Method for treating electric furnace off-gas and device for treating electric furnace off-gas

Abstract

The present application relates to the chemical technology field, disclose a method for processing electric furnace tail gas and processing electric furnace tail gas device, the method comprises the following steps: S1, after pretreatment electric furnace tail gas is carried out first desulfurization, obtains desulfurization raw gas;S2, the desulfurization raw gas is carried out first deoxidation, obtains deoxidation raw gas;S3, the deoxidation raw gas is mixed with water vapor and is purified, obtains shift raw gas;Wherein, the purification treatment includes second desulfurization, dechlorination, arsenic removal and second deoxidation;S4, the shift raw gas is carried out isothermal shift reaction, the gas phase product obtained is condensed and gas-liquid separation;S5, the crude shift product gas obtained by gas-liquid separation is carried out decarburization, obtains decarburization shift product gas after.The processing method of the present application is suitable for the electric furnace tail gas with higher CO content and complex gas composition.

Description

TECHNICAL FIELD

[0001] The present application relates to the chemical industry field, in particular to a method for treating tail gas of an electric furnace and a device for treating tail gas of an electric furnace. BACKGROUND

[0002] Carbon monoxide shift is an important part of modern coal chemical projects. Through the shift reaction, CO in the raw material gas is converted into H2 by reacting with steam, and the hydrogen-carbon ratio in the raw material gas is adjusted to meet the requirements of downstream devices.

[0003] The shift reaction is a reversible exothermic reaction. Traditional shift technology generally uses multiple adiabatic shift reactors in series to achieve the required shift depth. With the continuous development of coal gasification technology, dry pulverized coal quenching process gasification technology has been widely applied. The crude coal gas produced by this type of gasification technology has the characteristics of high water content and high CO content. If it is directly introduced into the shift furnace for reaction, the temperature of the catalyst bed will be as high as 500℃ or above, which will seriously affect the service life of the catalyst and the safe operation of the system. Traditional adiabatic shift technology generally uses high water-gas ratio or low water-gas ratio process to prevent the catalyst bed from overheating. However, neither the high water-gas ratio process nor the low water-gas ratio process can fundamentally solve the problem of using catalysts at high temperatures. In recent years, isothermal shift technology has been paid attention by many scientific research units and enterprises, and has made breakthrough development.

[0004] US6033634 discloses a hydrogen manufacturing device having a plate-type high-temperature shift furnace with a shift reaction chamber filled with high-temperature shift catalyst, a cooling chamber with a packing to promote heat transfer, cooling gas introduced into the cooling chamber, and a partition separating the shift reaction chamber and the cooling chamber. The shift reaction chamber has a light chamber and a hydrogen-permeable palladium module separated by a plate-type partition. Therefore, only hydrogen generated in the shift reaction chamber can enter the hydrogen chamber through the hydrogen-permeable module.

[0005] CN1461730A discloses a carbon monoxide shift process and a reactor. The process steps include: introducing raw material gas into the reactor tube of the reaction unit, the reactor tube having a fixed bed of shift catalyst in the reaction zone; contacting the raw material gas with the catalyst under shift reaction conditions effective to react carbon monoxide with steam to produce hydrogen; cooling medium has a descending module form flowing along the outer shell of the reactor tube, the reaction is cooled by non-direct heat exchange with the cooling medium, and heated cooling medium is removed from the descending module, hydrogen produced by the shift reaction passes through a hydrogen-selective module to reach a permeation zone; hydrogen is extracted from the permeation zone and carbon monoxide-depleted raw material gas is discharged from the reaction zone.

[0006] A large amount of tail gas is generated in the production process of ferroalloy reduction electric furnace, and the effective fuel components such as CO, H2 and CH4 in the tail gas account for about 80% of the gas volume, mainly CO, and the calorific value is 2100-2400 kcal / m. The electric furnace tail gas is difficult to treat due to its complex composition, and it has been a technical problem. The traditional treatment method cannot meet the environmental protection requirements. Under the new environmental protection requirements, how to reduce the emission of waste gas, realize the utilization efficiency of electric furnace tail gas, improve the ecological environment, realize the industrial upgrading, energy saving and consumption reduction is a new topic. SUMMARY

[0007] The purpose of the present application is to overcome the problems of low utilization efficiency of electric furnace tail gas and more waste gas emission in the prior art, and provide a treatment method of electric furnace tail gas and a device for treating electric furnace tail gas. The treatment method can effectively reduce the emission of waste gas and realize the efficient utilization of electric furnace tail gas, so that the CO in the electric furnace tail gas has a high conversion rate.

[0008] In order to achieve the above purpose, the first aspect of the present application provides a treatment method of electric furnace tail gas, which comprises the following steps:

[0009] S1, the pre-treated electric furnace tail gas is subjected to first desulfurization to obtain desulfurized raw gas;

[0010] S2, the desulfurized raw gas is subjected to first deoxidation to obtain deoxidized raw gas;

[0011] S3, the deoxidized raw gas is mixed with water vapor for purification treatment to obtain shift raw gas; wherein, the purification treatment comprises second desulfurization, dechlorination, dearsenication and second deoxidation;

[0012] S4, the shift raw gas is subjected to isothermal shift reaction, and the gas phase product obtained is subjected to condensation and gas-liquid separation;

[0013] S5, the crude shift product gas obtained by the gas-liquid separation is subjected to decarburization to obtain decarburized shift product gas.

[0014] The second aspect of the present application provides a device for treating electric furnace tail gas, wherein the device comprises: a pretreatment furnace, a desulfurization unit, a deoxidation furnace, a purification furnace, an isothermal shift reaction furnace, a gas-liquid separation unit and a temperature swing adsorption column which are sequentially communicated; wherein,

[0015] The pretreatment furnace is used for pretreating the electric furnace tail gas to remove oil stains and dust, so as to obtain pre-treated electric furnace tail gas;

[0016] The desulfurization unit is used for first desulfurizing the pre-treated electric furnace tail gas to obtain desulfurized raw gas;

[0017] The deoxidizing furnace is used for first deoxidizing the desulfurized raw gas, so as to obtain a deoxidized raw gas;

[0018] The purification furnace is filled with a desulfurizing agent, a dechlorinating agent, a dearsenizing agent and a deoxidizing agent, which are respectively used for second desulfurizing, dechlorinating, dearsenizing and second deoxidizing the deoxidized raw gas, so as to obtain a shift raw gas;

[0019] The isothermal shift reaction furnace is used for isothermal shift reaction of the shift raw gas, so as to convert CO in the shift raw gas into H2 and CO2;

[0020] The gas-liquid separation unit comprises a water cooling system and a gas-liquid separator, which are used for condensing and gas-liquid separating the gaseous phase product obtained by the isothermal shift reaction, so as to obtain a crude shift product gas flowing out from the upper part of the gas-liquid separator;

[0021] The temperature swing adsorption tower is used for removing CO2 in the crude shift product gas.

