JP2015155569A - Method of preparing blast furnace blow coal, blast furnace blow coal and utilization thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of preparing blast furnace blow coal enabling acquisition of blast furnace blow coal which suppresses poor flowing of slag within the blast furnace body even when the blowing amount into the blast furnace body is increased.

SOLUTION: A method of preparing blast furnace blow coal comprises analyzing the ash content of coal as raw coal and weights % of Al, Si, Ca and Mg in the ash (first step S1), calculating the melting point of the ash of the coal on the basis of data obtained by the analysis (second step S2), selecting metal species to be carried in the coal so that the melting point of the ash of the coal is 1,200-1,400°C and calculating the carried amount (third step S3), causing the carried amount of the metal to be carried in the coal by the ion exchange method (fourth step S4) and dry-distilling the coal obtained in the fourth step (fifth step S5).

COPYRIGHT: (C)2015,JPO&INPIT

Description

  The present invention relates to a method for preparing blast furnace blown coal, blast furnace blown coal, and a method for using the same.

  The blast furnace equipment is charged with iron ore, limestone and coke raw materials from the top of the blast furnace main body, and hot blast and auxiliary fuel (pulverized coal) as hot air and auxiliary fuel from the tuyere near the side of the blast furnace main body. ) Can be produced from iron ore.

  By the way, in order to stably operate the blast furnace facility, adhesion of blast furnace blown coal ash or blockage due to the blast furnace blown coal ash is suppressed in a path where the blast furnace blown coal reaches the tuyere of the blast furnace body. It is demanded.

  For example, the softening point of ash in pulverized coal is measured in advance, and the ash softening point of pulverized coal is less than 1300 ° C., and a CaO-source fossilizing agent such as limestone or serpentine or other pulverized coal is used. The required amount determined based on the softening point of the ash is adjusted to adjust the softening point of the ash in the pulverized coal to 1300 ° C or higher, and then only the pulverized coal whose ash softening point in the pulverized coal is 1300 ° C or higher is used. It has been proposed to improve the flammability of blast furnace-blown coal by blowing into the interior of the blast furnace body from the tuyere (see, for example, Patent Document 1 below).

In addition, for example, a blast furnace operation method in which any one or more of CaO-based, MgO-based, and SiO ₂ -based fluxes are blown into a blast furnace from a tuyere has been proposed (see, for example, Patent Document 2 below). ).

JP-A-5-156330 JP-A-3-291313

  However, in the technique described in Patent Document 1, since the particle size of calcium oxide added as the slagging agent is large (about 10 μm in fine powder), it takes time to equalize with the slag in the blast furnace. Even when a large amount of blast furnace-blown coal is blown, it may be difficult to obtain the effect of increasing the softening point of the blast furnace-blown coal due to the addition of the slagging agent.

  Since only the blast furnace operation method that ensures the fluidity of the Bosch slag generated in the blast furnace by setting the viscosity at 1450 ° C. to 10 poise or less is described in Patent Document 2, to the tuyere of the blast furnace body It may not be possible to suppress the adhesion of blast furnace blown coal ash or the blockage caused by blast furnace blown coal ash on the route to reach.

  For this reason, the present invention has been made to solve the above-described problem, and even if the amount of injection into the blast furnace body is increased, the flow failure of the slag in the blast furnace body occurs. It aims at providing the preparation method of the blast furnace injection coal which can obtain the difficult blast furnace injection coal, the blast furnace injection coal, and its utilization method.

The method for preparing blast furnace blown coal according to the first invention for solving the above-described problems is as follows.
A first step of analyzing coal ash at the time of coal raw coal and weight% of Al, Si, Ca, Mg in the ash;
A second step of deriving the ash melting point of the coal based on the data obtained by analysis;
Based on the data obtained in the first step and the second step, the metal species to be supported on the coal is selected so that the melting point of the ash of the coal is 1200 to 1400 ° C., and the supported amount A third step of deriving
A fourth step of supporting the amount of the metal on the coal by an ion exchange method;
And a fifth step of carbonizing the coal obtained in the fourth step.

The method for preparing blast furnace blown coal according to the second invention for solving the above-described problem is a method for preparing blast furnace blown coal according to the first invention described above,
The metal is at least one of calcium and magnesium.

