JP2009013222A - Method of manufacturing modified coal and manufacturing method of coke - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of reforming low-grade coal containing a large amount of oxygen atoms without generating a large amount of water, and to provide a method of manufacturing coke for iron-making by using the same. <P>SOLUTION: A method of manufacturing modified coal by treating low-grade coal with heavy oils comprises: a catalyst-carrying step of causing low-grade coal containing a large amount of oxygen atoms to carry a metal and/or a metal compound; a porosification step of drying the low-grade coal carrying the catalyst and subsequently porosifying the low-grade coal by heating it at a temperature of 300-1,200°C in an inert atmosphere or in a slightly oxidizing atmosphere; and a modifying step of heating the porous low-grade coal after the porosification step together with heavy oils at a temperature of 300-500°C in an inert atmosphere or in a reducing atmosphere, thereby causing decomposate of heavy oils to adhere to the surface of the porous low-grade coal. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention modifies low-grade coal containing a large amount of oxygen atoms and is suitable for the production of coke for iron making, that is, a method for producing artificial caking coal, and the reformed coal of the blended coal. The present invention relates to a method for producing coke using as a raw material.

  Iron coke used in steelworks blast furnaces is a blended coal by mixing (compounding) dozens of brands including caking coal belonging to bituminous coal, and the blended coal is heated to 1000-1400 ° C in the coke oven. It is manufactured by heating around 20 hours and performing high temperature carbonization. In recent years, the caking coal necessary for producing iron-making coke is actually lacking, and from this, the use of low-grade coal has been studied. Low-grade coal is a coal with a ratio of aromatic carbon to total carbon of 50-60%, and there are many reserves and many coal types with low ash and sulfur content, but there is a lot of moisture and a calorific value. There is a problem that it is low, has a high oxygen content, and is not dense, so that it is easily pulverized and easily ignites.

Therefore, low-grade coals such as subbituminous coal, lignite, lignite, and peat are reformed at 400 to 450 ° C. using a solvent in a hydrogen atmosphere as shown in Patent Document 1 and Patent Document 2, and are graded. And a technique for utilizing this for coke production is disclosed. In Patent Document 3, a mixture of low-grade coal and heavy hydrocarbon is heat-treated at 300 to 500 ° C., and distilled under conditions of a tower bottom temperature of 250 to 320 ° C. and a pressure of 40 mmHg or less. Techniques for obtaining charcoal and tar oil are disclosed. Furthermore, Patent Document 4 discloses a technique for obtaining a reformed coal and a light oil fraction by liquid phase decomposition of low-grade coal at 400 to 450 ° C.
JP 53-104603 A Japanese Patent Laid-Open No. 55-69691 JP 58-217593 A Japanese Patent No. 3198306

  However, since Patent Document 1 and Patent Document 2 use a method of reforming low-grade coal by heat treatment in a hydrogen atmosphere, oxygen atoms contained in a large amount in hydrogen and low-grade coal ( About 27% by mass) to form a large amount of water. For this reason, these technologies are low in the amount of reformed coal acquired and inefficient, and are equipped with an oil / water separator for removing a large amount of generated water, and an advanced level for removing oil mixed in moisture. In addition to having to install a large wastewater treatment facility, a large amount of hydrogen gas is required, so it is necessary to increase the size of the gas compression / circulation facility.

  Further, in Patent Document 3 and Patent Document 4, oxygen atoms of low-grade coal react with hydrogen atoms in the solvent (heavy oil), or oxygen atoms and hydrogen atoms contained in the low-grade coal react. Since a large amount of water is generated, the product can be obtained in a mixed state of reformed coal, solvent (heavy oil) and water. There was a problem of becoming larger.

  Therefore, the present invention was developed in view of the above problems, a method for reforming low-grade coal containing a large amount of oxygen atoms without generating a large amount of water, and for iron making using the same It aims at providing the manufacturing method of coke.

