CO2 circulating injection ironmaking method and system of hydrogen-rich carbon circulating oxygen blast furnace

Abstract

The invention discloses a CO2 circulating injection ironmaking method of a hydrogen-rich carbon circulating oxygen blast furnace, which comprises the following steps: heating CO2 separated and captured from top gas of the blast furnace to 2500 DEG C or above, and then circularly injecting into the blast furnace from a tuyere; and further purifying the residual CO and H2 in the top gas of the blast furnace to prepare a chemical product. The invention further discloses a CO2 circulating injection ironmaking system of the hydrogen-carbon-rich circulating oxygen blast furnace. The method solves the problems that the carbon emission reduction potential of a hydrogen-rich carbon circulating oxygen blast furnace process is not fully exerted, and CO2 separated and captured from top gas is not fully utilized.

Description

Technical Field

[0001] The present invention relates to blast furnace ironmaking technology, and more specifically, to a CO2 circulating injection ironmaking method and system for a hydrogen-rich carbon circulating oxygen blast furnace. Background Art

[0002] The fuel consumption per ton of iron in the existing blast furnace process is close to the theoretical limit. Without major changes, there is very limited room to continue to reduce fuel consumption and CO2 emissions. The chemical energy utilization rate of carbon in advanced blast furnaces is about 65%, and the remaining 35% of the chemical energy is taken away by by-product gas in the form of CO. The by-product gas also contains a large amount of N2 and CO2, which are difficult to be further utilized by the blast furnace due to thermodynamic and kinetic conditions. It can only be used at low quality through combustion and heat release. After removing CO2 from the top gas of the blast furnace, returning it to the blast furnace for use is an idea for efficient utilization of the chemical energy of the top gas. The economical removal of CO2 from the top gas requires reducing the nitrogen content in the gas. The top gas circulation needs to be combined with the blast furnace full oxygen to achieve this, and it can also avoid the accumulation of N2 during the gas circulation process. The core of the new process is to achieve full utilization of carbon chemical energy through carbon circulation, thereby achieving a significant reduction in carbon in the blast furnace. With carbon circulation, the large-scale use of hydrogen-rich substances will not waste the chemical energy of hydrogen, and hydrogen can also be circulated in the blast furnace, thereby reducing the fossil energy consumption of the blast furnace process.

[0003] Based on years of extensive research, a new hydrogen-rich carbon circulating oxygen blast furnace (HyCROF) process based on the blast furnace-converter long process has been developed in China. The main features of this new process are the use of full oxygen smelting, CO2 removal from top gas, high-temperature heating of high-reduction potential gas, and high-temperature gas circulation injection. The complete utilization of carbon chemical energy is achieved through carbon circulation, thereby significantly reducing carbon emissions from the iron-making process.

[0004] HyCROF has achieved a significant reduction in carbon emissions, but there is still a large gap from the theoretical limit of carbon reduction. The CO2 separated and captured in the top gas has not been effectively utilized. To ultimately achieve the goal of carbon neutrality in the long process of blast furnace-converter, the HyCROF process needs to be iteratively upgraded. From the perspective of the ultimate utilization of carbon chemical energy, there is room for improvement in the current carbon utilization efficiency and circulation volume of circulating gas. On the one hand, CO, the main component of circulating gas, is prone to carbon deposition during the heating process to form carbon deposits. Properly increasing the CO2 content in the circulating gas can eliminate the carbon precipitated in the heating furnace and reduce carbon losses. On the other hand, part of the top gas is used for heating the circulating gas in the hot blast furnace before decarbonization, and it is not fully recycled. It is necessary to use carbon as much as possible for iron ore reduction and reduce carbon consumption for heating, so as to achieve the ultimate utilization of carbon chemical energy. Plasma electric heating technology can quickly heat the reducing coal gas to above 2500℃, and can ensure that the temperature of the gas entering the vortex zone of the tuyere reaches the theoretical combustion temperature level. The physical heat required for smelting is all provided by clean electricity, and no carbon is used for heating. The top gas can achieve 100% circulation injection. If the cost of producing green electricity is greatly reduced to a level that can fully support industrial applications in the near future, it is entirely possible to use green electricity to apply plasma heating and other electric heating technologies outside the furnace to heat the circulating coal gas to ultra-high temperatures and then spray it into the tuyere, so that the physical heat carried by the ultra-high temperature circulating coal gas meets the carbon consumption required for smelting heating and heating (theoretically accounting for about 2 / 3 of the total furnace heat expenditure). The blast furnace will no longer need to blast hot air or oxygen to combust with coke or coal powder to release heat, but only needs to meet the heat required for reducing carbon. The scope of metallurgical electrification will be greatly expanded, the carbon consumption of blast furnaces will be significantly reduced, and the potential for carbon emission reduction is huge.

