Slag carbonation system linked to synthetic gas production

Abstract

A slag carbonation system linked to synthetic gas production, according to one embodiment of the present invention, comprises: a synthetic gas production apparatus for producing synthetic gas containing hydrogen and carbon monoxide from a mixed gas containing carbon dioxide; a carbonation apparatus for carbonating slag by using carbon dioxide contained in the synthetic gas obtained from the synthetic gas production apparatus; and a gas-liquid separator for separating moisture contained in the synthetic gas obtained from the carbonation apparatus.

Description

Syngas production linked slag carbonation system

[0001] The present invention relates to a slag carbonation system linked to synthesis gas production.

[0002] Climate change is occurring. As part of efforts to respond to the climate crisis, research is being conducted on technologies to chemically convert emitted carbon dioxide into high-value compounds.

[0003] A representative high-value compound that can be synthesized using carbon dioxide is synthesis gas containing industrially useful hydrogen (H2) and carbon monoxide (CO). Synthesis gas can be used as a reducing gas in steelmaking processes and as a raw material for manufacturing methanol, synthetic fuels, etc. in chemical processes. Synthesis gas can be produced from carbon dioxide through a thermochemical reaction at a high temperature of 650°C or higher.

[0004] In the case of thermochemical synthesis gas production processes, unreacted carbon dioxide remains in the product due to thermodynamic reaction equilibrium limitations. When this residual carbon dioxide synthesis gas is utilized as a raw material for chemical processes such as synthetic fuel production, the non-reaction carbon dioxide remains, reducing process efficiency during pressurization, heating, and compression. Furthermore, it leads to a problem of concentration within the reactor due to reduced reactivity. Additionally, reducing the amount of residual carbon dioxide in the produced synthesis gas requires operation at higher temperatures, which results in high energy input costs and reduced catalyst durability.

[0005] Therefore, there is a need for technology that removes carbon dioxide to produce industrially useful synthesis gas.

[0006] According to one embodiment of the present invention, a slag carbonation system linked to synthesis gas production that is industrially useful can be provided by reducing the residual amount of carbon dioxide.

[0007] According to one embodiment of the present invention, a slag carbonation system linked to synthesis gas production capable of energy-efficient carbon dioxide capture through process linkage can be provided.

[0008] According to one embodiment of the present invention, a slag carbonation system linked to synthesis gas production that can reduce carbon dioxide emissions and create added value can be provided.

[0009] The problems of the present invention are not limited to those described above. A person skilled in the art to which the present invention pertains will have no difficulty understanding additional problems of the present invention from the overall contents of this specification.

[0010] A slag carbonation system linked to synthesis gas production, which is an embodiment of the present invention, comprises: a synthesis gas production device that generates synthesis gas containing hydrogen and carbon monoxide using a mixed gas containing carbon dioxide; a carbonation device that carbonates slag using carbon dioxide contained in the synthesis gas obtained from the synthesis gas production device; and a gas-liquid separator that separates moisture contained in the synthesis gas obtained from the carbonation device.

[0011] The above mixed gas may be derived from byproduct gas.

[0012] The temperature of the above synthesis gas production device may be 650 to 1000℃.

[0013] The above slag may originate from at least one selected from the group consisting of an ironmaking process, a non-ferrous metal smelting process, a cement manufacturing process, and an incineration process.

[0014] The above slag may include at least one selected from magnesium-containing materials and calcium-containing materials.

[0015] The above magnesium-containing material may include MgO.

[0016] The above calcium-containing material may contain CaO.

[0017] It may further include a first heat exchanger that exchanges heat between the mixed gas introduced into the synthesis gas production device and the synthesis gas discharged from the synthesis gas production device.

[0018] It may further include a second heat exchanger that exchanges heat between the mixed gas introduced into the above-mentioned synthesis gas production device and the air generated in the above-mentioned carbonation device.

[0019] It may further include a third heat exchanger that exchanges heat between the mixed gas introduced into the above-mentioned synthesis gas production device and the synthesis gas inside the above-mentioned carbonation device.

[0020] It may further include a fourth heat exchanger that exchanges heat between the slag fed into the carbonation device and the carbonation slag discharged from the carbonation device.

