Hydrogen-rich petrochemical tail gas coupled with top gas recycling method and vertical furnace loop process system

Abstract

The present invention belongs to the technical field of metallurgical industry, and specifically discloses a method for recycling hydrogen-rich petrochemical tail gas coupled with furnace top gas and a vertical furnace loop process system. The method comprises the following steps: dust removal and purification of the hot gas discharged from the upper part of the vertical furnace to obtain clean gas; separation of loop circulating gas containing H2 and CO and high-concentration CO2 mixed gas from the clean gas; mixing the loop circulating gas with hydrogen-rich petrochemical tail gas, and preheating the hydrogen-rich petrochemical tail gas to form a mixed gas; heating the mixed gas to a preset temperature range, and then passing it into a vertical furnace for reduction to produce sponge iron. The method of the present invention uses petrochemical tail gas as a supplementary raw material gas for the vertical furnace process system, integrates petrochemical tail gas containing energy media such as hydrogen and carbon with the steel smelting process, realizes the "waste to treasure" of waste gas energy, couples the top gas high-temperature removal technology, realizes the utilization of the waste heat of the loop gas, does not require a gas reforming or preparation system, and simplifies the configuration, land occupation and investment cost of the gas treatment system.

Description

Technical Field

[0001] The invention relates to the field of metallurgical industry, and in particular to a method for recycling hydrogen-rich petrochemical tail gas coupled with furnace top gas and a vertical furnace loop process system. Background Art

[0002] Compared with the traditional blast furnace ironmaking process, the main technical feature of the gas-based vertical furnace direct reduction process is to transform the energy structure, abandon high-carbon coking coal resources, and use fossil energy media with less carbon and more hydrogen as reducing agents. It is also an important direction for realizing the short-process application of steel production, effectively reducing carbon emissions, and achieving green and efficient production.

[0003] At present, the gas-based vertical furnace devices and process technology routes in operation and production in the world mainly use the method of external reforming of natural gas or self-reforming in the furnace to produce H2 and CO as effective reducing gas for vertical furnace production, which is relatively complicated in the supply and preparation process of gas source. In addition, carbon oxides such as CO2 produced by the top gas of the vertical furnace are generally washed and cooled to room temperature in advance, and then treated and separated by conventional pressure swing adsorption devices or wet decarbonization devices. The sensible heat of the top gas is wasted or can only be partially utilized, thereby achieving the quality improvement and reuse of the circulating gas.

[0004] Petrochemical tail gas is waste gas generated during the production process of petroleum and chemical industries. For the sake of production safety, petroleum refineries simply vent and ignite it directly. This not only results in the waste of hydrogen and carbon-rich gas energy, but also causes a certain degree of pollution to the environment, and fails to achieve effective utilization of waste energy. Summary of the invention

[0005] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a hydrogen-rich petrochemical tail gas coupled top gas recycling method and a vertical furnace loop process system to solve the problems in the prior art where hydrogen-rich petrochemical tail gas and top gas are not effectively utilized.

[0006] To achieve the above-mentioned purpose and other related purposes, the present invention provides a method for recycling hydrogen-rich petrochemical tail gas coupled with furnace top gas, comprising the following steps:

[0007] The hot coal gas discharged from the upper part of the vertical furnace is subjected to dust removal and purification treatment to obtain clean coal gas; a loop circulating gas containing H2 and CO and a high-concentration CO2 mixed gas are separated from the clean coal gas; the loop circulating gas is mixed with hydrogen-rich petrochemical tail gas, and the hydrogen-rich petrochemical tail gas is preheated to form a mixed coal gas; after the mixed coal gas is heated to a preset temperature range, it is passed into the vertical furnace for reduction to produce sponge iron.

[0008] Furthermore, the hot coal gas discharged from the upper part of the vertical furnace is sent to the coal gas dust removal equipment for dust removal and purification.

[0009] Furthermore, the coal gas dust removal equipment is selected from a hot cyclone dust removal device and / or a high-temperature dry bag device; preferably, the coal gas dust removal equipment includes a hot cyclone dust removal device and a high-temperature dry bag device arranged in sequence.

