Iron-making system and method for coupling solid oxide electrolysis and blast furnace waste heat utilization

Abstract

The invention relates to an ironmaking system and method for coupling solid oxide electrolysis and blast furnace waste heat utilization, the system comprises a solid oxide electrolysis system, a hot air system, a heat exchange network and a blast furnace body, the solid oxide electrolysis system generates hydrogen and oxygen through electrolyzed water under coupling driving of an external power supply and blast furnace waste heat; the hot air system is used for continuously conveying high-temperature hot air to a blast furnace by taking blast furnace gas as fuel; according to the heat exchange system, waste heat generated by a blast furnace is used for heating fuel at an inlet of a solid oxide electrolytic tank and hydrogen at an inlet of the blast furnace; the blast furnace body is used for reducing ore to smelt pig iron. Waste heat in the blast furnace ironmaking process is recycled through the heat exchange network, inlet water of a solid oxide electrolysis system and blast furnace inlet hydrogen are heated, power consumption in the electrolytic hydrogen production process is effectively reduced, and meanwhile the device has important significance on deep energy conservation and carbon reduction of the blast furnace hydrogen-rich metallurgy technology.

Description

Technical Field

[0001] The present invention relates to an ironmaking system and method for coupling solid oxide electrolysis with blast furnace waste heat utilization, belonging to the technical field of hydrogen energy utilization and blast furnace ironmaking, and specifically to a technical solution for using hydrogen and oxygen generated by electrolysis in a blast furnace ironmaking process and improving the overall ironmaking efficiency by utilizing blast furnace waste heat. Background Art

[0002] The traditional blast furnace ironmaking process uses coke as a reducing agent and fuel to reduce iron ore into iron. Therefore, blast furnace ironmaking is accompanied by the production of a large amount of greenhouse gases such as carbon dioxide. With global warming and the intensification of the greenhouse effect, it is urgent to develop new steel smelting technologies to promote the green transformation of the steel industry and reduce energy consumption and carbon emissions in the ironmaking process. In recent years, hydrogen, as a clean reducing agent and fuel, has been used to replace coke in the blast furnace ironmaking process due to its strong reducing ability and clean and low-carbon characteristics. It is of great significance to energy conservation and carbon reduction in difficult-to-decarbonize fields such as blast furnace ironmaking.

[0003] Blast furnace hydrogen-rich smelting technology is one of the main hydrogen metallurgical processes. Its technical principle is to inject pure hydrogen or hydrogen-rich gas during the blast furnace smelting process to reduce the iron ore in the furnace, reduce the injection amount of coke / coal, and reduce the generation of CO2 from the source.

[0004] However, the current blast furnace hydrogen-rich smelting technology has the following problems:

[0005] When a large amount of hydrogen is injected into the blast furnace, hydrogen reduction is a strong endothermic reaction and the temperature inside the furnace decreases. It is particularly critical to solve the heat compensation problem of the blast furnace. In the blast furnace ironmaking process, by-products such as blast furnace gas and blast furnace slag are produced, which contain a large amount of waste heat that is not fully utilized. Therefore, the waste heat utilization rate of blast furnace ironmaking is low, and attention should be paid to waste heat recovery and utilization technology. At present, in the blast furnace system that uses water electrolysis to produce hydrogen as the source of hydrogen, water electrolysis to produce hydrogen and blast furnace are still two relatively independent systems. The hydrogen metallurgical process has not yet been optimized from the perspective of the entire process, and we continue to explore new hydrogen metallurgical systems that are deeply coupled with water electrolysis to produce hydrogen and blast furnace ironmaking.

[0006] The invention patent CN115341057A published on November 15, 2022, involves a blast furnace hydrogen-rich smelting system and method, including a power generation system, a water electrolysis system, a blowing system, a preheating system, and a hot air system. Renewable energy is used to generate electricity to drive water electrolysis, and the generated hydrogen is preheated by the preheating system and then enters the blast furnace body for use. On the one hand, the use of hydrogen can achieve the emission reduction effect of steel smelting. On the other hand, the use of renewable energy for power generation can solve the energy waste problem of renewable energy. However, the system does not take into account the effective utilization of waste heat resources in the blast furnace ironmaking process. It is only a blast furnace hydrogen-rich smelting system that simply couples water electrolysis to produce hydrogen with the blast furnace.

