Specification
Title of Invention: Carbon monoxide manufacturing method and its application
technical field
[One]
The present disclosure relates to a method for producing carbon monoxide. More specifically, the present disclosure relates to a method of converting carbon dioxide into carbon monoxide and utilizing the same to reduce carbon dioxide emissions.
background
[2]
The reduction process in the ironmaking industry is a process in which carbon in coke and iron ore undergo a chemical reaction in a blast furnace called a blast furnace due to a high temperature to obtain liquid iron. The problem of the current steelmaking process is that a large amount of carbon dioxide (CO 2 ) is inevitably generated by using a carbon-based reducing agent such as coal for this reduction process. However, as the global pressure on carbon dioxide emission regulation increases, the steel industry is increasingly interested in eco-friendly processes in terms of environment, energy, and cost competitiveness. In particular, after the Kyoto Protocol, efforts to reduce CO 2 generation and save energy are accelerating. In the case of the steel industry, the application of a carbon tax is being promoted, and interest in methods for lowering the reducing agent cost used in blast furnaces and reduction of carbon dioxide emissions is increasing recently.
[3]
In order to reduce the amount of carbon dioxide generated in the process of manufacturing molten iron, it is important to efficiently use the exhaust gas generated during the manufacturing of molten iron. The main components of the exhaust gas generated during the production of molten iron include CO, H 2 , CO 2 , H 2 O, N 2 and the like, and CO and H 2 in the exhaust gas can be used as a reducing agent or a heat source that generates heat.
[4]
Therefore, in an effort to reduce the reducing agent cost and carbon dioxide used in the blast furnace, a technology that selects only carbon monoxide (CO) from the blast furnace flue gas and reinjects it into the blast furnace, replaces carbon (coal) and uses hydrogen as a medium to reduce through hydrogen reduction Technologies to lower swallows and fundamentally block carbon dioxide emissions are being studied. However, the technology of selectively separating and recovering carbon monoxide and re-blowing into the blast furnace has a problem in that the separation recovery recovery rate of CO and N 2 in the flue gas is low, and the hydrogen reduction technology using hydrogen as a medium is economical and uses a reducing agent There is a problem in that the change in operation cannot be predicted. In addition, in order to re-inject the separated CO gas and produced hydrogen gas into the blast furnace, there is a problem that the temperature must be raised to 1200° C. or higher, which is the blast furnace blowing temperature, in consideration of the heat balance inside the blast furnace, so development is still required.
DETAILED DESCRIPTION OF THE INVENTION
technical challenge
[5]
In order to solve this problem, the present disclosure selectively separates and collects carbon dioxide from the blast furnace flue gas, then recycles by-products generated in the steel mill to reduce carbon dioxide to carbon monoxide, and to propose a method of reintroducing the produced carbon monoxide into the blast furnace. do.
means of solving the problem
[6]
A method for manufacturing molten iron according to an embodiment of the present invention includes the steps of collecting carbon dioxide in an exhaust gas generated in a blast furnace; reforming the carbon dioxide into carbon monoxide; and re-blowing the carbon monoxide into the blast furnace. Including, and re-blowing the carbon monoxide into the blast furnace; in [Equation 1] CO gas re-injection amount (Nm 3 /min) may be 500 to 1270 or less.
[7]
[Equation 1] CO gas re-injection amount (Nm 3 /min) = CO2 gas content in flue gas (Nm 3 /ton) X Molten iron output (ton/day) X CO2 gas ratio injected into the tannery (50%)X CO gas conversion rate (%)X(1 day/1440 min)
[8]
In the molten iron manufacturing method, the CO gas circulation rate of [Equation 2] may be 15 to 40%.
[9]
[Equation 2] CO gas circulation rate (%) = CO gas re-injection amount (Nm 3 /min)/[CO gas content in flue gas (Nm 3 /ton)X molten iron production (ton/day)]X(1440 min/1 day)X100[%]
[10]
The CO gas conversion rate of [Formula 1] or [Formula 2] may be 35% or more to less than 85%.
[11]
In the step of re-blowing the carbon monoxide into the blast furnace, the temperature of the carbon monoxide may be 800 ℃ or more.
[12]
In the step of re-blowing the carbon monoxide into the blast furnace, the pulverized coal injection amount (kr/ton-pig) according to the CO conversion rate of [Equation 3] may satisfy 100 to 170 kg/ton-pig.
