System and method for recovering carbon dioxide and carbon monoxide from steel by-product gas

Abstract

A system for recovering carbon dioxide and carbon monoxide from steel by-product gas according to the present invention comprises: a pretreatment unit (100) for producing refined by-product gas by removing impurities in the steel by-product gas; a carbon dioxide recovery unit (200) which selectively separates carbon dioxide in the refined by-product gas to produce carbon dioxide-free refined by-product gas and recovers the separated carbon dioxide; and a carbon monoxide recovery unit (300) for recovering carbon monoxide in the carbon dioxide-free refined by-product gas, wherein the pretreatment unit (100) comprises a separation tower (110), a dust collector (120), an adsorption tower (130), and a catalyst tower (140), and the catalyst tower (140) can remove 99 vol% or more of oxygen in the steel by-product gas.

Description

System and method for recovering carbon dioxide and carbon monoxide from by-product gas of steelmaking

[0001] The present invention relates to a system and method for recovering carbon dioxide and carbon monoxide from by-product gas of a steel mill.

[0002]

[0003] By-product gas from the steelmaking process has generally been used primarily in downstream processes, primarily as a fuel for heating purposes or for generating electricity.

[0004] Recently, efforts are being made to separate and purify the byproduct gas to increase value and reuse it for purposes other than its original purpose. Steelmaking byproduct gas can be further enhanced through various methods, including catalytic processes. For example, it can be converted into high-calorific fuel or into basic chemical products such as carbon monoxide, hydrogen, or other chemical products.

[0005] Therefore, it is necessary to develop a technology to efficiently separate effective components in the by-product gas of the steelmaking process.

[0006] In one embodiment of the present invention, a system and method for efficiently recovering high-purity carbon dioxide and high-purity carbon monoxide from iron and steel by-product gas are provided.

[0007]

[0008] A system for recovering carbon dioxide and carbon monoxide from a steelmaking by-product gas according to one embodiment of the present invention may include a pretreatment unit for removing impurities in the steelmaking by-product gas to produce a purified by-product gas; a carbon dioxide recovery unit for selectively separating carbon dioxide in the purified by-product gas to produce a carbon dioxide-free purified by-product gas and recovering the separated carbon dioxide; and a carbon monoxide recovery unit for recovering carbon monoxide in the carbon dioxide-free purified by-product gas. The pretreatment unit includes a separation tower, a dust collector, an adsorption tower, and a catalyst tower, and the catalyst tower can remove oxygen in the steelmaking by-product gas by catalytic reaction.

[0009] The catalyst tower can be operated at a temperature ranging from 60°C to 400°C, and the catalyst tower can be filled with a platinum group metal-containing catalyst therein.

[0010] The above platinum group metal-containing catalyst may include at least one selected from palladium (Pd), platinum (Pt), iridium (Ir), ruthenium (Ru), copper (Cu), iron (Fe), nickel (Ni), cobalt (Co), molybdenum (Mo), vanadium (V), or silver (Ag).

[0011] A U-shaped seal may be located in the pipe supplying the by-product gas of the steelmaking process to the above-mentioned pretreatment unit.

[0012] A carbon dioxide recovery unit that selectively separates carbon dioxide from the purified by-product gas to produce a carbon dioxide-free purified by-product gas and recovers the separated carbon dioxide may include a carbon dioxide separator and a carbon dioxide degasser.

[0013] The above carbon dioxide separator may include an absorbent that selectively absorbs carbon dioxide in the purified by-product gas and a separation membrane that passes the carbon dioxide-free purified gas.

[0014] The carbon monoxide recovery unit for recovering carbon monoxide in the above carbon dioxide-free purified by-product gas may include a two-stage carbon monoxide adsorber connected in series.

[0015] A method for recovering carbon dioxide and carbon monoxide from a by-product gas of a steel mill according to another embodiment of the present invention may include a pretreatment step of removing impurities in the by-product gas of the steel mill to produce a purified by-product gas; a carbon dioxide separation and recovery step of selectively separating carbon dioxide in the purified by-product gas to produce a carbon dioxide-free purified by-product gas and recovering the separated carbon dioxide; and a carbon monoxide recovery step of recovering carbon monoxide in the carbon dioxide-free purified by-product gas.

[0016] The pretreatment step of producing purified by-product gas by removing impurities in the above by-product gas of the steelmaking process can remove oxygen in the by-product gas by catalytic reaction.

[0017] In the above oxygen removal step, the space velocity of the by-product gas of the steelmaking process is hundreds of h -1 Tens of thousands of h -1 It could be a range.

[0018] The above oxygen removal step can be performed at a temperature ranging from 60°C to 400°C.

[0019] The above second pretreatment step can be performed by contacting the by-product gas from which the tar, moisture, oil, hydrogen sulfide, and dust have been removed with a platinum group metal catalyst.

