A high-reactivity and high-strength heterogeneous coke for hydrogen-rich blast furnace and preparation method thereof

Abstract

The present invention relates to the field of high-reactivity and high-strength coke preparation, and in particular to a high-reactivity and high-strength heterogeneous coke for hydrogen-rich blast furnaces and a preparation method thereof. The preparation method comprises mixing formed coal with coking blend coal and then coking the coke. The preparation method of the present invention is simple to operate, has lower cost, and is suitable for large-scale production. The prepared high-reactivity and high-strength heterogeneous coke for hydrogen-rich blast furnaces comprises high-strength coke obtained by carbonizing formed coal and high-reactivity coke obtained by carbonizing loose coal materials of coking blend coal. The surfaces of the two are mutually infiltrated and fused together through the colloids formed during the coking process, so that the comprehensive reactivity and post-reaction strength of the coke are improved compared with conventional coke, which can make the hydrogen-rich blast furnace run smoothly, improve the utilization rate of coal gas, and achieve the purpose of carbon reduction.

Description

Technical Field

[0001] The present invention relates to the field of high-reactivity and high-strength coke preparation, and in particular to high-reactivity and high-strength heterogeneous coke for hydrogen-rich blast furnaces and a preparation method thereof. Background Art

[0002] Since traditional blast furnaces have high carbon emissions, in order to achieve the goal of carbon reduction, an operating method for hydrogen-rich blast furnaces has been proposed, using hydrogen as a reducing agent to replace part of the coke in the blast furnace to achieve the purpose of reducing carbon emissions. When hydrogen is used as a reducing agent in a blast furnace, the coke ratio will be lower than that of a traditional blast furnace, but the coke also has to play the role of a material column skeleton to ensure that the reducing gas can flow smoothly. In addition, hydrogen participates in the reduction reaction, which increases the amount of heat absorbed and reduces the temperature in the furnace. The rate at which the coke gasification reaction produces CO decreases as the temperature decreases. Therefore, the injection of coke oven gas must increase the reactivity of the coke. Therefore, the research on high-strength and high-reactivity coke plays an important supporting role in the research on hydrogen reduction ironmaking technology. Compared with ordinary coke, highly reactive coke has higher thermal reactivity and its strength can meet the production of hydrogen-rich blast furnaces. It has the characteristics of low initial reaction temperature and fast reaction rate.

[0003] A lot of research has been done on the preparation of high-reactivity and high-strength coke at home and abroad. Japan's research and production of high-strength and high-reactivity coke is generally achieved by adding catalysts, such as calcium-based, magnesium-based and iron-based catalysts. The high strength is generally adjusted by adding strong binders HPC.

[0004] Chinese patent CN113563913A uses long flame coal and dry distilled long flame coal and bituminous coal as raw materials, coal tar as binder, and then die-casts them into blocks. After dry distillation, high-reactivity and high-strength coke is obtained. This method can reduce production costs by adding long flame coal, but the molding pressure is high and industrialization is difficult to achieve.

[0005] Chinese patent CN1264952C prepares high-reactivity and high-strength coke by adjusting the proportion of coking coal with different adhesiveness and reflectivity in the blended coal. Although the reactivity is improved, the negative correlation between the reactivity of coke and the strength after the reaction is not changed.

[0006] Chinese patent CN102719264B prepares highly reactive coke by first preparing coal cores, then spraying asphalt, and finally bonding and mixing with loose coal. The quality of the coke is improved after the reaction compared with the traditional coke with the same raw material ratio, but the process is relatively complicated.

[0007] Chinese patent CN103468287B prepares highly reactive coke by combining iron ore powder with coking coal. However, while the reactivity of such coke is improved, its strength decreases significantly after the reaction. Summary of the invention

[0008] Existing technical means cannot solve the essence of the negative correlation between coke reactivity and post-reaction strength. Even if a solution is occasionally found, it cannot be achieved in large-scale production due to its complex process.

[0009] The technical problem to be solved by the present invention is: to provide a method for preparing high-reactivity and high-strength heterogeneous coke for hydrogen-rich blast furnaces, and to prepare high-reactivity and high-strength heterogeneous coke for hydrogen-rich blast furnaces by utilizing the existing mature coking process of matching coal.

