KR102053978B1 - High purity hydrogen production device and high purity hydrogen production method - Google Patents

Abstract

A dry reforming reaction unit for directly reacting methane and carbon dioxide in the biogas to produce a synthesis gas including hydrogen; And a gas conversion unit for generating carbon dioxide and hydrogen by reacting carbon monoxide in the synthesis gas generated through the dry reforming reaction unit with steam, and collecting the generated carbon dioxide. Provided is a hydrogen production apparatus comprising a.

Description

HIGH PURITY HYDROGEN PRODUCTION DEVICE AND HIGH PURITY HYDROGEN PRODUCTION METHOD}

The present invention relates to a novel high purity hydrogen production apparatus and a high purity hydrogen production method. More specifically, the present invention relates to a high purity hydrogen production apparatus and a high purity hydrogen production method using biogas.

Korea is an energy-poor country with a large amount of imports, and its energy consumption is among the top 10 in the world. The economy is heavily influenced by world oil prices. Therefore, it is urgent to develop and use renewable energy that can sustain growth for energy security. Korea is also the world's ninth-largest greenhouse gas emitter, with increasing pressure on reducing greenhouse gas emissions globally.

Therefore, hydrogen energy is emerging as a future clean energy that can simultaneously solve environmental problems such as global warming and energy dependence, and the method of producing hydrogen is using fossil fuels such as natural gas and sewage. There is a method of producing hydrogen from biomass such as sludge or food waste.

In economic terms, it is advantageous to use biomass to produce renewable energy such as biogas (including 55-70% methane and 30-45% carbon dioxide).

When various processes are used when using hydrogen from biogas, steam reforming is the most widely used.

However, the steam reforming method selectively removes and uses carbon dioxide contained in the biogas, which has a disadvantage in that it is greatly reduced in efficiency because energy is consumed. In order to compensate for this, the recent steam reforming method selectively removes carbon dioxide in biogas, and then, methane gas reacts with water vapor in a methane steam reforming reactor to produce hydrogen and carbon monoxide, followed by carbon monoxide by a catalyst in a water gas reactor. Is converted to carbon dioxide, and finally removes carbon monoxide in the synthesis gas in the selective conversion reactor, and finally to produce hydrogen by separating the carbon dioxide through a pressure swing adsorption process (PSA) (FIG. 1). This method has a problem in that the process is complicated and there are many additional facilities, which constrains the use of space and costs a lot in the separation process.

In addition, in the case of Patent Literature 1, hydrogen may be produced by reforming methane gas and steam. The apparatus is useful as a small hydrogen production apparatus for a polymer electrolyte fuel cell, but in a reforming using a large capacity or biogas, carbon dioxide must be selectively removed. In addition, since hydrogen production efficiency depends heavily on carbon dioxide removal efficiency, energy and cost associated with carbon dioxide removal are generated. In addition, this method has a problem that the process is complicated and there are a lot of facilities, there is a limitation of the space utilization and a lot of cost in the separation process.

Accordingly, there is a need for the development of a new hydrogen production apparatus capable of producing high purity hydrogen while minimizing carbon dioxide generation.

Korean Patent Application No. 10-2011-0033460 Republic of Korea Patent Registration No. 10-1629689

Embodiments of the present invention to provide a high purity hydrogen production apparatus and high purity hydrogen production method.

In one embodiment of the present invention, the dry reforming reaction unit for producing a synthesis gas containing hydrogen by directly reacting methane and carbon dioxide in the biogas; And a gas conversion unit for generating carbon dioxide and hydrogen by reacting carbon monoxide in the synthesis gas generated through the dry reforming reaction unit with water vapor, and collecting the generated carbon dioxide. Provided is a hydrogen production apparatus comprising a.

In an exemplary embodiment, the carbon dioxide collected in the gas conversion unit may be supplied to the dry reforming unit and recycled when reacted with methane in biogas.

In an exemplary embodiment, the gas conversion unit may include a hydrogen generating catalyst and an adsorbent for collecting carbon dioxide, and the hydrogen generating catalyst and an adsorbent for collecting carbon dioxide may be included in a weight ratio of 1: 9 to 9: 1.

In an exemplary embodiment, the hydrogen generating catalyst may include one or more transition metals selected from the group consisting of Cu, Ni, and Fe.

In an exemplary embodiment, the adsorbent for carbon dioxide capture may include an alkali metal double salt-based adsorbent or a hydrotalcite-based adsorbent.

In an exemplary embodiment, the alkali metal double salt-based adsorbent is an adsorbent prepared by co-precipitation or impregnation of alkaline earth metal carbonate, and the hydrotalcite-based adsorbent is represented by any one of the following [Formula 1] to [Formula 4] The adsorbent may be prepared by mixing a chloride and a carbonate represented by [Formula 5] by a hydrothermal synthesis process or a coprecipitation process.

