A blast furnace stable injection of coke oven gas process and injection system

Abstract

The present application relates to a kind of blast furnace stable injection of coke oven gas process and injection system, including sequentially through gas pipeline connection's rough deoiling de-naphthalene device, gas compressor, gas deep purification device, buffer tank, preheating device, fire arrestor, injection device;The fire arrestor is connected with the gas pipeline connection oxygen enrichment pipeline of injection device.Said rough deoiling de-naphthalene device, gas compressor and gas deep purification device are at least one work one spare two sets.Convenient overhaul system can be continuously operated.Compared with prior art, the beneficial effects of the present application are: the process of the present application can overcome the technical problems such as injection system easy to block after injection of coke oven gas, coal combustion is not sufficient, coke reduction effect is not obvious, etc., realize the requirement of long-term stable injection of coke oven gas smelting of blast furnace, achieve the final goal of reducing carbon fuel consumption, greatly reducing blast furnace fuel ratio and CO2 emission, truly realizing green and low-carbon smelting of blast furnace.

Description

Technical Field

[0001] This invention belongs to the field of iron and steel metallurgy, and particularly relates to a process and injection system for stable injection of coke oven gas into a blast furnace. Background Technology

[0002] In response to global warming, major countries around the world signed the Paris Agreement in 2015. This agreement primarily mandates member countries to reduce carbon emissions. In 2019, my country's total carbon dioxide emissions exceeded 10 billion tons, with the steel industry accounting for over 16% of the national total. Under the backdrop of stringent global resource and environmental policies, the steel industry faces immense environmental pressure. Effectively reducing carbon intensity has become a top priority in carbon reduction plans. Low-carbon and green development is the future direction of the steel industry. Hydrogen metallurgy, which utilizes hydrogen in steel manufacturing, is a transformative technology and one of the effective ways for the steel industry to optimize its energy structure, processes, and industrial structure, ultimately achieving low-carbon, green, and sustainable development.

[0003] Beginning in the 1960s, domestic and international steel companies began exploring the production technology of injecting coke oven gas into blast furnaces. In the early 1980s, the Soviet Union had completed experimental research on injecting coke oven gas into several blast furnaces and mastered the technique of injecting 1.8–2.2 m³ of gas. 3 Coke oven gas replacement 1m 3 Natural gas refining technology. In the mid-1980s, the No. 2 blast furnace at the Solme plant in France began injecting coke oven gas, with an injection rate reaching 21,000 m³. 3 The replacement ratio of injected coke oven gas to coke is 0.9 kg / kg / h, which translates to a volume replacement ratio of approximately 0.378 kg / m³. 3 Starting in the second quarter of 2002, the LINZ plant of Voestalpine implemented coke oven gas injection as a substitute for heavy oil in BF5 and BF6 boilers, using a dual-nozzle injection system. The injection rate reached 50 kg / t of iron, equivalent to a volumetric injection rate of 130 m³ / t of iron. 3 Heavy oil consumption decreased from 70 kg / t to 15 kg / t. The two blast furnaces at U.S. Steel's Mon Valley plant have been injecting coke oven gas since 1994. In 2005, the total injection volume was 141,600 tons, with an injection rate of approximately 65 m³ / t. 3 / t. The plant previously reported that after injecting coke oven gas, it reduced the daily blast furnace combustion volume, eliminated venting of coke oven gas, reduced energy waste and energy costs, resulting in net annual savings exceeding $6.1 million. To enable coke oven gas injection, the company implemented necessary purification treatments for the coke oven gas and made necessary modifications to the blast furnace tuyeres.

[0004] In the 1960s, there were also some researches on injecting coke oven gas into small blast furnaces in Benxi Steel and Xuzhou Steel, and some achievements were made. The coke oven gas injection rate in Benxi Steel was 81.6 m3 / t, which reduced the coke rate by 60 kg / t and increased the output by 10%-11%, equivalent to 0.735 kg / m 3 of displacement. Although the effect of injecting coke oven gas needs to be further studied, it has proved the feasibility of injecting coke oven gas.