[0010] Furthermore, the clean gas temperature after dust removal and purification is 300℃~550℃, and the dust content of the clean gas is less than 8mg / Nm 3 .

[0011] Furthermore, the clean coal gas is sent to the high-temperature coal gas decarbonization equipment to separate the loop circulating gas containing H2 and CO and the high-concentration CO2 mixed gas.

[0012] Furthermore, the high-temperature coal gas decarbonization equipment is a carbon dioxide removal device. When in use, the carbon dioxide removal device is in a high-temperature operating condition, so there is no need to pre-cool the clean coal gas at the inlet of the high-temperature coal gas decarbonization equipment.

[0013] Furthermore, the temperature of the inlet gas of the high-temperature coal gas decarbonization equipment is ≤600°C.

[0014] Furthermore, the loop circulating gas containing H2 and CO and the high-concentration CO2 mixed gas separated by the carbon dioxide removal device in high-temperature operation conditions have a gas temperature of 300°C to 600°C.

[0015] Furthermore, the volume percentage of non-carbon dioxide gas in the high-concentration CO2 mixed gas is less than 10%.

[0016] Furthermore, the high-concentration CO2 mixed gas is used as a supplementary fuel gas to heat the mixed coal gas.

[0017] Furthermore, 80% or more of the loop circulating gas is mixed with hydrogen-rich petrochemical tail gas to form a mixed coal gas, and the remaining loop circulating gas is used as fuel gas to heat the mixed coal gas; preferably, 85% to 90% of the loop circulating gas is mixed with hydrogen-rich petrochemical tail gas to form a mixed coal gas, and the remaining loop circulating gas is used as fuel gas to heat the mixed coal gas.

[0018] Furthermore, the temperature of the mixed gas formed by mixing the loop circulating gas with the hydrogen-rich petrochemical tail gas is 300-600°C.

[0019] Furthermore, the temperature of the hydrogen-rich petrochemical tail gas is 20-40° C., and includes the following chemical components in volume percentage: H2 75-95%, CH4<6.0%, C2+alkanes<5.0%, CO2<3.0%, and N2<4.0%.

[0020] Furthermore, during blending, the supplementary amount of the hydrogen-rich petrochemical tail gas is 30 to 60% of the volume flow of the loop circulating gas containing H2 and CO.

[0021] Furthermore, the mixed coal gas is heated by a heating furnace, and the heating furnace is preferably a tubular heating furnace.

[0022] Furthermore, the mixed coal gas is heated to 820-1050° C. and then introduced into a vertical furnace for reduction to produce sponge iron.

[0023] The present invention also provides a vertical furnace loop process system, comprising a coal gas dust removal device, a high-temperature coal gas decarbonization device, a gas mixer, and a heating furnace which are sequentially connected through an air pipe, wherein the air inlet end of the coal gas dust removal device is connected to the upper part of the vertical furnace through an air pipe, the high-temperature coal gas decarbonization device is provided with a loop circulating gas outlet and a high-concentration CO2 mixed gas outlet, the loop circulating gas outlet is respectively connected to the gas mixer and the heating furnace through an air pipe, the high-temperature coal gas decarbonization device is also connected to the heating furnace through an air pipe, the gas mixer is provided with a hydrogen-rich petrochemical tail gas inlet, and the gas outlet end of the heating furnace is connected to the middle part of the vertical furnace through an air pipe.

[0024] Furthermore, the coal gas dust removal equipment is selected from a hot cyclone dust removal device and / or a high-temperature dry bag device; preferably, the coal gas dust removal equipment includes a hot cyclone dust removal device and a high-temperature dry bag device arranged in sequence.

[0025] Furthermore, the high-temperature coal gas decarbonization equipment is a carbon dioxide removal device.

[0026] Furthermore, the heating furnace is a tubular heating furnace.

[0027] As described above, the hydrogen-rich petrochemical tail gas coupled top gas recycling method and the vertical furnace loop process system of the present invention have the following beneficial effects:

[0028] 1. The method provided by the present invention uses the smelting tail gas produced in the petrochemical field as the supplementary raw material gas of the vertical furnace process system, integrates and applies the hydrogen-rich petrochemical tail gas containing energy media such as hydrogen and carbon with the steel smelting process, and realizes the "waste to treasure" of waste gas resources, which not only reduces the environmental pollution caused by simple combustion and emission treatment, but also enriches the ways to effectively utilize waste energy.