[0010] In view of the shortcomings of the prior art, one of the objects of the present invention is to provide a method for preparing high-reactivity and high-strength heterogeneous coke for hydrogen-rich blast furnaces; a second object of the present invention is to provide high-reactivity and high-strength heterogeneous coke for hydrogen-rich blast furnaces prepared by the above preparation method.

[0011] The technical solution of the present invention:

[0012] The present invention provides a method for preparing highly reactive and high-strength heterogeneous coke for hydrogen-rich blast furnaces, which comprises mixing briquette coal with coking blend coal and then coking the briquette coal; wherein the briquette coal is prepared from raw materials including fat coal, coking coal and lean coal.

[0013] Preferably, by weight percentage, the fat coal is 35-45%, the coking coal is 35-50%, and the lean coal is 5-20%; preferably, the fat coal is 40-45%, the coking coal is 40-45%, and the lean coal is 10-15%;

[0014] Preferably, the raw material further comprises a binder, and preferably, the binder is 5-10%.

[0015] Preferably, the coking coal comprises two or more of long flame coal, gas coal, 1 / 3 coking coal, fat coal, coking coal and lean coal; preferably, in terms of weight percentage, the coking coal comprises 0-10% long flame coal, 5-35% gas coal, 5-50% 1 / 3 coking coal, 5-30% fat coal, 5-30% coking coal and 5-10% lean coal; more preferably, the coking coal comprises 5-10% long flame coal, 5-35% gas coal, 25-50% 1 / 3 coking coal, 5-15% fat coal, 10-20% coking coal and 5-10% lean coal.

[0016] Preferably, in terms of weight percentage, the molding coal is 30-50%, and the coking blend coal is 50-70%; preferably, the molding coal is 35-45%, and the coking blend coal is 55-65%.

[0017] Preferably, the apparent density of the coal molding on a dry basis is 1.0 to 1.2 t / m; preferably, the equivalent diameter of the coal molding is 10 mm to 50 mm; more preferably, the fineness of the coal molding is 75 to 88%.

[0018] Preferably, the binder is selected from one or more of water, coal tar and asphalt.

[0019] Preferably, the fineness of the coking blend coal is 66-88%; preferably, the moisture content of the coking blend coal is 10-12%.

[0020] Preferably, the coking blend coal further comprises a catalyst containing Ca and / or Fe; preferably, the content of the catalyst containing Ca and / or Fe is 0.1-1% based on the weight of the coking blend coal.

[0021] The present invention also provides a high-reactivity and high-strength heterogeneous coke for hydrogen-rich blast furnace prepared by the above preparation method.

[0022] Preferably, the coke reactivity CRI of the high-reactivity and high-strength heterogeneous coke for hydrogen-rich blast furnace is 30% to 45%, and the coke reaction strength CSR is 60% to 70%; preferably, the cold strength M of the high-reactivity and high-strength heterogeneous coke for hydrogen-rich blast furnace is 60% to 70%. 40 82% to 89%, cold strength M 10 It is 5% to 9%.

[0023] Beneficial effects of the present invention:

[0024] The invention adopts formed coal and controls the ratio of formed coal to blended coal to prepare a high-reactivity and high-strength heterogeneous coke for hydrogen-rich blast furnace. The heterogeneous coke is composed of high-strength coke obtained by carbonizing formed coal and high-reactivity coke obtained by carbonizing loose coal materials of coking blended coal. The colloid formed on the surfaces of the two materials during the coking process penetrates and fuses with each other. The high-strength coke formed by the formed coal part in the hydrogen-rich blast furnace is protected by the coke formed by the loose coal materials outside, and has higher strength after the reaction. The coke formed by the carbonization of the loose coal materials preferentially reacts with CO 2 The coke reacts with water vapor to improve the comprehensive reactivity and reactivity of the coke compared with conventional coke, which can make the hydrogen-rich blast furnace run smoothly, improve the utilization rate of coal gas, and achieve the purpose of carbon reduction. At the same time, the preparation method of the invention is simple to operate, has lower cost, and is suitable for large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic flow diagram of a method for preparing highly reactive and high-strength heterogeneous coke for a hydrogen-rich blast furnace according to the present invention;