[0020] In addition, the second pretreatment step may contact the by-product gas from which the tar, moisture, oil, hydrogen sulfide, and dust have been removed with a platinum group metal catalyst including at least one selected from palladium (Pd), platinum (Pt), iridium (Ir), ruthenium (Ru), copper (Cu), iron (Fe), nickel (Ni), cobalt (Co), molybdenum (Mo), vanadium (V), and silver (Ag).

[0021] The carbon dioxide separation and recovery step, which selectively separates carbon dioxide in the above-mentioned purified by-product gas to produce a carbon dioxide-free purified by-product gas and recovers the separated carbon dioxide, can produce a carbon dioxide-free purified gas by contacting the purified by-product gas with an absorption liquid to absorb carbon dioxide in the purified by-product gas.

[0022] In the step of producing a carbon dioxide-free purified gas by contacting the purified by-product gas with the absorption liquid and allowing the absorption liquid to absorb carbon dioxide in the purified by-product gas, the absorption liquid can be continuously supplied.

[0023] The gas-liquid ratio (g / l) of the purified by-product gas to the continuously supplied absorbent may be in the range of 3 to 7.

[0024] The carbon monoxide recovery step for recovering carbon monoxide in the above carbon dioxide-free purified by-product gas may include a first carbon monoxide recovery step and a second carbon monoxide recovery step.

[0025]

[0026] According to one embodiment of the present invention, a carbon dioxide and carbon monoxide recovery system can be used to efficiently recover high-purity carbon dioxide and carbon monoxide from by-product gas from a steelmaking process.

[0027] According to one embodiment of the present invention, a method for recovering carbon dioxide and carbon monoxide from by-product gas of a steel mill can efficiently recover high-purity carbon dioxide and carbon monoxide while reducing energy consumption.

[0028] FIG. 1 is a schematic diagram of a system for recovering carbon dioxide and carbon monoxide from iron ore by-product gas according to one embodiment of the present invention.

[0029] Figure 2 shows a location where gas is sampled and analyzed in one embodiment of the present invention.

[0030] Figure 3 shows the results of an oxygen removal experiment according to Example 1.

[0031] Figure 4 shows the results of an oxygen removal experiment according to Example 2.

[0032] Figure 5 shows the results of an oxygen removal experiment according to Example 3.

[0033] Figure 6 shows the results of a carbon dioxide separation experiment according to Example 4.

[0034] Figure 7 shows the results of a carbon dioxide separation experiment according to Example 5.

[0035] Figure 8a shows the carbon monoxide purity results according to Example 6.

[0036] Figure 8b shows the carbon monoxide recovery rate results according to Example 6.

[0037]

[0038] The terms first, second, and third, etc., are used to describe, but are not limited to, various parts, components, regions, layers, and / or sections. These terms are used only to distinguish one part, component, region, layer, or section from another part, component, region, layer, or section. Accordingly, a first part, component, region, layer, or section described below may be referred to as a second part, component, region, layer, or section without departing from the scope of the present invention.

[0039] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the present invention. As used herein, the singular forms "singular" and "comprising" include plural forms as well, unless the context clearly dictates otherwise. The word "comprising" as used herein specifies a particular feature, region, integer, step, operation, element, and / or component, but does not exclude the presence or addition of other features, regions, integers, steps, operations, elements, and / or components.

[0040] When a part is referred to as being "on" or "over" another part, it can be directly on or over the other part, or there may be other parts intervening. Conversely, when a part is referred to as being "directly on" another part, there are no other parts intervening.

[0041] Although not defined otherwise, all terms, including technical and scientific terms, used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention pertains. Terms defined in commonly used dictionaries are further interpreted to have meanings consistent with the relevant technical literature and the present disclosure, and are not to be construed as ideal or overly formal unless otherwise defined.

[0042] Also, unless otherwise stated, % means volume %, and 1 ppm is 0.0001 volume %.

[0043] In this specification, the term "combination(s) thereof" described in the expression in the Makushi format means one or more mixtures or combinations selected from the group consisting of the components described in the expression in the Makushi format, and means including any one or more selected from the group consisting of said components.

[0044] Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement them. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein.

[0045]

[0046] FIG. 1 is a schematic diagram of a system for recovering carbon dioxide and carbon monoxide from iron ore by-product gas according to one embodiment of the present invention.

[0047] Referring to FIG. 1 below, a recovery system and method for recovering carbon dioxide and carbon monoxide from a by-product gas of a steelmaking process according to one embodiment of the present invention will be described.

[0048] A system for recovering carbon dioxide and carbon monoxide from a steelmaking by-product gas according to one embodiment of the present invention includes a pretreatment unit (100) for removing impurities in the steelmaking by-product gas to produce purified by-product gas; a carbon dioxide recovery unit (200) for selectively separating carbon dioxide in the purified by-product gas to produce carbon dioxide-free purified by-product gas and recovering the separated carbon dioxide; and a carbon monoxide recovery unit (300) for recovering carbon monoxide in the carbon dioxide-free purified by-product gas.

[0049] The pretreatment unit (100) that removes impurities in the above-mentioned by-product gas and produces purified by-product gas may include one or more of a separation tower (110), a dust collector (120), an adsorption tower (130), and a catalyst tower (140), and specifically may include all of them.