[0007] The invention patent CN116732259A published on September 12, 2023, involves a smelting method and system for injecting hydrogen-rich gas into a blast furnace, which mainly includes heating and cracking green ammonia to obtain hydrogen and nitrogen, and mixing with the remaining green ammonia to obtain hydrogen-rich gas and then entering the blast furnace for smelting. The use of green ammonia as a carrier for hydrogen transportation solves the problems of poor safety and transportation difficulties of hydrogen. At the same time, the injection of hydrogen-rich gas in the blast furnace indirectly realizes the stable injection of green pure hydrogen in the blast furnace, improves the indirect reduction degree of the blast furnace, and reduces carbon emissions in the ironmaking process. However, the system uses electric heating to preheat the hydrogen-rich gas to provide part of the heat for hydrogen-rich smelting in the blast furnace. The hydrogen preheating process causes high power consumption in the system.

[0008] The invention patent CN115522003A published on December 27, 2022, involves a hydrogen-rich blast furnace ironmaking system based on energy-quality conversion and its production control method, including an electrolytic water system, a hydrogen injection valve group, an oxygen injection valve group, and a hydrogen preheating system. The hydrogen produced by electrolytic water is pressurized by a compressor and sent to the hydrogen preheating system for preheating. The preheated hydrogen is injected into the blast furnace, and the oxygen produced by electrolytic water is injected into the blast furnace after the pressure and flow are adjusted by the oxygen injection valve group. However, the system uses electric heating to preheat hydrogen, and the preheating process consumes a lot of electricity. The electrolytic hydrogen production and the blast furnace are simply integrated, and the waste heat of the blast furnace ironmaking process is not effectively recovered, and the waste heat utilization efficiency is low. Summary of the invention

[0009] In order to overcome the above-mentioned deficiencies of the prior art, the present invention provides an ironmaking system and method for coupling solid oxide electrolysis with blast furnace waste heat utilization, which specifically adopts the following technical solutions:

[0010] An ironmaking system coupling solid oxide electrolysis and blast furnace waste heat utilization, comprising a solid oxide electrolysis system, a hot air system, a heat exchange system and a blast furnace body;

[0011] The blast furnace body is used to reduce ore and smelt pig iron;

[0012] The solid oxide electrolysis system generates hydrogen and oxygen by electrolyzing water under the coupling drive of an external power supply and waste heat of a blast furnace body; the anode outlet of the solid oxide electrolysis system is connected to a hot air system, air enters the hot air system, the cathode outlet is connected to a blast furnace body, and hydrogen is heated by a heat exchanger and sprayed into the blast furnace body;

[0013] The air outlet at the top of the blast furnace body is connected to the hot air system, and the blast furnace gas enters the hot air system from there; the hot air system uses the blast furnace gas as fuel to continuously transport high-temperature hot air to the blast furnace body;

[0014] The slag outlet at the bottom of the blast furnace body is connected to a heat exchanger, and the sensible heat of the slag is recovered by the heat exchanger;

[0015] The heat exchange system connects various heat exchangers and uses the waste heat generated by the blast furnace body to heat the materials at the inlet of the solid oxide electrolytic cell and the hydrogen at the inlet of the blast furnace; the heat exchange system integrates the heat load of each component of the entire system to achieve the cascade recovery and utilization of heat in the electrolytic hydrogen production process and the blast furnace ironmaking process.

[0016] Wherein, the solid oxide electrolysis system comprises an electrolytic cell;

[0017] The cathode inlet of the electrolytic cell is a water inlet, which is sequentially connected to a water pump, a low-temperature heat exchanger and a high-temperature heat exchanger; the water vapor is heated to 800°C by the low-temperature heat exchanger and the high-temperature heat exchanger and enters the electrolytic cell;

[0018] The cathode outlet is connected to the steam heat exchanger at the outlet of the battery stack and the steam-water separator in sequence, and the hydrogen outlet of the steam-water separator is connected to the blast furnace inlet hydrogen heat exchanger of the blast furnace body; the hydrogen is heated to 800℃~1200℃ by the blast furnace inlet hydrogen heat exchanger and injected into the blast furnace body;

[0019] The anode inlet of the electrolytic cell is an air inlet, which is connected to an air compressor and an air heat exchanger in sequence; the air is heated to 800°C by the air heat exchanger and enters the electrolytic cell;

[0020] The anode outlet is connected to the stack outlet air heat exchanger and the hot air system through a tee.

