Method for improving reactivity of lump coal for blast furnace
Modulation of smokeless block coal by modulating modulation of modulator and pulsed magnetic field/low temperature field coupling function solves the problem of poor reactivity of high-quality anthracite, improves its application performance and strength in blast furnaces, and achieves efficient reaction performance improvement and strength maintenance.
Patent Information
- Application Number
- CN202411359676.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-27
- Publication Date
- 2025-01-03
AI Technical Summary
The poor reactivity and low strength of high-quality anthracite in blast furnaces limit its application, and it is difficult to effectively replace traditional coke dirt with alternative materials.
By preparing modifiers and using pulsed magnetic field/low-temperature field coupling to interact modulate smokeless block coal, its surface and internal structure is improved, reactivity is improved and strength is maintained. The modifier consists of a mixture of super-fine coal and a polar solvent, prepared by solvent heat extraction technology, and is sprayed, soaked and prepared in a vacuum dryer and a box heating furnace.
It effectively improves the reaction performance and strength of coal, and the magnetic field accelerates the interaction between the modifier and the block coal. The sensible heat/low-temperature gas/water vapor provided by the low-temperature field has the advantage of price, the process is safe and simple, and has good application prospects.
Smart Images
Figure CN119242357A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of blast furnace fuel, and particularly relates to a method for improving the reactivity of lump coal used in blast furnaces. Background Art
[0002] In blast furnace hot metal production, the traditional use of diced coke (coke) is gradually being replaced by other alternatives due to cost and resource constraints. The use of lump coal mixed with iron-containing charge materials has become a new option. However, high-quality anthracite is generally less reactive and has lower strength, which limits its use in blast furnaces. Summary of the Invention
[0003] In response to the above problems, the present invention proposes a method for improving the reactivity of lump coal for blast furnaces, by adjusting the surface and internal shallow defect structure of the coal to improve its reactivity and maintain its strength.
[0004] The present invention adopts the following technical solutions: A method for improving the reactivity of lump coal for blast furnaces comprises the following steps: The first step is to prepare a modifier; The second step is to select the target smokeless lump coal for blast furnace; The third step is to sprinkle and infiltrate the selected smokeless lump coal with a modifier; The fourth step is the interactive modulation of the modifier and smokeless lump coal under the coupling of pulsed magnetic field / low temperature field.
[0005] Furthermore, the modifier comprises a mixed solution of ultra-clean coal and a polar solvent with low viscosity and high wettability in a volume ratio of 1:10-1:15, and the polar solvent comprises ethanol or acetone.
[0006] Furthermore, the preparation of the modifier adopts solvent thermal extraction technology, including the following steps: in a KCFD type reactor, the precursor is bituminous coal and the organic solvent is N-methylpyrrolidone, and extraction is carried out in a KCFD type reactor at a solid-liquid ratio of 8g / 400ml. The extraction temperature is 350°C, the extraction time is 1h, and the extraction pressure is 1.5-1.8MPa. After the extraction is completed, liquid one is obtained, and liquid one is filtered to obtain liquid two, which is a mixture of bituminous coal, super clean coal and N-methylpyrrolidone. A polar solvent is added to liquid two, mixed evenly, and a modifier is obtained.
[0007] Furthermore, the size of the smokeless coal is 15-30 mm, the ash content is not higher than 11%, and the crushing strength is: M 10-20 ≥80%, post-reaction strength CSR≥50%.
[0008] Furthermore, the showering and infiltration steps of the smokeless coal are as follows: after immersing the smokeless coal in the modifier for 2 minutes, the smokeless coal with the modifier on the surface is vacuumed using a vacuum dryer.
[0009] Furthermore, the interactive modulation steps of the modifier and the smokeless lump coal under the coupling action of the pulsed magnetic field / low-temperature field are as follows: the smokeless lump coal treated in the third step is placed in a glass tube in an argon atmosphere, the glass tube is placed in a box-type heating furnace, an energized solenoid is wrapped around the outside of the glass tube, the energized solenoid is externally connected to a tunable pulsed DC power supply, and the energized solenoid is used to provide a magnetic field environment; the box-type heating furnace heats the sample to 80-100°C, the current range is 100-400mA, and the processing time is 20 minutes.
[0010] The beneficial effects of the present invention are as follows: By using the method of the present invention, the surface functional groups and the internal shallow defect structure of the coal are effectively improved, thereby improving its reaction performance and maintaining its strength.