[0050] The above separation tower (110) can remove moisture, oil, and tar in liquid form contained in the supplied iron and steel by-product gas. Meanwhile, the separation tower (110) can be used in various shapes and configurations as long as it can effectively remove the above components, and specifically, it can be in the form of a shell-tube type heat exchanger. The present invention is not particularly limited to the configuration and shape of the separation tower (110).

[0051] The by-product gas discharged from the separation tower (110) is supplied to the rear dust collector (120) through the blower (160).

[0052] The above dust collector (120) is a device for removing dust in the by-product gas of the steelmaking process, and the above adsorption tower (130) is a device for removing hydrogen sulfide in the by-product gas of the steelmaking process. By removing dust in the by-product gas of the steelmaking process in the dust collector (120), it is advantageous for the smooth operation of the entire system by preventing clogging of devices and pipes in the subsequent process. The dust collector (120) can be selected and used as one or more of a bag filter, a cartridge-type filter, or an electric dust collector, and there are no particular limitations on its form and configuration.

[0053] The by-product gas discharged from the dust collector (120) can be compressed by a compressor (170) and then supplied to the adsorption tower (130). If the temperature of the by-product gas compressed by the compressor (170) rises, the by-product gas can be cooled by a cooler (181) and then supplied to the adsorption tower (130). This is advantageous in improving the efficiency of removing impurities in the by-product gas in the adsorption tower (130).

[0054] By removing hydrogen sulfide in the by-product gas of the steelmaking process in the adsorption tower (130), problems such as catalyst poisoning and absorbent poisoning can be prevented in the subsequent process. The adsorption tower (130) may have an adsorbent placed therein. The adsorbent may be removed by a wet method in which the adsorbent is absorbed into a solvent with high solubility, such as an amine, or by a dry method in which the adsorbent is removed by adsorption. However, a dry method with excellent hydrogen sulfide removal effect is preferably used, and the adsorbent used in this case may include activated carbon, zeolite, molecular sieve, silica, and carbon molecular sieve.

[0055] The by-product gas discharged from the adsorption tower (130) can be supplied to the subsequent catalyst tower (140) to remove oxygen in the by-product gas.

[0056] The catalyst tower (140) may have a platinum group metal catalyst for oxygen removal arranged therein, and the platinum group metal-containing catalyst may include at least one selected from palladium (Pd), platinum (Pt), iridium (Ir), ruthenium (Ru), copper (Cu), iron (Fe), nickel (Ni), cobalt (Co), molybdenum (Mo), vanadium (V), and silver (Ag). Specifically, oxygen in the by-product gas of the steelmaking process may be removed through a catalytic reaction in the catalyst inside the catalyst tower (140). In the present invention, the catalyst may have a honeycomb shape, a spherical shape, or a combination thereof, and its shape is not particularly limited as long as it can effectively remove oxygen in the by-product gas of the steelmaking process.

[0057] The space velocity (SV) of the by-product gas in the catalyst tower (140) is hundreds of h -1 Tens of thousands of h -1 It can be in the range, specifically 500h -1 20000h -1 It can be in the range, more specifically 1000h -1 10000h -1 It can be within the range. When the space velocity of the by-product gas is within the above range, there is an advantage in that oxygen within the by-product gas can be effectively removed.

[0058] The by-product gas supplied to the catalyst tower (140) may be heated by a heater (182) and then introduced into the catalyst tower (140). In addition, the catalyst tower (140) may additionally include a temperature controller (not shown) for maintaining the temperature within a predetermined temperature range. The internal temperature of the catalyst tower (140) may be controlled to be 50°C or higher, specifically, may be controlled within a range of 50°C to 500°C, and more specifically, may be controlled within a range of 60°C to 450°C, 60°C to 400°C, 60°C to 300°C, 150°C to 300°C, and 200°C to 300°C. By controlling the temperature inside the catalyst tower (140) within the above range, 90% by volume or more of oxygen in the by-product gas can be removed, specifically 99.9% by volume or more can be removed, and more specifically 99.9% by volume or more can be removed.

[0059] The purified by-product gas from which oxygen has been removed in the catalyst tower (140) is cooled in the cooler (182) and then supplied to the carbon dioxide recovery unit (200) at the rear end. By cooling the high-temperature purified by-product gas discharged after reaction under heated conditions inside the catalyst tower (140) to room temperature or a temperature lower than room temperature in the cooler (182), there is an advantage in that the separation and recovery rate of carbon dioxide in the carbon dioxide recovery unit at the rear end can be improved.

[0060] The cooled purified by-product gas that has passed through the above cooler (182) is supplied to the carbon dioxide separator (210).

[0061] The carbon dioxide separator (210) may include an absorbent liquid and a separation membrane, and may include a housing containing the absorbent liquid and the separation membrane therein.

[0062] Specifically, it may include a separator mounted within the housing, and an absorbent liquid filled in the space between the outer side of the separator and the inner side of the housing.