[13]
[Equation 3] Pulverized coal injection according to CO conversion rate (kg/ton-pig) = -0.007*[CO conversion rate (%)] 2 -0.00005*[CO conversion rate (%)]+170.3
[14]
The carbon dioxide reforming apparatus of the embodiment of the present disclosure is filled with a mixture of carbon-containing by-product and iron-containing by-product, and the mixing ratio of the carbon-containing by-product and the iron-containing by-product is 10 to 50 weight of the iron-containing by-product based on 100% by weight of the carbon-containing by-product %, and may be to reform carbon dioxide into carbon monoxide.
[15]
The specific surface area of ​​the carbon-containing by-product may be 50 m 2 /g or more.
[16]
The carbon component of the carbon-containing by-product may be 80 wt% or more, and the iron-containing component of the iron-containing by-product may be 50 wt% or more.
[17]
The carbon dioxide reforming apparatus according to the exemplary embodiment of the present disclosure may be an apparatus for reforming carbon dioxide in an exhaust gas generated in a blast furnace, and the carbon dioxide reforming apparatus may be installed in a molten material runway during an ironmaking process.
[18]
In the carbon dioxide reforming apparatus, one or more apparatuses may be installed throughout the melt runway area.
[19]
When there are two or more carbon dioxide reforming apparatuses, the reaction tubes may be installed in a bundle form or a mesh network form to be fixedly connected.
[20]
The melt runway may have a cover over the melt, and the carbon dioxide reforming device may exist between the melt and the cover.
[21]
The temperature between the melt and the cover in the melt runway may be 900° C. or higher.
[22]
The position of the carbon dioxide reforming device may be adjusted in consideration of the amount of melt in the melt sump.
Effects of the Invention
[23]
According to one embodiment of the present invention, carbon dioxide captured in the blast furnace may be reformed into carbon monoxide in the carbon dioxide reforming apparatus.
[24]
In addition, according to one embodiment of the present invention, when the carbon dioxide reforming apparatus is re-injected into the blast furnace by using the radiant heat of the melt from the melt runway, it is possible to maintain the energy balance in the blast furnace.
[25]
In addition, according to one embodiment of the present invention, carbon dioxide emission can be reduced because carbon dioxide in the blast furnace flue gas is captured and used.
[26]
In addition, according to one embodiment of the present invention, it is possible to reduce the reducing agent ratio by re-blowing the produced carbon monoxide into the blast furnace.
Brief description of the drawing
[27]
1 shows an overall configuration diagram of carbon monoxide production and utilization of one embodiment of the present invention.
[28]
2 is a schematic diagram showing a partial configuration in which the carbon dioxide reforming apparatus is located in the tangent according to an embodiment of the present invention.
[29]
Figure 3 shows the carbon monoxide conversion rate of the carbon-containing by-product utilizing radiant heat according to an embodiment of the present invention.
[30]
4 shows the carbon monoxide conversion rate of the carbon-containing by-product and the iron-containing by-product utilizing radiant heat according to an embodiment of the present invention.
[31]
5 is a schematic view of a CO reforming reaction tube installed in the tang.
Modes for carrying out the invention
[32]
The terms first, second, 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.
[33]
The terminology used herein is for the purpose of referring to specific embodiments only, and is not intended to limit the present invention. As used herein, the singular forms also include the plural forms unless the phrases clearly indicate the opposite. As used herein, the meaning of “comprising” specifies a particular characteristic, region, integer, step, operation, element and/or component, and the presence or absence of another characteristic, region, integer, step, operation, element and/or component; It does not exclude additions.
[34]
When a part is referred to as being “on” or “on” another part, it may be directly on or on the other part, or the other part may be involved in between. In contrast, when a part refers to being “directly above” another part, the other part is not interposed therebetween.
[35]
In addition, unless otherwise specified, % means weight %, and 1 ppm is 0.0001 weight %.
[36]
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 art to which the present invention belongs. Commonly used terms defined in the dictionary are additionally interpreted as having a meaning consistent with the related technical literature and the presently disclosed content, and unless defined, they are not interpreted in an ideal or very formal meaning.
[37]
Hereinafter, embodiments of the present invention will be described in detail so that those of ordinary skill in the art to which the present invention pertains can easily implement them. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein.