[0029] 2. The method provided by the present invention uses hydrogen-rich petrochemical tail gas as a supplementary gas source and couples it with the high-temperature removal technology of the top gas without cooling to achieve effective utilization of the waste heat of the top gas in the whole process system of the vertical furnace. At the same time, the tail gas conventionally treated by simple combustion in the chemical industry is "turned into treasure", and the effective combination of chemical waste gas and metallurgical process is achieved, which simplifies the process gas preparation system, shortens the process layout, land occupation and investment costs, and the process operation energy consumption and carbon emissions have more comparative advantages.

[0030] 3. The vertical furnace loop process system provided by the present invention, in conjunction with the hydrogen-rich petrochemical tail gas coupled with the vertical furnace top gas high-temperature removal technology without cooling, realizes the effective utilization of the waste heat of the vertical furnace loop gas, without the need to supplement the raw gas reforming or preparation system, and simplifies the configuration, land occupation and investment cost of the gas treatment system. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Shown is a schematic diagram of the process of coupling the hydrogen-rich petrochemical tail gas with the top gas recycling method in an embodiment of the present invention, as well as a schematic diagram of the layout of the vertical furnace loop process system.

[0032] Description of reference numerals:

[0033] Vertical furnace 1, hot cyclone dust removal device 2, high-temperature dry bag device 3, high-temperature coal gas decarbonization equipment 4, gas mixer 5, heating furnace 6, hot coal gas P0, clean coal gas P1, loop circulating gas P2, high-concentration CO2 mixed gas P3, hydrogen-rich petrochemical tail gas P4, sponge iron F. DETAILED DESCRIPTION

[0034] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0035] It should be noted that the diagram provided in the present embodiment only illustrates the basic concept of the present invention in a schematic manner, so the diagram only shows the components related to the present invention rather than drawing according to the number, shape and size of the components during actual implementation. The type, quantity and ratio of each component during actual implementation can be a random change, and the component layout type may also be more complicated. The structure, ratio, size, etc. illustrated in the drawings of the present specification are only used to match the content disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions that the present invention can implement, so they have no technical substantive significance. Any modification of the structure, change of the proportional relationship or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the effect that the present invention can produce and the purpose that can be achieved. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of narration, and are not used to limit the scope of the present invention. The change or adjustment of its relative relationship should also be regarded as the scope of the present invention without substantially changing the technical content.

[0036] Combination Figure 1As shown, an embodiment of the present application provides a method for recycling hydrogen-rich petrochemical tail gas coupled with furnace top gas, comprising the following steps:

[0037] The hot coal gas P0 discharged from the upper part of the vertical furnace 1 is subjected to dust removal and purification treatment to obtain clean coal gas P1; a loop circulating gas P2 containing H2 and CO and a high-concentration CO2 mixed gas are separated from the clean coal gas P1; the loop circulating gas P2 is mixed with hydrogen-rich petrochemical tail gas P4, and the hydrogen-rich petrochemical tail gas P4 is preheated to form a mixed coal gas; after the mixed coal gas is heated to a preset temperature range, it is introduced into the vertical furnace 1 for reduction to produce sponge iron F.

[0038] In some embodiments, the hot coal gas P0 discharged from the upper part of the vertical furnace 1 is sent to the coal gas dust removal equipment for dust removal and purification. The coal gas dust removal equipment is selected from the hot cyclone dust removal device 2 and / or the high-temperature dry bag device 3; preferably, the coal gas dust removal equipment includes the hot cyclone dust removal device 2 and the high-temperature dry bag device 3 arranged in sequence.

[0039] In some embodiments, the temperature of the clean coal gas P1 after dust removal and purification is 300°C to 550°C, and the dust content of the clean coal gas P1 is less than 8 mg / Nm 3 .