[0021] A slag carbonation system linked to synthesis gas production according to one embodiment of the present invention can be industrially useful as it reduces the residual amount of carbon dioxide.

[0022] A slag carbonation system linked to synthesis gas production according to one embodiment of the present invention can enable energy-efficient carbon dioxide capture through process linkage.

[0023] A slag carbonation system linked to synthesis gas production according to one embodiment of the present invention can reduce carbon dioxide emissions and create added value.

[0024] FIG. 1 is a process diagram illustrating an exemplary slag carbonation system linked to synthesis gas production according to one embodiment of the present invention.

[0025] Preferred embodiments of the present invention will be described below with reference to the attached drawings. However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below.

[0026] In addition, embodiments of the present invention are provided to more fully explain the present invention to those with average knowledge in the relevant technical field.

[0027] In drawings, the shapes and sizes of elements may be exaggerated for clearer explanation.

[0028] In describing the embodiments of the present invention, if it is determined that a detailed description of known technology related to the present invention may unnecessarily obscure the essence of the present invention, such detailed description will be omitted. Furthermore, the terms described below are defined considering their functions in the present invention, and these may vary depending on the intentions or conventions of the user or operator. Therefore, such definitions should be based on the content throughout this specification. The terms used in the detailed description are merely for describing the embodiments of the present invention and should not be limited in any way. Unless explicitly stated otherwise, expressions in the singular form include the meaning of the plural form.

[0029] In this description, expressions such as “include” or “equipped” are intended to refer to certain characteristics, numbers, steps, actions, elements, parts or combinations thereof, and should not be interpreted to exclude the existence or possibility of one or more other characteristics, numbers, steps, actions, elements, parts or combinations thereof other than those described.

[0030] Unless otherwise specifically defined in the specification of the present invention, % units mean weight %.

[0031] In this specification, terms such as 'top', 'upper', 'upper surface', 'lower', 'lower surface', 'lower surface', and 'side surface' are based on the drawings and may actually vary depending on the direction in which the elements or components are arranged.

[0032] Additionally, throughout the specification, when it is said that one part is 'connected' to another part, this includes not only cases where they are 'directly connected,' but also cases where they are 'indirectly connected' with other elements in between.

[0033] The present invention will be described in detail below through each embodiment or example of the invention. It should be noted that each embodiment or example described in this specification is not limited to a single embodiment or example, but may also be combined with other embodiments or examples. Accordingly, the citation of claims in the patent claims is merely an example of an embodiment, and the technical concept of the present invention should not be interpreted as being limited only to a combination with the cited claims; rather, combinations with various claims are also included within the scope of the technical concept of the present invention.

[0034] According to one embodiment of the present invention, a slag carbonation system linked to synthesis gas production can be provided, which is industrially useful as the residual amount of carbon dioxide is reduced, enables energy-efficient carbon dioxide capture through process linkage, reduces carbon dioxide emissions, and creates added value.

[0035] FIG. 1 is a process diagram illustrating an exemplary slag carbonation system linked to synthesis gas production according to one embodiment of the present invention.

[0036] Referring to FIG. 1, a slag carbonation system linked to synthesis gas production, which is an embodiment of the present invention, may include: a synthesis gas production device (200) that produces synthesis gas containing hydrogen and carbon monoxide using a mixed gas containing carbon dioxide; a carbonation device (300) that carbonates slag with carbon dioxide contained in the synthesis gas obtained from the synthesis gas production device (200) and discharges carbonated slag; and a gas-liquid separator (400) that separates moisture contained in the synthesis gas obtained from the carbonation device (300).

[0037] In one embodiment of the present invention, the syngas produced in the syngas production device (200) is a mixed gas of hydrogen and carbon monoxide used as a feedstock for a chemical reaction. The syngas serves as a raw material for various chemical products including ammonia, dimethyl ether, and methanol, and can be an energy source such as for electricity generation.

[0038] The mixed gas introduced into the above-mentioned synthesis gas production device (200) may contain carbon dioxide and may be derived from byproduct gas as well as ordinary air. Examples of byproduct gas may include COG (Cokes oven gas) and FOG (Finex off gas) generated in processes, but are not specifically limited.

