JP2014080328A - Joint production method of synthetic gas and hydrogen not discharging co2 from process - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a joint production method of synthetic gas and hydrogen,not discharging COfrom a process.SOLUTION: The joint production method of synthetic gas and hydrogen comprises: a reforming step in which synthetic gas is generated by reforming a light hydrocarbon gas in which a carbon dioxide/carbon mole ratio is adjusted without adding carbon dioxide from an outside, at a steam/carbon mole ratio of 1.7 or less under the presence of a reforming catalyst in which ruthenium and/or rhodium is carried in an amount 200-2,000 wtppm of a metal conversion value in a magnesium oxide carrier having a specific surface area of 0.1-5.0 m/g; a shift step in which steam is added to a part of the obtained synthetic gas to perform water-gas-shift reaction; and a hydrogen separation step in which gas obtained in the shift step is refined to take out high purity hydrogen gas. In the joint production method, residual gas that remains after taking out high purity hydrogen gas in the hydrogen separation step is recycled into an upstream side of the reforming step.

Description

The present invention relates to a method of co-producing syngas and hydrogen by reforming light hydrocarbon gas such as natural gas without discharging CO ₂ from the process side to the environment.

Synthesis gas mainly composed of hydrogen (H ₂ ) and carbon monoxide (CO) is a raw material for liquid fuel oils such as GTL (Gas to Liquids) and DME (dimethyl ether), and chemical products such as ammonia, methanol, and acetic acid. As widely used. A light hydrocarbon gas such as natural gas can be used as a raw material for the synthesis gas, and steam or carbon dioxide gas is added to the raw material gas in the presence of a catalyst, and heat necessary for the reaction is supplied. A synthesis gas having an H ₂ / CO molar ratio of about 0.5 to 3 can be efficiently produced.

For example, when the raw material gas is methane, synthesis gas having a H ₂ / CO molar ratio of 3 can be produced through the steam reforming reaction shown in the following formula 1 by adding steam. Further, by adding carbon dioxide (CO ₂ ), a synthesis gas having a H ₂ / CO molar ratio of 1 can be produced through a CO ₂ reforming reaction represented by the following formula 2.
[Formula 1]
_{CH 4 + H 2 O = CO} + 3H 2
[Formula 2]
_{CH 4 + CO 2 = 2CO +} 2H 2

  Since these reforming reactions of Formula 1 and Formula 2 are both endothermic reactions, conventionally, the reactor (reformer) includes a catalyst tube in the heating furnace in addition to ATR (Auto Thermal Reforming) and POX (Partial Oxidation). And a tubular reformer that heats the catalyst tube with the radiant heat of the combustion gas has been used (Patent Document 1). In particular, the tubular reformer can be used to efficiently produce synthesis gas even when the production amount of synthesis gas is relatively small, and is therefore used in many synthesis gas production plants.

JP 2006-056766 A

In recent years, design in consideration of the global environment has been demanded in all directions, and a technology that does not emit greenhouse gases typified by carbon dioxide is also demanded in a synthesis gas production factory. However, in the process of generating synthesis gas, to accompany water gas shift reaction of the formula 3 in addition to the reforming reactions of equations 1 and 2 above, CO ₂ is generated by this, the removal of CO ₂ from the synthesis gas It may be discharged to the environment through a decarboxylation process or discharged to the environment in the manufacturing process of downstream chemical products.
[Formula 3]
_{CO + H 2 O = CO 2} + H 2

In addition, as represented by power generation using fuel cells and hydrogen turbine combined cycles, the development and commercialization of technology that uses hydrogen as a fuel that does not generate CO ₂ has progressed, and an era in which the demand for hydrogen has dramatically increased has arrived. It's getting on.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a method for co-producing syngas and hydrogen that does not discharge CO ₂ from the process side to the environment. In particular, an object is to provide a method for co-production of a synthesis gas having a H ₂ / CO molar ratio of about ₂ suitable for a raw material composition such as GTL and high-purity hydrogen without discharging CO ₂ from the process side to the environment. It is said.