[0040] In some embodiments, the clean coal gas P1 is sent to the high-temperature coal gas decarbonization equipment 4 to separate the loop circulating gas P2 containing H2 and CO and the high-concentration CO2 mixed gas. The high-temperature coal gas decarbonization equipment 4 is a carbon dioxide removal device. When in use, the carbon dioxide removal device is in a high-temperature operating condition, so there is no need to pre-cool the clean coal gas P1 at the inlet of the high-temperature coal gas decarbonization equipment 4.

[0041] Furthermore, in some embodiments, the temperature of the inlet coal gas of the high-temperature coal gas decarbonization device 4 is ≤600°C; the loop circulating gas P2 containing H2 and CO separated by the carbon dioxide removal device in high-temperature operation and the high-concentration CO2 mixed gas, the coal gas temperature of the two gas streams is 300°C to 600°C. Wherein, the volume percentage of non-carbon dioxide gas in the high-concentration CO2 mixed gas is less than 10%.

[0042] In some embodiments, the high-concentration CO2 mixed gas can be used as a supplementary fuel gas to heat the mixed coal gas.

[0043] The carbon dioxide removal device in the embodiment of the present application can be a device for removing carbon dioxide by adsorbing carbon dioxide in the mixed gas through a CO2 adsorbent. Among them, the CO2 adsorbent is preferably a fine-grained high-temperature solid adsorbent, which can adsorb CO2 at a relatively high temperature (600°C), and can be specifically selected from at least one of magnesium oxide, calcium oxide, magnesium-calcium complex, lithium / zirconium silicate and its complex / modified material, such as magnesium oxide, calcium oxide, magnesium oxide-calcium oxide complex, lithium zirconate Li2ZrO3, lithium silicate Li4SiO4, lithium zirconate-lithium silicate complex, etc., but not limited thereto; the particle size distribution range is generally controlled at 0.15mm~1.0mm. For the specific structural setting and other technical parameters of the carbon dioxide removal device, the embodiment of the present application does not make any special restrictions, and common or existing equipment in the field can be used.

[0044] In some embodiments, 80% or more of the loop circulating gas P2 is mixed with the hydrogen-rich petrochemical tail gas P4 to form a mixed coal gas, and the remaining loop circulating gas P2 is used as fuel gas to heat the mixed coal gas; preferably, 85% to 90% of the loop circulating gas P2 is mixed with the hydrogen-rich petrochemical tail gas P4 to form a mixed coal gas, and the remaining loop circulating gas P2 is used as fuel gas to heat the mixed coal gas.

[0045] Furthermore, in some embodiments, the temperature of the mixed gas formed by mixing the loop circulating gas P2 with the hydrogen-rich petrochemical tail gas P4 is 300-600°C.

[0046] In some embodiments, the hydrogen-rich petrochemical tail gas P4 has a temperature of 20-40° C. and includes the following chemical components in volume percentage: H2 75-95%, CH4<6.0%, C2+alkanes<5.0%, CO2<3.0%, and N2<4.0%.

[0047] In some embodiments, during blending, the supplementary amount of the hydrogen-rich petrochemical tail gas P4 is 30-60% of the volume flow of the loop circulating gas P2 containing H2 and CO.

[0048] In some embodiments, the mixed coal gas is heated by a heating furnace 6, and the heating furnace 6 is preferably a tubular heating furnace.

[0049] In some embodiments, the mixed coal gas is heated to 820-1050° C. and then introduced into the vertical furnace 1 for reduction to produce sponge iron F.

[0050] The method provided in the above embodiment uses the smelting tail gas generated in the petrochemical field as the supplementary raw material gas for the vertical furnace process system, and integrates and applies the hydrogen-rich petrochemical tail gas containing energy media such as hydrogen and carbon with the steel smelting process, thereby realizing the "waste to treasure" of waste gas resources, which not only reduces the environmental pollution caused by simple combustion and emission treatment, but also enriches the ways to effectively utilize waste energy.

