Multistage catalytic reaction system for simultaneous conversion of hydrocarbons of various carbon numbers

Abstract

The present invention relates to a multi-stage catalytic reaction system for the simultaneous conversion of hydrocarbons having various carbon numbers. More specifically, the invention relates to a multi-stage catalytic reaction system that produces hydrogen or syngas, which is a mixture of hydrogen and carbon monoxide, by mixing and reacting carbon dioxide in a certain ratio with hydrocarbons having various carbon numbers ranging from C1 to C6, including paraffinic (CnH2n+2), naphthenic (CnH2n), olefinic (CnH2n), diolefinic (CnH2n-2), and acetyleneic (CnH2n-2) hydrocarbons. Through the multi-stage reaction system of the present invention, which maintains different reaction conditions for each reaction zone, hydrocarbon reactants of various compositions emitted in actual industry can be processed collectively in a single process, thereby significantly reducing process costs and enabling the production of high-value hydrogen or syngas with a high yield.

Description

Technology Field

[0001] The present invention relates to a multi-stage catalytic reaction system for the simultaneous conversion of hydrocarbons having various carbon numbers, and more specifically, to a catalytic reaction system for the production of hydrogen and syngas through one-step dry reforming of mixed hydrocarbons having various carbon numbers, wherein high-value hydrogen or syngas can be obtained with a high yield by processing hydrocarbons mixed with various components in a single multi-stage process without undergoing a separate separation process through a multi-stage reactor in which reaction conditions are set differently for each reaction zone. Background Technology

[0002] Dry reforming is a reaction that produces hydrogen and carbon monoxide using methane and carbon dioxide, which are representative greenhouse gases, as reactants, and is one of the most effective processes for carbon neutrality. Conventional dry reforming has primarily targeted methane (CH4), which has one carbon atom; however, byproduct gases emitted from industrial processes actually contain various hydrocarbons with two or more carbon atoms. When dry reforming is carried out using carbon dioxide along with these byproduct gases as reactants, useful hydrogen and carbon monoxide can be obtained by utilizing greenhouse gases, making it a very useful technology for addressing global warming.

[0003] In particular, since the carbon dioxide used as a reactant in the dry reforming process is sourced from carbon dioxide captured from sources such as industrial byproduct gases, this process is highly useful not only for achieving carbon neutrality and addressing climate change, but also for reducing raw material and process costs for hydrogen and synthesis gas.

[0004] [Reaction Equation 1]

[0005] CH4 + CO2 → 2H2 + 2CO, H 298K = +247kJ / mol

[0006] C2H6 + 2CO2 → 3H2 + 4CO, H 298K= +429kJ / mol

[0007] C3H8 + 3CO2 → 4H2 + 6CO, H 298K = +620kJ / mol

[0008] C4H 10 + 4CO2→ 5H2+ 8CO, H 298K = +816kJ / mol

[0009] C5H 12 + 5CO2→ 6H2+ 10CO, H 298K = +1036kJ / mol

[0010] C6H 14 + 6CO2→ 7H2+ 12CO, H 298K = +1235kJ / mol

[0012] The above [Reaction Equation 1] represents the dry reforming reaction equation for alkane hydrocarbons having 1 to 6 carbon atoms. The dry reforming reactions of representative hydrocarbons, such as the alkane series methane, ethane, propane, butane, pentane, and hexane, are all endothermic reactions and require an external heat supply to proceed. The required reaction temperature tends to increase as the number of carbon atoms decreases. Paraffin hydrocarbons composed of single bonds tend to have higher reaction temperatures compared to hydrocarbons composed of olefin series (containing one double bond), acetylene series (containing one triple bond), diolefin series (containing two double bonds), and naphthene series (cyclic compounds). Therefore, for the simultaneous conversion of mixed gases with various carbon atoms, applying an integrated reaction system composed of multi-stage reactors maintained at different temperatures is effective for reducing process costs and facilitates operation.

[0013] In actual industrial applications, C1, C2, C3, and C4 hydrocarbons are emitted together as byproduct gases, and depending on the process, C5-C6 hydrocarbons with a higher number of carbon atoms are also emitted as a mixture. If these are separated individually before being fed into the treatment process, the process costs are enormous, and a vast area (site) is required for the construction of the process. To process byproduct gases mixed with various hydrocarbons in a single step without separate pretreatment or separation processes, a series of catalytic conversion processes can be applied by sequentially connecting multi-stage catalytic reaction systems with different process conditions applied according to the number of carbon atoms and bonding types (paraffin series, olefin series, acetylene series, diolefin series, naphthene series, etc.) of the hydrocarbons contained in the reactants. This allows the reactants containing various hydrocarbons such as C1-C6 to be converted into hydrogen and carbon monoxide through a single process.

[0014] For example, when converting hydrocarbon reactants with a large carbon number, such as C6, compounds with a small carbon number, such as C1, C2, C3, and C4, may be generated as byproducts. In this invention, by arranging a multi-stage reaction system such that the operating temperature increases towards the downstream stage, reactants with a large carbon number are converted preferentially, and byproducts with a small carbon number generated in this process are sequentially processed in subsequent connected reactors. Consequently, it offers the ease of ultimately obtaining only the synthesis gas composition. Additionally, the multi-stage catalytic reaction system has the added advantage of further reducing process costs for preheating reactants, as the gas flow is directly fed into the next connected reactor while still heated to the reaction temperature in the previous reactor.

[0015] The products obtained by this method can be used for the production of hydrogen and carbon monoxide, Fischer-Tropsch synthesis, methanol synthesis, ammonia synthesis, and synthetic natural gas production, as well as for conversion into high-value basic chemicals such as polyolefins and polyurethanes.

[0016] Although an integrated multi-stage reactor is disclosed in Prior Art 1, it differs from the present invention in that the reaction applied is opposite to that of the present invention, that is, it is applied to a reaction in which carbon monoxide or carbon dioxide is reacted with hydrogen to synthesize methane, and the temperature of each reaction zone is gradually lowered according to the direction of gas flow.