  As a result of intensive studies to achieve the above object of the present invention, the present invention provides a method for producing modified coal by treating low-grade coal with heavy oils. And a catalyst supporting step for supporting a metal and / or a metal compound, and drying the low-grade coal after supporting the catalyst, followed by heating to a temperature of 300 to 1200 ° C. in an inert atmosphere or a slightly oxidizing atmosphere. The porous low-grade coal after the porous formation step and the porous low-grade coal after the porous formation step are heated to a temperature of 300 to 500 ° C. in an inert atmosphere or a reducing atmosphere together with heavy oils. And a reforming step of attaching a decomposition product of heavy oils to the surface of the high-grade coal.

In the present invention, the reforming step is performed in a hydrogen-containing atmosphere, the low-grade coal is lignite, the metal is iron, and the porous after the porosification step. The specific surface area of the low-grade coal is 300 to 1500 m ² / g, and the adhesion amount of the decomposition products to the surface of the porous low-grade coal is 3 to 5 times that of the low-grade coal. Being present can provide a more preferable solution.

  Moreover, this invention charges the coal blend containing the modified coal obtained by the manufacturing method of any one of Claims 1-6 in a coke oven, and heat-distills at 1000-1200 degreeC. We propose a coke production method characterized by

In the present invention having the above-described configuration, the low-grade coal as the raw coal is deoxidized before the reforming so that the oxygen content is 15% by mass or less. Does not generate a large amount of water during the quality treatment process. As a result, low-grade coal can be reformed efficiently, and equipment such as oil-water separators and wastewater treatment facilities can be omitted. Charcoal and steelmaking coke can be obtained.
In addition, since the low-grade coal after deoxidation is porous, it can adhere and retain a large amount of heavy components in the pores, and also has high adhesion, thus improving the coke strength. be able to.

  The method for producing modified coal of the present invention mainly comprises a catalyst supporting step for supporting a catalyst such as a metal and / or metal compound on low-grade coal, and heating the low-grade coal supporting the catalyst to make it porous. A porous process and a reforming process in which the porous low-grade coal after the porous process is heated together with heavy oil and a decomposition product of the heavy oil is attached to the surface of the low-grade coal. It is characterized by.

  In the present invention, the raw coal to be reformed is a low-grade coal having a high oxygen atom content such as subbituminous coal, lignite, lignite, and peat. As the brown coal, Australian-made Yarune coal, Moel coal, Royan coal and the like are suitable. In the present invention, biomass raw materials such as wood and coconut shells can be used in addition to or in place of the raw coal.

  In the present invention, first, a catalyst such as a metal and / or a metal compound is supported on the low-grade coal. This is because the action of the supported catalyst accelerates the decomposition of heavy oils and allows them to be efficiently converted into light fractions, as well as coke, carbon or their decomposition products of heavy products. This is because the heavy components such as the precursor are sufficiently adhered and held in the pores in the porous carbon material, and high quality modified coal can be obtained.

  That is, in the reforming step described later, heavy oils are broken by heating, and the hydrocarbon bonds having a relatively large molecular weight constituting the heavy oils are generated. This highly reactive hydrocarbon radical causes a chain reaction and bonds to each other, and finally causes a polycondensation reaction to become coke, carbon or a precursor thereof. In particular, in the decomposition of superheavy oil containing a large amount of asphaltenes, the tendency of the polycondensation reaction to proceed is increased.

  On the other hand, the catalyst has a function of promoting the addition of hydrogen to the hydrocarbon radical and stabilizing the hydrocarbon radical. In addition, porous charcoal has a property of slowly adsorbing hydrocarbon radicals. Therefore, the adsorbed hydrocarbon radicals are stabilized by adding hydrogen by the supported catalyst and desorbed from the porous coal, and heavy oils are efficiently converted into light fractions. It is.

  Note that the catalyst is supported on the surface of low-grade coal because low-grade coal often has pores from the beginning and water is held in the pores. It can be easily carried out by adding, and can be carried out by using a generally known impregnation method using an aqueous solution of a metal compound.

  Moreover, iron, cobalt, nickel or the like can be used as the catalyst metal, and iron is particularly preferable from the viewpoints of cost and ease of handling. Further, as the metal compound, nitrates such as iron, cobalt, nickel, hydrochlorides, sulfates, acetates, and the like can be used.

