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Apparatus and method for reduction of coal-based pellets

A pelletizing and coal-based technology, which is applied in the rotary hearth furnace for coal-based pellet reduction and its reduction field, can solve the problems that the metallization rate is difficult to achieve stably, the production efficiency of the rotary hearth furnace is not high, and the heat utilization rate is low. Achieve the effect of furnace temperature control and furnace pressure control stability, increase heating rate and temperature uniformity, and improve metallization rate level

Active Publication Date: 2017-03-08
PANGANG GRP PANZHIHUA STEEL & VANADIUM
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  • Abstract
  • Description
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  • Application Information

AI Technical Summary

Problems solved by technology

The combustion in the hearth of the rotary hearth furnace has two problems: one is that the combustion area is also the reduction area. In order to ensure sufficient combustion and increase the reduction temperature, the entire furnace is inevitably oxidizing or weakly oxidizing. The CO produced is also consumed by combustion, which makes it difficult for the metallization rate to reach more than 80% stably; the second is the occurrence of a large amount of combustion behavior. out of the furnace, which will inevitably lead to serious heat loss
[0006] Therefore, based on the current situation of coal-based pellets into the rotary hearth furnace for reduction of materials and the defects of the reduction process, it is necessary to improve related equipment to solve the problems of low production efficiency, low heat utilization rate and low metallization rate of the rotary hearth furnace

Method used

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  • Apparatus and method for reduction of coal-based pellets

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Effect test

Embodiment 1

[0029] like figure 1 As shown, a device for reducing coal-based pellets includes a gas furnace kiln 1, a gas mixing furnace 2, a high-temperature gas delivery pipeline 4, an air inlet flue 5 and a rotary hearth furnace 6, and the gas furnace kiln 1 The gas mixing furnace 2 is connected to the gas mixing furnace 2 through the high temperature gas delivery pipeline 4, and the gas mixing furnace 2 is connected to the high temperature zone of the rotary hearth furnace 6 through the air inlet flue 5. The reducing gas pipeline 3 is connected. If the gas-fired furnace 1 is not fully burned, that is, the high-temperature flue gas generated by combustion under the condition of insufficient oxygen 2 content ≤ 2%, the reducing gas pipeline 3 can be cancelled. The furnace wall of the rotary hearth furnace 6 can be provided with 0-10 supplementary air outlets; the inner empty height of the hearth of the rotary hearth furnace 6 can be set to 20cm-150cm, and the exhaust gas discharge channe...

Embodiment 2

[0031] A kind of method for the reduction of coal-based pellets of the present invention is as follows, and see figure 1 Shown:

[0032] a. The furnace wall of the rotary hearth furnace 6 is not equipped with a burner device, and 0-10 supplementary air outlets are set. The air flue 5 and the air inlet flue 5 are respectively connected to the high temperature zone of the rotary hearth furnace 6 and the gas mixing furnace 2. The gas mixing furnace 2 is connected to the gas furnace kiln 1 through the high temperature gas delivery pipe 4, and the furnace of the rotary hearth furnace 6 is in production and operation. There is no burning behavior and process inside.

[0033] b. The 0-10 supplementary air outlets set in step a refer to the rotary hearth furnace 6 preheating zone, medium temperature reduction zone and high temperature reduction and cooling zone, or the actual zones that are not clearly divided but correspond to each zone. The above-mentioned several areas or some ar...

Embodiment 3

[0042] With reference to the steps of the above-mentioned embodiment, under the condition that the supplementary air outlet and the reducing gas pipeline 3 are not provided, the gas-fired kiln adopts the combustion of pulverized coal to generate O 2 Volume content 2.8%, (CO+H2) volume content ≤ 1.5%, temperature 1473 ℃ high-temperature flue gas, on the 1t / h design production capacity experimental rotary hearth furnace equipment, the material thickness is 8 layers of balls, and the exhaust gas exhaust rate is 0.5m / s. Compared with the same period of last year, the metallization rate of pellets after reduction before improvement increased by 9% to 88%, the production capacity increased by 0.3t / h to 1.3t / h, and the fuel ratio decreased by 24%.

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Abstract

The invention discloses a device and a method for reducing coal-based pellets, and aims to solve the technical problems of low production capacity caused by the equipment characteristics of a rotary hearth furnace and equipment defect of low metallization ratio after the weak oxidizing atmosphere makes the coal-based pellets be reduced due to the combustion of a hearth region. According to the invention, an original flame thermal radiation heating mode is changed into a flue gas heat exchanging mode by adopting a way that high-temperature flue gas provided by a gas furnace is transferred into the rotary hearth furnace, so that the heating rate and temperature uniformity of the coal-based pellets are improved greatly, and the production capacity can be improved by further increasing the spreading thickness; the hearth region has no combustion behavior and process, so that the atmosphere in the furnace can be always kept as a neutral or weakly reducing atmosphere stably, the metallization ratio level of coal-based pellets is improved greatly, the hearth temperature control and the furnace pressure control are more stable, accurate and easy.

Description

technical field [0001] The invention belongs to the field of metallurgical technology and equipment, and more specifically relates to a rotary hearth furnace for reducing coal-based pellets and a reduction method thereof. Background technique [0002] With the increasing shortage of resources, especially the scarcity of high-quality iron-containing raw materials and coking coal, the survival and development of traditional blast furnace process iron and steel enterprises have been greatly challenged. The non-blast furnace ironmaking technology, which has less resource constraints, greater flexibility, and shorter process, has received more and more attention and attention. In recent years, due to the technological and equipment characteristics of the rotary hearth furnace, it has gradually attracted the attention of the ironmaking industry, and its application in the production of direct reduction of coal-based pellets has achieved rapid development. [0003] The reduction p...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21B13/10C21B13/14
Inventor 刘功国秦洁
Owner PANGANG GRP PANZHIHUA STEEL & VANADIUM