[0021] Wherein, the hot air system comprises a hot air furnace;

[0022] The hot blast furnace is connected to the top air outlet of the blast furnace body through a dust collector and a desulfurizer. The hot blast furnace uses blast furnace gas as fuel, burns and heats the cold air to 1200°C before entering the blast furnace body. A hot blast furnace outlet flue gas heat exchanger is provided at the flue gas outlet of the hot blast furnace.

[0023] Furthermore, a slag heat exchanger and a slag treatment device are provided at the slag outlet at the bottom of the blast furnace body, and the sensible heat of the slag is recovered by the slag heat exchanger.

[0024] The present invention provides an ironmaking method for coupling solid oxide electrolysis with blast furnace waste heat utilization, which is implemented by using the ironmaking system for coupling solid oxide electrolysis with blast furnace waste heat utilization, and comprises the following steps:

[0025] After being pressurized, water and air are passed into a heat exchanger and heated to 800°C, and then respectively passed into the cathode and anode of the solid oxide electrolysis system. An external power supply is supplied to the solid oxide electrolysis system, and water vapor is electrolyzed into hydrogen and oxygen.

[0026] The air at the anode outlet of the solid oxide electrolysis system enters the hot air system, reacts with the blast furnace gas to release heat, and heats the cold air to 1200℃ and is sent into the blast furnace body;

[0027] The hydrogen at the cathode outlet of the solid oxide electrolysis system is heated to 800°C by a heat exchanger and then enters the blast furnace body. The iron ore undergoes a reduction reaction with the hydrogen and coal powder to produce molten iron, blast furnace gas and slag. The blast furnace gas enters the hot air system from the top outlet of the blast furnace body, and the slag enters the heat exchanger from the slag outlet at the bottom of the blast furnace body for cooling.

[0028] The technical solution of the present invention achieves the following beneficial effects:

[0029] (1) The ironmaking system coupled with solid oxide electrolysis and blast furnace waste heat utilization proposed in the present invention integrates the heat loads of various components of the entire ironmaking system through a heat exchange network, realizes the cascade recovery and utilization of waste heat in the solid oxide electrolysis hydrogen production and blast furnace ironmaking process, and improves the comprehensive energy utilization efficiency of electrolytic hydrogen production and blast furnace ironmaking.

[0030] (2) The ironmaking system coupled with solid oxide electrolysis and blast furnace waste heat utilization proposed in the present invention realizes the cascade utilization of heat within the system through a heat exchange network, and uses the heat generated by the blast furnace ironmaking process to preheat the water at the inlet of the electrolytic cell, providing heat compensation for the solid oxide electrolysis hydrogen production process, reducing the power consumption of the hydrogen production process, and reducing the power consumption rate of hydrogen production.

[0031] (3) The ironmaking system coupled with solid oxide electrolysis and blast furnace waste heat utilization proposed in the present invention uses the heat generated by the blast furnace ironmaking process to heat the hydrogen at the blast furnace inlet through a heat exchange network, thereby solving the heat compensation problem of blast furnace hydrogen-rich smelting and ensuring the smelting temperature of the blast furnace.

[0032] (4) The present invention proposes an ironmaking system that couples solid oxide electrolysis with blast furnace waste heat utilization, using hydrogen produced by water electrolysis to replace part of the coke as a reducing agent and exothermic agent, thereby reducing the ironmaking process's dependence on coke and significantly reducing carbon dioxide emissions, which is of great significance to energy conservation and carbon reduction in the ironmaking process. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of the system structure of the present invention.

[0034] Figure 2 Schematic diagram of the heat exchange network of the present invention.

[0035] The specific meanings of the figure numbers in the accompanying drawings are: 1-air compressor, 2-water pump, 3-air heat exchanger, 4-low-temperature heat exchanger, 5-high-temperature heat exchanger, 6-electrolyzer, 7-air heat exchanger at the outlet of the stack, 8-steam heat exchanger at the outlet of the stack, 9-steam-water separator, 10-hydrogen heat exchanger at the inlet of the blast furnace, 11-flue gas heat exchanger at the outlet of the hot blast furnace, 12-hot blast furnace, 13-dust collector, 14-desulfurizer, 15-blast furnace body, 16-slag heat exchanger, 17-slag treatment device, 18-heat exchange system. DETAILED DESCRIPTION

[0036] The present invention proposes an ironmaking system that couples solid oxide electrolysis with blast furnace waste heat utilization, and the present invention is further described below in conjunction with the accompanying drawings.