  The catalyst loading on the surface of the low-grade coal may be performed in an undried state or after being dried once, and is preferably performed in an undried state from the viewpoint of energy saving. .

  Next, a description will be given of a porosification step in which low-grade coal carrying a catalyst is dried and then heated to make it porous. First, as a drying method, as described above, low-grade coal is often in a state where water is retained in the pores, so it is preferable to carry out so as not to crush the pores. For example, supercritical drying or freeze drying is preferable. In normal hot air drying, when lignite with pores in the raw materials such as lignite, lignite, and peat is dried, the lignite contracts due to the capillary force of the water embedded in the pores, and the pore structure is destroyed. There is a risk that. In this regard, in the case of supercritical drying, since the gas-liquid interface does not appear during drying, moisture is removed while leaving the pore structure.

  Subsequently, the low-grade coal dried as described above is heat-treated. Since oxygen atoms in the low-grade coal are released mainly as carbon monoxide or carbon dioxide by heat treatment, the oxygen content of the low-grade coal becomes 15% by mass or less, and water in the subsequent reforming process Can be reduced. In addition, the part from which oxygen atoms in the low-grade coal are lost becomes pores and contributes to the porous formation. In addition, in order to activate the catalyst supported on the low-grade coal, after adding the carbonization by heating the low-grade coal, heating and reducing under a hydrogen atmosphere, etc. Also good.

The heat treatment of the low-grade coal is performed at 300 to 1200 ° C., preferably about 400 to 800 ° C. under an inert atmosphere such as nitrogen, argon, helium or the like, or a slightly oxidizing atmosphere containing CO ₂ . Depending on the temperature, it can be carried out using a fixed bed furnace, tunnel furnace, rotary furnace, fluidized bed furnace or the like.

  The reason for performing the heat treatment in an inert atmosphere or a slightly oxidizing atmosphere in the porosification process is that a porous structure is formed by the release of carbon monoxide and carbon dioxide in the drying and heat treatment, so that strong oxidation occurs. This is because when the heat treatment is performed in a neutral atmosphere, even the carbon corresponding to the walls forming the pores is oxidized (burned).

  In addition, the heating temperature is set in the range of 300 to 1200 ° C. When the heating temperature is 300 ° C. or less, the porous surface does not sufficiently become porous and the specific surface area is small. This is because, in addition to a decrease in size, the energy is wasted.

Incidentally, the porous low-grade coal after porous step has a specific surface area measured by the BET method using nitrogen gas 300~1500m ² / g, preferably about about 600~1200m ² / g porous coal It is preferable that This is because if the specific surface area is too small, the adhesion between the low-grade coal and the decomposition products of heavy oils becomes weak, and the strength when coke is produced using this is insufficient. On the other hand, when the specific surface area of the low-grade coal is too large, pores having small pore diameters that do not contain decomposition products increase, and the coke strength decreases.

Next, the reforming process will be described.
In the reforming process, the porous porous low-grade coal (hereinafter referred to as “porous coal”) is heated in heavy oil (petroleum heavy oil or coal heavy oil). , Very heavy components such as coke, carbon, or their precursors generated by pyrolysis of heavy oils enter and adsorb into the pores of the porous coal.

  In this reforming step, porous charcoal and heavy oil are heated to about 300 to 500 ° C. in an inert atmosphere or a reducing atmosphere, and particularly in a reducing atmosphere mainly composed of hydrogen gas. It is preferable to heat to 380-460 degreeC. This is because pyrolysis of heavy oils is a kind of disproportionation reaction, so that heavy components such as coke or carbon are produced, while light components are also produced, but when hydrogen gas is present, It is assumed that the viscosity of the light component is lowered, the movement of a very heavy component such as coke, carbon, or a precursor thereof is facilitated, and the penetration and adsorption into the pores are facilitated.

  This reforming step can be suitably performed by a complete mixing tank type such as a fixed bed, a moving bed, a suspension (slurry bed), a boiling bed, and the like, as well as a suspension bed and a boiling bed.