[0063] The above separation membrane may be a hollow fiber separation membrane, and the cooled purified by-product gas that has passed through the cooler (182) may be supplied to the interior of the hollow fiber separation membrane and then diffuse into the pores of the hollow fiber separation membrane to come into contact with an absorbent located on the exterior of the hollow fiber separation membrane. When it comes into contact with the absorbent liquid, the carbon dioxide in the purified by-product gas is absorbed into the absorbent liquid. The carbon dioxide in the purified by-product gas is absorbed into the absorbent liquid, and the remaining carbon dioxide-free purified by-product gas is discharged to the outside.

[0064] At this time, the absorbent liquid is continuously supplied into the housing, and the absorbent liquid that has absorbed carbon dioxide is continuously discharged and supplied to the subsequent carbon dioxide deaerator (220).

[0065] The supply amount of the above absorption liquid can be adjusted according to the amount of purified by-product gas flowing in. The gas-liquid ratio (g / l) of the purified by-product gas to the above absorption liquid can be in the range of 2 to 15, specifically in the range of 3 to 10, and more specifically in the range of 3 to 7. Here, the volume unit of the purified by-product gas and the absorption liquid is liter (L). Meanwhile, the carbon dioxide absorption amount of the absorption liquid can be increased by adjusting the pressure of the absorption liquid within the carbon dioxide absorber (210).

[0066] The absorption liquid that has absorbed the carbon dioxide can be introduced into the absorption liquid storage tank (230) and then introduced into the carbon dioxide deaerator (220) by the liquid supply pump (260).

[0067] At this time, the pressure and temperature within the carbon dioxide degasser (220) may be atmospheric pressure or vacuum and room temperature, but are not limited thereto as long as the pressure and temperature are such that carbon dioxide in the absorbent can be degassed. Specifically, the carbon dioxide dissolved in the absorbent liquid can be degassed using a vacuum pump, and the regenerated (degassed) absorbent liquid can be stored in the absorbent liquid storage tank (240) and then re-supplied to the carbon dioxide separator (210) through the liquid supply pump (260).

[0068] The carbon dioxide-free purified by-product gas discharged from the carbon dioxide separator (210) is supplied to the carbon monoxide recovery unit (300) at the rear after removing moisture or the above-mentioned absorbent in the moisture remover (250).

[0069] The carbon monoxide recovery unit (300) may include two or more carbon monoxide adsorbers arranged in series. Although FIG. 1 illustrates a first carbon monoxide adsorber (310) and a second carbon monoxide adsorber (320) arranged in series, one or more carbon monoxide adsorbers may be additionally arranged in series after the second carbon monoxide adsorber (320).

[0070] In an embodiment of the present invention, a carbon monoxide adsorber can adsorb carbon monoxide in an incoming carbon dioxide-free purified by-product gas by filling an adsorbent therein.

[0071] At this time, the adsorbent and adsorption tower used for carbon monoxide separation may be those known to those skilled in the art. Specifically, the adsorbent may be an adsorbent that uses at least one selected from the group consisting of MOF (metal-organic framework), zeolite, activated carbon, mesoporous carbon, alumina, silica, and silica gel as a support and supports a metal-containing material. The metal-containing material may be a copper salt. More specifically, the adsorbent may be an adsorbent that supports crystalline CuCl on Theta-Al2O3.

[0072] Additionally, the carbon monoxide adsorption process may include VSA (Vacuum Swing Adsorption), PSA (Pressure Swing Adsorption), VPSA (Vacuum Pressure Swing Adsorption), TSA (Thermal Swing Adsorption), etc.

[0073] The first carbon monoxide adsorber (310) may include two or more carbon monoxide adsorption towers (311) positioned in parallel, and the second carbon monoxide adsorber (320) may include two or more carbon monoxide adsorption towers (321) positioned in parallel.

[0074] The carbon dioxide-free purified by-product gas introduced into the carbon monoxide adsorption tower (311) passes through the adsorbent layer filled in the adsorption tower (311), carbon monoxide is adsorbed on the adsorbent, and the remaining residual gas is discharged to the outside of the carbon monoxide adsorption tower (311). At this time, the carbon dioxide-free purified by-product gas can be sucked into the carbon monoxide adsorption tower (311) by the pressure reduction resulting from the operation of the vacuum pump (350) located at the rear end of the carbon monoxide adsorption tower (311).

[0075] The carbon monoxide adsorption tower (311) that adsorbs the carbon monoxide regenerates the adsorbent by removing the adsorbed carbon monoxide through a regeneration process. The adsorbent regeneration method can utilize a method known to those skilled in the art, and specifically, regeneration can be achieved by pressure reduction resulting from the operation of a vacuum pump (360).

[0076] The gas degassed in the above regeneration process can be supplied to the second carbon monoxide adsorber (320) at the rear end. Specifically, it is compressed by the compressor (370), cooled in the heat exchanger (380), and then stored in the buffer tank (330). A portion of it is supplied to the second carbon monoxide adsorber (320) at the rear end, and a portion is recycled to the first carbon monoxide adsorber (310) to control the carbon monoxide concentration to a desired level.