[0037] Embodiment 1:

[0038] like Figure 1 As shown, this embodiment 1 discloses an ironmaking system that couples solid oxide electrolysis with blast furnace waste heat utilization, including a solid oxide electrolysis system, a hot air system, a heat exchange system 18 and a blast furnace body 15;

[0039] The blast furnace body 15 is used to reduce ore and smelt pig iron;

[0040] The solid oxide electrolysis system comprises an electrolytic cell 6; the cathode inlet of the electrolytic cell 6 is a water inlet, which is sequentially connected to a water pump 2, a low-temperature heat exchanger 4 and a high-temperature heat exchanger 5; the water vapor is heated to 800°C through the low-temperature heat exchanger 4 and the high-temperature heat exchanger 5 and enters the electrolytic cell 6; the cathode outlet is sequentially connected to the stack outlet steam heat exchanger 8 and the steam-water separator 9, and the hydrogen outlet of the steam-water separator 9 is connected to the blast furnace inlet hydrogen heat exchanger 10 of the blast furnace body 15; the hydrogen is heated to 800°C to 1200°C through the blast furnace inlet hydrogen heat exchanger 10 and is sprayed into the blast furnace body 15; the anode inlet of the electrolytic cell 6 is an air inlet, which is sequentially connected to an air compressor 1 and an air heat exchanger 3; the air is heated to 800°C through the air heat exchanger 3 and enters the electrolytic cell 6; the anode outlet is respectively connected to the stack outlet air heat exchanger 7 and the hot air system through a tee.

[0041] The solid oxide electrolysis system, driven by the coupling of an external power supply and the waste heat of the blast furnace body 15, produces hydrogen and oxygen by electrolyzing water; the anode outlet of the solid oxide electrolysis system is connected to the hot air system, and the air enters the hot air system, and the cathode outlet is connected to the blast furnace body 15, and the hydrogen is heated by a heat exchanger and blown into the blast furnace body 15.

[0042] The top air outlet of the blast furnace body 15 is connected to the hot air system, and the blast furnace gas enters the hot air system from there; the hot air system uses the blast furnace gas as fuel to continuously transport high-temperature hot air to the blast furnace body 15; the hot air system includes a hot air furnace 12; the hot air furnace 12 is connected to the top air outlet of the blast furnace body 15 through a dust collector 13 and a desulfurizer 14, and the hot air furnace 12 uses the blast furnace gas as fuel, and burns to heat the cold air to 1200°C before it enters the blast furnace body 15; the smoke outlet of the hot air furnace 12 is provided with a hot air furnace outlet smoke heat exchanger 11.

[0043] A slag heat exchanger 16 and a slag treatment device 17 are provided at the slag outlet at the bottom of the blast furnace body 15 , and the sensible heat of the slag is recovered by the slag heat exchanger 16 .

[0044] The heat exchange system 18 is connected to the above-mentioned heat exchangers, and the waste heat generated by the blast furnace body 15 is used to heat the materials at the inlet of the solid oxide electrolytic cell and the hydrogen at the inlet of the blast furnace; the heat exchange system 18 integrates the heat load of each component of the entire system, and realizes the step-by-step recovery and utilization of heat in the electrolytic hydrogen production process and the blast furnace ironmaking process.

[0045] The specific material flow process is as follows: water is pressurized by water pump 2 and heated by low-temperature heat exchanger 4 and high-temperature heat exchanger 5 to become high-temperature water vapor, which is passed into the cathode of electrolytic cell 6; air is pressurized by air compressor 1 and heated by air heat exchanger 3, which is passed into the anode of electrolytic cell 6; driven by an external power supply, the high-temperature water vapor undergoes an electrochemical reaction in electrolytic cell 6 to produce hydrogen and oxygen, wherein the mixed gas of hydrogen and remaining water vapor at the cathode outlet of electrolytic cell 6 is cooled by steam heat exchanger 8 at the outlet of the stack, and then enters steam-water separator 9 to separate hydrogen and water; the separated pure hydrogen is heated by hydrogen heat exchanger 10 at the inlet of blast furnace and then sent into blast furnace body 15, and water is directly discharged from the system; the oxygen-enriched air at the anode outlet of electrolytic cell 6 is divided into two parts, one part The oxygen-enriched air and blast furnace gas are burned in the hot blast furnace 12, and the heat generated heats the cold air into high-temperature hot air and then enters the blast furnace body 15. The flue gas generated by the combustion is cooled by the flue gas heat exchanger 11 at the hot blast furnace outlet and then discharged from the system. The ore, coal powder and hydrogen undergo a reduction reaction in the blast furnace pump body 15, and the molten iron generated by the reaction flows out from the iron outlet at the bottom of the blast furnace body 15. The slag enters the slag heat exchanger 16 from the slag outlet at the bottom of the blast furnace body 15 for cooling and then is discharged to the slag treatment device 17. The blast furnace gas enters the hot blast furnace 12 from the top air outlet of the blast furnace body 15 after being purified by the dust collector 13 and the desulfurizer 14 for combustion and heating.