  The amount of the decomposition product (heavy content) attached to the porous coal is preferably 5 times (mass ratio) or less of the porous coal. This is because if the amount of decomposition products deposited becomes too large, the physical properties of oil coke will not change, and it will not be possible to use as raw coal.

  Here, petroleum heavy oil is heavy oil and super heavy oil related to petroleum refining, and heavy oil is, for example, crude oil, petroleum-based atmospheric distillation residue, vacuum distillation residue, contact Residual oil such as cracked residual oil or oil sand oil, oil shale oil, etc., and super heavy oil, for example, Maya from Mexico, Athabasca oil sand bitumen from Canada, Cold Lake oil sand bitumen, Venezuela It is a kind of oil such as Orinocotar, Celonegro, Zuata, Batchachero, Boscan, and Marim produced in Brazil. The coal-based heavy oil is a heavy fraction that is fractionated by distillation of coal tar generated from a coke oven, such as creosote oil, anthracene oil, and pitch. There is also a heavy fraction of liquefied oil obtained by liquefaction of coal.

  And in this invention, after attaching a decomposition product to porous charcoal as mentioned above, extra oil is separated using methods, such as usual filtration, centrifugation, and distillation, and reformed charcoal. And

  The reformed coal obtained in this way may be used as it is as raw coal for blended coal, but it is further improved by modifying the properties of the reformed coal by subjecting it to some modification or heat treatment. May be. In particular, when the decomposition product more than 5 times adheres to and adsorbs to the porous coal, this modification treatment or heat treatment is effective.

  The modification treatment is a method of heating to about 150 to 300 ° C. in the air, and a method of heating to a temperature of about 300 to 600 ° C. in an inert atmosphere or a reducing atmosphere. Moreover, when performing under reduced pressure, since a part of decomposition product volatilizes, what is necessary is just to heat at about 200-400 degreeC.

  Next, a method for producing coke using the modified coal obtained as described above will be described. The reformed coal that has undergone the above-mentioned treatment is subjected to particle size adjustment such as pulverization and granulation, if necessary, and is introduced into a blending tank of a coke oven in the same manner as other raw coals to adjust the blended coal. The blended charcoal is charged into a coke oven kiln with a charcoal car and dry-distilled at 1000 to 1200 ° C. for about 20 hours under a natural gas reducing atmosphere. Then, it extrudes from a kiln with an extruder, cools to normal temperature with a CDQ equipment, and is set as iron-making coke.

Example 1
a. Catalyst loading step: Brown coal having volatile content: 40-50% by mass, ash content: 0.5% by mass (component composition: carbon 67.1% by mass, hydrogen 4.3% by mass, nitrogen 0.9% by mass, sulfur 0. 2% by mass, 27.0% by mass oxygen) with water adhering (about 60% by mass to dry charcoal), immersed in an aqueous iron nitrate solution for 3 hours to carry 5% by mass of Fe, and then frozen. Dried.
b. Porous Step Next, it was placed in a SUS rotary kiln furnace having an inner diameter of 600 mm, heated from room temperature to 600 ° C. at a rate of 5 ° C./min under nitrogen gas flow, and maintained at 600 ° C. for 60 minutes to obtain porous coal Got. The properties of the obtained porous coal are shown in Table 2.
c. Next, 5 kg of porous charcoal and 20 kg of pitch are put into an induction-stirring autoclave with an internal volume of 50 liters and kept at 380 ° C. for 60 minutes in a nitrogen atmosphere (pressure: 0.98 MPa (10 Kg / cm ² G)). Thereafter, the reaction product was taken out from the autoclave, and heat treatment was performed at 430 ° C. for 30 minutes under a nitrogen gas flow to remove the light oil, thereby obtaining modified coal.
A blended coal was prepared by adding a base blended coal of caking coal prepared by mixing four modified (A to D coal) coals (coking coal for coke) shown in Table 1 to 10% by mass of this modified coal. . And this coal mix was dry-distilled in a 1100 degreeC coke oven for 18 to 20 hours, and coke was obtained. The filling density of the blended coal was 0.76 kg / liter. The drum strength (DI ³⁰ ₁₅ ) of the prepared coke was measured according to JIS K2151. The results are shown in Table 2.