[Formula 1]

(1-x) M (OH) ₂

[Formula 2]

(1-x) M (NO3) ₂

[Formula 3]

xL (OH) ₃

[Formula 4]

xL (NO3) ₃

[Formula 5]

(x / 2) A ₂ CO ₃

(In the formula 1 to 5, x has a value of 0.17 ~ 0.4, M is selected from the group consisting of magnesium (Mg), zinc (Zn) and nickel (Ni), L is aluminum (Al), gallium ( Ga), iron (Fe) and manganese (Mn), and A is selected from the group consisting of sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr). Can be chosen)

In an exemplary embodiment, the dry reforming reaction unit may include a catalyst including a compound represented by the following [Formula 6].

[Formula 6]

Sr _{1 - y} Y _y Ti _{1 - x} Ru _x O _{3 -δ}

(Where x is greater than 0 and less than 1. y is greater than 0 and less than 0.1. Δ is greater than 0 and less than 1).

In an exemplary embodiment, the catalyst including the compound represented by [Formula 6] may exhibit a methane conversion rate of 80% or more during the operation of 60 to 120 hours at a temperature of 700 ~ 900 ℃.

In an exemplary embodiment, the hydrogen production apparatus further includes a heat transfer unit for transferring the waste heat of the dry reforming reaction unit to the gas conversion unit, the heat transfer unit for generating a steam; And a preheating unit for preheating the synthesis gas generated in the dry reforming reaction unit.

In an exemplary embodiment, the preheating unit may be operated by the waste heat of the dry reforming reaction unit as a heat source.

In an exemplary embodiment, the hydrogen production apparatus may further include a hydrogen gas collecting unit connected to the gas conversion unit.

In another embodiment of the present invention, as a method for producing hydrogen through a hydrogen production apparatus including a dry reforming reaction unit and a gas conversion unit, in the dry reforming reaction unit, directly reacting methane and carbon dioxide in biogas to produce syngas. ; And in the gas conversion unit, reacting carbon monoxide in the synthesis gas generated through the dry reforming reaction unit with water vapor to generate carbon dioxide and hydrogen, and collecting the generated carbon dioxide; There is provided a hydrogen production method comprising a.

In an exemplary embodiment, the carbon dioxide collected according to the reaction of carbon monoxide and water vapor may be recycled upon reaction with methane in the biogas in a dry reforming reaction unit.

In an exemplary embodiment, the gas conversion unit may include a hydrogen generating catalyst and an adsorbent for collecting carbon dioxide, and the hydrogen generating catalyst and an adsorbent for collecting carbon dioxide may be included in a weight ratio of 1: 9 to 9: 1.

When using the hydrogen production apparatus according to an embodiment of the present invention can be easily recycled carbon dioxide. Accordingly, a separate process required to remove carbon dioxide is not required, so the efficiency of the process can be greatly improved compared to the existing process.

In addition, in the hydrogen production apparatus according to an embodiment of the present invention, the biogas is reacted by a dry reforming reaction, in which case the hydrogen generating ability may be further improved.

In addition, in the high purity hydrogen production apparatus of the present invention, since most of the carbon dioxide is removed, it is possible to produce high purity hydrogen. In addition, according to the hydrogen production apparatus and method of the present invention, carbon dioxide is hardly emitted and thus, hydrogen can be produced in an environmentally friendly manner.

Accordingly, the hydrogen production residual can be directly applied to a polymer electrolyte fuel cell (PEMFC), which is a low temperature fuel cell, and can be utilized in various industrial fields.

1 is a flow chart of a hydrogen production process according to the prior art.
2 is a flow chart of a hydrogen production process according to one embodiment of the invention.
Figure 3 is a block diagram showing a high purity hydrogen production apparatus according to an embodiment of the present invention.
Figure 4 is a photograph showing the dry reforming reaction unit of the high purity hydrogen production system according to an embodiment of the present invention (left) and the configuration diagram of the dry reforming reaction unit (right).
5 is a block diagram showing a water gas conversion unit of a high purity hydrogen production system according to an embodiment of the present invention.
6 is a graph illustrating dry reforming performance of the catalyst used in the dry reforming unit of the present invention.
7 is a graph illustrating the performance of the gas conversion unit (hydrogen generating catalyst and adsorbent for collecting carbon dioxide) used in one embodiment of the present invention.
8a and 8b are graphs showing the results of experiments on the performance of the gas conversion unit (hydrogen generating catalyst and carbon dioxide capture adsorbent) according to the present invention, respectively. In this case, all of the hydrotalcite-based adsorbents were used (FIG. 8A: ratio of the hydrogen generating catalyst and the adsorbent for carbon dioxide capture is 4: 1, FIG. 8B: the ratio of the hydrogen generating catalyst and the adsorbent for carbon dioxide capture is 1: 4. Occation).
Figure 9a is a graph showing the experimental results of the high-purity hydrogen production reactor according to the present invention, showing the results of the experiment by filling only the catalyst in the dry reforming reaction unit and the gas conversion unit, respectively.
Figure 9b is a graph showing the experimental results of the high-purity hydrogen production reactor according to the present invention, the dry reforming reaction unit with a catalyst, the gas conversion unit with the catalyst and the adsorbent together shows the results of the experiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Embodiments of the present invention have been described with reference to the accompanying drawings, which are described for purposes of illustration, whereby the technical idea of the present invention and its configuration and application are not limited.