[0026] Figure 2 This is a schematic structural diagram of the highly reactive and high-strength heterogeneous coke for hydrogen-rich blast furnaces of the present invention;

[0027] The markings in the figure are as follows: 1-high-strength coke formed by briquette coal; 2-high-reactivity coke formed by coking mixed coal bulk materials. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical scheme and technical effect of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention is described clearly and completely. The embodiments described below are part of the embodiments of the present invention, not all of them. In combination with the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] In the present invention, "reactivity of coke" refers to the ability of coke to react with carbon dioxide, oxygen and water vapor. Since the reaction of coke with oxygen and water vapor has a similar law to the reaction of carbon dioxide, the present invention uses the reaction between coke and carbon dioxide to evaluate the reactivity of coke in accordance with GB / T 4000-2017 (Test method for coke reactivity and post-reaction strength), that is, a certain mass of coke sample is weighed, placed in a reactor, and reacted with carbon dioxide at 1100°C for 2 hours, and the coke reactivity (Coke Reactivity Index, abbreviated as CRI) is expressed as the percentage of coke mass loss.

[0030] In the present invention, "coke strength after reaction" refers to the ability of coke after reaction to resist fragmentation and wear under mechanical force and thermal stress. The present invention evaluates the coke strength after reaction according to the method in GB / T 4000-2017 (Test method for coke reactivity and strength after reaction), that is, the coke after reaction, after the type I drum test, is expressed as the percentage of the mass of coke with a particle size greater than 10 mm to the mass of the coke after reaction (Coke Strength After Reaction, abbreviated as CSR).

[0031] In the present invention, "cold strength" refers to the strength of coke at room temperature, cold strength M40 refers to the crushing strength of coke at room temperature, and cold strength M10 is the wear resistance of coke at room temperature. The present invention evaluates the cold strength according to the crushing strength (M40) and wear resistance (M10) in GB / T 2006-2008 (Determination method of mechanical strength of coke). M40 refers to the mass percentage of coke larger than 40 mm after the drum test to the mass percentage of coke entering the drum; M10 refers to the mass percentage of coke smaller than 10 mm after the drum test to the mass percentage of coke entering the drum.

[0032] In a specific embodiment of the present invention, the present invention provides a method for preparing high-reactivity and high-strength heterogeneous coke for hydrogen-rich blast furnaces, comprising mixing briquette coal with coking blend coal and then coking the briquette coal; wherein the briquette coal is prepared from raw materials including fat coal, coking coal and lean coal.

[0033] In terms of weight percentage, the fat coal is 35-45%, the coking coal is 35-50%, and the lean coal is 5-20%; preferably, the fat coal is 40-45%, the coking coal is 40-45%, and the lean coal is 10-15%.

[0034] The coking blend coal referred to in the present invention refers to a mixture of different single types of coal and additives added as needed in a certain proportion, for example, a mixture of two or more of long flame coal, gas coal, coking coal, fat coal, 1 / 3 coking coal and lean coal; further, the coking blend coal contains high-volatile weakly caking coal; the high-volatile weakly caking coal referred to in the present invention refers to coal types that can be used for coking except fat coal and coking coal, for example: the high-volatile weakly caking coal is selected from two or more of long flame coal, gas coal, 1 / 3 coking coal and lean coal; further, based on the weight of the coking blend coal, the coking blend coal contains 5-10% long flame coal, 5-35% gas coal, 25-50% 1 / 3 coking coal, 5-15% fat coal, 10-20% coking coal and 5-10% lean coal.

[0035] In the present invention, by weight percentage, the briquette coal is 30-50%, and the coking blend coal is 50-70%; preferably, the briquette coal is 35-45wt%, and the coking blend coal is 55-65%.

[0036] In the present invention, the coking blended coal further comprises a catalyst containing Ca and / or Fe; preferably, the content of the catalyst containing Ca and / or Fe is 0.1-1% based on the weight of the coking blended coal, which can improve the strength of the coke formed by the blended coal after the reaction.