(Example 2)
a. Catalyst loading step The same lignite as in Example 1 was immersed in an aqueous iron nitrate solution for 3 hours with moisture adhering (about 60% by mass to dry coal), and 5% by mass of Fe was supported and then freeze-dried. .
b. Porous process This was placed in a SUS rotary kiln furnace having an inner diameter of 600 mm, heated to 400 ° C. under nitrogen gas flow, heated at that temperature for 60 minutes, and further heated at 450 ° C. for 60 minutes in a hydrogen atmosphere. After the reduction, the mixture was heated in a mixed gas of hydrogen and hydrogen sulfide (1: 0.25) at 450 ° C. for 30 minutes to perform a sulfiding treatment to obtain porous charcoal. The properties of the obtained porous coal are shown in Table 2.
c. Next, 0.05 kg of this porous charcoal and 0.95 kg of vacuum residual oil were put into a small continuous high-pressure reactor, under a hydrogen gas atmosphere (pressure: 9.8 MPa (100 Kg / cm ² G) ) At 380 ° C. for 45 minutes. The reaction product was subjected to atmospheric distillation and vacuum distillation to remove oil having a boiling point of less than 538 ° C. to obtain modified coal.
The blended coal is prepared by adding the base blended coal of caking coal prepared by mixing the four coals (A to D coal) shown in Table 1 (coking coal for coke) to 10% by mass of this modified coal. It was measured coke drum strength ^(DI _{30 15)} in the same manner as in example 1. The results are shown in Table 2.

(Example 3)
a. Catalyst supporting step After the lignite as in Example 1 was vacuum dried, it was immersed in an aqueous iron nitrate solution for 3 hours to support 5% by mass of Fe.
b. Next, it was placed in a SUS rotary kiln furnace having an inner diameter of 600 mm, heated from room temperature to 600 ° C. at 5 ° C./min under a nitrogen gas flow, and held at 600 ° C. for 60 minutes. Then, it switched to the slightly oxidizing atmosphere of carbon dioxide 30 vol% and nitrogen 70 vol%, heated up to 1000 degreeC at 5 degree-C / min, and hold | maintained at 1000 degreeC for 5 hours, and obtained porous charcoal. Properties of the obtained porous coal are shown in Table 2.
c. Next, 5 kg of porous charcoal and 20 kg of pitch are put into an induction-stirring autoclave with an internal volume of 50 liters and kept at 380 ° C. for 60 minutes in a nitrogen atmosphere (pressure: 0.98 MPa (10 Kg / cm ² G)). Thereafter, the reaction product was taken out from the autoclave, and heat treatment was performed at 430 ° C. for 30 minutes under a nitrogen gas flow to remove the light oil, thereby obtaining modified coal.
A blended coal was prepared by adding a base blended coal of caking coal prepared by mixing four modified (A to D coal) coals (coking coal for coke) shown in Table 1 to 10% by mass of this modified coal. . And this coal mix was dry-distilled in a 1100 degreeC coke oven for 18 to 20 hours, and coke was obtained. The filling density of the blended coal was 0.76 kg / liter. The drum strength (DI ³⁰ ₁₅ ) of the prepared coke was measured according to JIS K2151. The results are shown in Table 2.

(Comparative Example 1)
Brown coal (dried product) was mixed with base blended coal having the composition shown in Table 1, and carbonized in a coke oven at 1100 ° C. for 18 to 20 hours to obtain coke. The drum strength (DI ³⁰ ₁₅ ) of the obtained coke was measured according to JIS K2151, and the results are shown in Table 2.

(Comparative Example 2)
The base blended charcoal composed of the blend shown in Table 1 was filled so that the packing density was 0.76 kg / liter, and was subjected to dry distillation in a coke oven at 1100 ° C. for 18 to 20 hours to obtain coke. The drum strength (DI ³⁰ ₁₅ ) of the obtained coke was measured according to JIS K2151, and the results are shown in Table 2.

