Laboratory determination device and method for continuous degradation process of coke in hydrogen-rich blast furnace

Abstract

The invention discloses a laboratory determination device and method for the continuous degradation process of coke in a hydrogen-rich blast furnace, and relates to the technical field of blast furnace raw material detection. The device comprises a gas distribution system, a heating system and a material distributing and taking system, the gas distribution system achieves accurate gas proportioning through a plurality of gas steel cylinders and a water vapor generator, the heating system adopts a program temperature control hearth to simulate the temperature gradient of the blast furnace, and the material distribution system achieves stratified sampling through a conical material containing table and a discharging pipe. According to the experimental method, reducing gas components (N2, CO, CO2, H2 and H2O) and a temperature gradient (500-1350 DEG C) are regulated and controlled in stages, the working conditions of a preheating zone, an indirect reduction zone and a dripping zone of a blast furnace are simulated in sequence, and the continuous degradation process of coke under the hydrogen-rich condition is quantitatively characterized by combining gasification rate calculation (RC = (m1-m2) / m1 * 100%) and specific surface area change rate analysis (Sc = (S2-S1) / S1 * 100%).

Description

Technical Field

[0001] The present invention relates to blast furnace raw material detection, and in particular to a laboratory determination device and method for the continuous degradation process of coke in a hydrogen-rich blast furnace. Background Art

[0002] Coke, a core raw material in the blast furnace ironmaking process, primarily serves as a heat source, reducing agent, carburizing agent, and skeleton. During blast furnace operation, coke is subject to mechanical wear, load-bearing cracking, carburizing loss, chemical combustion losses, gasification reactions, and reduction losses. The extent and pattern of coke loss vary depending on the operating conditions within the blast furnace, necessitating different coke quality requirements for hydrogen-rich blast furnaces and traditional blast furnaces. Under hydrogen-rich conditions, coke gasification and melting loss within the blast furnace are not independent processes; rather, they interact and occur simultaneously. In a hydrogen-rich blast furnace, hydrogen indirectly reduces iron ore to generate H₂O vapor, which reacts with the coke to form C + H₂O(g) = 2CO(g). Increasing the H₂ content in the coal gas alters the coke degradation process. Therefore, the quality requirements for coke used in hydrogen-rich blast furnaces differ from those for conventional blast furnaces. The quality indicators for coke used in hydrogen-rich blast furnaces also differ from those for conventional blast furnaces. Therefore, it is necessary to re-evaluate the relationship between the hydrogen content of coal gas and coke quality in hydrogen-rich blast furnaces. This requires a more rational approach to studying the continuous degradation process of coke in hydrogen-rich blast furnaces and, based on this understanding of the continuous degradation process, to evaluate the quality of coke used in hydrogen-rich blast furnaces. Summary of the Invention

[0003] To achieve the above-mentioned objectives, the present invention provides a laboratory measurement device for the continuous degradation process of coke in a hydrogen-rich blast furnace, comprising: a gas distribution system, including multiple independent gas source supply units, a gas flow controller, a water vapor generator and a gas mixing pipeline with an insulation layer, the gas source supply unit includes at least a nitrogen source, a carbon monoxide source, a carbon dioxide source and a hydrogen source; a heating system, including a heating furnace body with a vertical furnace tube, a temperature detection unit and a programmed temperature control unit, the lower part of the furnace tube is provided with an air inlet interface and the upper part is provided with an exhaust interface; a material distribution and material collection system, including a conical supporting platform arranged in the constant temperature zone of the furnace tube, a vertical material discharge channel connected to the center of the conical supporting platform, and a multi-stage sampling container arranged outside the furnace tube; a gas permeation hole array is evenly distributed on the surface of the conical supporting platform, and the vertical material discharge channel is equipped with a controllable opening and closing mechanism.

[0004] Furthermore, the conical surface inclination angle of the conical bearing platform is 45-60 degrees, the diameter of the gas permeation hole is 0.5-1.5 mm, and the hole spacing is 3-5 times the hole diameter.

[0005] The present invention also provides a method for measuring the continuous degradation process of coke in a hydrogen-rich blast furnace, using the above-mentioned device, comprising the following steps:

[0006] (1) Sample preparation and loading:

[0007] The coke sample and iron ore are loaded on the conical supporting platform in alternating layers. The particle size of the coke is controlled at 20-25 mm, and the particle size of the iron ore is controlled at 15-18 mm.