[0005] Under the current process conditions of HyCROF, to achieve carbon neutrality in the long blast furnace process, about 40% of carbon emissions still need to be achieved through CCU / S. However, the carbon emissions of the blast furnace ironmaking process are huge (accounting for about 70% of the entire steel process), and CO2 is an extremely stable chemical substance. Large-scale resource utilization has high energy consumption and poor economic efficiency. There is currently no record of industrial application. Summary of the invention

[0006] In view of the defects existing in the prior art, the purpose of the present invention is to provide a CO2 circulating injection ironmaking method and system for a hydrogen-rich carbon circulating oxygen blast furnace, which solves the problems that the carbon emission reduction potential of the hydrogen-rich carbon circulating oxygen blast furnace process has not been fully utilized and the CO2 separated and captured in the top gas has not been fully utilized.

[0007] To achieve the above object, the present invention adopts the following technical solution:

[0008] A first aspect of the present invention provides a CO2 circulating injection ironmaking method for a hydrogen-rich carbon circulating oxygen blast furnace, comprising the following steps:

[0009] S1: heating the CO2 separated and captured from the top gas of the blast furnace to above 2500°C, and then circulating and injecting it into the blast furnace from the tuyere;

[0010] S2: The remaining CO and H2 in the top gas of the blast furnace are further purified to produce chemical products.

[0011] Preferably, the CO2 separated and captured from the top gas of the blast furnace is heated to above 2500°C and then circulated and injected into the blast furnace from the tuyere, which specifically includes the following steps:

[0012] S11, adding iron-containing raw materials, coke and slag-making solvent from the top of the blast furnace;

[0013] S12, starting the capture unit and the CO2 heating device to separate and capture the CO2 in the top gas of the blast furnace and heat it to above 2500° C.;

[0014] S13, the heated CO2 gas is sprayed into the blast furnace from the tuyere, blows various furnace materials in the blast furnace to form a physical cyclone space, and reacts with the coke to generate CO by carbon melting, completing the initial distribution of high-temperature coal gas. CO fully contacts with the furnace materials during the rising process, and reduces iron oxides step by step;

[0015] S14, the iron-containing raw material is reduced to metallic iron and carburized with the high-temperature coke, moves downward in the blast furnace, transfers heat with the CO2 gas at the tuyere and the coke to generate CO in the lower part of the blast furnace, and gradually melts and drips. The dripping slag and molten iron complete slag-metal interface reaction and separation in the blast furnace, and are discharged from the iron mouth of the blast furnace.

[0016] Preferably, the adding of the iron-containing raw material, coke and slag-making solvent in step S11 specifically includes:

[0017] The blast furnace is filled with a layer of coke and a layer of ore formed by mixing the iron-containing raw material and the slag-making solvent in the order of distribution to the material line position.

[0018] Preferably, in step S12, the CO2 heating device is powered by a green energy unit;

[0019] The green energy unit comprises a power generation device and an energy storage battery which are connected in sequence, and the energy storage battery is connected to the CO2 heating device.

[0020] Preferably, the separation and capture of CO2 in the top gas of the blast furnace in step S12 specifically includes:

[0021] The CO2 in the top gas of the blast furnace passes through a gas compressor, a decarbonization device and a CO2 compressor in sequence;

[0022] The CO2 compressor is connected to the CO2 heating device through a spray valve station.