[0005] In 2009, Jinan Iron and Steel Group Co., Ltd. officially launched the research project of injecting coke oven gas into blast furnace. By March 2011, four industrial tests were conducted on No. 4 blast furnace (350 m 3 ). The results of the industrial tests showed that if the coke oven gas resources of an enterprise are excessive, the injection of coke oven gas into blast furnace can produce certain economic benefits and reduce CO2 emissions. As long as the process route of injecting coke oven gas into blast furnace is correct and the method is appropriate, the safety of injecting coke oven gas can be completely guaranteed. When the injection rate of No. 4 blast furnace was 62.51 m 3 / t, the coke rate was reduced by 5.28 kg / t, the coal rate was reduced by 40.63 kg / t, the cost per ton of iron was reduced by 10.42 yuan / t, and the CO2 emissions were reduced by 75 kg / t.

[0006] In 2010, Cheng Steel Ironworks of Hebei Iron and Steel Group conducted an industrial test of injecting coke oven gas into No. 6 blast furnace. During the test, the fuel ratio of the blast furnace increased instead of decreasing, mainly due to the insufficient combustion of coal powder mixed with the injection port, which caused the slag and iron to stick together and the iron loss of the blast furnace to increase. The next step is to match the upper and lower system, optimize the injection method, and adjust the fuel structure of the injection port to eliminate the problems of poor furnace operation and increased iron loss after injecting coke oven gas.

[0007] From 2012 to 2014, Ansteel Group conducted four industrial tests of injecting coke oven gas into No. 1 blast furnace of Lushan Branch. During the test, the injection rate gradually increased from 6000 m 3 / h to 12000 m 3 / h, the injection rate per ton of iron increased from 16 m 3 to 38 m 3 , the coke oven gas compression system and injection system were safe and reliable, meeting the basic requirements of blast furnace injection. The blast furnace reacted well during the injection of coke oven gas, and the technical indicators of the blast furnace, such as fuel ratio, were significantly improved. CO2 emissions were reduced by 55 kg / t (3.6%), and the fuel ratio of the blast furnace was reduced by 18 kg / t (3.6%).

[0008] Although some domestic steel enterprises have explored the technology of blast furnace injection of coke oven gas smelting earlier, there have been reports of similar enterprises successfully injecting coke oven gas smelting in recent years, but there is still a big gap between successful injection and long-term stable injection. In fact, at present, no domestic steel enterprise has successfully realized long-term stable injection of coke oven gas smelting technology. The main reasons are as follows: 1. The enthusiasm of various enterprises to explore hydrogen-rich blast furnace injection is high, so they have built blast furnace injection of coke oven gas facilities, but most of them have been abandoned by blast furnace operators because the project is implemented hastily and the impact of coke oven gas on the injection system is not fully considered, resulting in the inability of the injection system to operate stably for a long time; 2. The impurities such as tar, naphthalene, benzene and sulfides in coke oven gas are prone to precipitate and enrich in the injection system pipeline and lance under high pressure, thereby blocking the injection system, and the fluidized material also causes strong corrosion of the injection pipeline, which is not conducive to the long-term stable operation of the injection system; 3. Most enterprises do not have systematic research on the impact of blast furnace injection of coke oven gas on the heat of the blast furnace hearth and the impact of gas flow distribution, and do not fully understand the smelting rules after injecting coke oven gas, which leads to unsatisfactory smelting effect after injecting coke oven gas into the blast furnace; 4. The design and transformation scheme of the injection lance and tuyere, the end equipment of the coke oven gas injection, of some enterprises is not mature, resulting in frequent phenomena of coke coking and tuyere damage when injecting coke oven gas, which also causes the fact that stable injection of coke oven gas into the blast furnace cannot be realized.