In order to achieve the above object, the method for co-production of synthesis gas and hydrogen provided by the present invention uses a light hydrocarbon gas whose carbon dioxide / carbon molar ratio is adjusted without adding carbon dioxide from the outside, and has a specific surface area of 0.1. Synthesized by reforming at a steam / carbon molar ratio of 1.7 or less in the presence of a reforming catalyst in which ruthenium and / or rhodium is supported in a metal conversion value of 200 to 2000 wtppm on a magnesium oxide support of 1 to 5.0 m ² / g. A reforming step for generating gas, a shift step for adding a steam to a part of the obtained synthesis gas to perform a water gas shift reaction, and purifying the gas obtained in the shift step to extract high-purity hydrogen gas A syngas and hydrogen co-production method comprising a hydrogen separation step, wherein residual gas remaining after high-purity hydrogen gas is taken out in the hydrogen separation step is recycled upstream of the reforming step. It is characterized by a door.

According to the present invention, synthesis gas having a H ₂ / CO molar ratio of about ₂ suitable as a raw material such as GTL from light hydrocarbon gas such as natural gas without discharging CO ₂ as a greenhouse gas from the process side to the environment. And hydrogen can be co-produced.

It is a process flowchart which shows one specific example of the co-production method of the synthesis gas and hydrogen of this invention. FIG. 5 is a process flow diagram illustrating a method for producing synthesis gas and hydrogen in Comparative Example 1. It is a process flowchart which shows the other specific example of the co-production method of the synthesis gas and hydrogen of this invention.

Hereinafter, a specific example of the method for co-producing syngas and hydrogen according to the present invention will be described with reference to the process flow diagram of FIG. In the method of co-production of synthesis gas and hydrogen shown in FIG. 1, a light hydrocarbon gas whose carbon dioxide / carbon molar ratio is adjusted without adding carbon dioxide from the outside is used, and a specific surface area of 0.1 to 5.0 m ² / A reforming step of generating synthesis gas by reforming at a steam / carbon molar ratio of 1.7 or less in the presence of a reforming catalyst in which ruthenium and / or rhodium is supported on a magnesium oxide support of g in a metal conversion value of 200 to 2000 wtppm. A shift step in which steam is added to a part of the resultant synthesis gas to perform a water gas shift reaction, a hydrogen separation step in which the gas obtained in the shift step is purified to extract high-purity hydrogen gas, and the aqueous And a decarbonation step of decarbonating the remaining synthesis gas excluding the part of the synthesis gas in which the gas shift reaction is performed. The carbon dioxide gas removed in the decarbonation step and the residual gas remaining after the high-purity hydrogen gas is taken out in the hydrogen separation step are recycled upstream of the reforming step.

  More specifically, each process will be described. First, a light hydrocarbon gas (stream number S1) as a raw material gas is sent to the first heating means 1 such as a heat exchanger, where the downstream gas is heated by a heating medium such as low-pressure steam. Heat to the temperature required for the hydrodesulfurization process. An amount of hydrogen gas (stream number S2) required for the hydrodesulfurization step is added to the heated light hydrocarbon gas, and then introduced into the hydrodesulfurization apparatus 2. The hydrogen gas added here is partly extracted from the high-purity product hydrogen gas obtained by the hydrogen separator 15 described later.

  The hydrodesulfurization apparatus 2 has a reactor filled with, for example, a Co—Mo based catalyst or a Ni—Mo based catalyst in order to remove a sulfur component that becomes a catalyst poison of the reforming catalyst. By introducing the raw material gas to which hydrogen is added, the sulfur compound contained in the raw material gas is reacted with hydrogen to be converted into hydrogen sulfide and removed from the raw material gas. Removal of hydrogen sulfide can be easily performed by adsorption using ZnO or a chemical absorption method using an alkanolamine solution.