[0037] In a preferred embodiment of the present invention, the above preparation method adopts a method of coking with profiled coal, comprising the following steps:

[0038] 1) Mix fat coal, coking coal, lean coal and binder and other raw materials evenly, and make briquette coal through a double-roller pelletizing machine. The apparent density of the briquette coal on a dry basis is 1.0t / m3~1.2t / m3, and the equivalent diameter is 10mm~50mm;

[0039] 2) The above-mentioned briquette coal and the coking coal bulk material are mixed evenly and then sent to the top-loading coke oven for coking;

[0040] 3) The mature coke is quenched to obtain hydrogen-rich heterogeneous coke for blast furnace.

[0041] The present invention also provides a high-reactivity and high-strength heterogeneous coke for a hydrogen-rich blast furnace prepared by the above preparation method.

[0042] The coke reactivity CRI of the above-mentioned high-reactivity and high-strength heterogeneous coke for hydrogen-rich blast furnace is 30% to 45%, and the coke post-reaction strength CSR is 60% to 70%; preferably, the cold strength M40 of the high-reactivity and high-strength heterogeneous coke for hydrogen-rich blast furnace is 82% to 89%, and the cold strength M10 is 5% to 9%.

[0043] The highly reactive and high-strength heterogeneous coke for hydrogen-rich blast furnace and the preparation method thereof are described in detail below through specific examples. In the examples, all raw reagent materials are commercially available, and the experimental methods without specific conditions are conventional methods and conventional conditions well known in the art, or according to the conditions recommended by the instrument manufacturer.

[0044] The specific names of the coking coal used are: Jiangchang gas coal, Dongshan 1 / 3 coking coal, Gengyang coking coal, Hongyang lean coal, Heishan long flame coal, Longhu fat coal. Each type of coal conforms to the definition of coking coal classification in the national standard GB / T 5751-2009.

[0045] The 40kg test coke oven (top-mounted) is homemade and complies with the current industry standard "Technical Specifications for Small Coke Ovens for Coking Tests".

[0046] The schematic flow diagram of the method for preparing coke in the embodiment is as follows Figure 1 As shown, Figure 1 The preparation method of the coke is to firstly make fat coal, coking coal and lean coal into shaped coal, then blend the coal, and obtain high-reactivity and high-strength heterogeneous coke for hydrogen-rich blast furnace through coking.

[0047] Example 1

[0048] 30kg of the mixture was mixed with 35wt% fat coal, 43wt% coking coal, 13wt% lean coal and 9wt% coal tar in a mixer, and then formed into briquette coal by a roller pelletizing machine. The apparent density of the briquette coal on a dry basis was 1.2t / m3, the equivalent diameter was 10mm, the fineness of the coal material was 80%, and the coal tar came from the residual ammonia water storage tank of the metallurgical coking plant.

[0049] 30kg of a mixture of 31wt% gas coal, 35wt% 1 / 3 coking coal, 8wt% fat coal, 11wt% coking coal, 5wt% lean coal and 10wt% long flame coal is prepared by a mixer. Then 18kg of molded coal and 22kg of the mixture of 30kg coking coal are weighed respectively. After mixing evenly, the mixture is sent into a 40kg top-loading coke oven for coking. The coking conditions are coal loading at 800°C on the furnace wall and the final coking temperature is 950°C at the center of the coke cake, which is maintained for 1 hour to obtain high-reactivity and high-strength heterogeneous coke for hydrogen-rich blast furnaces. The bulk density of the loose coal is 0.75, the fineness is 75%, and the moisture is 10%.

[0050] The coke reactivity and post-reaction strength experimental method of GB / T 4000-2017 was used to measure the coke reactivity CRI of the high-reactivity and high-strength heterogeneous coke for hydrogen-rich blast furnace prepared in Example 1 to be 38.5%, and the coke post-reaction strength CSR to be 65.3%.

