CN117431352A - A steel smelting system and method based on hydrogen-rich reducing gas injection - Google Patents

Abstract

The invention discloses a steel smelting system and method based on the injection of hydrogen-rich reducing gas, which includes a blast furnace and a hydrogen-rich reducing gas pre-furnace; the blast furnace is injected with hydrogen-rich reducing gas from the hydrogen-rich reducing gas pre-furnace. and pure hydrogen; the generated blast furnace top gas is introduced into a hydrogen-rich reducing gas prefabricated furnace for decarbonization; the hydrogen-rich reducing gas prefabricated furnace includes coke, biomass pellets and waste plastic pellets, while dry coal powder and pure Oxygen is also injected into the hydrogen-rich reducing gas preheating furnace to prepare hydrogen-rich reducing gas.

Description

A steel smelting system and method based on hydrogen-rich reducing gas injection

Technical field

The present invention relates to steel smelting, and in particular to a steel smelting system and method based on hydrogen-rich reducing gas injection.

Background technique

At present, the main fuel, skeleton and reducing agent for blast furnace smelting molten iron is coke. Coke is obtained by carbonization of coal in coking plants at high temperatures of about 1000°C. The coking process will produce a large amount of harmful chemical pollutants, and the cost is high. In order to ensure the permeability of the blast furnace, the broken coke and coke produced during the coking process generally cannot enter the blast furnace directly.

Reducing blast furnace coke ratio is the key to blast furnace energy saving. In traditional blast furnace smelting, coke is partially replaced by injecting low pulverized coal into the blast furnace. However, large amounts of coal injection will bring a series of adverse effects to blast furnace smelting. For example, pulverized coal will undergo a series of physical and chemical changes such as heating, decomposition, combustion, and slagging inside the blast furnace, making the reaction in the whirling zone complex and difficult to operate. As the amount of coal injection increases, the soft melt zone expands and the coke is seriously damaged. As a result, coal injection is restricted by coke quality; the increase in unburned pulverized coal will further deteriorate the working conditions of the blast furnace's soft melt zone and slag forming zone; and large oxygen-rich coal injection will also cause the blast furnace to become "cold at the top and hot at the bottom."

In addition, blast furnace smelting will produce blast furnace top gas. Blast furnace gas contains CO and CO ₂ . In order to recover the CO in the blast furnace gas, the blast furnace gas will be injected back into the blast furnace. Before that, the CO ₂ in the blast furnace gas needs to be removed, which is also a problem.

Hydrogen has the advantages of being green and renewable, highly reducible, and clean and pollution-free. Hydrogen is widely used instead of carbon as fuel and reducing agent in metallurgical processes, and the reaction product is water. Compared with traditional carbon metallurgy, carbon emissions can be fundamentally reduced and the goal of clean production can be achieved.

Compared with coal, the H ₂ /CO ratio in waste plastic gasification products is much greater than the ratio when pulverized coal is injected, which is more conducive to high-temperature reduction of iron oxides. However, direct injection of plastics in blast furnaces is still in the research stage.

Biomass pellets, another clean renewable energy source, have high calorific value and the characteristics of "carbon cycle and carbon neutrality". After being injected into the blast furnace, it can not only make up for the heat loss in the lower part of the blast furnace caused by hydrogen, but also save coal resources, reduce the possibility of unburned pulverized coal affecting the permeability of the blast furnace, and will not produce excess carbon emissions. However, existing traditional tuyere cannot achieve mixed injection of gas and biomass particles.

Contents of the invention

In view of the above defects of the prior art, the present invention provides a steel smelting system based on the injection of hydrogen-rich reducing gas, including a blast furnace and a hydrogen-rich reducing gas prefabricated furnace; the blast furnace is injected with hydrogen-rich reducing gas from the prefabricated furnace. The hydrogen-rich reducing gas and pure hydrogen of the furnace are recycled; the generated blast furnace top gas is circulated into the hydrogen-rich reducing gas prefabricated furnace for decarbonization; the material column in the hydrogen-rich reducing gas prefabricated furnace includes coke, biomass particles and Waste plastic particles, dry coal powder and pure oxygen are also injected into the hydrogen-rich reducing gas prefabricated furnace to prepare hydrogen-rich reducing gas.

Further, the blast furnace includes an iron-making blast furnace, a cast iron blast furnace, and a ferroalloy blast furnace.

Further, the dry coal powder is hydrogen-rich coal powder.