Hydrogen Production Equipment

Hydrogen production apparatus according to the present invention comprises a dry reforming reaction unit for producing a synthesis gas containing hydrogen by direct reaction of methane and carbon dioxide in the biogas; And a gas conversion unit for generating carbon dioxide and hydrogen by reacting carbon monoxide in the synthesis gas generated through the dry reforming reaction unit with water vapor, and collecting the generated carbon dioxide. It includes. In the dry reforming unit of the hydrogen production apparatus of the present invention, the hydrogen production performance may be significantly improved compared to the existing apparatus by using a catalyst optimized for hydrogen generation. In addition, since the gas conversion unit of the hydrogen production apparatus directly captures carbon dioxide, the reaction performance of generating hydrogen in the gas conversion unit may be maintained without deterioration. Accordingly, hydrogen production performance can be greatly improved. This is described in detail below.

3 is a block diagram showing a high purity hydrogen production apparatus according to an embodiment of the present invention.

Referring to FIG. 3, the hydrogen production apparatus includes a dry reforming reaction part 100, a gas conversion part 200, and a heat transfer part 250.

The dry reforming reaction unit 100 is connected to a supply unit (not shown) to which biogas is supplied.

In the dry reforming reaction unit 100, a reaction represented by the following [Formula 1] is performed.

[Formula 1]

_{CH 4 + CO 2 ↔ 2CO +} 2H 2 (△ H 298K = +247 kJ mol -1)

In general, a hydrogen production apparatus using a reforming reaction uses a steam reforming reaction. Although the dry reforming reaction has a better efficiency, the dry reforming reaction does not find a suitable catalyst, and carbon is deposited to deteriorate the activity of the catalyst. This is because the durability of the hydrogen production apparatus is thereby deteriorated. However, in the present invention, a catalyst represented by the following [Formula 2], which has a very high methane conversion rate optimized for dry reforming reaction, is used. Accordingly, even if the dry reforming reaction is used, the performance of the catalyst is not deteriorated and the hydrogen gas (H ₂ ) is reduced. Can produce

In an exemplary embodiment, the dry reforming reaction unit 100 may include a perovskite catalyst. Specifically, the dry reforming reaction unit 100 may have excellent resistance to sulfur and carbon, and may easily control activity on dry reforming through doping. Perovskite catalyst can be used.

As the perovskite catalyst, a portion of strontium (Sr) is doped with yttrium (Y) and a portion of titanium (Ti) is doped with ruthenium (Ru) in the perovskite material represented by SrTiO ₃ . May be used. That is, as the catalyst, in the perovskite material having the structure of ABO ₃ , a part of A site (Sr) and a part of B site (Ti) are respectively different from each other (R at Y and B at A site). By doping substitution, a compound having a perovskite structure can be used.

For example, the perovskite catalyst may be a catalyst for biogas reforming including a compound represented by the following [Formula 2].

[Formula 2]

Sr _{1 - y} Y _y Ti _{1 - x} Ru _x O _{3 -δ}

(Where x is greater than 0 and less than 1. y is greater than 0 and less than 0.1. Δ is greater than 0 and less than 1).

In exemplary embodiments, substitution of the titanium site (B site of the perovskite structure), considering both the maintenance of a single phase of the catalyst, prevention of carbon deposition and / or catalyst poisoning, maintenance of the catalyst activity and improved electrical conductivity In the amount of ruthenium (Ru), that is, x may be greater than 0 and less than or equal to 1 (0 <x ≦ 1). In particular, it may be preferred if x is 0.05. In addition, the amount of yttrium (Y) substituted at the strontium site (A site in the perovskite structure), that is, y is greater than 0 and less than or equal to 0.08 (0 <y≤0.08), in particular, y is 0.08 It may be desirable.

Meanwhile, in an exemplary embodiment, partially doping and replacing the perovskite material with yttrium (Y) and ruthenium (Ru) may include yttrium (Y), strontium (Sr), titanium (Ti), and the like. Using distilled water or deionized water (DI water) as a solvent for dissolving the compound containing ruthenium (Ru), it can be carried out through the Pechini method (Pechini method) of the known dry catalyst preparation method.