[0039] The above mixed gas can be stored in a mixed gas supply unit (100) and can be supplied to the above synthetic gas production device (200) as needed.

[0040] The above synthesis gas production device (200) can produce synthesis gas using a mixed gas containing carbon dioxide. The synthesis gas production reaction, such as the co-electrolysis reaction or the reverse water gas shift (RWGS) reaction, is as follows.

[0041] [Electrolysis]

[0042] CO2 + H2O → H2 + O2

[0043] [Reverse Water Gas Shift Reaction]

[0044] CO2 + H2 → H2O

[0045] In addition, the mixed gas introduced into the above-mentioned synthesis gas production device (200) may further contain methane. The methane dry reforming reaction and methane combined reforming reaction for producing synthesis gas with the mixed gas containing methane are as follows.

[0046] [Methane Dry Reforming]

[0047] CH4 + CO2 → 2H2

[0048] [Methane Complex Reforming]

[0049] 2CH4 + H2O + CO2 → 5H2

[0050] The above mixed gas may further include gases such as water vapor, hydrogen, and nitrogen in addition to carbon dioxide. In this case, the water vapor may originate from water vapor generated by utilizing process waste heat from sources such as steel mills and power plants.

[0051] The temperature of the above-mentioned synthesis gas production device (200) may be 650 to 1,000°C, specifically 700 to 900°C. The operating temperature of the mixed gas production device may affect the reaction rate and equilibrium conversion rate of the synthesis gas conversion reaction. If the operating temperature of the synthesis gas production device (200) is less than 650°C, the synthesis gas production reaction may not proceed easily, and if it exceeds 1,000°C, problems such as high energy consumption and reduced device durability due to high-temperature reaction conditions may occur.

[0052] According to one embodiment of the present invention, the carbon dioxide conversion rate of the synthesis gas production device (200) may be 50 to 100 mol% of the equilibrium conversion rate for each target chemical reaction. The carbon dioxide conversion rate of the synthesis gas production device (200) may be calculated through the following Equation 1.

[0053] [Equation 1]

[0054] CO2 conversion rate = 1 - (moles of CO2 emitted from the synthesis gas production device (200)) / (moles of CO2 supplied to the synthesis gas production device (200))

[0055] In one embodiment of the present invention, the carbonation device (300) may be a device that carbonates slag using carbon dioxide contained in the synthesis gas obtained from the synthesis gas production device (200). Mineral carbonation technology is a useful means of permanently storing carbon dioxide by reacting alkaline earth metal components contained in minerals with carbon dioxide to produce thermodynamically more stable carbonate minerals. Since slag generated in large quantities during the steelmaking process contains a large amount of alkaline earth metals, carbon dioxide emissions can be economically reduced by capturing carbon dioxide through slag carbonation.

[0056] Slag carbonation can be classified into an indirect carbonation method, which extracts alkaline cations and reacts them with carbon dioxide, and a direct carbonation method, which directly reacts alkaline industrial byproducts with carbon dioxide. More specifically, the difference between these two technologies lies in the fact that indirect carbonation aims to produce high-purity CaCO3 by adding a base or acid solution to the slag to leach out active ingredients and then reacting them with carbon dioxide for utilization, whereas direct carbonation aims to treat the slag by directly reacting it with carbon dioxide to immobilize it. Although both methods result in the production of CaCO3 or MgCO3, indirect carbonation necessarily undergoes an leaching process to achieve high purity. Since this process results in lower energy efficiency, it is clearly distinguished from direct carbonation, which does not involve an leaching process, in terms of carbon dioxide treatment.

[0057] The direct carbonation method can reduce the cost of carbon dioxide treatment by allowing reaction with carbon dioxide without undergoing a separate cation extraction process. However, in the case of direct slag carbonation, where gaseous carbon dioxide is dissolved in an aqueous solution and the carbonation reaction proceeds in the liquid phase, continuous operation is difficult because the process of separating the solid and liquid and drying after the carbon dioxide reaction is essential. Additionally, since gaseous carbon dioxide must be operated at a high temperature of 600 to 700°C to react directly with the slag without using an aqueous solution, there is a problem that a large amount of energy input is required.