[38]
1 is an overall configuration diagram of carbon monoxide production and utilization in the production of molten iron according to an embodiment of the present invention. Currently, the process of manufacturing molten iron in an integrated steel mill mainly relies on the blast furnace method, and most of them use carbon monoxide generated from coal as a reducing agent for iron ore. For example, to produce 1 ton of steel products, about 2.18 tons of carbon dioxide is generated, 80% of which is due to the use of coal in the molten iron manufacturing process. On the other hand, the price of coal for coking suitable for the blast furnace process has increased significantly due to the recent surge in the price of fuel materials in the steel industry, which is deteriorating the price competitiveness of the molten iron manufacturing process. In order to solve this problem, a method of selectively separating and recovering carbon dioxide in the blast furnace flue gas, reforming it into carbon monoxide, and re-blowing it back into the blast furnace is proposed and shown in FIG. 1 . The content of carbon dioxide in the flue gas component in the blast furnace is about 20-25%, and in the case of a blast furnace with an internal volume of 5000 Nm 3 or more, more than 16,000 Nm 3 of carbon dioxide is emitted per minute . Carbon monoxide is produced by the method presented. At this time, the temperature of the produced carbon monoxide is about 800°C, and the use of coke and PCI coal used as reducing agents can be reduced by blowing the produced high-temperature carbon monoxide into the blast furnace tuyere.
[39]
Hereinafter, a method for manufacturing molten iron in which carbon dioxide is reformed into carbon monoxide and re-blowed will be described in more detail.
[40]
A method for producing molten iron according to an embodiment of the present invention includes the steps of: collecting carbon dioxide in an exhaust gas generated in a blast furnace; reforming the carbon dioxide into carbon monoxide; and re-blowing the carbon monoxide into the blast furnace. Including, and re-blowing the carbon monoxide into the blast furnace; in [Equation 1], the CO gas re-injection amount (Nm 3 /min) may be 500 or more to 1270 Nm 3 /min or less. Specifically, the value of [Equation 1] may be 500 to 970 Nm 3 /min, and more specifically, the value of [Formula 1] may be 500 to 750 Nm 3 /min. If the value of [Equation 1] is less than 500 Nm 3 /min, there may be a slight problem in the CO 2 reduction effect compared to the technology investment, and if the value of [Equation 1] exceeds 1270 Nm 3 /min, the amount of carbon monoxide is large There may be a problem in that the amount of air blown into the blast furnace (Total Input Gas) is reduced accordingly, and the oxygen load must be increased in order to preserve the reduced thermal energy.
[41]
[Equation 1] CO gas re-injection amount (Nm 3 /min) = CO2 gas content in flue gas (Nm 3 /ton) X Molten iron output (ton/day) X CO2 gas ratio injected into the tannery (50%)X CO gas conversion rate (%)X(1 day/1440 min)
[42]
In the molten iron manufacturing method, the CO gas circulation rate of [Equation 2] may be 15 to 40%. Specifically, the value of [Formula 2] may be 16 to 32%, more specifically 24 to 32%, more specifically 24 to 30%. If the value of the CO gas circulation rate in [Equation 2] is less than 15%, there may be a slight problem in the CO 2 reduction effect compared to the technology investment, and when the value of the CO gas circulation rate exceeds 40%, the amount of carbon monoxide is large As a result, the amount of air blown into the blast furnace (Total Input Gas) is reduced, and there may be a problem in that the oxygen load must be increased in order to preserve the reduced thermal energy.
[43]
[Equation 2] CO gas circulation rate (%) = CO gas re-injection amount (Nm 3 /min)/[CO gas content in flue gas (Nm 3 /ton)X molten iron production (ton/day)]X(1440 min/1 day)X100[%]
[44]
The CO gas conversion rate of [Formula 1] or [Formula 2] may be 35% or more to less than 85%.
[45]
In the step of re-blowing the carbon monoxide into the blast furnace, the carbon monoxide temperature may be 800 °C or higher, specifically 800 to 1500 °C, more specifically 900 to 1200 °C, and more specifically 1000 to 1100 °C.
[46]
In the step of re-blowing the carbon monoxide into the blast furnace, the pulverized coal injection amount (kr/ton-pig) according to the CO conversion rate of [Equation 3] may satisfy 100 to 170 kg/ton-pig. Specifically, the value of Formula 2 may be 100 (kg/ton-pig) or more, specifically 170 to 100, more specifically, 170.3 (kg/ton-pig) to 100.295 (kg/ton-pig). When the amount of pulverized coal blowing in [Equation 3] is less than 100 kg/ton-pig, there may be a problem in that the heat in the furnace is insufficient. There may be a problem in that the objective of reducing the reducing agent cost cannot be achieved.