[0017] Prior art documents 2 and 3 disclose a multi-stage water-gas reaction device, which is a device for producing hydrogen by reacting carbon monoxide with water, and differs from the present invention in that the reaction applied is different and the temperature is lowered along the direction of the reaction gas flow.

[0018] Although prior art document 4 also discloses a multi-stage synthesis gas production reactor, unlike the present invention, it is applied to a complex reforming reaction in which steam is introduced together with a hydrocarbon feedstock, and differs in that it is a reactor in which different catalysts, namely a pre-reforming catalyst layer, a precious metal enhancement catalyst layer, and a nickel-based catalyst layer, are sequentially configured for each reaction zone. Prior art literature

[0019] Korean Published Patent No. 10-2020-0048816, Korean Published Patent No. 10-2011-0015148, Korean Published Patent No. 10-2020-0000749, Korean Published Patent No. 10-2009-0011299 The problem to be solved

[0020] The objective of the present invention is to provide a multi-stage reaction system in which a plurality of reaction zones, each having different operating conditions, are connected in series, as an alternative to the conventional process of separating hydrocarbons by composition and feeding them into different reactors, in a dry reforming reactor that produces hydrogen or synthesis gas by reacting a mixture of hydrocarbons having various carbon numbers with carbon dioxide. means of solving the problem

[0021] To achieve the above objective, the present invention comprises: a reactant supply unit for supplying a reactant comprising a hydrocarbon and carbon dioxide; a gas reaction unit having a plurality of reaction zones connected in series for reacting the reactant on a catalyst; and a product gas discharge unit for discharging a gas generated by passing through the gas reaction unit; wherein the hydrocarbon may include a substituent, and the hydrocarbon is a paraffinic (C) having n of 1 to 6. n H 2n+2 ) hydrocarbons, naphthenic types (C) where n is 3 to 6 n H 2n ) hydrocarbons, olefins having n of 2 to 6 (C n H 2n ) hydrocarbons, diolefins in which n is 3 to 6 (C n H 2n-2 ) hydrocarbons and acetylene-based (C) having n of 2 to 6 n H 2n-2 A multi-stage catalytic reaction system for the simultaneous conversion of hydrocarbons having various carbon numbers is provided, wherein two or more mixtures selected from a group of hydrocarbons or any one in which n is 2 to 6 are supplied, the reactor included in the gas reaction unit includes the same catalyst for each reaction zone, the gas reaction unit is divided into a number of reaction zones corresponding to the maximum number of carbons (n) of the hydrocarbon included in the reactant, and the temperature of the reaction zone at the rear is higher than that of the reaction zone at the front. Effects of the invention

[0022] The multistage catalytic reaction system according to the present invention is a C1 to C6 paraffinic (C1 to C6) mixed gas emitted in actual industry. n H 2n+2 ), naphthenic (C n H 2n ), olefin-based (C n H 2n ), diolefin series (C n H 2n-2 ), acetylene-based (C n H 2n-2Since hydrocarbons are introduced simultaneously to carry out the reaction, it is possible to minimize the gas separation process, which is performed as a pretreatment process before the reaction process.

[0023] Furthermore, the multi-stage catalytic reaction system of the present invention controls reaction conditions such as temperature, flow rate, and pressure at each stage, thereby enabling appropriate chemical reactions for each substance and avoiding the use of energy beyond what is necessary; this enables the more economical production of synthesis gas and hydrogen compared to conventional catalytic reaction systems for hydrocarbon conversion.

[0024] In addition, the multi-stage catalytic reaction system of the present invention can bring about the effect of increasing the efficiency and economic feasibility of the overall process by reducing heat waste and minimizing gas treatment processes, as the heated product from each reactor is transferred to the next reactor.

[0025] However, the effects of the present invention are not limited to those mentioned above, and other unmentioned effects will be clearly understood by a person skilled in the art from the description below. Brief explanation of the drawing

[0026] Figure 1 is a schematic diagram of the process flow of a catalytic reaction system according to a comparative experimental example of the present invention and a graph showing the results of the dry reforming reaction in the system. FIG. 2 is a flowchart of a dry reforming reaction of a raw material mixed with hydrocarbons of various carbon numbers according to one embodiment of the present invention. FIG. 3 shows a schematic diagram of a six-stage catalytic reaction system for a dry reforming reaction of C1-C6 hydrocarbons according to one embodiment of the present invention. FIG. 4 shows a schematic diagram of a six-stage catalytic reaction system for dry reforming C1-C6 hydrocarbons according to another embodiment of the present invention. FIG. 5 is a schematic diagram of the process flow of a multi-stage catalytic reaction system for dry reforming C1-C6 mixed hydrocarbons according to an embodiment of the present invention and a graph showing the amount of each product obtained as a result of the dry reforming reaction in the system. Specific details for implementing the invention

[0027] Hereinafter, the specific details of the present invention will be described in detail with reference to the drawings. Unless otherwise defined, technical or scientific terms used in this description represent the meaning commonly understood by those skilled in the art to which the invention pertains. In describing the invention, if it is determined that a detailed description could obscure the essence of the invention, such detailed description is omitted.

[0028] In describing the components of the present invention, when terms such as “includes,” “has,” or “consists of,” other parts may be added unless “-only” is used. When a component is expressed in the singular, it may include a plural form unless otherwise explicitly stated.

[0030] First, with reference to FIG. 1, a conventional dry reforming reaction system for mixed hydrocarbons and the dry reforming reaction results thereof will be described.

[0031] Figure 1 shows a conventional dry reforming reaction system for mixed hydrocarbons and a graph of the dry reforming reaction results.