In one embodiment, a catalyst prepared by dip coating the compound represented by [Formula 2] on a monolith support (that is, a catalyst including a compound represented by [Formula 2] supported on a monolith support) may be used.

In an exemplary embodiment, the biogas reforming catalyst may exhibit a methane conversion of at least 80% during 100 to 150 hours of operation at a temperature of 700 ~ 900 ℃.

On the other hand, the perovskite catalyst may be prepared in the form of a pallet (pallet) or powder, in this case, the reaction area with the biogas can be wider to increase the hydrogen production efficiency more.

On the other hand, as shown in Formula 1, the dry reforming reaction is an endothermic reaction, accordingly, the dry reforming reaction unit 100 should be maintained at an appropriate temperature (temperature of about 700 ~ 900 ℃).

In an exemplary embodiment, the hydrogen production apparatus may further include a preheater (not shown) between the supply unit and the dry reforming reaction unit 100, and in this case, between the supply unit and the dry reforming reaction unit 100. By preventing carbon deposits, dry reforming reactions can be carried out in large quantities.

Meanwhile, an example of the dry reforming reaction unit 100 is illustrated in FIG. 4. Inconel tube (Inconel tube) in Figure 4 is made of a large reforming reactor is used as a material for preventing carbon deposition of the reactor portion with increasing biogas flow rate. Insulation wool is used to maintain the temperature at which the catalyst is supported, with the catalyst preventing the catalyst powder from flying by the gas flow. Porous Inconel disks are designed to hold the catalyst in the reactor at a constant temperature range and to allow the gas to pass well after the reaction.

In addition, the hydrogen production apparatus connects the gas conversion unit 200 and the dry reforming reaction unit 100, and delivers carbon dioxide (CO ₂ ) supplied from the gas conversion unit 200 to the dry reforming reaction unit 100. It further includes a portion (not shown). That is, carbon dioxide can be recycled through the carbon dioxide delivery unit.

In general, the amount of carbon dioxide required for the dry reforming reaction is determined by the ratio of CO ₂ and CH ₄ , and quantitatively 1 is required as shown in Formula 1 above. However, in general, the ratio of carbon dioxide and methane contained in biogas is insufficient at a ratio of 2/3, and accordingly, carbon dioxide had to be separately supplied.

However, in the case of the present invention, carbon dioxide is generated and adsorbed in the gas conversion unit 200, and the carbon dioxide may be continuously supplied to the dry reforming reaction unit 100 by collecting the carbon dioxide. Accordingly, the dry reforming reaction may proceed without separately supplying carbon dioxide.

On the other hand, the synthesis gas containing hydrogen and carbon dioxide generated through the dry reforming reaction unit is transferred to the gas conversion unit 200 with heat.

In the gas conversion unit 200, a conversion reaction of a synthesis gas containing carbon monoxide and an adsorption reaction of carbon dioxide occur. The gas converting unit 200 includes a hydrogen generating catalyst for promoting the conversion reaction of the synthesis gas and includes an adsorbent for collecting carbon dioxide for adsorbing the carbon dioxide.

Syngas conversion reaction may be represented by the following [Formula 3].

[Formula 3]

CO + H ₂ O ↔ CO ₂ + H ₂ (△ H _298K = -41 kJ mol ^-1 )

The syngas conversion reaction is also called a water gas shift reaction, in which carbon monoxide and steam may react with the same molar number to produce hydrogen and carbon dioxide.

In an exemplary embodiment, a hydrogen generating catalyst may be used to carry out the syngas conversion reaction.

For example, the hydrogen generating catalyst may be prepared to include one or more transition metals selected from the group consisting of Cu, Ni, and Fe. In addition, the hydrogen generating catalyst may further contain ZnO and / or Al ₂ O ₃ as cocatalyst and support.

In one embodiment, the hydrogen production catalyst is CuO / ZnO / Al ₂ O ₃ And Cu / ZnO / Al ₂ O _{3 It} may be a catalyst comprising at least one selected from the group consisting of.

Meanwhile, the gas converting unit 200 includes an adsorbent for collecting carbon dioxide. Accordingly, carbon dioxide generated through a synthesis gas converting reaction may be adsorbed in the same reactor.

In an exemplary embodiment, the adsorbent for collecting carbon dioxide may include an alkali metal double salt based adsorbent or a hydrotalcite based adsorbent.

In one embodiment, the alkali metal double salt-based adsorbent is not limited as long as the alkaline earth metal carbonate (K ₂ CO ₃ , Na ₂ CO ₃ ) is manufactured through a coprecipitation or impregnation method, for example, K ₂ Mg (CO ₃ ) may include one or more selected from the group consisting of ₂ 4H ₂ O and KHMg (CO ₃ ) ₂ H ₂ O.

