Low-carbon and efficient hot blast stove clean combustion system

Abstract

The utility model discloses a low-carbon efficient hot blast stove clean combustion system which comprises a coal gas desulfurization device, a CO pressure swing adsorption device, a first plate heat exchanger, a second plate heat exchanger, a hot blast stove, pulverized coal drying equipment, a first bag-type dust collector, a second bag-type dust collector, a cooler, a dehydrator, a first compressor and an air blower. The blast furnace gas pipeline is sequentially communicated with the gas desulfurization device and the CO pressure swing adsorption device; an N2-rich gas outlet of the CO pressure swing adsorption device is communicated with a second bag-type dust collector through an N2-rich gas pipeline; a CO-rich gas outlet of the CO pressure swing adsorption device is communicated with a heated medium inlet of the first plate heat exchanger through a CO-rich gas pipeline, and a heated medium outlet of the first plate heat exchanger is communicated with a combustion gas inlet of the hot blast stove. According to the system, the combustion efficiency of the hot blast stove can be improved, the generation of NO and NO2 pollutants is reduced, the emission of SO2 pollutants is reduced, and meanwhile, N2-rich tail gas subjected to CO pressure swing adsorption and CO2 generated by combustion of the hot blast stove are recycled.

Description

Technical Field

[0001] This utility model relates to a blast furnace system, and more particularly to a low-carbon, high-efficiency clean combustion system for a hot blast stove. Background Technology

[0002] Hot blast stoves are auxiliary equipment used to supply high-temperature hot blast to blast furnaces. The hot blast temperature reaches over 1200℃, and each blast furnace is typically equipped with 3 to 4 hot blast stoves. These stoves primarily use blast furnace gas as fuel, which has a low CO content of approximately 25%, with the remaining CO2 at approximately 15% and N2 at approximately 55%. Air is used for combustion, with an O2 content of 21% and an N2 content of 79%. The flue gas temperature of the hot blast stove is approximately 250–350℃. The CO2 and N2 in the blast furnace gas and combustion air do not participate in combustion and are emitted with the flue gas, carrying away a large amount of heat. This not only wastes heat and reduces combustion efficiency but also emits a large amount of greenhouse gases. Furthermore, blast furnace gas contains sulfides, which produce SO2 during combustion. Simultaneously, due to the high combustion temperature (over 1300℃), N2 and O2 react to produce NO and NO2. The generated SO2, NO, and NO2 are emitted with the flue gas, causing environmental pollution. Utility Model Content

[0003] The technical problem to be solved by this utility model is to provide an energy-saving, environmentally friendly, low-carbon, and high-efficiency clean combustion system for hot air furnaces.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows: It includes a gas desulfurization device, a CO pressure swing adsorption device, a No. 1 plate heat exchanger, a No. 2 plate heat exchanger, a hot blast stove, pulverized coal drying equipment, a No. 1 bag filter, a No. 2 bag filter, a cooler, a dehydrator, a No. 1 compressor, and a blower; the blast furnace gas pipeline is sequentially connected to the gas desulfurization device and the CO pressure swing adsorption device; the N2-rich gas outlet of the CO pressure swing adsorption device is connected to the No. 2 bag filter through an N2-rich gas pipeline; the CO-rich gas outlet of the CO pressure swing adsorption device is connected to the inlet of the heated medium of the No. 1 plate heat exchanger through a CO-rich gas pipeline, and the No. 1 plate... The outlet of the heated medium of the plate heat exchanger is connected to the combustion gas inlet of the hot blast stove; the outlet of the heated medium of the No. 2 plate heat exchanger is connected to the O2 pipeline, and the outlet of the heated medium is connected to the combustion gas inlet of the hot blast stove; the high-temperature flue gas outlet of the hot blast stove is connected to the heating medium inlets of the No. 1 and No. 2 plate heat exchangers respectively; the heating medium outlets of the No. 1 and No. 2 plate heat exchangers are connected to the pulverized coal drying equipment, and the flue gas outlet of the pulverized coal drying equipment is connected to the No. 1 bag filter; the inlet of the blower is connected to the O2 pipeline and the cold air pipeline, the outlet is connected to the cold air inlet of the hot blast stove, and the hot air outlet of the hot blast stove is connected to the blast furnace tuyeres.

[0005] Furthermore, a No. 2 compressor is also provided; the inlet of the No. 2 compressor is connected to the outlet of the No. 2 bag filter, and the outlet of the No. 2 compressor is connected to the purging, replacement and / or sealing device of the blast furnace ironmaking system.

