阅读说明：本技术 一种向熔融还原炉内喷吹低温纯氧的方法及装置 (Method and device for blowing low-temperature pure oxygen into smelting reduction furnace ) 是由 孟凡旭 徐涛 张勇 周海川 卜二军 任俊 程鹏 昝智 杨阳 肖嘉诚 于 2021-09-09 设计创作，主要内容包括：本发明公开了一种向熔融还原炉喷吹低温纯氧的方法,氧气站(1)提供的低温纯氧,经氧气调节阀(2)和氧气切断阀(3)经纯氧管道(4)由热风喷枪(5)直接喷入熔融还原炉(12)内,低温纯氧在熔融还原炉内二次燃烧区域(9)呈“伞状”分布；矿粉、煤粉、白云石粉和石灰粉通过喷吹管线(17)经固体喷枪(11)喷入熔融还原炉熔池区。该方法与原工艺相比取消了电动鼓风系统和热风炉系统,大幅度降低了整体工艺的投资建造成本。该方法与原工艺相比大量提高了二次燃烧区的燃烧温度,增强了二次燃烧区与熔池区域的换热效率,直接解决了熔池补热问题。(The invention discloses a method for injecting low-temperature pure oxygen into a melting reduction furnace, wherein the low-temperature pure oxygen provided by an oxygen station (1) is directly injected into the melting reduction furnace (12) through an oxygen regulating valve (2) and an oxygen stop valve (3) and a pure oxygen pipeline (4) by a hot air spray gun (5), and the low-temperature pure oxygen is distributed in an umbrella shape in a secondary combustion area (9) in the melting reduction furnace; the mineral powder, the coal powder, the dolomite powder and the lime powder are injected into a smelting pool area of the smelting reduction furnace through a solid spray gun (11) through an injection pipeline (17). Compared with the prior art, the method cancels an electric blast system and a hot blast stove system, and greatly reduces the investment and construction cost of the whole process. Compared with the prior art, the method greatly improves the combustion temperature of the secondary combustion area, enhances the heat exchange efficiency of the secondary combustion area and a molten pool area, and directly solves the problem of molten pool heat compensation.)

1. A method for blowing low-temperature pure oxygen into a smelting reduction furnace is characterized in that the low-temperature pure oxygen provided by an oxygen station (1) is directly sprayed into the smelting reduction furnace (12) through an oxygen regulating valve (2) and an oxygen stop valve (3) and a pure oxygen pipeline (4) by a hot air spray gun (5), and the low-temperature pure oxygen is distributed in an umbrella shape in a secondary combustion area (9) in the smelting reduction furnace; mineral powder, coal powder, dolomite powder and lime powder are sprayed into a molten pool area of the smelting reduction furnace through a solid spray gun (11) through a spraying pipeline (17); the coal dust in the lower melting pool area is carburized and then reduces the injected iron ore into molten iron, and the molten iron and the slag in the melting pool are gushed into a secondary combustion area (9) in the form of Yongquan by volatile gas separated from the coal dust and CO gas generated by reduction reaction; the coal gas entering the secondary combustion area (9) and the low-temperature pure oxygen generate violent combustion reaction; the iron drops and slag drops entering the secondary combustion zone exchange heat with high-temperature flue gas generated after the coal gas is combusted, and finally the heat is brought back to the molten pool; the residual gas of the smelting reduction furnace is sent to a subsequent gas user (21) through a vaporization cooling flue (10) and a dust removal pressure reducing device (13).

2. The method of injecting low-temperature pure oxygen into a smelting reduction furnace according to claim 1, wherein the lower end of the hot blast lance (5) is a hot blast lance muzzle (6) having a 4-8 hole nozzle.

3. The method of injecting low temperature pure oxygen into a smelting reduction furnace according to claim 2, wherein the distance from the tuyere (6) of the hot blast lance to the hearth (7) of the smelting reduction furnace is reduced to 6.5 to 7.5m, and the distance from the slag hole interface (8) is reduced to 3 to 3.5 m.

