CN110760358A - Method for manufacturing coal aggregate of direct smelting reduction furnace - Google Patents
Method for manufacturing coal aggregate of direct smelting reduction furnace Download PDFInfo
- Publication number
- CN110760358A CN110760358A CN201911116224.8A CN201911116224A CN110760358A CN 110760358 A CN110760358 A CN 110760358A CN 201911116224 A CN201911116224 A CN 201911116224A CN 110760358 A CN110760358 A CN 110760358A
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- coal
- smelting reduction
- reduction furnace
- aggregate
- fine coal
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- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
- C10L5/00—Solid fuels
- C10L5/02—Solid fuels such as briquettes consisting mainly of carbonaceous materials of mineral or non-mineral origin
- C10L5/06—Methods of shaping, e.g. pelletizing or briquetting
- C10L5/08—Methods of shaping, e.g. pelletizing or briquetting without the aid of extraneous binders
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- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Geology (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Organic Chemistry (AREA)
- Manufacture Of Iron (AREA)
Abstract
A method for manufacturing coal aggregate in a direct smelting reduction furnace belongs to the field of methods for manufacturing coal aggregate, and is characterized in that: agglomerating the fine coal by heating to a temperature of 600 ℃ or more for 5 minutes or more; the fine coal has a free swell index of 3.0 or more and a particle diameter of 8mm or less. The tendency of coal to self-aggregate due to its self-adhesive properties during thermal decomposition is utilized, and therefore, fine coal can be agglomerated at high temperatures in a simple manner; anthracite coal or low free expansion coal in an amount of 70% or less is mixed and maintained at a temperature of 600 c or more for 5 minutes or more, thereby manufacturing a coal aggregate for a direct smelting reduction furnace.
Description
Technical Field
The invention belongs to the field of a method for manufacturing coal aggregates, and particularly relates to a method for manufacturing coal aggregates in a direct smelting reduction furnace.
Background
Coal used as an energy source in a direct smelting reduction furnace must have a uniform particle size (8-35 mm). However, 50% or more of the coal supplied in the direct smelting reduction furnace is fine coal having a particle size of 8mm or less. When such fine coal is put into the smelting furnace, it flows into the generator gas line, and thus the fine coal becomes useless, that is, the supplied ordinary coal is classified into particle sizes, and agglomerates having a size of 8mm or more are put into the smelting reduction furnace after being dehydrated. However, fine coal having a particle size of 8mm or less cannot be used. Therefore, if the particle size of the fine coal is 8mm or less for use in the smelting reduction process, it must be first agglomerated. In the prior art, a method of agglomerating fine coal is disclosed, in which fine coal is injected into a pipe in which high temperature flows, thereby agglomerating the fine coal. However, in the above-mentioned coagulation method, there is a disadvantage that a high-temperature gas supply device is required, and the temperature rise rate must be 100 ℃/sec.
Disclosure of Invention
The present invention has been made to solve the above problems, and an object of the present invention is to provide a method for producing a coal aggregate in a direct smelting reduction furnace.
The method for producing coal aggregate in a direct smelting reduction furnace according to the present invention aggregates fine coal by heating the fine coal to a temperature of 600 ℃ or higher for 5 minutes or longer; the fine coal has a free swell index of 3.0 or more and a particle diameter of 8mm or less.
Further, in the method for producing a coal aggregate in a direct smelting reduction furnace according to the present invention, the fine coal is agglomerated at a temperature of 650-.
Further, in the method for producing a coal aggregate in a direct smelting reduction furnace according to the present invention, the fine coal is obtained from a direct iron ore smelting reduction process. In which anthracite or low free expansion coal having a low self expansion index is mixed with fine coal and the mixture is agglomerated at high temperature, thereby converting low quality coal to a useful purpose.
The method for producing a coal aggregate in a direct smelting reduction furnace according to the present invention mixes fine coal with low free swelling coal or anthracite coal, the fine coal being 70% by weight or less, and agglomerates the fine coal mixture by heating it to a temperature of 600 ℃ or more for 5 minutes or more; the fine coal has a free melt index of 3.0 or more and a particle size of 8mm or more.