The method for preparing blast furnace blown coal according to the third invention for solving the above-described problem is a method for preparing blast furnace blown coal according to the first or second invention described above,
In the fifth step, the coal is heat-treated at 350 to 550 ° C. to have a residual volatile content of 15 to 35%.

The method for preparing blast furnace blown coal according to the fourth invention for solving the above-described problem is a method for preparing blast furnace blown coal according to any one of the first to third inventions described above,
The amount of the metal supported on the coal is 0.2 to 1.55 in a weight ratio of (CaO + MgO) / SiO ₂ .

The method for preparing blast furnace blown coal according to the fifth invention for solving the above-described problem is a method for preparing blast furnace blown coal according to the fourth invention described above,
The amount of the metal supported on the coal is (CaO + MgO) / SiO _{2 in} a weight ratio of 0.25 to 1.4.

The method for preparing blast furnace blown coal according to the sixth invention for solving the above-described problem is a method for preparing blast furnace blown coal according to the fifth invention described above,
The amount of the metal supported on the coal is 0.35 to 1 in a weight ratio of (CaO + MgO) / SiO ₂ .

  A blast furnace blown coal according to a seventh invention for solving the above-described problems is obtained by the method for preparing a blast furnace blown coal according to any one of the first to sixth inventions described above.

  The utilization method of the blast furnace injection coal which concerns on 8th invention which solves the subject mentioned above is the blast furnace injection obtained by the preparation method of the blast furnace injection coal which concerns on any one invention of the 1st thru | or 6 mentioned above. Charcoal is blown from the tuyere into the blast furnace body of the blast furnace facility.

  According to the present invention, the metal supported on the coal is nanoparticulate and dispersed evenly in the coal, accelerating the mixing and homogenization of the combustion ash, the nanoparticulated metal and the slag in the blast furnace body, Even if the amount of injection into the blast furnace body is increased, blast furnace injection charcoal that is less likely to cause poor flow of slag in the blast furnace body can be obtained.

It is a flowchart figure showing the procedure of the preparation method of blast furnace injection charcoal concerning one embodiment of the present invention. The total weight of Al, Si, Ca, Mg oxide in the ash content of coal used in the method for preparing blast furnace blown coal according to one embodiment of the present invention is 100% by weight, and the Al ₂ O ₃ content is 20% by weight. 4 is a quaternary phase diagram of SiO ₂ —CaO—MgO-20% Al ₂ O ₃ . One used in the preparation method of embodiment blast blowing coal according to (CaO + MgO) / SiO ₂ weight ratio and the relationship between the ash melting point of the present invention is a graph showing.

  Embodiments of a method for preparing blast furnace blow coal, a blast furnace blow coal and a method for using the same according to the present invention will be described with reference to the drawings. However, the present invention is limited only to the following embodiments described with reference to the drawings. It is not something.

  One embodiment of the preparation method of blast furnace injection coal concerning the present invention, blast furnace injection coal, and its utilization method is described based on Drawing 1-3.

  The blast furnace injection coal according to the present embodiment is blast furnace injection coal that is injected from the tuyere into the inside of the blast furnace body of the blast furnace facility, and as shown in FIG. At the same time, the weight percent of Al, Si, Ca, Mg in the ash content of the coal is analyzed (first step S1), and the ash melting point of the coal is derived based on the data obtained by the analysis (second step). S2), based on the derived ash melting point of the coal, the metal species to be supported on the coal is selected, the amount of the metal supported on the coal is derived (third step S3), and the third Based on the data obtained in step S3, the supported amount of the metal is supported on the coal by an ion exchange method (fourth step S4), and the coal supporting the metal (hereinafter referred to as metal-supported coal) is used. Easy to prepare by dry distillation (fifth step S5) Kill.

  In the first step S1, the composition of the ash content of the raw coal is the data that is most basically used as the quality of the coal (raw coal). It is possible to use data obtained by industrial analysis carried out, for example as defined in JIS M8812 (2004).

  In the first step S1, the weight% of Al, Si, Ca, Ma in the ash content of coal is the data that is most basically used as the quality of coal (raw coal), For example, a method for analyzing metals in exhaust gas (method using ICP (High Frequency Inductively Coupled Plasma)) defined in JIS K 0083, a method for analyzing coal ash and coke ash defined in JIS M 8815 Can be used.