(Comparative Example 3)
After vacuum drying the same lignite as in Example 1, 5 kg of this lignite and 20 kg of pitch were put into an induction stirring autoclave having an internal volume of 50 liters, and under a nitrogen atmosphere (pressure: 0.98 MPa (10 Kg / cm ² G). It was kept at 380 ° C. for 60 minutes, after which the reaction product was taken out from the autoclave and heat treated at 430 ° C. for 30 minutes under a nitrogen gas flow to remove light oil and obtain modified coal.
A blended coal was prepared by adding a base blended coal of caking coal prepared by mixing four modified (A to D coal) coals (coking coal for coke) shown in Table 1 to 10% by mass of this modified coal. . And this coal mix was dry-distilled in a 1100 degreeC coke oven for 18 to 20 hours, and coke was obtained. The filling density of the blended coal was 0.76 kg / liter. The drum strength (DI ³⁰ ₁₅ ) of the prepared coke was measured according to JIS K2151. The results are shown in Table 2.

(Comparative Example 4)
After vacuum drying the same lignite as in Example 1, this was placed in a SUS rotary kiln furnace with an inner diameter of 600 mm, heated to 400 ° C. under nitrogen gas flow, heated at that temperature for 60 minutes, and further hydrogenated After reducing at 450 ° C. for 60 minutes in an atmosphere, the sulfurating treatment was performed by heating at 450 ° C. for 30 minutes in a mixed gas of hydrogen and hydrogen sulfide (1: 0.25). Subsequently, the sulfurized lignite is placed in a SUS rotary kiln furnace having an inner diameter of 600 mm, heated from room temperature to 600 ° C. at a rate of 5 ° C./min under a nitrogen gas flow, and held at 600 ° C. for 60 minutes. Porous charcoal was obtained.
Next, 5 kg of porous charcoal and 20 kg of pitch were put into an induction stirring autoclave having an internal volume of 50 liters, and maintained at 380 ° C. for 60 minutes under a nitrogen atmosphere (pressure: 0.98 MPa (10 Kg / cm ² G). Then, the reaction product was taken out from the autoclave, and heat treatment was performed at 430 ° C. for 30 minutes under a nitrogen gas flow to remove light oil, thereby obtaining modified coal.
A blended coal was prepared by adding a base blended coal of caking coal prepared by mixing four modified (A to D coal) coals (coking coal for coke) shown in Table 1 to 10% by mass of this modified coal. . And this coal mix was dry-distilled in a 1100 degreeC coke oven for 18 to 20 hours, and coke was obtained. The filling density of the blended coal was 0.76 kg / liter. The drum strength (DI ³⁰ ₁₅ ) of the prepared coke was measured according to JIS K2151. The results are shown in Table 2.

(Comparative Example 5)
The same lignite as in Example 1 was immersed in an iron nitrate aqueous solution for 3 hours while adhering moisture (about 60% by mass to dry coal), and 5% by mass of Fe was supported, followed by vacuum drying.
Subsequently, 5 kg of this lignite and 20 kg of pitch were put into an induction-stirring autoclave having an internal volume of 50 liters, and maintained at 380 ° C. for 60 minutes in a nitrogen atmosphere (pressure: 0.98 MPa (10 Kg / cm ² G). The reaction product was taken out from the autoclave and heat-treated at 430 ° C. for 30 minutes under a nitrogen gas flow to remove light oil to obtain modified coal.
A blended coal was prepared by adding a base blended coal of caking coal prepared by mixing four modified (A to D coal) coals (coking coal for coke) shown in Table 1 to 10% by mass of this modified coal. . And this coal mix was dry-distilled in a 1100 degreeC coke oven for 18 to 20 hours, and coke was obtained. The filling density of the blended coal was 0.76 kg / liter. The drum strength (DI ³⁰ ₁₅ ) of the prepared coke was measured according to JIS K2151. The results are shown in Table 2.