[47]
[Equation 3] Pulverized coal injection according to CO conversion rate (kg/ton-pig) = -0.007*[CO conversion rate (%)] 2 -0.00005*[CO conversion rate (%)]+170.3
[48]
The step of collecting carbon dioxide in the exhaust gas generated in the blast furnace; is at least one method selected from the group consisting of PSA (Pressure Swing Adsorption), deep cooling method, ammonia / amine absorption method, adsorbent usage, MOF (Metal organic framework), and membrane separation method carbon dioxide can be selectively captured.
[49]
The conversion rate for reforming carbon monoxide from carbon dioxide may be 35% or more, specifically 35 to 85%. More specifically, the conversion may be 35 to 64%, more specifically 35 to 50%.
[50]
The reformed carbon monoxide may be recycled where a heat source is needed, such as in a hot water refractory, in addition to being re-introduced into the blast furnace through the blast furnace tuyere.
[51]
2 is a schematic partial configuration diagram of carbon monoxide production in a tango according to an embodiment of the present invention. In general, sinter, coke, and limestone are fed from the top of the blast furnace and slowly fall down. At this time, the coke is burned by hot air flowing into the bottom of the blast furnace, and carbon monoxide generated in this process undergoes a reduction reaction with iron ore to produce molten iron. At this time, the temperature of the resulting melt is 1,500 °C or higher. By this temperature, radiant heat is emitted to the melt runway, and the temperature of the radiant heat at this time is about 900°C to 1200°C. A carbon dioxide reforming device formed of a material having excellent conductivity is installed on the upper part of the melt, and carbon dioxide is blown in. Carbon-containing by-products and iron-containing by-products are mixed in a certain ratio among the iron-making by-products and then filled, and carbon dioxide is reformed into carbon monoxide by utilizing radiant heat from the melt. The carbon-containing by-product may supply a carbon source for reforming carbon dioxide into carbon monoxide, and the iron-containing by-product may serve as a reforming catalyst.
[52]
Hereinafter, each configuration of the carbon dioxide reforming apparatus will be described in more detail.
[53]
The carbon dioxide reforming apparatus of one embodiment of the present invention may promote the Boudouard reaction between carbon dioxide and carbon-containing byproducts to reform carbon dioxide into carbon monoxide as shown in the following reaction formula.
[54]
CO 2 + C → 2CO
[55]
In the carbon dioxide reforming apparatus of one embodiment of the present invention, a mixture of carbon-containing by-product and iron-containing by-product is filled therein, and the mixing ratio of the carbon-containing by-product and the iron-containing by-product is 10 to 50 of the iron-containing by-product based on 100 wt% of the carbon-containing by-product. It may be included in weight %.
[56]
The mixing ratio of the carbon-containing by-product and the iron-containing by-product in the mixture may be adjusted according to the iron-containing content in the iron-containing by-product. Specifically, the amount of the iron-containing by-product may be 0 to 50 wt%, specifically 10 to 40 wt%, and more specifically 20 to 40 wt%, based on 100 wt% of the carbon-containing by-product. When the iron-containing by-product is mixed in excess of 50 wt% with respect to 100 wt% of the carbon-containing by-product, the surface of the carbon-containing by-product reacting with the CO 2 gas is excessively covered, so that the interface between the CO 2 gas and the carbon-containing by-product acting as an active point is Rather, there may be a reduction problem.
[57]
The specific surface area of ​​the carbon-containing by-product may be 50 m 2 /g or more, specifically, the specific surface area may be 50 to 300 m 2 /g, more specifically 100 to 290 m 2 /g, more specifically 200 to 285 m 2 /g, more specifically 250 to 280 m 2 /g. If the specific surface area is less than 50 m 2 /g, there may be a problem that the reaction rate or conversion rate is lowered because the reaction with the gas is significantly lowered . Since it reacts with more gas, the reaction time is shortened, so there may be a problem that it is difficult to control.