[0051] The cold strength M40 of the high-reactivity and high-strength heterogeneous coke for hydrogen-rich blast furnace prepared in Example 1 was measured to be 85.3% and the cold strength M10 was 7.8% by using the test method of coke mechanical strength in GB / T 2006-2008. The specific method is as follows:

[0052] 1) The sample is manually screened with a 60mm diameter round hole sieve, and the holes are manually punched (i.e. the material on the sieve is manually tried to pass through the sieve holes, and as long as it can pass through the sieve holes in one direction, it is counted as the material under the sieve). During screening, the amount of material put into the sieve each time shall not exceed 15kg, and the sieve shall be screened cleanly, but the coke shall not be broken by excessive force. The material on the sieve (coke larger than 60mm) is weighed as the drum sample and placed in the container to be put into the drum. Each sample is 15kg (weighed to 0.1kg), and at least two samples should be taken for each test.

[0053] 2) Carefully place one of the test pieces into the cleaned drum, close the drum cover, remove the drum crank, start the drum, stop the drum after 100 revolutions, let it stand for 1-2 minutes to allow the dust to settle, then open the drum cover, pour out the coke in the drum, clean it carefully, and collect the coke powder on the drum cover and inside the drum.

[0054] 3) The coke discharged from the drum is screened with round hole sieves with diameters of 40mm and 10mm respectively. The part larger than 40mm must be punched by hand.

[0055] 4) When screening, we must strive to screen out the coke cleanly, but also avoid using excessive force to cause the coke to be hit and broken.

[0056] 5) Weigh the mass of coke of each particle size greater than 40mm, 40-10mm and less than 10mm respectively (accurate to 0.1kg). The difference between the sum and the mass of coke entering the drum is the loss. When the loss is not less than 0.3kg, the test is invalid. When it is less than 0.3kg, it is counted as the grade less than 10mm.

[0057] 6) Calculation of results

[0058] The crushing strength M40 is calculated according to formula (1):

[0059] M40=m1 / m*100%

[0060] The wear resistance M10 is calculated according to formula (2):

[0061] M10=m2 / m*100%

[0062] Where:

[0063] m——the mass of coke entering the drum, in kilograms (kg);

[0064] m1——the mass of coke larger than 40mm after exiting the drum, in kilograms (kg);

[0065] m2——The mass of coke less than 10mm after exiting the drum, in kilograms (kg);

[0066] The test results are rounded to one decimal place.

[0067] Example 2

[0068] 30kg of the mixture was mixed with 45wt% fat coal, 35wt% coking coal, 10wt% lean coal and 10wt% coal tar in a mixer, and then formed into briquette coal by a roller pelletizing machine. The apparent density of the briquette coal on dry basis was 1.17t / m3, the equivalent diameter was 12mm, the fineness of the coal was 82%, and the coal tar came from the residual ammonia water storage tank of the metallurgical coking plant.

[0069] 30kg of a mixture of loose coal for coking blended coal is prepared by mixing in a mixer in the proportions of 35wt% gas coal, 25wt% 1 / 3 coking coal, 11wt% fat coal, 11wt% coking coal, 10wt% lean coal and 8wt% long flame coal. Then, 12kg of formed coal and 28kg of the loose coal mixture for coking blended coal are weighed respectively, and the mixture is evenly mixed and then sent into a 40kg top-loading coke oven for coking. The coking conditions are coal loading at the furnace wall at 800°C, and the final coking temperature is that the center temperature of the coke cake reaches 950°C, which is maintained for 1 hour to obtain high-reactivity and high-strength heterogeneous coke for hydrogen-rich blast furnaces, wherein the bulk density of the loose coal is 0.8, the fineness is 77%, and the moisture is 10%.

[0070] The method described in Example 1 was used to measure the coke reactivity CRI of the high-reactivity and high-strength heterogeneous coke for hydrogen-rich blast furnace prepared in Example 2 to be 40.5%, the coke post-reaction strength CSR to be 63.9%, the cold strength M40 to be 83.3%, and the cold strength M10 to be 8.9%.

[0071] Example 3

[0072] 30kg of the mixture was mixed with 40wt% fat coal, 40wt% coking coal, 15wt% lean coal and 5wt% coal tar in a mixer, and then formed into briquette coal by a roller pelletizing machine. The apparent density of the briquette coal on dry basis was 1.15t / m3, the equivalent diameter was 14mm, the fineness of the coal material was 85%, and the coal tar came from the residual ammonia water storage tank of the metallurgical coking plant.