[0046] The heat exchange system 18 integrates the heat load of each component of the entire ironmaking system through the utility, and uses cold / hot fluid as the medium to realize the step-by-step recovery and utilization of the heat inside the system, reduce the utility load, and improve the heat integration efficiency. The heat exchange system 18 is connected with the air heat exchanger 3, the low-temperature heat exchanger 4, the high-temperature heat exchanger 5, the air heat exchanger 7 at the outlet of the stack, the steam heat exchanger 8 at the outlet of the stack, the steam-water separator 9, the hydrogen heat exchanger 10 at the inlet of the blast furnace, the flue gas heat exchanger 11 at the outlet of the hot blast furnace, and the slag heat exchanger 16. Among them, there are four cold flows, namely, water at the inlet of the low-temperature heat exchanger 4, steam at the inlet of the high-temperature heat exchanger 5, air at the inlet of the air heat exchanger 3, and hydrogen at the inlet of the blast furnace body 15; there are five hot flows, namely, blast furnace slag, steam and hydrogen mixed gas at the outlet of the cathode of the stack, air at the outlet of the anode of the stack, hot blast furnace flue gas, and hydrogen at the inlet of the blast furnace. The hot utility is the heating furnace, and the cold utility is cooling water.

[0047] Embodiment 2:

[0048] This Example 2 uses the above-mentioned metallurgical system of a solid oxide electrolytic cell coupled with a blast furnace, wherein the blast furnace is a 5000m 3 , a large blast furnace with an annual production capacity of 3.83 million tons. Some parameters of the blast furnace ironmaking process are shown in Table 1.

[0049] Table 1 Parameters of blast furnace ironmaking system

[0050]

[0051]

[0052] like Figure 1 As shown, water is pressurized by a water pump 2 and then heated to 107°C by a low-temperature heat exchanger 4, and then heated to 800°C by a high-temperature heat exchanger 5 and passed into the cathode of an electrolytic cell 6. Air is pressurized by a compressor 1 and then heated to 800°C by an air heat exchanger 3 and passed into the anode of an electrolytic cell 6. High-temperature water vapor undergoes an electrochemical reaction in the electrolytic cell 6 to produce hydrogen and oxygen. A mixed gas (700°C) of hydrogen and remaining water vapor at the cathode outlet of the electrolytic cell 6 is cooled to 120°C by a steam heat exchanger 8 at the outlet of the stack, and enters a steam-water separator 9 to separate hydrogen and water. The separated pure hydrogen (40°C) is heated to 800°C by a hydrogen heat exchanger 10 at the inlet of the blast furnace and sent into the blast furnace body 15, and water is directly discharged from the system. The anode outlet of the electrolytic cell 6 Part of the oxygen-enriched air (700℃) directly enters the hot blast furnace 12, and the other part is cooled to 30℃ through the air heat exchanger 7 at the outlet of the fuel cell stack and discharged; the oxygen-enriched air and blast furnace gas are burned in the hot blast furnace 12, and the heat generated heats the 25℃ cold air into 1200℃ high-temperature hot air, which is then introduced into the blast furnace body 15. The 300℃ flue gas generated by the combustion is cooled to 30℃ through the flue gas heat exchanger 11 at the outlet of the hot blast furnace and discharged; the slag (1500℃) generated in the iron-making process enters the slag heat exchanger 16 from the slag outlet at the bottom of the blast furnace body 15 and is cooled to 30℃ and discharged from the system, and the blast furnace gas (120℃) enters the hot blast furnace 12 from the top outlet of the blast furnace body 15 after being purified by the dust collector 13 and the desulfurizer 14 for combustion and heating.

