture

Claims (10)

[Claims] 1. A fine powder comprising a compound selected from one or more of an alcohol having a carbon number of 10 or less and an amine having a carbon number of 10 or less, which is used for a pulverized coal having an average HGI of raw coal of 30 or more. A pulverized coal transportability improving agent, which is a charcoal transportability improving agent, wherein the pulverized coal to which the transportability improving agent is applied is dried at a blowing port of a metallurgical furnace or a combustion furnace. 2. The pulverized coal transportability improver according to claim 1, which is added to the pulverized coal before and / or during pulverization. 3. The ratio of particles having a particle size of 106 μm or less after pulverization of the pulverized coal is 10% by weight or more.
The pulverized coal transportability improver described. 4. The surface of a pulverized coal obtained by crushing raw coal having an average HGI of 30 or more is selected from one or more alcohols having 10 or less carbon atoms and amines having 10 or less carbon atoms. Pulverized coal obtained by depositing a compound as described above and dried at a blowing port of a metallurgical furnace or a combustion furnace. 5. The organic compound is used before pulverization of raw coal and / or
Alternatively, the pulverized coal according to claim 4, which is added during pulverization. 6. The pulverized coal according to claim 4, wherein the proportion of particles having a particle size of 106 μm or less in the pulverized coal is 10% by weight or more. 7. The surface of pulverized coal obtained by crushing raw coal having an average HGI of 30 or more is selected from one or more alcohols having 10 or less carbon atoms and amines having 10 or less carbon atoms. The method for operating a metallurgical furnace or a combustion furnace, comprising: blowing pulverized coal obtained by adhering a compound as described above, from a blowing opening of the metallurgical furnace or the combustion furnace in a dry state. 8. The operation of a metallurgical furnace or a combustion furnace according to claim 7, wherein the pulverized coal to which the compound is attached in an amount of 0.01% by weight or more and 30% by weight or less (equivalent to dry coal) is blown from a blowing port. Method. 9. The method for operating a metallurgical furnace or a combustion furnace according to claim 7, wherein the compound is added before and / or during the pulverization of raw coal. 10. Particle size 106 in pulverized coal after pulverization of raw coal
8. The ratio of particles having a size of μm or less is 10% by weight or more.
10. A method of operating a metallurgical furnace or a combustion furnace according to any one of claims 9 to 10.