[0006] Furthermore, a cooler, a dehydrator, and a No. 1 compressor are also provided; the outlet of the No. 1 bag filter is connected in sequence to the cooler, the dehydrator, and the No. 1 compressor, and the outlet of the No. 1 compressor is connected to the pulverized coal treatment system.

[0007] Furthermore, the hot air furnace is provided in three units and arranged in parallel; the outlet of the blower is connected to the cold air inlet of each of the three hot air furnaces through a cold air main pipe.

[0008] Furthermore, it also includes an ejector; the hot air outlets of the hot air furnace are all connected to a preheating main pipe; the inlet of the ejector is connected to the outlet of the blower, the outlet is connected to the cold air main pipe, and the exhaust port is connected to the preheating main pipe.

[0009] The beneficial effects of adopting the above technical solution are as follows: This utility model uses technologies such as CO pressure swing adsorption, pure oxygen combustion, and waste heat recovery to improve the combustion efficiency of the hot blast stove and reduce the generation of NO and NO2 pollutants. Combined with blast furnace gas desulfurization technology, it reduces SO2 pollutant emissions. At the same time, it recovers and utilizes the N2-rich tail gas from CO pressure swing adsorption and the CO2 generated by the combustion of the hot blast stove; it can further improve the clean production level of the blast furnace hot blast stove system.

[0010] This invention increases the CO content in blast furnace gas through pressure swing adsorption (PSA), thereby improving the combustion efficiency of the blast furnace hot blast stove. Simultaneously, it removes sulfur-containing components and N2 from the blast furnace gas and uses pure oxygen for combustion, thus significantly reducing the generation of sulfur oxides and nitrogen oxides during combustion. The tail gas after PSA is enriched with N2 and can be used for purging, replacement, and sealing in the blast furnace ironmaking process, reducing nitrogen consumption. The main component of the hot blast stove flue gas is CO2. After cooling and pressurization, it replaces nitrogen in pulverized coal conveying and injection, reducing the theoretical combustion temperature at the tuyeres, increasing the oxygen enrichment rate and pulverized coal injection rate in the blast furnace, thus increasing blast furnace production. It can also generate CO, improving the indirect reduction degree of the blast furnace, the gas volume, and the calorific value of the gas. Attached Figure Description

[0011] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0012] Figure 1 This is a schematic diagram of the system structure of this utility model.

[0013] In the diagram: 1. Blast furnace gas pipeline; 2. O2 pipeline; 3. CO-rich gas pipeline; 4. N2-rich gas pipeline; 5. Cold air pipeline; A. Gas desulfurization device; B. CO pressure swing adsorption device; C1. Plate heat exchanger #1; C2. Plate heat exchanger #2; D1. Hot blast stove #1; D2. Hot blast stove #2; D3. Ejector; F. Blower; G. Cold air main pipe; H. Preheating main pipe; I. Hot air main pipe; J. Flue gas main pipe; K. Pulverized coal drying equipment; L1. Bag filter; L2. Bag filter; M. Cooler; N. Dehydrator; P1. Compressor #1; P2. Compressor #2. Detailed Implementation

[0014] Figure 1 As shown, this low-carbon, high-efficiency hot blast stove clean combustion system includes a gas desulfurization device A, a CO pressure swing adsorption device B, a #1 plate heat exchanger C1, a #2 plate heat exchanger C2, a hot blast stove, a pulverized coal drying device K, a #1 bag filter L1, a #2 bag filter L2, a cooler M, a dehydrator N, a #1 compressor P1, a #2 compressor P2, a blower F, a cooler M, a dehydrator N, and a #1 compressor P1. The blast furnace gas pipeline 1 connects to the inlet of the gas desulfurization device A, and the outlet of the gas desulfurization device A connects to the inlet of the CO pressure swing adsorption device B. The N2-rich gas outlet of the CO pressure swing adsorption device B connects to the #2 bag filter L2 via an N2-rich gas pipeline 4; the inlet of the #2 compressor P2 connects to the outlet of the #2 bag filter L2, and the outlet of the #2 compressor (P2) connects to the purging, replacement, and / or sealing devices of the blast furnace ironmaking system. With this structure, the blast furnace gas first undergoes desulfurization in the gas desulfurization device A, and then is divided into CO-rich gas and N2-rich gas by the CO pressure swing adsorption device B. The N2-rich gas is discharged through the tail gas pipeline, and after being dusted by the No. 2 bag filter L2, it is pressurized to 0.8MPa by the No. 2 compressor P2 and used for purging, replacement, sealing and other parts of the blast furnace ironmaking system that can replace N2.