[0023] Preferably, the blowing speed of the tuyere in step S13 is 200-300 m / s.

[0024] Preferably, the remaining CO and H2 in the top gas of the blast furnace are further purified to produce chemical products, specifically including:

[0025] The decarbonization device is then connected to a chemical production device;

[0026] The remaining CO and H2 in the top gas of the blast furnace are purified, H2 is added, the temperature and pressure parameters are adjusted, and they enter the chemical production device under the action of a catalyst to be made into chemical products.

[0027] Preferably, the chemical product is methanol and its derivatives.

[0028] The second aspect of the present invention provides a CO2 circulating injection ironmaking system for a hydrogen-rich carbon circulating oxygen blast furnace, comprising a gas compressor, a decarbonization device, a CO2 compressor, an injection valve station and a CO2 heating device connected in sequence to the top gas outlet of the blast furnace;

[0029] The CO2 heating device is connected to the blast furnace through a tuyere;

[0030] The decarbonization device is connected to a chemical production device;

[0031] The CO2 heating device is connected to a green energy unit;

[0032] The CO2 circulating injection ironmaking system of the hydrogen-rich carbon circulating oxygen blast furnace realizes the CO2 circulating injection ironmaking method of the hydrogen-rich carbon circulating oxygen blast furnace provided in the first aspect of the present invention.

[0033] Preferably, the green energy unit comprises a power generation device and an energy storage battery connected in sequence;

[0034] The energy storage battery is connected to the CO2 heating device.

[0035] The CO2 circulating injection ironmaking method and system for a hydrogen-rich carbon circulating oxygen blast furnace provided by the present invention has the following beneficial effects:

[0036] (1) All CO2 produced by the blast furnace is recycled and injected, and no CO2 gas is discharged. CO and H2 are coupled with chemicals as by-products to synthesize chemical products such as ethanol, and the remaining carbon is solidified. The process itself does not produce any carbon emissions. Combined with green electricity heating and circulating CO2, carbon neutrality in the blast furnace process can be achieved;

[0037] (2) The coupling of renewable energy power generation system and energy storage battery solves the problem of large fluctuations in power generation and energy waste caused by intermittent and random power generation of renewable energy such as photovoltaic and wind power, and can provide continuous and stable green electricity for the CO2 heating system;

[0038] (3) The smelting process does not require blasting and oxygen, and does not burn coke. The heated ultra-high temperature CO2 reacts with coke at the tuyere to produce CO to reduce iron ore, keeping the blast furnace in uninterrupted production. Therefore, there is no need to build hot blast furnaces, oxygen generators, blowers and their associated pipelines, and the process is more compact and occupies a smaller area. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a schematic diagram of the framework structure of the CO2 circulating injection ironmaking system of the hydrogen-rich carbon circulating oxygen blast furnace of the present invention. DETAILED DESCRIPTION

[0040] In order to better understand the above technical solution of the present invention, the technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0041] Combination Figure 1 As shown, the present invention provides a CO2 circulating injection ironmaking method for a hydrogen-rich carbon circulating oxygen blast furnace:

[0042] Green electricity is used to heat the CO2 separated and captured from the top gas of blast furnace 9 to an ultra-high temperature of over 2500°C through plasma heating and other methods, and then circulated and injected into blast furnace 9 from the tuyere. This can completely replace the heat release of carbon combustion, realize oxygen-free smelting, compensate for part of the carbon chemical energy, and greatly reduce the carbon emissions of the blast furnace.

[0043] The remaining CO and H2 in the top gas of blast furnace 9 are further purified and recycled through the combined production of tempering and steel to produce chemical products such as methanol, thus achieving carbon neutrality in the blast furnace process.

[0044] The process of heating the CO2 separated and captured from the top gas of the blast furnace 9 to above 2500°C and then circulating and injecting it into the blast furnace 9 from the tuyere specifically includes the following steps:

[0045] S1. Add iron-containing raw materials (sintered ore, pelletized ore, lump ore, etc.), coke with a ton iron to coke ratio of 300-500 kg, and slag-making solvent from the top of the blast furnace 9, and fill them to the set material line position on the blast furnace 9 in the order of one layer of coke and one layer of ore (iron-containing raw materials and slag-making solvent are mixed and weighed).