[0053] Depend on Figure 1 It can be seen that the heat exchange system 18 has four cold streams and five hot streams. Table 2 gives the parameters of the cold and hot streams, where 10°C is the minimum heat exchange temperature difference of the heat exchange network. The heat exchange network process is as follows: Figure 2The slag heat exchanger 16 exchanges heat with the air heat exchanger, the hydrogen heat exchanger 10 at the blast furnace inlet, the low-temperature heat exchanger 4, and the high-temperature heat exchanger 5, respectively, to reduce the slag temperature from 1500°C to 127°C, and then exchanges heat with the air heat exchanger 3, and the slag temperature is reduced to 30°C before being discharged; the steam heat exchanger 8 at the outlet of the stack, the flue gas heat exchanger 11 at the outlet of the hot blast furnace, and the steam-water separator 9 all exchange heat with the low-temperature heat exchanger 4, in which the hydrogen at 700°C at the cathode outlet of the stack is heated by the water vapor. The mixed gas is cooled to 120℃ and then enters the steam-water separator. The hydrogen and water after steam-water separation are cooled to 40℃. The flue gas at the outlet of the hot blast furnace is cooled to 30℃ and then discharged. The air heat exchanger 7 at the outlet of the stack exchanges heat with the cold utility, and the oxygen-rich air at the outlet of the stack anode is cooled to 30℃ and then discharged. The hot utility exchanges heat with the high-temperature heat exchanger 5 and the air heat exchanger 3, and the 107℃ water vapor and 5℃ air are heated to 800℃ and then passed into the stack. When the metallurgical system adopts the heat exchange network, the required heat utility is 127MW, and the cold utility is 0.12MW; when the heat exchange network is not adopted, the required heat utility is 323MW, and the cold utility is 316MW, and the total utility energy saving is 511.88MW.

[0054] Table 2 System hot and cold logistics data

[0055]

[0056]

[0057] The calculation formula for the hydrogen production efficiency of the metallurgical system coupled with the solid oxide electrolytic cell and the blast furnace is as follows:

[0058]

[0059] m H2 is the mass flow rate of hydrogen produced, kg / s; LHV H2 is the lower calorific value of hydrogen, which is 120MJ / kg; W stack is the power of the battery stack, kW; W pump is the power consumption of the pump and compressor, kW; W elec The electric heating power required for the steam generator and heater, kW.

[0060] The calculation formula for the comprehensive energy consumption of the metallurgical system of the solid oxide electrolytic cell coupled with the blast furnace is as follows:

[0061] E=W stack +W pump +W elec +V BFG ·(Q BFG +Q DW )

[0062] VBFG is the flow rate of blast furnace gas entering the hot blast stove, m 3 / s,Q BFG is the sensible heat of blast furnace gas, kJ / m 3 , Q DW is the low calorific value of blast furnace gas, kJ / m 3 .

[0063] The calculation formula for the comprehensive energy efficiency of the metallurgical system of the solid oxide electrolytic cell coupled with the blast furnace is as follows:

[0064]

[0065] V hot is the flow rate of hot air entering the blast furnace, m 3 / s,C hot is the specific heat of hot air, kJ / m 3 , C cold is the specific heat of cold air, kJ / m 3 , t hot is the temperature of hot air, °C, t cold is the temperature of cold wind, ℃.

[0066] According to the parameters in Table 1, when the heat exchange network is not used, the hydrogen production efficiency of the metallurgical system of the solid oxide electrolytic cell coupled with the blast furnace is 44.58%, the comprehensive energy consumption is 1096.30MW, and the comprehensive energy efficiency is 55.09%; when the heat exchange network is used, the hydrogen production efficiency of the system is 62.96%, the comprehensive energy consumption is 857.54MW, and the comprehensive energy efficiency is 70.43%. The heat exchange network realizes the cascade recovery and utilization of the internal heat of the system, reduces the energy consumption of the system, and significantly improves the hydrogen production efficiency and the comprehensive energy efficiency of the system.