4. A method of injecting low temperature pure oxygen into a smelting reduction furnace according to claim 3, wherein the amount of oxygen introduced into the smelting reduction furnace (12) is adjusted by an oxygen adjusting valve (2) at an outlet of an oxygen station, and a pressure gauge I (15) and a flow meter (14) are installed between the oxygen cut-off valve (3) and the hot blast lances to measure the pressure and flow rate of the low temperature pure oxygen introduced into the smelting reduction furnace.

5. The method of injecting low-temperature pure oxygen into a smelting reduction furnace according to claim 4, wherein a pressure gauge II (16) is provided at an inlet of the vaporization cooling flue (10) and a pressure is controlled within a range of 60 to 80 kPa.

6. The method for injecting low-temperature pure oxygen into a smelting reduction furnace as set forth in claim 5, wherein the ratio of the raw materials of iron ore powder to dolomite is 9:1, and both of them are mixed and fed into the injection line (17), wherein the setting value of the injection amount is 100-135t/h, and the amount of dolomite is adjusted according to the ratio.

7. The method of injecting low temperature pure oxygen into a smelting reduction furnace as set forth in claim 6, wherein the temperature of the gas introduced into the flue of the smelting reduction furnace is raised to 200-300 ℃.

8. The method of injecting low-temperature pure oxygen into a smelting reduction furnace according to claim 7, wherein the iron is tapped for 70 to 90t/h and the slag is tapped once every two times.

9. The method of injecting low temperature pure oxygen into a smelting reduction furnace according to claim 8, wherein the ore powder includes Fe (%) > 62.0% or more and SiO [% ]₂(％)：4.2～4.7％，Al₂O₃(%): 2.2%, P (%): 0.08 percent of S, 0.03 percent of S and less than or equal to 5 percent of water (%).

10. An apparatus for carrying out the method for injecting low-temperature pure oxygen into a smelting reduction furnace according to claims 1 to 9.

Technical Field

The embodiment of the disclosure relates to the field of non-blast furnace ironmaking, in particular to a method and a device for blowing low-temperature pure oxygen into a smelting reduction furnace.

Background

At present, an oxygen-enriched hot air technology mainly adopted in an iron making process of a smelting reduction furnace in the world is that a cold air is blown out by an electric blower, the cold air is heated into oxygen-enriched hot air at 1100-1200 ℃ by a hot air furnace after being mixed with oxygen, finally the oxygen-enriched hot air is conveyed by a hot air pipeline and sprayed into the smelting reduction furnace by a hot air spray gun, a secondary combustion area of the oxygen-enriched hot air is formed at a certain position on the upper part of molten iron and a slag layer, the oxygen-enriched hot air enables the sprayed hot air to carry out combustion reaction with CO and H2 gas generated inside a molten pool, the generated heat exchanges heat with rising slag and iron liquid drops of an artesian spring, and the molten pool is continuously supplemented with heat. The prior art has a more complex electric blast system and a hot blast stove system with high construction cost. When oxygen-enriched hot air is sprayed into the smelting reduction furnace in the original process, on one hand, a large amount of nitrogen can be sprayed into the air, and the nitrogen can take away a large amount of heat in the furnace, so that the temperature in the smelting reduction furnace is lower, the heat exchange efficiency with a molten pool is reduced, and energy waste is caused. On the other hand, the gas of the smelting reduction furnace contains a large amount of nitrogen, so that the heat value of the gas of the smelting reduction furnace is lower, the subsequent combustion temperature of the smelting reduction furnace is reduced, the gas power generation is not facilitated, and the tail gas emission does not reach the standard due to the existence of a large amount of nitrogen oxides in the flue gas.

Disclosure of Invention

In order to solve the technical problems and achieve the corresponding technical effects, the invention provides a method for blowing low-temperature pure oxygen into a smelting reduction furnace. Firstly, an electric blowing system and a hot blast stove system in the original process are cancelled, and low-temperature pure oxygen is directly blown into a hot blast spray gun after being blown out from an oxygen station and enters a melting reduction furnace. The low-temperature oxygen-enriched air and the coal dust and combustible gas from the molten pool generate violent combustion reaction in a secondary combustion area. The high-temperature flue gas exchanges heat with the slag and molten iron which rise in the molten pool, and finally more heat is brought back to the molten pool. Meanwhile, the proportion of N2 in the gas of the melting reduction furnace and the heat brought out of the furnace by N2 are reduced, the utilization efficiency of the energy in the furnace is further improved, the heat value of the gas is improved, and the generation of nitrogen oxides of subsequent gas users (21) is reduced.