[0073] 30kg of a mixture of coking coal and bulk coal is prepared by mixing in a mixer according to the proportions of 5wt% gas coal, 50wt% 1 / 3 coking coal, 15wt% fat coal, 20wt% coking coal, 5wt% lean coal and 5wt% long flame coal. Then, 20kg of formed coal and 20kg of the coking coal and bulk coal mixture are weighed respectively, mixed evenly and sent into a 40kg top-loading coke oven for coking. The coking conditions are coal loading at the furnace wall at 800℃, the final coking temperature is that the center temperature of the coke cake reaches 950℃, and it is maintained for 1h to obtain high-reactivity and high-strength heterogeneous coke for hydrogen-rich blast furnaces, wherein the bulk coal has a bulk density of 0.75, a fineness of 80%, and a moisture content of 10%.

[0074] The coke reactivity CRI of the high-reactivity and high-strength heterogeneous coke for hydrogen-rich blast furnace obtained in Example 3 was measured by the method described in Example 1 to be 39.5%, the coke post-reaction strength CSR to be 68.6%, the cold strength M40 to be 87.5%, and the cold strength M10 to be 7.9%.

[0075] Comparative Example 4

[0076] 30kg of the mixture was mixed with 40wt% fat coal, 50wt% coking coal and 10wt% lean coal by a mixer, and then formed into briquette coal by a roller pelletizing machine. The apparent density of the briquette coal on dry basis was 1.12t / m3, the equivalent diameter was 18mm, and the fineness of the coal material was 82%.

[0077] 30kg of a mixture of loose coal for coking blended coal is prepared by mixing in a mixer in the proportions of 35wt% gas coal, 35wt% 1 / 3 coking coal, 15wt% fat coal, 5wt% coking coal and 10wt% lean coal. Then, 16kg of formed coal and 24kg of a mixture of loose coal for coking blended coal are mixed evenly and sent into a 40kg top-loading coke oven for coking. The coking conditions are coal loading at the furnace wall at 800°C, the final coking temperature is 950°C at the center of the coke cake, and it is maintained for 1 hour to obtain high-reactivity and high-strength heterogeneous coke for hydrogen-rich blast furnaces, wherein the bulk density of the loose coal is 0.80, the fineness is 78%, and the moisture is 10%.

[0078] The coke reactivity CRI of the high-reactivity and high-strength heterogeneous coke for hydrogen-rich blast furnace obtained in Example 3 was measured by the method described in Example 1 to be 35.6%, the coke post-reaction strength CSR to be 69.8%, the cold strength M40 to be 84%, and the cold strength M10 to be 8.7%.

[0079] Example 5

[0080] 30kg of the mixture was mixed with 45wt% fat coal, 35wt% coking coal, 10wt% lean coal and 10wt% coal tar in a mixer, and then formed into briquette coal by a roller pelletizing machine. The apparent density of the briquette coal on dry basis was 1.17t / m3, the equivalent diameter was 12mm, the fineness of the coal was 82%, and the coal tar came from the residual ammonia water storage tank of the metallurgical coking plant.

[0081] 30 kg of a mixture of loose coal for coking blended coal was prepared by mixing 35 wt% gas coal, 25 wt% 1 / 3 coking coal, 11 wt% fat coal, 11 wt% coking coal, 10 wt% lean coal, 7.9 wt% long flame coal and 0.1 wt% Fe-containing catalyst (ferroferric oxide, analytical grade) in a mixer, and then 12 kg of formed coal and 28 kg of the mixture of loose coal for coking blended coal were weighed respectively. After mixing evenly, the mixture was sent into a 40 kg top-loading coke oven for coking. The coking conditions were coal loading at 800°C on the furnace wall and the final coking temperature was 950°C at the center of the coke cake, which was maintained for 1 hour to obtain high-reactivity and high-strength heterogeneous coke for hydrogen-rich blast furnaces, wherein the bulk density of the loose coal was 0.8, the fineness was 77%, and the moisture content was 10%.