[0015] Figure 1As shown, in this low-carbon, high-efficiency clean combustion system for a hot blast stove, the CO-rich gas outlet of the CO pressure swing adsorption device B is connected to the inlet of the heated medium of plate heat exchanger C1 (No. 1) via CO-rich gas pipeline 3. The outlet of the heated medium of plate heat exchanger C1 is connected to the combustion gas inlet of the hot blast stove. The inlet of the heated medium of plate heat exchanger C2 (No. 2) is connected to O2 pipeline 2, and the outlet of the heated medium is connected to the combustion gas inlet of the hot blast stove. The high-temperature flue gas outlet of the hot blast stove is connected to the heating medium inlets of plate heat exchangers C1 and C2, respectively. The heating medium outlets of plate heat exchangers C1 and C2 are connected to pulverized coal drying equipment K, and the flue gas outlet of pulverized coal drying equipment K is connected to bag filter L1. The outlet of bag filter L1 is connected sequentially to cooler M, dehydrator N, and compressor P1, and the outlet of compressor P1 is connected to the pulverized coal treatment system. With this structure, the CO-rich gas separated from the CO pressure swing adsorption device B is heated to over 200°C via plate heat exchanger C1 (#1) and O2 is heated to over 200°C via plate heat exchanger C2 (#2). The gas is then introduced from the top of the hot blast stove for combustion, where heat is accumulated. The flue gas is discharged from the bottom of the hot blast stove. The flue gas temperature is approximately 400–450°C. It is introduced into plate heat exchangers C1 and C2 to raise the temperature of the CO-rich gas and O2, reducing the flue gas temperature to around 150°C. It then enters the pulverized coal drying device, where the sensible heat of the flue gas evaporates the moisture in the pulverized coal, simultaneously lowering the flue gas temperature to below 100°C. After passing through bag filter L1 (#1), the flue gas temperature is reduced to ambient temperature by cooler M, then further reduced by dehydrator N, and finally pressurized to 1.6 MPa by compressor P1 (#1) for pulverized coal fluidization, pressure stabilization, conveying, and injection.

[0016] Figure 1As shown, this low-carbon, high-efficiency clean combustion system for hot blast stoves includes three hot blast stoves arranged in parallel: hot blast stove #1 (D1), hot blast stove #2 (D2), and hot blast stove #3 (D3). The outlet of the heated medium of plate heat exchanger #1 (C1) and plate heat exchanger #2 (C2) are both connected to the combustion gas inlets of the three hot blast stoves. The high-temperature flue gas outlets of the three hot blast stoves are connected to the heating medium inlets of plate heat exchangers #1 (C1) and #2 (C2) respectively via the flue gas main pipe J. The inlet of the blower F is connected to O2 pipe 2 and cold air pipe 5, and the outlet of the blower F is connected to the cold air inlets of the three hot blast stoves via the cold air main pipe G. The hot air outlet of the hot blast stove is connected to the blast furnace tuyeres via the hot air main pipe I. It also includes ejectors E, and the hot air outlets of all three hot blast stoves are connected to a preheating main pipe H; the inlet of ejector E is connected to the outlet of blower F, the outlet is connected to the cold air main pipe G, and the exhaust port is connected to the preheating main pipe H. With this structure, the three hot blast stoves perform combustion, air supply, and preheating cycles respectively, that is, the three hot blast stoves simultaneously perform combustion, air supply, and preheating operations respectively. After the stoves are turned over, the three hot blast stoves switch operating states; the hot blast stove that performs combustion operation is called a combustion hot blast stove, the hot blast stove that performs air supply operation is called an air supply hot blast stove, and the hot blast stove that performs preheating operation is called a preheating hot blast stove. The combustion hot blast stove is fed with the aforementioned CO-rich gas and O2 for combustion at the top and exhausts flue gas at the bottom, with heat accumulating inside the combustion hot blast stove. The function of the forced blast stove and the preheating hot blast stove is to heat the cold air and supply hot blast to the blast furnace. The cold air is enriched with oxygen and then enters the blower F to be pressurized to 0.5 MPa. It then enters the cold air main pipe G. The cold air is input from the bottom of the preheating hot blast stove and undergoes preliminary preheating inside the hot blast stove at a temperature of about 600-900°C. It is then discharged from the top and enters the preheating main pipe H. Through the preheating main pipe H, it is input from the bottom of the forced blast furnace and further heated to above 1300°C. It is then discharged from the top and enters the hot blast main pipe I to be delivered to the blast furnace tuyeres.