[0046] S2, start the power generation device 1, supply the CO2 heating device 7 to heat the circulating CO2, separate and capture the CO2 in the top gas of the blast furnace 9 and heat it to above 2500°C. The surplus electricity is stored in the energy storage battery 2 to supplement the system green electricity when the power is insufficient.

[0047] S3, CO2 in the top gas of the blast furnace 9 is purified by dust removal and pressurized by the gas compressor 3, and then enters the decarbonization device 4 to remove CO2 and dehumidify, and separate and capture the CO2 in the top gas. The captured CO2 is pressurized and the flow rate is adjusted at the injection valve station 6, and is heated to an ultra-high temperature of more than 2500℃ by the CO2 heating device 7, and then sprayed into the furnace from the lower tuyere of the blast furnace 9.

[0048] S4. The heated CO2 gas is injected into the blast furnace 9 from the tuyere at a speed of 200-300m / s, blowing various furnace materials in the blast furnace 9 to form a physical vortex space, and reacting with coke to produce CO by carbon melting, completing the initial distribution of high-temperature coal gas. The initially distributed high-temperature coal gas flows from bottom to top, and the raw fuel added from the top of the blast furnace 9 moves from top to bottom under the influence of gravity, and the high-temperature coal gas and furnace materials such as coke and iron ore move in the opposite direction to complete the heat transfer.

[0049] S5. After the iron-containing raw material is reduced to metallic iron, it is carburized with high-temperature coke and moves downward in the blast furnace 9. In the lower part of the blast furnace 9, it transfers heat with the CO2 gas at the tuyere and the CO generated by the reaction with the coke, and gradually melts and drips. The dripping slag and molten iron complete the slag-metal interface reaction and separation in the blast furnace 9 and are discharged from the iron mouth of the blast furnace 9.

[0050] The remaining CO and H2 in the top gas of the blast furnace 9 are further purified to produce chemical products, including:

[0051] The decarbonization device 4 is then connected to the chemical production device 8 .

[0052] The remaining CO and H2 in the top gas of the blast furnace 9 are purified, and H2 is added according to the volume ratio of H2 to CO of 2:1. The temperature, pressure and other parameters are adjusted, and the gas enters the chemical production device 8 under the action of the catalyst to produce chemical products such as methanol (and its derivatives).

[0053] The green energy unit of the present invention uses green electricity generated by accessing a photovoltaic power station, but is not limited to this method, and also includes green electricity generated by clean energy such as wind energy, hydropower, geothermal energy and bioenergy, and supplies the CO2 heating device 7 through the energy storage battery 2 to heat CO2. Surplus electricity is stored in the energy storage battery 2, and the system green electricity is supplemented when power is insufficient due to climate change factors such as insufficient sunlight and wind power.

[0054] In the above step S4, after the ultra-high temperature CO2 is sprayed into the blast furnace 9 from the tuyere at a speed of about 200 to 300 m / s, it blows various charges in the furnace to form a physical vortex space and completes the initial distribution of the high temperature coal gas and the flow from bottom to top. The raw materials added from the top of the blast furnace 9 move from top to bottom under the influence of gravity, and the high temperature coal gas and charges such as coke and iron ore move in the opposite direction to complete the heat transfer.

[0055] The ultra-high temperature CO2 first reacts with the coke to dissolve carbon in the tuyere cyclotron: CO2+C→2CO; if the temperature reaches above 3000℃, the CO2 decomposition reaction will also occur: CO2→CO+O2, and the generated oxygen will undergo an incomplete combustion reaction in the environment of excess carbon in the tuyere: 2C+O2→2CO. The sum of the two reactions is still: CO2+C→2CO. That is, under the ultra-high temperature and excess carbon conditions in the tuyere cyclotron, all CO2 is converted into CO. The CO produced by the carbon dissolution reaction fully contacts the charge during the rising process, and undergoes an indirect reduction reaction with the Fe2O3 in the iron ore: Fe2O3+3CO→2FeO+3CO2. Due to the large amount of CO in the furnace, some CO still enters the top gas directly before it has time to reduce the iron oxides.