[58]
The carbon component of the carbon-containing by-product may be 60 wt% or more, specifically, 80 to 90 wt%, and more specifically 82 to 87 wt%. When the carbon component of the carbon-containing by-product is less than 60% by weight, there may be a problem in that the amount of converted gas is reduced by reducing the amount of carbon compared to the amount of gas blown, and when the carbon component is more than 90% by weight, compared to the amount of gas blown Therefore, there may be a problem that there is a deactivated carbon component because there are many carbon components.
[59]
The iron-containing component of the iron-containing by-product may be 50 wt% or more, specifically 50 to 100 wt%, and more specifically 50 to 60 wt%. When the iron-containing component of the iron-containing by-product is less than 50% by weight, the active energy of the reaction is increased due to the reduction of the iron-containing component serving as a catalyst, thereby slowing the reaction rate and thus there may be a problem in that the conversion rate is lowered.
[60]
In addition, the carbon dioxide reforming apparatus according to one embodiment of the present invention may be an apparatus for reforming carbon dioxide in the flue gas generated in a blast furnace, and the carbon dioxide reforming apparatus may be installed in a molten material runway during an iron making process. The carbon dioxide reforming device may be installed in the melt runway during the iron making process to use radiant heat of the melt (see FIG. 5 ).
[61]
The carbon dioxide reforming device may be a device in which one or more devices are installed over the entire melt runway area. In addition, it may be detachable depending on the operating conditions in the tangdo. In addition, as the number of carbon dioxide reforming units is one or more, the carbon dioxide injection inlet may also be one or more.
[62]
When there are two or more carbon dioxide reforming apparatuses, the reaction tubes may be installed in a bundle form or a mesh network form to be fixedly connected.
[63]
The melt runway may have a cover on the melt, and the carbon dioxide reforming device may exist between the melt and the cover.
[64]
The temperature of the air between the melt and the cover may be 900 °C or higher, specifically 900 to 1500 °C, more specifically 900 to 1200 °C. This high-temperature heat is transferred to the carbon dioxide reforming device, and the carbon dioxide reacts with carbon-containing by-products to be reformed into carbon monoxide.
[65]
The position of the carbon dioxide reforming device may be adjusted in consideration of the amount of melt in the runway. Specifically, the location of the carbon dioxide reforming device may be determined according to the temperature and amount of the melt flowing in the tang.
[66]
Specifically, when the melt flows in the melt runway, the carbon dioxide reforming device may be installed 100 to 500 mm above the surface of the melt, specifically 200 to 400 mm above the melt surface. If it is installed too close from the top of the melt surface, there may be a problem of deformation of the installed reaction tube. There may be unsolved issues.
[67]
The material of the carbon dioxide reforming device is sufficient as long as the radiant heat of the melt in the melt runway is well transmitted, and may be at least one selected from the group consisting of tungsten, molybdenum, silicon carbide, and aluminum nitride, specifically tungsten. .
[68]
Hereinafter, the present invention will be described in more detail through examples. However, these examples are for illustrative purposes only, and the present invention is not limited thereto.
[69]
Example 1 - Comparison according to carbon monoxide conversion
[70]
In the present invention, carbon monoxide gas in the flue gas in the blast furnace was reformed into carbon monoxide and re-introduced into the blast furnace tuyere, and the heat balance was calculated using the thermal mass balance formula to investigate the blast furnace heat balance and carbon dioxide reduction effect. Table 1 shows the balance in the blast furnace and the carbon dioxide reduction effect according to the carbon monoxide re-injection into the blast furnace tuyere for each carbon monoxide gas conversion rate manufactured according to an embodiment of the present invention in molten iron.
[71]
[Table 1]
[72]
*Base refers to the existing blast furnace that does not inject reformed carbon monoxide.
[73]
*tp means ton-pig.
[74]
[Equation 3] Pulverized coal injection according to CO conversion rate (kg/ton-pig) = -0.007*[CO conversion rate (%)] 2 -0.00005*[CO conversion rate (%)]+170.3
[75]
For each conversion rate of carbon monoxide, the circulation rate of carbon monoxide produced from tangdo to blast furnace funnel is 32.5% when the carbon monoxide conversion rate is 85%, the circulation rate is 24.9% when the conversion rate is 65%, and the circulation rate is 50% when the conversion rate is 50%. For silver 19.2% and a conversion rate of 35%, the circulation rate was calculated to be 13.4%. The amount of CO gas produced by reacting with the carbon-containing by-products charged inside the reactor installed in the runner and the CO 2 gas blown into the reactor is expressed as a conversion rate, and the amount of CO gas produced by this conversion rate is blown into the blast furnace tuyere. For this purpose, the amount of CO gas that can be replaced with respect to the total amount of air blown into the blast furnace tuyere is the circulation rate in consideration of the heat balance in the blast furnace.