Furthermore, pure hydrogen is green electricity produced through blast furnace, converter gas power generation and photovoltaic, wind power, nuclear energy, hydropower and grid off-peak power. It is produced through electrolysis of water, or through heavy hydrogen-rich gases such as coke oven gas and natural gas. Prepared after purification.

Furthermore, the molten iron produced by the blast furnace is supplied to primary steel-making furnaces including converters and electric arc furnaces to produce carbon structural steel, alloy structural steel, low-alloy high-strength structural steel, carbon tool steel, and alloy tool steel. , high-speed tool steel, high-carbon steel castings, high-carbon iron castings and stainless steel, and special-purpose steels added with specific alloying elements including rare earths; the special-purpose steels include marine corrosion-resistant steels; and rolled from the above steels Profiles, plates, tubes, rods and wires made from.

Further, a double-cylinder spiral distributor is used at the feed inlet of the hydrogen-rich reducing gas prefabricated furnace, including an outer cylinder; the upper part of the outer cylinder is a spiral feed channel, and the lower part is an inner cylinder; the inner cylinder is It extends below the outer cylinder, and the length of the inner cylinder is set so that the outlet is submerged in the material column in the hydrogen-rich reducing gas prefabricated furnace. The portion of the inner cylinder extending beyond the outer cylinder is provided with multiple pressure equalizing holes. , so that the pressure in the inner cylinder and the furnace is balanced.

The invention also provides a steel smelting method based on hydrogen-rich reducing gas injection, which includes the steps:

(1) Add coke, biomass particles and waste plastic particles into the hydrogen-rich reducing gas prefabricated furnace, spray dry coal powder and pure oxygen at the same time, and burn to prepare hydrogen-rich reducing gas;

(2) Mix the hydrogen-rich reducing gas and pure hydrogen from the hydrogen-rich reducing gas prefabricated furnace and then inject it into the blast furnace;

(3) Introduce the generated blast furnace top gas into a hydrogen-rich reducing gas prefabricated furnace for decarbonization;

(4) Inject pure oxygen into the blast furnace at the same time;

(5) Supply the molten iron produced by the blast furnace to primary steelmaking furnaces including converters and electric arc furnaces to produce carbon structural steel, alloy structural steel, low alloy high-strength structural steel, carbon tool steel, and alloy tool steel , high-speed tool steel, high-carbon steel castings, high-carbon iron castings and stainless steel.

Further, the dry coal powder is hydrogen-rich coal powder.

Furthermore, pure hydrogen is green electricity produced through blast furnace, converter gas power generation and photovoltaic, wind power, nuclear energy, hydropower and grid off-peak power. It is produced through electrolysis of water, or through heavy hydrogen-rich gases such as coke oven gas and natural gas. Prepared after purification.

Further, a double-cylinder spiral distributor is used at the feed inlet of the hydrogen-rich reducing gas prefabricated furnace, including an outer cylinder; the upper part of the outer cylinder is a spiral feed channel, and the lower part is an inner cylinder; the inner cylinder Extends downward below the outer cylinder, and the length of the inner cylinder is set so that the outlet is submerged in the material column in the hydrogen-rich reducing gas prefabricated furnace. At the same time, the portion of the inner cylinder extending beyond the outer cylinder is provided with multiple uniform holes. Press holes to equalize the pressure in the inner cylinder and the furnace; the mixture of coke, biomass particles and waste plastic particles enters the spiral feed channel from above, and in the process of falling along the spiral feed channel, due to the The density is high, so under the action of inertia, its movement trajectory is closer to the outer cylinder, while the density of biomass particles and waste plastic particles is small, and its movement trajectory is closer to the inner cylinder; in this way, after passing through the spiral feed channel, most of the coke particles From entering the furnace through the shorter outer cylinder, they participate in the reactions in the furnace earlier, so that most of the biomass particles and waste plastic particles enter the furnace through the longer inner cylinder, and participate in the reactions in the furnace later.