[0067] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An ironmaking system coupling solid oxide electrolysis and blast furnace waste heat utilization, characterized in that: It comprises a solid oxide electrolysis system, a hot air system, a heat exchange system (18) and a blast furnace body (15); The blast furnace body (15) is used to reduce ore and smelt pig iron; The solid oxide electrolysis system generates hydrogen and oxygen by electrolyzing water under the coupling drive of an external power supply and waste heat of a blast furnace body (15); the anode outlet of the solid oxide electrolysis system is connected to a hot air system, air enters the hot air system, and the cathode outlet is connected to the blast furnace body (15), and hydrogen is heated by a heat exchanger and sprayed into the blast furnace body (15); The top air outlet of the blast furnace body (15) is connected to a hot air system, and blast furnace gas enters the hot air system from the outlet; the hot air system uses blast furnace gas as fuel to continuously deliver high-temperature hot air to the blast furnace body (15); The slag outlet at the bottom of the blast furnace body (15) is connected to a heat exchanger, and the sensible heat of the slag is recovered by the heat exchanger; The heat exchange system (18) is connected to each heat exchanger to use the waste heat generated by the blast furnace body (15) to heat the inlet material of the solid oxide electrolytic cell and the inlet hydrogen of the blast furnace; the heat exchange system (18) integrates the heat load of each component of the entire system to achieve the step-by-step recovery and utilization of heat in the electrolytic hydrogen production process and the blast furnace ironmaking process.

2. The ironmaking system for coupling solid oxide electrolysis with blast furnace waste heat utilization according to claim 1, characterized in that: The solid oxide electrolysis system comprises an electrolytic cell (6); The cathode inlet of the electrolytic cell (6) is a water inlet, which is sequentially connected to a water pump (2), a low-temperature heat exchanger (4) and a high-temperature heat exchanger (5); water vapor is heated to 800° C. by the low-temperature heat exchanger (4) and the high-temperature heat exchanger (5) and enters the electrolytic cell (6); The cathode outlet is connected to the stack outlet steam heat exchanger (8) and the steam-water separator (9) in sequence, and the hydrogen outlet of the steam-water separator (9) is connected to the blast furnace inlet hydrogen heat exchanger (10) of the blast furnace body (15); the hydrogen is heated to 800° C. to 1200° C. through the blast furnace inlet hydrogen heat exchanger (10) and then injected into the blast furnace body (15); The anode inlet of the electrolytic cell (6) is an air inlet, which is sequentially connected to an air compressor (1) and an air heat exchanger (3); the air is heated to 800° C. through the air heat exchanger (3) and then enters the electrolytic cell (6); The anode outlet is connected to the stack outlet air heat exchanger (7) and the hot air system through a tee.

3. The ironmaking system coupling solid oxide electrolysis and blast furnace waste heat utilization according to claim 1, characterized in that: The hot air system comprises a hot air furnace (12); The hot blast furnace (12) is connected to the top air outlet of the blast furnace body (15) through a dust collector (13) and a desulfurizer (14). The hot blast furnace (12) uses blast furnace gas as fuel, burns and supplies heat to heat the cold air to 1200° C. before entering the blast furnace body (15). The smoke outlet of the hot blast furnace (12) is provided with a hot blast furnace outlet smoke heat exchanger (11).

4. The ironmaking system for coupling solid oxide electrolysis with blast furnace waste heat utilization according to claim 1, characterized in that: A slag heat exchanger (16) and a slag treatment device (17) are provided at the slag outlet at the bottom of the blast furnace body (15), and the sensible heat of the slag is recovered by the slag heat exchanger (16).

5. An ironmaking method coupling solid oxide electrolysis with blast furnace waste heat utilization, characterized in that: The method is implemented by using an ironmaking system coupling solid oxide electrolysis and blast furnace waste heat utilization as described in any one of claims 1 to 4, comprising the following steps: After being pressurized, water and air are passed into a heat exchanger and heated to 800°C, and then respectively passed into the cathode and anode of the solid oxide electrolysis system. An external power supply is supplied to the solid oxide electrolysis system, and water vapor is electrolyzed into hydrogen and oxygen. The air at the anode outlet of the solid oxide electrolysis system enters the hot air system, undergoes combustion reaction with blast furnace gas to release heat, and heats the cold air to 1200°C and is sent to the blast furnace body (15); The hydrogen at the cathode outlet of the solid oxide electrolysis system is heated to 800°C by a heat exchanger and then enters the blast furnace body (15). The iron ore reacts with the hydrogen and coal powder to produce molten iron, blast furnace gas and slag. The blast furnace gas enters the hot air system from the top air outlet of the blast furnace body (15), and the slag enters the heat exchanger from the slag outlet at the bottom of the blast furnace body (15) for cooling.

Images