[0009] Therefore, in order to overcome the above technical problems, the present application proposes relevant innovative measures from the main links of coke oven gas purification, injection system transformation, blast furnace injection of coke oven gas smelting technology, etc., overcomes the relevant technical difficulties, realizes the requirements of long-term stable injection of coke oven gas into the blast furnace, and achieves the final goal of reducing carbon fuel consumption, greatly reducing CO2 emissions, and truly realizing low-carbon green smelting of the blast furnace. SUMMARY

[0010] In view of the technical problems of blast furnace injection of coke oven gas smelting technology, such as easy blocking of the injection system, coke coking of the lance, damage of the tuyere, and non-obvious injection effect, which lead to the phenomenon that the blast furnace cannot realize long-term stable injection of coke oven gas, the present application proposes a blast furnace stable injection of coke oven gas process and injection system from the main links of coke oven gas purification, injection system transformation, blast furnace injection of coke oven gas smelting technology, etc., relevant innovative measures, and overcomes the relevant technical difficulties, realizes the requirements of long-term stable injection of coke oven gas into the blast furnace, and achieves the final goal of reducing carbon fuel consumption, greatly reducing CO2 emissions, and truly realizing low-carbon green smelting of the blast furnace.

[0011] In order to achieve the above purpose, the present application adopts the following technical scheme:

[0012] A blast furnace stable injection of coke oven gas process, comprising:

[0013] 1) The preliminary purified coke oven gas from the gas holder is treated by the crude oil removal and naphthalene removal device, and then enters the gas compressor, and is pressurized to the injection pressure by the compressor and sent to the deep gas purification device. The crude oil removal and naphthalene removal device uses activated carbon microspheres as the filler;

[0014] 2) The coke oven gas from the gas compressor first enters the oil removal tank, which uses activated carbon fiber as the filler, and the naphthalene and tar contents in the gas are reduced to 1 mg / Nm 3 The following is sent to the dry crude desulfurization device for crude desulfurization, and the crude desulfurization uses alkali-modified raw carbon adsorbent SQ105 to remove H2S in the gas to ≤1 mg / Nm 3 ;

[0015] 3) The coke oven gas after crude desulfurization enters the TSA I benzene removal process at a temperature of ≤40℃, and the impurity components are removed so that the benzene content in the coke oven gas is ≤10 mg / Nm 3 : The TSA process uses a full dry purification process, and after the adsorbent is saturated, it is regenerated by heating the purified coke oven gas, and then cooled and used in the next cycle. The TSA I process uses activated carbon microspheres as the adsorbent, and then enters the TSA II benzene removal process, and the impurity components are removed so that the benzene content in the final purified gas is ≤1 mg / Nm 3 , the tar content is ≤0.1 mg / Nm 3 , and the naphthalene content is ≤0.1 mg / Nm 3 ; After the adsorbent is saturated, it is regenerated by heating the purified coke oven gas, and then cooled and used in the next cycle. The TSA II process uses activated carbon adsorbent SQ105 as the adsorbent;

[0016] 4) The purified coke oven gas is sent to the buffer tank and then enters the preheating device, and is preheated to 80-100℃ in the preheating device;

[0017] 5) Oxygen is introduced into the gas pipeline after the flame arrestor, so that the oxygen and the purified coke oven gas enter the coke oven gas surrounding pipe together, and then enter the inner pipe of the double-layer sleeve type coal gun through the coke oven gas branch pipe, and the pulverized coal enters the outer pipe of the double-layer sleeve type coal gun through the pulverized coal distributor; This can ensure that the pulverized coal contacts the oxygen in the blast before the tuyere end, so as to achieve more complete combustion and reduce the amount of unburned pulverized coal; The oxygen pipeline after the flame arrestor can increase the combustion rate of the pulverized coal and reduce the amount of unburned pulverized coal; At the same time, oxygen and coke oven gas enter the blast furnace, which can make the hydrocarbons such as CH4 in the coke oven gas fully burn; The coke oven gas, oxygen and pulverized coal are injected into the blast furnace hearth at the same time.