[0056] Part of the crystal water in the charge undergoes a water-gas reaction in the high-temperature zone of about 800°C: H2O+C→H2+CO, which will generate a very small amount of H2 and CO. Moreover, the hydrogen gas has a fast flow rate and strong penetration, and the gas-solid reduction reaction with iron oxides cannot be completely carried out, and a small amount of unused hydrogen still enters the top gas. The top gas finally formed contains a large amount of CO, CO2 and a very small amount of H2. In order to realize the cyclic injection of CO2 and the resource utilization of CO and H2, the top gas is subjected to dust removal and purification by the gas cleaning device, and the decarbonization device 4 is pressurized to remove CO2 and dehumidify, so as to realize the separation of CO2 from CO and H2. The CO2 captured by the decarbonization device 4 is pressurized by the CO2 compressor 5, and the injection valve station 6 adjusts the pressure and flow, enters the CO2 heating device 7 for heating, and then circulates and sprays into the tuyere.

[0057] According to the principle that the total heat required for reduction is certain at a certain output level, the less the circulating CO2 injection amount, the higher the heating temperature required, and the greater the circulating CO2 injection amount, the lower the heating temperature required. Since there is still a certain degree of coke direct reduction reaction in the furnace, the circulating CO2 injection amount and the temperature of the electric heating can be adjusted by controlling the level of direct reduction in the furnace to achieve internal heat balance of the blast furnace.

[0058] The present invention implements electrification transformation, uses green electricity outside the furnace to heat CO2 to an ultra-high temperature, and then circulates and injects it from the tuyere. CO2 is reduced to CO at ultra-high temperature, which is equivalent to the large amount of chemical energy consumed in the original furnace to reduce iron ore with CO being replenished by green electricity, and the carbon used for reduction in the furnace is significantly reduced. Moreover, there is no carbon precipitation reaction during the CO2 heating and injection process, and there is no carbon loss. At the same time, 100% of the top gas can be circulated and injected, and the carbon emission of the blast furnace can be further reduced. Combining the currently very mature resource utilization methods such as CO+H2 to produce methanol to implement steel production, carbon neutrality in the blast furnace process can be achieved.

[0059] Refer to Figure 1 As shown, the present invention also provides a CO2 circulating injection ironmaking system for a hydrogen-rich carbon circulating oxygen blast furnace, comprising a gas compressor 3, a decarbonization device 4, a CO2 compressor 5, an injection valve station 6 and a CO2 heating device 7 which are sequentially connected to the top gas outlet of the blast furnace 9.

[0060] The CO2 heating device 7 is connected to the bottom of the blast furnace 9 through the tuyere.

[0061] The decarbonization device 4 is connected to a chemical production device 8 for synthesizing chemical products such as methanol (and its derivatives).

[0062] The CO2 heating device 7 is connected to a green energy unit.

[0063] The CO2 circulating injection ironmaking system of the hydrogen-rich carbon circulating oxygen blast furnace of the present invention realizes the CO2 circulating injection ironmaking method of the hydrogen-rich carbon circulating oxygen blast furnace of the present invention.

[0064] The green energy unit comprises a power generation device 1 and an energy storage battery 2 which are connected in sequence.

[0065] The energy storage battery 2 is connected to the CO 2 heating device 7 .