[0058] Accordingly, one embodiment of the present invention removes carbon dioxide contained in the synthesis gas by a direct carbonation method, and can save energy by discharging high-temperature synthesis gas from the synthesis gas production device (200).

[0059] The above slag may originate from at least one selected from the group consisting of an ironmaking process, a non-ferrous metal smelting process, a cement manufacturing process, and an incineration process.

[0060] The above slag may include at least one selected from a magnesium-containing material and a calcium-containing material, wherein the magnesium-containing material may include MgO and the calcium-containing material may include CaO.

[0061] For example, if MgO is used as the magnesium-containing material and CaO is used as the calcium-containing material, a reaction as shown in Equation 2 below can proceed in the carbonation device (300) to capture carbon dioxide among the synthesis gas components. The following slag carbonation reaction is an exothermic reaction, so heat may be generated in the carbonation device (300).

[0062] [Equation 2]

[0063] CaO + CO2 → CaCO3

[0064] MgO + CO2 → MgCO3

[0065] In the above carbonation device (300), residual carbon dioxide in the synthesis gas can be removed at least 80 mol% through a slag carbonation reaction.

[0066] If carbon dioxide in the product of the synthesis gas production device (200) is utilized without capture, unreacted carbon dioxide in the product remains when linked with the synthetic fuel production process, which reduces process efficiency during the pressurization and heating process, and may cause a problem where carbon dioxide is concentrated in the reactor during the synthetic fuel production process.

[0067] However, in one embodiment of the present invention, high-quality synthesis gas can be produced because carbon dioxide in the product is captured and discharged through slag carbonation.

[0068] The temperature of the carbonation device (300) may be 550 to 750°C, specifically 600 to 650°C. If the temperature of the carbonation device (300) is less than 550°C, the carbonation reaction of the slag may not occur easily, and if it exceeds 750°C, the carbonated alkaline earth metal in the slag may decompose, and the problem of the captured carbon dioxide being re-emitted may occur.

[0069] The carbonation device (300) can receive slag from a slag feeder (310). Additionally, the slag carbonated in the carbonation device (300) can be discharged back to the slag feeder (310).

[0070] The synthesis gas remaining after producing carbonated slag in the above carbonation device (300) can be supplied to a gas-liquid separator (400) to be described later.

[0071] In one embodiment of the present invention, the gas-liquid separator (400) may be a device for separating moisture contained in the synthesis gas obtained from the carbonation device (300).

[0072] The above gas-liquid separator (400) may include a cooling unit for cooling the synthesis gas discharged from the carbonation device (300); and a separation unit for removing water vapor cooled in the cooling unit.

[0073] The above cooling unit is a device for removing water vapor contained in the above synthesis gas, and any device that cools water vapor can be a device commonly used in the industry.

[0074] The above gas-liquid separator (400) separates cooled water vapor from the synthesis gas discharged from the cooling unit and can obtain a synthesis gas mixed with hydrogen, carbon monoxide, carbon dioxide, etc. The molar ratio of carbon dioxide contained in the synthesis gas mixed with hydrogen, carbon monoxide, carbon dioxide, etc. may be less than 5 mol%.

[0075] The above gas-liquid separator (400) is not particularly limited to any conventional gas-liquid separator (400) used in the industry.

[0076] A slag carbonation system linked to synthesis gas production according to one embodiment of the present invention can produce high-quality synthesis gas in which the concentration of carbon dioxide is less than 5 mol% and the molar ratio of hydrogen to carbon monoxide is about 1:1 to 4:1.

[0077] Meanwhile, a slag carbonation system linked to synthesis gas production, which is an embodiment of the present invention, may further include a heat exchanger to heat carbon dioxide and hydrogen supplied from a mixed gas supply unit (100) to a synthesis gas production device (200). The heat exchanger is not particularly limited as long as it is a heat exchanger commonly used in the industry.

[0078] Referring to FIG. 1, the system may further include a first heat exchanger (510) that heat exchanges the mixed gas introduced into the synthesis gas production device (200) and the synthesis gas discharged from the synthesis gas production device (200).