[0018] The oxygen content accounts for ≤5% of the total gas content of oxygen and coke oven gas.

[0019] A blast furnace gas injection system for a stable blast furnace gas injection process includes a coarse oil and naphthalene removal device, a gas compressor, a deep gas purification device, a buffer tank, a preheating device, a flame arrester, and an injection device, which are connected in sequence through a gas pipeline; the gas pipeline connected to the flame arrester and the injection device is connected to an oxygen-enriched pipeline.

[0020] The aforementioned crude oil and naphthalene removal unit, gas compressor, and deep gas purification unit are provided in at least two sets, one operational and one standby, to facilitate continuous operation of the system during maintenance.

[0021] The deep gas purification device includes an oil removal tank, a coarse desulfurization device, a TSAI benzene removal process, and a TSAⅡ benzene removal process, which are connected in sequence through a gas pipeline.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] By adopting the process of this invention, we can overcome technical problems such as easy blockage of the post-injection system of coke oven gas, incomplete combustion of pulverized coal, and insignificant coke reduction effect. This will enable us to meet the requirements of long-term stable injection of coke oven gas for blast furnace smelting, reduce carbonaceous fuel consumption, significantly reduce blast furnace fuel ratio and CO2 emissions, and truly achieve the ultimate goal of green and low-carbon blast furnace smelting. Attached Figure Description

[0024] Figure 1 It is a process diagram for the invention of a stable coke oven gas injection system.

[0025] In the diagram: 1-coarse deoiling and denaphthalene removal unit, 2-gas compressor, 3-gas deep purification unit, 3-1 deoiling tank, 3-2 coarse desulfurization unit, 3-3 TSAII benzene removal process, 3-4 TSAII benzene removal process, 4-buffer tank, 5-preheating unit, 6-flame arrester, 7-oxygen enrichment pipeline, 8-injection device, 8-1 coke oven gas surrounding pipe, 8-2 coke oven gas branch pipe, 8-3 double-layer sleeve type coal gun, 8-4 tuyere. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the specific implementation methods of this invention will be further described below in conjunction with the embodiments. The following embodiments are used to specifically illustrate the content of this invention. These embodiments are only general descriptions of the content of this invention and do not limit the content of this invention.

[0027] like Figure 1 As shown, a blast furnace gas injection system used in a blast furnace stable injection of coke oven gas includes a coarse oil and naphthalene removal device 1, a gas compressor 2, a gas deep purification device 3, a buffer tank 4, a gas preheating device 5, a flame arrester 6, and an injection device 8 connected in sequence through a gas pipeline; the gas pipeline connecting the flame arrester 6 and the injection device 8 is connected to an oxygen-enriched pipeline 7.

[0028] The crude de-oiling de-naphthalene device 1, the coal gas compressor 2 and the coal gas deep purification device 3 are at least one working and one standby.

[0029] The coal gas deep purification device 3 comprises a de-oiling tank 3-1, a crude de-sulfur device 3-2, a TSA I de-benzene process 3-3 and a TSA II de-benzene process 3-4 connected in sequence through a coal gas pipeline.

[0030] The blowing device 8 comprises a coke oven gas surrounding pipe 8-1, a coke oven gas branch pipe 8-2, a double-layer sleeve type coal gun 8-3 and a tuyere 8-4.

[0031] The safety interlocking, detection and automatic control system device is composed of a nitrogen system, various valves, a diffusing valve, detection instruments and an automatic control system.