The basic concept adopted by the invention is as follows:

a method for blowing low-temperature pure oxygen into a smelting reduction furnace is characterized in that low-temperature pure oxygen provided by an oxygen station (1) is directly sprayed into the smelting reduction furnace (12) through an oxygen regulating valve (2) and an oxygen stop valve (3) and a pure oxygen pipeline (4) by a hot air spray gun (5), and the low-temperature pure oxygen is distributed in an umbrella shape in a secondary combustion area (9) in the smelting reduction furnace; mineral powder, coal powder, dolomite powder and lime powder are sprayed into a molten pool area of the smelting reduction furnace through a solid spray gun (11) through a spraying pipeline (17); the coal dust in the lower melting pool area is carburized and then reduces the injected iron ore into molten iron, and the molten iron and the slag in the melting pool are gushed into a secondary combustion area (9) in the form of Yongquan by volatile gas separated from the coal dust and CO gas generated by reduction reaction; the coal gas entering the secondary combustion area (9) and the low-temperature pure oxygen generate violent combustion reaction; the iron drops and slag drops entering the secondary combustion zone exchange heat with high-temperature flue gas generated after the coal gas is combusted, and finally the heat is brought back to the molten pool; the residual gas of the smelting reduction furnace is sent to a subsequent gas user (21) through a vaporization cooling flue (10) and a dust removal pressure reducing device (13).

Furthermore, the lower end of the hot air spray gun (5) is provided with a hot air spray gun with a 4-hole spray head.

Furthermore, the lower end of the hot air spray gun (5) is provided with a hot air spray gun with a 6-hole spray head.

Furthermore, the lower end of the hot air spray gun (5) is provided with a hot air spray gun with an 8-hole spray head.

Furthermore, the lower end of the hot air spray gun (5) is provided with a waist-shaped spray head.

Further, the inner diameter of the hot air spray gun (5) becomes 830mm, and the outer diameter becomes 1230 mm.

Further, the distance between the muzzle (6) of the hot air spray gun and the bottom (7) of the smelting reduction furnace is reduced to 6.5-7.5m, and the distance between the muzzle (6) of the hot air spray gun and the slag hole interface (8) of the smelting reduction furnace is reduced to 3-3.5 m.

Further, the flow rate of the low-temperature pure oxygen blown by the hot air spray gun is 45000-³The pressure is 150-250kPa, the temperature is 0-100 ℃, the normal temperature is 25 ℃, and the pure oxygen content is 98-99.99%.

Furthermore, the amount of oxygen entering the smelting reduction furnace (12) is regulated through an oxygen regulating valve (2) at the outlet of the oxygen station, and a pressure gauge I (15) and a flow meter (14) are arranged between the oxygen stop valve (3) and the hot air spray gun and used for measuring the pressure and the flow of low-temperature pure oxygen entering the smelting reduction furnace.

Further, a pressure gauge II (16) is arranged at the inlet of the vaporization cooling flue (10), and the pressure range is controlled to be 60-80 kPa.

Furthermore, the ratio of the raw materials of the iron ore powder and the dolomite is 9:1, the iron ore powder and the dolomite enter the blowing pipeline (17) in the form of a mixture, wherein the ore blowing amount is set to be 100-.

Further, the temperature of the gas entering the flue of the smelting reduction furnace is increased to 200-300 ℃.

Further, tapping 70-90t/h, and tapping once after tapping twice.

Further, the ore powder comprises Fe (%) > 62.0% and SiO₂(％)：4.2～4.7％，Al₂O₃(%): 2.2%, P (%): 0.08 percent of S, 0.03 percent of S and less than or equal to 5 percent of water (%).

Further, an apparatus for carrying out the above method for injecting low-temperature pure oxygen into a smelting reduction furnace.