[0051] At the same time, the method provided in the above embodiment adopts hydrogen-rich petrochemical tail gas as a supplementary gas source and couples the top gas high-temperature removal technology without cooling to achieve effective utilization of the top gas waste heat in the whole process system of the vertical furnace. At the same time, the tail gas conventionally treated by simple combustion in the chemical industry is "turned into treasure", and the effective combination of chemical waste gas and metallurgical process is achieved, which simplifies the process gas preparation system, shortens the process layout, land occupation and investment costs, and the process operation energy consumption and carbon emissions have more comparative advantages.

[0052] Combination Figure 1 As shown, an embodiment of the present application also provides a vertical furnace loop process system, including a coal gas dust removal device, a high-temperature coal gas decarbonization device 4, a gas mixer 5, and a heating furnace 6 which are sequentially connected through an air pipe, wherein the air inlet end of the coal gas dust removal device is connected to the upper part of the vertical furnace 1 through an air pipe, the high-temperature coal gas decarbonization device 4 is provided with a loop circulating gas P2 outlet and a high-concentration CO2 mixed gas outlet, the loop circulating gas P2 outlet is respectively connected to the gas mixer 5 and the heating furnace 6 through an air pipe, the high-temperature coal gas decarbonization device 4 is also connected to the heating furnace 6 through an air pipe, the gas mixer 5 is provided with a hydrogen-rich petrochemical tail gas P4 inlet, and the gas outlet end of the heating furnace 6 is connected to the middle part of the vertical furnace 1 through an air pipe.

[0053] In some embodiments, the coal gas dust removal equipment is selected from a hot cyclone dust removal device 2 and / or a high-temperature dry bag device 3; preferably, the coal gas dust removal equipment includes a hot cyclone dust removal device 2 and a high-temperature dry bag device 3 arranged in sequence.

[0054] In some embodiments, the high temperature coal gas decarbonization equipment 4 is a carbon dioxide removal device.

[0055] In some embodiments, the heating furnace 6 is a tubular heating furnace.

[0056] The vertical furnace loop process system provided in the above embodiment, in conjunction with the high-temperature removal technology of hydrogen-rich petrochemical tail gas coupled with vertical furnace top gas without cooling, realizes the effective utilization of the waste heat of the vertical furnace loop gas, without the need to supplement the raw gas reforming or preparation system, and simplifies the configuration, land occupation and investment cost of the gas treatment system.

[0057] Combination Figure 1 As shown, another embodiment of the present application provides a method for recycling hydrogen-rich petrochemical tail gas coupled with furnace top gas, comprising the following steps:

[0058] 1) The hot coal gas P0 discharged from the upper part of the direct reduction vertical furnace 1 first enters the hot cyclone dust removal device 2, and then enters the dry bag system for secondary dust removal. The clean coal gas P1 after dust removal enters the high-temperature high-temperature coal gas decarbonization equipment 4 to separate the loop circulating gas P2 containing H2 and CO and the high-concentration CO2 mixed gas. The loop circulating gas P2 containing H2 and CO output from the high-temperature high-temperature coal gas decarbonization equipment 4 is mixed with the pretreated hydrogen-rich petrochemical tail gas P4 to form a mixed coal gas with a preheating temperature of about 300°C, and then further introduced into the heating furnace 6, heated to about 860°C, and then introduced into the vertical furnace 1 for reduction to produce sponge iron F.

[0059] 2) In the above step 1), after hot cyclone dust removal, the dry bag system is loaded with clean coal gas P1 after secondary dust removal, the temperature of which is 325°C, and the dust content of clean coal gas P1 is 5mg / Nm 3 .

[0060] 3) The high-temperature coal gas decarbonization equipment 4 in the above step 1) is a device suitable for removing CO2 under high temperature conditions. The inlet gas temperature of the decarbonization equipment is 325°C. The CO2 adsorption material in the high-temperature coal gas decarbonization equipment 4 is a magnesium and calcium complex. The adsorption material is in the form of solid fine particles with a particle size distribution of 0.5mm~1.0mm accounting for 60%.

[0061] 4) In the above step 1), the temperature of the loop circulating gas P2 containing H2 and CO and the high-concentration CO2 mixed gas separated by the high-temperature high-temperature coal gas decarbonization equipment 4 is about 320°C;

[0062] 5) In the above step 1), the high-concentration CO2 mixed gas discharged from the high-temperature coal gas decarbonization equipment 4 has a non-CO2 content of 9.2% (volume percentage) in the gas flow and is used as a supplementary fuel gas for the heating system.