[0032] Embodiment: Taking a 4000m 3 Taking the blast furnace oxygen-enriched coke oven gas smelting as an example,

[0033] 1. The components and impurities of the coke oven gas are shown in Table 1 and Table 2:

[0034] Table 1: Composition of coke oven gas (volume percentage)

[0035] Component [H2] CH4 [C2H4] [C2H6] [C3H6] [C3H8] CO CO2 O2 [N2] Content % 59.605 24.135 1.809 0.601 0.094 0.032 5.785 2.005 0.602 5.332

[0036] Coke oven gas flow: 33000 Nm 3 / h (of which, after purification, ~3000 Nm 3 / h of the coke oven gas is used for TSA regeneration, and the adsorbent is regenerated by heating and blowing back the purified coke oven gas to the adsorbent);

[0037] Coke oven gas pipeline network pressure: ≥6kPa;

[0038] Temperature: ≤40℃;

[0039] Table 2: Impurity content of coke oven gas

[0040] Impurity component Tar + dust [CAT] Naphthalene Benzene HCN [H2S] Organic sulphur Composition (mg / Nm 3 )] ≤50 ≤100 ≤200 ≤2000 ≤100 ≤50 ≤200

[0041] 2. Purified product specifications:

[0042] Purified coke oven gas production: 30000 Nm 3 / h;

[0043] Pressure: ~0.7MPa;

[0044] Temperature: ≤40℃;

[0045] 3. Product purification control index:

[0046] Tar content ≤0.1 mg / Nm3 ;

[0047] Naphthalene content ≤ 0.1 mg / Nm 3 ;

[0048] Benzene content ≤ 1 mg / Nm 3 ;

[0049] 4. The detailed implementation process is as follows:

[0050] 1) The initially purified coke oven gas is introduced from a gas tank, and after being treated by the crude oil removal and naphthalene removal device 1, the naphthaline content in the coke oven gas is reduced to < 4 mg / Nm 3 , and the tar content is reduced to < 1 mg / Nm 3 .

[0051] 2) Then, the coke oven gas is pressurized to 0.8 MPa by the gas compressor 2, and after being compressed (40℃, 0.8 MPa(g)), the coke oven gas enters the oil removal tank 3-1, and the naphthaline and tar contents in the gas are reduced to 1 mg / Nm 3 or below, and then is sent to the dry crude desulfurization device 3-2 for crude desulfurization.

[0052] 3) After the coke oven gas is treated by the fine oil removal and naphthaline removal process, the gas enters the crude desulfurization device 3-2, and the H2S in the gas is removed to ≤ 1 mg / Nm 3 . The crude desulfurization uses the alkali-modified raw carbon adsorbent SQ105.

[0053] 4) After the crude desulfurization, the coke oven gas goes to the TSA I process 3-3, and the raw gas enters the TSA I benzene removal process at a temperature of ≤ 40℃, and the impurity components are removed, with the benzene content ≤ 10 mg / Nm 3 . The TSA process uses a full dry purification process, and after the adsorbent is saturated, it is regenerated by heating the purified coke oven gas, and after being cooled, is put into the next cycle for use.

[0054] 5) After the raw gas is treated by the TSA I benzene removal process 3-3, it enters the TSA II benzene removal process 3-4, and the impurity components are removed, so that the benzene content in the final purified gas is ≤ 1 mg / Nm 3 , the tar content is ≤ 0.1 mg / Nm 3 , and the naphthaline content is ≤ 0.1 mg / Nm 3 . After the adsorbent is saturated, it is regenerated by heating the purified coke oven gas, and after being cooled, is put into the next cycle for use.

[0055] 6) The purified coke oven gas is sent to the buffer tank 4 and then enters the preheating device 5. The buffer tank 4 plays a role of pressure stabilization, and the preheating device 5 preheats the purified coke oven gas to 80-100℃;

[0056] 7) After the fire arrester 6, increase the oxygen-rich pipeline 7, so that oxygen and coke oven gas enter the coke oven gas surrounding pipe together, and are sprayed into the blast furnace hearth through the coke oven gas branch pipe 8-2. The increase of the oxygen-rich pipeline 7 can increase the combustion rate of the pulverized coal and reduce the amount of unburned pulverized coal. At the same time, oxygen and coke oven gas enter the blast furnace together, so that the hydrocarbon substances such as CH4 in the coke oven gas can be fully combusted;

[0057] 8) The coke oven gas and oxygen enter the inner pipe of the double-layer sleeve type coal gun 8-3 through the gas branch pipe 8-2, and the pulverized coal sprayed through the pulverized coal distributor enters the outer pipe of the double-layer sleeve type coal gun 8-3. In this way, the pulverized coal can be contacted with oxygen in the blast before the tuyere 8-4, so as to achieve the purpose of more sufficient combustion and reduce the amount of unburned pulverized coal.