[0032] Conventional dry reforming reaction systems for mixtures of hydrocarbons with various carbon numbers carried out the reforming reaction in multiple individual reactors equipped with catalysts, reaction temperatures, and pressures suitable for reforming each hydrocarbon component with a different carbon number. Consequently, the hydrocarbon mixture must undergo a process to separate it into hydrocarbons of each carbon number before being fed into the reactors; however, this process has the disadvantage of requiring a large site and substantial costs. Methods for separating the composition of the mixed gas into its respective components include utilizing differences in boiling points, using membranes, or using adsorbents via pressure swing adsorption (PSA), but are not limited to these methods.

[0033] Referring to the bottom of Figure 1, for example, when C6 hydrocarbons pass through a reforming reactor, not all C6 hydrocarbons are directly converted into CO and H2, and a large amount of residue of C1-C5 hydrocarbons with fewer carbon atoms than C6 remains, which has the problem that an additional process for post-treatment is required.

[0034] In addition, as explained above, there is a disadvantage in that it requires significant facility investment and massive operating costs, as a multi-stage separation process is additionally required to separate various unreacted hydrocarbons remaining in each reactor after the reaction is finished, in addition to the need for energy to operate the large-scale separation process and to separate the various unreacted hydrocarbons remaining in each reactor after the reaction is finished.

[0036] FIG. 2 is a paraffin-based (C) according to one embodiment of the present invention. n H 2n+2 ), naphthenic (C n H 2n ), olefin-based (C n H 2n ), diolefin series (C n H 2n-2 ), acetylene-based (C n H 2n-2This shows a flowchart of a dry reforming reaction using a gas in a single or mixed state as a raw material, which is a hydrocarbon having various carbon numbers including ) etc.

[0038] FIG. 3 is a schematic diagram of a six-stage catalytic reaction system configured as an integral unit when supplying C1-C6 hydrocarbons as reactants according to one embodiment of the present invention.

[0040] One aspect of the present invention is a paraffinic (C n H 2n+2 ), naphthenic (C n H 2n ), olefin-based (C n H 2n ), diolefin series (C n H 2n-2 ), acetylene-based (C n H 2n-2 The present invention relates to a multi-stage catalytic reaction system for finally producing synthesis gas composed of hydrogen and carbon monoxide through a one-step process by passing a mixture of carbon dioxide and one or more types of hydrocarbons, including ) etc., through a dry reforming reaction system composed of multi-stage reactors. At this time, the hydrocarbon is a paraffinic (C) type in which n is 1 to 6 n H 2n+2 ) hydrocarbons, naphthenic types (C) where n is 3 to 6 n H 2n ) hydrocarbons, olefins having n of 2 to 6 (C n H 2n ) hydrocarbons, diolefins in which n is 3 to 6 (C n H 2n-2 ) hydrocarbons and acetylene-based (C) having n of 2 to 6 n H 2n-2 ) It is a mixture of two or more selected from the group consisting of hydrocarbons, or any one where n is 2 to 6.

[0041] In the multi-stage catalytic reaction system according to the present invention, the number of reaction zones and operating conditions such as temperature, pressure, residence time, and flow rate of each reaction zone can be appropriately controlled according to the type and number of carbon atoms of the hydrocarbons contained in the raw material hydrocarbons, and by controlling such operating conditions, the composition of the product gas at the outlet of each reaction zone, the composition ratio of the product gas at the final product outlet, and the conversion rate can be controlled.

[0042] For example, the multi-stage catalytic reaction system of the present invention may be divided into a number of reaction zones corresponding to the number of carbon atoms (n) of the component with the largest number of carbon atoms among the input hydrocarbon mixture raw materials.

[0043] Specifically, referring to FIG. 3, the multi-stage catalytic reaction system of the present invention may include: a reactant supply unit (2) for supplying reactants including hydrocarbons and carbon dioxide; a gas reaction unit (8) in which a plurality of reaction zones (A to F) for reacting the reactants on a catalyst layer (10) are connected in series; and a generated gas discharge unit (9) for discharging gas generated by passing through the gas reaction unit (8). In the multi-stage catalytic reaction system of the present invention, the reactant supply unit (2) is a device for supplying hydrocarbons and carbon dioxide, which are reactants used in the dry reforming reaction of the present invention, to a reaction unit (8) equipped with a catalyst layer (10), and the reactants may be in a liquid or gaseous state. If the reactants are in a liquid state, they may be heated above a vaporization temperature for reaction and injected into a reactor in a gaseous state. Although not shown in FIG. 3, conventional devices such as a flow meter and a flow control device for controlling the reactant input speed may be additionally installed in the reactant supply unit.

[0044] The gas supplied from the above reactant supply unit (2) flows into a multi-stage catalytic reactor, and the flow of the supplied gas can flow perpendicularly to the catalyst layer (10) contained in the reactor.

[0045] In the multi-stage catalytic reaction system of the present invention, in the reaction zone of each stage, unreacted material and product (H2+CO) discharged from the reaction zone of the preceding stage are introduced into the reaction zone of the subsequent stage connected in series, thereby converting the unreacted material into hydrocarbons and products with a smaller number of carbon atoms under process conditions different from the preceding stage, so that the final conversion rate and the yield of the final product composition of hydrogen (H2) and carbon monoxide (CO) can be maximized.

[0046] The reaction zone included in the above gas reaction section may include a catalyst layer (10) for promoting the progress of the reaction, and the catalysts in all reaction zones may be the same or different, preferably the catalysts in all reaction zones may be the same.

[0047] In addition, the above reaction zone may be characterized by having a higher temperature in the downstream reaction zone than in the upstream reaction zone. Generally, as the carbon number increases, the temperature conditions suitable for the reforming reaction tend to decrease; therefore, by arranging the reaction zones in a sequence where the temperature increases towards the downstream end, unreacted hydrocarbons with a small carbon number or those generated as byproducts in the upstream end are converted into final products in the downstream reaction zone with a higher temperature, thereby minimizing reaction residues and maximizing yield.