Alternatively, the alkali metal double salt-based adsorbent may include a first metal salt including a first metal selected from magnesium (Mg), calcium (Ca), strontium (Sr), and barium (Ba); And a double salt comprising a second metal salt comprising a second metal selected from lithium (Li), sodium (Na), potassium (K), rubidium (Rb) and cesium (Cs). It may be.

In one embodiment, the alkali metal double salt-based adsorbent may be a double salt-based material of Na and Mg based on sodium and magnesium.

In one embodiment, the hydrotalcite-based adsorbent may be synthesized by hydrothermal synthesis or coprecipitation by mixing the chloride represented by any one of the following formula 4 to 7 and the carbonate represented by the formula (8).

[Formula 4]

(1-x) M (OH) ₂

[Formula 5]

(1-x) M (NO ₃ ) ₂

[Formula 6]

xL (OH) ₃

[Formula 7]

xL (NO ₃ ) ₃

[Formula 8]

(x / 2) A ₂ CO ₃

(In the formulas 4 to 8, x has a value of 0.17 ~ 0.4, M is selected from the group consisting of magnesium (Mg), zinc (Zn) and nickel (Ni), L is aluminum (Al), gallium ( Ga), iron (Fe) and manganese (Mn), and A is selected from the group consisting of sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr). Can be chosen)

On the other hand, the adsorbent for carbon dioxide capture may further include a carbonate-based adsorbent, in which case the adsorption performance may be increased.

In one embodiment, the adsorbent for collecting carbon dioxide may further include potassium carbonate (K ₂ CO ₃ ).

For example, the adsorbent for collecting carbon dioxide may be an Mg / Al-based hydrotalcite-based adsorbent impregnated with K ₂ CO ₃ .

In general, the water gas conversion reaction represented by Chemical Formula 3 has an issue that the carbon monoxide conversion is higher as the reaction temperature is lower due to an exothermic reaction, but the reaction rate is slower. However, in the present invention, since carbon dioxide is adsorbed immediately after being produced in the same reactor, the forward reaction of the water gas shift reaction is further promoted, thereby overcoming the thermodynamic limitation of the catalytic reaction.

In an exemplary embodiment, the hydrogen generation catalyst and the adsorbent for collecting carbon dioxide may be included in a weight ratio of 1: 9 to 9: 1, and specifically, may be included in a weight ratio of 1: 4 to 4: 1. It may be mixed or individually mixed in the reactor. When the weight ratio of the hydrogen generation catalyst and the adsorbent for carbon dioxide capture exceeds 9: 1, the catalytic reaction for hydrogen production may not occur smoothly.

In an exemplary embodiment, the gas conversion unit 200 may be appropriately adjusted according to the type of catalyst and adsorbent. For example, the temperature of the gas conversion unit 200 may be maintained at a temperature of 200 to 500 ℃ and specifically may be maintained at a temperature of 250 to 340 ℃.

On the other hand, the gas conversion unit 200 is further connected to the heat transfer unit 250 for transferring the waste heat of the dry reforming reaction unit 100 to the gas conversion unit 200, the heat transfer unit 250 is a steam generator for generating steam ( (Not shown) and a preheating unit (not shown) for preheating the syngas generated in the dry reforming reaction unit. The preheating unit may be operated by the heat of the waste heat of the dry reforming reaction unit.

In addition, although not shown, the gas switching unit 200 may further be connected to a hydrogen gas collecting unit for collecting the generated hydrogen gas. Accordingly, high purity hydrogen can be collected without a separate separation process.

The dry reforming reaction unit of the hydrogen producer autonomous of the present invention includes a catalyst optimized for the dry reforming reaction. Accordingly, the reforming reaction using a large amount of biogas may proceed with high efficiency. In addition, since the gas conversion unit of the hydrogen production apparatus of the present invention directly captures carbon dioxide, the performance of the reaction for generating hydrogen in the gas conversion unit can be maintained without deterioration. Accordingly, hydrogen production performance can be greatly improved.

Hydrogen Production Method

In another embodiment of the present invention, a hydrogen production method for producing hydrogen on the same principle as the hydrogen production apparatus is provided. Since the hydrogen production method includes the same or similar configuration as the hydrogen production apparatus, a detailed description thereof will be omitted.

The hydrogen production method includes a first step of producing a synthesis gas by directly reacting methane and carbon dioxide in the biogas in a dry reforming reaction unit; A second step of generating carbon dioxide and hydrogen by reacting carbon monoxide in the syngas generated through the dry reforming reaction unit with a water vapor in a gas conversion unit, and collecting the generated carbon dioxide; It includes.

In the first step, a perovskite catalyst may be used when syngas is produced by directly reacting methane and carbon dioxide in the biogas.