Next, a process steam (stream number S3) in a saturated state at a pressure of about 0.8 to 3.3 MPaG for steam reforming is added to the raw material gas hydrodesulfurized in the hydrodesulfurization apparatus 2, and Recycled CO ₂ gas (stream number S4) containing CO ₂ for CO ₂ reforming is added. The recycled CO ₂ gas is composed of carbon dioxide gas removed by the decarbonation device 9 described later and residual gas remaining after the high-purity hydrogen gas is taken out by the hydrogen separation device 15.

When the above process steam is added, the hydrocarbon / gas mole ratio of the mixed gas composed of the raw gas after hydrodesulfurization, the recycled CO ₂ gas and the process steam (that is, the number of moles of H ₂ O is included in the hydrocarbon). The raw material after the above hydrodesulfurization so that the value divided by the total number of moles of carbon atoms, also referred to as S / C molar ratio, is 1.7 or less, preferably 0.7 or more and 1.7 or less. Adjust the amount added to the gas. If this value is less than 0.7, the carbon activity at the outlet condition of the reforming process exceeds 1, and thus carbon tends to be deposited on the reforming catalyst. On the other hand, when this value exceeds 1.7, the duty of the reformer increases, which is not preferable.

The carbon activity is a value that serves as an index for determining the presence or absence of carbon deposition, and can be obtained from the ratio of the partial pressure of the product gas at a certain temperature and pressure and the equilibrium constant of the carbon production reaction. For example, regarding the carbon deposition reaction (Boundary reaction) from carbon monoxide represented by the following formula 4, the carbon activity (Ac) is calculated by the following formula 5 from the ratio of the partial pressure of carbon dioxide and carbon monoxide and the equilibrium constant of this reaction. Can be requested. In Equation 5 below, K is the equilibrium constant of the Boundouard reaction, and Pco and Pco ₂ are the partial pressures of CO and CO ₂ under the operating conditions, respectively.
[Formula 4]
2CO = C + CO ₂
[Formula 5]
Ac = K · ((Pco) ² / Pco ₂ )

On the other hand, when the recycled CO ₂ gas is added, the carbon dioxide / carbon molar ratio (that is, the number of moles of CO ₂ is carbonized) of the mixed gas composed of the raw gas after hydrodesulfurization, the recycled CO ₂ gas, and process steam. The amount added to the raw material gas after the hydrodesulfurization is adjusted so that the value obtained by dividing by the total number of moles of carbon atoms contained in hydrogen is 0.1 to 3.0. If this value is less than 0.1, the H ₂ / CO molar ratio of the synthesis gas obtained in the reforming step will be high. On the other hand, when this value exceeds 3.0, the load of the third compressor 16 for recycling the recycled CO ₂ gas is remarkably increased.

  As described above, the mixed gas in which the S / C molar ratio and the carbon dioxide / carbon molar ratio are adjusted is then sent to the second heating means 3 such as a heat exchanger, where 500 ° C. is applied by a heating medium such as high-pressure steam. After heating to the extent, it is introduced into the reformer 4 as a reformer inlet gas (stream number S5). The reformer 4 is constituted by, for example, a tubular reformer. A tubular reformer is an apparatus for reforming a process side fluid by supplying reaction heat from outside the reaction tube while flowing the process side fluid into one or a plurality of reaction tubes filled with a reforming catalyst. It is.

  In the reformer 4, it is preferable to control the outlet temperature on the process side to be 800 to 950 ° C. and the outlet pressure to be 0.15 to 3.0 MPaG, thereby allowing the reforming reaction to proceed efficiently. . If the outlet temperature is less than 800 ° C, the conversion rate of methane decreases, while if it exceeds 950 ° C, it exceeds the design temperature of the existing tube. When the outlet pressure is less than 0.15 MPaG, it is impossible to pass downstream equipment. On the other hand, when the outlet pressure exceeds 3.0 MPaG, the conversion rate of methane decreases.

As the reforming catalyst filled in the reaction tube of the reformer 4, a magnesium oxide support having ruthenium and / or rhodium supported in a metal equivalent value of 200 to 2000 wtppm is used. This is because, as described above, the recycled CO ₂ gas containing carbon dioxide is recycled upstream of the reformer 4, so that the process side of the reformer 4 is in a condition where carbon is likely to precipitate due to side reactions. In the conventional Ni-based steam reforming catalyst, carbon is deposited and the catalyst is easily deactivated.