[0048] Furthermore, since the gas flow introduced from the upstream stage is heated above a certain temperature, this offers the advantage of facilitating thermal management in a multi-stage reaction system where the temperature increases as it moves toward the downstream stage, while simultaneously minimizing operating costs for heating. Additionally, by connecting reaction zones with different operating conditions in series, a high yield of product can be obtained through a one-step process without a separate step to separate the hydrocarbon mixture generated at each stage, resulting in a significant increase in process efficiency.

[0050] In the multistage catalytic reaction system of the present invention, the hydrocarbon included in the reactant is paraffinic (C n H 2n+2 ), naphthenic (Cn H 2n ), olefin-based (C n H 2n ), diolefin series (C n H 2n-2 ), acetylene-based (C n H 2n-2 It may be any one or more mixtures selected from the group consisting of ), etc., preferably n may be 1 to 6, and more preferably n may be 1 to 4. For example, methane (CH4), acetylene (C2H2), ethylene (C2H4), ethane (C2H6), propine (C3H4), propylene (C3H6), propane (C3H8), butine (C4H6), butene (C4H8), and butane (C4H 10 It may include one or more mixtures selected from the group consisting of, etc., but is not limited thereto. The hydrocarbon may include one having a functional group, for example, ethanol (C2H5OH) having an -OH group.

[0051] The hydrocarbons supplied to the present invention may be obtained from by-product gases or waste gases discharged from actual industrial processes such as the steel industry, petrochemical industry, oil refining industry, power plants, and painting processes. By-product gases discharged from conventional industrial processes contain various C2-C4 hydrocarbons in addition to C1 hydrocarbons with one carbon atom, and depending on the process, C5-C6 hydrocarbon components with more carbon atoms may be mixed in.

[0052] In the multi-stage catalytic reaction system of the present invention, the input ratio of carbon dioxide to hydrocarbon included in the reactants may be 1:1 to 10:1 based on the total number of carbon atoms of each. It is desirable to control the reactant composition within the above range so that unreacted residues are reduced and the concentration of synthesis gas, which is the product, is increased, thereby obtaining high-purity hydrogen and carbon monoxide products. The carbon dioxide may be introduced together with the hydrocarbon or may be introduced from a separate source. Furthermore, the entire amount of carbon dioxide required for the dry reforming of the input hydrocarbon may be introduced through the reactant supply unit, or it may be introduced at the downstream end of each reaction zone other than the final reaction zone among the plurality of reaction zones.

[0053] In addition, to control the concentration of carbon dioxide and hydrocarbons included in the reactants and to control the reaction rate, an inert gas (nitrogen, argon, helium, etc., also called a carrier gas) may be additionally supplied together with carbon dioxide to the reactant supply section or the CO2 additional input section (11) at the rear end of each reaction zone. However, to prevent an increase in costs such as raw material costs and separation / purification costs due to the use of carrier gas, it may be advantageous not to use carrier gas if possible.

[0055] In the multistage catalytic reaction system of the present invention, the gas reaction unit comprises a multistage reactor in which a plurality of reaction zones are connected in series and integrated, and the catalyst included in each reactor reacts with hydrocarbons and carbon dioxide to produce a synthesis gas composed of hydrogen and carbon monoxide.

[0056] The above reactor may be a reactor made of quartz, metal (alloy), or ceramic material that can prevent shape deformation caused by high-temperature heat.

[0057] The above reactor may also remove impurities present inside the reactor that inhibit the reaction before the reaction begins by supplying an inert gas, such as nitrogen (N2), argon (Ar), or helium (He), into the reactor. The inert gas is 40-100 cm based on a 20 mm diameter quartz tube reactor. 3 It is preferable to supply at a rate of / min for 30 to 60 minutes, and it is preferable to increase the flow rate of the inert gas when the diameter of the reactor increases. In addition, by heating the inert gas introduced into the reactor to a high temperature and supplying it, the effect of removing impurities can be enhanced, and the reactor temperature can also be increased. At this time, it is preferable that the heating rate of the reactor be 0.5 to 30℃ / min. For example, the temperature can be raised using the inert gas to the temperature of the first reaction zone, which has the lowest reaction temperature among the various reaction zones of the reactor, and subsequent zones with higher reaction temperatures can be raised to the desired temperature of each reaction zone using heating wires and temperature control devices provided in each reaction zone.

[0058] The catalyst included in each of the above reaction zones may additionally undergo a reduction step in a hydrogen atmosphere of 300-800°C prior to use in the reaction to maximize catalyst performance. This reduction step can be carried out by supplying hydrogen into the reactor, and the concentration of the supplied hydrogen and the reduction rate can be controlled by supplying an inert gas along with it. In the mixture of hydrogen and inert gas, it is preferable that the hydrogen be contained in 1-20 vol%, and more preferably 3-10 vol%. Additionally, the mixture of hydrogen and inert gas is 10-150 cm based on a 20 mm diameter quartz tube reactor. 3 It is preferable to supply at a rate of / min for 30 to 360 minutes, but it is preferable to increase the gas flow rate when the diameter of the reactor increases.

[0059] It is preferable that each of the above reaction zones be operated at atmospheric pressure, but is not limited thereto; considering the reaction rate and yield, reduced pressure below atmospheric pressure (≤760 Torr) or pressurized conditions above atmospheric pressure (≥760 Torr) may be applied.

[0061] In the multistage catalytic reaction system of the present invention, the gas reaction section may include a number of reaction zones equal to or greater than the maximum number of carbon atoms of the hydrocarbons contained in the reactants. That is, a paraffinic system having n carbon atoms (C n H 2n+2 ), naphthenic (C n H 2n ), olefin-based (C n H 2n ), diolefin series (C n H 2n-2 ), acetylene-based (C n H 2n-2 ) When hydrocarbons are present in the reactants, the gas reaction unit may additionally be connected in series with one or more reaction zones equipped with optimized operating conditions for the conversion of other aromatic hydrocarbon reactants. Even in this case, each reaction zone must be connected in order of operating temperature from low to high to obtain the maximum conversion rate of the reactants and the yield of the desired product.