[0022] Through the above technical solution, the present application has the following beneficial effects:

[0023] The isothermal shift reaction furnace of the present application can effectively and quickly remove the heat generated by the reaction, and has a good protective effect on the isothermal shift catalyst used, so that the use conditions of the catalyst are widened.

[0024] The present application can effectively remove sulfides, oxygen, chlorides and arsenic in the electric furnace tail gas by sequentially performing first desulfurization and first deoxidization on the pretreated electric furnace tail gas, and then sequentially performing second desulfurization, dechlorination, dearsenization and second deoxidization. The purification effect is remarkable, and the shift raw gas obtained by removing sulfides, oxygen, chlorides and arsenic has low content. When the shift raw gas is subjected to isothermal shift reaction, it can meet the use requirements of the isothermal shift reaction catalyst, thereby increasing the source range of the electric furnace tail gas. The processing method of the present application can be used for a wide range of electric furnace tail gas raw gas, and is suitable for electric furnace tail gas with high CO content and complex gas composition. The processing method provided by the present application can reduce the emission of carbon dioxide gas and realize efficient utilization of electric furnace tail gas, so that the CO in the electric furnace tail gas has a high conversion rate. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a process flow diagram for processing electric furnace tail gas in a specific embodiment of the present application. DETAILED DESCRIPTION

[0026] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0027] The first aspect of this invention provides a method for treating electric furnace exhaust gas, the method comprising the following steps:

[0028] S1. The pretreated electric furnace tail gas is subjected to the first desulfurization to obtain desulfurization raw material gas;

[0029] S2. Perform a first deoxygenation on the desulfurization feed gas to obtain deoxygenated feed gas;

[0030] S3. The deoxygenated feed gas is mixed with water vapor for purification treatment to obtain shift feed gas; wherein, the purification treatment includes second desulfurization, dechlorination, dearsenic removal and second deoxygenation;

[0031] S4. The shifted raw material gas is subjected to an isothermal shift reaction, and the resulting gaseous product is condensed and separated into gas and liquid phases.

[0032] S5. Decarbonize the crude shift product gas obtained from the gas-liquid separation to obtain decarbonized shift product gas.

[0033] In this invention, the electric furnace exhaust gas mainly contains components such as CO, H2, CO2, N2, O2, and CH4, as well as chlorides, sulfides, and arsenides. According to this invention, preferably, the CO content in the electric furnace exhaust gas is 60-75 vol%, the hydrogen content is 3-6 vol%, the carbon dioxide content is 11-16 vol%, the nitrogen content is 12-16 vol%, the methane content is 0.01-0.03 vol%, the oxygen content is 0.02-0.08 vol%, the sulfide content is less than or equal to 0.15 ppm, the chloride content is less than or equal to 0.15 ppm, and the arsenide content is less than or equal to 0.01 ppm. For electric furnace exhaust gas with such high CO content and complex gas composition, the treatment method provided by this invention can reduce carbon dioxide emissions and achieve efficient utilization of the electric furnace exhaust gas, resulting in a high CO conversion rate.

[0034] The present application sequentially carries out first desulfurization and first deoxidation on the pretreated electric furnace tail gas, and then sequentially carries out second desulfurization, dechlorination, arsenic removal and second deoxidation. Through these treatments, sulfides, oxygen, chlorides and arsenic in the electric furnace tail gas can be effectively removed, the purification effect is remarkable, and the obtained shift raw gas with low content of sulfides, oxygen, chlorides and arsenic can meet the use requirements of the isothermal shift reaction catalyst when performing isothermal shift reaction, thereby increasing the source range of the electric furnace tail gas. The processing method of the present application can be used for a wide range of electric furnace tail gas raw gas, and is suitable for electric furnace tail gas with high CO content and complex gas composition.

[0035] According to the present application, preferably, in S1, the pretreatment in the pretreated electric furnace tail gas refers to removing oil stains, dust and other substances in the electric furnace tail gas.

[0036] According to the present application, preferably, in S1, the first desulfurization is carried out in the presence of a first desulfurization catalyst; wherein the first desulfurizer is selected from at least one of COS hydrolysis desulfurizer, zinc oxide, copper-based desulfurizer and activated carbon, preferably at least one of zinc oxide, copper-based desulfurizer and activated carbon.

[0037] According to the present application, preferably, the process of the first desulfurization includes sequentially carrying out medium-temperature desulfurization, low-temperature desulfurization and fine desulfurization, wherein the medium-temperature desulfurization is carried out at a temperature of 175-190℃, a volume space velocity of the pretreated electric furnace tail gas is 1000-2000h -1 , the low-temperature desulfurization is carried out at a temperature of 160-175℃, a volume space velocity of the pretreated electric furnace tail gas is 1000-2000h -1 , and the fine desulfurization is carried out at a temperature of 175-185℃, a volume space velocity of the pretreated electric furnace tail gas is 1000-1500h -1 . The three-stage desulfurization is sequentially carried out under the above conditions, which can effectively remove sulfides in the pretreated electric furnace tail gas.

[0038] According to the present application, preferably, the content of sulfides in the desulfurized raw gas is less than or equal to 0.1ppm.

[0039] According to the present application, preferably, in S2, the first deoxidation is carried out in the presence of a first deoxidizer; wherein the first deoxidizer is selected from at least one of activated carbon, copper-based deoxidizer and molecular sieve, preferably copper-based deoxidizer. Using copper-based deoxidizer as the first deoxidizer can make the desulfurized raw gas have higher deoxidation efficiency.

[0040] According to the present application, preferably, the conditions of the first deoxidation include: a temperature of 175-180℃, a volume space velocity of the desulfurized raw gas is 1000-2000h -1The first deoxidation condition meets the range, which can effectively remove oxygen in the desulfurized raw gas.

[0041] According to the present application, preferably, the content of oxygen in the deoxidized raw gas is less than or equal to 0.05 Vol%.

[0042] According to the present application, preferably, in S3, the second desulfurization, the dechlorination, the dearsenication and the second deoxidation are respectively carried out in the presence of a second desulfurizer, a dechlorination agent, a dearsenication agent and a second deoxidation agent.

[0043] wherein,

[0044] The second desulfurizer is selected from a copper-based desulfurizer and / or activated carbon, preferably a copper-based desulfurizer;

[0045] The dechlorination agent is selected from at least one of a sodium-based dechlorination agent, a calcium-based dechlorination agent and a copper-based dechlorination agent, preferably a copper-based dechlorination agent;

[0046] The dearsenication agent is selected from a copper-based dearsenication agent and / or a manganese-based dearsenication agent, preferably a copper-based dearsenication agent;

[0047] The second deoxidation agent is selected from at least one of activated carbon, a copper-based deoxidation agent and a molecular sieve, preferably a copper-based deoxidation agent.