[0008] (2) Staged reaction processing:

[0009] a) Preheating and activation stage: A mixed gas containing 4-6% water vapor is introduced, and the temperature is raised to 1000-1100°C at a rate of 8-12°C / min. The temperature is kept at this temperature for 15-25 minutes, and the first sample is collected;

[0010] b) Indirect reduction stage: switch to a dry mixed gas containing 4-6% hydrogen, continue heating to 1200-1250°C, hold for 15-25 minutes, and then collect the second sample;

[0011] c) High-temperature melting stage: using hydrogen-rich ternary mixed gas, heating to 1300-1400°C, keeping warm for 15-25 minutes, and then collecting the third sample;

[0012] (3) Performance parameter determination:

[0013] The coke gasification rate RC = (m1-m2) / m1×100% and the specific surface area change rate Sc = (S2-S1) / S1×100% of each stage are calculated respectively, where m1 and S1 are the initial mass and specific surface area, and m2 and S2 are the measured values after the reaction.

[0014] Furthermore, the mixed gas composition in the preheating and activation stage is as follows by volume: N2 45-55%, CO18-22%, CO2 18-22%, H2 3-5%, H2O 5-7%, and the total gas flow rate is maintained at 8-12 L / min.

[0015] Furthermore, the mixed gas composition in the indirect reduction stage is as follows by volume: N2 50-55%, CO2 0-25%, CO2 18-22%, H2 3-5%, and the water vapor content is kept below 1%.

[0016] Furthermore, the composition of the ternary mixed gas in the high-temperature melting stage is as follows by volume: N2 55-65%, CO 25-35%, H2 8-12%, and the heating rate is controlled at 5-8°C / min.

[0017] Furthermore, the loading mass ratio of the iron ore to the coke is (3-5):1, and the thickness of each layer is controlled at 20-30 mm.

[0018] Furthermore, before each sampling, nitrogen was introduced to replace the furnace atmosphere for 15-25 minutes, and the replacement pressure was maintained at a slightly positive pressure state of 0.008-0.015 MPa.

[0019] Furthermore, the specific surface area is determined by a nitrogen adsorption method. After each sampling, 3-5 groups of coke particles are randomly selected for crushing testing, and the arithmetic mean is taken as the measurement result.

[0020] Furthermore, during each stage of insulation, the furnace pressure is maintained within the range of ±5% of normal pressure, and the gas flow fluctuation is controlled within ±2% of the set value.

[0021] The present invention innovatively realizes the dynamic reproduction and precise detection of the coke degradation process in a hydrogen-rich blast furnace by constructing a multi-stage continuous reaction simulation system. The device adopts a material distribution and feeding system with a conical load-bearing platform and a vertical feeding channel. The conical air permeability design ensures the uniform penetration of the gas-solid reaction. The layered alternating loading method accurately simulates the actual distribution state of coke and iron ore in the blast furnace. Combined with the gradient temperature control and programmable gas ratio system, the continuous degradation process of coke in the preheating zone, indirect reduction zone and high-temperature melting zone is fully reproduced. The unique conical feeding structure and the controllable feeding mechanism realize the pollution-free separation and directional collection of samples at different reaction stages in a high-temperature environment, effectively avoiding the problems of material mixing and heat loss in traditional sampling methods.

[0022] The concept, specific structure and technical effects of the present invention will be further described below in conjunction with the accompanying drawings to fully understand the purpose, characteristics and effects of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the device used in the test of the present invention. DETAILED DESCRIPTION

[0024] The following describes several preferred embodiments of the present invention with reference to the accompanying drawings to make its technical content clearer and easier to understand. The present invention can be embodied in many different forms of embodiments, and the scope of protection of the present invention is not limited to the embodiments mentioned herein.

[0025] In the drawings, components with identical structures are denoted by the same reference numerals, and components with similar structures or functions are denoted by similar reference numerals. The size and thickness of each component shown in the drawings are arbitrary and are not limited by the present invention. For clarity, the thickness of components in some places in the drawings is appropriately exaggerated.

[0026] The present invention is used for the determination method of the continuous degradation process of hydrogen-rich blast furnace coke, and the test device used is as follows Figure 1 As shown, it includes a gas distribution system, a heating system, and a material distribution and reclaiming system. The gas distribution system includes an N2 cylinder 1, a CO cylinder 2, a CO2 cylinder 3, an H2 cylinder 4, a steam generator 5, a gas flow controller 6, and a gas pipe 7 with an insulation tape. The heating system includes a heating furnace 8, a furnace tube 17, a thermocouple 9, and a heating program control cabinet 10. The furnace tube 17 has an air inlet 12 at the bottom and an air outlet 13 at the top. The material distribution and reclaiming system includes a conical loading platform 15 located in the constant temperature zone of the furnace tube 17 and a discharge pipe 14 connected to the center of the conical loading platform 15. The conical loading platform 15 has air holes 16 on its conical surface. During measurement, the sample is stacked on the conical loading platform 15 and can be discharged from the conical loading platform 15 into sampling cups A, B, or C outside the furnace tube 17 through the discharge pipe 14.