[0066] Example 1

[0067] This embodiment 1 is applied to the hydrogen-rich carbon cycle oxygen blast furnace process (HyCROF), and adds a renewable energy (photovoltaic, wind energy, etc.) power generation device 1 and a CO2 heating device 7 on the basis of the hydrogen-rich carbon cycle oxygen blast furnace process. The CO2 separated from the top gas is heated by the CO2 heating device 7 and then sprayed into the tuyere in a cycle. The remaining CO+H2 is used for resource utilization such as methanol production to implement tempering co-production, which can achieve carbon neutrality in the blast furnace process. The specific implementation process is as follows:

[0068] (1) According to theoretical calculation, under the condition of coke ratio of 400kg / tHM, the circulating CO2 injection amount and the temperature of electric heating can be adjusted by controlling the direct reduction level in the furnace to achieve internal heat balance of the blast furnace. When Rd = 0.4, the CO2 that needs to be circulated and injected tends to the lower limit of 400Nm3 / tHM, the corresponding heating temperature needs to be higher, about 6000°C. The iron consumption per ton of this process is shown in Table 1. If the electrothermal efficiency is calculated as 75%, the CO2 heating device 7 needs to consume 2205 kwh / t of green electricity, that is, the photovoltaic power generation required for the ironmaking process of this embodiment 1 is 2205 kwh / t.

[0069] Table 1 Theoretical calculation parameters of top gas CO2 tuyere circulation injection (Rd=0.4)

[0070]

[0071] (2) Iron-containing raw materials (sintered ore, pelletized ore and lump ore, etc.) and a certain amount of coke and slag-forming flux are added from the top of blast furnace 9, wherein the amount of coke added is calculated based on the ore-coke ratio and batch weight of 400 kg per ton of iron for charging calculation and charging.

[0072] (3) The green electricity generated by the power generation device 1 first passes through the energy storage battery 2, and then is supplied to the CO2 heating device 7 to heat the circulating CO2. When the power is insufficient, the surplus power stored in the energy storage battery 2 supplements the system green electricity.

[0073] (4) After the top gas is purified by dust removal and pressurized by the gas compressor 3, it enters the decarbonization device 4 to remove CO2 and dehumidify, and separate and capture the CO2 in the top gas. The captured CO2 is pressurized and the flow rate is adjusted at the injection valve station 6, and heated to an ultra-high temperature of 6000°C by the CO2 heating device 7, and sprayed into the furnace from the lower tuyere of the blast furnace 9. The inner diameter of the tuyere is determined according to the amount of CO2 blown in each tuyere to ensure that the wind speed of the ultra-high temperature CO2 blown in is maintained in the range of 200-300m / s. The gas components before and after decarbonization and dehumidification of the other top gas are shown in Table 2. Most of it is CO, and there is only a very small amount of H2. After purification, H2 is added according to the volume ratio of H2 to CO of 2:1, and the temperature, pressure and other parameters are adjusted. Under the action of the catalyst, it enters the chemical production device 8 to synthesize methanol.

[0074] Table 2 Gas composition before and after dehumidification of top gas (Rd = 0.4)

[0075] Component / % CO <![CDATA[CO2]]> <![CDATA[H2]]> <![CDATA[H2O]]> Before decarbonization and dehumidification 57.6 40.5 0.3 1.6 After decarbonization and dehumidification 99.5 0 0.5 0

[0076] (5) The ultra-high temperature CO2 blown in at high speed blows various furnace materials in the furnace to form a physical vortex space, and reacts with coke to produce CO by carbon dissolution, completing the initial distribution of high temperature gas and flowing from bottom to top. The raw materials added from the top of the blast furnace 9 move from top to bottom under the influence of gravity, and the high temperature gas moves in the opposite direction with furnace materials such as coke and iron ore to complete the heat transfer.

[0077] (6) After the iron ore is reduced to metallic iron, it is carburized with high-temperature coke and continues to move downward. In the lower part of the blast furnace 9, it transfers heat with the ultra-high temperature circulating CO2 injected from the tuyere and the CO generated by the reaction with the coke, and gradually melts and drips. The dripping slag and molten iron complete the slag-metal interface reaction and separation in the furnace, and are continuously discharged from the iron mouth.