[0077] The second carbon monoxide adsorber (320) is configured in the same manner as the first carbon monoxide adsorber (310) and can be operated in the same manner to control the carbon monoxide concentration.

[0078] The gas discharged from the carbon monoxide adsorber can be stored in a buffer tank (400) and used to remove impurities such as dust attached to the dust collector (120) and regenerate the dust collector (120).

[0079]

[0080] In one embodiment of the present invention, the concentration of carbon monoxide is about 50% by volume in the first carbon monoxide adsorber (310) and supplied to the second carbon monoxide adsorber (320) at the subsequent stage, and the second carbon monoxide adsorber (320) can ultimately produce carbon monoxide at a concentration of 90% by volume or more.

[0081] Meanwhile, a water seal valve (150) is located at the supply terminal of the by-product gas to the separation tower (110). The water seal valve (150) is configured with the purpose of blocking the by-product gas in an emergency situation. The by-product gas contains dust and various impurities, and since it is impossible to completely block the gas through valves, there is an advantage in that it can be blocked using water pressure. The water seal valve (150) may be specifically a U-shaped pipe structure. The water seal valve (150) serves to transport gas through a U-shaped internal line in normal situations, and in an emergency situation or when the gas flow must be blocked, the gas flow can be blocked by charging water inside the U-shaped pipe. Since the pressure of the by-product gas fluid is not high, the gas flow can be blocked with a pressure difference equivalent to the height difference of the water.

[0082]

[0083] <Example 1: Oxygen Removal Experiment 1>

[0084] An oxygen removal experiment was conducted according to the internal temperature of the catalyst tower (140).

[0085] The incoming mixed gas contains 20% CO, 3% H2, 0.5% O2 and residual gas N2, and the GHSV is 8,000h. -1 . A 1 wt.% Pd / Siralox spherical catalyst was used, and the composition and content of the exhaust gas at the rear end were measured using a gas analyzer.

[0086] Figure 3 shows the results of an oxygen removal experiment according to Example 1.

[0087] Figure 3(a) shows a graph of the catalyst tower temperature settings and actual temperature by time zone, and Figure 3(b) shows the results of a composition analysis of the gas after the reaction. In addition, Figure 3(c) is a graph of the temperatures at the top and bottom of the catalyst layer, and Figure 3(d) is a graph of the CO concentration in the emitted gas.

[0088] Referring to Figure 3, when the temperature of the catalyst tower (140) is 150°C or lower, there is no oxygen consumption and the concentrations of CO2 and H2O do not increase, confirming that oxygen does not react. On the other hand, the concentration of oxygen decreases from 200°C, and when the temperature is 300°C or higher, all oxygen reacts and is completely consumed.

[0089] <Example 2: Oxygen Removal Experiment 2>

[0090] An oxygen removal experiment was performed in the same manner as Example 1, except that the incoming mixed gas contained 30% CO, 3% H2, 0.5% O2, and residual gas N2.

[0091] Figure 4 shows the results of an oxygen removal experiment according to Example 2.

[0092] Figure 4(a) shows a graph of the catalyst tower temperature settings and actual temperature by time zone, and Figure 4(b) shows the results of a composition analysis of the gas after the reaction. In addition, Figure 4(c) is a graph of the temperatures at the top and bottom of the catalyst layer, and Figure 4(d) is a graph of the CO concentration in the emitted gas.

[0093] Referring to Fig. 4, when the temperature of the catalyst tower (140) is 200°C or lower, there is no oxygen consumption and the concentrations of CO2 and H2O do not increase, confirming that oxygen does not react. On the other hand, the concentration of oxygen decreases from 200°C, and when the temperature is 400°C or higher, all oxygen reacts and is completely consumed.

[0094]

[0095] <Example 3: Oxygen Removal Experiment 3>

[0096] Oxygen removal experiments were performed according to the Pd content in the catalyst.

[0097] The catalysts used were a 1 wt.% Pd / Siralox spherical catalyst and a 0.5 wt.% Pd / Siralox spherical catalyst, respectively, and the catalysts were treated by passing them through air at 400°C for 3 hours and then used in an oxygen removal experiment.

[0098] The incoming mixed gas is BFG gas, and contains 24% CO, 23% H2, 0.4% O2, and residual gas N2 by volume, and the GHSV is 10,000h. -1 The composition and content of the exhaust gas at the rear end were measured using a gas analyzer.

[0099] Figure 5 shows the results of an oxygen removal experiment according to Example 3.

[0100] Referring to Fig. 5, in the case of a 1 wt.% Pd / Siralox spherical catalyst, the oxygen removal rate was found to be 80% or higher at 60°C or higher, and 100% at 175°C. In the case of a 0.5 wt.% Pd / Siralox spherical catalyst, the oxygen removal rate was found to be 80% or higher at 150°C or higher, and 100% at 225°C.