[0063] 6) In the above step 1), 88% (volume percentage) of the loop circulating gas P2 containing H2 and CO discharged from the high-temperature coal gas decarbonization equipment 4 is mixed with the supplementary hydrogen-rich petrochemical tail gas P4, and the petrochemical tail gas is preheated to form a mixed coal gas with a preheating temperature of about 300°C. Another part of 12% (volume percentage) of the circulating gas loop circulating gas P2 is extracted from the pipeline and used as fuel gas for the heating system.

[0064] 7) In the above step 6), the supplemented hydrogen-rich petrochemical tail gas P4 has a temperature range of 40°C and its main chemical components are: H2 content 87.4%, CO content 2.5%, CH4 content 4.96%, C n H m (n≥2) content 1.58%, CO2 content 1.0%, N2 content 3.60%.

[0065] 8) In the above step 6), the flow rate of the supplementary hydrogen-rich petrochemical tail gas P4 is 52% of the flow rate of the loop circulating gas P2 containing H2 and CO.

[0066] Combination Figure 1 As shown, another embodiment of the present application provides a method for recycling hydrogen-rich petrochemical tail gas coupled with furnace top gas, comprising the following steps:

[0067] 1) The hot coal gas P0 discharged from the upper part of the direct reduction vertical furnace 1 first enters the hot cyclone dust removal device 2, and then enters the dry bag system for secondary dust removal. The clean coal gas P1 after dust removal enters the high-temperature high-temperature coal gas decarbonization equipment 4 to separate the loop circulating gas P2 containing H2 and CO and the high-concentration CO2 mixed gas. The loop circulating gas P2 containing H2 and CO output from the high-temperature high-temperature coal gas decarbonization equipment 4 is mixed with the pretreated hydrogen-rich petrochemical tail gas P4 to form a preheating temperature of about 342°C mixed coal gas, which is further introduced into the heating furnace 6. After being heated to about 910°C, it is introduced into the vertical furnace 1 for reduction to produce sponge iron F.

[0068] 2) In the above step 1), after hot cyclone dust removal, the dry bag system is loaded with clean coal gas P1 after secondary dust removal, the temperature of which is 360°C, and the dust content of clean coal gas P1 is 3mg / Nm 3 .

[0069] 3) The high-temperature coal gas decarbonization equipment 4 in the above step 1) is a device suitable for removing CO2 under high temperature conditions. The inlet coal gas temperature of the decarbonization equipment is 360°C. The CO2 adsorption material in the high-temperature coal gas decarbonization equipment 4 is a lithium-zirconium silicate complex. The adsorption material is solid fine particles with a particle size distribution of 0.5mm~1.0mm accounting for 70%.

[0070] 4) In the above step 1), the temperature of the loop circulating gas P2 containing H2 and CO and the high-concentration CO2 mixed gas separated by the high-temperature coal gas decarbonization equipment 4 reaches about 349°C.

[0071] 5) In the above step 1), the high-concentration CO2 mixed gas discharged from the high-temperature coal gas decarbonization equipment 4 has a non-CO2 content of 7.8% (volume percentage) in the gas flow and is used as a supplementary fuel gas for the heating system.

[0072] 6) In the above step 1), 90% (volume percentage) of the loop circulating gas P2 containing H2 and CO discharged from the high-temperature coal gas decarbonization equipment 4 is mixed with the supplementary hydrogen-rich petrochemical tail gas P4, and the petrochemical tail gas is preheated to form a mixed coal gas with a preheating temperature of about 342°C. Another part of 10% (volume percentage) of the circulating gas loop circulating gas P2 is extracted from the pipeline and used as fuel gas for the heating system.

[0073] 7) In the above step 6), the supplemented hydrogen-rich petrochemical tail gas P4 has a temperature range of 38°C and its main chemical components are: H2 content 88.34%, CH4 content 6.62%, C n H m (n≥2) content 0.68%, CO2 content 1.14%, N2 content 2.05%.