[76]
The effect of reducing the reducing agent cost according to the carbon monoxide conversion rate was about 50 kg/tp pulverized coal when carbon monoxide with a conversion rate of 85% was blown in. At this time, the carbon saving was about 43 kg/tp, the CO 2 reduction effect (CO 2 saving) was about 156kg/tp. However, reintroducing carbon monoxide with a conversion rate of 85% increases the amount of carbon monoxide as the circulation rate is high, and accordingly, the amount of air blown into the blast furnace (Total input gas) is reduced by about 20 Nm 3 /tp, thereby preserving the amount of heat energy. It can be seen that there is a disadvantage of having to increase the oxygen load in order to do this. In addition, CO gas with a conversion rate of 50% showed the closest value to the amount of air blown into the blast furnace, but the bosh gas volume, an index for judging the heat balance at the bottom of the blast furnace, was higher than the case of blowing CO gas with a conversion rate of 30%. low. Accordingly, it can be seen that it is appropriate to re-inject carbon dioxide having a conversion rate of 35% into the blast furnace in consideration of the amount of carbon dioxide gas discharged out of the blast furnace while maintaining the heat balance inside the blast furnace.
[77]
Example 2 - CO gas re-intake amount according to carbon monoxide conversion rate
[78]
An experiment was conducted to find out the amount of CO gas reintroduced into the blast furnace according to the carbon dioxide conversion rate.
[79]
The CO gas conversion rate was changed as shown in Table 2 below, and the amount of flue gas generation and molten iron production were kept constant.
[80]
The amount of CO gas re-injection was calculated according to Equation 1 below.
[81]
[Equation 1] CO gas re-injection amount (Nm 3 /min) = CO2 gas content in flue gas (Nm 3 /ton) X Molten iron output (ton/day) X CO2 gas ratio injected into the tannery (50%)X CO gas conversion rate (%)X(1 day/1440 min)
[82]
[Table 2]
[83]
As can be seen from the above results, when the amount of CO gas re-injection exceeds 1270 Nm 3 /min, the amount of carbon dioxide re-injected increases accordingly, and accordingly, the amount of air blown into the blast furnace decreases, which can be confirmed from Table. As a result, there will be a disadvantage in that the oxygen load must be increased in order to conserve thermal energy as much as the reduced airflow amount. In addition, when the amount of CO gas re-injection is less than 500 Nm 3 /min, the effect of reducing carbon or CO 2 is lowered by that much, and the ultimate purpose of the present invention to achieve energy saving and environmental protection effects is not met.
[84]
Example 3 - Comparison of specific surface area of ​​carbon-containing by-products
[85]
In order to realize the production of carbon monoxide in the carbon dioxide reforming apparatus using radiant heat in the runway, carbon dioxide was blown into reaction tubes each filled with carbon-containing by-products with different specific surface areas as shown in Table 3, respectively, and the conversion rate according to the temperature was measured. is shown in Table 3. It can be seen that the carbon monoxide conversion is increased as the reaction temperature is increased by the radiant heat of the tang, and at the same reaction temperature, it was observed that the conversion rate of carbon-containing by-products having excellent specific surface area was 20% better (see FIG. 3 ). However, re-injection of carbon monoxide with a conversion rate of 85% reduces the amount of air blown into the blast furnace (total input gas) and has the disadvantage of having to increase the oxygen load in order to preserve that much heat energy. it can be seen that
[86]
[Table 3]
[87]
* Conversion rate measurement: the volume of CO produced relative to the volume of CO 2 blown into the reactor
[88]
Example 4 - Comparison of mixing ratio of iron-containing by-products
[89]
Since there are by-products with a low specific surface area among carbon-containing by-products, iron-containing by-products were mixed with carbon-containing by-products and filled in the reaction tube in order to increase the utilization of these by-products and further improve the carbon monoxide conversion rate. Thereafter, the carbon monoxide conversion rate was measured using radiant heat from the tangent. The mixing ratio of the iron-containing by-product is 10% by weight, 20% by weight, 30% by weight, 40% by weight, and 60% by weight based on 100% by weight of the carbon-containing by-product. The results are shown in Table 4 and FIG. 4 . As a result, it was confirmed that the conversion rate was superior to the case in which the iron-containing by-product was added compared to the case in which the iron-containing by-product was not added. In addition, when the ratio of iron-containing by-products was rather large, it was confirmed that the conversion rate was decreased.