  As the coal (raw coal) to be analyzed in the first step S1, for example, lignite, subbituminous coal, etc., low-grade coal (oxygen) generally containing a lot of carboxy groups (—COOH) and hydroxy groups (—OH). It is preferable to use an atomic content ratio (dry base): more than 18% by weight and an average pore diameter: 3 to 4 nm.

In the second step S2, the ash melting point of the coal is determined based on the data obtained in the first step S1 (weight% of Al, Si, Ca, Mg in the coal ash). Al, Si, Ca, Mg oxide is 100% by weight, and the Al ₂ O ₃ content is converted to 20% by weight. For example, SiO ₂ —CaO—MgO—20% Al ₂ O ₃ 4 shown in FIG. It is possible to derive using the original system phase diagram.

In the third step S3, the metal species supported on the coal is the data obtained in the first step S1 (Al, Si, Ca, Mg oxide in ash content is 100% by weight, Al ₂ O ₃ When selecting the content based on 20% by weight of SiO ₂ wt%, CaO wt%, MgO wt%) and the data obtained in the second step S2 (the ash melting point of coal) preferable.
As the metal type (metal type), it is preferable to select at least one of alkaline earth metals such as magnesium (Mg) and calcium (Ca). In particular, when the ash content of the coal is large (SiO ₂ wt%, for example, 75 wt% or more) and the ash has a high melting point (for example, 1500 ° C. or more), the coal contains It is preferable to carry calcium (Ca).

In the third step S3, the amount of the metal supported on the coal is the data obtained in the first step (Al, Si, Ca, Mg oxide in ash is 100% by weight, Al ₂ Derived based on SiO ₂ wt%, CaO wt%, MgO wt%, ash melting point of coal when the O ₃ content is converted to 20 wt%, and the metal selected in the third step S3 It is preferable to do.

In the fourth step S4, the metal-supporting coal is, for example, the coal in an alkali aqueous solution of the metal (for example, Ca (OH) ₂ or Mg (OH) ₂ ) for a certain time (for example, 1 hour to 8 hours) soaking and dehydrating.

  In the fifth step S5, the metal-supported coal is preferably heat-treated at 350 to 550 ° C., for example, for 30 minutes to 2 hours in a heat treatment furnace such as a kiln so that the residual volatile content is 15 to 35%. . As a result, the metal is nanoparticulated (several tens to several hundreds of nanometers) and is evenly dispersed in the obtained blast furnace-blown coal.

The blast furnace injection coal manufactured by the method for preparing the blast furnace injection coal according to this embodiment has Al, Si, Ca, Mg oxide in the ash content of coal as 100% by weight, and Al _{2 in the} ash content. The metal is supported on the coal by an ion exchange method so that the ash melting point of the coal is less than 1400 ° C. when the O ₃ content is 20% by weight, and the coal supporting the metal is dry-distilled. From the above, the metal supported on the coal is nanoparticulated and dispersed evenly in the coal, accelerating the mixing and homogenization of the combustion ash, the nanoparticulated metal and the slag in the blast furnace body. Even if the blowing amount of the blast furnace is increased, it is possible to obtain blast furnace blowing charcoal in which poor flow of the slag in the blast furnace body hardly occurs. Thereby, the amount of coke used can be reduced.

Further, the metal in the form of nanoparticles has a catalytic action, and can promote the combustion / gasification reaction even at a low temperature in the presence of oxygen.
The coal ash and the metal are dispersed in the coal, and the mixing of the nanoparticulated metal with the combustion ash and slag starts after the coal burns, before being blown into the tuyere of the blast furnace body In addition, by making the metal into nanoparticles, the combustion starts and ends quickly, and the start of mixing becomes faster, so that the homogenization speed becomes faster.
By dry-distilling the coal before blowing into the tuyere of the blast furnace body, no heat of pyrolysis is required, and the amount of inert pyrolysis gas is reduced, resulting in a high combustion temperature and a high combustion rate. As a result, the combustion ends quickly and the start of mixing becomes faster.
That is, by carbonizing the coal before blowing into the tuyere of the blast furnace main body, the combustion is accelerated by the change in the properties of the coal and the nanoparticulation of the metal, and the nanoparticulate metal, combustion coal, and slag Mixing is carried out at an early stage, and the mixing and homogenization thereof is accelerated, so that the fluidity of the mixing slag is increased and the discharge performance is improved.