Compared with the prior art, the invention has the following advantages:

the invention aims to provide a method for blowing low-temperature oxygen-enriched air into a smelting reduction furnace. Compared with the prior art, the method omits an electric blast system and a hot blast furnace system, shortens the process steps, and greatly reduces the whole processInvestment and construction costs of the bulk process. Compared with the prior art, the method greatly improves the combustion temperature of the secondary combustion area, enhances the heat exchange efficiency of the secondary combustion area and a molten pool area, and directly solves the problem of molten pool heat compensation. Compared with the prior art, the method greatly reduces N in the gas of the smelting reduction furnace₂The heat out of the furnace is taken, the utilization efficiency of the energy in the furnace is improved, and the heat value of the coal gas is further improved. Meanwhile, the generation of nitrogen oxides of subsequent gas users (21) is reduced, and the effect of protecting the environment is achieved.

It should be understood that the statements herein reciting aspects are not intended to limit the critical or essential features of the embodiments of the present disclosure, nor are they intended to limit the scope of the present disclosure. Other features of the present disclosure will become apparent from the following description.

Drawings

The above and other features, advantages and aspects of various embodiments of the present disclosure will become more apparent by referring to the following detailed description when taken in conjunction with the accompanying drawings. In the drawings, like or similar reference characters designate like or similar elements, and wherein:

FIG. 1 is a schematic view of an apparatus for injecting low-temperature pure oxygen into a smelting reduction furnace according to the method of the present invention.

FIG. 2 is a schematic view of a 4-hole nozzle of a hot air spray gun head according to the method of the present invention.

FIG. 3 is a schematic view of a 6-hole nozzle of a hot air spray gun according to the method of the present invention.

FIG. 4 is a schematic view of a 8-hole nozzle of a hot air spray gun according to the method of the present invention.

FIG. 5 is a schematic view of a waist-shaped nozzle of a hot air spray gun according to the method of the present invention.

1-an oxygen station; 2-an oxygen regulating valve; 3-oxygen cut-off valve; 4-a pure oxygen pipeline; 5-hot air spray gun, 6-hot air spray gun muzzle, 7-smelting reduction furnace bottom, 8-slag hole interface; 9-a secondary combustion zone; 10-a vaporization cooling flue; 11-a solids lance; 12-a smelting reduction furnace; 13-dust removal and pressure reduction equipment; 14-a flow meter; 15-pressure gauge I; 16-pressure gauge II; 17-a blowing line; 18-mineral powder and dolomite; 19-pulverized coal; 20-lime; 21-gas user (21).

Detailed Description

To make the objects, technical solutions and advantages of the embodiments of the present disclosure more clear, the technical solutions of the embodiments of the present disclosure will be described clearly and completely with reference to the drawings in the embodiments of the present disclosure, and it is obvious that the described embodiments are some, but not all embodiments of the present disclosure. All other embodiments, which can be derived by a person skilled in the art from the embodiments disclosed herein without making any creative effort, shall fall within the protection scope of the present disclosure.

Example 1

As shown in FIG. 2, in example 1 of the present invention, low-temperature pure oxygen supplied from an oxygen station (1) is directly injected into a smelting reduction furnace (12) through an oxygen regulating valve (2) and an oxygen shut-off valve (3) via a pure oxygen pipe (4) by a hot air lance (5). The low-temperature pure oxygen is distributed in an umbrella shape in a secondary combustion area (9) in the melting reduction furnace. The mineral powder, the coal powder, the dolomite powder and the lime powder are injected into a smelting pool area of the smelting reduction furnace through a solid spray gun (11) through an injection pipeline (17). The coal dust in the lower melting pool area is carburized and then reduces the injected iron ore into molten iron, and the molten iron and the slag in the melting pool are gushed into a secondary combustion area (9) in the form of Yongquan by volatile gas separated from the coal dust and CO gas generated by reduction reaction. The coal gas entering the secondary combustion area (9) and the low-temperature pure oxygen generate violent combustion reaction. The iron drops and slag drops entering the secondary combustion area exchange heat with high-temperature flue gas generated after the coal gas is combusted, and finally the heat is brought back to the molten pool. The residual gas of the smelting reduction furnace is sent to a subsequent gas user (21) through a vaporization cooling flue (10) and a dust removal pressure reducing device (13).