[0048] According to the present application, preferably, the volume ratio of water vapor to the deoxidized raw gas is (0.4-0.5):1.

[0049] According to the present application, preferably, the conditions of the purification treatment include: when the second desulfurization, the dechlorination, the dearsenication and the second deoxidation are carried out, the volume space velocity of the mixed gas of the deoxidized raw gas and water vapor is respectively 1000-2000 h -1 , 1000-2000 h -1 , 1000-2000 h -1 and 1000-1500 h -1 . The conditions of the purification treatment meet the range, which can further remove sulfides and oxides in the furnace tail gas, and has better dearsenication and dechlorination effects.

[0050] According to the present application, preferably, the content of sulfides in the shifted raw gas is less than or equal to 0.05 ppm, the content of oxygen is less than or equal to 0.02 Vol%, the concentration of chlorides is less than or equal to 0.01 ppm, and the concentration of arsenides is less than or equal to 0.005 ppm. The content of sulfides, oxygen, chlorides and arsenides in the shifted raw gas is reduced to the range, which can protect the isothermal shift reaction catalyst to operate stably for a long period.

[0051] According to the present application, in S4, the shift raw gas is subjected to an isothermal shift reaction with steam to convert CO in the shift raw gas into H2 and CO2. The gaseous phase product obtained by subjecting the shift raw gas to the isothermal shift reaction contains components such as CO, CO2, H2, N2 and CH4, and since it contains unreacted steam, the gaseous phase product needs to be subjected to condensation and gas-liquid separation to remove the unreacted steam, thereby obtaining a crude shift product gas; and then the obtained crude shift product gas is subjected to decarburization to remove CO2 produced in the isothermal shift reaction. Finally, a shift product gas mainly containing H2 after decarburization is obtained.

[0052] According to the present application, preferably, in S4, the isothermal shift reaction is carried out in the presence of an isothermal shift reaction catalyst; wherein the isothermal shift reaction catalyst is selected from a copper-based medium-temperature shift catalyst and / or a copper-based isothermal shift catalyst, preferably a copper-based isothermal shift catalyst.

[0053] According to the present application, preferably, the conditions of the isothermal shift reaction include that the volume space velocity of the shift raw gas is 1000-2000 h-1 and the bed temperature is 200-240℃. The conditions of the isothermal shift reaction meet the range, which can improve the conversion rate of CO in the shift raw gas, thereby reducing the content of CO in the gaseous phase product obtained after the isothermal shift reaction. -1

[0054] In the present application, the degree of the isothermal shift reaction can be controlled according to the amount of steam added in S3.

[0055] According to the present application, preferably, in S4, the content of CO in the gaseous phase product is 3-4.5 Vol%. The CO in the gaseous phase product is the unconverted CO in the shift raw gas. The content of CO in the gaseous phase product is 3-4.5 Vol%, which indicates that at the reaction temperature, the chemical reaction has reached equilibrium and CO cannot be completely converted.

[0056] According to the present application, preferably, in S5, the decarburization is carried out by using a temperature swing adsorption method (TSA), and the method of the decarburization includes that the crude shift product gas is subjected to adsorption and desorption by using an adsorbent; wherein the adsorbent is selected from at least one of silica gel, activated carbon and molecular sieve, preferably molecular sieve. The temperature swing adsorption method (TSA) can effectively adsorb CO2 in the gas. The content of CO2 in the shift product gas after decarburization can be controlled by controlling the degree of adsorption. The molecular sieve as the adsorbent can achieve good adsorption effect.

[0057] According to the present application, preferably, the conditions of the decarburization include that the adsorption temperature is 20-30℃ and the desorption temperature is 115-125℃.

[0058] ​According to the application, preferably, the content of CO2 in the decarburized shift product gas is less than or equal to 5 Vol%, the content of CO is 5.5-8.5 Vol%, the content of H2 is 70.5-73.5 Vol%, the content of N2 is 14.5-16 Vol%, and the content of CH4 is 0.03-0.04 Vol%.

[0059] The second aspect of the application provides a device for treating electric furnace tail gas, comprising, in sequence, a pretreatment furnace, a desulfurization unit, a deoxidation furnace, a purification furnace, an isothermal shift reaction furnace, a gas-liquid separation unit and a temperature swing adsorption tower; wherein,

[0060] The pretreatment furnace is used for pretreating the electric furnace tail gas to remove oil stains and dust, thereby obtaining pretreated electric furnace tail gas;

[0061] The desulfurization unit is used for first desulfurizing the pretreated electric furnace tail gas, thereby obtaining desulfurized raw gas;

[0062] The deoxidation furnace is used for first deoxidizing the desulfurized raw gas, thereby obtaining deoxidized raw gas;

[0063] The purification furnace is filled with desulfurizing agent, dechlorinating agent, dearsenizing agent and deoxidizing agent, and is used for second desulfurizing, dechlorinating, dearsenizing and second deoxidizing the deoxidized raw gas, thereby obtaining shift raw gas;

[0064] The isothermal shift reaction furnace is used for isothermal shift reaction of the shift raw gas, converting CO in the shift raw gas into H2 and CO2;

[0065] The gas-liquid separation unit comprises a water cooling system and a gas-liquid separator, and is used for condensing and gas-liquid separating the gaseous phase product obtained by the isothermal shift reaction, and the obtained crude shift product gas flows out from the upper part of the gas-liquid separator;

[0066] The temperature swing adsorption tower is used for removing CO2 in the crude shift product gas.

[0067] According to the application, preferably, the desulfurization unit comprises, in sequence, a medium-temperature desulfurization furnace, a low-temperature desulfurization furnace and a fine desulfurization furnace, and the medium-temperature desulfurization furnace, the low-temperature desulfurization furnace and the fine desulfurization furnace are all filled with desulfurizing agent; wherein,

[0068] The temperature in the medium-temperature desulfurization furnace is 175-190℃, the temperature in the low-temperature desulfurization furnace is 160-175℃, and the temperature in the fine desulfurization furnace is 175-185℃.

[0069] According to the application, preferably, the deoxidation furnace is filled with deoxidizing agent.

[0070] According to the present application, preferably, the inner wall of the purifying furnace is provided with an annular jacket, and circulating water is filled in the jacket, and the water flows from top to bottom.

[0071] According to the present application, preferably, the purifying furnace is filled with desulfurizing agent, dechlorinating agent, dearsenizing agent and deoxidizing agent from top to bottom.

[0072] According to the present application, preferably, the isothermal shift reaction furnace is filled with isothermal shift reaction catalyst.

[0073] According to the present application, preferably, the isothermal shift reaction furnace is a radial bed. The shift gas raw gas enters the reaction furnace from the upper part, passes through the catalyst bed from outside to inside in the cavity close to the outer wall, and then leaves the reaction furnace from the lower part of the middle tube.