[0079] Referring to FIG. 1, the system may further include a second heat exchanger (520) that exchanges heat between the mixed gas introduced into the synthesis gas production device (200) and the air generated in the carbonation device (300). The second heat exchanger (520) may be placed inside the carbonation device (300) or outside the carbonation device (300). The heat generated in the carbonation device (300) may be heat generated according to a reaction such as Equation 2.

[0080] Referring to FIG. 1, a third heat exchanger (530) that exchanges heat between the mixed gas introduced into the synthesis gas production device (200) and the synthesis gas inside the carbonation device (300) may be further included.

[0081] Referring to FIG. 1, a fourth heat exchanger (540) may be further included to exchange heat between the slag introduced into the carbonation device (300) and the carbonation slag discharged from the carbonation device (300).

[0082] One embodiment of the present invention can save energy by further including a heat exchanger as described above to recover waste heat and efficiently heat the mixed gas supplied to the slag carbonation system linked to synthesis gas production.

[0083]

[0084] Examples

[0085] The present invention will be described in detail below through examples. However, it should be noted that the examples described below are intended merely to illustrate and embody the present invention and are not intended to limit the scope of the present invention. This is because the scope of the present invention is determined by the matters described in the patent claims and matters reasonably inferred therefrom.

[0086]

[0087] 1. Comparative Example 1

[0088] 20 Nm of hydrogen from the mixed gas supply 3 / h, carbon dioxide 10 Nm3 1 / h was supplied to the synthesis gas production unit, and synthesis gas was produced through a reverse water-gas shift reaction by operating the synthesis gas production unit at a pressure of 1 bar and a temperature of 700°C, with a carbon dioxide conversion rate of 60 mol%.

[0089] The synthesized synthesis gas was supplied to a gas-liquid separator to remove steam and obtain synthesis gas.

[0090] The flow rates of each component contained in the syngas discharged from the syngas production unit and the flow rates and molar ratios of each component obtained from the gas-liquid separator are shown in Table 1 below.

[0091] 2. Comparative Example 2

[0092] Syngas was produced through a reverse water-gas shift reaction by operating the synthesis gas production system in the same manner as Comparative Example 1, except that 15 Nm3 / h of hydrogen and 10 Nm3 / h of carbon dioxide were supplied to the synthesis gas production device from the mixed gas feeder, and the carbon dioxide conversion rate was 53 mol%.

[0093] The flow rates of each component contained in the syngas discharged from the syngas production unit and the flow rates and molar ratios of each component obtained from the gas-liquid separator are shown in Table 1 below.

[0094] 3. Example 1

[0095] 20 Nm of hydrogen from the mixed gas supply 3 / h, carbon dioxide 10 Nm 3 1 / h was supplied to the synthesis gas production unit, and synthesis gas was produced through a reverse water-gas shift reaction by operating the synthesis gas production unit at a pressure of 1 bar and a temperature of 700°C, with a carbon dioxide conversion rate of 60 mol%.

[0096] The synthesized synthetic gas was supplied to a carbonation unit containing iron slag containing CaO and MgO, and the carbonation unit was operated at 650°C. Through the slag carbonation reaction, 90 mol% of carbon dioxide in the product was captured.

[0097] Synthetic gas discharged from the carbonation unit was supplied to a gas-liquid separator to remove steam and obtain synthetic gas.

[0098] The flow rates of each component contained in the syngas discharged from the syngas production unit, the flow rates of each component contained in the syngas discharged from the carbonation unit, and the flow rates and molar ratios of each component obtained from the gas-liquid separator are shown in Table 1 below.

[0099] 4. Example 2

[0100] 15 Nm of hydrogen from the mixed gas supply 3 / h, carbon dioxide 10 Nm 3 1 / h was supplied to the synthesis gas production unit, and synthesis gas was produced through a reverse water-gas shift reaction by operating the synthesis gas production unit at a pressure of 1 bar and a temperature of 700°C, and the carbon dioxide conversion rate was 53 mol%.