Compared with the prior art, the process for blowing the low-temperature pure oxygen into the smelting reduction furnace has the advantages that the combination of the outer sleeve and the rotational flow guide rod of the prior art is changed into the oxygen spray gun with the 4-8-hole spray head by the hot air spray gun (5).

Compared with the prior art, the process for blowing the low-temperature pure oxygen into the smelting reduction furnace has the advantages that the distance between the muzzle (6) of the hot air spray gun and the bottom (7) of the smelting reduction furnace is reduced to 6.5-7.5m, and the distance between the muzzle (6) of the hot air spray gun and the slag hole interface (8) of the smelting reduction furnace is reduced to 3-3.5 m.

The method of the invention adjusts the amount of oxygen entering the smelting reduction furnace (12) through an oxygen adjusting valve (2) at the outlet of the oxygen station.

A pressure gauge 1(15) and a flow meter 1(14) are arranged between the oxygen shut-off valve (3) and the hot air spray gun and are used for measuring the pressure and the flow of the low-temperature pure oxygen entering the melting reduction furnace.

Furthermore, compared with the prior art, the process for blowing the low-temperature pure oxygen into the smelting reduction furnace eliminates two groups of large-scale equipment, namely an electric blower and a hot blast stove.

According to the process for blowing the low-temperature pure oxygen into the smelting reduction furnace, a pressure gauge 2(16) is arranged at an inlet of a vaporization cooling flue, and the pressure range is controlled to be 60-80 kPa.

The ratio of raw materials, namely iron ore powder and dolomite, used in the process of blowing the low-temperature pure oxygen into the smelting reduction furnace is 9:1, and the iron ore powder and the dolomite enter a blowing pipeline (17) in a mixed material form. Wherein the ore spraying amount set value is 100-135t/h, and the dolomite amount is adjusted along with the ore spraying amount according to the proportion.

Further, the components of the blowing ore powder in the method of the present invention are shown in Table 1,

TABLE 1 ingredient list of iron ore powder

Composition (I)

Fe(％)

SiO2(％)

Al2O3(％)

P(％)

S(％)

Water (%)

+6.3mm(％)

Index (I)

≥62.0

4.2～4.7

2.2

0.08

0.03

≤5

≤12.0

The dolomite composition of the process of the invention is shown in table 2,

TABLE 2 Dolomite ingredient Table

Name (R)	MgO	SiO2	Acid insoluble substance	Moisture content
					Index (I)	≥19％	≤4％	≤7％	3～5％

The raw material coal powder used by the process of blowing low-temperature pure oxygen into the smelting reduction furnace is anthracite, the specific components are shown in Table 3,

TABLE 3 pulverized coal ingredient Table

The raw material lime powder used in the process of blowing low-temperature pure oxygen into the smelting reduction furnace in the method has the specific components shown in Table 4,

TABLE 4 lime powder ingredient table

Compared with the prior art, the process for blowing the low-temperature pure oxygen into the melting reduction furnace has the advantages that the combustion temperature of the secondary combustion area is increased to 400-600 ℃.

Compared with the prior art, the process for blowing the low-temperature pure oxygen into the smelting reduction furnace has the advantages that the temperature of the coal gas entering the flue of the smelting reduction furnace is increased to 200-300 ℃.

The method of the invention discharges iron 70-90t/h by blowing low-temperature pure oxygen into the smelting reduction furnace, and slag is discharged once after every two times of iron discharge.

Example 2

Compared with the prior art, the method for blowing the low-temperature pure oxygen into the smelting reduction furnace, which is disclosed by the embodiment 2 of the invention, has the advantage that the secondary combustion rate in the smelting reduction furnace is improved by 1.5%. The secondary combustion rate in the melting reduction furnace of the prior process is controlled to be 55 percent, and the secondary combustion rate in the melting reduction furnace of the method is controlled to be 56 percent.

Blowing mineral powder into a smelting reduction furnace for 135t/h in the original process; blowing coal powder at 71.76 t/h; the air quantity of the oxygen-enriched hot air is 146900Nm³H, the oxygen enrichment rate is 38 percent, and the hot air temperature is 1100 ℃; the post combustion rate was controlled to 55%. The casting of iron is realized at 80t/h,the combustion temperature in the furnace was 2982 ℃ yielding 213500Nm³The calorific value of the gas per hour of the smelting reduction furnace is 624 kcal.