On the other hand, in the second step, the carbon dioxide collected according to the reaction of the carbon monoxide and water vapor may be recycled when the reaction with the methane in the biogas in the first step.

In an exemplary embodiment, the gas conversion unit in which the second step is performed includes a hydrogen generating catalyst and an adsorbent for collecting carbon dioxide, and the hydrogen generating catalyst and an adsorbent for collecting carbon dioxide are in a weight ratio of 1: 9 to 9: 1, Specifically, it may be included in a weight ratio of 1: 4 to 4: 1.

On the other hand, the waste heat generated during the synthesis gas production of the first step may react with the carbon dioxide and water vapor in the second step, and recycle when collecting the carbon dioxide.

Hereinafter, the present invention will be described in more detail with reference to Examples. These examples are only for illustrating the present invention, it will be apparent to those skilled in the art that the scope of the present invention is not to be construed as limited by these embodiments.

Example

Experimental Example 1: Preparation of the catalyst for dry reforming and XRD analysis confirmation]

Preparation of Catalyst 1

3.064 g of yttrium nitrate [Y (NO ₃ ) ₃ H ₂ O (Aldrich)] and 19.469 g of strontium nitrate [Sr (NO ₃ ) ₃ H ₂ O (Aldrich)] were dissolved in DI water at the same time. 28.13 g of titanium isopropoxide [Ti (OCH (CH ₃ ) ₂ ) ₄ (Aldrich)] and 76.8 g of citric acid were sufficiently dissolved in 200 g of ethylene glycol, followed by ruthenium chloride [(Cl ₃ Ru.xH ₂ O) (Junsei) 0.622 g was dissolved in DI water for stabilization. Each solution was mixed together at 80 ° C. for 24 hours to give Sr _{0 . 92} Y _{0 . 08} Ti _{0 . 97} Ru _{0 .} A gel solution containing ₀₃ O _{3 -δ} was prepared (Ru doped 3%). After drying at 110 ° C., heat treatment was performed at 650 ° C. for 5 hours under air conditions. Accordingly, Sr _{0 . 92} Y _{0 . 08} Ti _{0 . 97} Ru _{0 .} A catalyst comprising ₀₃ O _{3 -δ} was prepared.

Preparation of Catalyst 2

In preparing catalyst 1, a catalyst was prepared by following the same process except that the mixture was heat-treated under hydrogen and 900 ° C for 5 hours instead of air and 650 ° C.

Preparation of Catalyst 3

In preparing catalyst 1, the catalyst was prepared by following the same process except that ruthenium chloride [(Cl ₃ Ru.xH ₂ O) (Junsei)] was not dissolved.

XRD Analysis

Then, to evaluate the composition of the catalysts 1 to 3, the X-ray diffraction analysis (X-ray Diffraction, XRD) was performed on the catalyst. The result is as shown in FIG.

Referring to FIG. 6, the catalysts 1 and 2 have a perovskite structure of SrTiO ₃ as a basic structure, and part of strontium (Sr) is doped with yttrium (Y) and part of titanium (Ti) with nickel (Ru), respectively. It can be seen that it is a homogeneous catalyst substituted with a single phase. In addition, it can be seen that they can be easily prepared through the Pechini method (Pechini method) using distilled water or deionized water other than ethanol as a solvent.

Experimental Example 2: Confirming Adsorbent Performance

7 is a gas conversion unit (adsorbent (Mg / Al-based hydrotalcite-based adsorbent impregnated with K ₂ CO ₃ ) + catalyst (Cu / ZnO / Al ₂ O ₃ ) from the different gas composition shown in Table 1 It is the result of numerical simulation of the water gas shift reaction using the catalyst). Considering table 1, as to impede the forward reaction of the impurity is water gas shift reaction included in the synthesis gas from through a commercial gasification CO conversion and the H ₂ production rate has been confirmed as low compared to the ideal feed conditions, Gross H ₂ production rate of most It was measured higher than the ideal condition.

Commercializer Company yCO yH ₂ yCO ₂ yinert yH ₂ O Gas 1 ideal 0.25 0.75 Gas 2 KBR-Powder River Basin
Oxygen-enriched Air 0.08 0.132 0.134 0.414 0.24 Gas 3 KBR-Powder River Basin (Air) 0.067 0.06 0.076 0.596 0.201 Gas 4 British Gas Lurgi- Illinois No.6 0.207 0.113 0.016 0.043 0.621 Gas 5 British Gas Lurgi- Powder River Basin 0.209 0.115 0.017 0.032 0.627 Gas 6 GE (Texaco)-Illinois No. 6 (Before quench) 0.182 0.177 0.08 0.015 0.546 Gas 7 GE (Texaco)-Illinois No. 6 (After quench) 0.182 0.178 0.08 0.014 0.546 Gas 8 conocophillips E-Gas- Pittsburgh No.8 0.196 0.155 0.046 0.015 0.588 Gas 9 conocophillips E-Gas- Powder River Basin 0.174 0.186 0.105 0.013 0.522 Gas 10 Shell-Illinois No.6 0.213 0.108 0.008 0.032 0.639

In addition, referring to FIG. 7, when a mixture other than carbon dioxide and steam is included, the conversion rate due to the catalytic reaction is observed to be reduced by the thermodynamic equilibrium law. I could see the improvement. Accordingly, it was confirmed that the hydrogen generation efficiency is very excellent when manufacturing the gas conversion unit as in the present invention.