[0101]

[0102] <Example 4: Carbon Dioxide Separation Experiment>

[0103] A carbon dioxide absorption experiment was conducted according to the mixed gas flow rate flowing into the carbon dioxide separator (210).

[0104] The mixed gas flowing into the carbon dioxide separator contained 57.8% N2, 20.2% CO, and 21.9% CO2, and distilled water was used as the absorbent, which was supplied at 3 L / min. At this time, the gas pressure was controlled to 6 barg, the absorbent pressure to 7 barg, and the experiment was performed using the Liqui-cel module 4X28 as the separation membrane module. The gas flow rate and the carbon dioxide concentration in the gas discharged from the carbon dioxide separator (210) were measured to calculate the carbon dioxide removal rate, which is shown in Fig. 6.

[0105] Referring to Figure 6, the carbon dioxide removal rate tended to increase as the gas inflow rate decreased. When the gas inflow rate was 20 L / min, the carbon dioxide removal rate was 87.9%, and when the gas inflow rate was 10 L / min, the carbon dioxide removal rate was 98.9%.

[0106]

[0107] <Example 5: Carbon Dioxide Separation and Recovery Experiment>

[0108] A carbon dioxide absorption experiment was conducted according to the flow rate of the absorption liquid flowing into the carbon dioxide separator (210).

[0109] The mixed gas flowing into the carbon dioxide separator contained 58% N2, 20% CO, and 22% CO2, and the mixed gas flow rate was supplied at 20 L / min. A carbon dioxide absorption experiment was performed in the same manner as in Example 3, except that the supply flow rate of the absorption liquid was changed. The gas flow rate and the carbon dioxide concentration in the gas discharged from the carbon dioxide separator (210) were measured to calculate the carbon dioxide removal rate and recovery rate, and these are shown in Fig. 7.

[0110] Referring to Figure 7, as the absorption liquid flow rate increases, the CO2 removal rate shows an increasing trend, but the CO2 recovery rate and the CO2 concentration in the emitted gas show an increasing trend and then slightly decreasing.

[0111] In the present invention, the removal rate and recovery rate of carbon dioxide were calculated using the following methods.

[0112] Carbon dioxide removal rate (%) = {(carbon dioxide intake inlet concentration x intake inlet flow rate) - (carbon dioxide intake outlet concentration x intake outlet flow rate)} / (carbon dioxide inlet concentration x inlet flow rate) x 100(%)

[0113] Carbon dioxide recovery rate (%) = {(carbon dioxide stripping concentration x stripping flow rate) + (carbon dioxide intake outlet concentration x intake outlet flow rate)} / (carbon dioxide intake inlet concentration x intake inlet flow rate) x 100(%)

[0114]

[0115] <Example 6: Carbon Monoxide Separation and Recovery Experiment>

[0116] An experiment was conducted to separate and recover carbon monoxide in a gas in a first carbon monoxide adsorber (310) and a second carbon monoxide adsorber (320).

[0117] The mixed gas flowing into the carbon dioxide separator contained 30% CO and the remainder N2, and the adsorbent used was an adsorbent with crystalline CuCl supported on a Theta-Al2O3 support, and the mixed gas flow rate was supplied at 2 to 8 L / min. At this time, the gas pressure was 7 barg and the adsorbent temperature was controlled at 30°C. At this time, the volume concentration of carbon monoxide in the gas flowing into the second carbon monoxide adsorber (320) was controlled to be 50%.

[0118] Figure 8a shows the volume concentration of carbon monoxide in the gas discharged from the rear end of the second carbon monoxide adsorber (320), and Figure 8b shows the carbon monoxide recovery rate.

[0119] Referring to FIGS. 8a and 8b, it can be seen that as the gas flow rate introduced into the second carbon monoxide adsorber (320) increases, the carbon monoxide concentration in the produced gas tends to increase, while the carbon monoxide recovery rate tends to decrease somewhat. When the inlet gas flow rate is 8 L / min, the carbon monoxide volume concentration in the final produced gas is 93.6%, and the carbon monoxide recovery rate is approximately 77.0%.

[0120] In the present invention, the concentration of carbon monoxide is the concentration of carbon monoxide in the total gas concentration, and the recovery rate of carbon monoxide was calculated by the following method.

[0121] Carbon monoxide recovery rate (%) = (Carbon monoxide recovery concentration x recovery flow rate) / (Input carbon monoxide concentration x inflow flow rate) x 100 (%)

[0122]

[0123] <Example 7: Separation and recovery of carbon dioxide and carbon monoxide in steelmaking by-product gas>

[0124] Experiments were conducted to separate carbon dioxide through a membrane contactor using by-product gas from the steel mill and to separate and recover carbon monoxide using PSA.

[0125] Figure 2 shows a location where gas is sampled and analyzed in one embodiment of the present invention.

[0126] The gas flow rate, temperature, pressure, and components contained in the gas were analyzed by process location and summarized in Table 1 below.