[0101] The synthesized synthetic gas was supplied to a carbonation unit containing iron slag containing CaO and MgO, and the carbonation unit was operated at 650°C. Through the slag carbonation reaction, 90 mol% of carbon dioxide in the product was captured.

[0102] Synthetic gas discharged from the carbonation unit was supplied to a gas-liquid separator to remove steam and obtain synthetic gas.

[0103] The flow rates of each component contained in the syngas discharged from the syngas production unit, the flow rates of each component contained in the syngas discharged from the carbonation unit, and the flow rates and molar ratios of each component obtained from the gas-liquid separator are shown in Table 1 below.

[0104] Flow rate of each component of the syngas discharged from the syngas production unit (Nm 3 / hr) Flow rate of each component of the synthesis gas discharged from the carbonation unit (Nm 3 / hr) Flow rate of each component of the synthesis gas discharged from the gas-liquid separator (Nm 3 / hr) Content of each component of synthesis gas discharged from the gas-liquid separator (mol%) H2COCO2H2OH2COCO2H2OH2COCO2H2COCO2 Example 1 146461460.461460.469292 Example 2 9.75.34.75.39.75.30.55.39.75.30.562343 Comparative Example 1 14646-1464582517 Comparative Example 29.75.34.75.39.75.34.7492724

[0105]

[0106] Referring to Table 1 above, the content of hydrogen and carbon dioxide in the mixed gas fed into the synthesis gas production device is the same for Example 1 and Comparative Example 1, and Example 2 and Comparative Example 2, but it can be seen that the content of carbon dioxide remaining in the final synthesis gas and the molar ratio of hydrogen and carbon monoxide differ significantly depending on the presence or absence of the carbonation device.

[0107] (Explanation of symbols)

[0108] 100: Mixed gas supply unit 200: Syngas production unit

[0109] 300: Carbonation unit 310: Slag feeder

[0110] 400: Gas-liquid separator 510: First heat exchanger

[0111] 520: 2nd heat exchanger 530: 3rd heat exchanger

[0112] 540: 4th heat exchanger

Claims

1. A synthesis gas production device that produces synthesis gas containing hydrogen and carbon monoxide using a mixed gas containing carbon dioxide; A carbonation device for carbonating slag with carbon dioxide contained in the synthesis gas obtained from the above synthesis gas production device; and A slag carbonation system linked to synthesis gas production, comprising a gas-liquid separator for separating moisture contained in the synthesis gas obtained from the carbonation device.

2. In Paragraph 1, A slag carbonation system linked to synthesis gas production, wherein the above-mentioned mixed gas is derived from byproduct gas.

3. In Paragraph 1, A slag carbonation system linked to synthesis gas production, wherein the temperature of the synthesis gas production device is 650 to 1000℃.

4. In Paragraph 1, A slag carbonation system linked to synthesis gas production, wherein the above slag is derived from at least one selected from the group consisting of an ironmaking process, a non-ferrous metal smelting process, a cement manufacturing process, and an incineration process.

5. In Paragraph 1, A slag carbonation system linked to synthesis gas production, wherein the slag comprises at least one selected from a magnesium-containing material and a calcium-containing material.

6. In Paragraph 5, The above magnesium-containing material is a slag carbonation system linked to synthesis gas production, comprising MgO.

7. In Paragraph 5, The above calcium-containing material is a slag carbonation system linked to synthesis gas production, containing CaO.

8. In Paragraph 1, A slag carbonation system linked to synthesis gas production, further comprising a first heat exchanger for heat exchange between a mixed gas fed into the synthesis gas production device and a synthesis gas discharged from the synthesis gas production device.

9. In Paragraph 1, A slag carbonation system linked to synthesis gas production, further comprising a second heat exchanger for heat exchange between the mixed gas fed into the synthesis gas production device and the air generated in the carbonation device.

10. In Paragraph 1, A slag carbonation system linked to synthesis gas production, further comprising a third heat exchanger that exchanges heat between the mixed gas fed into the synthesis gas production device and the synthesis gas inside the carbonation device.

11. In Paragraph 1, A slag carbonation system linked to synthesis gas production, further comprising a fourth heat exchanger for heat exchange between slag fed into the carbonation device and carbonation slag discharged from the carbonation device.

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