  On the other hand, by using a reforming catalyst in which a predetermined amount of ruthenium and / or rhodium is supported on the above-described magnesium oxide support, carbon deposition is maintained while maintaining high synthesis gasification activity for light hydrocarbon gas. The activity can be remarkably suppressed. If the amount of ruthenium and / or rhodium to be supported is less than 200 wtppm, sufficient catalytic activity is difficult to obtain. On the other hand, when this value exceeds 2000 wtppm, carbon tends to precipitate on the catalyst surface.

The specific surface area of the magnesium oxide carrier measured based on the BET method is 0.1 to 5.0 m ² / g. In this case, the shape of the magnesium oxide support is preferably a ring shape, a multi-hole shape, or a tablet shape. By using such a carrier, it is possible to carry out a catalytic reaction satisfactorily in a state of being filled in a reaction tube having an inner diameter of about 15 to 150 mm. If the specific surface area is less than 0.1 m ² / g, sufficient catalytic activity cannot be obtained. On the other hand, if this value exceeds 5.0 m ² / g, carbon tends to be deposited on the catalyst surface.

As a method for preparing the reforming catalyst, a magnesium oxide carrier molded body can be produced by, for example, tableting molding by sufficiently mixing magnesium oxide and a molding aid such as graphite. The molded body made of magnesium oxide preferably has a purity of 98% by mass or more, and more preferably 99% by mass or more. In particular, it is not preferable to mix a component that enhances the carbon deposition activity or a component that decomposes in a high-temperature reducing gas atmosphere, for example, a metal such as iron or nickel, or an impurity such as silicon dioxide (SiO ₂ ). These impurities are preferably 1% by mass or less, more preferably 0.1% by mass or less, in the magnesium oxide molded body.

  As a method for supporting the catalyst on the obtained magnesium oxide support, a general method such as an impregnation method can be used. For example, in the case of the impregnation method, a metal salt of ruthenium and / or rhodium or an aqueous solution thereof as a catalyst is added to and mixed with a carrier dispersed in water, and then the carrier is separated from the aqueous solution, dried and calcined. .

  Alternatively, after exhausting the carrier, a method of adding a metal salt solution of about the pore volume to make the surface of the carrier evenly wet, drying and firing (incipient wetness method), or a mist-like metal salt A method of spraying the solution onto the carrier (Spray method) may be used. In these methods, water-soluble salts such as inorganic acid salts such as nitrates and chlorides and organic acid salts such as acetates and oxalates can be used as the catalyst metal salts. Alternatively, a metal acetylacetonate salt or the like may be dissolved in an organic solvent such as acetone and impregnated in a carrier.

  When impregnated with the water-soluble salt, the drying temperature is preferably 100 to 200 ° C, more preferably 100 to 150 ° C. On the other hand, when impregnated with an organic solvent, drying is preferably performed at a temperature 50 to 100 ° C. higher than the boiling point of the solvent. The firing temperature and firing time after drying are appropriately selected according to the specific surface area of the obtained carrier, but it is generally preferred to fire at 500 to 1100 ° C. for about 3 to 5 hours.

In the case of a tubular reformer, the reforming catalyst thus obtained is charged into the reaction tube so that the gas space velocity is, for example, 250 to 6000 hr ⁻¹ . The inner diameter, length, etc. of the reaction tube filled with the catalyst are determined in consideration of the aforementioned process side outlet temperature of 800 to 950 ° C. and outlet pressure of 0.15 to 3.0 MPaG.

  Returning to FIG. 1 again, the reformer outlet gas (stream number S6) discharged from the process side of the reformer 4 is sent to the first cooling means 5 such as a heat exchanger, where cooling water or the like is sent. It cools to the temperature suitable for the high temperature shift reaction mentioned later with a cooling medium. The product gas cooled by the first cooling means 5 is branched into two, and each is processed in a decarboxylation step and a water gas shift step.