[0078] Example 2

[0079] To further increase the circulating gas injection rate, the direct reduction degree (Rd) of the smelting process in Example 2 is 0.1, and the specific implementation process is as follows:

[0080] (1) The larger the circulating gas volume, the lower the direct reduction degree. At the same time, the increase in circulating gas volume will reduce the gas temperature that needs to be heated. Still under the condition of coke ratio of 400kg / tHM, according to theoretical calculation, when Rd = 0.1, the CO2 that needs to be injected in circulation reaches the upper limit of 514Nm 3 / tHM, the corresponding heating temperature can be lowered to about 4700°C. The iron consumption per ton of the process is shown in Table 3. If the electrothermal efficiency is calculated as 75%, the CO2 heating device 7 needs to consume 2205 kwh / t of green electricity, that is, the photovoltaic power generation required for the ironmaking process of this embodiment 2 is 2205 kwh / t.

[0081] Table 3 Theoretical calculation parameters of top gas CO2 tuyere circulation injection (Rd = 0.1)

[0082]

[0083] (2) Iron-containing raw materials (sintered ore, pelletized ore and lump ore, etc.) and a certain amount of coke and slag-forming flux are added from the top of blast furnace 9, wherein the amount of coke added is calculated based on the ore-coke ratio and batch weight of 400 kg per ton of iron for charging calculation and charging.

[0084] (3) The green electricity generated by the power generation device 1 first passes through the energy storage battery 2, and then is supplied to the CO2 heating device 7 to heat the circulating CO2. When the power is insufficient, the surplus power stored in the energy storage battery 2 supplements the system green electricity.

[0085] (4) After the top gas is purified by dust removal and pressurized by the gas compressor 3, it enters the decarbonization device 4 to remove CO2 and dehumidify, and separate and capture the CO2 in the top gas. The captured CO2 is pressurized and the flow rate is adjusted at the injection valve station 6, and heated to an ultra-high temperature of 4700°C by the CO2 heating device 7, and sprayed into the furnace from the lower tuyere of the blast furnace 9. The inner diameter of the tuyere is determined according to the amount of CO2 blown into each tuyere to ensure that the wind speed of the ultra-high temperature CO2 blown in is maintained in the range of 200-300m / s. The gas components before and after decarbonization and dehumidification of the other top gas are shown in Table 4. Most of it is CO, and there is only a very small amount of H2. After purification, H2 is added according to the volume ratio of H2 to CO of 2:1, and the temperature, pressure and other parameters are adjusted. Under the action of the catalyst, it enters the chemical production device 8 to synthesize methanol.

[0086] Table 4 Gas composition before and after dehumidification of top gas (Rd = 0.1)

[0087] Component / % CO <![CDATA[CO2]]> <![CDATA[H2]]> <![CDATA[H2O]]> Before decarbonization and dehumidification 51.7 46.5 0.3 1.5 After decarbonization and dehumidification 99.4 0 0.6 0

[0088] (5) The ultra-high temperature CO2 blown in at high speed blows various furnace materials in the furnace to form a physical vortex space, and reacts with coke to produce CO by carbon dissolution, completing the initial distribution of high temperature gas and flowing from bottom to top. The raw materials added from the top of the blast furnace 9 move from top to bottom under the influence of gravity, and the high temperature gas moves in the opposite direction with furnace materials such as coke and iron ore to complete the heat transfer.

[0089] (6) After the iron ore is reduced to metallic iron, it is carburized with high-temperature coke and continues to move downward. In the lower part of the blast furnace 9, it transfers heat with the ultra-high temperature circulating CO2 injected from the tuyere and the CO generated by the reaction with the coke, and gradually melts and drips. The dripping slag and molten iron complete the slag-metal interface reaction and separation in the furnace, and are continuously discharged from the iron mouth.

[0090] Those skilled in the art should recognize that the above embodiments are only used to illustrate the present invention, and are not intended to limit the present invention. As long as they are within the spirit of the present invention, any changes or modifications to the above embodiments will fall within the scope of the claims of the present invention.

Claims

1. A CO2 circulating injection ironmaking method for a hydrogen-rich carbon circulating oxygen blast furnace, characterized in that: The following steps are involved: S1: heating the CO2 separated and captured from the top gas of the blast furnace to above 2500°C, and then circulating and injecting it into the blast furnace from the tuyere; S2: The remaining CO and H2 in the top gas of the blast furnace are further purified to produce chemical products.