[90]
[Table 4]
[91]
The present invention is not limited to the embodiments, but may be manufactured in various different forms, and those of ordinary skill in the art to which the present invention pertains may develop other specific forms without changing the technical spirit or essential features of the present invention. It will be appreciated that this may be practiced. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive.

Claims

[Claim 1]
Collecting carbon dioxide in the flue gas generated in the blast furnace; reforming the carbon dioxide into carbon monoxide; and re-blowing the carbon monoxide into the blast furnace. In the step of re-blowing the carbon monoxide into the blast furnace; in [Equation 1], the CO gas re-injection amount (Nm 3 /min) satisfies 500 or more and 1270 or less. [Equation 1] CO gas re-injection amount (Nm 3 /min) = CO2 gas content in flue gas (Nm 3 /ton) X Molten iron output (ton/day) X CO2 gas ratio injected into the tannery (50%)X CO gas conversion rate (%)X(1 day/1440 min)
[Claim 2]
The method according to claim 1, wherein, in the method for producing molten iron, a CO gas circulation rate of [Equation 2] is 15 to 40%. [Equation 2] CO gas circulation rate (%) = CO gas re-injection amount (Nm 3 /min)/[CO gas content in flue gas (Nm 3 /ton)X molten iron production (ton/day)]X(1440 min/1 day)X100[%]
[Claim 3]
The method of claim 1, wherein the CO gas conversion rate of [Equation 1] is 35% or more to less than 85%.
[Claim 4]
The method of claim 1 , wherein in the step of re-blowing the carbon monoxide into the blast furnace, the temperature of the carbon monoxide is 800° C. or higher.
[Claim 5]
The method of claim 1, wherein in the step of re-blowing the carbon monoxide into the blast furnace, the pulverized coal injection amount (kr/ton-pig) according to the CO conversion rate of [Equation 3] satisfies 100 to 170 kg/ton-pig , molten iron manufacturing method. [Equation 3] Pulverized coal injection according to CO conversion rate (kg/ton-pig) = -0.007*[CO conversion rate (%)] 2 -0.00005*[CO conversion rate (%)]+170.3
[Claim 6]
A mixture of carbon-containing by-product and iron-containing by-product is filled therein, and the mixing ratio of the carbon-containing by-product and the iron-containing by-product is 10 to 50 wt% of the iron-containing by-product based on 100 wt% of the carbon-containing by-product, and carbon dioxide is converted to carbon monoxide Reforming, carbon dioxide reformer.
[Claim 7]
The carbon dioxide reforming apparatus according to claim 6, wherein the carbon-containing by-product has a specific surface area of ​​50 m 2 /g or more.
[Claim 8]
The carbon dioxide reforming apparatus according to claim 6, wherein the carbon component of the carbon-containing by-product is 80 wt% or more, and the iron-containing component of the iron-containing by-product is 50 wt% or more.
[Claim 9]
A device for reforming carbon dioxide in the flue gas generated in a blast furnace, wherein the carbon dioxide reforming device is installed in a melt runway during an ironmaking process.
[Claim 10]
10. The carbon dioxide reforming apparatus according to claim 9, wherein the carbon dioxide reforming apparatus is an apparatus in which one or more apparatuses are installed throughout the melt runway area.
[Claim 11]
The carbon dioxide reforming apparatus according to claim 9, wherein, when there are two or more carbon dioxide reforming units, the reaction tubes are installed and fixedly connected in a bundle form or a mesh network form.
[Claim 12]
10. The carbon dioxide reforming apparatus of claim 9, wherein the melt runway has a cover over the melt, and wherein the carbon dioxide reformer is between the melt and the cover.
[Claim 13]
The carbon dioxide reforming apparatus according to claim 12 , wherein a temperature between the melt and the cover in the melt runway is 900° C. or higher.
[Claim 14]
The carbon dioxide reforming apparatus according to claim 9, wherein the position of the carbon dioxide reformer is adjusted in consideration of the amount of melt in the melt runway.