Experimental Example 3: Checking Gas Switching Part Performance

Manufacture of gas switch

8a and 8b show examples that simulate the adsorption unit and the water gas shift reaction experimentally. First, 35 wt% of potassium carbonate (K) in a commercial hydrogen production catalyst (ShiftMax 210, Sud-Chemie; present Clarient) and a commercial hydrotalcite adsorbent (MG70, Sasol GmbH, Germany) having a composition of Cu / ZnO / Al ₂ O ₃ Adsorbent impregnated with ₂ CO ₃ ) was used. For the experiment, a homogeneous mixture in which the catalyst and the adsorbent are uniformly prepared was prepared, wherein the mixing ratio of the hydrogen generating catalyst and the adsorbent was 4: 1 and the mixing ratio of the hydrogen generating catalyst and the adsorbent was 1: 4. It was. Thereafter, the mixtures were molded into cylindrical pellets and filled in the gas conversion unit. At reaction conditions (300 ° C., 19 vol% CO, 57 vol% H ₂ O), the water gas shift reaction is performed when the ratio of catalyst and adsorbent is 4: 1 (FIG. 8A) and 1: 4 (FIG. 8B), respectively. It was confirmed that carbon dioxide produced as a reaction by-product was removed by the hydrotalcite-based adsorbent while producing a high-purity hydrogen. In addition, it was confirmed that the high purity hydrogen production time is longer than when a larger amount of adsorbent is charged inside the column.

[Experimental Example 4: Evaluation of the linkage between the dry reforming reaction unit and the gas conversion unit]

Dry reforming reaction unit and gas conversion unit connection

Figures 9a and 9b shows an embodiment simulated experimentally in conjunction with the dry reforming reaction unit and the gas conversion unit using the methane and carbon dioxide contained in the biogas. For the implementation of the dry reforming reaction, Sr _{0 . 92} Y _{0 . 08} Ti _{0 . 95} Ru _{0 . 05} O _{3 - δ} catalyst was used in the gas conversion unit commercial hydrogen generating catalyst (ShiftMax 210, Sud-Chemie; now Clarient) and a commercial hydrotalcite adsorbent having a composition of Cu / ZnO / Al ₂ O ₃ (MG70, Sasol GmbH, Germany) was charged with an adsorbent impregnated with 35 wt% potassium carbonate (K ₂ CO ₃ ). At this time, the ratio of the catalyst and the adsorbent in the gas conversion unit was set to 1: 4 by mass ratio. For the reaction, methane / carbon dioxide mixed gas was injected into the dry reforming reaction unit at 1: 3 (volume ratio), and additional steam was injected from the steam generator between the dry reforming reaction unit and the gas conversion unit. At this time, the flow rate of the steam was set to a volume ratio of three times the amount of carbon monoxide generated from the methane and carbon dioxide injected into the dry reforming reaction unit. The internal temperature of the dry reforming reaction unit and the gas conversion unit was set to 800 ° C. and 300 ° C., respectively, and the gas flow rate generated in the gas conversion unit was confirmed by using a gas analyzer after removing all moisture contained through the condenser. Figure 9a shows the gas composition changes over time when the gas conversion unit is linked to the two reactors in the state without the adsorbent in the same reaction conditions. From the results, it can be seen that the carbon monoxide generated in the dry reforming reaction unit is additionally converted to carbon dioxide and hydrogen in the gas conversion unit. On the other hand, the experimental results when the adsorbent is included in the gas conversion unit (Fig. 9b), by the hydrotalcite-based adsorbent containing both carbon dioxide contained in the exhaust gas of the dry reforming reaction unit and carbon dioxide additionally generated as a reaction by-product in the gas conversion unit At the same time, it was confirmed that high purity hydrogen was produced during the same time. The concentration of hydrogen produced during the reaction time with the adsorption part was about 99.95%, and it was confirmed that no by-product gas except for unreacted methane was detected in the dry reforming reaction part. Accordingly, it was confirmed that the hydrogen production apparatus in which the dry reforming reaction unit and the gas conversion unit are connected has a very high efficiency of generating high purity hydrogen.