[0074] According to the present application, preferably, the isothermal shift reaction furnace is provided with a lower hanging water jacket, which is connected with a steam drum for taking away the heat generated in the reaction.

[0075] According to a preferred embodiment of the present application, the process for treating electric furnace tail gas comprises the following steps: Figure 1 The process for treating electric furnace tail gas is described.

[0076] The electric furnace tail gas raw gas is pre-treated in a pre-treating furnace to remove oil stains, dust and other substances, and the pre-treated electric furnace tail gas is obtained. Then, the pre-treated electric furnace tail gas is sequentially subjected to desulfurization in a medium-temperature desulfurization furnace, a low-temperature desulfurization furnace and a fine desulfurization furnace, and the desulfurized raw gas is obtained. Then, the desulfurized raw gas is subjected to deoxidization in a deoxidization furnace, and the deoxidized raw gas is mixed with water vapor and subjected to desulfurization, dechlorination, dearsenization and deoxidization in a purifying furnace in sequence, and the shift raw gas is obtained. The shift raw gas is subjected to isothermal shift reaction in an isothermal shift reaction furnace, and CO in the shift raw gas is converted into H2 and CO2. The gas phase product flowing out of the isothermal shift reaction furnace is first cooled by a water cooling system, and then subjected to gas-liquid separation, and the crude shift product gas is obtained and flows out of the upper part of the separator. The crude shift product gas is subjected to TSA adsorption in a TSA adsorption tower, and CO2 in the crude shift product gas is removed, and the decarburized shift product gas is obtained.

[0077] In the present application, ppm is mg / m 3 .

[0078] The present application will be described in detail by way of examples and comparative examples. In the following examples, all the methods are conventional methods unless otherwise specified, and all the reagents and materials are commercially available unless otherwise specified.

[0079] The gas content is determined by gas chromatography according to the internal standard method.

[0080] The following examples are used to illustrate the method for treating electric furnace tail gas.

[0081] Example 1

[0082] The electric furnace tail gas raw material gas is electric furnace tail gas of an iron alloy factory, wherein the content of hydrogen is 5.6 Vol%, the content of carbon monoxide is 63.7 Vol%, the content of carbon dioxide is 15.2 Vol%, the content of nitrogen is 15.4 Vol%, the content of methane is 0.02 Vol%, the content of oxygen is 0.05 Vol%, the content of sulfide is 0.15 ppm, the content of chloride is 0.1 ppm, and the content of arsenide is 0.005 ppm.

[0083] The specific steps for processing the electric furnace tail gas are as follows:

[0084] (1) Pretreatment and desulfurization: the electric furnace tail gas raw material gas is passed through a pretreatment furnace to remove oil stains, dust and other substances to obtain pretreated electric furnace tail gas; then the pretreated electric furnace tail gas is sequentially passed through a medium-temperature desulfurization furnace, a low-temperature desulfurization furnace and a fine desulfurization furnace, the medium-temperature desulfurization reaction temperature is controlled at 185°C, the low-temperature desulfurization reaction temperature is controlled at 170°C, and the fine desulfurization reaction temperature is controlled at 175°C to obtain desulfurized raw material gas with a sulfide concentration of 0.07 ppm; wherein,

[0085] The medium-temperature desulfurization furnace, the low-temperature desulfurization furnace and the fine desulfurization furnace are respectively filled with zinc oxide desulfurizer T-308, activated carbon desulfurizer HT-102 and copper-based desulfurizer K-806; the volume space velocities of the pretreated electric furnace tail gas in the medium-temperature desulfurization furnace, the low-temperature desulfurization furnace and the fine desulfurization furnace are respectively 2000h -1 , 2000h -1 and 1500h -1 ;

[0086] (2) Deoxidation: the desulfurized raw material gas is passed through a deoxidation furnace, the deoxidation furnace reaction temperature is controlled at 180°C to obtain deoxidized raw material gas with an oxygen content of 0.035 Vol%; wherein, the deoxidation furnace is filled with copper-based deoxidizer Z-30, and the volume space velocity of the desulfurized raw material gas is 2000h -1 ;

[0087] (3) Purification: the deoxidized raw material gas is mixed with steam in a volume ratio of 0.4:1 and passed through a purification furnace to sequentially remove sulfides, chlorides, arsenides and oxygen to obtain shift raw material gas with a sulfide concentration of 0.03 ppm, an oxygen concentration of 0%, a chloride concentration of 0.005 ppm and an arsenide concentration of 0 ppm; wherein,

[0088] The purification furnace is sequentially filled from top to bottom with copper-based desulfurizer K-102, copper-based dechlorination agent JX-5, copper-based arsenic removal agent 9801 and copper-based deoxidizer AZ-1; the volume space velocities of the mixed gas of the deoxidized raw material gas and steam are respectively 2000h -1 , 2000h -1 , 2000h -1 and 1500h-1 ;

[0089] (4) isothermal shift and gas-liquid separation: the shifted raw gas is cooled by a water cooling system and then separated into gas and liquid, and the crude shifted product gas is obtained from the upper part of the separator; wherein the CO content at the outlet of the isothermal shift reactor is 3.2 Vol%; wherein,

[0090] The isothermal shift reactor is filled with copper-based isothermal shift catalyst B209, and the volume space velocity of the shifted raw gas is 2000h -1 -1; and the bed temperature is 220℃;

[0091] (5) decarburization: the crude shifted product gas is decarburized at an adsorption temperature of 25℃ and a desorption temperature of 120℃ in a TSA adsorption tower, and the decarburized shifted product gas with a CO2 content of 4.5 Vol%, a CO content of 7.4 Vol%, a H2 content of 73.5 Vol%, a N2 content of 14.5 Vol% and a CH4 content of 0.03 Vol% is obtained; wherein the TSA adsorption tower is filled with molecular sieve adsorbent 13XAPG.

[0092] Example 2

[0093] The raw gas of the electric furnace tail gas is an electric furnace tail gas from a ferroalloy plant, wherein the content of hydrogen is 4.6 Vol%, the content of carbon monoxide is 66.7 Vol%, the content of carbon dioxide is 13.2 Vol%, the content of nitrogen is 15.4 Vol%, the content of methane is 0.025 Vol%, the content of oxygen is 0.03 Vol%, the content of sulfide is 0.14 ppm, the content of chloride is 0.1 ppm, and the content of arsenide is 0.002 ppm.