  In Patent Document 2, since flux is blown, it is necessary to provide a storage tank and a blow nozzle for the flux for each blast furnace, and the apparatus becomes complicated depending on the number of blast furnaces. Since the desired blast furnace-blown coal can be obtained, the apparatus is not complicated and the operation reliability of the blast furnace can be improved.

In the case of carrying calcium into the coal, Al in the ash of the coal, Si, Ca, the total weight is 100 wt% Al ₂ O ₃ content of Mg oxide when converted to 20 wt%, The total weight percent of calcium oxide (CaO) and magnesium oxide (MgO) is 0.2 (= 0.14 / 0.66) or more and 1.55 (= 0.486) based on the weight percent of silica (SiO ₂ ). /0.314) or less, more preferably 0.25 (= 0.16 / 0.64) or more and 1.4 (= 0.47 / 0.33) or less, and 0.35 (= More preferably, it is 0.208 / 0.592) or more and 1 (= 0.4 / 0.4) or less. That is, calcium oxide is preferably supported on the coal so that the total weight percent of calcium oxide (CaO) and magnesium oxide (MgO) is 14% to 48% by weight, and calcium oxide (CaO) and magnesium oxide ( More preferably, the calcium oxide is supported on the coal so that the total weight% of MgO) is 16 wt% to 47 wt%, and the total weight% of calcium oxide (CaO) and magnesium oxide (MgO) is 21 wt%. It is even more preferable to support calcium oxide on the coal so as to be ˜40% by weight. This is because various coals whose ash content and ash melting point are already known are summarized by focusing on the weight ratio of calcium oxide and magnesium oxide to silica and the ash melting point, as shown by the black circles shown in FIG. This is because the approximate line of data becomes a curve L1 shown in FIG. That is, as shown in FIG. 3, when (CaO + MgO) / SiO ₂ is smaller than 0.2 or larger than 1.55, the ash melting point of the blast furnace blowing coal becomes higher than 1400 ° C., which is not preferable. When (CaO + MgO) / SiO ₂ is smaller than 0.25 or larger than 1.4, the ash melting point of the blast furnace blown coal becomes higher than 1300 ° C., and (CaO + MgO) / SiO ₂ is not preferable. This is because if it is smaller than 0.35 or larger than 1, the ash melting point of the blast furnace-blown coal becomes higher than 1200 ° C., which is not preferable.

[Other Embodiments]
In the above description, the method for preparing blast furnace blown coal in which alkaline earth metals such as Mg and Ca are supported on the coal by the ion exchange method has been described. However, alkaline metal such as beryllium (Be) is used as the metal. It is also possible to use a method for preparing blast furnace-blown coal supported on the steel. Even such a method for preparing blast furnace blown coal has the same effects as the method for preparing blast furnace blown coal according to the above-described embodiment.

  Moreover, it is also possible to set it as the preparation method of blast furnace injection coal which carry | supports boron group elements, such as aluminum (Al), to coal. Even such a method for preparing blast furnace blown coal has the same effects as the method for preparing blast furnace blown coal according to the above-described embodiment.

  It is also possible to use a method for preparing blast furnace blown coal in which an alkali metal such as Li, Na, K or the like is supported on the coal. Even such a method for preparing blast furnace blown coal has the same effects as the method for preparing blast furnace blown coal according to the above-described embodiment.

  Examples carried out to confirm the operational effects of the method for preparing blast furnace blow coal according to the present invention will be described below, but the present invention is limited only to the following examples described based on various data. It is not a thing.

  First, as shown in FIG. 1, while analyzing the moisture content and raw coal ash of coal type A, the weight percentage of Al, Si, Ca, Mg in the ash of the coal is analyzed in advance. (First step S1).

When the total weight of Al, Si, Ca, Mg oxide in the ash content of the coal type A is 100% by weight and the Al ₂ O ₃ content is converted to 20% by weight, the coal type A The content of each oxide of Si, Ca, and Mg in the ash content of A indicates the value shown in Table 1 above. Therefore, the ash melting point of the coal type A is SiO ₂ —CaO— when Al, Si, Ca, Mg oxide in the ash content of coal is 100 wt% and the Al ₂ O ₃ content is converted to 20 wt%. In FIG. 2, which is a quaternary phase diagram of MgO-20% Al ₂ O ₃ , it is positioned as coal type A.