Further, in the method for producing a coal aggregate in a direct smelting reduction furnace according to the present invention, the fine coal is agglomerated at a temperature of 650-.
Further, in the method for producing a coal aggregate in a direct smelting reduction furnace according to the present invention, the fine coal is obtained from a direct iron ore smelting reduction process.
The method for manufacturing the coal aggregate of the direct smelting reduction furnace utilizes the tendency of self-aggregation of coal due to self-adhesive property in the thermal decomposition process, so that the fine coal can be aggregated at high temperature in a simple manner; anthracite coal or low free expansion coal in an amount of 70% by weight or less is mixed and maintained at a temperature of 600 c or more for 5 minutes or more, thereby manufacturing a coal aggregate for a direct smelting reduction furnace.
Detailed Description
The method for producing the coal aggregate in the direct smelting reduction furnace according to the present invention will be described in detail below with reference to examples.
The pulverized coal-agglomerated coal of the present invention is ordinary coal having a particle diameter of 8mm or less and a self-expansion index of 3.0 or more. Ordinary coal is obtained from a direct smelting reduction process. If the coal aggregate in the direct iron melting reduction furnace is manufactured according to the present invention, the fine coal is maintained at 600 ℃ for 5 minutes or more. Because, if the temperature (agglomeration temperature) is kept below 600 ℃, the coal aggregate is easily broken and the compressive strength required for the direct smelting reduction furnace cannot be obtained. The higher the condensation temperature, the higher the compressive strength. In particular, excellent compressive strength is obtained at temperatures of 650-800 ℃. Therefore, if excellent compressive strength is to be obtained, a holding temperature of 650-. Further, in the agglomeration process of the fine coal, the retention time (agglomeration time) should be 5 minutes or more. That is, if it is maintained for less than 5 minutes, the compressive strength is lowered. Meanwhile, the coal aggregate may also be produced in such a manner that the fine coal is mixed with low free expansion coal having low viscosity or with anthracite coal having no viscosity, and the mixture is maintained at 600 ℃ or more. For 5 minutes or more.
The mixing proportion of the low free expansion coal or anthracite coal must be 70% by weight, and if it exceeds 70%, compressive strength suitable for the direct smelting reduction furnace cannot be obtained. Therefore, according to the present invention, the fine coal is aggregated, thereby producing coal aggregates having a particle size of 8mm or more. Coal agglomerates here mean agglomerates obtained from fine coal by agglomeration.
In the technical scheme of the invention, waste heat generated from the smelting reduction furnace is used as a heat source. The high quality coal is preferably obtained from a direct iron melt reduction process and the produced coal agglomerates are used in a direct smelting reduction furnace. Typically, the reducing gas produced by the smelting reduction furnace has a temperature of about 1100 ℃. The optimum temperature required for the upper shaft furnace is approximately 850 ℃. Thus, about 20% of the reducing gas at about 850 ℃ is cooled to about 50 ℃ during the passage through the venturi scrubber before entering the shaft furnace. The recirculated cooling gas flows into the generator gas line and thus serves as a temperature control device for the reducing gas. The high temperature fine coal agglomerating device is installed upstream of the venturi scrubber. By using the heat of the high-temperature (about 850 ℃) reducing gas, the fine coal is aggregated according to the present invention.
Further, the high-temperature coal agglomerates obtained by the above-described method may be charged into the top of the direct iron ore smelting reduction furnace. A coal aggregate for a direct smelting reduction furnace is produced by using waste heat generated in the smelting reduction furnace as a heat source and using fine coal obtained from the direct iron ore smelting reduction furnace. In this case, the fine coal of less than 8mm obtained from the direct smelting reduction furnace can be converted into a useful purpose. The fine coal may be agglomerated by mixing it with low free expansion coal or anthracite. Furthermore, not only the waste heat of the reducing gas can be used for useful purposes, but also the coal agglomerates heated to a high temperature (about 600 ℃ or higher) can be placed directly on top of the direct iron. The heating heat required in the case of using normal temperature coal can be saved. The invention will now be described on the basis of a practical example.