(Comparative Example 6)
The same lignite as in Example 1 was immersed in an iron nitrate aqueous solution for 3 hours with moisture attached (about 60% by mass to dry coal), and 5% by mass of Fe was supported, followed by freeze-drying.
Subsequently, it was placed in a SUS rotary kiln furnace having an inner diameter of 600 mm, heated from room temperature to 250 ° C. at a rate of 5 ° C./min under a nitrogen gas flow, and held at 250 ° C. for 60 minutes for firing. The properties of the obtained fired product are shown in Table 2.
Next, 5 kg of the fired product and 20 kg of pitch were put into an induction stirring autoclave having an internal volume of 50 liters, and kept at 380 ° C. for 60 minutes under a nitrogen atmosphere (pressure: 0.98 MPa (10 Kg / cm ² G). The reaction product was taken out from the autoclave and heat-treated at 430 ° C. for 30 minutes under a nitrogen gas flow to remove light oil to obtain modified coal.
A blended coal was prepared by adding a base blended coal of caking coal prepared by mixing four modified (A to D coal) coals (coking coal for coke) shown in Table 1 to 10% by mass of this modified coal. . And this coal mix was dry-distilled in a 1100 degreeC coke oven for 18 to 20 hours, and coke was obtained. The filling density of the blended coal was 0.76 kg / liter. The drum strength (DI ³⁰ ₁₅ ) of the prepared coke was measured according to JIS K2151. The results are shown in Table 2.

(Comparative Example 7)
The same lignite as in Example 1 was immersed in an iron nitrate aqueous solution for 3 hours with moisture attached (about 60% by mass to dry coal), and 5% by mass of Fe was supported, followed by lyophilization.
Subsequently, it was placed in a SUS rotary kiln furnace having an inner diameter of 600 mm, heated from room temperature to 1250 ° C. at 5 ° C./min under nitrogen gas flow, and held at 1250 ° C. for 60 minutes for firing. The properties of the fired product obtained are shown in Table 2.
Next, 5 kg of the fired product and 20 kg of pitch were put into an induction stirring autoclave having an internal volume of 50 liters, and maintained at 380 ° C. for 60 minutes in a nitrogen atmosphere (pressure: 0.98 MPa (10 Kg / cm ² G). The reaction product was taken out from the autoclave and heat-treated at 430 ° C. for 30 minutes under a nitrogen gas flow to remove light oil to obtain modified coal.
A blended coal was prepared by adding a base blended coal of caking coal prepared by mixing four modified (A to D coal) coals (coking coal for coke) shown in Table 1 to 10% by mass of this modified coal. . And this coal mix was dry-distilled in a 1100 degreeC coke oven for 18 to 20 hours, and coke was obtained. The filling density of the blended coal was 0.76 kg / liter. The drum strength (DI ³⁰ ₁₅ ) of the prepared coke was measured according to JIS K2151. The results are shown in Table 2.

(Comparative Example 8)
The same lignite as in Example 1 was immersed in an iron nitrate aqueous solution for 3 hours with moisture attached (about 60% by mass to dry coal), and 5% by mass of Fe was supported, followed by freeze-drying.
Subsequently, it was placed in a SUS rotary kiln furnace having an inner diameter of 600 mm, heated from room temperature to 600 ° C. at 5 ° C./min under a nitrogen gas flow, and held at 600 ° C. for 60 minutes for firing. The properties of the fired product obtained are shown in Table 2.
Next, 5 kg of the fired product and 20 kg of pitch were put into an induction stirring autoclave having an internal volume of 50 liters, and kept at 280 ° C. for 60 minutes in a nitrogen atmosphere (pressure: 0.98 MPa (10 Kg / cm ² G). The reaction product was taken out from the autoclave and heat-treated at 430 ° C. for 30 minutes under a nitrogen gas flow to remove light oil to obtain modified coal.
A blended coal was prepared by adding a base blended coal of caking coal prepared by mixing four modified (A to D coal) coals (coking coal for coke) shown in Table 1 to 10% by mass of this modified coal. . And this coal mix was dry-distilled in a 1100 degreeC coke oven for 18 to 20 hours, and coke was obtained. The filling density of the blended coal was 0.76 kg / liter. The drum strength (DI ³⁰ ₁₅ ) of the prepared coke was measured according to JIS K2151. The results are shown in Table 2.