The invention adopts a hydrogen-rich reducing gas prefabrication furnace, which can prefabricate resources such as pulverized coal, coke, biomass particles and waste plastic particles that are not suitable for directly entering the blast furnace but are beneficial to reducing the energy consumption of the blast furnace into hydrogen-rich reducing gas. , which can then be injected into the blast furnace together with hydrogen. Among them, prefabricating pulverized coal into hydrogen-rich reducing gas can eliminate the adverse effects of coal injection on blast furnace conditions; prefabricating coke, biomass particles and waste plastic particles into hydrogen-rich reducing gas can fully utilize resources. Application and recycling. By introducing the blast furnace gas into the hydrogen-rich reducing gas prefabricated furnace, the decarbonization of the blast furnace gas can be easily achieved. More importantly, through the comprehensive processing of the above-mentioned various resources by the hydrogen-rich reducing gas prefabricated furnace, the unified conversion into hydrogen-rich reducing gas can be realized according to the hydrogen-rich reducing gas during the subsequent mixed injection with pure hydrogen. As the composition changes, the control system dynamically adjusts the ratio of CO and H ₂ to achieve control of the reducing atmosphere and heat of the blast furnace, thereby enabling replaceable control of the furnace ore. In summary, through the unified recovery, conversion and utilization of resources, the present invention reduces blast furnace energy consumption, thereby reducing carbon emissions from steel smelting. The invention also provides a double-cylinder spiral distributor, which can make the consumption speed of biomass particles and waste plastic particles that burn faster and coke that burns slower converge. In this way, during the preproduction process of hydrogen-rich reducing gas, the distribution of raw materials in the furnace material column can be more uniform, and the temperature in the furnace can be more balanced.

The concept, specific structure and technical effects of the present invention will be further described below in conjunction with the accompanying drawings to fully understand the purpose, features and effects of the present invention.

Description of the drawings

Figure 1 is a schematic diagram of a steel smelting system based on hydrogen-rich reducing gas injection in a preferred embodiment of the present invention;

Figure 2 is a schematic diagram of a hydrogen-rich reducing gas prefabricated furnace in a preferred embodiment of the present invention;

Figure 3 is a schematic diagram of a double-tube spiral distributor in a preferred embodiment of the present invention;

FIG. 4 is a schematic diagram of a hydrogen-rich reducing gas prefabricated furnace using the double-cylinder spiral distributor in FIG. 3 .

Detailed ways

The following describes multiple preferred embodiments of the present invention with reference to the accompanying drawings to make the technical content clearer and easier to understand. The present invention can be embodied in many different forms of embodiments, and the protection scope of the present invention is not limited to the embodiments mentioned herein.

A steel smelting system based on hydrogen-rich reducing gas injection in a preferred embodiment of the present invention is shown in Figure 1 and includes a blast furnace 2 and a hydrogen-rich reducing gas prefabricated furnace 1. The hydrogen-rich reducing gas from the hydrogen-rich reducing gas prefabricated furnace 1, hydrogen gas obtained by green electrolysis, and pure oxygen are injected into the blast furnace 2 to perform molten iron smelting. Then the molten iron produced in blast furnace 2 enters the steelmaking process and is supplied to primary steelmaking furnaces such as converters and electric arc furnaces to produce carbon structural steel, alloy structural steel, low alloy high strength structural steel, carbon tool steel, and alloy tool steel. , high-speed tool steel, high-carbon steel castings, high-carbon iron castings and stainless steel.

To pre-produce the hydrogen-rich reducing gas, add coke, biomass particles and waste plastic particles from the top of the hydrogen-rich reducing gas pre-furnace 1, and spray dry coal powder from the furnace body of the hydrogen-rich reducing gas pre-furnace 1 and industrial pure oxygen, and at the same time, the blast furnace gas of the blast furnace 2 is also introduced into the hydrogen-rich reducing gas prefabricated furnace 2. The dry coal powder is preferably hydrogen-rich coal powder.

The hydrogen-rich reducing gas prefabricated furnace 1 in a preferred embodiment of the present invention is shown in Figure 2. The lower part of the furnace body is made of ash 13, and the middle part is made of coke 11 and biomass particles and waste plastic particles 12. Powdered coal and industrial pure oxygen are fed into the combustion chamber to generate hydrogen-rich reducing gases such as CO and H ₂ , which are discharged from the upper part of the furnace body of the hydrogen-rich reducing gas prefabricated furnace 1 and injected into the blast furnace 2.

The CO ₂ in the blast furnace gas introduced into the hydrogen-rich reducing gas prefabricated furnace 1 reacts with the coke in the furnace and is reduced to CO.