[0017] When the combustion hot blast stove and preheating hot blast stove reach the specified temperature or the specified air supply time, combustion is stopped and the furnace is turned over. During the furnace turning over process, cold air is introduced into the air supply hot blast stove through valve operation. After being heated, the hot air is directly delivered to the blast furnace. Then, through the ejector, the cold air from the blower outlet is used to eject the large amount of high-temperature, high-pressure oxygen-enriched hot air remaining in the preheating hot blast stove for reuse. After the recovery is completed, the preheating hot blast stove introduces CO-rich gas and O2 to start combustion and heat storage, while the hot air from the forced blast stove enters the preheating main pipe H from the top of the furnace, enters the combustion hot blast stove from the bottom through the preheating main pipe H, and is delivered to the blast furnace tuyeres from the top through the hot blast main pipe I, thus completing the furnace switching operation. The combustion hot blast stove is converted into a forced blast stove, the forced blast stove is converted into a preheating hot blast stove, and the preheating hot blast stove is converted into a combustion hot blast stove. For example, hot blast stove D1 performs combustion, hot blast stove D2 performs forced blast, and hot blast stove D3 performs preheating. When hot blast stove D1 and hot blast stove D3 reach the specified temperature or the specified forced blast time, combustion is stopped and the furnace switching operation is performed. After the furnace switching operation is completed, hot blast stove D1 is converted into a forced blast stove, hot blast stove D2 is converted into a preheating hot blast stove, and hot blast stove D3 is converted into a combustion hot blast stove.

Claims

1. A low-carbon, high-efficiency clean combustion system for a hot blast stove, characterized in that: It includes a gas desulfurization unit (A), a CO pressure swing adsorption unit (B), a No. 1 plate heat exchanger (C1), a No. 2 plate heat exchanger (C2), a hot blast stove, a pulverized coal drying unit (K), a No. 1 bag filter (L1), a No. 2 bag filter (L2), a cooler (M), a dehydrator (N), a No. 1 compressor (P1), and a blower (F); the blast furnace gas pipeline (1) is connected in sequence to the gas desulfurization unit (A) and the CO pressure swing adsorption unit (B); the N2-rich gas outlet of the CO pressure swing adsorption unit (B) is connected to the No. 2 bag filter (L2) through the N2-rich gas pipeline (4); the CO-rich gas outlet of the CO pressure swing adsorption unit (B) is connected to the inlet of the heated medium of the No. 1 plate heat exchanger (C1) through the CO-rich gas pipeline (3), and the No. 1 plate heat exchanger... The outlet of the heated medium of the heat exchanger (C1) is connected to the combustion gas inlet of the hot blast stove; the inlet of the heated medium of the #2 plate heat exchanger (C2) is connected to the O2 pipeline (2), and the outlet of the heated medium is connected to the combustion gas inlet of the hot blast stove; the high-temperature flue gas outlet of the hot blast stove is connected to the heating medium inlets of the #1 plate heat exchanger (C1) and the #2 plate heat exchanger (C2) respectively; the outlets of the heating medium of the #1 plate heat exchanger (C1) and the #2 plate heat exchanger (C2) are connected to the pulverized coal drying equipment (K), and the flue gas outlet of the pulverized coal drying equipment (K) is connected to the #1 bag filter (L1); the inlet of the blower (F) is connected to the O2 pipeline (2) and the cold air pipeline (5), the outlet is connected to the cold air inlet of the hot blast stove, and the hot air outlet of the hot blast stove is connected to the blast furnace tuyeres.

2. The low-carbon, high-efficiency clean combustion system for a hot blast stove according to claim 1, characterized in that: It is also equipped with a No. 2 compressor (P2); the inlet of the No. 2 compressor (P2) is connected to the outlet of the No. 2 bag filter (L2), and the outlet of the No. 2 compressor (P2) is connected to the purging, replacement and / or sealing device of the blast furnace ironmaking system.

3. The low-carbon, high-efficiency clean combustion system for a hot blast stove according to claim 1, characterized in that: It is also equipped with a cooler (M), a dehydrator (N) and a No. 1 compressor (P1); the outlet of the No. 1 bag filter (L1) is connected in sequence to the cooler (M), the dehydrator (N) and the No. 1 compressor (P1), and the outlet of the No. 1 compressor (P1) is connected to the pulverized coal treatment system.

4. A low-carbon, high-efficiency clean combustion system for a hot blast stove according to claim 1, 2, or 3, characterized in that: The hot blast furnace is provided in three units and is arranged in parallel; the outlet of the blower (F) is connected to the cold air inlet of the three hot blast furnaces through the cold air main pipe (G).

5. The low-carbon, high-efficiency clean combustion system for a hot blast stove according to claim 4, characterized in that: It also includes an ejector (E); the hot air outlets of the hot air furnace are all connected to a preheating main pipe (H); the inlet of the ejector (E) is connected to the outlet of the blower (F), the outlet is connected to the cold air main pipe (G), and the exhaust port is connected to the preheating main pipe (H).

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