[0027] In one embodiment, the following steps are used to perform the test:

[0028] (1) Sample preparation and loading

[0029] a. Sample preparation: The iron ore sample weighs 100g and has a particle size of 16mm. The mass of each coke sample m1 is 24g and has a particle size of 23mm. Twelve coke pellets are taken from the coke sample, with 3 pellets in each group. The coke is then ground into fine powder in four groups and placed in a N2 adsorption instrument for specific surface area measurement. The average of the four measurement results is taken as the measured value of the coke specific surface area S1. The average value of the measurement results is 2.9cm 2 / g;

[0030] b. The coke sample and iron ore were loaded into the conical charging station 15 in the furnace tube 17 in the order of coke - iron ore - coke - iron ore. The iron ore sample was 50 g; the coke sample was 12 g.

[0031] (2) Test:

[0032] a. Check the air tightness of the gas line. Introduce N2 to replace the furnace gas for 20 minutes. Set the pressure in the furnace tube to 0.01 MPa to achieve a slightly positive pressure in the furnace. Start heating at a rate of 10°C / min to 500°C and hold for 30 minutes.

[0033] b. Switch the N2 flow to a reducing gas with a total flow rate of 10 L / min. The flow rates of the various components are: N2: 5 L / min, 50% by volume; CO: 2 L / min, 20% by volume; CO2: 2 L / min, 20% by volume; H2: 0.4 L / min, 4% by volume; and H2O: 0.6 L / min, 6% by volume. Continue heating to 1000°C. After 20 minutes of holding and sufficient reaction, open the discharge pipe 14 and release the coke sample into the first sample cup A. The upper portion of the cup is taken as the first sample, and the lower portion is discarded. This first sample represents the reaction of coke in the blast furnace preheat zone, simulating the initial dehydration and surface activation process of coke. A gas mixture of 50% N2 + 20% CO + 20% CO2 + 4% H2 + 6% H2O is used to induce the initial gasification reaction.

[0034] c. The remaining samples continue to be placed in the high-temperature furnace. Heat to 1000°C in a 100% N2 atmosphere, and the N2 introduced is switched to a reducing gas with a total flow rate of 10L / min. The flow rates of the components are N2: 5.3L / min, 53% by volume, CO: 2.3L / min, 23% by volume, CO2: 2L / min, 20% by volume, H2: 0.4L / min, 4% by volume, and continue heating to 1200°C. After keeping warm for 20 minutes to fully react, open the discharge pipe 14, release the coke sample at this time into the second sample cup B, and take the upper material in the cup as the second sample, and discard the bottom material. The second sample corresponds to the indirect reduction zone, and the H2O content is reduced to 4%, and the CO ratio is increased to 23%, simulating the coke characteristics under hydrogen-rich conditions.

[0035] d. The remaining samples are placed in a high-temperature furnace. Heat to 1200°C in a 100% N2 atmosphere, and switch the N2 introduced to a reducing gas with a total flow rate of 10L / min, N2 6L / min, 60% by volume, CO 3L / min, 30% by volume, and H2 1L / min, 10% by volume; continue heating to 1350°C. After 20 minutes of insulation for full reaction, open the discharge pipe 14 and release the coke sample into the first sample cup A. Take the upper material in the cup as the third sample, and discard the bottom material. This third sample corresponds to the high-temperature zone and uses a ternary gas of 60% N2 + 30% CO + 10% H2 to simulate the ultimate melting loss behavior of coke in the dripping zone.

[0036] (3) Calculation of coke gasification rate

[0037] a. Take out the coke sample in step 2 (b), weigh it to 10.7g, and calculate the gasification rate R of the coke as follows: C :

[0038]

[0039] Where m1 is the mass of coke before the test (g); m2 is the remaining mass of coke after the test (g).

[0040] The specific surface area of the coke sample in step 2(b) was determined to be 4.9 cm 2 / g coke specific surface area change rate Sc:

[0041]

[0042] Where S1 is the specific surface area of coke before the test (mm 2 / g); S2 is the specific surface area of the coke after the test (mm 2 / g).

[0043] b. Take out the coke sample in step 2 (c), weigh 8.4g, and calculate the coke gasification rate R as follows: C :

[0044]

[0045] Where m1 is the mass of coke before the test (g); m2 is the remaining mass of coke after the test (g).

[0046] The specific surface area of the coke sample in step 2(c) was determined to be 7.3 cm 2 / g coke specific surface area change rate Sc:

[0047]

[0048] Where S1 is the specific surface area of coke before the test (mm 2 / g); S2 is the specific surface area of the coke after the test (mm 2 / g).

[0049] b. Take out the coke sample in step 2 (d), weigh 8g, and calculate the coke gasification rate R as follows: C :

[0050]

[0051] Where m1 is the mass of coke before the test (g); m2 is the remaining mass of coke after the test (g).