[0011] This invention utilizes pulsed magnetic field / low-temperature field coupling modulation, which accelerates the interaction between the modifier and the lump coal matrix on both temporal and spatial scales. The magnetic field intensity can be controlled and adjusted based on the magnitude of the current. In industrial practice, the low-temperature field can be provided by sensible heat, low-temperature coal gas, or steam recovered from steel mills. This offers significant cost advantages, a safe and simple process, and promising application prospects. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Figure 1 Schematic diagram of the interactive modulation between modifier and lump coal under the coupling of pulsed magnetic field / low temperature field; Figure 2 This is a microscopic diagram of the interaction modulation between the modifier and lump coal under the action of the coupling field; Figure 3 is the relationship between the thickness of the infiltration zone (d, micrometers) and the reaction time (t, minutes), reaction temperature (T, degrees Celsius) and magnetic field intensity (M, mA); Among them: 1-energized solenoid; 2-glass tube; 3-modifier@lump coal; 4-rubber plug; 5-box-type heating furnace; 6-DC power supply; 7-modifier; 8-lump coal matrix; 9-liquid-solid interface; 10-solidification layer; 11-microcrack; 12-crack dissolution zone. DETAILED DESCRIPTION
[0013] A method for improving the reactivity of lump coal for blast furnaces, characterized by comprising the following steps: The first step is to prepare a modifier; The second step is to select the target smokeless lump coal for blast furnace; The third step is to sprinkle and infiltrate the selected smokeless lump coal with a modifier; The fourth step is the interactive modulation of the modifier and smokeless lump coal under the coupling of pulsed magnetic field / low temperature field.
[0014] Among them, (1) the preparation of the modifier adopts solvent thermal extraction technology, and the preparation process is carried out in a KCFD type reactor. The precursor is bituminous coal, the organic solvent is NMP (N-methylpyrrolidone), the solid-liquid ratio is 8g / 400ml, the extraction temperature and time are 350 degrees Celsius and 1 hour respectively. The extraction pressure is controlled in the range of 1.5Mpa~1.8Mpa. After the test, liquid 1 is taken out from the reactor, and the liquid 1 is further filtered to obtain liquid 2. Liquid 2 is a mixture of bituminous coal HPC (super clean coal) and NMP. In order to reduce the viscosity of liquid 2 and facilitate subsequent atomization spraying, a certain volume of 75% ethanol is mixed into liquid 2 to obtain the modifier. The volume ratio of liquid 2 to ethanol solution is controlled in the range of 1:10 to 1:15. This ratio can ensure that the modifier has good sprayability.
[0015] (2) Optimization and pretreatment of target smokeless lump coal for blast furnaces High-quality Jincheng anthracite lump coal was initially selected as a replacement for coke in blast furnaces. The anthracite lump coal from the Sihe Mine (Jincheng) exhibits excellent crushing and abrasion resistance. Conversion tests indicate that the fraction of undersize less than 5 mm for an initial 10-20 mm lump coal is 7.88%. To quantify the impact of subsequent processing on the lump coal, the anthracite lump coal was formed into 20 mm x 20 mm x 20 mm cubes. In industrial practice, anthracite lump coal with a size range of 15 mm to 30 mm can be obtained through crushing and screening. The CRI and CSR of the Sihe anthracite lump coal, measured according to the national standard GB / T4000-2017, are 20.3% and 56.3%, respectively.
[0016] (3) Using modifiers to sprinkle and soak the selected smokeless lump coal with high compressive and wear resistance Small cubes of coal were immersed in the modifier for two minutes to ensure the modifier was wetted onto the surface of the coal. The coal, with the modifier on its surface, was then vacuumed in a vacuum dryer to remove air from the surface cracks (defects). At the same time, a small amount of modifier filled the spaces within the microcracks (micropores) within the coal.
[0017] (4) Interactive modulation of modifier and lump coal under pulsed magnetic field / low temperature field coupling To accelerate the volatilization of alcohol in the modifier and the interaction between HPC@NMP and lump coal, the sample was heated to 80-100 degrees Celsius in a box-type heating furnace. An energized solenoid was used to provide a magnetic field environment for the sample. Figure 1Schematic diagram of the interaction between the modifier and lump coal under the pulsed magnetic field / low-temperature field coupling. The energized solenoid consists of 10 turns of 2mm diameter copper wire, connected to an external tunable pulsed DC power supply. The current is controlled within a range of 100mA to 400mA. Effective dissolution and drying of the lump coal surface modifier is achieved by standing at 85°C and a current of 100mA for 20 minutes.
[0018] Figure 2 Schematic diagram of the interaction between the modifier and lump coal under the action of a coupled field: Process ①→② shows the microscopic conditions on the lump coal matrix surface from before the reaction to after the interaction, which increases the number of active sites on the lump coal surface. Process ③→④ shows the dissolution and penetration of the modifier into the microcracks of the lump coal. Under the action of the coupled field, the modifier repairs local defects in the lump coal matrix, providing important structural support for the lump coal to maintain its strength after the reaction.