Subsequently, the CaO content in the ash when the total weight of Al, Si, Ca, Mg oxide in the ash of the coal type A is 100% by weight and the Al ₂ O ₃ content is converted to 20% by weight. Based on the MgO content and the SiO ₂ content, for example, the ash melting point of the coal type A is obtained using FIG.

  Subsequently, from the region where the ash melting point of the coal type A and the ash melting point of the coal are less than 1400, the metal type supported on the coal type A is selected and the loading amount of the selected metal on the coal type A is derived. To do. Here, it can be seen that by supporting about 10% by weight of CaO on the coal type A, the ash melting point of the coal becomes 1400 ° C. or lower, so CaO is selected as the metal type supported on the coal type A, 10% by weight is derived as the loading amount.

  Subsequently, the blast furnace blown coal with an ash melting point of 1400 ° C. or less can be obtained by carrying the CaO on the coal type A by ion exchange and dry distillation.

  Therefore, according to this example, the ash content of coal at the time of raw coal is analyzed, and the weight percent of Al, Si, Ca, Mg in the ash content of coal is analyzed, and the data obtained by analysis is obtained. Based on the obtained data, the ash melting point of the coal is derived, and based on the obtained data, the CaO (metal species) supported on the coal is selected so that the melting point of the coal ash is 1200 to 1400 ° C. Deriving the loading amount, loading the supported amount of the metal on the coal by ion exchange method, and by dry distillation, the metal supported on the coal is nanoparticulate and uniformly dispersed in the coal, and the combustion ash and Blast furnace injection is less likely to cause poor flow of slag in the blast furnace body, even if the amount of injection into the blast furnace body is increased, because the mixing and homogenization of the slag in the blast furnace body is accelerated. To get charcoal It became clear that you can.

  According to the present invention, even if the amount of injection into the blast furnace body is increased, it is possible to obtain blast furnace injection charcoal that is unlikely to cause poor flow of slag in the blast furnace body. be able to.

Approximate line obtained from L1 data (line showing the relationship between (CaO + MgO) / SiO ₂ and ash melting point of blast furnace-blown coal)
S1 1st process (analysis process)
S2 Second step (Deriving step of coal ash melting point)
S3 Third step (supported metal species selection and supported amount derivation step)
S4 Fourth step (supporting step)
S5 5th process (dry distillation process)

Claims (8)

A method for preparing blast furnace-blown coal that is blown into a blast furnace body of a blast furnace facility from a tuyere,
A first step of analyzing coal ash at the time of coal raw coal and weight% of Al, Si, Ca, Mg in the ash;
A second step of deriving the ash melting point of the coal based on the data obtained by analysis;
Based on the data obtained in the first step and the second step, the metal species to be supported on the coal is selected so that the melting point of the ash of the coal is 1200 to 1400 ° C., and the supported amount A third step of deriving
A fourth step of supporting the amount of the metal on the coal by an ion exchange method;
And a fifth step of dry distillation of the coal obtained in the fourth step. A method for preparing blast furnace blown coal according to claim 1,
The said metal is at least 1 sort (s) of calcium or magnesium, The preparation method of blast furnace injection charcoal characterized by the above-mentioned. A method for preparing blast furnace-blown coal according to claim 1 or claim 2,
In the fifth step, the coal is heat-treated at 350 to 550 ° C to have a residual volatile content of 15 to 35%. A method for preparing blast furnace-blown coal according to any one of claims 1 to 3,
The amount of the metal supported on the coal is 0.2 to 1.55 in a weight ratio of (CaO + MgO) / SiO ₂ . A method for preparing blast furnace blown coal according to claim 4,
The amount of the metal supported on the coal is 0.25 to 1.4 in a weight ratio of (CaO + MgO) / SiO ₂ . A method for preparing blast furnace blown coal according to claim 5,
The amount of the metal supported on the coal is 0.35 to 1 in a weight ratio of (CaO + MgO) / SiO ₂ . A blast furnace blown coal obtained by the method for preparing a blast furnace blown coal according to any one of claims 1 to 6. A blast furnace in which blast furnace blown coal obtained by the method for preparing blast furnace blown coal according to any one of claims 1 to 6 is blown into a blast furnace body of a blast furnace facility from a tuyere. How to use blow charcoal.

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