[0127] At this time, the carbon dioxide absorbent was distilled water and was introduced at a rate of 5 t / h, and the carbon monoxide absorbent used was an adsorbent having a CuCl crystal structure and a theta-Al2O3 support.

[0128]

[0129]

[0130] Measurement location 123456789101112 Gas flow rate Nm 3 / h5045.845.845.845.845.845.845.845.645.6Temperature℃404040.040.0290.24040200272.7404040PressureBarg0.01960.01960.01960.01968.08.08.08.08.08.0Gas Content by compositionCO%19.521.321.321.321.321.321.321.321.321.421.4CO2%18.520.220.220.220.220.220.220.220.320.3H2%2.93.13.13.13.13.13.13.13.12.22.2N2%42.045.845.845.845.845.845.845.846.146.1O2%0.40.50.50.50.50.50.50.50.00.0H2O%16.79.19.19.19.19.19.19.110.110.1Dustmg / m 3 200.0200.0200.02.02.02.02.02.02.02.02.0Total%100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.00.0Gas composition-by-flow rateCONm 3 / h9.79.79.79.79.79.79.79.79.79.7CO2Nm 3 / h9.29.29.29.29.29.29.29.29.29.29.28.3H2Nm 3 / h1.41.41.41.41.41.41.41.41.01.0N2Nm 3 / h21.021.021.021.021.021.021.021.021.021.021.00.4O2Nm 3 / h0.20.20.20.20.20.20.20.20.20.00.0H2ONm 3 / h8.44.24.24.24.24.24.24.24.24.64.65(t / h)5(t / h)TotalNm 3 / h50.045.845.845.845.845.845.845.845.845.645.6Measuring position131415161718192021222317+21Gas flow rateNm 3 / h8.836.832.714.618.114.614.68.85.88.88.823.9Temperature℃3030303030.0535.8303030541.93030.0PressureBarg-0.58.08.0-0.57.08.08.0-0.57.08.08.07.0Gas Composition content CO% 0.026.529.860.05.460.060.090.015.090.090.07.7 CO2% 95.02.52.81.63.81.61.60.43.40.40.43.7 H2% 0.02.73.11.74.11.71.70.43.70.40.44.0 N 2%5.055.862.935.884.835.835.89.076.29.09.082.7O2%0.00.00.00.00.00.0 0.00.00.00.00.00.0H2O%0.012.51.40.81.90.80.80.21.70.20.21.9Dustmg / m 3 0.00.00.00.00.00.00.00.00.0100.00.00.00.0Total%100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0Gas composition-specific flow rateCONm 3 / h0.09.79.78.81.08.88.87.90.97.97.91.9CO2Nm 3 / h8.30.90.90.20.70.20.20.00.20.00.00.9H2Nm 3 / h0.01.01.00.30.70.30.30.00.20.00.01.0N2Nm 3 / h0.420.620.65.215.35.25.20.84.50.80.819.8O2Nm 3 / h0.00.00.00.00.00.00.00.00.00.00.00.00.00.0H2ONm 3 / h0.04.60.50.10.30.10.10.00.10.00.00.4TotalNm 3 / h8.836.832.714.618.114.614.68.85.88.88.823.9

[0131]

[0132] While preferred embodiments of the present invention have been described above, the present invention is not limited thereto. Various modifications and variations within the scope of the claims, the detailed description, and the accompanying drawings are possible, and such modifications also fall within the scope of the present invention. Therefore, the substantial scope of the present invention is defined by the appended claims and their equivalents.

[0133] (Explanation of symbols)

[0134] 100: By-product gas pretreatment unit 110: Separator

[0135] 120: Dust collector 130: Adsorption tower

[0136] 140: Catalyst tower 150: Subongbyeon

[0137] 160: Blower 170: Compressor

[0138] 181: Cooler 182: Heater

[0139] 183: Cooler 200: CO2 recovery unit

[0140] 210: CO2 separator 220: CO2 deaerator

[0141] 230, 240: Absorbent storage tank 250: Moisture remover

[0142] 260: Liquid supply pump 300: CO recovery unit

[0143] 310: First CO adsorber 311, 321: Carbon monoxide adsorption tower

[0144] 320: Second CO adsorber 330, 340: Buffer tank

[0145] 350, 360: Vacuum pump 370: Compressor

[0146] 380: Heat exchanger 400: Buffer tank

Claims

1. Pretreatment unit that removes impurities in the by-product gas of the steel mill to produce purified by-product gas; A carbon dioxide recovery unit that selectively separates carbon dioxide from the purified by-product gas to produce carbon dioxide-free purified by-product gas and recovers the separated carbon dioxide; and It includes a carbon monoxide recovery unit for recovering carbon monoxide in the carbon dioxide-free purified by-product gas; The above pretreatment unit includes a separation tower, a dust collector, an adsorption tower, and a catalyst tower. The above catalyst tower removes oxygen in the by-product gas of the steelmaking process through a catalytic reaction. Recovery system for carbon dioxide and carbon monoxide from by-product gas of steel mills.