[0094] The specific steps for processing the electric furnace tail gas are as follows:

[0095] (1) pretreatment and desulfurization: the raw gas of the electric furnace tail gas is pretreated by a pretreatment furnace to remove oil stains, dust and other substances, and the pretreated electric furnace tail gas is then sequentially passed through a medium-temperature desulfurization furnace, a low-temperature desulfurization furnace and a fine desulfurization furnace, and the medium-temperature desulfurization reaction temperature is controlled at 190℃, the low-temperature desulfurization reaction temperature is controlled at 175℃, and the fine desulfurization reaction temperature is controlled at 180℃, and the desulfurized raw gas with a sulfide concentration of 0.06 ppm is obtained; wherein,

[0096] The medium-temperature desulfurization furnace, the low-temperature desulfurization furnace and the fine desulfurization furnace are respectively filled with zinc oxide desulfurizer K-101, activated carbon desulfurizer HT-102 and copper-based desulfurizer K-806; and the volume space velocities of the pretreated electric furnace tail gas in the medium-temperature desulfurization furnace, the low-temperature desulfurization furnace and the fine desulfurization furnace are respectively 1500h -1 -1, 1500h -1 -1 and 1500h-1 ;

[0097] (2) Deoxidation: The desulfurized feed gas passes through a deoxidation furnace, and the reaction temperature of the deoxidation furnace is controlled at 175°C to obtain deoxidized feed gas with an oxygen concentration of 0.02 Vol%; wherein, the deoxidation furnace is filled with copper-based deoxidizer Z-30, and the volume space velocity of the desulfurized feed gas is 1500h -1 ;

[0098] (3) Purification: The deoxidized feed gas is mixed with steam in a volume ratio of 0.45:1, and then passes through a purification furnace in turn for desulfurization, dechlorination, dearsenization and deoxidation to obtain shift feed gas with a sulfide concentration of 0.02 ppm, an oxygen concentration of 0%, a chloride concentration of 0.002 ppm and an arsenic content of 0 ppm; wherein,

[0099] The purification furnace is filled from top to bottom with copper-based desulfurizer K-102, copper-based dechlorination agent JX-5, copper-based dearsenization agent 9803 and copper-based deoxidation agent AZ-1; the volume space velocity of the mixed gas of the deoxidized feed gas and steam is 1500h -1 , 1500h -1 , 1500h -1 and 1200h -1 ;

[0100] (4) Isothermal shift and gas-liquid separation: the shift feed gas passes through an isothermal shift reactor, and the gas phase product flowing out of the isothermal shift reactor is first cooled by a water cooling system and then separated to obtain crude shift product gas flowing out from the upper part of the separator; wherein, the CO content at the outlet of the isothermal shift reactor is 4.1 Vol%; wherein,

[0101] The isothermal shift reactor is filled with copper-based isothermal shift catalyst B210, and the volume space velocity of the shift feed gas is 1500h -1 , and the bed temperature is 200°C;

[0102] (5) Decarburization: the crude shift product gas passes through a TSA adsorption tower with an adsorption temperature of 20°C and a desorption temperature of 115°C to obtain decarburized shift product gas with a CO2 content of 4.4 Vol%, a CO content of 7.2 Vol%, a H2 content of 73.5 Vol%, a N2 content of 14.5 Vol% and a CH4 content of 0.03 Vol%; wherein, the TSA adsorption tower is filled with molecular sieve adsorbent 13XAPG.

[0103] Example 3

[0104] The electric furnace tail gas raw material gas is electric furnace tail gas of an iron alloy factory, wherein the content of hydrogen is 4.4 Vol%, the content of carbon monoxide is 67.8 Vol%, the content of carbon dioxide is 12.8 Vol%, the content of nitrogen is 14.9 Vol%, the content of methane is 0.025 Vol%, the content of oxygen is 0.04 Vol%, the content of sulfide is 0.12 ppm, the content of chloride is 0.06 ppm, and the content of arsenide is 0.004 ppm.

[0105] The specific steps for processing the electric furnace tail gas are as follows:

[0106] (1) Pretreatment and desulfurization: the electric furnace tail gas raw material gas is passed through a pretreatment furnace to remove oil stains, dust and other substances to obtain pretreated electric furnace tail gas; then the pretreated electric furnace tail gas is sequentially passed through a medium-temperature desulfurization furnace, a low-temperature desulfurization furnace and a fine desulfurization furnace, the medium-temperature desulfurization reaction temperature is controlled at 185℃, the low-temperature desulfurization reaction temperature is controlled at 170℃, and the fine desulfurization reaction temperature is controlled at 180℃, to obtain desulfurized raw material gas with a sulfide concentration of 0.04 ppm; wherein,

[0107] The medium-temperature desulfurization furnace, the low-temperature desulfurization furnace and the fine desulfurization furnace are respectively filled with zinc oxide desulfurizer K-101, copper-based desulfurizer K-806 and activated carbon desulfurizer T-205; the volume space velocity of the pretreated electric furnace tail gas in the medium-temperature desulfurization furnace, the low-temperature desulfurization furnace and the fine desulfurization furnace is respectively 1200h -1 , 1300h -1 and 1500h -1 ;

[0108] (2) Deoxidation: the desulfurized raw material gas is passed through a deoxidation furnace, the deoxidation furnace reaction temperature is controlled at 175℃, to obtain deoxidized raw material gas with an oxygen content of 0.01 Vol%; wherein, the deoxidation furnace is filled with copper-based deoxidizer Z-30, and the volume space velocity of the desulfurized raw material gas is 1500h -1 ;

[0109] (3) Purification: the deoxidized raw material gas is mixed with steam in a volume ratio of 0.5:1 and passed through a purification furnace to sequentially remove sulfides, chlorides, arsenides and oxygen to obtain shift raw material gas with a sulfide concentration of 0.02 ppm, an oxygen concentration of 0%, a chloride concentration of 0.001 ppm and an arsenide content of 0 ppm; wherein,

[0110] The purification furnace is sequentially filled from top to bottom with copper-based desulfurizer K-102, copper-based dechlorination agent JX-5, copper-based arsenic removal agent 9803 and copper-based deoxidizer AZ-1; the volume space velocity of the mixed gas of the deoxidized raw material gas and steam is 1000h -1 ;

[0111] (4) isothermal shift and gas-liquid separation: the shifted feed gas is cooled by a water cooling system and then separated into gas and liquid, and the crude shifted product gas is obtained from the top of the separator; wherein the CO content at the outlet of the isothermal shift reactor is 3.5 Vol%; wherein,

[0112] The isothermal shift reactor is filled with copper-based isothermal shift catalyst B210, and the volume space velocity of the shifted feed gas is 1200h -1 -1; the bed temperature is 240°C;

[0113] (5) decarburization: the adsorption temperature of the TSA adsorption tower is controlled at 30°C, and the desorption temperature is controlled at 125°C; the crude shifted product gas is passed through the TSA adsorption tower to obtain a decarburized shifted product gas with a CO2 content of 4.5 Vol%, a CO content of 8.2 Vol%, a H2 content of 72.7 Vol%, a N2 content of 14.5 Vol%, and a CH4 content of 0.03 Vol%; wherein the TSA adsorption tower is filled with molecular sieve adsorbent 13XAPG.