2. The CO2 circulating injection ironmaking method for a hydrogen-rich carbon circulating oxygen blast furnace according to claim 1, characterized in that: Step S1 specifically includes the following steps: S11, adding iron-containing raw materials, coke and slag-making solvent from the top of the blast furnace; S12, starting the capture unit and the CO2 heating device to separate and capture the CO2 in the top gas of the blast furnace and heat it to above 2500° C.; S13, the heated CO2 gas is sprayed into the blast furnace from the tuyere, blows various furnace charges in the blast furnace to form a physical cyclonic empty area, and reacts with the coke to generate CO by carbon melting, completing the initial distribution of high-temperature coal gas; CO fully contacts with the furnace charge during the rising process, and reduces iron oxides step by step; S14, the iron-containing raw material is reduced to metallic iron and carburized with the high-temperature coke, moves downward in the blast furnace, transfers heat with the CO2 gas at the tuyere and the coke to generate CO in the lower part of the blast furnace, and gradually melts and drips. The dripping slag and molten iron complete slag-metal interface reaction and separation in the blast furnace, and are discharged from the iron mouth of the blast furnace.

3. The CO2 circulating injection ironmaking method for a hydrogen-rich carbon circulating oxygen blast furnace according to claim 2, characterized in that: The addition of the iron-containing raw material, coke and slag-making solvent in step S11 specifically includes: The blast furnace is filled with a layer of coke and a layer of ore formed by mixing the iron-containing raw material and the slag-making solvent in the order of distribution to the material line position.

4. The CO2 circulating injection ironmaking method for a hydrogen-rich carbon circulating oxygen blast furnace according to claim 2, characterized in that: In step S12, the green energy unit supplies power to the CO2 heating device; The green energy unit comprises a power generation device and an energy storage battery which are connected in sequence, and the energy storage battery is connected to the CO2 heating device.

5. The CO2 circulating injection ironmaking method for a hydrogen-rich carbon circulating oxygen blast furnace according to claim 2, characterized in that: The separation and capture of CO2 in the top gas of the blast furnace in step S12 specifically includes: The CO2 in the top gas of the blast furnace passes through a gas compressor, a decarbonization device and a CO2 compressor in sequence; The CO2 compressor is connected to the CO2 heating device through a spray valve station.

6. The CO2 circulating injection ironmaking method for a hydrogen-rich carbon circulating oxygen blast furnace according to claim 2, characterized in that: The blowing speed of the air outlet in step S13 is 200-300 m / s.

7. The CO2 circulating injection ironmaking method for a hydrogen-rich carbon circulating oxygen blast furnace according to claim 5, characterized in that: Step S2 specifically includes: The decarbonization device is then connected to a chemical production device; The remaining CO and H2 in the top gas of the blast furnace are purified, H2 is added, the temperature and pressure parameters are adjusted, and they enter the chemical production device under the action of a catalyst to be made into chemical products.

8. The CO2 circulating injection ironmaking method for a hydrogen-rich carbon circulating oxygen blast furnace according to claim 7, characterized in that: The chemical products are methanol and its derivatives.

9. A CO2 circulating injection ironmaking system for a hydrogen-rich carbon circulating oxygen blast furnace, characterized in that: It includes a gas compressor, a decarbonization device, a CO2 compressor, an injection valve station and a CO2 heating device which are sequentially connected to the top gas outlet of the blast furnace; The CO2 heating device is connected to the blast furnace through a tuyere; The decarbonization device is connected to a chemical production device; The CO2 heating device is connected to a green energy unit; The CO2 circulating injection ironmaking system of the hydrogen-rich carbon circulating oxygen blast furnace realizes the CO2 circulating injection ironmaking method of the hydrogen-rich carbon circulating oxygen blast furnace as described in any one of claims 1-8.

10. The CO2 circulating injection ironmaking system for a hydrogen-rich carbon circulating oxygen blast furnace according to claim 9, characterized in that: The green energy unit includes a power generation device and an energy storage battery connected in sequence; The energy storage battery is connected to the CO2 heating device.

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