The invention adopts a hydrogen-rich reducing gas prefabrication furnace, which can prefabricate resources such as pulverized coal, coke, biomass particles and waste plastic particles that are not suitable for directly entering the blast furnace but are beneficial to reducing the energy consumption of the blast furnace into hydrogen-rich reducing gas. , which can then be injected into the blast furnace together with hydrogen. Among them, prefabricating pulverized coal into hydrogen-rich reducing gas can eliminate the adverse effects of coal injection on blast furnace conditions; prefabricating coke, biomass particles and waste plastic particles into hydrogen-rich reducing gas can fully utilize resources. Application and recycling. By introducing the blast furnace gas into the hydrogen-rich reducing gas prefabricated furnace, the decarbonization of the blast furnace gas can be easily achieved. More importantly, through the comprehensive processing of the above-mentioned various resources by the hydrogen-rich reducing gas prefabricated furnace, the unified conversion into hydrogen-rich reducing gas can be realized according to the hydrogen-rich reducing gas during the subsequent mixed injection with pure hydrogen. As the composition changes, the control system dynamically adjusts the ratio of CO and H ₂ to achieve control of the reducing atmosphere and heat of the blast furnace, thereby enabling replaceable control of the furnace ore.

Compared with coke pellets, biomass pellets and waste plastic pellets have low density and burn quickly. If the three are evenly distributed, it will easily cause coke dices to accumulate in the material column in the hydrogen-rich reducing gas prefabricated furnace, causing the temperature inside the furnace to become unstable. All, causing fluctuations in furnace conditions and even safety accidents. In a further embodiment according to the present invention as shown in Figures 3 and 4, a double-cylinder spiral distributor is used at the feed inlet of the hydrogen-rich reducing gas prefabricated furnace 1, including an outer cylinder 2. The upper part of the outer cylinder 2 is a spiral material channel 3, and the lower part is an inner cylinder 4. The inner cylinder 4 extends downwardly below the outer cylinder 2 to such a length that its outlet is submerged into the material column in the hydrogen-rich reducing gas prefabricated furnace. A plurality of pressure equalizing holes 5 are provided in the part of the inner cylinder 4 that extends beyond the outer cylinder 2 to equalize the pressure between the inner cylinder 4 and the furnace to avoid unsmooth unloading. The mixture of coke, biomass particles and waste plastic particles in the inner cylinder 4 enters the spiral channel 3 from above. During the process of falling along the spiral channel, due to the high density of the coke, it falls under the inertial force. Under the action, its movement trajectory is closer to the outer cylinder, while biomass particles and waste plastic particles have low density, and their movement trajectory is closer to the inner cylinder. After passing through the spiral feed channel, most of the coke will enter the furnace through the shorter outer cylinder and participate in the reaction in the furnace earlier, while most of the biomass particles and waste plastic particles will pass through the longer inner cylinder. It enters the furnace, and the outlet of the inner cylinder is submerged in the material column. It will naturally descend into the material column along with the consumption of the material column, so it will participate in the reaction in the furnace later. In this way, although they enter the furnace at the same time, due to the different starting times of the reactions, the consumption speed of the biomass particles and waste plastic particles that burn faster and the coke that burns slower can be converged. In this way, during the preproduction process of hydrogen-rich reducing gas, the distribution of raw materials in the furnace material column can be more uniform, and the temperature in the furnace can be more balanced.

The preferred embodiments of the present invention are described in detail above. It should be understood that those skilled in the art can make many modifications and changes based on the concept of the present invention without creative efforts. Therefore, any technical solutions that can be obtained by those skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention and on the basis of the prior art should be within the scope of protection determined by the claims.

Claims (10)

1. A steel smelting system based on hydrogen-rich reducing gas injection is characterized by comprising a blast furnace and a hydrogen-rich reducing gas prefabricating furnace; injecting hydrogen-rich reducing gas and pure hydrogen from a hydrogen-rich reducing gas prefabricating furnace into the blast furnace; the generated blast furnace top gas circularly enters a hydrogen-rich reducing gas prefabricated furnace for decarburization; the material column in the hydrogen-rich reducing gas prefabricating furnace comprises pyrodine, biomass particles and waste plastic particles, and meanwhile, dry coal dust and pure oxygen are also injected into the hydrogen-rich reducing gas prefabricating furnace to prepare the hydrogen-rich reducing gas.

2. The hydrogen-rich reducing gas injection-based steel smelting system according to claim 1, wherein the blast furnace includes an iron-making blast furnace, a blast furnace for casting pig iron, a blast furnace for ferroalloy.

3. The steel smelting system based on hydrogen-rich reducing gas injection according to claim 1, wherein the dry pulverized coal is hydrogen-rich pulverized coal.