  First, the treatment on the decarboxylation step side will be described. One of the two branched product gases is further cooled to a temperature of about 40 ° C. suitable for the subsequent decarboxylation step by the second cooling means 6 such as a heat exchanger. After the condensed water (stream number S12) generated by this cooling is removed in the first gas-liquid separation tank 7, the pressure is increased by the first compressor 8 to a pressure required for the treatment in the subsequent decarboxylation step. Send to 9.

  In the decarboxylation device 9, for example, carbon dioxide contained in the generated gas is removed using a general decarboxylation process such as a chemical absorption method or a physical absorption method. In the case of a chemical absorption method using an alkanolamine solution, the generated gas is supplied to the bottom of an absorption tower equipped with a shelf or a filler, and the regenerated chemical absorption liquid is supplied to the top. As a result, the product gas and the chemical absorption liquid are brought into countercurrent gas-liquid contact with each other in the tower, so that the carbon dioxide contained in the product gas is efficiently absorbed by the chemical absorption liquid. Thereby, the product synthesis gas (stream number S14) decarboxylated from the top of the absorption tower can be taken out.

This decarboxylated synthesis gas has an H ₂ / CO molar ratio adjusted to a predetermined ratio, and can be used as various raw materials. For example, when the H ₂ / CO molar ratio is about 2, it can be suitably used as a raw material for Fischer-Tropsch synthesis. Alternatively, when the H ₂ / CO molar ratio is about 1, it can be used as a raw material for direct synthesis of DME.

The chemical absorption liquid that has absorbed carbon dioxide is extracted from the bottom of the absorption tower and then sent to the regeneration tower. In the regeneration tower, the chemical absorbing solution is regenerated by stripping steam, and the dissociated carbon dioxide is discharged from the top of the regeneration tower. The carbon dioxide gas discharged from the regeneration tower and the residual gas generated in the hydrogen separator 15 to be described later are boosted to a predetermined pressure in the third compressor 16, and are reformed as the above-mentioned recycled CO ₂ gas (stream number S4). Recycle upstream.

Next, processing on the water gas shift process side will be described. Saturated process steam (stream number S7) having a pressure of about 0.8 to 3.3 MPaG for water gas shift reaction is added to the other of the two branched product gases. The high temperature shift reaction inlet gas (stream number S8) thus obtained is introduced into the high temperature shift reaction apparatus 10. The high-temperature shift reaction apparatus 10 includes a reactor filled with, for example, an iron-chromium-based or copper-chromium-based catalyst, and CO in the high-temperature shift reaction inlet gas is shifted to H ₂ by a high-temperature catalytic reaction.

After the gas processed in the high temperature shift reactor 10 is subsequently cooled to a temperature suitable for the low temperature shift reaction by the third cooling means 11, it is supplied to the low temperature shift reactor 12 as a low temperature shift reaction inlet gas (stream number S9). Introduce. The low temperature shift reactor 12 is composed of, for example, a reactor filled with a copper-zinc catalyst, and is shifted to H ₂ until the CO concentration in the product gas becomes lower due to the low temperature catalytic reaction.

  After the gas processed in the low temperature shift reactor 12 is sent to the fourth cooling means 13 to be cooled to a predetermined temperature, the condensed water (stream number S11) generated by this cooling is removed in the second gas-liquid separation tank 14 To the hydrogen separator 15. The hydrogen separation device 15 is constituted by, for example, a PSA (Pressure Swing Adsorption) device, and here, the PSA feed gas (stream number S10) from which condensed water has been removed is purified in the second gas-liquid separation tank 14. . In the hydrogen separator 15, high-purity hydrogen gas is taken out as product hydrogen (stream number S13), and residual gas after the high-purity hydrogen gas is taken out is discharged. This residual gas contains carbon dioxide and is recycled to the upstream side of the reforming step together with the carbon dioxide gas discharged from the decarbonator 9 described above.

