CN1502705A

CN1502705A - Method for self-heatnig fusion reduction of carbon containing pellet

Info

Publication number: CN1502705A
Application number: CNA021446296A
Authority: CN
Inventors: 琦汪; 汪琦; 李文忠
Original assignee: Anshan University of Science and Technology
Current assignee: Anshan University of Science and Technology
Priority date: 2002-11-27
Filing date: 2002-11-27
Publication date: 2004-06-09
Anticipated expiration: 2022-11-27
Also published as: CN1227370C

Abstract

The present invention discloses a method for natural melt-reduction of carbon-containing pellet. Said method is characterized by that the cold-consolidated carbon-containing pellet can be used as raw material, and its reaction equipment is a vertical furnace whose upper portion can be used for making pre-reduction and lower portion can be used for making iron bath final reduction.

Description

Carbonaceous pelletizing is from the method for hot melting reduction

Technical field the present invention relates to a kind of method of producing liquid molten iron, especially is furnace charge with the carbonaceous pelletizing, and shaft furnace is the method for the liquid molten iron of production of reaction unit.

Background technology is that the melting reduction method of raw material is a two step method at present with the carbonaceous pelletizing, and the first step is prereduction, and second step was whole reduction.The prereduction reactor has rotary hearth furnace (Fastmelt method) and shaft furnace, and whole reduction reactor generally adopts the iron bath type reactor.

" iron and steel " supplementary issue (2000, introduced " producing the Fastmet and the Fastmelt novel process process of DRI and molten iron " in Vol.35).The Fastmelt method be will produce that the Fastmet method of direct-reduced iron (DIR) combines with electric smelting furnace (EIF) two go on foot smelting reduction process.Carbonaceous pelletizing reaches 80%～90% degree of metalization through Fastmet method reduction, and hot charging is gone into to carry out in the EIF to reduce end and separated with slag iron then.The Fastmet method be will burn the high temperature that produces of flame pass to the pelletizing on bed of material surface by radiation through the furnace wall, the part heat reaches the place on 1～2 layer on surface by the hole radiating capacity of the bed of material, this makes the Fastmet method can only spread 2～3 layers of pelletizing on furnace bottom, thickness is 20～30mm, though reduction rate is very fast, the residence time has only 9～11min, but production efficiency is lower.

In the shaft furnace preliminary reduction process, " carbonaceous pelletizing shaft furnace melting reduction iron-smelting method " arranged, number of patent application: 85100843.The shortcoming of this method is hot blast or the cold wind that 2～3 exhaust outlets making in the shaft furnace bottom directly blast, and the pelletizing after the reduction is reoxidized.Also has " carbonaceous pelletizing-molten iron bath reduction ironmaking method " number of patent application: 93114553.8; " a kind of device and method of reduction iron-smelting for cold-coagulated carboniferous briquet ", number of patent application: 94107925.2; " carbonaceous pelletizing coal gas circulation melting and reducing flow process ", the patent No.: 96119847.8.The common feature of these methods is: adopt two step smelting reduction process, carbonaceous pelletizing is carried out prereduction in shaft furnace, carry out separating of reduction eventually and slag iron in iron liquid furnace.Their shortcoming is:

1) with high-temperature flue gas of discharging in the whole reduction reactor or the carbonaceous pelletizing in the week reduction gas heating shaft furnace, carry out prereduction, the chemical energy of the inflammable gas that reduction process produces does not obtain utilizing in reactor, and exhaust gas volumn increases with the increase of reduction degree;

2) volatile matter in the coal does not discharge out of the furnace with coal gas through burning, and wherein obnoxious flavour can pollute environment, and coal tar may deposit in gas line in addition, possibility blocking pipe when serious;

3) discharging of furnace charge between two reactors, the limits of coal gas making full use of of coal gas physics heat, method of attachment also is a technical barrier.

At document " Iron and Steel " (1997, (8), the Tecnored method of introducing 39-43) becomes a reactor with reduction shaft furnace " seat " on whole reducing and smelting furnace, be called the improvement shaft furnace, carbonaceous pelletizing is full of whole shaft furnace and directly and be sitting in the shaft furnace bottom, and whole reductive coal gas enters the top of shaft furnace after secondary combustion, adverse current heating carbonaceous pelletizing, pelletizing after the prereduction directly enters the bottom of shaft furnace, carries out the reduction at end and separates with slag iron.This method is combined into a fusion reduction reaction device with prereduction reactor and whole reduction reactor, has only solved connectivity problems such as furnace charge discharging between two reactors, coal gas conversion in the two step smelting reduction process.

The patent " method of iron-bath molten reduction " of nineteen ninety-five application, the patent No.: 95110139.0.This method be with and the stream shaft furnace make the prereduction reactor, bathe to make two of reduction eventually and fecal iron separator with iron and go on foot smelting reduction process.Carbonaceous pelletizing and flow and carry out self-heating reduction in the shaft furnace, both carbonaceous pelletizing and high-temperature oxygen-enriched air added in the stove from the shaft furnace furnace roof, they and flow down in the process of falling, the inflammable gas that the pelletizing reduction process of directly burning produces (CO that fugitive constituent and reduction produce), the reduction heat dissipation is provided, will through and the carbonaceous pelletizing that flows shaft furnace prereduction enter iron and carry out reducing end in bathing and separate with slag iron.This method still exists the prereduction reactor to be connected the problem of difficulty with whole reduction reactor.Double-deck removal device is set, complex structure in the shaft furnace that adopts.