Claims

1. A process for stable injection of coke oven gas in blast furnace, characterized by, Comprise: 1) The coke oven gas first enters the deoiling tank, and the naphthalene and tar content in the gas is reduced to 1 mg / Nm 3 The following is sent to the crude desulfurization device for crude desulfurization, and H2S in the gas is removed to ≤1 mg / Nm 3 ; 2) then pressurized to 0.8Mpa by the gas compressor, the compressed coke oven gas enters the deoiling tank, the naphthalene and tar content in the gas is reduced to 1mg / Nm 3 The following is sent to the dry rough desulfurization device for rough desulfurization; 3) the coke oven gas after rough desulfurization enters the TSA I benzene removal process at a temperature of <40°C, so that the benzene in the gas is <10 mg / Nm 3 , and then enters the TSA II benzene removal process, so that the benzene in the final purified gas is <1 mg / Nm 3 , the tar is <0.1 mg / Nm 3 , and the naphthalene is <0.1 mg / Nm 3 ; 4) the purified coke oven gas is preheated to 80-100℃; 5) oxygen is introduced into the gas pipeline after the flame arrester, so that the oxygen and the purified coke oven gas enter the coke oven gas surrounding pipe together, and then enter the inner pipe of the double-layer sleeve type coal gun through the coke oven gas branch pipe, while the pulverized coal enters the outer pipe of the double-layer sleeve type coal gun through the pulverized coal distributor; the coke oven gas, oxygen and pulverized coal are simultaneously injected into the blast furnace hearth.

2. A process for stable injection of coke oven gas in blast furnace as claimed in claim 1 wherein, The crude oil and naphthalene removal device in step 1) above adopts activated carbon microspheres filling.

3. A process for stable injection of coke oven gas in blast furnace as claimed in claim 1 wherein, The oil removal tank in step 2) above adopts activated carbon fiber filling, and the crude desulfurization device adopts alkali modified raw carbon adsorbent SQ105.

4. A process for stable injection of coke oven gas in blast furnace as claimed in claim 1 wherein, The TSA I process in step 3) above adopts activated carbon microspheres as the adsorbent, and the TSA II process adopts activated carbon adsorbent SQ105.

5. A process for stable injection of coke oven gas in blast furnace as claimed in claim 1 wherein, The oxygen accounts for ≤5% of the total gas content in step 5) above.

6. A blast furnace gas injection system for use in the process of stabilizing injection of coke oven gas in a blast furnace as claimed in any one of claims 1 to 5, characterized in that, Comprise the crude oil and naphthalene removal device, the gas compressor, the gas deep purification device, the buffer tank, the preheating device, the flame arrester and the injection device connected in sequence through the gas pipeline; the oxygen enrichment pipeline is connected to the gas pipeline connected with the flame arrester and the injection device.

7. A blast furnace coal gas injection system for use in the process of stable injection of coke oven gas in a blast furnace as claimed in claim 6 wherein, The crude oil and naphthalene removal device, the gas compressor and the gas deep purification device are at least two sets of one working and one standby.

8. A blast furnace coal gas injection system for use in the process of stable injection of coke oven gas in a blast furnace as claimed in claim 6, wherein, The gas deep purification device comprises the oil removal tank, the crude desulfurization device, the TSA I benzene removal process and the TSA II benzene removal process connected in sequence through the gas pipeline.

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