As described above, in the method for co-producing syngas and hydrogen according to an embodiment of the present invention, all the carbon dioxide generated in the process is recovered and recycled to the upstream side of the reforming step. No CO ₂ is emitted from the process side to the environment as a result of co-production. Further, since carbon dioxide necessary for CO ₂ reforming in the reforming step can be covered by this recycled carbon dioxide, it is not necessary to add carbon dioxide from the outside.

  The method for co-production of synthesis gas and hydrogen according to the present invention has been described with a specific example. However, the present invention is not limited to such a specific example. For example, in the above-described method for co-production of synthesis gas and hydrogen according to one embodiment of the present invention, a part of the gas obtained in the reforming process is decarboxylated to produce a product synthesis gas containing almost no carbon dioxide However, if it is desirable that the product synthesis gas contains carbon dioxide gas, such as methanol raw material, part or all of the product gas from which condensed water has been removed in the first gas-liquid separation tank 7 is removed. The product synthesis gas can be used as it is without carbonation. FIG. 3 shows an example in which the entire product gas from which condensed water has been removed in the first gas-liquid separation tank 7 is used as the product synthesis gas without being treated by the decarboxylation device 9.

[Example 1]
Natural gas is used as a light hydrocarbon gas as a raw material gas, and H ₂ / CO is converted from natural gas adjusted to an S / C molar ratio of 1.30 along the process flow diagram not including the decarboxylation step shown in FIG. The process calculation was performed on the assumption that a synthesis gas of 17,600 Nm ³ / h having a molar ratio of 2.00 and a high-purity hydrogen gas of 10,000 Nm ³ / h were co-produced. In this process calculation, the outlet temperature on the process side of the reformer 4 was 900 ° C., the outlet pressure was 2000 kPaG, and the steam added to the raw material gas was saturated steam of 3300 kPaG. The flow rate and composition of each flow obtained by this process calculation are shown in Table 1 below.

From the results in Table 1 above, it was found that by adjusting the CO ₂ / C molar ratio to 0.64, synthesis gas and hydrogen can be produced together without discharging CO ₂ to the atmosphere. In addition, it turned out that the natural gas of 6,600 Nm < ³ > / h is needed as source gas. The consumption amount of process steam was 13.6 t / h, and the heat load of the reformer 4 was 25 MW.

[Comparative Example 1]
For comparison, the process calculation was performed on the assumption that almost the same amount of synthesis gas and hydrogen as in Example 1 were produced according to the process flow diagram of FIG. That is, the synthesis gas is a conventional CO ₂ recycle comprising the first heating means 1A, the hydrodesulfurization apparatus 2A, the second heating means 3A, the reforming apparatus 4A, the first cooling means 5A, and the first gas-liquid separation tank 7. It is assumed that hydrogen is generated in the forming step, and the hydrogen is first heating means 1B, hydrodesulfurization apparatus 2B, second heating means 3B, reforming apparatus 4B, first cooling means 5B, high temperature shift reaction apparatus 10, and third cooling means. 11, a low temperature shift reaction device 12, a fourth cooling means 13, a second gas-liquid separation tank 14, and a hydrogen separation device 15, and the conventional steam reforming process. The flow rate and composition of each flow obtained by this process calculation are shown in Table 2 below.

From the results in Table 2 above, the natural gas required to produce almost the same amount of synthesis gas and hydrogen as in Example 1 is 7,300 Nm ³ / h, which is about 10% more than in Example 1. I found out that In addition, it was necessary to add 2,500 Nm ³ / h of carbon dioxide from outside the system. The consumption amount of process steam was 15.4 t / h, and the heat load of the reformer was 27 MW, which was found to be about 13% and about 8% higher than Example 1, respectively.

[Example 2]
According to the process flow diagram shown in FIG. 1, assuming that the product synthesis gas having a H ₂ / CO molar ratio of 2.00 is decarboxylated and the resulting carbon dioxide is recycled upstream of the reforming process. Process calculations were performed. The S / C molar ratio and CO ₂ / C molar ratio of the reformer 4 inlet gas, and the outlet conditions were set to the same values as in Example 1 above. Although the production amount of high-purity hydrogen gas was 10,000 Nm ³ / h, the production amount of synthesis gas was gradually reduced. The flow rate and composition of each flow obtained by this process calculation are shown in Table 3 below.