2. In paragraph 1, The above catalyst tower is operated at a temperature ranging from 60°C to 400°C. Recovery system for carbon dioxide and carbon monoxide from by-product gas of steel mills.

3. In paragraph 1, The above catalyst tower is filled with a platinum group metal-containing catalyst inside. Recovery system for carbon dioxide and carbon monoxide from by-product gas of steel mills.

4. In paragraph 3, The platinum group metal-containing catalyst includes at least one selected from palladium (Pd), platinum (Pt), iridium (Ir), ruthenium (Ru), copper (Cu), iron (Fe), nickel (Ni), cobalt (Co), molybdenum (Mo), vanadium (V), or silver (Ag). Recovery system for carbon dioxide and carbon monoxide from by-product gas of steel mills.

5. In paragraph 1, A U-shaped water seal is located in the pipe that supplies the by-product gas of the steelmaking process to the above-mentioned pretreatment unit. Recovery system for carbon dioxide and carbon monoxide from by-product gas of steel mills.

6. In paragraph 1, A carbon dioxide recovery unit that selectively separates carbon dioxide from the above-mentioned purified by-product gas to produce carbon dioxide-free purified by-product gas and recovers the separated carbon dioxide; Includes a carbon dioxide separator and a carbon dioxide degasser, The carbon dioxide separator includes an absorbent that selectively absorbs carbon dioxide in the purified by-product gas and a separation membrane that passes the carbon dioxide-free purified gas. Recovery system for carbon dioxide and carbon monoxide from by-product gas of steel mills.

7. In paragraph 1, The carbon monoxide recovery unit that recovers carbon monoxide in the above carbon dioxide-free purified by-product gas is Comprising a two-stage carbon monoxide adsorber connected in series, Recovery system for carbon dioxide and carbon monoxide from by-product gas of steel mills.

8. Pretreatment step to produce purified by-product gas by removing impurities in the by-product gas of the steel mill; A carbon dioxide separation and recovery step for selectively separating carbon dioxide in the above-mentioned purified by-product gas to produce carbon dioxide-free purified by-product gas and recovering the separated carbon dioxide; and A carbon monoxide recovery step for recovering carbon monoxide in the carbon dioxide-free purified by-product gas; The pretreatment step of producing purified by-product gas by removing impurities in the above by-product gas of the steel mill is to remove oxygen in the by-product gas by catalytic reaction. Method for recovering carbon dioxide and carbon monoxide from by-product gas of steelmaking.

9. In paragraph 8, In the above oxygen removal step, the space velocity of the by-product gas of the steelmaking process is hundreds of h -1 Tens of thousands of h -1 It is a range, Method for recovering carbon dioxide and carbon monoxide from by-product gas of steelmaking.

10. In paragraph 8, The above oxygen removal step is performed at a temperature ranging from 60°C to 400°C. Method for recovering carbon dioxide and carbon monoxide from by-product gas of steelmaking.

11. In paragraph 8, The above second preprocessing step is, The by-product gas from which the above tar, moisture, oil, hydrogen sulfide and dust have been removed is brought into contact with a platinum group metal catalyst. Method for recovering carbon dioxide and carbon monoxide from by-product gas of steelmaking.

12. In paragraph 11, The above second preprocessing step is, The by-product gas from which the tar, moisture, oil, hydrogen sulfide and dust have been removed is brought into contact with a platinum group metal catalyst including at least one selected from palladium (Pd), platinum (Pt), iridium (Ir), ruthenium (Ru), copper (Cu), iron (Fe), nickel (Ni), cobalt (Co), molybdenum (Mo), vanadium (V) and silver (Ag). Method for recovering carbon dioxide and carbon monoxide from by-product gas of steelmaking.

13. In paragraph 8, The carbon dioxide separation and recovery step, which selectively separates carbon dioxide from the above-mentioned purified by-product gas to produce carbon dioxide-free purified by-product gas and recovers the separated carbon dioxide, is By contacting the above purified by-product gas with the absorbent, carbon dioxide in the purified by-product gas is absorbed by the absorbent, thereby producing a carbon dioxide-free purified gas. Method for recovering carbon dioxide and carbon monoxide from by-product gas of steelmaking.

14. In paragraph 13, The step of producing carbon dioxide-free purified gas by contacting the purified by-product gas with the absorbent and absorbing the carbon dioxide in the purified by-product gas into the absorbent is as follows: The above absorbent liquid is continuously supplied, Method for recovering carbon dioxide and carbon monoxide from by-product gas of steelmaking.

15. In paragraph 14, The gas-liquid ratio (g / l) of the purified by-product gas to the continuously supplied absorbent is in the range of 3 to 7. Method for recovering carbon dioxide and carbon monoxide from by-product gas of steelmaking.

16. In paragraph 8, The carbon monoxide recovery step for recovering carbon monoxide in the above carbon dioxide-free purified by-product gas is as follows: Comprising a first carbon monoxide recovery step and a second carbon monoxide recovery step, Method for recovering carbon dioxide and carbon monoxide from by-product gas of steelmaking.

Images