[0074] 8) In the above step 6), the flow rate of the supplementary hydrogen-rich petrochemical tail gas P4 is 55% of the flow rate of the loop circulating gas P2 containing H2 and CO.

[0075] Combination Figure 1 As shown, another embodiment of the present application provides a method for recycling hydrogen-rich petrochemical tail gas-coupled furnace top gas, comprising the following steps:

[0076] 1) The hot coal gas P0 discharged from the upper part of the direct reduction vertical furnace 1 first enters the hot cyclone dust removal device 2, and then enters the dry bag system for secondary dust removal. The clean coal gas P1 after dust removal enters the high-temperature high-temperature coal gas decarbonization equipment 4 to separate the loop circulating gas P2 containing H2 and CO and the high-concentration CO2 mixed gas. The loop circulating gas P2 containing H2 and CO output from the high-temperature high-temperature coal gas decarbonization equipment 4 is mixed with the pretreated hydrogen-rich petrochemical tail gas P4 to form a preheating temperature of about 395°C mixed coal gas, which is further introduced into the heating furnace 6, heated to about 950°C, and then introduced into the vertical furnace 1 for reduction to produce sponge iron F.

[0077] 2) In the above step 1), after hot cyclone dust removal, the dry bag system is loaded with clean coal gas P1 after secondary dust removal, the temperature of which is 450°C, and the dust content of clean coal gas P1 is 5mg / Nm 3 .

[0078] 3) The high-temperature coal gas decarbonization equipment 4 in the above step 1) is a device suitable for removing CO2 under high temperature conditions. The inlet gas temperature of the decarbonization equipment is 450°C. The CO2 adsorption material in the high-temperature coal gas decarbonization equipment 4 is a lithium-zirconium silicate complex. The adsorption material is solid fine particles with a particle size distribution of 0.5mm to 1.0mm, accounting for 74%.

[0079] 4) In the above step 1), the temperature of the loop circulating gas P2 containing H2 and CO and the high-concentration CO2 mixed gas separated by the high-temperature coal gas decarbonization equipment 4 reaches about 435°C.

[0080] 5) In the above step 1), the high-concentration CO2 mixed gas discharged from the high-temperature coal gas decarbonization equipment 4 has a non-CO2 content of 8.0% (volume percentage) in the gas flow and is used as a supplementary fuel gas for the heating system.

[0081] 6) In the above step 1), 85% (volume percentage) of the loop circulating gas P2 containing H2 and CO discharged from the high-temperature coal gas decarbonization equipment 4 is mixed with the supplementary hydrogen-rich petrochemical tail gas P4, and the petrochemical tail gas is preheated to form a mixed coal gas with a preheating temperature of about 395°C. Another part of 15% (volume percentage) of the circulating gas loop circulating gas P2 is extracted from the pipeline and used as fuel gas for the heating system.

[0082] 7) In the above step 6), the supplemented hydrogen-rich petrochemical tail gas P4 has a temperature range of 35°C and its main chemical components are: H2 content 90.6%, CO content 2.6%, CH4 content 3.87%, C n H m Content: 1.15%, CO2 content: 0.11%, N2 content: 1.67%.

[0083] 8) In the above step 6), the flow rate of the supplementary hydrogen-rich petrochemical tail gas P4 is 43% of the flow rate of the loop circulating gas P2 containing H2 and CO.

[0084] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A method for recycling hydrogen-rich petrochemical tail gas coupled with furnace top gas, characterized in that: The method comprises the following steps: performing dust removal and purification treatment on the hot coal gas discharged from the upper part of the vertical furnace to obtain clean coal gas; separating the loop circulating gas containing H2 and CO and the high-concentration CO2 mixed gas from the clean coal gas; mixing the loop circulating gas with the hydrogen-rich petrochemical tail gas, and preheating the hydrogen-rich petrochemical tail gas to form a mixed coal gas; heating the mixed coal gas to a preset temperature range, and then introducing the mixed coal gas into the vertical furnace for reduction to produce sponge iron; The hydrogen-rich petrochemical tail gas includes the following chemical components in volume percentage: H2 75-95%, CH4<6.0%, C2+alkane<5.0%, CO2<3.0%, N2<4.0%.