(Comparative Example 9)
The same lignite as in Example 1 was immersed in an iron nitrate aqueous solution for 3 hours with moisture attached (about 60% by mass to dry coal), and 5% by mass of Fe was supported, followed by freeze-drying.
Subsequently, it was placed in a SUS rotary kiln furnace having an inner diameter of 600 mm, heated from room temperature to 600 ° C. at 5 ° C./min under a nitrogen gas flow, and held at 600 ° C. for 60 minutes for firing. The properties of the fired product obtained are shown in Table 2.
Next, 5 kg of the fired product and 20 kg of pitch were put into an induction stirring autoclave having an internal volume of 50 liters, and kept at 550 ° C. for 60 minutes in a nitrogen atmosphere (pressure: 0.98 MPa (10 Kg / cm ² G). The reaction product was taken out from the autoclave and heat-treated at 430 ° C. for 30 minutes under a nitrogen gas flow to remove light oil to obtain modified coal.
A blended coal was prepared by adding a base blended coal of caking coal prepared by mixing four modified (A to D coal) coals (coking coal for coke) shown in Table 1 to 10% by mass of this modified coal. . And this coal mix was dry-distilled in a 1100 degreeC coke oven for 18 to 20 hours, and coke was obtained. The filling density of the blended coal was 0.76 kg / liter. The drum strength (DI ³⁰ ₁₅ ) of the prepared coke was measured according to JIS K2151. The results are shown in Table 2.

From the results of Table 2, in all of Examples 1 to 3, the oxygen content in the porous coal was 5% by mass, and the amount of water generated during the reforming process was slight. Moreover, the specific surface area of the brown coal after the heat treatment is in the range of 300 to 520 m ² / g, and the decomposition products of heavy oils adhere to it with a sufficient specific surface area. Could be manufactured.
On the other hand, in Comparative Examples 1 and 2, since the metal loading and porosification steps were not performed, a large amount of oxygen remained in the lignite, and thus a large amount of coke was generated. In Comparative Examples 3, 5 and 6, since the oxygen content in the porous coal is high (27% by mass), water is generated during the reforming process, and the specific surface area is also small, so that heavy oils are decomposed. The product could not be deposited sufficiently and the strength of the coke was lowered. In Comparative Examples 4 and 7, since the specific surface area is small, the decomposition product (heavy content) of heavy oils could not be sufficiently adhered in the reforming process, and the strength of coke was lowered. . In Comparative Examples 8 and 9, high drum strength could not be obtained.

  The present invention can be used in fields such as thermal power generation, petroleum refining, and chemical industry in addition to use as raw material coal for steel.

Claims (7)

In a method for producing modified coal by treating low-grade coal with heavy oils, a catalyst loading step for loading a metal and / or a metal compound on low-grade coal containing a large amount of oxygen atoms,
After the catalyst-supported low-grade coal is dried, it is made porous by heating to a temperature of 300 to 1200 ° C. in an inert atmosphere or a slightly oxidizing atmosphere, and
The porous low-grade coal after the porosification step is heated together with heavy oils to a temperature of 300 to 500 ° C. in an inert atmosphere or a reducing atmosphere, and heavy oils are applied to the surface of the porous low-grade coal. A reforming step for attaching a decomposition product of
A method for producing modified coal, characterized in that   The method for producing reformed coal according to claim 1, wherein the reforming step is performed in a hydrogen-containing atmosphere.   The method for producing reformed coal according to claim 1 or 2, wherein the low-grade coal is lignite.   The said metal is iron, The manufacturing method of the modified coal of any one of Claims 1-3 characterized by the above-mentioned. Method for producing a modified coal according to any one of claims 1 to 4, specific surface area of the porous low-grade coal after porous step is characterized by a 300~1500m 2 / ^g.   The adhesion amount of the decomposition product to the surface of the porous low-grade coal is 3 to 5 times that of the low-grade coal in terms of mass ratio. Method for producing modified coal.   A coke containing modified coal obtained by the production method according to any one of claims 1 to 6 is charged into a coke oven, and heated and dry distilled at 1000 to 1200 ° C. Production method.