Method for manufacturing metallic pellets by direct reduction of oxygen-enriched combustion in rotary furnace

A technology of metallized pellets and oxygen-enriched combustion, applied in the direction of improving process efficiency, can solve the problems of gas and air consumption, high smoke exhaust, larger equipment specifications, equipment investment costs, high operating costs, etc., to achieve Effects of improving utilization factor, reducing air consumption, and reducing gas consumption

Inactive Publication Date: 2009-06-03
LAIWU IRON & STEEL GRP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this process does not use the oxygen-enriched combustion technology in the first step of the rotary hearth furnace pre-reduction. Compared with the rotary hearth furnace process using the oxygen-enriched combustion technology, the gas and air consumption and smoke emission of this step are lower. Therefore, the corresponding equipment specifications become larger, and the equipment investment cost and operating cost are also higher

Method used

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  • Method for manufacturing metallic pellets by direct reduction of oxygen-enriched combustion in rotary furnace
  • Method for manufacturing metallic pellets by direct reduction of oxygen-enriched combustion in rotary furnace

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] When air is used as the combustion gas, the air enters the heat exchanger through the blower, and after the heat exchange between the air and the high-temperature flue gas, the air temperature rises to 500°C, and then enters the rotary hearth furnace to participate in the combustion reaction. O in gas and air 2 Mixed combustion in the burner, the heat released by the combustion reaction is transferred to the pellets in the form of radiant heat, which is used for the reduction of iron, lead, zinc and other oxides in the pellets. The generated metal zinc, lead, etc. are separated from the pellets and enter the flue gas, and most of the iron oxides inside the pellets are reduced to metallic iron. The metallized pellets produced by direct reduction in the rotary hearth furnace have a grade of more than 65%, a metallization rate of more than 70%, and broken balls and powders less than 5mm not more than 3%, which can be directly used in the blast furnace.

[0032] Based on 1...

Embodiment 2

[0034] Oxygen-enriched combustion direct reduction of rotary hearth furnace equipment for producing metallized pellets, including: rotary hearth furnace, blower, heat exchanger, oxygen delivery pipe, air intake pipe; the oxygen delivery pipe is connected to the air delivery pipe, and the air delivery pipe passes through The blower is connected to the heat exchanger, which is connected to the burner of the rotary hearth furnace through pipes. A valve and a pressure detection gauge are left on the oxygen delivery pipe. The amount of oxygen dispensed is controlled by a valve and a pressure gauge on the oxygen delivery pipe.

[0035] The oxygen delivery pipe is connected to the air delivery pipe, and the amount of oxygen to be distributed is controlled by the valve on the oxygen delivery pipe and the pressure detection gauge. The oxygen-enriched mixed gas enters the heat exchanger for heat exchange and temperature rise by means of the blower. The heat source is the high-temperatu...

Embodiment 3

[0039] When 30% oxygen-enriched gas is used as the supporting gas, air and pure oxygen are mixed in a certain proportion to form oxygen-enriched oxygen, which enters the heat exchanger through the blower, and after heat exchange between the enriched oxygen and high-temperature flue gas, the temperature of the enriched oxygen rises to 600°C , and then enter the rotary hearth furnace to participate in the direct reduction reaction. Others are with embodiment 2. Based on 1 ton of metallized pellets, the gas consumption is 147.82Nm 3 / t, air consumption 728.06Nm 3 / t, pure oxygen consumption 93.61Nm 3 / t, total combustion gas consumption 821.69Nm 3 / t, smoke generation 1136.11Nm 3 / t, the flue gas outlet temperature is 1100°C.

[0040] Implementation case comparison:

[0041]

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Abstract

The invention provides a method for manufacturing metallic pellets by direct reduction of oxygen-enriched combustion in a rotary furnace, which belongs to the technical field of steel industry for manufacturing metallic pellets (or direct reduction iron). The method is characterized in that oxygen enriched air is adopted as an auxiliary fuel gas; the oxygen enriched air enters a heat exchanger through a blower; and after the heat exchange between the oxygen enriched air and high temperature flue gas is performed, the temperature rises to 400 DEG C to 600 DEG C, and then the oxygen enriched air enters the rotary furnace. The invention breaks through the limitation of the prior air taking as a combustion medium and fixing the oxygen content, realizes the actual demand that the oxygen content in the combustion medium is controllable, further enhances the heat efficiency of the rotary furnace, reduces over 35% of air consumption amount, reduces over 31% of total consumption amount of the auxiliary fuel gas; and the coal gas consumption, the flue gas discharge capacity and the investment cost are reduced, and conforms to the national policy requirements of energy conservation, emission reduction and circulation economy.

Description

technical field [0001] The invention belongs to the technical field of metallized pellet (or direct reduced iron) production in the iron and steel industry, and specifically relates to a technology for promoting energy saving and consumption reduction of a rotary hearth furnace system by using preheated oxygen-enriched air. Background technique [0002] The production of metallized pellets (direct reduced iron) by rotary hearth furnace direct reduction process is a new ironmaking process developed in the last thirty years. Because this process does not require the preparation of fuel and the deep processing of raw materials, it has a positive effect on the rational use of natural resources and the protection of the human environment, so it has received widespread attention from the metallurgical industry. [0003] The existing rotary hearth furnace processes at home and abroad all use air as the combustion-supporting medium. Since the content of oxygen in the air is fixed, t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22B1/00
CPCY02P10/20
Inventor 曾晖薛庆国李建云姜泽毅谷卓奇王静松陈锡明周林
Owner LAIWU IRON & STEEL GRP
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