[0114] Example 4

[0115] The electric furnace tail gas is treated according to the method of Example 1, except that in step (1), the desulfurized feed gas with a sulfide concentration of 0.12 ppm is obtained without passing through the medium-temperature desulfurization reactor; further, the desoxidized feed gas with an oxygen content of 0.04 Vol% is obtained; the shifted feed gas with a sulfide concentration of 0.065 ppm, an oxygen concentration of 0%, a chloride concentration of 0.005 ppm, and an arsenic chloride concentration of 0.005 ppm is obtained; the CO content at the outlet of the isothermal shift reactor is 5.5 Vol%; finally, the decarburized shifted product gas with a CO2 content of 4.5 Vol%, a CO content of 10.4 Vol%, a H2 content of 69.5 Vol%, a N2 content of 14.5 Vol%, and a CH4 content of 0.03 Vol% is obtained.

[0116] Example 5

[0117] The electric furnace tail gas was treated according to the method of Example 1, except that in step (1), the medium temperature desulfurization reaction temperature was controlled at 195°C, the low temperature desulfurization reaction temperature was controlled at 155°C, and the fine desulfurization reaction temperature was controlled at 170°C, to obtain a desulfurized raw material gas with a sulfide concentration of 0.19 ppm; further to obtain a deoxidized raw material gas with an oxygen content of 0 Vol%; to obtain a shift raw material gas with a sulfide concentration of 0.07 ppm, an oxygen concentration of 0%, a chloride concentration of 0.004 ppm, and an arsenide concentration of 0.004 ppm; a CO content at the outlet of the isothermal shift converter of 6.9 Vol%; and finally to obtain a decarburized shift product gas with a CO2 content of 4.3 Vol%, a CO content of 12.5 Vol%, an H2 content of 68.2 Vol%, an N2 content of 14.9 Vol%, and a CH4 content of 0.03 Vol%.

[0118] Example 6

[0119] The electric furnace tail gas was treated according to the method of Example 1, except that in step (2), the deoxidation furnace reaction temperature was controlled at 185°C, to obtain a deoxidized raw material gas with an oxygen content of 0.085 Vol%; to obtain a shift raw material gas with a sulfide concentration of 0.09 ppm, an oxygen content of 0.04 Vol%, a chloride concentration of 0.004 ppm, and an arsenide concentration of 0.004 ppm; a CO content at the outlet of the isothermal shift converter of 5.5 Vol%; and finally to obtain a decarburized shift product gas with a CO2 content of 4.5 Vol%, a CO content of 11.5 Vol%, an H2 content of 69.1 Vol%, an N2 content of 14.8 Vol%, and a CH4 content of 0.04 Vol%.

[0120] Example 7

[0121] The electric furnace tail gas was treated according to the method of Example 1, except that the composition of the electric furnace tail gas feed gas was different. Specifically, the carbon monoxide content was 60.7 Vol%, the hydrogen content was 4.6 Vol%, the carbon dioxide content was 20.2 Vol%, the nitrogen content was 14.4 Vol%, the methane content was 0.02 Vol%, the oxygen content was 0.04 Vol%, the sulfide content was 0.14 ppm, the chloride content was 0.1 ppm, and the arsenic content was 0.005 ppm. A desulfurized feed gas having a sulfide concentration of 0.06 ppm was obtained; a deoxygenated feed gas having an oxygen concentration of 0.01 Vol% was further obtained; a shifted feed gas having a sulfide concentration of 0.05 ppm, an oxygen content of 0.005%, a chloride concentration of 0.004 ppm, and an arsenic concentration of 0.004 ppm was obtained; the CO content at the outlet of the isothermal shift converter was 6 Vol%; and finally a decarbonized shifted product gas having a CO2 content of 5.9 Vol%, a CO content of 10.5 Vol%, an H2 content of 68.8 Vol%, an N2 content of 14.7 Vol%, and a CH4 content of 0.03 Vol% was obtained.

[0122] Example 8

[0123] The electric furnace tail gas was treated according to the method of Example 1, except that the bed temperature of the isothermal shift reactor was 250°C. The CO content at the outlet of the isothermal shift converter was 4.9 Vol%; and finally a decarbonized shifted product gas having a CO2 content of 4.4 Vol%, a CO content of 10.5 Vol%, an H2 content of 70.2 Vol%, an N2 content of 14.5 Vol%, and a CH4 content of 0.03 Vol% was obtained.

[0124] Example 9

[0125] The electric furnace tail gas was treated according to the method of Example 1, except that the COS hydrolysis desulfurizer T503 was used instead of the zinc oxide desulfurizer in the medium-temperature desulfurizer. A desulfurized feed gas having a sulfide concentration of 0.23 ppm was obtained; a deoxygenated feed gas having an oxygen content of 0.035 Vol% was further obtained; a shifted feed gas having a sulfide concentration of 0.13 ppm, an oxygen concentration of 0%, a chloride concentration of 0.005 ppm, and an arsenic chloride concentration of 0 ppm was obtained; the CO content at the outlet of the isothermal shift converter was 5.8 Vol%; and finally a decarbonized shifted product gas having a CO2 content of 4.5 Vol%, a CO content of 14.9 Vol%, an H2 content of 64.5 Vol%, an N2 content of 15.9 Vol%, and a CH4 content of 0.03 Vol% was obtained.

[0126] Example 10

[0127] The electric furnace tail gas was treated according to the method of Example 1, except that activated carbon deoxidizer T3093 was used instead of copper deoxidizer in the deoxidizing furnace. The deoxidized raw gas with an oxygen content of 0.12 Vol% was obtained; the shift raw gas with a sulfide concentration of 0.03 ppm, an oxygen concentration of 0.07 Vol%, a chloride concentration of 0.005 ppm and an arsenic chloride concentration of 0 ppm was obtained; the CO content at the outlet of the isothermal shift furnace was 5.9 Vol%; and finally the decarburized shift product gas with a CO2 content of 4.5 Vol%, a CO content of 14.4 Vol%, an H2 content of 66.1 Vol%, an N2 content of 14.9 Vol% and a CH4 content of 0.02 Vol% was obtained.

[0128] Example 11

[0129] The electric furnace tail gas was treated according to the method of Example 1, except that activated carbon desulfurizer T205, sodium dechlorination agent F-101, manganese dearsenic agent JT-2 and molecular sieve deoxidizer F-02 were sequentially loaded from top to bottom in the purification furnace. The shift raw gas with a sulfide concentration of 0.11 ppm, an oxygen concentration of 0.05%, a chloride concentration of 0.03 ppm and an arsenic chloride concentration of 0 ppm was obtained; the CO content at the outlet of the isothermal shift furnace was 6.2 Vol%; and finally the decarburized shift product gas with a CO2 content of 4.9 Vol%, a CO content of 13.2 Vol%, an H2 content of 67.2 Vol%, an N2 content of 14.6 Vol% and a CH4 content of 0.03 Vol% was obtained.