[0019] Figure 3 There is a quantitative relationship between the thickness of the infiltration zone (d, micrometers) and the reaction time (t, minutes), reaction temperature (T, degrees Celsius) and magnetic field strength (M, mA). It can be expressed by the following formula: d=15645.9263·T-22146.0330·M+48135.5633·t+120.3925·T·M-1383.8299·T·t+625.7581·M·t-0.0397·T 2 -0.0006·M 2 -0.0732·t 2 .
[0020] Example 1 According to the national standard GB / T4000-2017, Sihe anthracite lump coal was crushed and screened to produce nearly spherical anthracite particles with a size of 23-25 mm. A modifier was evenly sprayed on the surface of the anthracite at a rate of 40 mL per 200 g of anthracite. The sample was then placed in a vacuum desiccator at a vacuum of 50 mbar for 30 minutes. The modifier and the lump coal were then interactively modulated using a pulsed magnetic field coupled with a low-temperature field. The reaction time (t, minutes), reaction temperature (T, degrees Celsius), and magnetic field intensity (M, mA) were 30 minutes, 85°C, and 150 mA, respectively. The CRI and CSR of the treated samples were measured according to the national standard GB / T4000-2017. The results showed that the CRI increased to 23.3%, while the CSR remained virtually unchanged at 56.0%.
[0021] Example 2 According to the national standard GB / T4000-2017, Sihe anthracite lump coal was crushed and screened to produce approximately spherical anthracite particles with a size of 23-25 mm. A modifier was evenly sprayed on the surface of the anthracite at a rate of 40 mL per 200 g of anthracite. The sample was then placed in a vacuum desiccator at a vacuum of 50 mbar for 30 minutes. The modifier and the lump coal were then interactively modulated using a pulsed magnetic field coupled with a low-temperature field. The reaction time (t, minutes), reaction temperature (T, degrees Celsius), and magnetic field intensity (M, mA) were 40 minutes, 100°C, and 250 mA, respectively. The CRI and CSR of the treated samples were measured according to the national standard GB / T4000-2017. The results showed that the CRI increased to 27.6%, while the CSR slightly decreased to 54.5%.
Claims
1. A method for improving the reactivity of lump coal for blast furnace, characterized in that: The steps include: The first step is to prepare a modifier; The second step is to select the target smokeless lump coal for blast furnace; The third step is to sprinkle and infiltrate the selected smokeless lump coal with a modifier; The fourth step is the interactive modulation of the modifier and smokeless lump coal under the coupling effect of pulse magnetic field / low temperature field.
2. A method for improving the reactivity of lump coal for blast furnace according to claim 1, characterized in that: The modifier comprises a mixed solution of ultra-clean coal and a polar solvent with low viscosity and high wettability in a volume ratio of 1:10-1:15, and the polar solvent comprises ethanol or acetone.
3. A method for improving the reactivity of lump coal for blast furnace according to claim 2, characterized in that: The preparation of the modifier adopts solvent thermal extraction technology, which includes the following steps: in a KCFD type reactor, the precursor is selected from bituminous coal and the organic solvent is N-methylpyrrolidone, and extraction is carried out in the KCFD type reactor at a solid-liquid ratio of 8g / 400ml, the extraction temperature is 350°C, the extraction time is 1h, and the extraction pressure is 1.5-1.8MPa. After the extraction, liquid one is obtained, and liquid one is filtered to obtain liquid two, wherein the liquid two is a mixture of bituminous coal, super clean coal and N-methylpyrrolidone, and a polar solvent is added to the liquid two, and mixed evenly to obtain the modifier.
4. A method for improving the reactivity of lump coal for blast furnace according to claim 1, characterized in that: The size of the smokeless lump coal is 15-30mm, the ash content is not higher than 11%, and the crushing strength is: M 10-20 ≥80%, post-reaction strength CSR≥50%.
5. A method for improving the reactivity of lump coal for blast furnace according to claim 1, characterized in that: The steps of showering and infiltrating the smokeless coal lump are as follows: after the smokeless coal lump is immersed in the modifier for 2 minutes, the smokeless coal lump with the modifier on the surface is vacuumed by using a vacuum dryer.
6. A method for improving the reactivity of lump coal for blast furnace according to claim 1, characterized in that: The interactive modulation steps of the modifier and the smokeless lump coal under the pulse magnetic field / low temperature field coupling are as follows: the smokeless lump coal treated in the third step is placed in a glass tube in an argon atmosphere, the glass tube is placed in a box-type heating furnace, an energized solenoid is wound around the outside of the glass tube, the energized solenoid is externally connected to a tunable pulse DC power supply, and the energized solenoid is used to provide a magnetic field environment; the box-type heating furnace heats the sample to 80-100°C, the current range is 100-400mA, and the processing time is 20min.