The production efficiency that summary of the invention the present invention is directed to existing two steps smelting reduction process existence is lower; The prereduction reactor is connected difficulty with whole reduction reactor; The shaft furnace complex structure; The chemical energy utilization ratio of inflammable gas is low; The obnoxious flavour pollution on the environment; The easy blockage problem of gas line has proposed improvement project.

Technical scheme of the present invention comprises following content:

With the cold-bonded carbonic pellet is raw material, and reaction unit is that the shaft furnace that iron bath end reducing is carried out in prereduction, bottom is carried out on a top.

Carbonaceous pelletizing is imported from the shaft furnace top with 1100～1200 ℃ that come out through interchanger, the high-temperature oxygen-enriched air of oxygen content＞21%, they are on shaft furnace top and flow down in the process of falling, provide the reduction heat dissipation by the inflammable gas that produces in the direct burning pelletizing reduction process, carry out prereduction, prereduction time 10～20min, prereduction degree＞60～80%.Pelletizing after the prereduction drops to the shaft furnace bottom, at this moment, is blown into oxygen in the shaft furnace bottom, reignition prereduction coal gas of high temperature that produce, that enter the shaft furnace bottom, reduction and the isolating heat dissipation of slag iron eventually are provided, finish to reduce eventually and separate with slag iron, slag iron is discharged from the shaft furnace bottom.The high-temp waste gas of discharging from the shaft furnace bottom is discharged after fly-ash separator dedusting, interchanger heat exchange.

The present invention compared with the prior art, the beneficial effect of generation is:

1) prereduction is dwindled prereduction equipment significantly fast;

2) higher prereduction degree can alleviate reduction load eventually, cuts down the consumption of energy, and alleviates the problems such as erosion of high FeO slag to refractory materials;

3) the shaft furnace reactor of Cai Yonging not only has the advantage of two step smelting reduction process, has also avoided discharging furnace charge, conversion coal gas etc. in the two step smelting reduction process between two reactors;

4) inflammable gas of reduction generation can directly utilize the thermo-efficiency height in reactor;

5) hydrocarbon polymer in the coal can reduce environmental pollution in the reactor internal combustion.

Description of drawings Fig. 1 is technical process and the device sketch of carbonaceous pelletizing from hot melting reduction.

Embodiment is produced cold-bonded carbonic pellet with mill coal as the energy and reductive agent, the requirement that the intensity of carbonaceous pelletizing should satisfy transportation and move in shaft furnace.The selection of coal and blending ratio should satisfy its requirement as the energy and reductive agent in the carbonaceous pelletizing.

As shown in Figure 1, carbonaceous pelletizing 1 and high-temperature oxygen-enriched air 15 are imported shaft furnaces from the charging tube 2 and the gas entrance 16 at shaft furnace top respectively.1100～1200 ℃ of high-temperature oxygen-enriched air themperature, oxygen content＞21%.They are on shaft furnace top 3 and flow down in the process of falling, and carbonaceous pelletizing is earlier by high-temperature oxygen-enriched air heating, and the ferric oxide in the carbonaceous pelletizing begins reduction, provides the reduction heat dissipation by the inflammable gas that produces in the direct burning pelletizing reduction process then, carries out prereduction.Pre-reduced pellet drops to shaft furnace bottom 4, at this moment, is blown into oxygen 5 in the shaft furnace bottom by oxygen blast mouth 6, the coal gas of high temperature that enters shaft furnace bottom 4 that reignition prereduction produces, provide to reduce eventually and separate heat dissipation with slag iron, finish to reduce eventually and separate with slag iron, slag iron 7 is discharged from the iron mouth 8 of slagging tap.

High-temp waste gas 10 from shaft furnace bottom high-temp waste gas outlet 9 is discharged through fly-ash separator 11 dedustings, interchanger 12 heat exchange cooling, becomes low temperature waste gas 13 backs and discharges.

Oxygen-rich air 14 is heated as high-temperature oxygen-enriched air 15 through interchanger 12, blasts shaft furnace from the gas entrance 16 at shaft furnace top.

Claims

1, a kind of carbonaceous pelletizing is characterized in that from the method for hot melting reduction this method comprises following content:

With the cold-bonded carbonic pellet is raw material, and reaction unit is that the shaft furnace that iron bath end reducing is carried out in prereduction, bottom is carried out on a top;

Carbonaceous pelletizing with 1100～1200 ℃ that come out through interchanger, the high-temperature oxygen-enriched air of oxygen content＞21% is imported from the shaft furnace top, they are on shaft furnace top and flow down in the process of falling, provide the reduction heat dissipation by the inflammable gas that produces in the direct burning pelletizing reduction process, carry out prereduction, prereduction time 10～20min, prereduction degree＞60～80%, pelletizing after the prereduction drops to the shaft furnace bottom, at this moment, be blown into oxygen in the shaft furnace bottom, reignition prereduction produces, enter the coal gas of high temperature of shaft furnace bottom, reduction and the isolating heat dissipation of slag iron eventually are provided, finish to reduce eventually and separate with slag iron, slag iron is discharged from the shaft furnace bottom, the high-temp waste gas of discharging from the shaft furnace bottom is through the fly-ash separator dedusting, discharge after the interchanger heat exchange.