The method of the invention blows 135t/h of mineral powder into the smelting reduction furnace; injecting coal powder for 72 t/h; blowing 55800Nm3/h of low-temperature pure oxygen; the post combustion rate was controlled to 56%. Realizes 80t/h of iron tapping, has the combustion temperature in the furnace of 3622 ℃, generates 124400Nm3/h of melting reducing furnace gas, and has the gas heat value of 1052 kcal.

In conclusion, compared with the prior art, the method for blowing the low-temperature pure oxygen into the smelting reduction furnace has the advantages that the ore injection is unchanged, the coal injection is improved by 0.04t/h, and the secondary combustion rate is improved by 1.5%. The heat balance of the process can be met, the iron yield is ensured to be 80t/h, and the coal gas calorific value of the smelting reduction furnace is improved to 428 kcal.

Example 3

Compared with the prior art, the method for blowing the low-temperature pure oxygen into the smelting reduction furnace in the embodiment 3 of the invention keeps the post combustion rate in the smelting reduction furnace unchanged, and the post combustion rate is controlled to be 55%.

Blowing mineral powder into a smelting reduction furnace for 135t/h in the original process; blowing coal powder at 71.76 t/h; the air quantity of the oxygen-enriched hot air is 146900Nm³H, the oxygen enrichment rate is 38 percent, and the hot air temperature is 1100 ℃; the post combustion rate was controlled to 55%. Realizes 80t/h of tapping, the combustion temperature in the furnace is 2982 ℃, and 213500Nm is generated³The calorific value of the gas per hour of the smelting reduction furnace is 624 kcal.

The method of the invention blows 135t/h of mineral powder into the smelting reduction furnace; blowing coal powder at 73.2 t/h; blowing 57200Nm3/h of low-temperature pure oxygen; the post combustion rate was controlled to 55%. The tapping of 80t/h is realized, the combustion temperature in the furnace is 3587 ℃, 124400Nm3/h molten reducing furnace gas is generated, and the calorific value of the gas is 1091 kcal.

In conclusion, compared with the prior art, the method for blowing the low-temperature pure oxygen into the smelting reduction furnace has the advantages that the ore injection is unchanged, the secondary combustion rate is unchanged, and the coal injection is improved by 1.24 t/h. The heat balance of the process can be met, the iron yield is ensured to be 80t/h, and the calorific value of the coal gas of the smelting reduction furnace is increased by 467 kcal.

Example 4

Compared with the prior art, the method for blowing the low-temperature pure oxygen into the smelting reduction furnace in the embodiment 3 of the invention keeps the calorific value of the coal gas of the smelting reduction furnace unchanged, and the calorific value of the coal gas is 624 kcal.

Blowing mineral powder into a smelting reduction furnace for 135t/h in the original process; blowing coal powder at 71.76 t/h; the amount of blown oxygen-enriched hot air is 146900Nm3/h, the oxygen enrichment rate is 38 percent, and the temperature of the hot air is 1100 ℃; controlling the secondary combustion rate to be 55%; the calorific value of the coal gas is controlled to be 624 kcal. Realizes tapping at 80t/h, the combustion temperature in the furnace is 2982 ℃, and 213500Nm3/h molten reducing furnace gas is generated.

The method of the invention blows 135t/h of mineral powder into the smelting reduction furnace; blowing 60.24t/h of coal powder; blowing 49300Nm3/h of low-temperature pure oxygen; controlling the secondary combustion rate to be 73.5 percent; the calorific value of the coal gas is controlled to be 624 kcal. The tapping of 80t/h is realized, the combustion temperature in the furnace is 3982 ℃, and 103200Nm3/h molten reducing furnace gas is generated.

In conclusion, compared with the prior art, the method for blowing the low-temperature pure oxygen into the smelting reduction furnace has the advantages that the ore spraying is unchanged, and the heat value of the gas of the smelting reduction furnace is unchanged. The heat balance of the process can be met, the iron yield is ensured to be 80t/h, and the injected coal powder is reduced by 11.6 t/h.

In the description of the present application, the description of the terms "one embodiment," "some embodiments," etc. means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.