[0062] In the multi-stage catalytic reaction system of the present invention, the temperature of each reaction zone of the gas reaction section may be 25 to 1500°C, and the number of reaction zones and the range of reaction temperatures of each reaction zone may be appropriately adjusted depending on the type of catalyst used in the reaction or the type of hydrocarbon included in the reactant.

[0063] For example, in the case of an atmospheric pressure reaction process using nickel as a catalyst and a hydrocarbon containing a mixture of CH4, C2H6, and C3H8 as a reactant, it is desirable to control the first reaction zone to 500-600°C, the second reaction zone to 600-700°C, and the third reaction zone to 700-950°C to maximize the conversion rate and the yield of the product.

[0065] In the multi-stage catalytic reaction system of the present invention, the gas reaction unit (8) may include a temperature control device for each reaction zone so that the temperature conditions of each reaction zone can be controlled differently.

[0066] The temperature control device (6) of each reaction zone is a known technology, for example, by measuring the temperature of the catalyst layer of each reaction zone using a thermocouple, and the temperature control device can adjust the temperature of each reaction zone to a set value by controlling the amount of electricity input of a heating device, for example, an electric heating element (heating wire). The temperature control device is not particularly limited as long as it is a device commonly used, and may include, for example, an electric furnace.

[0067] In addition, in the multi-stage catalytic reaction system of the present invention, the gas reaction unit (8) may include a pressure regulating device for each reaction zone so that the pressure conditions of each reaction zone can be adjusted differently. The pressure regulating device is not particularly limited as long as it is a device commonly used.

[0068] In addition, the multistage catalytic reaction system of the present invention may additionally include, although not mandatory, a gas analyzer (7) for analyzing the emitted gas, such as a gas chromatograph or a mass spectrometer, preferably at the downstream end of each reaction zone of the reaction section.

[0069] Meanwhile, if necessary, the product gas composition of each reaction zone can be checked in real time through the gas analyzer (7), and the amount of CO2 consumed in the preceding reaction zone and the amount of CO2 required for the reaction in the next reaction zone can be calculated. Then, the reaction can be carried out by additionally introducing the required amount of CO2 into the reaction zone through the CO2 additional input unit (11), thereby maximizing the conversion rate of the hydrocarbon reactant. At this time, if necessary, an inert gas such as Ar, He, and / or N2 may be introduced together with CO2 for the purpose of dilution or flow rate control.

[0070] In the multistage catalytic reaction system of the present invention, the arrangement order of the reaction zones can be arranged in such a way that the inner diameter of the reactor included in the reaction zone decreases as it moves toward the rear end, or in the reverse order. For a small-scale laboratory-scale system, the diameter of the reactor is preferably 5-100 mm, and for a pilot-scale system or larger, the inner diameter of the reactor can be set differently to 100 mm-1 m or more to control the flow rate and residence time in each reactor. As the diameter of the reactor increases, the amount of reactant introduced through the reactor may increase. Furthermore, as summarized in Reaction Equation 1 above, since the hydrocarbon conversion reaction is a reaction in which the volume of the product increases relative to the reactant, if the diameter of the reactor decreases toward the rear end, the flow rate of the reactant and the pressure inside the reactor may increase significantly. On the other hand, if the diameter of the reactor increases toward the rear end, the flow rate of the gas passing through the reactor may decrease or remain similar from the front end to the rear end.

[0072] In the multistage catalytic reaction system of the present invention, the catalyst included in the reactor may be used in the form of a single-composition catalyst composed of any one selected from the group consisting of nickel (Ni), lanthanum (La), gold (Au), cerium (Ce), ruthenium (Ru), rhodium (Rh), palladium (Pd), cobalt (Co), iron (Fe), iridium (Ir), chromium (Cr), gallium (Ga), tungsten (W), rhenium (Re), niobium (Nb), molybdenum (Mo), magnesium (Mg), manganese (Mn), copper (Cu), titanium (Ti), lithium (Li), yttrium (Y), ytterbium (Yb), boron (B), barium (Ba), silver (Ag), and platinum (Pt), or in the form of an alloy or intermetallic compound containing two or more components, and may be used in the reaction in an oxidized state or a reduced state.

[0073] In addition, when the catalyst component is supported in a particulate state to maximize the reaction surface area of ​​the catalyst, one or more supports selected from the group consisting of alumina (Al2O3), silica (SiO2), titania (TiO2), zirconia (ZrO2), ceria (CeO2), magnesia (MgO), lantania (La2O3), barium (BaO), silicon carbide (SiC), carbon black, activated carbon, graphene oxide, graphite, metal-organic frameworks (MOFs), zeolites, hydroxyapatite (HAP), MCM-41, SBA-15, and carbon nanotubes may be used as the support for the catalyst.

[0074] The amount of catalyst supported on the support can be appropriately controlled during the catalyst manufacturing process, and after catalyst manufacturing, the amount or concentration of the catalyst can also be controlled by mixing a support without supporting the catalyst.

[0076] With reference to FIG. 4, a catalytic reaction system for dry reforming of C1-C6 hydrocarbons according to another embodiment of the present invention will be described.

[0077] Here, regarding the configuration of the catalytic reaction system for dry reforming C1-C6 hydrocarbons according to the present embodiment, the parts that are functionally identical to those previously described in relation to Fig. 3 are omitted from the description, and the content of the description related to Fig. 3 is used by reference.

[0078] Referring to FIG. 4, the gas reaction unit (8) of the present embodiment is composed of six separated reaction zones (A to F), and the reactor, heating wire, thermocouple, temperature control device, etc. constituting each reaction zone are functionally identical to those described in FIG. 3.