The embodiments of the present invention described above should not be construed as limiting the technical idea of the present invention. The protection scope of the present invention is limited only by the matters described in the claims, and those skilled in the art can change and change the technical idea of the present invention in various forms. Accordingly, such improvements and modifications will fall within the protection scope of the present invention as long as it will be apparent to those skilled in the art.

100: dry reforming reaction unit
200: gas conversion unit
250: heat transfer unit

Claims (14)

A dry reforming reaction unit for directly reacting methane and carbon dioxide in the biogas to produce a synthesis gas including hydrogen; And
A gas conversion unit for generating carbon dioxide and hydrogen by reacting carbon monoxide in the synthesis gas generated through the dry reforming reaction unit with steam, and collecting the generated carbon dioxide; Including;
The carbon dioxide collected according to the reaction of the carbon monoxide and water vapor is recycled when reacting with the methane in the biogas in the dry reforming reaction unit,
The gas conversion unit includes a hydrogen generating catalyst and an adsorbent for collecting carbon dioxide, and the hydrogen generating catalyst and an adsorbent for collecting carbon dioxide are included in a weight ratio of 1: 9 to 9: 1,
The dry reforming reaction part includes a catalyst including a compound represented by the following [Formula 6], and the catalyst including the compound represented by the [Formula 6] is operated at a temperature of 700 to 900 ° C. for 60 to 120 hours. Hydrogen production device with methane conversion of over 80%.
[Formula 6]
Sr _1-y Y _y Ti _1-x Ru _x O _3-δ
(Where x is greater than 0 and less than 1. y is greater than 0 and less than 0.1. Δ is greater than 0 and less than 1). delete delete The method of claim 1,
Always hydrogen generating catalyst is a hydrogen production apparatus comprising at least one transition metal selected from the group consisting of Cu, Ni and Fe. The method of claim 1,
The adsorbent for collecting carbon dioxide includes an alkali metal double salt-based adsorbent or a hydrotalcite-based adsorbent. The method of claim 5,
The alkali metal double salt-based adsorbent is an adsorbent prepared by coprecipitation or impregnation of alkaline earth metal carbonate,
The hydrotalcite-based adsorbent is hydrogen production, which is an adsorbent prepared through hydrothermal synthesis or coprecipitation by mixing a chloride represented by any one of the following [Formula 1] to [Formula 4] and a carbonate represented by [Formula 5]. Device.
[Formula 1]
(1-x) M (OH) ₂
[Formula 2]
(1-x) M (NO ₃ ) ₂
[Formula 3]
xL (OH) ₃
[Formula 4]
xL (NO ₃ ) ₃
[Formula 5]
(x / 2) A ₂ CO ₃
(In the formula 1 to 5, x has a value of 0.17 ~ 0.4, M is selected from the group consisting of magnesium (Mg), zinc (Zn) and nickel (Ni), L is aluminum (Al), gallium ( Ga), iron (Fe) and manganese (Mn), and A is selected from the group consisting of sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr). Can be chosen) delete delete The method of claim 1,
The hydrogen production apparatus further includes a heat transfer unit for transferring the waste heat of the dry reforming reaction unit to the gas conversion unit,
The heat transfer unit comprises a steam generator for generating steam; And a preheating unit for preheating the synthesis gas generated in the dry reforming reaction unit. The method of claim 9,
Always preheating unit is a hydrogen production apparatus that operates the waste heat of the dry reforming reaction unit as a heat source. The method of claim 1,
Hydrogen production apparatus further comprises a hydrogen gas collecting unit connected to the gas conversion unit. As a hydrogen production method through a hydrogen production apparatus including a dry reforming reaction unit and a gas conversion unit,
In the dry reforming reaction unit, by directly reacting methane and carbon dioxide in the biogas to produce a synthesis gas; And
In the gas conversion unit, by reacting carbon monoxide in the synthesis gas generated through the dry reforming reaction unit with water vapor to produce carbon dioxide and hydrogen, and collecting the generated carbon dioxide; Including;
The carbon dioxide collected according to the reaction of the carbon monoxide and water vapor is recycled when reacting with the methane in the biogas in the dry reforming reaction unit,
The gas conversion unit includes a hydrogen generating catalyst and an adsorbent for collecting carbon dioxide, and the hydrogen generating catalyst and an adsorbent for collecting carbon dioxide are included in a weight ratio of 1: 9 to 9: 1,
The dry reforming reaction part includes a catalyst including a compound represented by the following [Formula 6], and the catalyst including the compound represented by the [Formula 6] is operated at a temperature of 700 to 900 ° C. for 60 to 120 hours. Hydrogen production method with methane conversion of 80% or more.
[Formula 6]
Sr _1-y Y _y Ti _1-x Ru _x O _3-δ
(Where x is greater than 0 and less than 1. y is greater than 0 and less than 0.1. Δ is greater than 0 and less than 1). delete delete

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