2. The method for recycling hydrogen-rich petrochemical tail gas coupled with furnace top gas according to claim 1, characterized in that: The hot coal gas discharged from the upper part of the vertical furnace is sent to the coal gas dust removal equipment for dust removal and purification; And / or, the clean gas temperature after dust removal and purification is 300℃~550℃, and the dust content of the clean gas is less than 8mg / Nm 3 .

3. The method for recycling hydrogen-rich petrochemical tail gas coupled with furnace top gas according to claim 2, characterized in that: The coal gas dust removal equipment is selected from a hot cyclone dust removal device and / or a high-temperature dry bag device.

4. The method for recycling hydrogen-rich petrochemical tail gas coupled with furnace top gas according to claim 1, characterized in that: The clean coal gas is sent to the high-temperature coal gas decarbonization equipment to separate the loop circulating gas containing H2 and CO and the high-concentration CO2 mixed gas.

5. The method for recycling hydrogen-rich petrochemical tail gas coupled with furnace top gas according to claim 4, characterized in that: The high-temperature coal gas decarbonization equipment is a carbon dioxide removal device. When in use, the carbon dioxide removal device is in a high-temperature operating condition; And / or, the temperature of the coal gas at the inlet of the high-temperature coal gas decarbonization equipment is ≤ 600°C; And / or, the loop circulating gas containing H2 and CO and the high-concentration CO2 mixed gas separated by the carbon dioxide removal device in high-temperature operation conditions, the gas temperature of the two gas streams is 300°C to 600°C.

6. The method for recycling hydrogen-rich petrochemical tail gas coupled with furnace top gas according to claim 1, characterized in that: The volume percentage of non-carbon dioxide gas in the high-concentration CO2 mixed gas is less than 10%; And / or, the high concentration CO2 mixed gas is used as a supplementary fuel gas to heat the mixed coal gas.

7. The method for recycling hydrogen-rich petrochemical tail gas coupled with furnace top gas according to claim 1, characterized in that: 80% or more of the loop circulating gas is mixed with the hydrogen-rich petrochemical tail gas to form a mixed coal gas, and the remaining loop circulating gas is used as fuel gas to heat the mixed coal gas; and / or, the temperature of the mixed gas formed by mixing the loop circulating gas with the hydrogen-rich petrochemical tail gas is 300-600° C.; and / or, the temperature of the hydrogen-rich petrochemical tail gas is 20 to 40° C.; And / or, during blending, the supplementary amount of the hydrogen-rich petrochemical tail gas is 30-60% of the volume flow of the loop circulating gas containing H2 and CO.

8. The method for recycling hydrogen-rich petrochemical tail gas coupled with furnace top gas according to claim 1, characterized in that: heating the mixed coal gas by a heating furnace; And / or, the mixed coal gas is heated to 820-1050° C. and then introduced into a vertical furnace for reduction to produce sponge iron.

9. A vertical furnace loop flow system, characterized in that: It includes a coal gas dust removal device, a high-temperature coal gas decarbonization device, a gas mixer, and a heating furnace which are sequentially connected through an air pipe. The air inlet end of the coal gas dust removal device is connected to the upper part of the vertical furnace through an air pipe. The high-temperature coal gas decarbonization device is provided with a loop circulation gas outlet and a high-concentration CO2 mixed gas outlet. The loop circulation gas outlet is respectively connected to the gas mixer and the heating furnace through an air pipe. The high-temperature coal gas decarbonization device is also connected to the heating furnace through an air pipe. The gas mixer is provided with a hydrogen-rich petrochemical tail gas inlet. The gas outlet end of the heating furnace is connected to the middle part of the vertical furnace through an air pipe.

10. The vertical furnace circuit flow system according to claim 9, characterized in that: The coal gas dust removal equipment is selected from a hot cyclone dust removal device and / or a high temperature dry bag device; And / or, the high-temperature coal gas decarbonization equipment is a carbon dioxide removal device; And / or, the heating furnace is a tubular heating furnace.

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