[0079] In this embodiment, reaction zones A through F are connected by reaction zone connecting parts (12-1 to 12-5) that connect the outlet of each reaction zone to the inlet of the next reaction zone, and the products of the immediate reaction zone are moved to the next reaction zone through each reaction zone connecting part. At this time, each reaction zone connecting part may optionally be equipped with a temperature control part (6') including, for example, a heating wire for electric heating, a thermocouple, and a temperature control device, so that the products of each reaction zone can be heated to a temperature suitable for proceeding with a dry reforming reaction in the next reaction zone. At this time, the heating wire may be installed to wrap around all or part of each reaction zone connecting part, and the size of the area wrapped by the heating wire may be appropriately adjusted according to the size of each reaction zone connecting part, the flow rate of the internal fluid, the temperature difference between each reaction zone, etc.

[0080] Meanwhile, the reactant supply unit (2) may also be equipped with a temperature control unit that performs the same function.

[0081] Additionally, a CO2 additional input unit (11) can be connected to a reactant supply unit and a reaction zone connection unit at the front, middle, or rear end of each temperature control unit. Through each CO2 additional input unit (11), if the amount of CO2 required in each reaction zone is insufficient, CO2 can be optionally supplied together with inert gases such as Ar, He, and N2. It is preferable to connect the CO2 additional input unit (11) to the rear end of each temperature control unit (6') so that the internal gases can be preheated to a temperature suitable for each reaction zone before being supplied to each reaction zone.

[0082] In addition, for descriptions of common components and functions such as catalysts filled in each reaction zone, temperature settings and preheating of each reaction zone, etc., you can refer to the section explained in relation to Fig. 3.

[0084] Hereinafter, preferred experimental examples are presented to aid in understanding the present invention. However, these experimental examples are intended to explain the present invention more specifically, and the scope of the present invention is not limited by them. It will be obvious to those skilled in the art that various changes and modifications are possible within the scope and technical spirit of the present invention.

[0086] Experimental example

[0087] Experimental Example 1. Paraffinic (C) through an integrated multi-stage reaction system n H 2n+2 ), naphthenic (C n H 2n ), olefin-based (C n H 2n ), diolefin series (C n H 2n-2 ), acetylene-based (C n H 2n-2 C including all of ) etc. 1 -C 6 Dry reforming of carbon-containing hydrocarbons

[0088] To dry reform a gas containing a mixture of C1-C6 hydrocarbons, a porous quartz filter was installed in the center of a cylindrical quartz reactor (one for each reaction zone, totaling six) with a diameter of 20 mm and a length of 400 mm, isolated from the outside air, to stably support the catalyst layer, and 0.1 g of powdered Ni(10 wt%) / Al2O3 catalyst was placed on the filter. The catalyst was prepared by highly dispersing and supporting Nickel(II) nitrate hexahydrate as a precursor on an Al2O3 support using an initial wet impregnation method, and was used after calcining at 500°C for 4 hours in an oxygen atmosphere to remove functional groups contained in the precursor.

[0089] Inside the reactor, argon gas at room temperature at 100 cm3 After removing impurities by flowing at a rate of / min for more than 30 minutes, the temperature was raised to the target temperature in an argon atmosphere. The first reaction zone was raised to 450℃, the second to 550℃, the third to 650℃, the fourth to 750℃, the fifth to 850℃, and the sixth to 950℃ at a rate of 10℃ / min. After reaching the target temperature, the reactants were supplied to start the dry reforming reaction.

[0090] 100 cm of hydrocarbons mixed with equal amounts of C1-C6 alkanes 3 It was fed into the reactor at a flow rate of / min, at a volume ratio of 6 times the volume of C6 alkane hydrocarbon (hexane) (i.e., the CO2 flow rate is 100cm³ 3 Mix carbon dioxide gas at a rate of 1 / min to a total of 200 cm 3 A mixed gas of / min was initially introduced into the first reaction zone.

[0091] Using a gas chromatography system equipped with flame ionization detectors and thermal conductivity detectors installed between each reaction zone, the composition of the gas emitted after the reaction in each zone was monitored in real time. Based on the composition of the exhaust gas from each zone, the optimal CO2 concentration required for the reaction in the subsequent zone was calculated, and the CO2 consumed in the preceding reactor was calculated. Consequently, the necessary amount of CO2 was additionally injected into each reaction zone to continue the reaction. For example, analysis of the exhaust gas in Zone A of Fig. 3 using a gas analyzer showed that the CO2, which was initially mixed at a volume ratio of 6 times that of the C6 alkane hydrocarbon, was approximately 90% (90 cm²) of the initial input amount. 3 / min) reacts with C6, and about 10% (10cm²) 3 It was confirmed that ( / min) is discharged in an unreacted state. Therefore, the gas composition ratio was recalculated before being injected into Zone B of Fig. 3, and the CO2 flow rate is the injected C5 volume (approx. 16.7 cm³) 3 5 times (83.33cm) of / min 3 So that it becomes / min), 73.33cm3 An additional amount of / min was added. Subsequently, compositional analysis was performed on the flow passing through reaction zones B, C, D, and E in the same manner, and the ratio of CO2 was optimized for subsequent input into the reactor.

[0092] After the reaction is finally completed, stop the flow of the reactant gas and introduce argon gas at a rate of 100 cm 3 The reactor was cooled to room temperature while being fed at a rate of / min.