[0052] The specific surface area of the coke sample in step 2(d) was determined to be 8 cm 2 / g coke specific surface area change rate Sc:

[0053]

[0054] Where S1 is the specific surface area of coke before the test (mm2 / g); S2 is the specific surface area of the coke after the test (mm 2 / g).

[0055] The above describes in detail the preferred embodiments of the present invention. It should be understood that those skilled in the art can make numerous modifications and variations based on the concepts of the present invention without inventive effort. Therefore, any technical solutions that can be derived by those skilled in the art through logical analysis, reasoning, or limited experimentation based on the concepts of the present invention and the prior art should be within the scope of protection defined by the claims.

Claims

1. A laboratory device for measuring the continuous degradation process of coke in a hydrogen-rich blast furnace, characterized in that: include: A gas distribution system comprising a plurality of independent gas supply units, a gas flow controller, a steam generator and a gas mixing pipeline with an insulation layer, wherein the gas supply units include at least a nitrogen source, a carbon monoxide source, a carbon dioxide source and a hydrogen source; The heating system comprises a heating furnace body having a vertical furnace tube, a temperature detection unit and a programmable temperature control unit. The furnace tube is provided with an air inlet interface at the bottom and an exhaust interface at the top; The material distribution and reclaiming system includes a conical supporting platform arranged in the constant temperature zone of the furnace tube, a vertical material discharge channel connected to the center of the conical supporting platform, and a multi-stage sampling container arranged outside the furnace tube; the surface of the conical supporting platform is evenly distributed with an array of gas permeable holes, and the vertical material discharge channel is equipped with a controllable opening and closing mechanism.

2. The measuring device according to claim 1, wherein The conical surface inclination angle of the conical bearing platform is 45-60 degrees, the diameter of the gas permeation hole is 0.5-1.5 mm, and the hole spacing is 3-5 times the hole diameter.

3. A method for measuring the continuous degradation process of coke in a hydrogen-rich blast furnace, characterized in that: The device according to any one of claims 1 to 2 comprises the following steps: (1) Sample preparation and loading: The coke sample and iron ore are loaded on the conical supporting platform in alternating layers. The particle size of the coke is controlled at 20-25 mm, and the particle size of the iron ore is controlled at 15-18 mm. (2) Staged reaction processing: a) Preheating and activation stage: A mixed gas containing 4-6% water vapor is introduced, and the temperature is raised to 1000-1100°C at a rate of 8-12°C / min. The temperature is kept at this temperature for 15-25 minutes, and the first sample is collected; b) Indirect reduction stage: switch to a dry mixed gas containing 4-6% hydrogen, continue heating to 1200-1250°C, hold for 15-25 minutes, and then collect the second sample; c) High-temperature melting stage: using hydrogen-rich ternary mixed gas, heating to 1300-1400°C, keeping warm for 15-25 minutes, and then collecting the third sample; (3) Performance parameter determination: The coke gasification rate RC = (m1-m2) / m1×100% and the specific surface area change rate Sc = (S2-S1) / S1×100% of each stage are calculated respectively, where m1 and S1 are the initial mass and specific surface area, and m2 and S2 are the measured values after the reaction.

4. The measuring method according to claim 3, wherein The mixed gas composition in the preheating and activation stage is as follows by volume: N2 45-55%, CO 18-22%, CO2 18-22%, H2 3-5%, H2O 5-7%, and the total gas flow rate is maintained at 8-12 L / min.

5. The measuring method according to claim 3, wherein The mixed gas composition in the indirect reduction stage is as follows by volume: N2 50-55%, CO 20-25%, CO2 18-22%, H2 3-5%, and the water vapor content is kept below 1%.

6. The measuring method according to claim 3, wherein The composition of the ternary mixed gas in the high-temperature melting stage is as follows: N255-65%, CO 25-35%, H28-12% by volume, and the heating rate is controlled at 5-8°C / min.

7. The measuring method according to claim 3, wherein The loading mass ratio of the iron ore to the coke is (3-5):1, and the thickness of each layer is controlled at 20-30 mm.

8. The measuring method according to claim 3, wherein Before each sampling, nitrogen was introduced to replace the furnace atmosphere. The replacement time was 15-25 minutes, and the replacement pressure was maintained at a slightly positive pressure state of 0.008-0.015 MPa.

9. The measuring method according to claim 3, wherein The specific surface area is determined by a nitrogen adsorption method. After each sampling, 3-5 groups of coke particles are randomly selected for crushing and testing, and the arithmetic mean value is taken as the measurement result.

10. The assay method according to any one of claims 3 to 9, characterized in that During each stage of insulation, the furnace pressure is maintained within the range of normal pressure ±5%, and the gas flow fluctuation is controlled within ±2% of the set value.

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