[0130] Example 12

[0131] The electric furnace tail gas was treated according to the method of Example 1, except that activated carbon adsorbent HT-111 was used instead of molecular sieve adsorbent in the TSA adsorption tower. Finally, the decarburized shift product gas with a CO2 content of 5.3 Vol%, a CO content of 7.4 Vol%, an H2 content of 71.5 Vol%, an N2 content of 15.5 Vol% and a CH4 content of 0.02 Vol% was obtained.

[0132] Example 13

[0133] The electric furnace tail gas was treated according to the method of Example 1, except that the adsorption temperature of the TSA adsorption tower was controlled at 35°C and the desorption temperature was controlled at 130°C during decarburization. Finally, the decarburized shift product gas with a CO2 content of 5.6 Vol%, a CO content of 7.4 Vol%, an H2 content of 72.4 Vol%, an N2 content of 14.5 Vol% and a CH4 content of 0.03 Vol% was obtained.

[0134] Comparative Example 1

[0135] The electric furnace tail gas was treated according to the method of Example 1, except that the pretreated electric furnace tail gas was first subjected to first deoxidation to obtain a deoxidized raw gas, and then the deoxidized raw gas was subjected to first desulfurization to obtain a desulfurized raw gas. The deoxidized raw gas with an oxygen content of 0.09 Vol% was obtained, and then the desulfurized raw gas with a sulfide concentration of 0.28 ppm was obtained; the shift raw gas with a sulfide concentration of 0.12 ppm, an oxygen concentration of 0.04%, a chloride concentration of 0.09 ppm and an arsenide concentration of 0.01 ppm was obtained; the CO content at the outlet of the isothermal shift converter was 8.5 Vol%; and finally the decarburized shift product gas with a CO2 concentration of 4.9 Vol%, a CO content of 19.5 Vol%, an H2 content of 59 Vol%, an N2 content of 14.5 Vol% and a CH4 content of 0.04 Vol% was obtained.

[0136] As can be seen from the results of the examples and comparative examples, the CO2 content in the decarburized shift product gas obtained in Examples 1-13 is less than or equal to 6 Vol%, the CO content is 15 Vol% or less, and the H2 content is 64 Vol% or more, indicating that the electric furnace tail gas treated by the method of the present application can reduce the emission of carbon dioxide gas and achieve efficient use of the electric furnace tail gas, so that the CO in the electric furnace tail gas has a relatively high conversion rate.

[0137] In addition, the first desulfurization of Example 4 does not pass through a medium-temperature desulfurization furnace, the first desulfurization of Example 5 is raised in temperature, and the desulfurizer in the medium-temperature desulfurization furnace of Example 9 is changed. Compared with Example 1, the sulfide concentration in the shift raw gas obtained by Example 4, Example 5 and Example 9 is higher, and the CO content and the H2 content in the decarburized shift product gas obtained finally are higher and lower, respectively. The reaction temperature of the deoxidizer furnace of Example 6 is raised, and the deoxidizer in the deoxidizer furnace of Example 10 is changed. Compared with Example 1, the sulfide and oxygen concentrations in the shift raw gas obtained by Example 6 are higher, and the oxygen concentration in the shift raw gas obtained by Example 10 is higher. The CO content and the H2 content in the decarburized shift product gas obtained finally by Example 6 and Example 10 are higher and lower, respectively. The composition of the raw gas of the electric furnace tail gas is changed in Example 7, and the bed temperature of the isothermal shift reactor is raised in Example 8. Compared with Example 1, the CO content and the H2 content in the decarburized shift product gas obtained finally by Example 7 and Example 8 are higher and lower, respectively. The types of the desulfurizer, the dechlorinizer, the dearsenizer and the deoxidizer in the purifying furnace are changed in Example 11. Compared with Example 1, the sulfide, oxygen and chloride concentrations in the shift raw gas obtained are all increased, and the CO content and the H2 content in the decarburized shift product gas obtained finally are higher and lower, respectively. The type of the adsorbent in the TSA adsorption tower is changed in Example 12, and the adsorption and desorption temperatures are changed in Example 13. Compared with Example 1, the CO2 content in the decarburized shift product gas obtained finally is increased. The above results show that the mode, condition and type of the first desulfurization, the condition and type of the first deoxidization, the types of the desulfurizer, the dechlorinizer, the dearsenizer and the deoxidizer during purification, the composition of the raw gas of the electric furnace tail gas and the isothermal shift reaction condition all have great influences on the composition of the shift raw gas, thereby affecting the CO conversion rate. The type and condition of the adsorbent during decarburization affect the carbon dioxide emission.

[0138] The above describes the preferred embodiments of the present application in detail, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications of the technical solutions of the present application can be made, including the combination of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as disclosed by the present application and fall within the protection scope of the present application.

Claims

1. A method of treating an electric arc furnace off-gas, characterized in that, The method comprises the following steps: S1, carrying out first desulfurization on the pretreated electric furnace tail gas to obtain a desulfurized raw gas; S2, carrying out first deoxygenation on the desulfurized raw gas to obtain a deoxygenated raw gas; S3, mixing the deoxygenated raw gas with water vapor to carry out purification treatment to obtain a shift raw gas; wherein, the purification treatment comprises second desulfurization, dechlorination, dearsenization and second deoxygenation; S4, carrying out isothermal shift reaction on the shift raw gas, and carrying out condensation and gas-liquid separation on the obtained gas phase product; S5, carrying out decarburization on the crude shift product gas obtained by the gas-liquid separation to obtain a decarburized shift product gas; The content of CO in the electric furnace tail gas is 60-75 Vol%, the content of hydrogen is 3-6 Vol%, the content of carbon dioxide is 11-16 Vol%, the content of nitrogen is 12-16 Vol%, the content of methane is 0.01-0.03 Vol%, the content of oxygen is 0.02-0.08 Vol%, the content of sulfide is less than or equal to 0.15 ppm, the content of chloride is less than or equal to 0.15 ppm, and the content of arsenide is less than or equal to 0.01 ppm; In S1, the first desulfurization is carried out in the presence of a first desulfurization agent; wherein, the first desulfurization agent is selected from at least one of COS hydrolysis desulfurization agent, zinc oxide, copper-based desulfurization agent and activated carbon; The first desulfurization process comprises: sequentially performing medium-temperature desulfurization, low-temperature desulfurization and fine desulfurization, wherein the medium-temperature desulfurization is performed at a temperature of 175-190 DEG C, a volume space velocity of the pre-processed electric furnace tail gas is 1000-2000 h -1 -1; the low-temperature desulfurization is performed at a temperature of 160-175 DEG C, a volume space velocity of the pre-processed electric furnace tail gas is 1000-2000 h -1 -1; and the fine desulfurization is performed at a temperature of 175-185 DEG C, a volume space velocity of the pre-processed electric furnace tail gas is 1000-1500 h -1 -1. The content of sulfide in the desulfurized raw gas is less than or equal to 0.1 ppm; In S3, the second desulfurization, the dechlorination, the dearsenization and the second deoxygenation are carried out in the presence of a second desulfurization agent, a dechlorination agent, a dearsenization agent and a second deoxygenation agent, respectively; wherein, The second desulfurization agent is selected from copper-based desulfurization agent and / or activated carbon; The dechlorination agent is selected from at least one of sodium-based dechlorination agent, calcium-based dechlorination agent and copper-based dechlorination agent; The dearsenization agent is selected from copper-based dearsenization agent and / or manganese-based dearsenization agent; The second deoxygenation agent is selected from at least one of activated carbon, copper-based deoxygenation agent and molecular sieve; The volume ratio of water vapor to the deoxygenated raw gas is (0.4-0.5):1; The conditions of the purification treatment include: the volume space velocity of the mixed gas of the deoxidation raw material gas and water vapor is 1000-2000 h -1 , 1000-2000 h -1 , 1000-2000 h -1 , and 1000-1500 h -1 , respectively, when the second desulfurization, the dechlorination, the dearsenication, and the second deoxidation are performed. The concentration of sulfide in the shift raw gas is less than or equal to 0.05 ppm, the content of oxygen is less than or equal to 0.02 Vol%, the concentration of chloride is less than or equal to 0.01 ppm, and the concentration of arsenide is less than or equal to 0.005 ppm.