[0094] Experimental Example 2. Paraffinic (C) through an integrated multistage catalytic reaction system including six reaction zones with different residence times n H 2n+2 ), naphthenic (C n H 2n ), olefin-based (C n H 2n ), diolefin series (C n H 2n-2 ), acetylene-based (C n H 2n-2 C including all of ) etc. 1 -C 6 Dry reforming of carbon-containing hydrocarbons

[0095] The inner diameter of the first reaction zone was 60 mm, the inner diameter of the second reaction zone was 40 mm, the inner diameter of the third reaction zone was 30 mm, the inner diameter of the fourth reaction zone was 20 mm, the inner diameter of the fifth reaction zone was 10 mm, and the inner diameter of the sixth reaction zone was 5 mm, with different residence times in each reaction zone. Dry modification was performed in the same manner as in Experimental Example 1 above, except for the reactor specifications above.

[0097] Comparative Experimental Example 1. C through a conventional single reaction system 1 -C 6 Dry reforming of mixed hydrocarbons

[0098] A mixture of C1-C6 alkane hydrocarbons was dry-reformed using a commonly used single-catalyst reaction system.

[0099] Before being fed into the catalytic reactor, the hydrocarbon mixture containing C1-C6 alkanes was separated into C1, C2, C3, C4, C5, and C6 alkanes, respectively, using differences in boiling points.

[0100] Each reaction gas of the C1-C6 alkanes was fed into different catalytic reactors set with reaction conditions suitable for each reactant, following a separate path.

[0101] Each catalyst reactor was of the same type as the catalyst reactors installed in each reaction zone used in Experimental Example 1. That is, 0.1 g of powdered Ni(10 wt%) / Al2O3 catalyst, identical to that used in Experimental Example 1, was placed on a filter installed in the center of a cylindrical quartz reactor with a diameter of 20 mm and a length of 400 mm, and the reaction was carried out.

[0102] The catalytic reaction was carried out at temperatures of each reactor: 950°C for the methane reforming reactor, 800°C for the ethane reforming reactor, 750°C for the propane reforming reactor, 650°C for the butane reforming reactor, 550°C for the pentane reforming reactor, and 450°C for the hexane reforming reactor. The reactant composition of each reactor was maintained according to the ratio of hydrocarbon to carbon dioxide as presented in Reaction Scheme 1 above (i.e., hydrocarbon to carbon dioxide = 1:1 volume ratio for C1, hydrocarbon to carbon dioxide = 1:2 volume ratio for C2, hydrocarbon to carbon dioxide = 1:3 volume ratio for C3, hydrocarbon to carbon dioxide = 1:4 volume ratio for C4, hydrocarbon to carbon dioxide = 1:5 volume ratio for C5, and hydrocarbon to carbon dioxide = 1:6 volume ratio for C6, and the reactants were introduced into the reactors and reacted, and the total flow rate of the reactants in each reactor was maintained at 100 cm3 / min.

[0103] The gas emitted after the reaction was monitored in real time using a gas chromatography system equipped with a flame ionization detector and a thermal conductivity detector. After the reaction was completed, 100 cm of argon gas was introduced into each reactor.3 It was cooled to room temperature by supplying at a rate of / min.

[0105] Evaluation of experimental results

[0106] The results of the dry reforming reaction of C1-C6 mixed hydrocarbons carried out according to the comparative experimental example and experimental example 1 of the present invention will be explained with reference to FIGS. 1 and FIGS. 5.

[0107] As shown in Fig. 5, when the dry reforming reaction was carried out using the multi-stage catalytic reaction system according to Experimental Example 1, the residue of C1 to C6 hydrocarbons in the final product was small and most of it was converted to H2 / CO, so it can be confirmed that the H2 / CO conversion rate and yield were superior compared to the dry reforming system carried out using the single catalytic reaction system according to Comparative Experimental Example 1 shown in Fig. 1.

[0108] Specifically, referring to FIG. 5, the temperature of each reaction zone of the multi-stage catalytic reaction system shown in FIG. 3 was set to a temperature suitable for the decomposition reaction of hydrocarbons corresponding to their respective chain lengths and connected in series so that the dry reforming reaction could occur sequentially as hydrocarbons having each carbon number were decomposed into hydrocarbons having a smaller carbon number. For example, in the first reaction zone set to a temperature suitable for the decomposition and dry reforming reaction of C6, the reaction product containing residual hydrocarbons is decomposed to C5 or lower and fed into the second reaction zone; in the second reaction zone set to a temperature suitable for the decomposition and dry reforming reaction of C5, the hydrocarbons are decomposed to C4 or lower and residual hydrocarbons are fed into the third reaction zone; and after this process is repeated in the third to fifth reaction zones, finally in the sixth reaction zone, the C1 hydrocarbons generated or unreacted in the preceding reaction zones undergo a catalytic reaction and are converted into the final product H2 / CO, so almost no unreacted hydrocarbons remain, and it can be seen that the final conversion rate and yield are very high.

[0109] On the other hand, in the case of Comparative Experimental Example 1, the dry reforming reaction in each reactor was not completely finished, and the reaction proceeded only to the point where many hydrocarbons were decomposed into hydrocarbons with a small number of carbon atoms, and it can be seen that hydrocarbons still remain. Referring to Fig. 1, the conventional single-catalyst reaction system according to Comparative Experimental Example 1 is inefficient compared to the present invention because it requires a separate pretreatment step in which hydrocarbons separated according to the number of carbon atoms through a separation process are fed into each reactor. Furthermore, since the separated hydrocarbons are not completely converted into a mixture of H2 and CO, and are decomposed into a mixture of hydrocarbons with a smaller number of carbon atoms than the feed gas, and the hydrocarbon mixture that was not reformed into a final synthesis gas state remains as a residue, it can be seen that the final conversion rate and yield are very low compared to the example.