4. The steel smelting system based on the injection of hydrogen-rich reducing gas according to claim 1, wherein the pure hydrogen is green electricity prepared by blast furnace, converter gas power generation and photovoltaic, wind power, nuclear energy, hydraulic power and grid valley electricity, prepared by water electrolysis or prepared by reforming and purifying hydrogen-rich gas such as coke oven gas, natural gas and the like.

5. The hydrogen-rich reducing gas injection-based steel smelting system according to claim 1, wherein molten iron produced by the blast furnace is supplied to a steelmaking primary furnace including a converter, an electric arc furnace for producing carbon structural steel, alloy structural steel, low alloy high strength structural steel, carbon tool steel, alloy tool steel, high speed tool steel, high carbon cast iron, and stainless steel, and special purpose steels added with specific alloy elements including rare earth; the special purpose steel comprises marine corrosion resistant steel; section bar, plate, pipe, bar and wire rolled from the steel.

6. The steel smelting system based on the injection of the hydrogen-rich reducing gas, as set forth in claim 1, wherein a double-cylinder spiral distributor is adopted at the feed inlet of the hydrogen-rich reducing gas prefabricating furnace, comprising an outer cylinder; the upper part in the outer cylinder is a spiral material channel, and the lower part is an inner cylinder; the inner cylinder extends downwards below the outer cylinder, the length of the inner cylinder is set to enable the outlet of the inner cylinder to be immersed into a material column in the hydrogen-rich reducing gas prefabricating furnace, and a plurality of pressure equalizing holes are formed in the part of the inner cylinder extending beyond the outer cylinder so as to equalize the pressure in the inner cylinder and the furnace.

7. The steel smelting method based on hydrogen-rich reducing gas injection is characterized by comprising the following steps:

(1) Adding pyrodine, biomass particles and waste plastic particles into a hydrogen-rich reducing gas prefabricating furnace, spraying dry coal dust and pure oxygen at the same time, and burning to prepare the hydrogen-rich reducing gas;

(2) Mixing the hydrogen-rich reducing gas from the hydrogen-rich reducing gas prefabricating furnace with pure hydrogen and then spraying the mixture into a blast furnace;

(3) Introducing the generated blast furnace top gas into a hydrogen-rich reducing gas prefabricated furnace for decarburization;

(4) Simultaneously spraying pure oxygen into the blast furnace;

(5) Molten iron produced by a blast furnace is supplied to a steelmaking primary smelting furnace including a converter and an arc furnace to produce carbon structural steel, alloy structural steel, low alloy high strength structural steel, carbon tool steel, alloy tool steel, high speed tool steel, high carbon steel castings, high carbon iron castings and stainless steel.

8. The steel smelting method based on hydrogen-rich reducing gas injection according to claim 7, wherein the dry pulverized coal is hydrogen-rich pulverized coal.

9. The steel smelting method based on the injection of hydrogen-rich reducing gas according to claim 7, wherein pure hydrogen is green electricity prepared by blast furnace, converter gas power generation and photovoltaic, wind, nuclear, hydraulic and grid valley electricity, prepared by water electrolysis or prepared by reforming and purifying hydrogen-rich gas such as coke oven gas, natural gas and the like.

10. The steel smelting method based on hydrogen-rich reducing gas injection as claimed in claim 7, wherein a double-cylinder spiral distributor is adopted at the feed inlet of the hydrogen-rich reducing gas prefabricating furnace, and comprises an outer cylinder; the upper part in the outer cylinder is a spiral material channel, and the lower part is an inner cylinder; the inner cylinder extends downwards below the outer cylinder, the length of the inner cylinder is set to enable the outlet of the inner cylinder to be immersed into a material column in the hydrogen-rich reducing gas prefabricating furnace, and a plurality of pressure equalizing holes are formed in the part of the inner cylinder extending beyond the outer cylinder so as to equalize the pressure in the inner cylinder and the furnace; the mixture of the coke breeze, the biomass particles and the waste plastic particles enters the spiral material channel from the upper part, and the movement track of the coke breeze is closer to the outer cylinder under the action of inertia because the density of the coke breeze is high in the process of falling along the spiral material channel, and the density of the biomass particles and the waste plastic particles is low, and the movement track of the coke breeze is closer to the inner cylinder; after the spiral material channel, most of the coke breeze enters the furnace from the shorter outer cylinder to participate in the reaction in the furnace earlier, and most of the biomass particles and waste plastic particles enter the furnace from the longer inner cylinder to participate in the reaction in the furnace later.