[0082] The method described in Example 1 was used to measure the coke reactivity CRI of the high-reactivity and high-strength heterogeneous coke for hydrogen-rich blast furnace prepared in Example 2 to be 39.4%, the coke post-reaction strength CSR to be 65.3%, the cold strength M40 to be 82.4%, and the cold strength M10 to be 9.8%.

[0083] Comparative Example 1

[0084] The difference from Example 1 is that the coal molding process is not used, but the coal types are directly mixed for coking. The same coal types and weight percentages as those in Example 1 are used, and the proportion is: 17.05wt% gas coal, 19.25wt% 1 / 3 coking coal, 20.15wt% fat coal, 25.4wt% coking coal, 8.6wt% lean coal, 5.5wt% long flame coal and 4.105wt% coal tar.

[0085] Weigh each type of coal according to the above proportion to obtain 40kg of a mixture, mix it evenly with a mixer and then send it into a 40kg test coke oven for coking. The coking conditions are coal loading at the furnace wall at 800°C, the final coking temperature is that the center temperature of the coke cake reaches 950°C, and it is maintained for 1 hour to obtain the coke of comparative example 1.

[0086] The coke reactivity CRI, measured by the method described in Example 1, was 43.5%, the coke post-reaction strength CSR was 42.5%, the cold strength M40 was 78.4%, and the cold strength M10 was 12.3%.

[0087] Comparative Example 2

[0088] The difference from Example 2 is that the coal molding process is not used, but the coal types are directly mixed for coking. The same coal types and weight percentages as those in Example 2 are used, and the proportion is 24.5wt% gas coal, 17.5wt% 1 / 3 coking coal, 17wt% fat coal, 14wt% coking coal, 10wt% lean coal, 14wt% long flame coal and 3wt% coal tar.

[0089] According to the above proportions, each type of coal is weighed to obtain 40 kg of a mixture, which is evenly mixed with a mixer and then sent into a 40 kg test coke oven for coking. The coking conditions are coal loading at the furnace wall at 800°C, and the final coking temperature is that the center temperature of the coke cake reaches 950°C, which is maintained for 1 hour to obtain the coke of Comparative Example 2.

[0090] The coke reactivity CRI, measured by the method described in Example 1, was 50.5%, the coke post-reaction strength CSR was 30.2%, the cold strength M40 was 72.4%, and the cold strength M10 was 15.3%.

[0091] Comparative Example 3

[0092] The difference from Example 3 is that the coal molding process is not used, but the coal types are directly mixed for coking. The same coal types and weight percentages as those in Example 3 are used, and the proportion is 2.5wt% gas coal, 25wt% 1 / 3 coking coal, 27.5wt% fat coal, 30wt% coking coal, 10wt% lean coal, 2.5wt% long flame coal and 2.5wt% coal tar.

[0093] Weigh each type of coal according to the above proportion to obtain 40kg of a mixture, mix it evenly with a mixer and then send it into a 40kg test coke oven for coking. The coking conditions are coal loading at the furnace wall at 800°C, the final coking temperature is that the center temperature of the coke cake reaches 950°C, and it is maintained for 1 hour to obtain the coke of Comparative Example 3.

[0094] The coke reactivity CRI was measured by the method described in Example 1 to be 28.5%, the coke post-reaction strength CSR was 60.2%, the cold strength M40 was 83.4%, and the cold strength M10 was 7.3%.

[0095] The coke reactivity of the high-reactivity and high-strength coke for hydrogen-rich blast furnaces prepared in Examples 1-4 of the present invention is 35.6-40.5%, and the strength of the coke after reaction is 63.9-69.8%, which can take into account both high reactivity and high strength. Compared with Examples 1 and 2, although the coke reactivity of Comparative Examples 1 and 2 is improved, the strength after reaction decreases significantly. Compared with Example 3, although the strength after reaction of Comparative Example 3 is similar to that of Example 3, the reactivity decreases significantly.