Two types of fine coal were obtained from direct iron ore melt reduction process and (mountain) coal with a free swell index of 4.5 and a particle size of 8mm was placed in the crucible. These crucibles were then placed in an electric furnace which had been heated to 850 ℃. Their compressive strength was then measured at each holding interval of 5 to 30 minutes. If the holding interval is more than 5 minutes, sufficient compressive strength can be obtained. That is, the compressive strength obtained is greater than 5Kg/cm2, which is the minimum compressive strength available in a direct iron ore smelting reduction process.
The coal was held at intervals of 10 minutes, and the coal was coagulated by changing the holding temperature (reaction temperature) from 50 ℃ to 600 ℃ and 850 ℃. The compressive strength was then measured at the end of each 50 ℃ temperature interval; when the temperature is maintained at 600 ℃, sufficient strength epsilon strength can be obtained; the reaction temperature was fixed at 850 ℃ and the reaction interval was fixed at 10 minutes. In addition, the anthracite coal is gradually mixed by 10% from 20% to 70%, thereby agglomerating the mixture coal. Thus, as the mixing amount of anthracite increases, the compressive strength decreases, but up to 70%, as measured at every 10% increase in anthracite, is sufficient for use in the iron ore smelting reduction process.
According to the technical scheme of the invention, the pulverized coal obtained by the direct iron ore smelting reduction process can be condensed in a simple manner. Anthracite coal, which has no sticky or low expansion coal, can be mixed with pulverized coal, and energy utilization is performed in an advantageous manner. In the case of agglomeration of fine coal of 8mm or less obtained by the direct smelting reduction process according to the present invention, anthracite coal having a low free expansion index or low free expansion coal can be utilized, thereby making it possible; even low quality coal can be used.
Claims (6)
1. A method for producing a coal aggregate in a direct smelting reduction furnace, comprising: agglomerating the fine coal by heating to a temperature of 600 ℃ or more for 5 minutes or more; the fine coal has a free swell index of 3.0 or more and a particle diameter of 8mm or less.
2. The method for producing coal aggregate for a direct smelting reduction furnace according to claim 1, wherein: the fine coal agglomerates at a temperature of 650-850 ℃.
3. The method for producing coal aggregate for a direct smelting reduction furnace according to claim 1, wherein: the fine coal is obtained from a direct iron ore smelting reduction process.
4. A method for producing a coal aggregate in a direct smelting reduction furnace, comprising: mixing fine coal with low free swelling coal or anthracite, the content of the fine coal being 70% or less, and agglomerating the fine coal mixture by heating it to a temperature of 600 ℃ or more for 5 minutes or more; the fine coal has a free melt index of 3.0 or more and a particle size of 8mm or more.
5. The method of manufacturing coal aggregate for a direct smelting reduction furnace according to claim 4, wherein: the fine coal agglomerates at a temperature of 650-850 ℃.
6. The method of manufacturing coal aggregate for a direct smelting reduction furnace according to claim 5, wherein: the fine coal is obtained from a direct iron ore smelting reduction process.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911116224.8A CN110760358A (en) | 2019-11-15 | 2019-11-15 | Method for manufacturing coal aggregate of direct smelting reduction furnace |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911116224.8A CN110760358A (en) | 2019-11-15 | 2019-11-15 | Method for manufacturing coal aggregate of direct smelting reduction furnace |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN110760358A true CN110760358A (en) | 2020-02-07 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201911116224.8A Withdrawn CN110760358A (en) | 2019-11-15 | 2019-11-15 | Method for manufacturing coal aggregate of direct smelting reduction furnace |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110760358A (en) |
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2019
- 2019-11-15 CN CN201911116224.8A patent/CN110760358A/en not_active Withdrawn
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| PB01 | Publication | ||
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| WW01 | Invention patent application withdrawn after publication | ||
| WW01 | Invention patent application withdrawn after publication |
Application publication date: 20200207 |