2. The method of claim 1, wherein, The first desulfurization agent is at least one of zinc oxide, copper-based desulfurization agent and activated carbon.

3. The method of claim 1 or 2, wherein, In S2, the first deoxygenation is carried out in the presence of a first deoxygenation agent; wherein, the first deoxygenation agent is selected from at least one of activated carbon, copper-based deoxygenation agent and molecular sieve.

4. The method of claim 3, wherein, The first deoxygenation agent is copper-based deoxygenation agent.

5. The method of claim 3, wherein, The first deoxidation conditions include: temperature is 175-180℃, the volume space velocity of the desulfurization raw gas is 1000-2000h -1 .

6. The method of claim 3, wherein, The content of oxygen in the deoxygenated raw gas is less than or equal to 0.05 Vol%.

7. The method of claim 1 or 2, wherein, The second desulfurization agent is copper-based desulfurization agent.

8. The method of claim 1 or 2, wherein, The dechlorination agent is copper-based dechlorination agent.

9. The method of claim 1 or 2, wherein, The dearsenization agent is copper-based dearsenization agent.

10. The method of claim 1 or 2, wherein, The second deoxygenation agent is copper-based deoxygenation agent.

11. The method of claim 1 or 2, wherein, In S4, the isothermal shift reaction is carried out in the presence of an isothermal shift reaction catalyst; wherein, the catalyst is selected from copper-based medium-temperature shift catalyst and / or copper-based isothermal shift catalyst.

12. The method of claim 11, wherein, The catalyst is copper-based isothermal shift catalyst.

13. The method of claim 11, wherein, The conditions of the isothermal shift reaction include a volume space velocity of the shift raw material gas of 1000-2000 h -1 , and a bed temperature of 200-240°C.

14. The method of claim 11, wherein, In S4, the CO content in the gas phase product is 3-4.5 Vol%.

15. The method of claim 1 or 2, wherein, In S5, the decarburization method comprises: adsorbing and desorbing the crude shift product gas with an adsorbent; wherein the adsorbent is selected from at least one of silica gel, activated carbon and molecular sieve.

16. The method of claim 15, wherein, The adsorbent is molecular sieve.

17. The method of claim 15, wherein, The decarburization conditions comprise: the adsorption temperature is 20-30℃, and the desorption temperature is 115-125℃.

18. The method of claim 15, wherein, After decarburization, the CO2 content in the shift product gas is less than or equal to 5 Vol%, the CO content is 5.5-8.5 Vol%, the H2 content is 70.5-73.5 Vol%, the N2 content is 14.5-16 Vol%, and the CH4 content is 0.03-0.04 Vol%.

19. An apparatus for treating an electric arc furnace off-gas according to the method of any one of claims 1-18, wherein, The device comprises, in sequence, a pretreatment furnace, a desulfurization unit, a deoxygenation furnace, a purification furnace, an isothermal shift reaction furnace, a gas-liquid separation unit and an adsorption tower; wherein, The pretreatment furnace is used for pretreating the electric furnace tail gas to remove oil stains and dust, thereby obtaining pretreated electric furnace tail gas; The desulfurization unit is used for first desulfurizing the pretreated electric furnace tail gas, thereby obtaining desulfurized raw gas; The deoxygenation furnace is used for first deoxygenating the desulfurized raw gas, thereby obtaining deoxygenated raw gas; The purification furnace is filled with desulfurizing agent, dechlorinating agent, dearsenizing agent and deoxidizing agent, and is used for second desulfurizing, dechlorinating, dearsenizing and second deoxygenating the deoxygenated raw gas, thereby obtaining shift raw gas; The isothermal shift reaction furnace is used for isothermal shift reaction of the shift raw gas, converting CO in the shift raw gas into H2 and CO2; The gas-liquid separation unit comprises a water cooling system and a gas-liquid separator, and is used for condensing and gas-liquid separating the gas phase product obtained by isothermal shift reaction; The adsorption tower is used for removing CO2 in the crude shift product gas.

20. The apparatus of claim 19, wherein, The desulfurization unit comprises, in sequence, a medium-temperature desulfurization furnace, a low-temperature desulfurization furnace and a fine desulfurization furnace; wherein, The temperature in the medium-temperature desulfurization furnace is 175-190℃, the temperature in the low-temperature desulfurization furnace is 160-175℃, and the temperature in the fine desulfurization furnace is 175-185℃.

21. The apparatus of claim 19 or 20, wherein, The inner wall of the purification furnace is provided with an annular sleeve, and the sleeve is filled with circulating water.

22. The apparatus of claim 21, wherein, The purification furnace is filled with desulfurizing agent, dechlorinating agent, dearsenizing agent and deoxidizing agent from top to bottom.

23. The apparatus of any of claims 19-22, wherein, The isothermal shift reaction furnace is filled with isothermal shift reaction catalyst.

24. The apparatus of claim 23, wherein, The isothermal shift reaction furnace is a radial bed.

25. The apparatus of claim 23, wherein, The isothermal shift reaction furnace is provided with a lower hanging water jacket, which is connected with a steam drum and is used for carrying away the heat generated by reaction.

Images