[0096] In summary, the present invention adopts formed coal and controls the ratio of formed coal and blended coal to produce a highly reactive and high-strength heterogeneous coke for hydrogen-rich blast furnaces, which includes high-strength coke obtained by carbonizing formed coal and high-reactivity coke obtained by carbonizing loose coking blended coal. The surfaces of the two parts are mutually infiltrated and fused together through the colloid formed during the coking process. Since the raw coal quality of these two parts of coke is essentially different, although there is mutual infiltration during the coking process, due to the high viscosity of the colloid, the two parts cannot be completely dissolved in each other to form a uniform body, so the coke formed by the two parts is called heterogeneous coke. Figure 2 As shown in the figure, the high-strength coke formed by the briquette in the hydrogen-rich blast furnace is protected by the coke formed by the external loose coal, and the strength is higher after the reaction; the coke formed by the carbonization of the loose coal preferentially reacts with CO 2 The coke can react with water vapor to improve the comprehensive reactivity and strength after the reaction compared with conventional coke, which can make the hydrogen-rich blast furnace run smoothly, improve the utilization rate of coal gas, and achieve the purpose of carbon reduction. The preparation method of the invention is simple to operate, has lower cost, and is suitable for large-scale production.

[0097] The selection range of the equivalent diameter of the molding coal in the embodiment is relatively small, and it is mainly an adjustment to the sample preparation method of the existing national standard. When coke is used for metallurgical production, the equivalent diameter of the molding coal can be increased to the range in the claims of this patent.

[0098] The above is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing heterogeneous coke for hydrogen-rich blast furnace, characterized in that: The method comprises mixing briquette coal and coking blend coal and then coking the mixture, wherein the briquette coal is 30-50wt% and the coking blend coal is 50-70wt% by weight. Wherein, the coking blend coal comprises, by weight percentage, 5-10% long flame coal, 5-35% gas coal, 25-50% 1 / 3 coking coal, 5-15% fat coal, 5-20% coking coal and 5-10% lean coal; The shaped coal is prepared from raw materials including fat coal, coking coal, lean coal and a binder; in terms of weight percentage, the fat coal is 35-45%, the coking coal is 35-50%, the lean coal is 5-20%, and the binder is 5-10%; the binder is one or two of coal tar and asphalt; The preparation method comprises the following steps: 1) Mix fat coal, coking coal, lean coal and binder raw materials evenly, and make briquette coal through a roller pelletizing machine. The apparent density of briquette coal on dry basis is 1.0t / m 3 ~1.2t / m 3 , the equivalent diameter is 10mm~50mm; 2) Mix gas coal, 1 / 3 coking coal, fat coal, coking coal, lean coal and long flame coal in a mixer according to the proportion to prepare a coking coal bulk material mixture; 3) After the above-mentioned briquette coal and the coking coal bulk material mixture are evenly mixed, they are sent to the top-loading coke oven for coking; the coking conditions are that the furnace wall is charged with coal at 800°C, the final coking temperature is that the center temperature of the coke cake reaches 950°C, and it is maintained for 1 hour to obtain high-reactivity and high-strength heterogeneous coke for hydrogen-rich blast furnace; The coke reactivity CRI of the heterogeneous coke for the hydrogen-rich blast furnace is 30% to 45%, the coke post-reaction strength CSR is 60% to 70%, the cold strength M40 is 82% to 89%, and the cold strength M10 is 5% to 9%.

2. The preparation method according to claim 1, characterized in that: In terms of weight percentage, the molding coal is 35-45wt%, and the coking blend coal is 55-65wt%.

3. The preparation method according to any one of claims 1 to 2, characterized in that: The coking coal has a fineness of 66-88%, and / or a moisture content of 10-12%.

4. The preparation method according to any one of claims 1 to 2, characterized in that: The coking blended coal also includes a catalyst containing Ca and / or Fe.

5. The preparation method according to claim 4, characterized in that: The content of the catalyst containing Ca and / or Fe is 0.1-1% based on the weight of the coking coal.

6. A heterogeneous coke for a hydrogen-rich blast furnace, characterized in that: The heterogeneous coke for hydrogen-rich blast furnace is prepared by the preparation method according to any one of claims 1 to 5.

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