From the results in Table 2 above, it was found that synthesis gas and hydrogen can be produced together without discharging CO ₂ to the atmosphere. The production amount of synthesis gas was 37,000 Nm ³ / h, and it was found that 12,200 Nm ³ / h natural gas was required as a raw material gas. Further, the consumption amount of process steam was 20.3 t / h, and the heat load of the reformer 4 was 44 MW.

[Comparative Example 2]
The process calculation was performed assuming that the same amount of synthesis gas and hydrogen as in Example 2 were produced using a Ni-based catalyst conventionally used as the reforming catalyst. In the case of a Ni-based catalyst, the S / C molar ratio was set to 3.00 so that carbon was not precipitated. The flow rate and composition of each flow obtained by this process calculation are shown in Table 4 below.

From the results of Table 4, the amount of raw material gas required to produce a synthesis gas and hydrogen approximately the same amount as in Example 2 is 10,300Nm ³ / h, 1,900Nm ³ as compared with Example 2 However, the consumption of process steam was 30.6 t / h, and the heat load of the reformer was 48 MW, which was found to be about 51% and about 9% higher than Example 2, respectively. Further, since the residual methane in the synthesis gas does not react in the downstream process, it can be used as a reformer fuel as an off-gas. In Comparative Example 2, the amount of residual methane is about 20% compared to Example 2. To compensate for this, the amount of natural gas used for reformer fuel will increase. As a result, the amount of natural gas used as the fuel for the reformer and utility boiler is increased by about 3,000 Nm ³ / h in Comparative Example 2 compared to Example 2, and as a result, the total amount of natural gas used is in Example 2. 1,100 Nm ³ / h.

DESCRIPTION OF SYMBOLS 1 1st heating means 2 Hydrodesulfurization apparatus 3 2nd heating means 4 Reforming apparatus 5 1st cooling means 6 2nd cooling means 7 1st gas-liquid separation tank 8 1st compressor 9 Decarbonation apparatus 10 High temperature shift reaction apparatus DESCRIPTION OF SYMBOLS 11 3rd cooling means 12 Low temperature shift reaction apparatus 13 4th cooling means 14 2nd gas-liquid separation tank 15 Hydrogen separation apparatus 16 2nd compressor 17 3rd compressor

Claims (5)

Light hydrocarbon gas with adjusted carbon dioxide / carbon molar ratio without adding carbon dioxide from outside, ruthenium and / or rhodium as metal conversion value on magnesium oxide support with specific surface area of 0.1-5.0 m ² / g In the presence of a reforming catalyst supported at 200 to 2000 wtppm at a steam / carbon molar ratio of 1.7 or less to generate synthesis gas, and steam is added to a portion of the resulting synthesis gas. A syngas and hydrogen co-production method comprising: a shift step for performing a water gas shift reaction; and a hydrogen separation step for purifying the gas obtained in the shift step and extracting high-purity hydrogen gas, the hydrogen separation step A method for co-producing syngas and hydrogen, wherein the residual gas remaining after taking out the high-purity hydrogen gas is recycled to the upstream side of the reforming step.   The method further includes a decarboxylation step of decarboxylating the remaining synthesis gas excluding the part, and the upstream side of the reforming step together with the residual gas generated in the hydrogen separation step of the carbon dioxide removed in the decarboxylation step The method for co-production of syngas and hydrogen according to claim 1, characterized in that it is recycled.   The method for co-producing syngas and hydrogen according to claim 1 or 2, wherein a PSA apparatus is used for taking out the high-purity hydrogen gas.   The method for co-producing syngas and hydrogen according to any one of claims 1 to 3, wherein the reforming step has an outlet temperature of 800 to 950 ° C and an outlet pressure of 0.15 to 3.0 MPaG. .   The method for co-producing syngas and hydrogen according to any one of claims 1 to 4, wherein the carbon dioxide / carbon molar ratio is adjusted to 0.1 to 3.0.

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