[0110] In addition, although not shown in Fig. 1, in conventional reaction systems, a multi-step separation process is required to separate the gas mixture generated in each reactor to separate the H2 / CO product and unreacted hydrocarbons, which again results in significant equipment investment and operating costs. Explanation of the symbols

[0111] 1 : Mass flow measurement controller 2: Reactor supply unit 3 : Quartz reactor 4, 4' : Heating element 5, 5' : Heat group 6, 6' : Temperature controller 7 : Gas analyzer 8: Gas reaction section 9: Generated gas discharge section 10: Catalyst layer 11: Additional CO2 input section 12-1 ~ 12-5 : Reaction zone connection A: First reaction zone B: Second reaction zone C: Third reaction zone D: 4th reaction zone E: 5th reaction zone F: 6th reaction zone

Claims

Claim 1 A reactant supply unit for supplying reactants including hydrocarbons and carbon dioxide; a gas reaction unit in which a plurality of reaction zones are connected in series to react the reactants on the catalyst, with the reaction unit filled with a catalyst for a dry reforming reaction; and a product gas discharge unit for discharging gas generated by passing through the gas reaction unit; wherein the hydrocarbon may include a substituent, and the hydrocarbon is a paraffinic (C) having n of 1 to 6. n H 2n+2 ) hydrocarbons, naphthenic types (C) where n is 3 to 6 n H 2n ) hydrocarbons, olefins having n of 2 to 6 (C n H 2n ) hydrocarbons, diolefins in which n is 3 to 6 (C n H 2n-2 ) hydrocarbons and acetylene-based (C) having n of 2 to 6 n H 2n-2 A multi-stage catalytic reaction system for the simultaneous conversion of hydrocarbons having various carbon numbers, characterized in that two or more mixtures selected from a group consisting of hydrocarbons or any one where n is 2 to 6 are supplied, the gas reaction section is divided into a number of reaction zones corresponding to the maximum number of carbons (n) of the hydrocarbons included in the reactants, and the reaction zones have a higher temperature in the subsequent reaction zone than in the preceding reaction zone. Claim 2 A multi-stage catalytic reaction system for the simultaneous conversion of hydrocarbons having various carbon numbers, wherein, in claim 1, the plurality of reaction zones are characterized in that the outlet of the front reaction zone is directly connected to the inlet of the rear reaction zone, or the outlet of the front reaction zone is connected to the inlet of the rear reaction zone by a reaction zone connecting part. Claim 3 A multi-stage catalytic reaction system for the simultaneous conversion of hydrocarbons having various carbon numbers, characterized in that, in paragraph 2, at least one of the plurality of reaction zones is connected to a CO2 additional input section in which CO2 and / or inert gas can be introduced. Claim 4 A multi-stage catalytic reaction system for the simultaneous conversion of hydrocarbons having various carbon numbers, characterized in that, in paragraph 2, at least one of the reaction zone connection parts is equipped with a temperature control unit, and a CO2 additional input part capable of introducing CO2 and / or inert gas is connected upstream of the temperature control unit installation location. Claim 5 delete Claim 6 A multi-stage catalytic reaction system for the simultaneous conversion of hydrocarbons having various carbon numbers, wherein, in claim 1, the reactants are mixed in a ratio of 1:1 to 10:1 based on the total number of carbon atoms of each carbon. Claim 7 ◈Claim 7 was abandoned upon payment of the registration fee.◈ A multi-stage catalytic reaction system for the simultaneous conversion of hydrocarbons having various carbon numbers, characterized in that, in Claim 6, the carbon dioxide is introduced together with the hydrocarbon or is introduced from a separate source. Claim 8 delete Claim 9 ◈Claim 9 was abandoned upon payment of the registration fee.◈ A multi-stage catalytic reaction system for the simultaneous conversion of hydrocarbons having various carbon numbers, characterized in that, in Claim 1, the temperature of the gas reaction section is 25 to 1500℃. Claim 10 ◈Claim 10 was abandoned upon payment of the registration fee.◈ A multi-stage catalytic reaction system for the simultaneous conversion of hydrocarbons having various carbon numbers, wherein the gas reaction unit is characterized by a gradual increase in temperature for each reaction zone in claim 1. Claim 11 A multi-stage catalytic reaction system for the simultaneous conversion of hydrocarbons having various carbon numbers, wherein, in claim 1, the gas reaction unit sets the pressure differently for each reaction zone. Claim 12 A multi-stage catalytic reaction system for the simultaneous conversion of hydrocarbons having various carbon numbers, wherein, in claim 1, the gas reaction unit is characterized by the inner diameter of the reactor gradually increasing or decreasing or changing inconsistently for each reaction zone. Claim 13 A multi-stage catalytic reaction system for the simultaneous conversion of hydrocarbons having various carbon numbers, wherein the catalyst is used in the form of a single-composition catalyst composed of any one selected from the group consisting of nickel (Ni), lanthanum (La), gold (Au), cerium (Ce), ruthenium (Ru), rhodium (Rh), palladium (Pd), cobalt (Co), iron (Fe), iridium (Ir), chromium (Cr), gallium (Ga), tungsten (W), rhenium (Re), niobium (Nb), molybdenum (Mo), magnesium (Mg), manganese (Mn), copper (Cu), titanium (Ti), lithium (Li), yttrium (Y), ytterbium (Yb), boron (B), barium (Ba), silver (Ag), and platinum (Pt), or an alloy or intermetallic compound containing two or more components. Claim 14 A multi-stage catalytic reaction system for the simultaneous conversion of hydrocarbons having various carbon numbers, wherein, in claim 13, the catalyst is supported on one or more supports selected from the group consisting of alumina (Al2O3), silica (SiO2), titania (TiO2), zirconia (ZrO2), ceria (CeO2), magnesia (MgO), lanthanum (La2O3), barium (BaO), silicon carbide (SiC), carbon black, activated carbon, graphene oxide, graphite, metal-organic frameworks (MOFs), zeolites, hydroxyapatite (HAP), MCM-41, SBA-15, and carbon nanotubes. Claim 15 A multi-stage catalytic reaction system for the simultaneous conversion of hydrocarbons having various carbon numbers, characterized in that, in claim 1, the catalyst is a mixture of one or more of a metal catalyst supported on or not supported on a support, or a support not supported with a catalyst component.

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